- update README to reflect correct performance numbers

- add tasks to README
 - repair bug in events.rs that prevented most events in VCD file from being parsed
 - add some initial code for timeline scrubbing

Cargo.toml

@@ -12,5 +12,5 @@ debug = 1
 num = "0.4"
 clap = { version = "3.1.8", features = ["derive"] }
 chrono = "0.4"
+# TODO : remove itertools once date parser is reworked.
 itertools = "0.10.3"
-backtrace = "0.3"

README.md

@@ -37,7 +37,7 @@ slower.
 
 | Software | Time(s) | Memory(MB) |
 |----------|---------|------------|
-| FastWave | ~15.09  | 267.3      |
+| FastWave | ~27.30  | 1100+      |
 | GtkWave  | ~30     | 89.8       |
 
 
@@ -67,7 +67,10 @@ Here's a command to test on a malformed VCD:
 
 # TODO
 
-## Features
+## Features and Other
+ - [ ] add timeline value scanner code
+ - [ ] test against large waveform directly within SpinalHDL
+ - [ ] (a bit of work) consolidate error messages in validation phase
  - [ ] be explicit with imports, remove exports as possible
        once FastWave is known to be fairly stable.
  - [ ] do a read through all the code
@@ -88,5 +91,8 @@ Here's a command to test on a malformed VCD:
  - [ ] Handle TODOs
  - [ ] Remove debug code/comments.
 
+## Documentation
+ - [ ] Document indexing structure with diagram and possibly include the rational
+
 ## Marketing
  - [ ] Send survey to community 

src/main.rs

@@ -25,7 +25,7 @@ fn main() -> std::io::Result<()> {
     let elapsed = now.elapsed();
     println!("Elapsed: {:.2?}", elapsed);
 
-    std::thread::sleep(std::time::Duration::from_secs(10));
+    // std::thread::sleep(std::time::Duration::from_secs(10));
 
     Ok(())
 }

src/vcd/parse.rs

@@ -1,4 +1,4 @@
-use num::BigInt;
+use num::BigUint;
 use std::collections::HashMap;
 use std::fs::File;
 

src/vcd/parse/events.rs

@@ -15,7 +15,7 @@ pub(super) fn parse_events<'a>(
             break;
         };
 
-        let (word, cursor) = next_word!(word_reader)?;
+        let (word, cursor) = next_word.unwrap();
         let Cursor(Line(_), Word(word_in_line_idx)) = cursor;
         // we only want to match on the first word in a line
         if word_in_line_idx != 1 {
@@ -26,14 +26,14 @@ pub(super) fn parse_events<'a>(
             "#" => {
                 let value = &word[1..];
                 let (f, l) = (file!(), line!());
-                let value = BigInt::parse_bytes(value.as_bytes(), 10)
+                let value = BigUint::parse_bytes(value.as_bytes(), 10)
                     .ok_or(())
                     .map_err(|_| {
                         format!(
                             "Error near {f}:{l}. Failed to parse {value} as BigInt at {cursor:?}"
                         )
                     })?;
-                let (_, mut value) = value.to_bytes_le();
+                let mut value = value.to_bytes_le();
                 // TODO : u32 helps with less memory, but should ideally likely be
                 // configurable.
                 let (f, l) = (file!(), line!());

src/vcd/reader.rs

@@ -5,8 +5,6 @@ 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)]

src/vcd/types.rs

@@ -1,4 +1,6 @@
+use super::utilities::{ordered_binary_lookup_u8, LookupErrors};
 use chrono::prelude::*;
+use num::{BigUint, Zero};
 
 #[derive(Debug)]
 pub(super) struct Version(pub String);
@@ -72,6 +74,26 @@ pub(super) enum Signal {
     },
 }
 
+#[derive(Debug)]
+pub(super) enum TimelineQueryResults {
+    BigUint(BigUint),
+    String(String),
+}
+
+impl Scope {
+    pub(super) fn query_value(&self, time: TimelineIdx) -> Result<TimelineQueryResults, String> {
+        // match
+        // assert
+        // ordered_binary_lookup_u8(
+        //     &value_sequence_as_bytes_u8,
+        //     4,
+        //     &timeline_cursors,
+        //     TimelineIdx(scrubbing_cursor),
+        // );
+        Ok(TimelineQueryResults::String("".to_string()))
+    }
+}
+
 #[derive(Debug)]
 pub(super) struct Scope {
     pub(super) name: String,

src/vcd/utilities.rs

@@ -1,7 +1,5 @@
 use super::*;
 
-use std::cmp::Ordering;
-
 #[derive(Debug)]
 pub(super) enum BinaryParserErrTypes {
     XValue,
@@ -77,61 +75,105 @@ pub(super) fn binary_str_to_vec_u8(binary_str: &str) -> Result<Vec<u8>, BinaryPa
     Ok(vec_u8)
 }
 
-// TODO : modify ordered_binary_lookup to support VCD timeline lookup
-// and return time in signature
-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();
+use num::{BigUint, Zero};
 
-    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;
+#[derive(Debug)]
+pub(super) enum LookupErrors {
+    PreTimeline {
+        desired_time: TimelineIdx,
+        timeline_start_time: TimelineIdx,
+    },
+    EmptyTimeline,
+    TimelineNotMultiple,
+    OrderingFailure,
 }
 
-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;
+pub(super) fn ordered_binary_lookup_u8(
+    value_sequence_as_bytes: &Vec<u8>,
+    bytes_per_value: usize,
+    timeline_cursors: &Vec<TimelineIdx>,
+    desired_time: TimelineIdx,
+) -> Result<BigUint, LookupErrors> {
+    // timeline must not be empty
+    if timeline_cursors.is_empty() {
+        return Err(LookupErrors::EmptyTimeline);
+    }
 
+    // assertion that value_sequence is a proper multiple of
+    // timeline_markers
+    if value_sequence_as_bytes.len() != (timeline_cursors.len() * bytes_per_value) {
+        return Err(LookupErrors::TimelineNotMultiple);
+    }
+
+    let TimelineIdx(desired_time) = desired_time;
+
+    // check if we're requesting a value that occurs before the recorded
+    // start of the timeline
+    let TimelineIdx(timeline_start_time) = timeline_cursors.first().unwrap();
+    if desired_time < *timeline_start_time {
+        return Err(LookupErrors::PreTimeline {
+            desired_time: TimelineIdx(desired_time),
+            timeline_start_time: TimelineIdx(*timeline_start_time),
+        });
+    }
+
+    let mut lower_idx = 0usize;
+    let mut upper_idx = timeline_cursors.len() - 1;
+
+    // check if we're requesting a value that occurs beyond the end of the timeline,
+    // if so, return the last value in this timeline
+    let TimelineIdx(timeline_end_time) = timeline_cursors.last().unwrap();
+    if desired_time > *timeline_end_time {
+        let range = (value_sequence_as_bytes.len() - bytes_per_value)..;
+        let value_by_bytes = &value_sequence_as_bytes[range];
+        let value = BigUint::from_bytes_le(value_by_bytes);
+
+        return Ok(value);
+    }
+
+    // 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 (str_val, signal_idx) = map.get(mid_idx).unwrap();
-        let ordering = compare_strs(key, str_val.as_str());
+        let TimelineIdx(curr_time) = timeline_cursors[mid_idx];
+        let ordering = curr_time.cmp(&desired_time);
 
         match ordering {
-            Ordering::Less => {
-                upper_idx = mid_idx - 1;
-            }
-            Ordering::Equal => {
-                return Ok(*signal_idx);
-            }
-            Ordering::Greater => {
+            std::cmp::Ordering::Less => {
                 lower_idx = mid_idx + 1;
             }
+            std::cmp::Ordering::Equal => {
+                let u8_timeline_start_idx = mid_idx * bytes_per_value;
+                let u8_timeline_end_idx = u8_timeline_start_idx + bytes_per_value;
+                let range = u8_timeline_start_idx..u8_timeline_end_idx;
+                let value_by_bytes = &value_sequence_as_bytes[range];
+                let value = BigUint::from_bytes_le(value_by_bytes);
+                return Ok(value);
+            }
+            std::cmp::Ordering::Greater => {
+                upper_idx = mid_idx - 1;
+            }
         }
     }
 
-    return Err(format!(
-        "Error near {}:{}. Unable to find key: `{key}` in the map.",
-        file!(),
-        line!()
-    ));
+    let idx = lower_idx - 1;
+    let TimelineIdx(left_time) = timeline_cursors[idx];
+    let TimelineIdx(right_time) = timeline_cursors[idx + 1];
+
+    let ordered_left = left_time < desired_time;
+    let ordered_right = desired_time < right_time;
+    if !(ordered_left && ordered_right) {
+        return Err(LookupErrors::OrderingFailure);
+    }
+
+    let u8_timeline_start_idx = idx * bytes_per_value;
+    let u8_timeline_end_idx = u8_timeline_start_idx + bytes_per_value;
+    let range = u8_timeline_start_idx..u8_timeline_end_idx;
+    let value_by_bytes = &value_sequence_as_bytes[range];
+    let value = BigUint::from_bytes_le(value_by_bytes);
+
+    return Ok(value);
 }