ppsspp/audio/wav_read.cpp

#include "base/basictypes.h"
#include "base/logging.h"
#include "audio/wav_read.h"
#include "file/chunk_file.h"

short *wav_read(const char *filename,
                int *num_samples, int *sample_rate,
                int *num_channels) {
  ChunkFile cf(filename, true);
  if (cf.failed()) {
    WLOG("ERROR: Wave file %s could not be opened", filename);
    return 0;
  }

  short *data = 0;
  int samplesPerSec, avgBytesPerSec,wBlockAlign,wBytesPerSample;
  if (cf.descend('RIFF')) {
    cf.readInt(); //get past 'WAVE'
    if (cf.descend('fmt ')) //enter the format chunk 
    {
      int temp;
      temp = cf.readInt();
      int format = temp & 0xFFFF;
      if (format != 1) {
        cf.ascend();
        cf.ascend();
        ELOG("Error - bad format");
        return NULL;
      }
      *num_channels = temp >> 16;
      samplesPerSec  = cf.readInt();
      avgBytesPerSec = cf.readInt();

      temp           = cf.readInt();
      wBlockAlign    = temp & 0xFFFF;          
      wBytesPerSample = temp >> 16;
      cf.ascend();
      // ILOG("got fmt data: %i", samplesPerSec);
    } else {
      ELOG("Error - no format chunk in wav");
      cf.ascend();
      return NULL;
    }

    if (cf.descend('data'))       //enter the data chunk
    {
      int numBytes = cf.getCurrentChunkSize();
      int numSamples = numBytes / wBlockAlign;
      data = (short *)malloc(sizeof(short) * numSamples * *num_channels);
      *num_samples = numSamples;
      if (wBlockAlign == 2 && *num_channels == 1) {
        cf.readData((uint8*)data,numBytes);
      } else {
        ELOG("Error - bad blockalign or channels");
        free(data);
        return NULL;
      }
      cf.ascend();
    } else {
      ELOG("Error - no data chunk in wav");
      cf.ascend();
      return NULL;
    }
    cf.ascend();
  } else {
    ELOG("Could not descend into RIFF file");
    return NULL;
  }
  *sample_rate = samplesPerSec;
  ILOG("read wav %s, length %i, rate %i", filename, *num_samples, *sample_rate);
  return data;
}