Common: Add WAVWriter class

src/common/CMakeLists.txt

@@ -54,6 +54,8 @@ add_library(common
   timestamp.cpp
   timestamp.h
   types.h
+  wav_writer.cpp
+  wav_Writer.h
 )
 
 target_include_directories(common PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/..")

src/common/common.vcxproj

@@ -70,6 +70,7 @@
     <ClInclude Include="timestamp.h" />
     <ClInclude Include="types.h" />
     <ClInclude Include="cd_xa.h" />
+    <ClInclude Include="wav_writer.h" />
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="assert.cpp" />
@@ -102,6 +103,7 @@
     <ClCompile Include="string_util.cpp" />
     <ClCompile Include="timer.cpp" />
     <ClCompile Include="timestamp.cpp" />
+    <ClCompile Include="wav_writer.cpp" />
   </ItemGroup>
   <ItemGroup>
     <Natvis Include="bitfield.natvis" />

src/common/common.vcxproj.filters

@@ -52,6 +52,7 @@
     </ClInclude>
     <ClInclude Include="hash_combine.h" />
     <ClInclude Include="progress_callback.h" />
+    <ClInclude Include="wav_writer.h" />
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="jit_code_buffer.cpp" />
@@ -100,6 +101,7 @@
     </ClCompile>
     <ClCompile Include="cd_image_chd.cpp" />
     <ClCompile Include="progress_callback.cpp" />
+    <ClCompile Include="wav_writer.cpp" />
   </ItemGroup>
   <ItemGroup>
     <Natvis Include="bitfield.natvis" />

src/common/wav_writer.cpp

@@ -0,0 +1,115 @@
+#include "wav_writer.h"
+#include "file_system.h"
+#include "log.h"
+Log_SetChannel(WAVWriter);
+
+#pragma pack(push, 1)
+struct WAV_HEADER
+{
+  u32 chunk_id; // RIFF
+  u32 chunk_size;
+  u32 format; // WAVE
+
+  struct FormatChunk
+  {
+    u32 chunk_id; // "fmt "
+    u32 chunk_size;
+    u16 audio_format; // pcm = 1
+    u16 num_channels;
+    u32 sample_rate;
+    u32 byte_rate;
+    u16 block_align;
+    u16 bits_per_sample;
+  } fmt_chunk;
+
+  struct DataChunkHeader
+  {
+    u32 chunk_id; // "data "
+    u32 chunk_size;
+  } data_chunk_header;
+};
+#pragma pack(pop)
+
+namespace Common {
+
+WAVWriter::WAVWriter() = default;
+
+WAVWriter::~WAVWriter()
+{
+  if (IsOpen())
+    Close();
+}
+
+bool WAVWriter::Open(const char* filename, u32 sample_rate, u32 num_channels)
+{
+  if (IsOpen())
+    Close();
+
+  m_file = FileSystem::OpenCFile(filename, "wb");
+  if (!m_file)
+    return false;
+
+  m_sample_rate = sample_rate;
+  m_num_channels = num_channels;
+
+  if (!WriteHeader())
+  {
+    Log_ErrorPrintf("Failed to write header to file");
+    m_sample_rate = 0;
+    m_num_channels = 0;
+    std::fclose(m_file);
+    m_file = nullptr;
+    return false;
+  }
+
+  return true;
+}
+
+void WAVWriter::Close()
+{
+  if (!IsOpen())
+    return;
+
+  if (std::fseek(m_file, 0, SEEK_SET) != 0 || !WriteHeader())
+    Log_ErrorPrintf("Failed to re-write header on file, file may be unplayable");
+
+  std::fclose(m_file);
+  m_file = nullptr;
+  m_sample_rate = 0;
+  m_num_channels = 0;
+  m_num_frames = 0;
+}
+
+void WAVWriter::WriteFrames(const s16* samples, u32 num_frames)
+{
+  const u32 num_frames_written =
+    static_cast<u32>(std::fwrite(samples, sizeof(s16) * m_num_channels, num_frames, m_file));
+  if (num_frames_written != num_frames)
+    Log_ErrorPrintf("Only wrote %u of %u frames to output file", num_frames_written);
+
+  m_num_frames += num_frames_written;
+}
+
+bool WAVWriter::WriteHeader()
+{
+  const u32 data_size = sizeof(SampleType) * m_num_channels * m_num_frames;
+
+  WAV_HEADER header = {};
+  header.chunk_id = 0x46464952; // 0x52494646
+  header.chunk_size = sizeof(WAV_HEADER) - 8 + data_size;
+  header.format = 0x45564157;             // 0x57415645
+  header.fmt_chunk.chunk_id = 0x20746d66; // 0x666d7420
+  header.fmt_chunk.chunk_size = sizeof(header.fmt_chunk) - 8;
+  header.fmt_chunk.audio_format = 1;
+  header.fmt_chunk.num_channels = static_cast<u16>(m_num_channels);
+  header.fmt_chunk.sample_rate = m_sample_rate;
+  header.fmt_chunk.byte_rate = m_sample_rate * m_num_channels * sizeof(SampleType);
+  header.fmt_chunk.block_align = static_cast<u16>(m_num_channels * sizeof(SampleType));
+  header.fmt_chunk.bits_per_sample = 16;
+  header.data_chunk_header.chunk_id = 0x61746164; // 0x64617461
+  header.data_chunk_header.chunk_size = data_size;
+
+  return (std::fwrite(&header, sizeof(header), 1, m_file) == 1);
+}
+
+} // namespace Common

src/common/wav_writer.h

@@ -0,0 +1,31 @@
+#pragma once
+#include "types.h"
+#include <cstdio>
+
+namespace Common {
+
+class WAVWriter
+{
+public:
+  WAVWriter();
+  ~WAVWriter();
+
+  ALWAYS_INLINE bool IsOpen() const { return (m_file != nullptr); }
+
+  bool Open(const char* filename, u32 sample_rate, u32 num_channels);
+  void Close();
+
+  void WriteFrames(const s16* samples, u32 num_frames);
+
+private:
+  using SampleType = s16;
+
+  bool WriteHeader();
+
+  std::FILE* m_file = nullptr;
+  u32 m_sample_rate = 0;
+  u32 m_num_channels = 0;
+  u32 m_num_frames = 0;
+};
+
+} // namespace Common