https://github.com/filmil/go-vcd-parser
https://github.com/filmil/go-vcd-parser
Last synced: 2 months ago
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- Host: GitHub
- URL: https://github.com/filmil/go-vcd-parser
- Owner: filmil
- License: apache-2.0
- Created: 2024-10-13T06:28:05.000Z (7 months ago)
- Default Branch: main
- Last Pushed: 2024-12-28T07:49:16.000Z (4 months ago)
- Last Synced: 2025-01-08T07:21:41.655Z (4 months ago)
- Language: Go
- Size: 1.78 MB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Value Change Dump (VCD) File parser
[](https://github.com/filmil/go-vcd-parser/workflows/Test/badge.svg)
This is a parser for the Value Change Dump files, a.k.a VCD file format. The
file format is defined in the [IEEE Standard 1800-2003][vv]. Specifically, the
format supported at the moment is the 4-value format. Some pragmatic extensions
are supported, such as those produced by the `nvc` VHDL simulator.
The correct behavior of the parser is guarded by a suite of tests. Tests
include:
- Unit tests for specific VCD stanzas
- Unit tests for intersting VCD snippets encountered in the wild.
- Integration tests that parse realistic VCD files that were sampled from
actual uses.
## Why?
- **I wanted one written in go** (compiled, static, well-tested). Most open source
alternatives I could find are written in Python, Perl and C++ (see the
References section below).
- **I wanted one that is *tested***. Most alternatives contain no tests at all. Some
that I have actually tried would just throw an exception when faced with a
realistic VCD file.
- **I needed a confirmation that the code can parse realistic VCD files.** Hence,
the test coverage. And samples of realistic VCD files used for testing.
## Prerequisites
* Install `bazel` using the [bazelisk method][ii].
It should be possible to use the vanilla go environment as well.
## Test
From the root directory, run:
```
bazel test //...
```
This should always pass. [Report a bug][bb] if not.
If you have `go` installed, you can also run:
```
go test ./...
```
While this should pass, I will not necessarily spend time to make it work
with the go toolkit.
## Limitations
- The parser is not streaming. It produces an in-memory representation of the
VCD file before it is able to write a parsed representation out. As VCD files
can get extraordinarily large, you may find that some realistic large files
can not be parsed with success.
## Troubleshooting
If you find a problem VCD file, file a bug report and consider sending the file.
Minimal examples are preferred.
# References
Prior art:
- https://github.com/ben-marshall/verilog-vcd-parser
- https://wohali.github.io/vcd_parsealyze
- https://github.com/kmurray/libvcdparse
- https://pypi.org/project/pyDigitalWaveTools
- https://metacpan.org/pod/Verilog::VCD
- https://pyvcd.readthedocs.io/en/latest/vcd.reader.html
- https://pypi.org/project/vcdvcd/
- https://github.com/gtkwave/gtkwave/blob/0a800de96255f7fb11beadb6729fdf670da76ecb/src/vcd_saver.c#L123
- https://github.com/nickg/nvc/blob/8696f99160eba01c1beb6e243506af57ba9893ca/src/rt/wave.h#L28
- https://github.com/kevinmehall/rust-vcd
[bb]: https://github.com/filmil/go-vcd-parser/issues
[ii]: https://hdlfactory.com/note/2024/08/24/bazel-installation-via-the-bazelisk-method/
[vv]: https://ieeexplore.ieee.org/document/10458102