vcd-writer

Port PyVCD package from python to C++

Visit PyVCD on GitHub.

It writes Value Change Dump (VCD) files as specified in IEEE 1364-2005.

Install with CMake

Create a CMakeLists.txt file on the root directory of your project and use the CPMAddPackage command to include this library in your project. Here's an example of a CMakeLists.txt file:

cmake_minimum_required(VERSION 3.14)
project(
    projectName
    VERSION 2025.0.1 
    LANGUAGES CXX
)

include(cmake/CPM.cmake)

CPMAddPackage(
    NAME libvcdwriter
    GITHUB_REPOSITORY favorart/vcd-writer 
    GIT_TAG master
    DOWNLOAD_ONLY TRUE
    options
        "VCDWRITER_BUILD_MAIN OFF"
        "VCDWRITER_BUILD_TESTS OFF"
)

add_subdirectory(${libvcdwriter_SOURCE_DIR})

add_executable(mainApp ../main.cpp)
target_link_libraries(mainApp PRIVATE vcdwriter::vcdwriter_shared)
 

Install with Make

# install gtests (ubuntu)
sudo apt-get install libgtest-dev

# compile library and tests
make

# run simple test
./test/main

# run unit tests
./test/test

Default result:

build/libvcdwriter.a    # static library
build/libvcdwriter.so   # shared library
build/main              # simple test execution file
build/test              # unit tests  execution file

Quick Start

#include "vcd_writer.h"

using namespace vcd;

HeadPtr head = makeVCDHeader(TimeScale::ONE, TimeScaleUnit::ns, utils::now());
std::string filename = "dump.vcd";
VCDWriter writer(filename, head);

VarPtr counter_var = writer.register_var("a.b.c", "counter", VariableType::integer, 8);
VarPtr var_var = writer.register_var("a.b", "var", VariableType::integer, 8);

for (int timestamp = 0; timestamp < 5; ++timestamp)
{
	const int c_val = 10 + timestamp * 2;
	const int v_val = 11 + timestamp * 2;
	writer.change(counter_var, timestamp, std::bitset<8>(c_val).to_string());
	writer.change(var_var, timestamp, std::bitset<8>(v_val).to_string());
}

Output:

$timescale 1 ns $end
$date 2022-04-18 11:12:38 $end
$scope module a $end
$scope module b $end
$var integer 8 1 var $end
$upscope $end
$scope module b $end
$scope module c $end
$var integer 8 0 counter $end
$upscope $end
$upscope $end
$upscope $end
$enddefinitions $end
#0
$dumpvars
b00001010 0
b00001011 1
$end
#1
b00001100 0
b00001101 1
#2
b00001110 0
b00001111 1
#3
b00010000 0
b00010001 1
#4
b00010010 0
b00010011 1