Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "fastwave_backend"
+name = "fastwave"
 version = "0.1.0"
 edition = "2021"
 
@@ -10,7 +10,7 @@ debug = 1
 
 [dependencies]
 num = "0.4"
-clap = { version = "4.4.6", features = ["derive"] }
+clap = { version = "3.1.8", features = ["derive"] }
 chrono = "0.4"
-# TODO : remove itertools once date parser is reworked.
+itertools = "0.10.3"
-itertools = "0.11"
+backtrace = "0.3"

LICENSE-YEHOWSHUA

@@ -1,2 +0,0 @@
-This codebase is also licensed to Yehowshua Immanuel to use
-in any manner Yehowshua Immanuel sees fit.

README.md

@@ -1,80 +1,30 @@
-Copyright(2023) - Yehowshua Immanuel
+Copyright - Yehowshua Immanuel
-
-# Vision
-Imagine being able to visualize a CPU pipeline diagram by merely loading a simulation waveform dump, sprinkling in a bit of code, and dragging and dropping some diagram blocks into the visualizer. This project aims to offer such an experience.
-
-Since this project is written in Rust, it should also be able to run in the browser via web-assembly.
-
-# Status
-As of January 2024, work on the Fastwave Backend is stalled. It has been a fun journey watching Fastwave enable the first iterations of the [surfer waveform viewer](https://surfer-project.org). Now surfer uses an even better backend called [Wellen](https://github.com/ekiwi/wellen?tab=readme-ov-file). Go check it out! I hear it's really good. Perhaps I will soon archive the Fastwave Backend.
-
-Browser demo: https://app.surfer-project.org/
-
-Screenshot of surfer frontend below:
-<img width="1609" alt="image" src="https://github.com/ThePerfectComputer/FastWaveBackend/assets/103011002/63deffc0-98b0-405f-b093-74d10b422b01">
 
 # A High performance, VCD Parser written in Rust
 
-I hope for a GUI that eventually looks like the following...
+## Current Features
-
+ - pretty fast, parses 3.04 GB VCD file in ~27.23s on M1 Macbook Air with 
-![](assets/FastWaveMockup.png)
+   respect to 30s with GTKWave on the same device. FastWave currently
-
+   offers highly robust error(at least on the sample VCD files in this
-# Current Features
+   repository) handling which GTKWave doesn't have.
-
- - Robust Error Handling
-   
-   FastWave currently offers highly robust error handling(at least on the sample 
-   VCD files in this repository) which GTKWave doesn't have. For
-   example, selecting the ``UTILIZATON_ENABLED`` signal after opening 
-   [test2x2_regex22_string1.vcd](./test-vcd-files/xilinx_isim/test2x2_regex22_string1.vcd)
-   (one of the sample xilinx vcd test files) in GtkWave, will crash GtkWave since
-   this signal is malformed. FastWave on the otherhand simply notes that the
-   signal is malformed.
-
-# Performance
-
-## Methods
-I have been testing performance on a 3.04GB VCD file that can be found 
-[here](https://drive.google.com/file/d/1pfm2qo2l8fGTHHJ8TLrg1vSGaV_TUbp2/view?usp=sharing).
-
-For getting the GtkWave results, I fired up GtkWave, clicked on 
-``File``->``Open New Window``, and selected the VCD file linked to above.
-I started my stopwatch as soon as I pressed enter to beging loading the VCD
-file, and stopped my stopwatch once the GtkWave titlebar reached 100%.
-   
-To get the memory consumption, I opened Activity Monitor on Mac, and recorded
-the GtkWave memory usage before and after loading the large VCD file, and 
-took the difference.
    
    I noticed that when running FastWave in the VsCode terminal as opposed
-to the MacOS system terminal or the Lapce terminal, FastWave is notably
+   to the MacOS system terminal or the Lapce terminal.
-slower.
-
-## Results
-
-LZ4 should really improve memory usage once I add it. Note that GTKWave uses LZ4 on the fly.
-
-| Software | Time(s) | Memory(MB) |
-|----------|---------|------------|
-| FastWave | ~27.30  | 1100+      |
-| GtkWave  | ~30     | 89.8       |
 
 
 # Current Limitations
 Unable to handle VCD files that have signals with more than 
 2^32 - 1 = 4,294,967,295 deltas/changes.
 
-# Running
+## Running
 
 This repository comes with several smaller VCD files emitted from
 various EDA tools. If you want a larger VCD file, grab one from
 [here](https://drive.google.com/file/d/1pfm2qo2l8fGTHHJ8TLrg1vSGaV_TUbp2/view?usp=sharing).
 
-Here are some examples you can run:
 The first build of the program may take some time.
 
-1. ``cargo run --release --example parse_vcd tests/vcd-files/aldec/SPI_Write.vcd``
+``cargo run --release test-vcd-files/aldec/SPI_Write.vcd``
-2. ``cargo run --release --example vcd``
 
 You can run all the tests with ``cargo test``
 
@@ -83,49 +33,31 @@ You may wish to test the parser on a malformed VCD just to make
 sure that the parser gives useful/sane errors.
 
 Here's a command to test on a malformed VCD:
-``cargo run --release --example parse_vcd tests/vcd-files/VCD_file_with_errors.vcd``
+`cargo run --release test-vcd-files/VCD_file_with_errors.vcd`
 
 
 # TODO
 
-## Features and Other
+## Features
- - [ ] add documenting comments
+ - [ ] macro for getting line number when propagating errors
- - [ ] make signal query private until later?
+ - [ ] search for any ok_or's
- - [ ] add signal query code to example once interface is finalized
+ - [ ] search for any unwraps or any direct vectors indexing
- - [ ] change crate name to vcd_fast_parse
+ - [ ] re-order all signal timelines as binary balanced trees with respect to timestamps
- - [ ] perhaps we should be looking up signal values on the VCD class
+       - support multithreaded re-ordering
- - [ ] perhaps we should be returning signal trees from the VCD class
+ - [ ] looks into making a macro for filename and linenumber later
- - [ ] add lz4 compression support and compare memory perf before and after
-       - [ ] may need to refactor with allow for get_mut for dynamic
-             compression-decompression for multiple signal structs 
-             at once to allow for multi-threading
- - [ ] test against large waveforms from the
-       [verilog-vcd-parser](https://github.com/ben-marshall/verilog-vcd-parser)
-       tool
- - [ ] (a bit of work) consolidate error messages in validation phase
- - [ ] once the access patterns of the GUI frontend are well understood,
-       create specific functions and restrict as many types to private
-       as possible
  - [ ] Print out git commit or release number.
- - [ ] do a read through all the code - look for uneeded code
+ - [ ] Should be able to load waveform whilst viewing it live.
- - [ ] Move part of the performance section to another markdown file.
+       - could be quite challenging to implement for various reasons
+ - [ ] Take a look at GTKWave parser to compare efficiency.
 
 ## Repairs
- - [ ] replace str bracket indices with get(slice)
  - [ ] make a custom date parser for possibly up to 18 different versions(that is, for each possible tool).
  - [ ] Consolidate error messages and add cursors throughout.
- - [ ] Add file and line to the enum errors.
  - [ ] Fix warnings especially usage and restriction warnings once I'm
        able to successfully parse all sample VCDs.
 
 ## Code Consistency
- - [ ] Change error messages to line and filenames. Go through all calls to unwrap.
+ - [ ] Change error messages to line and filenames. Go through all calls to ``format!`` whilst also keeping performance in mind.
-   - [ ] search for any unwraps or any direct vectors indexing
- - [ ] Handle TODOs
- - [ ] Remove debug code/comments.
-
-## Documentation
- - [ ] Document indexing structure with diagram and possibly include the rational
 
 ## Marketing
- - [ ] Send survey to community 
+ - [ ] Send survey to community channel.

examples/parse_vcd.rs

@@ -1,33 +0,0 @@
-// Copyright (C) 2022 Yehowshua Immanuel
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
-use clap::Parser;
-use std::fs::File;
-
-use fastwave_backend::parse_vcd;
-
-#[derive(Parser)]
-struct Cli {
-    /// The path to the file to read
-    path: std::path::PathBuf,
-}
-
-fn main() -> std::io::Result<()> {
-    let args = Cli::parse();
-
-    use std::time::Instant;
-
-    let now = Instant::now();
-    let file = File::open(&args.path)?;
-    parse_vcd(file).unwrap();
-    let elapsed = now.elapsed();
-
-    println!(
-        "Parsed VCD file {} : {:.2?}",
-        &args.path.as_os_str().to_str().unwrap(),
-        elapsed
-    );
-
-    Ok(())
-}

examples/vcd.rs

@@ -1,81 +0,0 @@
-// Copyright (C) 2022 Yehowshua Immanuel
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
-use std::fs::File;
-
-use fastwave_backend::{parse_vcd, ScopeIdx, SignalIdx, VCD};
-
-fn indented_print(indent: u8, name: &String) {
-    for _ in 0..indent {
-        print!("  |");
-    }
-    print!("---");
-    println!("{name}");
-}
-
-// TODO: refactor into more general visitor pattern that takes a
-// function as an argument.
-fn visit_all_scopes(vcd: &VCD) {
-    fn visit_all_scope_children(root_idx: ScopeIdx, vcd: &VCD, indent: u8) {
-        if vcd.child_scopes_by_idx(root_idx).is_empty() {
-        } else {
-            for child_scope_idx in vcd.child_scopes_by_idx(root_idx) {
-                indented_print(indent, vcd.scope_name_by_idx(child_scope_idx));
-                for signal_idx in vcd.get_children_signal_idxs(child_scope_idx) {
-                    let signal = vcd.signal_from_signal_idx(signal_idx);
-                    let SignalIdx(idx) = signal_idx;
-                    indented_print(indent + 1, &format!("{},{}", signal.name(), idx));
-                }
-                visit_all_scope_children(child_scope_idx, vcd, indent + 1);
-            }
-        }
-    }
-    for root_scope_idx in vcd.root_scopes_by_idx() {
-        indented_print(0, vcd.scope_name_by_idx(root_scope_idx));
-        visit_all_scope_children(root_scope_idx, vcd, 1u8);
-    }
-}
-
-fn main() -> std::io::Result<()> {
-    use std::time::Instant;
-
-    // we start by printing out the entire signal tree of
-    // a parsed VCD
-    let now = Instant::now();
-    let file_path = "tests/vcd-files/icarus/CPU.vcd";
-    let file = File::open(file_path)?;
-    let vcd = parse_vcd(file).unwrap();
-    let elapsed = now.elapsed();
-    println!("Parsed VCD file {} : {:.2?}", file_path, elapsed);
-
-    println!("Printing Scopes");
-    visit_all_scopes(&vcd);
-    println!("Done Printing Scopes");
-    println!();
-
-    // we then parse another VCD, print its signal tree and
-    // query some values on its timeline
-    let now = Instant::now();
-    let file_path = "tests/vcd-files/amaranth/up_counter.vcd";
-    let file = File::open(file_path)?;
-    let vcd = parse_vcd(file).unwrap();
-    let elapsed = now.elapsed();
-    println!("Parsed VCD file {} : {:.2?}", file_path, elapsed);
-
-    println!("Printing Scopes");
-    visit_all_scopes(&vcd);
-    println!("Done Printing Scopes");
-
-    let state_signal = vcd.signal_from_signal_idx(SignalIdx(4));
-    let name = state_signal.name();
-
-    let timestamps = vec![31499_000u32, 31500_000u32, 57760_000u32];
-    for timestamp in timestamps {
-        let time = num::BigUint::from(timestamp);
-        let val = state_signal.query_string_val_on_tmln(&time, &vcd).unwrap();
-        println!("Signal `{name}` has value `{val}` at time `{time}`");
-    }
-
-    Ok(())
-}

src/lib.rs

@@ -1,12 +0,0 @@
-// Copyright (C) 2022 Yehowshua Immanuel
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
-
-mod vcd;
-pub use vcd::parse::parse_vcd;
-pub use vcd::signal::{Signal, SignalType, SignalValue, SignalErrors};
-pub use vcd::types::{Metadata, Timescale, Version};
-pub use vcd::types::{ScopeIdx, SignalIdx, VCD};
-
-pub use num::BigUint;

src/main.rs

@@ -0,0 +1,39 @@
+use std::{fs::File};
+use clap::Parser;
+
+pub mod test;
+
+pub mod vcd;
+use vcd::parse_vcd;
+
+use std::mem::size_of_val;
+
+#[derive(Parser)]
+struct Cli {
+    /// The path to the file to read
+    #[clap(parse(from_os_str))]
+    path: std::path::PathBuf}
+
+fn main() -> std::io::Result<()> {
+    let args = Cli::parse();
+
+    use std::time::Instant;
+    let now = Instant::now();
+
+    let file = File::open(&args.path)?;
+    let vcd = parse_vcd(file).unwrap(); 
+
+    let elapsed = now.elapsed();
+    println!("Elapsed: {:.2?}", elapsed);
+
+    vcd.print_longest_signal();
+    dbg!(size_of_val(&*vcd.timeline));
+    // unsafe {
+    //     let sz = size_of_val(&*vcd.timeline);
+    // }
+
+    // println!("printing signal tree");
+    // vcd.print_scopes();
+
+    Ok(())
+}

src/test.rs

@@ -0,0 +1,2 @@
+mod files;
+pub use files::*;

src/test/files.rs

@@ -0,0 +1,71 @@
+// TODO: we should eventually be able to only test on just
+// the files const
+pub const FILES : [&str; 30] = [
+    "./test-vcd-files/aldec/SPI_Write.vcd",
+    "./test-vcd-files/ghdl/alu.vcd",
+    "./test-vcd-files/ghdl/idea.vcd",
+    "./test-vcd-files/ghdl/pcpu.vcd",
+    "./test-vcd-files/gtkwave-analyzer/perm_current.vcd",
+    "./test-vcd-files/icarus/CPU.vcd",
+    "./test-vcd-files/icarus/rv32_soc_TB.vcd",
+    "./test-vcd-files/icarus/test1.vcd",
+    "./test-vcd-files/model-sim/CPU_Design.msim.vcd",
+    "./test-vcd-files/model-sim/clkdiv2n_tb.vcd",
+    "./test-vcd-files/my-hdl/Simple_Memory.vcd",
+    "./test-vcd-files/my-hdl/sigmoid_tb.vcd",
+    "./test-vcd-files/my-hdl/top.vcd",
+    "./test-vcd-files/ncsim/ffdiv_32bit_tb.vcd",
+    "./test-vcd-files/quartus/mipsHardware.vcd",
+    "./test-vcd-files/quartus/wave_registradores.vcd",
+    "./test-vcd-files/questa-sim/dump.vcd",
+    "./test-vcd-files/questa-sim/test.vcd",
+    "./test-vcd-files/riviera-pro/dump.vcd",
+    "./test-vcd-files/systemc/waveform.vcd",
+    "./test-vcd-files/treadle/GCD.vcd",
+    "./test-vcd-files/vcs/Apb_slave_uvm_new.vcd",
+    "./test-vcd-files/vcs/datapath_log.vcd",
+    "./test-vcd-files/vcs/processor.vcd",
+    "./test-vcd-files/verilator/swerv1.vcd",
+    "./test-vcd-files/verilator/vlt_dump.vcd",
+    "./test-vcd-files/vivado/iladata.vcd",
+    "./test-vcd-files/xilinx_isim/test.vcd",
+    "./test-vcd-files/xilinx_isim/test1.vcd",
+    // TODO : add signal ignore list to handle bitwidth mismatches
+    "./test-vcd-files/xilinx_isim/test2x2_regex22_string1.vcd"
+];
+
+pub const GOOD_DATE_FILES : [&str; 24] = [
+    "./test-vcd-files/aldec/SPI_Write.vcd",
+    "./test-vcd-files/ghdl/alu.vcd",
+    "./test-vcd-files/ghdl/idea.vcd",
+    "./test-vcd-files/ghdl/pcpu.vcd",
+    "./test-vcd-files/gtkwave-analyzer/perm_current.vcd",
+    "./test-vcd-files/icarus/CPU.vcd",
+    "./test-vcd-files/icarus/rv32_soc_TB.vcd",
+    "./test-vcd-files/icarus/test1.vcd",
+    "./test-vcd-files/model-sim/CPU_Design.msim.vcd",
+    "./test-vcd-files/model-sim/clkdiv2n_tb.vcd",
+    "./test-vcd-files/my-hdl/Simple_Memory.vcd",
+    "./test-vcd-files/my-hdl/sigmoid_tb.vcd",
+    "./test-vcd-files/my-hdl/top.vcd",
+    "./test-vcd-files/questa-sim/dump.vcd",
+    "./test-vcd-files/questa-sim/test.vcd",
+    "./test-vcd-files/riviera-pro/dump.vcd",
+    "./test-vcd-files/vcs/Apb_slave_uvm_new.vcd",
+    "./test-vcd-files/vcs/datapath_log.vcd",
+    "./test-vcd-files/vcs/processor.vcd",
+    "./test-vcd-files/verilator/swerv1.vcd",
+    "./test-vcd-files/verilator/vlt_dump.vcd",
+    "./test-vcd-files/xilinx_isim/test.vcd",
+    "./test-vcd-files/xilinx_isim/test1.vcd",
+    "./test-vcd-files/xilinx_isim/test2x2_regex22_string1.vcd"
+];
+
+pub const BAD_DATE_FILES : [&str; 6] = [
+    "./test-vcd-files/ncsim/ffdiv_32bit_tb.vcd",
+    "./test-vcd-files/quartus/mipsHardware.vcd",
+    "./test-vcd-files/quartus/wave_registradores.vcd",
+    "./test-vcd-files/systemc/waveform.vcd",
+    "./test-vcd-files/treadle/GCD.vcd",
+    "./test-vcd-files/vivado/iladata.vcd",
+];

src/vcd.rs

@@ -1,10 +1,8 @@
-// Copyright (C) 2022 Yehowshua Immanuel
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
-
-pub(crate) mod parse;
 mod reader;
-pub(crate) mod signal;
+pub use reader::*;
-pub(crate) mod types;
+
-mod utilities;
+mod types;
+pub use types::*;
+
+mod parse;
+pub use parse::*;

src/vcd/parse.rs

@@ -1,35 +1,191 @@
-// Copyright (C) 2022 Yehowshua Immanuel
+use num::BigInt;
-// This program is distributed under both the GPLV3 license
+use std::collections::HashMap;
-// and the YEHOWSHUA license, both of which can be found at
+use std::fs::File;
-// the root of the folder containing the sources for this program.
+
+use super::*;
 
 mod combinator_atoms;
-mod events;
+use combinator_atoms::*;
-mod metadata;
+
-mod scopes;
 mod types;
+use types::*;
 
-pub fn parse_vcd(file: impl std::io::Read) -> Result<super::types::VCD, String> {
+mod metadata;
-    let mut word_gen = super::reader::WordReader::new(file);
+use metadata::*;
 
-    let header = metadata::parse_metadata(&mut word_gen)?;
+mod scopes;
+use scopes::*;
+
+mod events;
+use events::*;
+
+use std::cmp::Ordering;
+
+fn compare_strs(a: &str, b: &str) -> Ordering {
+    // choose the smaller of the two indices
+    let upper_bound = if a.len() > b.len() { b.len() } else { a.len() };
+    let a_as_bytes = a.as_bytes();
+    let b_as_bytes = b.as_bytes();
+
+    for i in 0..upper_bound {
+        let a_byte = a_as_bytes[i];
+        let b_byte = b_as_bytes[i];
+        if a_byte > b_byte {
+            return Ordering::Greater;
+        }
+        if b_byte > a_byte {
+            return Ordering::Less;
+        }
+    }
+
+    if a.len() > b.len() {
+        return Ordering::Greater;
+    }
+
+    if a.len() < b.len() {
+        return Ordering::Less;
+    }
+
+    return Ordering::Equal;
+}
+
+fn ordered_binary_lookup(map: &Vec<(String, SignalIdx)>, key: &str) -> Result<SignalIdx, String> {
+    let mut upper_idx = map.len() - 1;
+    let mut lower_idx = 0usize;
+
+    while lower_idx <= upper_idx {
+        let mid_idx = lower_idx + ((upper_idx - lower_idx) / 2);
+        let (str_val, signal_idx) = map.get(mid_idx).unwrap();
+        let ordering = compare_strs(key, str_val.as_str());
+
+        match ordering {
+            Ordering::Less => {
+                upper_idx = mid_idx - 1;
+            }
+            Ordering::Equal => {
+                return Ok(*signal_idx);
+            }
+            Ordering::Greater => {
+                lower_idx = mid_idx + 1;
+            }
+        }
+    }
+
+    return Err(format!(
+        "Error near {}:{}. Unable to find key: `{key}` in the map.",
+        file!(),
+        line!()
+    ));
+}
+
+pub fn parse_vcd(file: File) -> Result<VCD, String> {
+    let mut word_gen = WordReader::new(file);
+
+    let header = parse_metadata(&mut word_gen)?;
 
     // later, we'll need to map parsed ascii symbols to their
     // respective signal indexes
     let mut signal_map = std::collections::HashMap::new();
 
     // after we parse metadata, we form the VCD object
-    let mut vcd = super::types::VCD {
+    let mut vcd = VCD {
         metadata: header,
-        tmstmps_encoded_as_u8s: vec![],
+        timeline: vec![],
+        timeline_markers: vec![],
         all_signals: vec![],
         all_scopes: vec![],
-        root_scopes: vec![],
+        scope_roots: vec![],
-        largest_timestamp: None,
     };
 
-    scopes::parse_scopes(&mut word_gen, &mut vcd, &mut signal_map)?;
+    parse_scopes(&mut word_gen, &mut vcd, &mut signal_map)?;
-    events::parse_events(&mut word_gen, &mut vcd, &mut signal_map)?;
+
+    // the signal map should not contain any empty string
+    for (k, v) in &signal_map {
+        if k.len() == 0 {
+            return Err(format!("Critical error near {}:{}. There should be no empty strings in vcd string -> SignalIdx hashmap.", file!(), line!()));
+        }
+    }
+
+    // now that we've parsed all scopes and filled the hashmap
+    // with signals, we convert hashmap to an ordered vector
+    let mut signal_map1: Vec<(String, SignalIdx)> = signal_map
+        .iter()
+        .map(|(string, idx)| (string.clone(), idx.clone()))
+        .collect();
+    signal_map1.sort_by(|a: &(String, SignalIdx), b: &(String, SignalIdx)| {
+        let a = &a.0;
+        let b = &b.0;
+        compare_strs(a, b)
+    });
+
+    for (k, v) in &signal_map1 {
+        let signal_idx = ordered_binary_lookup(&signal_map1, k.as_str())?;
+        assert!(*v == signal_idx);
+    }
+
+    // let now = std::time::Instant::now();
+    // for (k, v) in &signal_map1 {
+    //     let signal_idx = ordered_binary_lookup(&signal_map1, k.as_str())?;
+    //     assert!(*v == signal_idx);
+    // }
+    // let ordered_binary_search_elapsed = now.elapsed();
+    // println!(
+    //     "ordered_binary_search_elapsed: {:.2?}",
+    //     ordered_binary_search_elapsed
+    // );
+
+    // let now = std::time::Instant::now();
+    // for (k, v) in &signal_map1 {
+    //     // let signal_idx = ordered_binary_lookup(&signal_map1, k.as_str())?;
+    //     let signal_idx = signal_map.get(k).unwrap();
+    //     assert!(*v == *signal_idx);
+    // }
+    // let hashmap_search_elapsed = now.elapsed();
+    // println!("hashmap_search_elapsed: {:.2?}", hashmap_search_elapsed);
+
+    parse_events(&mut word_gen, &mut vcd, &mut signal_map)?;
 
     Ok(vcd)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test;
+    use std::fs::File;
+    #[test]
+    fn headers() {
+        // TODO: eventually, once all dates pass, merge the following
+        // two loops
+        // testing dates
+        for file in test::GOOD_DATE_FILES {
+            let metadata = parse_metadata(&mut WordReader::new(File::open(file).unwrap()));
+            assert!(metadata.is_ok());
+            assert!(metadata.unwrap().date.is_some());
+        }
+
+        for file in test::FILES {
+            let metadata = parse_metadata(&mut WordReader::new(File::open(file).unwrap()));
+            assert!(metadata.is_ok());
+
+            let (scalar, _timescale) = metadata.unwrap().timescale;
+            assert!(scalar.is_some());
+        }
+    }
+
+    #[test]
+    fn scopes() {
+        // see if we can parse all signal trees successfully
+        for file_name in test::FILES {
+            let file = File::open(file_name).unwrap();
+            let vcd = parse_vcd(file);
+
+            if !vcd.is_ok() {
+                dbg!(file_name);
+                vcd.unwrap();
+            }
+
+            // assert!(vcd.is_ok());
+        }
+    }
+}

src/vcd/parse/combinator_atoms.rs

@@ -1,49 +1,53 @@
-// Copyright (C) 2022 Yehowshua Immanuel
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
-use super::super::reader::{next_word, WordReader};
 use super::types::ParseResult;
+use super::reader::WordReader;
 
 pub(super) fn digit(chr : u8) -> bool {
-    let zero = b'0';
+    let zero = b'0' as u8;
-    let nine = b'9';
+    let nine = b'9' as u8;
 
-    (chr >= zero) && (nine >= chr)
+    let between_zero_and_nine = (chr >= zero) && (nine >= chr);
+
+    return between_zero_and_nine
 }
 
-pub(super) fn take_until(word: &str, pattern: u8) -> ParseResult<'_> {
+pub(super) fn take_until<'a>(word : &'a str, pattern : u8) -> ParseResult<'a> {
     let mut new_start  = 0;
 
     for chr in word.as_bytes() {
         if *chr == pattern {
-            break;
+            break
-        } else {
+        } 
+        else {
             new_start += 1;
         }
     }
 
+    return 
         ParseResult{
             matched  : &word[0..new_start],
-        residual: &word[new_start..],
+            residual : &word[new_start..]
-    }
+        };
+
 }
 
-pub(super) fn take_while(word: &str, cond: fn(u8) -> bool) -> ParseResult<'_> {
+pub(super) fn take_while<'a>(word : &'a str, cond : fn(u8) -> bool) -> ParseResult<'a> {
     let mut new_start  = 0;
 
     for chr in word.as_bytes() {
         if cond(*chr) {
             new_start += 1;
-        } else {
+        } 
-            break;
+        else {
+            break
         }
     }
 
+    return 
         ParseResult{
             matched  : &word[0..new_start],
-        residual: &word[new_start..],
+            residual : &word[new_start..]
-    }
+        };
+
 }
 
 pub(super) fn tag<'a>(word : &'a str, pattern : &'a str) -> ParseResult<'a> {
@@ -55,29 +59,30 @@ pub(super) fn tag<'a>(word: &'a str, pattern: &'a str) -> ParseResult<'a> {
     let mut res = true;
     for (c_lhs, c_rhs) in iter {
         res = res && (c_lhs == c_rhs);
-        if !res {
+        if !res {break}
-            break;
-        }
         new_start += 1;
     }
 
+    return 
         ParseResult{
             matched  : &word[0..new_start],
-        residual: &word[new_start..],
+            residual : &word[new_start..]
-    }
+        };
 }
 
-pub(super) fn ident<R: std::io::Read>(
+pub(super) fn ident(
-    word_reader: &mut WordReader<R>,
+    word_reader : &mut WordReader,
     keyword : &str, 
 ) -> Result<(), String> {
     // let keyword = "module";
-    let (word, cursor) = next_word!(word_reader)?;
+
+    let (word, cursor) = word_reader.next_word()?;
 
     if word == keyword {
-        Ok(())
+        return Ok(())
-    } else {
+    }
+    else {
         let err = format!("found keyword `{word}` but expected `{keyword}` on {cursor:?}");
-        Err(err)
+        return Err(err)
     }
 }

src/vcd/parse/events.rs

@@ -1,30 +1,98 @@
-// Copyright (C) 2022 Yehowshua Immanuel
+//! part of the vcd parser that handles parsing the signal tree and
-// This program is distributed under both the GPLV3 license
+//! building the resulting signal tree
-// and the YEHOWSHUA license, both of which can be found at
+use core::time;
-// the root of the folder containing the sources for this program.
 
-use num::BigUint;
+use super::*;
-use std::collections::HashMap;
 
-use super::super::reader::{next_word, Cursor, Line, Word, WordReader};
+#[derive(Debug)]
-use super::super::signal::{LsbIdxOfTmstmpValOnTmln, SignalEnum};
+pub(super) enum BinaryParserErrTypes {
-use super::super::types::{SignalIdx, VCD};
+    XValue,
-use super::super::utilities::{binary_str_to_vec_u8, BinaryParserErrTypes};
+    ZValue,
+    UValue,
+    OtherValue(char),
+    TooLong,
+}
 
-pub(super) fn parse_events<R: std::io::Read>(
+// We build a quick and not so dirty bit string parser.
-    word_reader: &mut WordReader<R>,
+fn base2_str_to_byte(word: &[u8]) -> Result<u8, BinaryParserErrTypes> {
-    vcd: &mut VCD,
+    let mut val = 0u8;
+
+    // shouldn't have more than 8 chars in str
+    let len = word.len();
+    if len > 8 {
+        return Err(BinaryParserErrTypes::TooLong);
+    }
+
+    let bit_lut = [
+        0b0000_0001u8,
+        0b0000_0010u8,
+        0b0000_0100u8,
+        0b0000_1000u8,
+        0b0001_0000u8,
+        0b0010_0000u8,
+        0b0100_0000u8,
+        0b1000_0000u8,
+    ];
+
+    for (idx, chr) in word.iter().rev().enumerate() {
+        match chr {
+            b'1' => val = bit_lut[idx] | val,
+            b'0' => {}
+            b'x' | b'X' => return Err(BinaryParserErrTypes::XValue),
+            b'z' | b'Z' => return Err(BinaryParserErrTypes::ZValue),
+            b'u' | b'U' => return Err(BinaryParserErrTypes::UValue),
+            _ => return Err(BinaryParserErrTypes::OtherValue(*chr as char)),
+        }
+    }
+
+    Ok(val)
+}
+
+fn binary_str_to_vec_u8(binary_str: &str) -> Result<Vec<u8>, BinaryParserErrTypes> {
+    let mut vec_u8: Vec<u8> = Vec::new();
+    let binary_str_as_bytes = binary_str.as_bytes();
+
+    let mut tail_idx = binary_str_as_bytes.len();
+    // clamp head if provided binary str is less than 8 long
+    let mut head_idx = if tail_idx >= 8 {
+        binary_str_as_bytes.len() - 8
+    } else {
+        0
+    };
+    while tail_idx > 0 {
+        let curr_b_val = &binary_str_as_bytes[head_idx..tail_idx];
+        let val_u8 = base2_str_to_byte(curr_b_val)?;
+        vec_u8.push(val_u8);
+
+        if head_idx < 8 {
+            head_idx = 0
+        } else {
+            head_idx = head_idx - 8;
+        }
+
+        if tail_idx < 8 {
+            tail_idx = 0
+        } else {
+            tail_idx = tail_idx - 8;
+        }
+    }
+    Ok(vec_u8)
+}
+
+pub(super) fn parse_events<'a>(
+    word_reader: &mut WordReader,
+    vcd: &'a mut VCD,
     signal_map: &mut HashMap<String, SignalIdx>,
 ) -> Result<(), String> {
-    let mut curr_tmstmp_lsb_idx = 0u32;
+    // let hash_time = std::time::Duration::ZERO;
-    let mut curr_tmstmp_len_u8 = 0u8;
+    // let hash_time = std::time::Duration::ZERO;
+
     loop {
         let next_word = word_reader.next_word();
-
         // The following is the only case where eof is not an error.
         // If we've reached the end of the file, then there is obviously
         // nothing left to do...
-        if next_word.is_none() {
+        if next_word.is_err() {
             break;
         };
 
@@ -39,55 +107,34 @@ pub(super) fn parse_events<R: std::io::Read>(
             "#" => {
                 let value = &word[1..];
                 let (f, l) = (file!(), line!());
-                let value_biguint = BigUint::parse_bytes(value.as_bytes(), 10)
+                let value = BigInt::parse_bytes(value.as_bytes(), 10).ok_or(
-                    .ok_or(())
+                    format!("Error near {f}:{l}. Failed to parse {value} as BigInt at {cursor:?}")
-                    .map_err(|_| {
+                        .as_str(),
-                        format!(
+                )?;
-                            "Error near {f}:{l}. Failed to parse {value} as BigInt at {cursor:?}"
+                let (_, mut value) = value.to_bytes_le();
-                        )
-                    })?;
-                let mut value = value_biguint.to_bytes_le();
                 // TODO : u32 helps with less memory, but should ideally likely be
                 // configurable.
-                curr_tmstmp_len_u8 = u8::try_from(value.len()).map_err(|_| {
+                let (f, l) = (file!(), line!());
-                    format!(
+                let start_idx = u32::try_from(vcd.timeline.len()).map_err(|_| {
-                        "Error near {}:{}. Failed to convert from usize to u8.",
+                    format!("Error near {f}:{l}. Failed to convert from usize to u32.")
-                        file!(),
-                        line!()
-                    )
                 })?;
-                curr_tmstmp_lsb_idx =
+                vcd.timeline_markers.push(StartIdx(start_idx));
-                    u32::try_from(vcd.tmstmps_encoded_as_u8s.len()).map_err(|_| {
+                vcd.timeline.append(&mut value);
-                        format!(
-                            "Error near {}:{}. Failed to convert from usize to u32.",
-                            file!(),
-                            line!()
-                        )
-                    })?;
-                vcd.tmstmps_encoded_as_u8s.append(&mut value);
-                vcd.largest_timestamp = Some(value_biguint);
             }
 
             // handle the case of an n bit signal whose value must be parsed
             "b" => {
                 let binary_value = &word[1..];
-                let observed_num_bits = u32::try_from(binary_value.len()).map_err(|_| {
+                let observed_num_bits = binary_value.len();
-                    format!(
-                        "Error near {}:{}, {cursor:?}. \
-                        Found signal with more than 2^32 - 1 bits.",
-                        file!(),
-                        line!()
-                    )
-                })?;
 
                 let mut value_u8: Vec<u8> = Vec::new();
                 let mut value_string = String::new();
 
                 let mut store_as_string = false;
 
-                // If we encounter other values than 0 or 1, we can recover from
+                // If we encounter x or z in a value, we can recover from
                 // the error and store the value as a string.
-                // Or else, we propagate up other errors.
+                // Or else, we we propagate up other errors.
                 match binary_str_to_vec_u8(binary_value) {
                     Ok(result) => {
                         value_u8 = result;
@@ -95,15 +142,10 @@ pub(super) fn parse_events<R: std::io::Read>(
                     Err(
                         BinaryParserErrTypes::XValue
                         | BinaryParserErrTypes::ZValue
-                        | BinaryParserErrTypes::UValue
+                        | BinaryParserErrTypes::UValue,
-                        | BinaryParserErrTypes::WValue
-                        | BinaryParserErrTypes::HValue
-                        | BinaryParserErrTypes::DashValue
-                        | BinaryParserErrTypes::LValue,
                     ) => {
                         store_as_string = true;
-                        // Turn to lower case for consistency
+                        value_string = binary_value.to_string();
-                        value_string = binary_value.to_ascii_lowercase();
                     }
                     Err(e) => {
                         let (f, l) = (file!(), line!());
@@ -114,10 +156,10 @@ pub(super) fn parse_events<R: std::io::Read>(
                 }
 
                 // this word should be the signal alias
-                let (word, cursor) = next_word!(word_reader)?;
+                let (word, cursor) = word_reader.next_word().unwrap();
 
                 // lookup signal idx
-                let signal_idx = signal_map.get(word).ok_or(()).map_err(|_| {
+                let SignalIdx(ref signal_idx) = signal_map.get(word).ok_or(()).map_err(|_| {
                     format!(
                         "Error near {}:{}. Failed to lookup signal {word} at {cursor:?}",
                         file!(),
@@ -125,25 +167,34 @@ pub(super) fn parse_events<R: std::io::Read>(
                     )
                 })?;
 
-                let signal = vcd.dealiasing_signal_idx_to_signal_lookup_mut(signal_idx)?;
+                // account for fact that signal idx could be an alias, so there
-
+                // could be one step of indirection
+                let signal_idx = {
+                    let signal = vcd.all_signals.get(*signal_idx).unwrap();
                     match signal {
-                    SignalEnum::Data {
+                        Signal::Data { .. } => *signal_idx,
+                        Signal::Alias { signal_alias, .. } => {
+                            let SignalIdx(ref signal_idx) = signal_alias;
+                            signal_idx.clone()
+                        }
+                    }
+                };
+
+                // after handling potential indirection, go ahead and update the timeline
+                // of the signal signal_idx references
+                let signal = vcd.all_signals.get_mut(signal_idx).unwrap();
+                match signal {
+                    Signal::Data {
                         name,
-                        signal_type,
+                        sig_type,
                         ref mut signal_error,
                         num_bits,
-                        num_bytes,
+                        u8_timeline,
-                        nums_encoded_as_fixed_width_le_u8,
+                        u8_timeline_markers,
-                        string_vals,
+                        string_timeline,
-                        lsb_indxs_of_num_tmstmp_vals_on_tmln,
+                        string_timeline_markers,
-                        byte_len_of_num_tmstmp_vals_on_tmln,
-                        lsb_indxs_of_string_tmstmp_vals_on_tmln,
-                        byte_len_of_string_tmstmp_vals_on_tmln,
                         ..
                     } => {
-                        // we've already identified in a prior loop iteration that the signal has
-                        // an error
                         if signal_error.is_some() {
                             continue;
                         }
@@ -158,7 +209,7 @@ pub(super) fn parse_events<R: std::io::Read>(
                                     let (f, l) = (file!(), line!());
                                     let msg = format!("\
                                         Error near {f}:{l}. The bitwidth for signal {name} \
-                                        of signal_type {signal_type:?} is expected to be `{num_bits}` not \
+                                        of sig_type {sig_type:?} is expected to be `{num_bits}` not \
                                         `{observed_num_bits}`. \
                                         This error occurred while parsing the vcd file at \
                                         {cursor:?}");
@@ -171,7 +222,7 @@ pub(super) fn parse_events<R: std::io::Read>(
                                 let msg = format!(
                                     "\
                                     Error near {f}:{l}. The bitwidth for signal {name} \
-                                    must be specified for a signal of type {signal_type:?}. \
+                                    must be specified for a signal of type {sig_type:?}. \
                                     This error occurred while parsing the vcd file at \
                                     {cursor:?}"
                                 );
@@ -179,46 +230,47 @@ pub(super) fn parse_events<R: std::io::Read>(
                             }
                         };
 
+                        let (f, l) = (file!(), line!());
+                        let timeline_idx = u32::try_from(vcd.timeline.len()).map_err(|_| {
+                            format!("Error near {f}:{l}. Failed to convert from usize to u32.")
+                        })?;
+                        let timeline_idx = TimelineIdx(timeline_idx);
+
                         if store_as_string {
-                            lsb_indxs_of_string_tmstmp_vals_on_tmln
+                            string_timeline_markers.push(timeline_idx);
-                                .push(LsbIdxOfTmstmpValOnTmln(curr_tmstmp_lsb_idx));
+                            string_timeline.push(value_string);
-                            byte_len_of_string_tmstmp_vals_on_tmln.push(curr_tmstmp_len_u8);
-                            string_vals.push(value_string);
                             Ok(())
                         } else {
-                            // timestamp stuff
+                            u8_timeline_markers.push(timeline_idx);
-                            lsb_indxs_of_num_tmstmp_vals_on_tmln
+
-                                .push(LsbIdxOfTmstmpValOnTmln(curr_tmstmp_lsb_idx));
+                            let mut curr_num_bytes = value_u8.len();
-                            byte_len_of_num_tmstmp_vals_on_tmln.push(curr_tmstmp_len_u8);
+                            u8_timeline.append(&mut value_u8);
 
-                            // value stuff
                             // we may need to zero extend values
                             // so that we end up storing all values
                             // of a particular signal in a consistent
                             // amount of bytes
-                            let bytes_required = num_bytes.ok_or_else(|| {
+                            let num_bits = num_bits.unwrap();
-                                format!("Error near {}:{}. num_bytes empty.", file!(), line!())
+                            let bytes_required =
-                            })?;
+                                (num_bits / 8) + if (num_bits % 8) > 0 { 1 } else { 0 };
-                            let mut curr_num_bytes =
-                                u16::try_from(value_u8.len()).map_err(|_| {
-                                    format!(
-                                        "Error near {}:{}. \
-                                     Found signal {name} with with value change of greater \
-                                     than 2^32 - 1 bits on {cursor:?}.",
-                                        file!(),
-                                        line!()
-                                    )
-                                })?;
 
-                            nums_encoded_as_fixed_width_le_u8.append(&mut value_u8);
                             while curr_num_bytes < bytes_required {
-                                nums_encoded_as_fixed_width_le_u8.push(0u8);
+                                // useful for debugging
+                                // let err = format!("Error at {cursor:?}.\
+                                // num_bits = {num_bits}, \
+                                // observed_bits = {observed_num_bits}, \
+                                // curr_num_bytes = {curr_num_bytes}, \
+                                // bytes_required = {bytes_required} \
+                                // for signal {name}");
+                                // Err(err)?;
+
+                                u8_timeline.push(0u8);
                                 curr_num_bytes += 1;
                             }
                             Ok(())
                         }
                     }
-                    SignalEnum::Alias { .. } => {
+                    Signal::Alias { .. } => {
                         let (f, l) = (file!(), line!());
                         let msg = format!(
                             "Error near {f}:{l}, a signal alias should not point to a signal alias.\n\
@@ -232,7 +284,8 @@ pub(super) fn parse_events<R: std::io::Read>(
             "0" => {
                 // lookup signal idx
                 let hash = &word[1..];
-                let signal_idx = signal_map.get(hash).ok_or(()).map_err(|_| {
+                let (f, l) = (file!(), line!());
+                let SignalIdx(ref signal_idx) = signal_map.get(hash).ok_or(()).map_err(|_| {
                     format!(
                         "Error near {}:{}. Failed to lookup signal {hash} at {cursor:?}",
                         file!(),
@@ -240,18 +293,30 @@ pub(super) fn parse_events<R: std::io::Read>(
                     )
                 })?;
 
-                let signal = vcd.dealiasing_signal_idx_to_signal_lookup_mut(signal_idx)?;
+                // account for fact that signal idx could be an alias, so there
-
+                // could be one step of indirection
+                let signal_idx = {
+                    let signal = vcd.all_signals.get(*signal_idx).unwrap();
                     match signal {
-                    SignalEnum::Data {
+                        Signal::Data { .. } => *signal_idx,
+                        Signal::Alias { signal_alias, .. } => {
+                            let SignalIdx(ref signal_idx) = signal_alias;
+                            signal_idx.clone()
+                        }
+                    }
+                };
+
+                // after handling potential indirection, go ahead and update the timeline
+                // of the signal signal_idx references
+                let signal = vcd.all_signals.get_mut(signal_idx).unwrap();
+                match signal {
+                    Signal::Data {
                         name,
-                        signal_type,
+                        sig_type,
                         ref mut signal_error,
                         num_bits,
-                        num_bytes,
+                        u8_timeline,
-                        nums_encoded_as_fixed_width_le_u8,
+                        u8_timeline_markers,
-                        lsb_indxs_of_num_tmstmp_vals_on_tmln,
-                        byte_len_of_num_tmstmp_vals_on_tmln,
                         ..
                     } => {
                         // if this is a bad signal, go ahead and skip it
@@ -268,7 +333,7 @@ pub(super) fn parse_events<R: std::io::Read>(
                                     let msg = format!(
                                         "\
                                         Error near {f}:{l}. The bitwidth for signal {name} \
-                                        of signal_type {signal_type:?} is expected to be `1` not \
+                                        of sig_type {sig_type:?} is expected to be `1` not \
                                         `{num_bits}`. \
                                         This error occurred while parsing the vcd file at \
                                         {cursor:?}"
@@ -282,35 +347,25 @@ pub(super) fn parse_events<R: std::io::Read>(
                                 let msg = format!(
                                     "\
                                     Error near {f}:{l}. The bitwidth for signal {name} \
-                                    must be specified for a signal of type {signal_type:?}. \
+                                    must be specified for a signal of type {sig_type:?}. \
                                     This error occurred while parsing the vcd file at \
                                     {cursor:?}"
                                 );
                                 Err(msg)?;
                             }
                         };
-                        // timestamp stuff
-                        lsb_indxs_of_num_tmstmp_vals_on_tmln
-                            .push(LsbIdxOfTmstmpValOnTmln(curr_tmstmp_lsb_idx));
-                        byte_len_of_num_tmstmp_vals_on_tmln.push(curr_tmstmp_len_u8);
 
-                        // value stuff
+                        let (f, l) = (file!(), line!());
-                        // we may need to zero extend values
+                        let timeline_idx = u32::try_from(vcd.timeline.len()).map_err(|_| {
-                        // so that we end up storing all values
+                            format!("Error near {f}:{l}. Failed to convert from usize to u32.")
-                        // of a particular signal in a consistent
-                        // amount of bytes
-                        let bytes_required = num_bytes.ok_or_else(|| {
-                            format!("Error near {}:{}. num_bytes empty.", file!(), line!())
                         })?;
-                        nums_encoded_as_fixed_width_le_u8.push(0u8);
+                        let timeline_idx = TimelineIdx(timeline_idx);
-                        let mut curr_num_bytes = 1;
+
-                        while curr_num_bytes < bytes_required {
+                        u8_timeline_markers.push(timeline_idx);
-                            nums_encoded_as_fixed_width_le_u8.push(0u8);
+                        u8_timeline.push(0u8);
-                            curr_num_bytes += 1;
-                        }
                         Ok(())
                     }
-                    SignalEnum::Alias { .. } => {
+                    Signal::Alias { .. } => {
                         let (f, l) = (file!(), line!());
                         let msg = format!(
                             "Error near {f}:{l}, a signal alias should not point to a signal alias.\n\
@@ -323,7 +378,7 @@ pub(super) fn parse_events<R: std::io::Read>(
             "1" => {
                 // lokup signal idx
                 let hash = &word[1..];
-                let signal_idx = signal_map.get(hash).ok_or(()).map_err(|_| {
+                let SignalIdx(ref signal_idx) = signal_map.get(hash).ok_or(()).map_err(|_| {
                     format!(
                         "Error near {}:{}. Failed to lookup signal {hash} at {cursor:?}",
                         file!(),
@@ -331,18 +386,30 @@ pub(super) fn parse_events<R: std::io::Read>(
                     )
                 })?;
 
-                let signal = vcd.dealiasing_signal_idx_to_signal_lookup_mut(signal_idx)?;
+                // account for fact that signal idx could be an alias, so there
-
+                // could be one step of indirection
+                let signal_idx = {
+                    let signal = vcd.all_signals.get(*signal_idx).unwrap();
                     match signal {
-                    SignalEnum::Data {
+                        Signal::Data { .. } => *signal_idx,
+                        Signal::Alias { signal_alias, .. } => {
+                            let SignalIdx(ref signal_idx) = signal_alias;
+                            signal_idx.clone()
+                        }
+                    }
+                };
+
+                // after handling potential indirection, go ahead and update the timeline
+                // of the signal signal_idx references
+                let signal = vcd.all_signals.get_mut(signal_idx).unwrap();
+                match signal {
+                    Signal::Data {
                         name,
-                        signal_type,
+                        sig_type,
                         ref mut signal_error,
                         num_bits,
-                        num_bytes,
+                        u8_timeline,
-                        nums_encoded_as_fixed_width_le_u8,
+                        u8_timeline_markers,
-                        lsb_indxs_of_num_tmstmp_vals_on_tmln,
-                        byte_len_of_num_tmstmp_vals_on_tmln,
                         ..
                     } => {
                         // if this is a bad signal, go ahead and skip it
@@ -359,7 +426,7 @@ pub(super) fn parse_events<R: std::io::Read>(
                                     let msg = format!(
                                         "\
                                         Error near {f}:{l}. The bitwidth for signal {name} \
-                                        of signal_type {signal_type:?} is expected to be `1` not \
+                                        of sig_type {sig_type:?} is expected to be `1` not \
                                         `{num_bits}`. \
                                         This error occurred while parsing the vcd file at \
                                         {cursor:?}"
@@ -373,35 +440,25 @@ pub(super) fn parse_events<R: std::io::Read>(
                                 let msg = format!(
                                     "\
                                     Error near {f}:{l}. The bitwidth for signal {name} \
-                                    must be specified for a signal of type {signal_type:?}. \
+                                    must be specified for a signal of type {sig_type:?}. \
                                     This error occurred while parsing the vcd file at \
                                     {cursor:?}"
                                 );
                                 Err(msg)?;
                             }
                         };
-                        // timestamp stuff
-                        lsb_indxs_of_num_tmstmp_vals_on_tmln
-                            .push(LsbIdxOfTmstmpValOnTmln(curr_tmstmp_lsb_idx));
-                        byte_len_of_num_tmstmp_vals_on_tmln.push(curr_tmstmp_len_u8);
 
-                        // value stuff
+                        let (f, l) = (file!(), line!());
-                        // we may need to zero extend values
+                        let timeline_idx = u32::try_from(vcd.timeline.len()).map_err(|_| {
-                        // so that we end up storing all values
+                            format!("Error near {f}:{l}. Failed to convert from usize to u32.")
-                        // of a particular signal in a consistent
-                        // amount of bytes
-                        let bytes_required = num_bytes.ok_or_else(|| {
-                            format!("Error near {}:{}. num_bytes empty.", file!(), line!())
                         })?;
-                        nums_encoded_as_fixed_width_le_u8.push(1u8);
+                        let timeline_idx = TimelineIdx(timeline_idx);
-                        let mut curr_num_bytes = 1;
+
-                        while curr_num_bytes < bytes_required {
+                        u8_timeline_markers.push(timeline_idx);
-                            nums_encoded_as_fixed_width_le_u8.push(0u8);
+                        u8_timeline.push(1u8);
-                            curr_num_bytes += 1;
-                        }
                         Ok(())
                     }
-                    SignalEnum::Alias { .. } => {
+                    Signal::Alias { .. } => {
                         let (f, l) = (file!(), line!());
                         let msg = format!(
                             "Error near {f}:{l}, a signal alias should not point to a signal alias.\n\
@@ -410,14 +467,12 @@ pub(super) fn parse_events<R: std::io::Read>(
                     }
                 }?;
             }
-
             // other one bit cases
-            "x" | "X" | "z" | "Z" | "u" | "U" | "h" | "H" | "l" | "L" | "w" | "W" | "-" => {
+            "x" | "X" | "z" | "Z" | "u" | "U" => {
-                // Select value and turn to lowercase for consistency
+                let val = word.to_string();
-                let val = word[0..1].to_ascii_lowercase();
                 // lokup signal idx
                 let hash = &word[1..];
-                let signal_idx = signal_map.get(hash).ok_or(()).map_err(|_| {
+                let SignalIdx(ref signal_idx) = signal_map.get(hash).ok_or(()).map_err(|_| {
                     format!(
                         "Error near {}:{}. Failed to lookup signal {hash} at {cursor:?}",
                         file!(),
@@ -425,17 +480,30 @@ pub(super) fn parse_events<R: std::io::Read>(
                     )
                 })?;
 
-                let signal = vcd.dealiasing_signal_idx_to_signal_lookup_mut(signal_idx)?;
+                // account for fact that signal idx could be an alias, so there
-
+                // could be one step of indirection
+                let signal_idx = {
+                    let signal = vcd.all_signals.get(*signal_idx).unwrap();
                     match signal {
-                    SignalEnum::Data {
+                        Signal::Data { .. } => *signal_idx,
+                        Signal::Alias { signal_alias, .. } => {
+                            let SignalIdx(ref signal_idx) = signal_alias;
+                            signal_idx.clone()
+                        }
+                    }
+                };
+
+                // after handling potential indirection, go ahead and update the timeline
+                // of the signal signal_idx references
+                let signal = vcd.all_signals.get_mut(signal_idx).unwrap();
+                match signal {
+                    Signal::Data {
                         name,
-                        signal_type,
+                        sig_type,
                         ref mut signal_error,
                         num_bits,
-                        string_vals,
+                        string_timeline,
-                        byte_len_of_string_tmstmp_vals_on_tmln,
+                        string_timeline_markers,
-                        lsb_indxs_of_string_tmstmp_vals_on_tmln,
                         ..
                     } => {
                         // if this is a bad signal, go ahead and skip it
@@ -452,7 +520,7 @@ pub(super) fn parse_events<R: std::io::Read>(
                                     let msg = format!(
                                         "\
                                         Error near {f}:{l}. The bitwidth for signal {name} \
-                                        of signal_type {signal_type:?} is expected to be `1` not \
+                                        of sig_type {sig_type:?} is expected to be `1` not \
                                         `{num_bits}`. \
                                         This error occurred while parsing the vcd file at \
                                         {cursor:?}"
@@ -466,7 +534,7 @@ pub(super) fn parse_events<R: std::io::Read>(
                                 let msg = format!(
                                     "\
                                     Error near {f}:{l}. The bitwidth for signal {name} \
-                                    must be specified for a signal of type {signal_type:?}. \
+                                    must be specified for a signal of type {sig_type:?}. \
                                     This error occurred while parsing the vcd file at \
                                     {cursor:?}"
                                 );
@@ -474,62 +542,17 @@ pub(super) fn parse_events<R: std::io::Read>(
                             }
                         };
 
-                        // record timestamp at which this event occurs
-                        lsb_indxs_of_string_tmstmp_vals_on_tmln
-                            .push(LsbIdxOfTmstmpValOnTmln(curr_tmstmp_lsb_idx));
-                        byte_len_of_string_tmstmp_vals_on_tmln.push(curr_tmstmp_len_u8);
-
-                        // record value
-                        string_vals.push(val);
-                        Ok(())
-                    }
-                    SignalEnum::Alias { .. } => {
                         let (f, l) = (file!(), line!());
-                        let msg = format!(
+                        let timeline_idx = u32::try_from(vcd.timeline.len()).map_err(|_| {
-                            "Error near {f}:{l}, a signal alias should not point to a signal alias.\n\
+                            format!("Error near {f}:{l}. Failed to convert from usize to u32.")
-                             This error occurred while parsing vcd file at {cursor:?}");
-                        Err(msg)
-                    }
-                }?;
-            }
-            // Store real values as a string as well and let the user parse it to an f64
-            "s" | " S" | "r" | "R" => {
-                let val = word[1..].to_string();
-                let (hash, cursor) = next_word!(word_reader)?;
-                // lokup signal idx
-                let signal_idx = signal_map.get(hash).ok_or(()).map_err(|_| {
-                    format!(
-                        "Error near {}:{}. Failed to lookup signal {hash} at {cursor:?}",
-                        file!(),
-                        line!()
-                    )
                         })?;
+                        let timeline_idx = TimelineIdx(timeline_idx);
 
-                let signal = vcd.dealiasing_signal_idx_to_signal_lookup_mut(signal_idx)?;
+                        string_timeline_markers.push(timeline_idx);
-
+                        string_timeline.push(val);
-                match signal {
-                    SignalEnum::Data {
-                        ref mut signal_error,
-                        string_vals,
-                        byte_len_of_string_tmstmp_vals_on_tmln,
-                        lsb_indxs_of_string_tmstmp_vals_on_tmln,
-                        ..
-                    } => {
-                        // if this is a bad signal, go ahead and skip it
-                        if signal_error.is_some() {
-                            continue;
-                        }
-
-                        // record timestamp at which this event occurs
-                        lsb_indxs_of_string_tmstmp_vals_on_tmln
-                            .push(LsbIdxOfTmstmpValOnTmln(curr_tmstmp_lsb_idx));
-                        byte_len_of_string_tmstmp_vals_on_tmln.push(curr_tmstmp_len_u8);
-
-                        // record string value
-                        string_vals.push(val);
                         Ok(())
                     }
-                    SignalEnum::Alias { .. } => {
+                    Signal::Alias { .. } => {
                         let (f, l) = (file!(), line!());
                         let msg = format!(
                             "Error near {f}:{l}, a signal alias should not point to a signal alias.\n\
@@ -538,6 +561,7 @@ pub(super) fn parse_events<R: std::io::Read>(
                     }
                 }?;
             }
+
             _ => {}
         }
     }

src/vcd/parse/metadata.rs

@@ -1,15 +1,7 @@
-// Copyright (C) 2022 Yehowshua Immanuel
+use chrono::prelude::*;
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
-use chrono::prelude::{DateTime, Utc};
 use itertools::Itertools;
 
-use super::super::reader::{next_word, Cursor, WordReader};
+use super::*;
-use super::super::types::{Metadata, Timescale, Version};
-
-use super::combinator_atoms::{digit, tag, take_until, take_while};
-use super::types::ParseResult;
 
 pub(super) fn parse_date(
     word_and_ctx1 : (&str, &Cursor),
@@ -18,6 +10,7 @@ pub(super) fn parse_date(
     word_and_ctx4 : (&str, &Cursor),
     word_and_ctx5 : (&str, &Cursor),
 ) -> Result<DateTime<Utc>, String> {
+
     let day = {
         // check for another word in the file
         let (word, cursor) = word_and_ctx1;
@@ -27,7 +20,7 @@ pub(super) fn parse_date(
             let msg  = format!("Error near {}:{}.", file!(), line!());
             let msg2 = format!("{word} is not a valid weekday : expected one of {days:?}\n");
             let msg3 = format!("failure location: {cursor:?}");
-            return Err(format!("{}{}{}", msg, msg2, msg3));
+            return Err(format!("{}{}{}", msg, msg2, msg3))
         }
 
         word.to_string()
@@ -38,14 +31,16 @@ pub(super) fn parse_date(
         let (word, cursor) = word_and_ctx2;
 
         let months = [
-            "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sept", "Oct", "Nov", "Dec",
+            "Jan", "Feb", "Mar", "Apr", 
+            "May", "Jun", "Jul", "Aug", 
+            "Sept", "Oct", "Nov", "Dec", 
             ];
 
         if !months.contains(&word) {
             let msg  = format!("Error near {}:{}.", file!(), line!());
             let msg2 = format!("{word} is not a valid month : expected one of {months:?}\n");
             let msg3 = format!("failure location: {cursor:?}");
-            return Err(format!("{}{}{}", msg, msg2, msg3));
+            return Err(format!("{}{}{}", msg, msg2, msg3))
         }
 
         word.to_string()
@@ -57,14 +52,15 @@ pub(super) fn parse_date(
 
         let date : u8 = match word.to_string().parse() {
             Ok(date) => date,
-            Err(e) => return Err(format!("Error near {}:{}. {e}", file!(), line!())),
+            Err(e) => {return Err(format!("Error near {}:{}. {e}", file!(), line!()))}
         };
 
         if date > 31 {
             let msg  = format!("Error near {}:{}.", file!(), line!());
             let msg2 = format!("{word} is not a valid date : must be between 0 and 31\n");
             let msg3 = format!("failure location: {cursor:?}");
-            return Err(format!("{}{}{}", msg, msg2, msg3));
+            return Err(format!("{}{}{}", msg, msg2, msg3))
+
         }
 
         date.to_string()
@@ -76,9 +72,7 @@ pub(super) fn parse_date(
 
         let res = take_until(word, b':');
         res.assert_match()?;
-        let hh: u8 = res
+        let hh : u8 = res.matched.to_string()
-            .matched
-            .to_string()
                         .parse()
                         .map_err(|e| format!("Error near {}:{}. {e}", file!(), line!()))?;
 
@@ -86,16 +80,14 @@ pub(super) fn parse_date(
             let msg  = format!("Error near {}:{}.", file!(), line!());
             let msg2 = format!("{hh} is not a valid hour : must be between 0 and 23\n");
             let msg3 = format!("failure location: {cursor:?}");
-            return Err(format!("{}{}{}", msg, msg2, msg3));
+            return Err(format!("{}{}{}", msg, msg2, msg3))
         }
 
         // get minute
         let word = &res.residual[1..]; // chop off colon which is at index 0
         let res = take_until(word, b':');
         res.assert_match()?;
-        let mm: u8 = res
+        let mm : u8 = res.matched.to_string()
-            .matched
-            .to_string()
                         .parse()
                         .map_err(|e| format!("Error near {}:{}. {e}", file!(), line!()))?;
 
@@ -103,15 +95,14 @@ pub(super) fn parse_date(
             let msg  = format!("Error near {}:{}.", file!(), line!());
             let msg2 = format!("{mm} is not a valid minute : must be between 0 and 60\n");
             let msg3 = format!("failure location: {cursor:?}");
-            return Err(format!("{}{}{}", msg, msg2, msg3));
+            return Err(format!("{}{}{}", msg, msg2, msg3))
         }
 
         // get second
         // let ss : u8 = remainder.to_string().parse().unwrap();
         res.assert_residual()?;
         let residual = &res.residual[1..]; // chop of colon which is at index 0
-        let ss: u8 = residual
+        let ss : u8 = residual.to_string()
-            .to_string()
                         .parse()
                         .map_err(|e| format!("Error near {}:{}. {e}", file!(), line!()))?;
 
@@ -119,7 +110,7 @@ pub(super) fn parse_date(
             let msg  = format!("Error near {}:{}.", file!(), line!());
             let msg2 = format!("{ss} is not a valid second : must be between 0 and 60\n");
             let msg3 = format!("failure location: {cursor:?}");
-            return Err(format!("{}{}{}", msg, msg2, msg3));
+            return Err(format!("{}{}{}", msg, msg2, msg3))
         }
         (hh.to_string(), mm.to_string(), ss.to_string())
     };
@@ -133,107 +124,95 @@ pub(super) fn parse_date(
     // unfortunately, the minutes, seconds, and hour could occur in an 
     // unexpected order
     let full_date = format!("{day} {month} {date} {hh}:{mm}:{ss} {year}");
-    let full_date = DateTime::parse_from_str(full_date.as_str(), "%a %b %e %T %Y");
+    let full_date = Utc.datetime_from_str(full_date.as_str(), "%a %b %e %T %Y");
     if full_date.is_ok() {
-        return Ok(full_date.unwrap().into());
+        return Ok(full_date.unwrap())
     }
 
-    Err(format!(
+    Err(format!("Error near {}:{}. Failed to parse date.", file!(), line!()))
-        "Error near {}:{}. Failed to parse date.",
+
-        file!(),
-        line!()
-    ))
 }
 
-pub(super) fn parse_version<R: std::io::Read>(
+pub(super) fn parse_version(word_reader : &mut WordReader) -> Result<Version, String> {
-    word_reader: &mut WordReader<R>,
-) -> Result<Version, String> {
     let mut version = String::new();
 
     loop {
-        let (word, _) = next_word!(word_reader)?;
+        let (word, _) = word_reader.next_word()?;
 
         if word == "$end" {
             // truncate trailing whitespace
             let version = version[0..(version.len() -  1)].to_string();
-            return Ok(Version(version));
+            return Ok(Version(version))
-        } else {
+
+        }
+        else {
             version.push_str(word);
-            version.push(' ');
+            version.push_str(" ");
         }
     }
 }
 
-pub(super) fn parse_timescale<R: std::io::Read>(
+pub(super) fn parse_timescale(word_reader : &mut WordReader) -> Result<(Option<u32>, Timescale), String> {
-    word_reader: &mut WordReader<R>,
+
-) -> Result<(Option<u32>, Timescale), String> {
     // we might see `1ps $end` or `1 ps $end`
     // first get timescale
-    let (word, _) = next_word!(word_reader)?;
+    let (word, _) = word_reader.next_word()?;
-    let ParseResult { matched, residual } = take_while(word, digit);
+    let word = word.to_string();
+    let ParseResult{matched, residual} = take_while(word.as_str(), digit);
     let scalar = matched;
 
-    let scalar: u32 = scalar
+    let scalar : u32 = scalar.to_string().parse()
-        .to_string()
-        .parse()
                         .map_err(|e| format!("Error near {}:{}. {e}", file!(), line!()))?;
 
     let timescale = {
-        if residual.is_empty() {
+        if residual == "" {
-            let (word, _) = next_word!(word_reader)?;
+            let (word, _) = word_reader.next_word()?;
             let unit = match word {
-                "fs" => Ok(Timescale::Fs),
+                "fs" => {Ok(Timescale::Fs)}
-                "ps" => Ok(Timescale::Ps),
+                "ps" => {Ok(Timescale::Ps)}
-                "ns" => Ok(Timescale::Ns),
+                "ns" => {Ok(Timescale::Ns)}
-                "us" => Ok(Timescale::Us),
+                "us" => {Ok(Timescale::Us)}
-                "ms" => Ok(Timescale::Ms),
+                "ms" => {Ok(Timescale::Ms)}
-                "s" => Ok(Timescale::S),
+                "s"  => {Ok(Timescale::S)}
-                _ => Err(format!(
+                _    => {Err(format!("Error near {}:{}. Unknown unit {word}.", file!(), line!()))}
-                    "Error near {}:{}. Unknown unit {word}.",
+            }.unwrap();
-                    file!(),
-                    line!()
-                )),
-            }?;
         
             (Some(scalar), unit)
-        } else {
+        }
+        else {
             let unit = match residual {
-                "fs" => Ok(Timescale::Fs),
+                "fs" => {Ok(Timescale::Fs)}
-                "ps" => Ok(Timescale::Ps),
+                "ps" => {Ok(Timescale::Ps)}
-                "ns" => Ok(Timescale::Ns),
+                "ns" => {Ok(Timescale::Ns)}
-                "us" => Ok(Timescale::Us),
+                "us" => {Ok(Timescale::Us)}
-                "ms" => Ok(Timescale::Ms),
+                "ms" => {Ok(Timescale::Ms)}
-                "s" => Ok(Timescale::S),
+                "s"  => {Ok(Timescale::S)}
-                _ => Err(format!(
+                _    => {Err(format!("Error near {}:{}. Unknown unit {residual}.", file!(), line!()))}
-                    "Error near {}:{}. Unknown unit {residual}.",
+            }.unwrap();
-                    file!(),
-                    line!()
-                )),
-            }?;
         
             (Some(scalar), unit)
         }
     };
 
     // then check for the `$end` keyword
-    let (word, _) = next_word!(word_reader)?;
+    let (end, _) = word_reader.next_word()?;
-    tag(word, "$end").assert_match()?;
+    tag(end, "$end").assert_match()?;
+
+    return Ok(timescale);
 
-    Ok(timescale)
 }
 
-pub(super) fn parse_metadata<R: std::io::Read>(
+pub(super) fn parse_metadata(word_reader : &mut WordReader) -> Result<Metadata, String> {
-    word_reader: &mut WordReader<R>,
+
-) -> Result<Metadata, String> {
     let mut metadata = Metadata {
         date : None,
         version : None,
-        timescale: (None, Timescale::Unit),
+        timescale : (None, Timescale::Unit)
     };
 
     loop {
         // check for another word in the file
-        let (word, _) = next_word!(word_reader)?;
+        let (word, _) = word_reader.next_word()?;
 
         let ParseResult{matched, residual} = tag(word, "$");
         match matched {
@@ -259,7 +238,7 @@ pub(super) fn parse_metadata<R: std::io::Read>(
                         let mut lookahead_5_words : Vec<(String, Cursor)> = Vec::new();
 
                         for _ in 0..5 {
-                            let (word, cursor) = next_word!(word_reader)?;
+                            let (word, cursor) = word_reader.next_word()?;
                             let word = word.to_string();
                             match word.as_str() {
                                 "$end" => {
@@ -274,9 +253,7 @@ pub(super) fn parse_metadata<R: std::io::Read>(
 
                         // we no longer attempt to parse date if we weren't able to lookahead 5
                         // words
-                        if found_end {
+                        if found_end {continue}
-                            continue;
-                        }
 
                         let permutations =  lookahead_5_words
                                             .iter()
@@ -303,9 +280,10 @@ pub(super) fn parse_metadata<R: std::io::Read>(
 
                             // store date and exit loop if a match is found
                             if parsed_date.is_ok() {
-                                metadata.date = Some(parsed_date?);
+                                metadata.date = Some(parsed_date.unwrap());
-                                break;
+                                break
                             }
+
                         }
                     }
                     "version"   => {
@@ -320,8 +298,8 @@ pub(super) fn parse_metadata<R: std::io::Read>(
                             metadata.timescale = timescale.unwrap();
                         }
                     }
-                    "scope" => break,
+                    "scope"     => {break}
-                    "var" => break,
+                    "var"       => {break}
                     // we keep searching for words until we've found one of the following
                     // keywords, ["version", "timescale", "scope", "var"]
                     _ => {}
@@ -330,6 +308,7 @@ pub(super) fn parse_metadata<R: std::io::Read>(
             // if word does not start with `$`, then we keep looping
             _ => {}
         }
+
     }
-    Ok(metadata)
+    return Ok(metadata)
 }

src/vcd/parse/scopes.rs

@@ -1,189 +1,94 @@
-// Copyright (C) 2022 Yehowshua Immanuel
+//! part of the vcd parser that handles parsing the signal tree and
-// This program is distributed under both the GPLV3 license
+//! building the resulting signal tree
-// and the YEHOWSHUA license, both of which can be found at
+use super::*;
-// the root of the folder containing the sources for this program.
 
-/// part of the vcd parser that handles parsing the signal tree and
+pub(super) fn parse_var<'a>(
-/// building the resulting signal tree
+    word_reader      : &mut WordReader,
-use std::collections::HashMap;
-
-use super::super::reader::{curr_word, next_word, WordReader};
-use super::super::signal::{SignalEnum, SignalType};
-use super::super::types::{Scope, ScopeIdx, SignalIdx, VCD};
-
-use super::combinator_atoms::{ident, tag};
-use super::types::ParseResult;
-
-pub(super) fn parse_var<R: std::io::Read>(
-    word_reader: &mut WordReader<R>,
     parent_scope_idx : ScopeIdx,
-    vcd: &mut VCD,
+    vcd              : &'a mut VCD,
-    signal_map: &mut HashMap<String, SignalIdx>,
+    signal_map       : &mut HashMap<String, SignalIdx>
-    path: &Vec<String>,
 ) -> Result<(), String> {
-    let (word, cursor) = next_word!(word_reader)?;
+    let (word, cursor) = word_reader.next_word()?;
-    let expected_types = [
+    let expected_types = ["integer", "parameter", "real", "reg", "string", "wire", "tri1", "time"];
-        "event",
-        "integer",
-        "parameter",
-        "real",
-        "realtime",
-        "reg",
-        "string",
-        "supply0",
-        "supply1",
-        "time",
-        "tri",
-        "triand",
-        "trior",
-        "trireg",
-        "tri0",
-        "tri1",
-        "wand",
-        "wire",
-        "wor",
-    ];
 
     // $var parameter 3 a IDLE $end
     //      ^^^^^^^^^ - var_type
     let var_type = match word {
-        "event" => Ok(SignalType::Event),
+        "integer"    => {Ok(SigType::Integer)}
-        "integer" => Ok(SignalType::Integer),
+        "parameter"  => {Ok(SigType::Parameter)}
-        "parameter" => Ok(SignalType::Parameter),
+        "real"       => {Ok(SigType::Real)}
-        "real" => Ok(SignalType::Real),
+        "reg"        => {Ok(SigType::Reg)}
-        "realtime" => Ok(SignalType::RealTime),
+        "string"     => {Ok(SigType::Str)}
-        "reg" => Ok(SignalType::Reg),
+        "wire"       => {Ok(SigType::Wire)}
-        "string" => Ok(SignalType::Str),
+        "tri1"       => {Ok(SigType::Tri1)}
-        "supply0" => Ok(SignalType::Supply0),
+        "time"       => {Ok(SigType::Time)}
-        "supply1" => Ok(SignalType::Supply1),
-        "tri" => Ok(SignalType::Tri),
-        "triand" => Ok(SignalType::TriAnd),
-        "trior" => Ok(SignalType::TriOr),
-        "trireg" => Ok(SignalType::TriReg),
-        "tri0" => Ok(SignalType::Tri0),
-        "tri1" => Ok(SignalType::Tri1),
-        "time" => Ok(SignalType::Time),
-        "wand" => Ok(SignalType::WAnd),
-        "wire" => Ok(SignalType::Wire),
-        "wor" => Ok(SignalType::WOr),
         _ => {
-            let err = format!(
+            let err = format!("Error near {}:{} \
-                "Error near {}:{} \
                                found keyword `{word}` but expected one of \
-                               {expected_types:?} on {cursor:?}",
+                               {expected_types:?} on {cursor:?}", file!(), line!());
-                file!(),
-                line!()
-            );
             Err(err)
         }
     }?;
 
-    let (word, cursor) = next_word!(word_reader)?;
+    let (word, cursor) = word_reader.next_word()?;
-
     let parse_err = format!("failed to parse as usize on {cursor:?}");
 
     // $var parameter 3 a IDLE $end
-    //                ^ - num_bits
+    //                ^ - no_bits
-    let num_bits = match var_type {
+    let no_bits = match var_type {
-        SignalType::Event
+        SigType::Integer | SigType::Parameter |
-        | SignalType::Integer
+        SigType::Real    | SigType::Reg       |
-        | SignalType::Parameter
+        SigType::Wire    | SigType::Tri1      |
-        | SignalType::Reg
+        SigType::Time => {
-        | SignalType::Supply0
+            let no_bits = word.parse::<usize>().expect(parse_err.as_str());
-        | SignalType::Supply1
+            Some(no_bits)
-        | SignalType::Tri
-        | SignalType::TriAnd
-        | SignalType::TriOr
-        | SignalType::TriReg
-        | SignalType::Tri0
-        | SignalType::Tri1
-        | SignalType::Time
-        | SignalType::WAnd
-        | SignalType::Wire
-        | SignalType::WOr => {
-            let num_bits = word
-                .parse::<usize>()
-                .unwrap_or_else(|_| panic!("{}", parse_err));
-            let num_bits = u32::try_from(num_bits).map_err(|_| {
-                format!(
-                    "Error near {}:{} while parsing vcd file at {cursor:?}. \
-                     This signal has {num_bits} > 2^32 - 1 bits.",
-                    file!(),
-                    line!()
-                )
-            })?;
-            Some(num_bits)
         }
-        // for strings, reals, and realtimes we don't really care what the number of bits is
+        // for strings, we don't really care what the number of bits is
-        _ => None,
+        _ => {None}
     };
 
     // $var parameter 3 a IDLE $end
     //                  ^ - signal_alias
-    let (word, _) = next_word!(word_reader)?;
+    let (word, _) = word_reader.next_word()?;
     let signal_alias = word.to_string();
 
     // $var parameter 3 a IDLE $end
     //                    ^^^^ - full_signal_name(can extend until $end)
     let mut full_signal_name = Vec::<String>::new();
-    let mut size = None;
     loop {
-        let (word, _) = next_word!(word_reader)?;
+        let (word, _) = word_reader.next_word()?;
         match word {
-            "$end" => break,
+            "$end" => {break}
-            other if other.starts_with('[') => size = Some(other.to_string()),
+            _      => {full_signal_name.push(word.to_string())}
-            _ => full_signal_name.push(word.to_string()),
         }
     }
     let full_signal_name = full_signal_name.join(" ");
 
-    let num_bytes = if num_bits.is_some() {
-        let bytes_required = SignalEnum::bytes_required(num_bits.unwrap(), &full_signal_name)?;
-        Some(bytes_required)
-    } else {
-        None
-    };
-
     // Is the current variable an alias to a signal already encountered?
     // if so, handle ref_signal_idx accordingly, if not, add signal to hash
     // map
     let (signal, signal_idx) = match signal_map.get(&signal_alias) {
         Some(ref_signal_idx) => {
             let signal_idx = SignalIdx(vcd.all_signals.len());
-            let signal = SignalEnum::Alias {
+            let signal = Signal::Alias{
-                name: full_signal_name.clone(),
+                name: full_signal_name,
-                path: path
+                signal_alias: *ref_signal_idx};
-                    .iter()
-                    .cloned()
-                    .chain([full_signal_name])
-                    .collect::<Vec<String>>(),
-                signal_alias: *ref_signal_idx,
-            };
             (signal, signal_idx)
         }
         None => {
             let signal_idx = SignalIdx(vcd.all_signals.len());
             signal_map.insert(signal_alias.to_string(), signal_idx);
-            let signal = SignalEnum::Data {
+            let signal = Signal::Data{
-                name: full_signal_name.clone(),
+                name: full_signal_name,
-                path: path
+                sig_type: var_type,
-                    .iter()
-                    .cloned()
-                    .chain([full_signal_name])
-                    .collect::<Vec<String>>(),
-                signal_type: var_type,
-                index: size,
                 signal_error: None,
-                num_bits,
+                num_bits: no_bits,
-                num_bytes,
                 self_idx: signal_idx,
-                nums_encoded_as_fixed_width_le_u8: vec![],
+                u8_timeline: vec![],
-                string_vals: vec![],
+                u8_timeline_markers: vec![],
-                lsb_indxs_of_num_tmstmp_vals_on_tmln: vec![],
+                string_timeline: vec![],
-                byte_len_of_num_tmstmp_vals_on_tmln: vec![],
+                string_timeline_markers: vec![],
-                byte_len_of_string_tmstmp_vals_on_tmln: vec![],
+                scope_parent: parent_scope_idx };
-                lsb_indxs_of_string_tmstmp_vals_on_tmln: vec![],
-            };
             (signal, signal_idx)
         }
     };
@@ -198,10 +103,10 @@ pub(super) fn parse_var<R: std::io::Read>(
 
 /// Sometimes, variables can be listed outside of scopes.
 /// We call these orphaned vars.
-fn parse_orphaned_vars<R: std::io::Read>(
+fn parse_orphaned_vars<'a>(
-    word_reader: &mut WordReader<R>,
+    word_reader      : &mut WordReader,
-    vcd: &mut VCD,
+    vcd              : &'a mut VCD,
-    signal_map: &mut HashMap<String, SignalIdx>,
+    signal_map       : &mut HashMap<String, SignalIdx>
 ) -> Result<(), String> {
     // create scope for unscoped signals if such a scope does not
     // yet exist
@@ -219,40 +124,39 @@ fn parse_orphaned_vars<R: std::io::Read>(
         if scope.name == scope_name {
             scope_idx = scope.self_idx;
             scope_already_exists = true;
-            break;
+            break
         }
     }
 
     if !scope_already_exists {
-        vcd.all_scopes.push(Scope {
+        vcd.all_scopes.push(
+            Scope {
                 name: scope_name.to_string(),
+                parent_idx: None,
                 self_idx: scope_idx,
                 child_signals: vec![],
-            child_scopes: vec![],
+                child_scopes: vec![]
-        });
+            }
-        vcd.root_scopes.push(scope_idx);
+        );
+        vcd.scope_roots.push(scope_idx);
     }
     
     // we can go ahead and parse the current var as we've already encountered
     // "$var" before now.
-    parse_var(word_reader, scope_idx, vcd, signal_map, &vec![])?;
+    parse_var(word_reader, scope_idx, vcd, signal_map)?;
 
     loop {
-        let (word, cursor) = next_word!(word_reader)?;
+        let (word, cursor) = word_reader.next_word()?;
 
         match word {
             "$var" => {
-                parse_var(word_reader, scope_idx, vcd, signal_map, &vec![])?;
+                parse_var(word_reader, scope_idx, vcd, signal_map)?;
             }
-            "$scope" => break,
+            "$scope" => {break}
             _ => {
-                let msg = format!(
+                let msg = format!("Error near {}:{}.\
-                    "Error near {}:{}.\
                           Expected $scope or $var, found \
-                          {word} at {cursor:?}",
+                          {word} at {cursor:?}", file!(), line!());
-                    file!(),
-                    line!()
-                );
                 Err(msg)?;
             }
         };
@@ -261,40 +165,30 @@ fn parse_orphaned_vars<R: std::io::Read>(
     Ok(())
 }
 
-fn parse_scopes_inner<R: std::io::Read>(
+pub(super) fn parse_signal_tree<'a>(
-    word_reader: &mut WordReader<R>,
+    word_reader      : &mut WordReader,
     parent_scope_idx : Option<ScopeIdx>,
-    vcd: &mut VCD,
+    vcd              : &'a mut VCD,
-    signal_map: &mut HashMap<String, SignalIdx>,
+    signal_map       : &mut HashMap<String, SignalIdx>
-    path: &Vec<String>,
 ) -> Result<(), String> {
+
     // $scope module reg_mag_i $end
     //        ^^^^^^ - module keyword
-    let (keyword, cursor) = next_word!(word_reader)?;
+    let (keyword, cursor) = word_reader.next_word()?;
 
-    let expected = ["module", "begin", "task", "function", "fork"];
+    let expected = ["module", "begin", "task", "function"];
     if expected.contains(&keyword) {
         Ok(())
     } else {
-        let err = format!(
+        let err = format!("Error near {}:{}. \
-            "Error near {}:{}. \
                             found keyword `{keyword}` but expected one of \
-                            {expected:?} on {cursor:?}",
+                            {expected:?} on {cursor:?}", file!(), line!());
-            file!(),
-            line!()
-        );
         Err(err)
     }?;
 
     // $scope module reg_mag_i $end
     //               ^^^^^^^^^ - scope name
-    let (scope_name, _) = next_word!(word_reader)?;
+    let (scope_name, _) = word_reader.next_word()?;
-    // In some cases there are VCD files which have scopes without names.
-    // since these occur in the wild, we'll tolerate them even if it is unclear
-    // if it is supported or not by the spec.
-    if scope_name != "$end" {
-        let mut path = path.clone();
-        path.push(scope_name.to_string());
 
     let curr_scope_idx = ScopeIdx(vcd.all_scopes.len());
     
@@ -306,23 +200,28 @@ fn parse_scopes_inner<R: std::io::Read>(
             let parent_scope = vcd.all_scopes.get_mut(parent_scope_idx).unwrap();
             parent_scope.child_scopes.push(curr_scope_idx);
         }
-            None => vcd.root_scopes.push(curr_scope_idx),
+        None => {
+            vcd.scope_roots.push(curr_scope_idx)
+        }
     }
 
     // add this scope to list of existing scopes
-        vcd.all_scopes.push(Scope {
+    vcd.all_scopes.push(
+        Scope {
             name: scope_name.to_string(),
+            parent_idx: parent_scope_idx,
             self_idx: curr_scope_idx,
             child_signals: vec![],
-            child_scopes: vec![],
+            child_scopes: vec![]
-        });
+        }
+    );
 
     // $scope module reg_mag_i $end
     //                         ^^^^ - end keyword
     ident(word_reader, "$end")?;
 
     loop {
-            let (word, cursor) = next_word!(word_reader)?;
+        let (word, cursor) = word_reader.next_word()?;
         let ParseResult{matched, residual} = tag(word, "$");
         match matched {
             // we hope that this word starts with a `$`
@@ -330,113 +229,35 @@ fn parse_scopes_inner<R: std::io::Read>(
                 match residual {
                     "scope" => {
                         // recursive - parse inside of current scope tree
-                            parse_scopes_inner(
+                        parse_signal_tree(word_reader, Some(curr_scope_idx), vcd, signal_map)?;
-                                word_reader,
-                                Some(curr_scope_idx),
-                                vcd,
-                                signal_map,
-                                &path,
-                            )?;
                     }
                     "var" => {
-                            parse_var(word_reader, curr_scope_idx, vcd, signal_map, &path)?;
+                        parse_var(word_reader, curr_scope_idx, vcd, signal_map)?;
                     }
                     "upscope" => {
                         ident(word_reader, "$end")?;
-                            break;
+                        break
                     }
                     // we ignore comments
-                        "comment" => loop {
+                    "comment" => {
-                            if ident(word_reader, "$end").is_ok() {
+                        loop {
-                                break;
+                            if ident(word_reader, "$end").is_ok() {break}
+                        }
                     }
-                        },
                     _ => {
-                            let err = format!(
+                        let err = format!("Error near {}:{}. \
-                                "Error near {}:{}. \
                                            found keyword `{residual}` but expected \
                                            `$scope`, `$var`, `$comment`, or `$upscope` \
-                                               on {cursor:?}",
+                                           on {cursor:?}", file!(), line!());
-                                file!(),
+                        return Err(err)
-                                line!()
-                            );
-                            return Err(err);
                     }
                 }
             }
             _ => {
-                    let err = format!(
+                let err = format!("Error near {}:{}. \
-                        "Error near {}:{}. \
                                   found keyword `{matched}` but \
-                                      expected `$` on {cursor:?}",
+                                  expected `$` on {cursor:?}", file!(), line!());
-                        file!(),
+                return Err(err)
-                        line!()
-                    );
-                    return Err(err);
-                }
-            }
-        }
-    } else {
-        // We'll be conservative and only allow new scopes in this case, and make the nameless
-        // scope completely transparent. I.e.
-        // $scope module a $end
-        //   $scope module $end
-        //     $scope module b $end
-        //       ...
-        //     $upscope
-        //   $upscope
-        // $upscope
-        // will create `a.b`
-        loop {
-            let (word, cursor) = next_word!(word_reader)?;
-            let ParseResult { matched, residual } = tag(word, "$");
-            match matched {
-                // we hope that this word starts with a `$`
-                "$" => {
-                    match residual {
-                        "scope" => {
-                            // recursive - parse inside of current scope tree
-                            parse_scopes_inner(
-                                word_reader,
-                                parent_scope_idx,
-                                vcd,
-                                signal_map,
-                                &path,
-                            )?;
-                        }
-                        "upscope" => {
-                            ident(word_reader, "$end")?;
-                            break;
-                        }
-                        // we ignore comments
-                        "comment" => loop {
-                            if ident(word_reader, "$end").is_ok() {
-                                break;
-                            }
-                        },
-                        _ => {
-                            let err = format!(
-                                "Error near {}:{}. \
-                                               found keyword `{residual}` in annonyoums scope but expected \
-                                               `$scope`, `$comment`, or `$upscope` \
-                                               on {cursor:?}",
-                                file!(),
-                                line!()
-                            );
-                            return Err(err);
-                        }
-                    }
-                }
-                _ => {
-                    let err = format!(
-                        "Error near {}:{}. \
-                                      found keyword `{matched}` but \
-                                      expected `$` on {cursor:?}",
-                        file!(),
-                        line!()
-                    );
-                    return Err(err);
-                }
             }
         }
     }
@@ -444,13 +265,13 @@ fn parse_scopes_inner<R: std::io::Read>(
     Ok(())
 }
 
-pub(super) fn parse_scopes<R: std::io::Read>(
+pub(super) fn parse_scopes<'a>(
-    word_reader: &mut WordReader<R>,
+    word_reader      : &mut WordReader,
-    vcd: &mut VCD,
+    vcd              : &'a mut VCD,
-    signal_map: &mut HashMap<String, SignalIdx>,
+    signal_map       : &mut HashMap<String, SignalIdx>
 ) -> Result<(), String> {
     // get the current word
-    let (word, _) = curr_word!(word_reader)?;
+    let (word, _) = word_reader.curr_word()?;
 
     // we may have orphaned vars that occur before the first scope
     if word == "$var" {
@@ -458,62 +279,52 @@ pub(super) fn parse_scopes<R: std::io::Read>(
     } 
     
     // get the current word
-    let (word, cursor) = curr_word!(word_reader)?;
+    let (word, cursor) = word_reader.curr_word()?;
 
     // the current word should be "scope", as `parse_orphaned_vars`(if it
     // was called), should have terminated upon encountering "$scope".
     // If `parse_orphaned_vars` was not called, `parse_scopes` should still
     // have only been called if the caller encountered the word "$scope"
     if word != "$scope" {
-        let msg = format!(
+        let msg = format!("Error near {}:{}.\
-            "Error near {}:{}.\
                            Expected $scope or $var, found \
-                           {word} at {cursor:?}",
+                           {word} at {cursor:?}", file!(), line!());
-            file!(),
+        return Err(msg)
-            line!()
-        );
-        return Err(msg);
     }
 
     // now for the interesting part
-    parse_scopes_inner(word_reader, None, vcd, signal_map, &vec![])?;
+    parse_signal_tree(word_reader, None, vcd, signal_map)?;
 
     // let err = format!("reached end of file without parser leaving {}", function_name!());
     let expected_keywords = ["$scope", "$enddefinitions"];
 
     // there could be multiple signal trees, and unfortunately, we
-    // can't merge the earlier call to `parse_scopes_inner` into this loop
+    // can't merge the earlier call to `parse_signal_tree` into this loop
     // because this loop gets a word from `next_word` instead of 
     // `curr_word()`.
     loop {
-        let (word, cursor) = next_word!(word_reader)?;
+        let (word, cursor) = word_reader.next_word()?;
-
         match word {
             "$scope" => {
-                parse_scopes_inner(word_reader, None, vcd, signal_map, &vec![])?;
+                parse_signal_tree(word_reader, None, vcd, signal_map)?;
             }
             "$enddefinitions" => {
                 ident(word_reader, "$end")?;
-                break;
+                break
             }
-            "$comment" => {
+            "comment" => {
                 // although we don't store comments, we still need to advance the
                 // word_reader cursor to the end of the comment
                 loop {
-                    if ident(word_reader, "$end").is_ok() {
+                    if ident(word_reader, "$end").is_ok() {break}
-                        break;
-                    }
                 }
             }
             _ => {
-                let err = format!(
+                let err = format!("Error near {}:{} \
-                    "Error near {}:{} \
                                 found keyword `{word}` but expected one of \
-                                {expected_keywords:?} on {cursor:?}",
+                                {expected_keywords:?} on {cursor:?}", file!(), line!());
-                    file!(),
+                return Err(err)
-                    line!()
+    
-                );
-                return Err(err);
             }
         }
     }

src/vcd/parse/types.rs

@@ -1,27 +1,25 @@
-// Copyright (C) 2022 Yehowshua Immanuel
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
 #[derive(Debug)]
 pub(super) struct ParseResult<'a> {
     pub(super) matched : &'a str, 
-    pub(super) residual: &'a str,
+    pub(super) residual : &'a str}
-}
 
 impl<'a> ParseResult<'a> {
+
     pub(super) fn assert_match(& self) -> Result<&str, String> {
-        if self.matched.is_empty() {
+        if self.matched == "" {
-            Err("no match".to_string())
+            return Err("no match".to_string())
-        } else {
+        }
-            Ok(self.matched)
+        else {
+            return Ok(self.matched)
         }
     }
 
     pub(super) fn assert_residual(& self) -> Result<&str, String> {
-        if self.residual.is_empty() {
+        if self.residual == "" {
-            Err("no residual".to_string())
+            return Err("no residual".to_string())
-        } else {
+        }
-            Ok(self.residual)
+        else {
+            return Ok(self.residual)
         }
     }
 }

src/vcd/reader.rs

@@ -1,22 +1,25 @@
-// Copyright (C) 2022 Yehowshua Immanuel
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
 use std::collections::VecDeque;
+use std::fs::File;
 use std::io;
-use std::io::BufRead;
+use std::io::prelude::*;
 use std::slice;
 use std::str;
 
+use backtrace::{Backtrace, BacktraceFrame, BacktraceSymbol};
+
 #[derive(Debug, Clone)]
 pub(super) struct Line(pub(super) usize);
 #[derive(Debug, Clone)]
 pub(super) struct Word(pub(super) usize);
 #[derive(Debug, Clone)]
 pub(super) struct Cursor(pub(super) Line, pub(super) Word);
+#[derive(Debug)]
+pub(super) enum FileStatus {
+    Eof,
+}
 
-pub(super) struct WordReader<R: io::Read> {
+pub struct WordReader {
-    reader: io::BufReader<R>,
+    reader: io::BufReader<File>,
     eof: bool,
     buffers: Vec<String>,
     curr_line: usize,
@@ -24,11 +27,11 @@ pub(super) struct WordReader<R: io::Read> {
     curr_slice: Option<(*const u8, usize, Cursor)>,
 }
 
-impl<R: std::io::Read> WordReader<R> {
+impl WordReader {
-    pub(super) fn new(file: R) -> WordReader<R> {
+    pub(super) fn new(file: File) -> WordReader {
         let reader = io::BufReader::new(file);
         WordReader {
-            reader,
+            reader: reader,
             eof: false,
             buffers: vec![],
             curr_line: 0,
@@ -37,7 +40,7 @@ impl<R: std::io::Read> WordReader<R> {
         }
     }
 
-    pub(super) fn next_word(&mut self) -> Option<(&str, Cursor)> {
+    pub(super) fn next_word(&mut self) -> Result<(&str, Cursor), FileStatus> {
         // although reaching the eof is not technically an error, in most cases,
         // we treat it like one in the rest of the codebase.
 
@@ -47,7 +50,7 @@ impl<R: std::io::Read> WordReader<R> {
             self.buffers.clear();
 
             if self.eof {
-                return None;
+                return Err(FileStatus::Eof);
             }
 
             let num_buffers = 10;
@@ -78,7 +81,7 @@ impl<R: std::io::Read> WordReader<R> {
         // if after we've attempted to read in more content from the file,
         // there are still no words...
         if self.str_slices.is_empty() {
-            return None;
+            return Err(FileStatus::Eof);
         }
 
         // if we make it here, we return the next word
@@ -86,46 +89,57 @@ impl<R: std::io::Read> WordReader<R> {
             let (ptr, len, position) = self.str_slices.pop_front().unwrap();
             let slice = slice::from_raw_parts(ptr, len);
             self.curr_slice = Some((ptr, len, position.clone()));
-            return Some((str::from_utf8(slice).unwrap(), position));
+            return Ok((str::from_utf8(slice).unwrap(), position));
         };
     }
 
-    pub(super) fn curr_word(&mut self) -> Option<(&str, Cursor)> {
+    pub(super) fn curr_word(&mut self) -> Result<(&str, Cursor), FileStatus> {
         match &self.curr_slice {
             Some(slice) => unsafe {
                 let (ptr, len, position) = slice.clone();
                 let slice = slice::from_raw_parts(ptr, len);
-                return Some((str::from_utf8(slice).unwrap(), position));
+                Ok((str::from_utf8(slice).unwrap(), position))
             },
-            None => None,
+            None => Err(FileStatus::Eof),
         }
     }
 }
 
-macro_rules! next_word {
+fn previous_symbol(level: u32) -> Option<BacktraceSymbol> {
-    ($word_reader:ident) => {
+    let (trace, curr_file, curr_line) = (Backtrace::new(), file!(), line!());
-        $word_reader.next_word().ok_or(()).map_err(|_| {
+    let frames = trace.frames();
-            format!(
+    frames
-                "Error near {}:{}. Did not expect to reach end of file here.",
+        .iter()
-                file!(),
+        .flat_map(BacktraceFrame::symbols)
-                line!()
+        .skip_while(|s| {
-            )
+            s.filename()
+                .map(|p| !p.ends_with(curr_file))
+                .unwrap_or(true)
+                || s.lineno() != Some(curr_line)
         })
-    };
+        .nth(1 + level as usize)
+        .cloned()
 }
 
-macro_rules! curr_word {
+impl From<FileStatus> for String {
-    ($word_reader:ident) => {
+    fn from(f: FileStatus) -> String {
-        $word_reader.curr_word().ok_or(()).map_err(|_| {
+        let sym = previous_symbol(1);
-            format!(
+        let filename = sym
-                "Error near {}:{}. A call to curr_word! shouldn't \
+            .as_ref()
-                 fail unless next_word has not yet been invoked.",
+            .and_then(BacktraceSymbol::filename)
-                file!(),
+            .map_or(None, |path| path.to_str())
-                line!()
+            .unwrap_or("(Couldn't determine filename)");
-            )
+        let lineno = sym
-        })
+            .as_ref()
-    };
+            .and_then(BacktraceSymbol::lineno)
-}
+            .map_or(None, |path| Some(path.to_string()))
+            .unwrap_or("(Couldn't determine line number)".to_string());
 
-pub(super) use curr_word;
+        match f {
-pub(super) use next_word;
+            FileStatus::Eof => format!(
+                "Error near {filename}:{lineno} \
+                 No more words left in vcd file."
+            ),
+        }
+    }
+}

src/vcd/signal.rs

@@ -1,715 +0,0 @@
-// Copyright (C) 2022 Yehowshua Immanuel
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
-use super::types;
-use super::types::SignalIdx;
-use num::BigUint;
-
-// Index to the least significant byte of a timestamp
-// value on the timeline
-#[derive(Debug, Copy, Clone)]
-pub struct LsbIdxOfTmstmpValOnTmln(pub(super) u32);
-
-#[derive(Debug, Eq, PartialEq, Clone)]
-pub enum SignalType {
-    Event,
-    Integer,
-    Parameter,
-    Real,
-    RealTime,
-    Reg,
-    Str,
-    Supply0,
-    Supply1,
-    Time,
-    Tri,
-    TriAnd,
-    TriOr,
-    TriReg,
-    Tri0,
-    Tri1,
-    WAnd,
-    Wire,
-    WOr,
-}
-
-#[derive(Debug, PartialEq)]
-pub enum SignalValue {
-    BigUint(BigUint),
-    String(String),
-}
-
-pub struct QueryResult<T> {
-    pub current: Option<(TimeStamp, T)>,
-    pub next: Option<TimeStamp>,
-}
-
-pub struct Signal<'a>(pub(super) &'a SignalEnum);
-
-impl<'a> Signal<'a> {
-    pub fn name(&self) -> String {
-        let Signal(signal_enum) = &self;
-        signal_enum.name()
-    }
-
-    pub fn name_with_index(&self) -> String {
-        let Signal(signal_enum) = &self;
-        signal_enum.name_with_index()
-    }
-
-    pub fn index(&self) -> Option<String> {
-        let Signal(signal_enum) = &self;
-        signal_enum.index()
-    }
-
-    pub fn path(&self) -> &[String] {
-        match self.0 {
-            SignalEnum::Data { path, .. } => path,
-            SignalEnum::Alias { path, .. } => path,
-        }
-    }
-
-    pub fn signal_type(&self) -> Option<&SignalType> {
-        let Signal(signal_enum) = &self;
-        signal_enum.signal_type()
-    }
-
-    pub fn real_idx(&self) -> SignalIdx {
-        match self.0 {
-            SignalEnum::Data { self_idx, .. } => *self_idx,
-            SignalEnum::Alias { signal_alias, .. } => *signal_alias,
-        }
-    }
-
-    pub fn num_bits(&self) -> Option<u32> {
-        let Signal(signal_enum) = &self;
-        signal_enum.bits_required()
-    }
-
-    // NOTE: (zoq) I am removing thse because they aren't used in Surfer so I can't test them
-    // properly
-    /*
-    pub fn query_string_val_on_tmln(
-        &self,
-        desired_time: &BigUint,
-        vcd: &types::VCD,
-    ) -> Result<String, SignalErrors> {
-        let Signal(signal_enum) = &self;
-        signal_enum
-            .query_string_val_on_tmln(desired_time, &vcd.tmstmps_encoded_as_u8s, &vcd.all_signals)
-            .map(|QueryResult{current, next: _}| current.map(|c| c.1))
-    }
-
-    pub fn query_num_val_on_tmln(
-        &self,
-        desired_time: &BigUint,
-        vcd: &types::VCD,
-    ) -> Result<Option<BigUint>, SignalErrors> {
-        let Signal(signal_enum) = &self;
-        signal_enum
-            .query_num_val_on_tmln(desired_time, &vcd.tmstmps_encoded_as_u8s, &vcd.all_signals)
-            .map(|QueryResult{current, next: _}| current.map(|c| c.1))
-    }
-    */
-
-    pub fn query_val_on_tmln(
-        &self,
-        desired_time: &BigUint,
-        vcd: &types::VCD,
-    ) -> Result<QueryResult<SignalValue>, SignalErrors> {
-        let Signal(signal_enum) = &self;
-        let num_query_out = signal_enum.query_num_val_on_tmln(
-            desired_time,
-            &vcd.tmstmps_encoded_as_u8s,
-            &vcd.all_signals,
-        );
-        let str_query_out = signal_enum.query_string_val_on_tmln(
-            desired_time,
-            &vcd.tmstmps_encoded_as_u8s,
-            &vcd.all_signals,
-        );
-
-        // Both num and str will return the newest value that is closest to
-        // the desired time. If both have valid values, select the most recent
-        // one
-        match (num_query_out, str_query_out) {
-            (Ok(num_result), Ok(str_result)) => {
-                let next = match (num_result.next, str_result.next) {
-                    (Some(n), Some(s)) => Some(n.min(s)),
-                    (Some(n), None) => Some(n),
-                    (None, Some(s)) => Some(s),
-                    (None, None) => None,
-                };
-
-                match (num_result.current, str_result.current) {
-                    (Some((num_time, num_value)), Some((str_time, str_value))) => {
-                        if num_time > str_time {
-                            Ok(QueryResult {
-                                current: Some((num_time, SignalValue::BigUint(num_value))),
-                                next,
-                            })
-                        } else {
-                            Ok(QueryResult {
-                                current: Some((str_time, SignalValue::String(str_value))),
-                                next,
-                            })
-                        }
-                    }
-                    (Some((num_time, num_val)), None) => Ok(QueryResult {
-                        current: Some((num_time, SignalValue::BigUint(num_val))),
-                        next,
-                    }),
-                    (None, Some((str_time, str_value))) => Ok(QueryResult {
-                        current: Some((str_time, SignalValue::String(str_value))),
-                        next,
-                    }),
-                    (None, None) => Ok(QueryResult {
-                        current: None,
-                        next,
-                    }),
-                }
-            }
-            (_e, Err(e)) => Err(e),
-            (Err(e), _e) => Err(e),
-        }
-    }
-}
-
-#[derive(Debug)]
-pub(super) enum SignalEnum {
-    Data {
-        name: String,
-        path: Vec<String>,
-        signal_type: SignalType,
-        /// The optional [start:end] part of the signal name that is sometimes
-        /// added to signals
-        index: Option<String>,
-        /// I've seen a 0 bit signal parameter in a xilinx
-        /// simulation before that gets assigned 1 bit values.
-        /// I consider this to be bad behavior. We capture such
-        /// errors in the following type:
-        signal_error: Option<String>,
-        num_bits: Option<u32>,
-        num_bytes: Option<u16>,
-        /// TODO : may be able to remove self_idx
-        self_idx: SignalIdx,
-        /// A signal may take on a new value and hold that value
-        /// for sometime. We only need to record the value of a signal
-        /// when it changes(the is what VCDs tend to do).
-        /// A signal may need x amount of bytes to record its largest
-        /// possible value, so we record every single value of a given
-        /// signal as a sequence of x number of u8s.
-        /// For example, we might find that `my_signal.
-        /// nums_encoded_as_fixed_width_le_u8`
-        /// has two 32 bit values, namely, 1 and 2, encoded as follows:
-        /// my_signal.nums_encoded_as_fixed_width_le_u8 = vec![1u8, 0u8,
-        /// 0u8, 0u8, 2u8, 0u8, 0u8, 0u8];
-        nums_encoded_as_fixed_width_le_u8: Vec<u8>,
-        string_vals: Vec<String>,
-        /// we could do Vec<(LsbIdxOfTmstmpValOnTmln, u8)>, but I
-        /// suspect that Vec<LsbIdxOfTmstmpValOnTmln> is more cache
-        /// friendly. We use ``LsbIdxOfTmstmpValOnTmln`` to index into
-        /// the LSB of a particular timestamp encoded as the
-        /// minimum length u8 sequence within
-        /// ``vcd.tmstmps_encoded_as_u8s``, and we use the values in
-        /// ``byte_len_of_num_tmstmp_vals_on_tmln`` to determine how
-        /// many u8 values a particular timestamp is composed of.
-        lsb_indxs_of_num_tmstmp_vals_on_tmln: Vec<LsbIdxOfTmstmpValOnTmln>,
-        byte_len_of_num_tmstmp_vals_on_tmln: Vec<u8>,
-        byte_len_of_string_tmstmp_vals_on_tmln: Vec<u8>,
-        lsb_indxs_of_string_tmstmp_vals_on_tmln: Vec<LsbIdxOfTmstmpValOnTmln>,
-    },
-    Alias {
-        name: String,
-        path: Vec<String>,
-        signal_alias: SignalIdx,
-    },
-}
-
-#[derive(Debug)]
-pub enum SignalErrors {
-    EmptyTimeline,
-    TimelineNotMultiple,
-    StrTmlnLenMismatch,
-    OrderingFailure {
-        lhs_time: BigUint,
-        mid_time: BigUint,
-        rhs_time: BigUint,
-    },
-    PointsToAlias,
-    NoNumBytes,
-    Other(String),
-}
-
-// these are thin type aliases primarily to make code more readable later on
-type TimeStamp = BigUint;
-type SignalValNum = BigUint;
-
-// getter functions
-impl SignalEnum {
-    pub fn name(&self) -> String {
-        match self {
-            SignalEnum::Data { name, .. } => name,
-            SignalEnum::Alias { name, .. } => name,
-        }
-        .clone()
-    }
-
-    pub fn signal_type(&self) -> Option<&SignalType> {
-        match self {
-            SignalEnum::Data { signal_type, .. } => Some(signal_type),
-            // TODO: Follow aliases?
-            SignalEnum::Alias { .. } => None,
-        }
-        .clone()
-    }
-
-    pub fn name_with_index(&self) -> String {
-        match self {
-            SignalEnum::Data {
-                name, index: None, ..
-            } => format!("{name}"),
-            SignalEnum::Data {
-                name,
-                index: Some(size),
-                ..
-            } => format!("{name} {size}"),
-            SignalEnum::Alias { name, .. } => name.clone(),
-        }
-    }
-
-    pub fn index(&self) -> Option<String> {
-        match self {
-            SignalEnum::Data { index, .. } => index.clone(),
-            SignalEnum::Alias { .. } => None,
-        }
-    }
-}
-
-// helper functions ultimately used by Signal's query functions later on
-impl SignalEnum {
-    /// Computes the bytes required to store a signal's numerical value
-    /// using the num_bits which another function would provide from
-    /// the num_bits field of the Signal::Data variant.
-    pub(super) fn bytes_required(num_bits: u32, name: &String) -> Result<u16, String> {
-        let bytes_required = (num_bits / 8) + if (num_bits % 8) > 0 { 1 } else { 0 };
-        let bytes_required = u16::try_from(bytes_required).map_err(|_| {
-            format!(
-                "Error near {}:{}. Signal {name} of length num_bits requires \
-                        {bytes_required} > 65536 bytes.",
-                file!(),
-                line!()
-            )
-        })?;
-        Ok(bytes_required)
-    }
-    /// This function takes an event_idx which(is used to index into the
-    /// global timeline field of a VCD struct instance) and computes
-    /// the time pointed at by event_idx.
-    /// This function also uses the same idx to index into the
-    /// string_vals field of an instance of the Signal::Data variant
-    ///  and gets a string value.
-    /// The function returns a tuple of the timestamp and string value.
-    fn time_and_str_val_at_event_idx(
-        &self,
-        event_idx: usize,
-        tmstmps_encoded_as_u8s: &Vec<u8>,
-    ) -> Result<(TimeStamp, &str), SignalErrors> {
-        let (
-            string_vals,
-            lsb_indxs_of_string_tmstmp_vals_on_tmln,
-            byte_len_of_string_tmstmp_vals_on_tmln,
-        ) = match self {
-            SignalEnum::Data {
-                string_vals,
-                lsb_indxs_of_string_tmstmp_vals_on_tmln,
-                byte_len_of_string_tmstmp_vals_on_tmln,
-                ..
-            } => Ok((
-                string_vals,
-                lsb_indxs_of_string_tmstmp_vals_on_tmln,
-                byte_len_of_string_tmstmp_vals_on_tmln,
-            )),
-            SignalEnum::Alias { .. } => Err(SignalErrors::PointsToAlias),
-        }?;
-
-        // get index
-        let LsbIdxOfTmstmpValOnTmln(timestamp_idx) =
-            lsb_indxs_of_string_tmstmp_vals_on_tmln[event_idx];
-        let timestamp_idx = timestamp_idx as usize;
-
-        if byte_len_of_string_tmstmp_vals_on_tmln.is_empty() {
-            return Err(SignalErrors::EmptyTimeline);
-        }
-
-        // form timestamp
-        let byte_len = byte_len_of_string_tmstmp_vals_on_tmln[event_idx] as usize;
-        let timestamp = &tmstmps_encoded_as_u8s[timestamp_idx..(timestamp_idx + byte_len)];
-        let timestamp = BigUint::from_bytes_le(timestamp);
-
-        // get signal value
-        let signal_val = string_vals[event_idx].as_str();
-
-        Ok((timestamp, signal_val))
-    }
-    /// This function takes an event_idx which(is used to index into the
-    /// global timeline field of a VCD struct instance) and computes
-    /// the time pointed at by event_idx.
-    /// This function also uses the same idx to index into the
-    /// nums_encoded_as_fixed_width_le_u8 and
-    /// byte_len_of_num_tmstmp_vals_on_tmln fields of an instance
-    /// of the Signal::Data variant to compute the signal's corresponding
-    /// numerical value at the time pointed at by event_didx.
-    /// The function returns a tuple of the timestamp and numerical
-    /// value.
-    fn time_and_num_val_at_event_idx(
-        &self,
-        event_idx: usize,
-        tmstmps_encoded_as_u8s: &Vec<u8>,
-    ) -> Result<(TimeStamp, SignalValNum), SignalErrors> {
-        let (
-            num_bytes,
-            nums_encoded_as_fixed_width_le_u8,
-            lsb_indxs_of_num_tmstmp_vals_on_tmln,
-            byte_len_of_num_tmstmp_vals_on_tmln,
-        ) = match self {
-            SignalEnum::Data {
-                num_bytes,
-                nums_encoded_as_fixed_width_le_u8,
-                lsb_indxs_of_num_tmstmp_vals_on_tmln,
-                byte_len_of_num_tmstmp_vals_on_tmln,
-                ..
-            } => Ok((
-                num_bytes,
-                nums_encoded_as_fixed_width_le_u8,
-                lsb_indxs_of_num_tmstmp_vals_on_tmln,
-                byte_len_of_num_tmstmp_vals_on_tmln,
-            )),
-            SignalEnum::Alias { .. } => Err(SignalErrors::PointsToAlias),
-        }?;
-
-        // get index
-        let LsbIdxOfTmstmpValOnTmln(timestamp_idx) =
-            lsb_indxs_of_num_tmstmp_vals_on_tmln[event_idx];
-        let timestamp_idx = timestamp_idx as usize;
-
-        // form timestamp
-        let byte_len = byte_len_of_num_tmstmp_vals_on_tmln[event_idx] as usize;
-        let timestamp = &tmstmps_encoded_as_u8s[timestamp_idx..(timestamp_idx + byte_len)];
-        let timestamp = BigUint::from_bytes_le(timestamp);
-
-        // get signal value
-        let bytes_per_value = num_bytes.ok_or_else(|| SignalErrors::NoNumBytes)?;
-        let bytes_per_value = bytes_per_value as usize;
-        let start_idx = event_idx * bytes_per_value;
-        let end_idx = (event_idx + 1) * bytes_per_value;
-        let signal_val = &nums_encoded_as_fixed_width_le_u8[start_idx..end_idx];
-        let signal_val = BigUint::from_bytes_le(signal_val);
-
-        Ok((timestamp, signal_val))
-    }
-
-    fn bits_required(&self) -> Option<u32> {
-        match self {
-            SignalEnum::Data { num_bits, .. } => *num_bits,
-            // TODO: Follow aliases?
-            SignalEnum::Alias { .. } => None,
-        }
-    }
-}
-
-// Val and string query functions.
-// Function that take in a desired time on the timeline for a
-// specific signal and return a numerical or string value in a Result,
-// or an error in a Result.
-impl SignalEnum {
-    pub fn query_string_val_on_tmln(
-        &self,
-        desired_time: &BigUint,
-        tmstmps_encoded_as_u8s: &Vec<u8>,
-        all_signals: &Vec<SignalEnum>,
-    ) -> Result<QueryResult<String>, SignalErrors> {
-        let signal_idx = match self {
-            Self::Data { self_idx, .. } => {
-                let SignalIdx(idx) = self_idx;
-                *idx
-            }
-            Self::Alias {
-                name: _,
-                signal_alias,
-                path: _,
-            } => {
-                let SignalIdx(idx) = signal_alias;
-                *idx
-            }
-        };
-
-        // if the signal idx points to data variant of the signal,
-        // extract:
-        // 1. the vector of string values
-        // 2. the vector of indices into timeline where events occur
-        //    for this signal
-        // else we propagate Err(..).
-        let (string_vals, lsb_indxs_of_string_tmstmp_vals_on_tmln) = match &all_signals[signal_idx]
-        {
-            SignalEnum::Data {
-                ref string_vals,
-                ref lsb_indxs_of_string_tmstmp_vals_on_tmln,
-                ..
-            } => Ok((string_vals, lsb_indxs_of_string_tmstmp_vals_on_tmln)),
-            SignalEnum::Alias { .. } => Err(SignalErrors::PointsToAlias),
-        }?;
-        // this signal should at least have some events, otherwise, trying to index into
-        // an empty vector later on would fail
-        if lsb_indxs_of_string_tmstmp_vals_on_tmln.is_empty() {
-            return Ok(QueryResult {
-                current: None,
-                next: None
-            });
-        }
-
-        // the vector of string timeline lsb indices should have the same
-        // length as the vector of string values
-        if string_vals.len() != lsb_indxs_of_string_tmstmp_vals_on_tmln.len() {
-            return Err(SignalErrors::StrTmlnLenMismatch);
-        }
-
-        // check if we're requesting a value that occurs before the recorded
-        // start of the timeline
-        let (timeline_start_time, _) =
-            self.time_and_str_val_at_event_idx(0, tmstmps_encoded_as_u8s)?;
-        if *desired_time < timeline_start_time {
-            return Ok(QueryResult {
-                current: None,
-                next: Some(timeline_start_time),
-            });
-        }
-
-        let mut lower_idx = 0usize;
-        let mut upper_idx = lsb_indxs_of_string_tmstmp_vals_on_tmln.len() - 1;
-        let (timeline_end_time, timeline_end_val) =
-            self.time_and_str_val_at_event_idx(upper_idx, tmstmps_encoded_as_u8s)?;
-
-        // check if we're requesting a value that occurs beyond the end of the timeline,
-        // if so, return the last value in this timeline
-        if *desired_time > timeline_end_time {
-            return Ok(QueryResult {
-                current: Some((timeline_end_time, timeline_end_val.to_string())),
-                next: None,
-            });
-        }
-
-        // This while loop is the meat of the lookup. Performance is log2(n),
-        // where n is the number of events on the timeline.
-        // We can assume that by the time we get here, that the desired_time
-        // is an event that occurs on the timeline, given that we handle any events
-        // occuring after or before the recorded tiimeline in the code above.
-        while lower_idx <= upper_idx {
-            let mid_idx = lower_idx + ((upper_idx - lower_idx) / 2);
-            let (curr_time, curr_val) =
-                self.time_and_str_val_at_event_idx(mid_idx, tmstmps_encoded_as_u8s)?;
-            let ordering = curr_time.cmp(desired_time);
-
-            match ordering {
-                std::cmp::Ordering::Less => {
-                    lower_idx = mid_idx + 1;
-                }
-                std::cmp::Ordering::Equal => {
-                    let next_time = if mid_idx < lsb_indxs_of_string_tmstmp_vals_on_tmln.len() - 1 {
-                        Some(
-                            self.time_and_str_val_at_event_idx(
-                                mid_idx + 1,
-                                tmstmps_encoded_as_u8s,
-                            )?
-                            .0,
-                        )
-                    } else {
-                        None
-                    };
-                    return Ok(QueryResult {
-                        current: Some((curr_time, curr_val.to_string())),
-                        next: next_time,
-                    });
-                }
-                std::cmp::Ordering::Greater => {
-                    upper_idx = mid_idx - 1;
-                }
-            }
-        }
-
-        let (left_time, left_val) =
-            self.time_and_str_val_at_event_idx(lower_idx - 1, tmstmps_encoded_as_u8s)?;
-        let (right_time, _) =
-            self.time_and_str_val_at_event_idx(lower_idx, tmstmps_encoded_as_u8s)?;
-
-        let ordered_left = left_time < *desired_time;
-        let ordered_right = *desired_time < right_time;
-        if !(ordered_left && ordered_right) {
-            return Err(SignalErrors::OrderingFailure {
-                lhs_time: left_time,
-                mid_time: desired_time.clone(),
-                rhs_time: right_time,
-            });
-        }
-
-        Ok(QueryResult {
-            current: Some((left_time, left_val.to_string())),
-            next: Some(right_time),
-        })
-    }
-    pub fn query_num_val_on_tmln(
-        &self,
-        desired_time: &BigUint,
-        tmstmps_encoded_as_u8s: &Vec<u8>,
-        all_signals: &Vec<SignalEnum>,
-    ) -> Result<QueryResult<BigUint>, SignalErrors> {
-        let signal_idx = match self {
-            Self::Data { self_idx, .. } => {
-                let SignalIdx(idx) = self_idx;
-                *idx
-            }
-            Self::Alias {
-                name: _,
-                path: _,
-                signal_alias,
-            } => {
-                let SignalIdx(idx) = signal_alias;
-                *idx
-            }
-        };
-
-        // if the signal idx points to data variant of the signal,
-        // extract:
-        // 1. the vector of LE u8 compressed values
-        // 2. the vector of indices into timeline where events occur
-        //    for this signal
-        // 3. the number of bytes per value for this signal
-        // else we propagate Err(..).
-        let (nums_encoded_as_fixed_width_le_u8, lsb_indxs_of_num_tmstmp_vals_on_tmln, num_bytes) =
-            match &all_signals[signal_idx] {
-                SignalEnum::Data {
-                    num_bytes,
-                    ref nums_encoded_as_fixed_width_le_u8,
-                    ref lsb_indxs_of_num_tmstmp_vals_on_tmln,
-                    ..
-                } => {
-                    if num_bytes.is_none() {
-                        return Err(SignalErrors::NoNumBytes);
-                    }
-                    Ok((
-                        nums_encoded_as_fixed_width_le_u8,
-                        lsb_indxs_of_num_tmstmp_vals_on_tmln,
-                        num_bytes,
-                    ))
-                }
-                SignalEnum::Alias { .. } => Err(SignalErrors::PointsToAlias),
-            }?;
-        // this signal should at least have some events, otherwise, trying to index into
-        // an empty vector later on would fail
-        if lsb_indxs_of_num_tmstmp_vals_on_tmln.is_empty() {
-            return Ok(QueryResult {
-                current: None,
-                next: None
-            });
-        }
-
-        // assertion that value_sequence is a proper multiple of
-        // timeline_markers
-        let bytes_required = num_bytes.ok_or_else(|| {
-            SignalErrors::Other(format!(
-                "Error near {}:{}. num_bytes empty.",
-                file!(),
-                line!()
-            ))
-        })?;
-        if nums_encoded_as_fixed_width_le_u8.len()
-            != (lsb_indxs_of_num_tmstmp_vals_on_tmln.len() * (bytes_required as usize))
-        {
-            return Err(SignalErrors::TimelineNotMultiple);
-        }
-
-        // check if we're requesting a value that occurs before the recorded
-        // start of the timeline
-        let (timeline_start_time, _) =
-            self.time_and_num_val_at_event_idx(0, tmstmps_encoded_as_u8s)?;
-        if *desired_time < timeline_start_time {
-            return Ok(QueryResult {
-                current: None,
-                next: Some(timeline_start_time),
-            });
-        }
-
-        let mut lower_idx = 0usize;
-        let mut upper_idx = lsb_indxs_of_num_tmstmp_vals_on_tmln.len() - 1;
-        let (timeline_end_time, timeline_end_val) =
-            self.time_and_num_val_at_event_idx(upper_idx, tmstmps_encoded_as_u8s)?;
-
-        // check if we're requesting a value that occurs beyond the end of the timeline,
-        // if so, return the last value in this timeline
-        if *desired_time > timeline_end_time {
-            return Ok(QueryResult {
-                current: Some((timeline_end_time, timeline_end_val)),
-                next: None,
-            });
-        }
-
-        // This while loop is the meat of the lookup. Performance is log2(n),
-        // where n is the number of events on the timeline.
-        // We can assume that by the time we get here, that the desired_time
-        // is an event that occurs on the timeline, given that we handle any events
-        // occuring after or before the recorded tiimeline in the code above.
-        while lower_idx <= upper_idx {
-            let mid_idx = lower_idx + ((upper_idx - lower_idx) / 2);
-            let (curr_time, curr_val) =
-                self.time_and_num_val_at_event_idx(mid_idx, tmstmps_encoded_as_u8s)?;
-            let ordering = curr_time.cmp(desired_time);
-
-            match ordering {
-                std::cmp::Ordering::Less => {
-                    lower_idx = mid_idx + 1;
-                }
-                std::cmp::Ordering::Equal => {
-                    let next_time = if mid_idx < lsb_indxs_of_num_tmstmp_vals_on_tmln.len() - 1 {
-                        Some(
-                            self.time_and_num_val_at_event_idx(
-                                mid_idx + 1,
-                                tmstmps_encoded_as_u8s,
-                            )?
-                            .0,
-                        )
-                    } else {
-                        None
-                    };
-                    return Ok(QueryResult {
-                        current: Some((curr_time, curr_val)),
-                        next: next_time,
-                    });
-                }
-                std::cmp::Ordering::Greater => {
-                    upper_idx = mid_idx - 1;
-                }
-            }
-        }
-
-        let (left_time, left_val) =
-            self.time_and_num_val_at_event_idx(lower_idx - 1, tmstmps_encoded_as_u8s)?;
-        let (right_time, _) =
-            self.time_and_num_val_at_event_idx(lower_idx, tmstmps_encoded_as_u8s)?;
-
-        let ordered_left = left_time < *desired_time;
-        let ordered_right = *desired_time < right_time;
-        if !(ordered_left && ordered_right) {
-            return Err(SignalErrors::OrderingFailure {
-                lhs_time: left_time,
-                mid_time: desired_time.clone(),
-                rhs_time: right_time,
-            });
-        }
-
-        return Ok(QueryResult {
-            current: Some((left_time, left_val)),
-            next: Some(right_time),
-        });
-    }
-}

src/vcd/types.rs

@@ -1,19 +1,10 @@
-// use crate::Signal;
+use chrono::prelude::*;
 
-// Copyright (C) 2022 Yehowshua Immanuel
+#[derive(Debug)]
-// This program is distributed under both the GPLV3 license
+pub(super) struct Version(pub String);
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
-use super::signal::{Signal, SignalEnum};
-use chrono::prelude::{DateTime, Utc};
-use num::BigUint;
-use std::fmt;
 
-#[derive(Debug, Clone)]
+#[derive(Debug)]
-pub struct Version(pub String);
+pub(super) enum Timescale {
-
-#[derive(Debug, Clone, Copy, Eq, PartialEq)]
-pub enum Timescale {
     Fs,
     Ps,
     Ns,
@@ -23,122 +14,145 @@ pub enum Timescale {
     Unit,
 }
 
-impl fmt::Display for Timescale {
+#[derive(Debug)]
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+pub(super) struct Metadata {
-        match self {
+    pub(super) date: Option<DateTime<Utc>>,
-            Timescale::Fs => write!(f, "fs"),
+    pub(super) version: Option<Version>,
-            Timescale::Ps => write!(f, "ps"),
+    pub(super) timescale: (Option<u32>, Timescale),
-            Timescale::Ns => write!(f, "ns"),
-            Timescale::Us => write!(f, "μs"),
-            Timescale::Ms => write!(f, "ms"),
-            Timescale::S => write!(f, "s"),
-            Timescale::Unit => write!(f, "unit"),
-        }
 }
+
+#[derive(Debug, Copy, Clone)]
+pub(super) struct ScopeIdx(pub(super) usize);
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub(super) struct SignalIdx(pub(super) usize);
+
+#[derive(Debug, Copy, Clone)]
+pub(super) struct TimelineIdx(pub(super) u32);
+
+#[derive(Debug, Copy, Clone)]
+pub struct StartIdx(pub(super) u32);
+
+#[derive(Debug)]
+pub(super) enum SigType {
+    Integer,
+    Parameter,
+    Real,
+    Reg,
+    Str,
+    Wire,
+    Tri1,
+    Time,
 }
 
 #[derive(Debug)]
-pub struct Metadata {
+pub(super) enum Signal {
-    pub date: Option<DateTime<Utc>>,
+    Data {
-    pub version: Option<Version>,
+        name: String,
-    pub timescale: (Option<u32>, Timescale),
+        sig_type: SigType,
+        // I've seen a 0 bit signal parameter in a xilinx
+        // simulation before that gets assigned 1 bit values.
+        // I consider this to be bad behavior. We capture such
+        // errors in the following type.
+        signal_error: Option<String>,
+        num_bits: Option<usize>,
+        // TODO : may be able to remove self_idx
+        self_idx: SignalIdx,
+        // we could encounter a mix of pure values and strings
+        // for the same signal timeline
+        u8_timeline: Vec<u8>,
+        u8_timeline_markers: Vec<TimelineIdx>,
+        string_timeline: Vec<String>,
+        string_timeline_markers: Vec<TimelineIdx>,
+        scope_parent: ScopeIdx,
+    },
+    Alias {
+        name: String,
+        signal_alias: SignalIdx,
+    },
 }
 
-// We do a lot of arena allocation in this codebase.
-#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
-pub struct ScopeIdx(pub usize);
-
-#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
-pub struct SignalIdx(pub usize);
-
 #[derive(Debug)]
 pub(super) struct Scope {
     pub(super) name: String,
 
+    pub(super) parent_idx: Option<ScopeIdx>,
     pub(super) self_idx: ScopeIdx,
 
     pub(super) child_signals: Vec<SignalIdx>,
     pub(super) child_scopes: Vec<ScopeIdx>,
 }
 
+// TODO: document how timeline is represented
 #[derive(Debug)]
 pub struct VCD {
-    pub metadata: Metadata,
+    pub(super) metadata: Metadata,
-    // Since we only need to store values when there is an actual change
+    pub timeline: Vec<u8>,
-    // in the timeline, we keep a vector that stores the time at which an
+    pub timeline_markers: Vec<StartIdx>,
-    // event occurs. Time t is always stored/encoded as the minimum length sequence
+    pub(super) all_signals: Vec<Signal>,
-    // of u8.
-    // We essentially fill ``tmstmps_encoded_as_u8s`` with BigUints converted
-    // to sequences of little endian u8s.
-    // It is up to the signals to keep track of the start/stop indices in the
-    // vector of u8s that constitute a timestamp value. Signals don't have to
-    // keep track of all timestamp values, a given signal only needs to keep
-    // track of the timestamps at which the given signal value changes.
-    pub(super) tmstmps_encoded_as_u8s: Vec<u8>,
-    pub(super) all_signals: Vec<SignalEnum>,
     pub(super) all_scopes: Vec<Scope>,
-    pub(super) root_scopes: Vec<ScopeIdx>,
+    pub(super) scope_roots: Vec<ScopeIdx>,
-    pub(super) largest_timestamp: Option<BigUint>,
 }
 
 impl VCD {
-    pub fn root_scopes_by_idx(&self) -> Vec<ScopeIdx> {
+    // TODO : make this a generic traversal function that applies specified
-        self.root_scopes.clone()
+    // functions upon encountering scopes and signals
-    }
+    fn print_scope_tree(&self, root_scope_idx: ScopeIdx, depth: usize) {
-    pub fn child_scopes_by_idx(&self, scope_idx: ScopeIdx) -> Vec<ScopeIdx> {
+        let all_scopes = &self.all_scopes;
-        let ScopeIdx(idx) = scope_idx;
+        let all_signals = &self.all_signals;
-        let scope = &self.all_scopes[idx];
-        scope.child_scopes.clone()
-    }
-    pub fn get_children_signal_idxs(&self, scope_idx: ScopeIdx) -> Vec<SignalIdx> {
-        let ScopeIdx(idx) = scope_idx;
-        let scope = &self.all_scopes[idx];
-        scope.child_signals.clone()
-    }
-    pub fn scope_name_by_idx(&self, scope_idx: ScopeIdx) -> &String {
-        let ScopeIdx(idx) = scope_idx;
-        let scope = &self.all_scopes[idx];
-        &scope.name
-    }
-    pub fn signal_from_signal_idx(&self, idx: SignalIdx) -> Signal<'_> {
-        let SignalIdx(idx) = idx;
-        let signal_enum = &self.all_signals[idx];
-        return Signal(signal_enum);
-    }
-    /// We take in a Signal and attempt to de-alias that signal if it is of
-    /// variant ``Signal::Alias``. If it is of variant ``Signal::Alias`` and points to
-    /// another alias, that's an error. Otherwise, we return the ``Signal::Data``
-    /// pointed to by the ``Signal::Alias``.
-    /// If the Signal is of varint ``Signal::Data``, then that can be returned directly.
-    pub(super) fn dealiasing_signal_idx_to_signal_lookup_mut<'a>(
-        &'a mut self,
-        idx: &SignalIdx,
-    ) -> Result<&'a mut SignalEnum, String> {
-        // get the signal pointed to be SignalIdx from the arena
-        let SignalIdx(idx) = idx;
-        let signal = &self.all_signals[*idx];
 
-        // dereference signal if Signal::Alias, or keep idx if Signal::Data
+        let indent = " ".repeat(depth * 4);
-        let signal_idx = match signal {
+        let ScopeIdx(root_scope_idx) = root_scope_idx;
-            SignalEnum::Data { self_idx, .. } => *self_idx,
+        let root_scope = &all_scopes[root_scope_idx];
-            SignalEnum::Alias { signal_alias, .. } => *signal_alias,
+        let root_scope_name = &root_scope.name;
+
+        println!("{indent}scope: {root_scope_name}");
+
+        for SignalIdx(ref signal_idx) in &root_scope.child_signals {
+            let child_signal = &all_signals[*signal_idx];
+            let name = match child_signal {
+                Signal::Data { name, .. } => name,
+                Signal::Alias { name, .. } => name,
             };
+            println!("{indent} - sig: {name}")
+        }
+        println!();
 
-        // Should now  point to Signal::Data variant, or else there's an error
+        for scope_idx in &root_scope.child_scopes {
-        let SignalIdx(idx) = signal_idx;
+            self.print_scope_tree(*scope_idx, depth + 1);
-        let signal = self.all_signals.get_mut(idx).unwrap();
+        }
+    }
+
+    pub fn print_scopes(&self) {
+        for scope_root in &self.scope_roots {
+            self.print_scope_tree(*scope_root, 0);
+        }
+    }
+
+    pub fn print_longest_signal(&self) {
+        let mut idx = 0usize;
+        let mut max_len = 0usize;
+        let mut signal_name = String::new();
+
+        for signal in &self.all_signals {
             match signal {
-            SignalEnum::Data { .. } => Ok(signal),
+                Signal::Alias { .. } => {}
-            SignalEnum::Alias { .. } => Err(format!(
+                Signal::Data {
-                "Error near {}:{}. A signal alias shouldn't \
+                    name,
-                 point to a signal alias.",
+                    self_idx,
-                file!(),
+                    u8_timeline,
-                line!()
+                    ..
-            )),
+                } => {
+                    if u8_timeline.len() > max_len {
+                        max_len = u8_timeline.len();
+                        let SignalIdx(idx_usize) = self_idx;
+                        idx = *idx_usize;
+                        signal_name = name.clone();
+                    }
+                }
             }
         }
 
-    pub fn max_timestamp(&self) -> &Option<BigUint> {
+        dbg!((idx, max_len, signal_name));
-        &self.largest_timestamp
     }
 }

src/vcd/utilities.rs

@@ -1,86 +0,0 @@
-// Copyright (C) 2022 Yehowshua Immanuel
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
-#[derive(Debug)]
-pub(super) enum BinaryParserErrTypes {
-    XValue,
-    ZValue,
-    UValue,
-    HValue,
-    LValue,
-    DashValue,
-    WValue,
-    OtherValue(char),
-    TooLong,
-}
-
-// We build a quick and not so dirty bit string parser.
-fn base2_str_to_byte(word: &[u8]) -> Result<u8, BinaryParserErrTypes> {
-    let mut val = 0u8;
-
-    // shouldn't have more than 8 chars in str
-    let len = word.len();
-    if len > 8 {
-        return Err(BinaryParserErrTypes::TooLong);
-    }
-
-    let bit_lut = [
-        0b0000_0001u8,
-        0b0000_0010u8,
-        0b0000_0100u8,
-        0b0000_1000u8,
-        0b0001_0000u8,
-        0b0010_0000u8,
-        0b0100_0000u8,
-        0b1000_0000u8,
-    ];
-
-    for (idx, chr) in word.iter().rev().enumerate() {
-        match chr {
-            b'1' => val |= bit_lut[idx],
-            b'0' => {}
-            b'x' | b'X' => return Err(BinaryParserErrTypes::XValue),
-            b'z' | b'Z' => return Err(BinaryParserErrTypes::ZValue),
-            b'u' | b'U' => return Err(BinaryParserErrTypes::UValue),
-            b'l' | b'L' => return Err(BinaryParserErrTypes::LValue),
-            b'h' | b'H' => return Err(BinaryParserErrTypes::HValue),
-            b'w' | b'W' => return Err(BinaryParserErrTypes::WValue),
-            b'-' => return Err(BinaryParserErrTypes::DashValue),
-            _ => return Err(BinaryParserErrTypes::OtherValue(*chr as char)),
-        }
-    }
-
-    Ok(val)
-}
-
-pub(super) fn binary_str_to_vec_u8(binary_str: &str) -> Result<Vec<u8>, BinaryParserErrTypes> {
-    let mut vec_u8: Vec<u8> = Vec::new();
-    let binary_str_as_bytes = binary_str.as_bytes();
-
-    let mut tail_idx = binary_str_as_bytes.len();
-    // clamp head if provided binary str is less than 8 long
-    let mut head_idx = if tail_idx >= 8 {
-        binary_str_as_bytes.len() - 8
-    } else {
-        0
-    };
-    while tail_idx > 0 {
-        let curr_b_val = &binary_str_as_bytes[head_idx..tail_idx];
-        let val_u8 = base2_str_to_byte(curr_b_val)?;
-        vec_u8.push(val_u8);
-
-        if head_idx < 8 {
-            head_idx = 0
-        } else {
-            head_idx -= 8;
-        }
-
-        if tail_idx < 8 {
-            tail_idx = 0
-        } else {
-            tail_idx -= 8;
-        }
-    }
-    Ok(vec_u8)
-}

tests/files.rs

@@ -1,77 +0,0 @@
-// Copyright (C) 2022 Yehowshua Immanuel
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
-
-// TODO: we should eventually be able to only test on just
-// the files const
-pub const FILES: [&str; 31] = [
-    "./tests/vcd-files/aldec/SPI_Write.vcd",
-    "./tests/vcd-files/ghdl/alu.vcd",
-    "./tests/vcd-files/ghdl/idea.vcd",
-    "./tests/vcd-files/ghdl/pcpu.vcd",
-    "./tests/vcd-files/gtkwave-analyzer/perm_current.vcd",
-    "./tests/vcd-files/icarus/CPU.vcd",
-    "./tests/vcd-files/icarus/rv32_soc_TB.vcd",
-    "./tests/vcd-files/icarus/test1.vcd",
-    "./tests/vcd-files/model-sim/CPU_Design.msim.vcd",
-    "./tests/vcd-files/model-sim/clkdiv2n_tb.vcd",
-    "./tests/vcd-files/my-hdl/Simple_Memory.vcd",
-    "./tests/vcd-files/my-hdl/sigmoid_tb.vcd",
-    "./tests/vcd-files/my-hdl/top.vcd",
-    "./tests/vcd-files/ncsim/ffdiv_32bit_tb.vcd",
-    "./tests/vcd-files/quartus/mipsHardware.vcd",
-    "./tests/vcd-files/quartus/wave_registradores.vcd",
-    "./tests/vcd-files/questa-sim/dump.vcd",
-    "./tests/vcd-files/questa-sim/test.vcd",
-    "./tests/vcd-files/riviera-pro/dump.vcd",
-    "./tests/vcd-files/systemc/waveform.vcd",
-    "./tests/vcd-files/treadle/GCD.vcd",
-    "./tests/vcd-files/vcs/Apb_slave_uvm_new.vcd",
-    "./tests/vcd-files/vcs/datapath_log.vcd",
-    "./tests/vcd-files/vcs/processor.vcd",
-    "./tests/vcd-files/verilator/swerv1.vcd",
-    "./tests/vcd-files/verilator/vlt_dump.vcd",
-    "./tests/vcd-files/vivado/iladata.vcd",
-    "./tests/vcd-files/xilinx_isim/test.vcd",
-    "./tests/vcd-files/xilinx_isim/test1.vcd",
-    // TODO : add signal ignore list to handle bitwidth mismatches
-    "./tests/vcd-files/xilinx_isim/test2x2_regex22_string1.vcd",
-    "./tests/vcd-files/scope_with_comment.vcd",
-];
-
-pub const GOOD_DATE_FILES: [&str; 24] = [
-    "./test-vcd-files/aldec/SPI_Write.vcd",
-    "./test-vcd-files/ghdl/alu.vcd",
-    "./test-vcd-files/ghdl/idea.vcd",
-    "./test-vcd-files/ghdl/pcpu.vcd",
-    "./test-vcd-files/gtkwave-analyzer/perm_current.vcd",
-    "./test-vcd-files/icarus/CPU.vcd",
-    "./test-vcd-files/icarus/rv32_soc_TB.vcd",
-    "./test-vcd-files/icarus/test1.vcd",
-    "./test-vcd-files/model-sim/CPU_Design.msim.vcd",
-    "./test-vcd-files/model-sim/clkdiv2n_tb.vcd",
-    "./test-vcd-files/my-hdl/Simple_Memory.vcd",
-    "./test-vcd-files/my-hdl/sigmoid_tb.vcd",
-    "./test-vcd-files/my-hdl/top.vcd",
-    "./test-vcd-files/questa-sim/dump.vcd",
-    "./test-vcd-files/questa-sim/test.vcd",
-    "./test-vcd-files/riviera-pro/dump.vcd",
-    "./test-vcd-files/vcs/Apb_slave_uvm_new.vcd",
-    "./test-vcd-files/vcs/datapath_log.vcd",
-    "./test-vcd-files/vcs/processor.vcd",
-    "./test-vcd-files/verilator/swerv1.vcd",
-    "./test-vcd-files/verilator/vlt_dump.vcd",
-    "./test-vcd-files/xilinx_isim/test.vcd",
-    "./test-vcd-files/xilinx_isim/test1.vcd",
-    "./test-vcd-files/xilinx_isim/test2x2_regex22_string1.vcd",
-];
-
-pub const BAD_DATE_FILES: [&str; 6] = [
-    "./test-vcd-files/ncsim/ffdiv_32bit_tb.vcd",
-    "./test-vcd-files/quartus/mipsHardware.vcd",
-    "./test-vcd-files/quartus/wave_registradores.vcd",
-    "./test-vcd-files/systemc/waveform.vcd",
-    "./test-vcd-files/treadle/GCD.vcd",
-    "./test-vcd-files/vivado/iladata.vcd",
-];

tests/integration_test.rs

@@ -1,22 +0,0 @@
-// Copyright (C) 2022 Yehowshua Immanuel
-// This program is distributed under both the GPLV3 license
-// and the YEHOWSHUA license, both of which can be found at
-// the root of the folder containing the sources for this program.
-use std::fs::File;
-
-mod files;
-use files::*;
-
-#[test]
-fn parse_all_VCDs() {
-    // see if we can parse all signal trees successfully
-    for file_name in FILES {
-        let file = File::open(file_name).unwrap();
-        let vcd = fastwave_backend::parse_vcd(file);
-
-        if !vcd.is_ok() {
-            dbg!(file_name);
-            vcd.unwrap();
-        }
-    }
-}

tests/vcd-files/scope_with_comment.vcd

@@ -1,296 +0,0 @@
-$date
-	Sat Dec 26 15:33:14 2020
-$end
-$version
-	ModelSim Version 10.5b
-$end
-$timescale
-	1ns
-$end
-
-$scope module clkdiv2n_tb $end
-$comment foo $end
-$var reg 1 ! clk $end
-$var reg 1 " reset $end
-$var wire 1 # clk_out $end
-
-$scope module t1 $end
-$var parameter 32 $ WIDTH $end
-$var parameter 32 % N $end
-$var wire 1 & clk $end
-$var wire 1 ' reset $end
-$var wire 1 # clk_out $end
-$var reg 3 ( r_reg [2:0] $end
-$var wire 1 ) r_nxt [2] $end
-$var wire 1 * r_nxt [1] $end
-$var wire 1 + r_nxt [0] $end
-$var reg 1 , clk_track $end
-$upscope $end
-$comment foo $end
-$upscope $end
-$comment foo $end
-$enddefinitions $end
-#0
-$comment foo $end
-$dumpvars
-0!
-x"
-bx (
-x,
-b11 $
-b110 %
-x#
-x+
-x*
-x)
-x'
-0&
-$end
-#5
-1"
-1'
-b0 (
-0,
-1+
-0*
-0)
-0#
-#10
-1!
-1&
-#15
-0"
-0'
-#20
-0!
-0&
-#30
-1!
-1&
-b1 (
-0+
-1*
-#40
-0!
-0&
-#50
-1!
-1&
-b10 (
-1+
-#60
-0!
-0&
-#70
-1!
-1&
-b11 (
-0+
-0*
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-#80
-0!
-0&
-#90
-1!
-1&
-b100 (
-1+
-#100
-0!
-0&
-#110
-1!
-1&
-b101 (
-0+
-1*
-#120
-0!
-0&
-#130
-1!
-1&
-b0 (
-1,
-1+
-0*
-0)
-1#
-#140
-0!
-0&
-#150
-1!
-1&
-b1 (
-0+
-1*
-#160
-0!
-0&
-#170
-1!
-1&
-b10 (
-1+
-#180
-0!
-0&
-#190
-1!
-1&
-b11 (
-0+
-0*
-1)
-#200
-0!
-0&
-#210
-1!
-1&
-b100 (
-1+
-#220
-0!
-0&
-#230
-1!
-1&
-b101 (
-0+
-1*
-#240
-0!
-0&
-#250
-1!
-1&
-b0 (
-0,
-1+
-0*
-0)
-0#
-#260
-0!
-0&
-#270
-1!
-1&
-b1 (
-0+
-1*
-#280
-0!
-0&
-#290
-1!
-1&
-b10 (
-1+
-#300
-0!
-0&
-#310
-1!
-1&
-b11 (
-0+
-0*
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-#320
-0!
-0&
-#330
-1!
-1&
-b100 (
-1+
-#340
-0!
-0&
-#350
-1!
-1&
-b101 (
-0+
-1*
-#360
-0!
-0&
-#370
-1!
-1&
-b0 (
-1,
-1+
-0*
-0)
-1#
-#380
-0!
-0&
-#390
-1!
-1&
-b1 (
-0+
-1*
-#400
-0!
-0&
-#410
-1!
-1&
-b10 (
-1+
-#420
-0!
-0&
-#430
-1!
-1&
-b11 (
-0+
-0*
-1)
-#440
-0!
-0&
-#450
-1!
-1&
-b100 (
-1+
-#460
-0!
-0&
-#470
-1!
-1&
-b101 (
-0+
-1*
-#480
-0!
-0&
-#490
-1!
-1&
-b0 (
-0,
-1+
-0*
-0)
-0#
-#500
-0!
-0&
-#510
-1!
-1&
-b1 (
-0+
-1*