From fd31ec135816fbec0d25b1b3eaa886d6df8dd110 Mon Sep 17 00:00:00 2001
From: Yehowshua Immanuel <yehowshua@theperfect.computer>
Date: Thu, 11 Aug 2022 19:58:21 -0400
Subject: [PATCH] notable near 2x speedup in load time, and near 3x reduction
 in memory consumption

---
 src/main.rs               |  4 +++-
 src/vcd/parse/events.rs   | 17 +++++++++--------
 src/vcd/parse/metadata.rs |  8 +++-----
 src/vcd/reader.rs         | 39 ---------------------------------------
 4 files changed, 15 insertions(+), 53 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index f6d9d4b..d4b5311 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -21,9 +21,11 @@ fn main() -> std::io::Result<()> {
 
     let file = File::open(&args.path)?;
     let vcd = parse_vcd(file).unwrap();
-    // vcd.
+
     let elapsed = now.elapsed();
     println!("Elapsed: {:.2?}", elapsed);
 
+    std::thread::sleep(std::time::Duration::from_secs(10));
+
     Ok(())
 }
diff --git a/src/vcd/parse/events.rs b/src/vcd/parse/events.rs
index 062aa41..f3c1aa2 100644
--- a/src/vcd/parse/events.rs
+++ b/src/vcd/parse/events.rs
@@ -5,9 +5,6 @@ pub(super) fn parse_events<'a>(
     vcd: &'a mut VCD,
     signal_map: &mut HashMap<String, SignalIdx>,
 ) -> Result<(), String> {
-    // let hash_time = std::time::Duration::ZERO;
-    // let hash_time = std::time::Duration::ZERO;
-
     loop {
         let next_word = word_reader.next_word();
 
@@ -18,7 +15,7 @@ pub(super) fn parse_events<'a>(
             break;
         };
 
-        let (word, cursor) = next_word.unwrap();
+        let (word, cursor) = next_word!(word_reader)?;
         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 {
@@ -29,10 +26,13 @@ pub(super) fn parse_events<'a>(
             "#" => {
                 let value = &word[1..];
                 let (f, l) = (file!(), line!());
-                let value = BigInt::parse_bytes(value.as_bytes(), 10).ok_or(
-                    format!("Error near {f}:{l}. Failed to parse {value} as BigInt at {cursor:?}")
-                        .as_str(),
-                )?;
+                let value = BigInt::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();
                 // TODO : u32 helps with less memory, but should ideally likely be
                 // configurable.
@@ -177,6 +177,7 @@ pub(super) fn parse_events<'a>(
                                 (num_bits / 8) + if (num_bits % 8) > 0 { 1 } else { 0 };
 
                             while curr_num_bytes < bytes_required {
+                                // TODO: remove once library is known to be stable
                                 // useful for debugging
                                 // let err = format!("Error at {cursor:?}.\
                                 // num_bits = {num_bits}, \
diff --git a/src/vcd/parse/metadata.rs b/src/vcd/parse/metadata.rs
index 887a94c..91954e8 100644
--- a/src/vcd/parse/metadata.rs
+++ b/src/vcd/parse/metadata.rs
@@ -183,8 +183,7 @@ pub(super) fn parse_timescale(
                     file!(),
                     line!()
                 )),
-            }
-            .unwrap();
+            }?;
 
             (Some(scalar), unit)
         } else {
@@ -200,8 +199,7 @@ pub(super) fn parse_timescale(
                     file!(),
                     line!()
                 )),
-            }
-            .unwrap();
+            }?;
 
             (Some(scalar), unit)
         }
@@ -293,7 +291,7 @@ pub(super) fn parse_metadata(word_reader: &mut WordReader) -> Result<Metadata, S
 
                             // store date and exit loop if a match is found
                             if parsed_date.is_ok() {
-                                metadata.date = Some(parsed_date.unwrap());
+                                metadata.date = Some(parsed_date?);
                                 break;
                             }
                         }
diff --git a/src/vcd/reader.rs b/src/vcd/reader.rs
index 4a8f45f..166a5cd 100644
--- a/src/vcd/reader.rs
+++ b/src/vcd/reader.rs
@@ -127,42 +127,3 @@ macro_rules! curr_word {
 
 pub(super) use curr_word;
 pub(super) use next_word;
-
-// fn previous_symbol(level: u32) -> Option<BacktraceSymbol> {
-//     let (trace, curr_file, curr_line) = (Backtrace::new(), file!(), line!());
-//     let frames = trace.frames();
-//     frames
-//         .iter()
-//         .flat_map(BacktraceFrame::symbols)
-//         .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()
-// }
-
-// impl From<FileStatus> for String {
-//     fn from(f: FileStatus) -> String {
-//         let sym = previous_symbol(1);
-//         let filename = sym
-//             .as_ref()
-//             .and_then(BacktraceSymbol::filename)
-//             .map_or(None, |path| path.to_str())
-//             .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());
-
-//         match f {
-//             FileStatus::Eof => format!(
-//                 "Error near {filename}:{lineno} \
-//                  No more words left in vcd file."
-//             ),
-//         }
-//     }
-// }