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      1 /*
      2  *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #include "webrtc/common_audio/wav_writer.h"
     12 
     13 #include <algorithm>
     14 #include <cstdio>
     15 #include <limits>
     16 
     17 #include "webrtc/base/checks.h"
     18 #include "webrtc/common_audio/include/audio_util.h"
     19 #include "webrtc/common_audio/wav_header.h"
     20 
     21 namespace webrtc {
     22 
     23 // We write 16-bit PCM WAV files.
     24 static const WavFormat kWavFormat = kWavFormatPcm;
     25 static const int kBytesPerSample = 2;
     26 
     27 WavFile::WavFile(const std::string& filename, int sample_rate, int num_channels)
     28     : sample_rate_(sample_rate),
     29       num_channels_(num_channels),
     30       num_samples_(0),
     31       file_handle_(fopen(filename.c_str(), "wb")) {
     32   CHECK(file_handle_);
     33   CHECK(CheckWavParameters(num_channels_,
     34                            sample_rate_,
     35                            kWavFormat,
     36                            kBytesPerSample,
     37                            num_samples_));
     38 
     39   // Write a blank placeholder header, since we need to know the total number
     40   // of samples before we can fill in the real data.
     41   static const uint8_t blank_header[kWavHeaderSize] = {0};
     42   CHECK_EQ(1u, fwrite(blank_header, kWavHeaderSize, 1, file_handle_));
     43 }
     44 
     45 WavFile::~WavFile() {
     46   Close();
     47 }
     48 
     49 void WavFile::WriteSamples(const int16_t* samples, size_t num_samples) {
     50 #ifndef WEBRTC_ARCH_LITTLE_ENDIAN
     51 #error "Need to convert samples to little-endian when writing to WAV file"
     52 #endif
     53   const size_t written =
     54       fwrite(samples, sizeof(*samples), num_samples, file_handle_);
     55   CHECK_EQ(num_samples, written);
     56   num_samples_ += static_cast<uint32_t>(written);
     57   CHECK(written <= std::numeric_limits<uint32_t>::max() ||
     58         num_samples_ >= written);  // detect uint32_t overflow
     59   CHECK(CheckWavParameters(num_channels_,
     60                            sample_rate_,
     61                            kWavFormat,
     62                            kBytesPerSample,
     63                            num_samples_));
     64 }
     65 
     66 void WavFile::WriteSamples(const float* samples, size_t num_samples) {
     67   static const size_t kChunksize = 4096 / sizeof(uint16_t);
     68   for (size_t i = 0; i < num_samples; i += kChunksize) {
     69     int16_t isamples[kChunksize];
     70     const size_t chunk = std::min(kChunksize, num_samples - i);
     71     RoundToInt16(samples + i, chunk, isamples);
     72     WriteSamples(isamples, chunk);
     73   }
     74 }
     75 
     76 void WavFile::Close() {
     77   CHECK_EQ(0, fseek(file_handle_, 0, SEEK_SET));
     78   uint8_t header[kWavHeaderSize];
     79   WriteWavHeader(header, num_channels_, sample_rate_, kWavFormat,
     80                  kBytesPerSample, num_samples_);
     81   CHECK_EQ(1u, fwrite(header, kWavHeaderSize, 1, file_handle_));
     82   CHECK_EQ(0, fclose(file_handle_));
     83   file_handle_ = NULL;
     84 }
     85 
     86 }  // namespace webrtc
     87 
     88 rtc_WavFile* rtc_WavOpen(const char* filename,
     89                          int sample_rate,
     90                          int num_channels) {
     91   return reinterpret_cast<rtc_WavFile*>(
     92       new webrtc::WavFile(filename, sample_rate, num_channels));
     93 }
     94 
     95 void rtc_WavClose(rtc_WavFile* wf) {
     96   delete reinterpret_cast<webrtc::WavFile*>(wf);
     97 }
     98 
     99 void rtc_WavWriteSamples(rtc_WavFile* wf,
    100                          const float* samples,
    101                          size_t num_samples) {
    102   reinterpret_cast<webrtc::WavFile*>(wf)->WriteSamples(samples, num_samples);
    103 }
    104 
    105 int rtc_WavSampleRate(const rtc_WavFile* wf) {
    106   return reinterpret_cast<const webrtc::WavFile*>(wf)->sample_rate();
    107 }
    108 
    109 int rtc_WavNumChannels(const rtc_WavFile* wf) {
    110   return reinterpret_cast<const webrtc::WavFile*>(wf)->num_channels();
    111 }
    112 
    113 uint32_t rtc_WavNumSamples(const rtc_WavFile* wf) {
    114   return reinterpret_cast<const webrtc::WavFile*>(wf)->num_samples();
    115 }
    116