wavefile.c

   1
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include "wavefile.h"
   5
   6 wavefile_t *waveopen(char *filename, char **errorstring)
   7 {
   8         int validfmt, position, length, l;
   9         char *error;
  10         wavefile_t *w;
  11         FILE *file;
  12         unsigned char buffer[1024];
  13         error = NULL;
  14         file = fopen(filename, "rb");
  15         if (file)
  16         {
  17                 w = malloc(sizeof(*w));
  18                 memset(w, 0, sizeof(*w));
  19                 if (w)
  20                 {
  21                         w->file = file;
  22                         if (fread(buffer, 12, 1, w->file))
  23                         {
  24                                 if (!memcmp(buffer, "RIFF", 4))
  25                                 {
  26                                         if (!memcmp(buffer + 8, "WAVE", 4))
  27                                         {
  28                                                 validfmt = 0;
  29                                                 for(;;)
  30                                                 {
  31                                                         if (!fread(buffer, 8, 1, w->file))
  32                                                         {
  33                                                                 //error = "error reading chunk\n");
  34                                                                 break;
  35                                                         }
  36                                                         position = ftell(w->file);
  37                                                         length = buffer[4] | (buffer[5] << 8) | (buffer[6] << 16) | (buffer[7] << 24);
  38                                                         if (!memcmp(buffer, "fmt ", 4))
  39                                                         {
  40                                                                 validfmt = 0;
  41                                                                 l = length;
  42                                                                 if (l > 16)
  43                                                                         l = 16;
  44                                                                 if (!fread(buffer, l, 1, w->file))
  45                                                                 {
  46                                                                         error = "error reading \"fmt \" chunk\n";
  47                                                                         break;
  48                                                                 }
  49                                                                 w->info_format = buffer[0] | (buffer[1] << 8);
  50                                                                 if (w->info_format != 1)
  51                                                                 {
  52                                                                         error = "only PCM format supported\n";
  53                                                                         break;
  54                                                                 }
  55                                                                 w->info_channels = buffer[2] | (buffer[3] << 8);
  56                                                                 if (w->info_channels != 1 && w->info_channels != 2)
  57                                                                 {
  58                                                                         error = "only mono and stereo supported\n";
  59                                                                         break;
  60                                                                 }
  61                                                                 w->info_rate = buffer[4] | (buffer[5] << 8) | (buffer[6] << 16) | (buffer[7] << 24);
  62                                                                 if (w->info_rate < 1)
  63                                                                 {
  64                                                                         error = "only rates 1hz-100khz supported\n";
  65                                                                         break;
  66                                                                 }
  67                                                                 w->info_bits = buffer[14] | (buffer[15] << 8);
  68                                                                 if (w->info_bits != 8 && w->info_bits != 16)
  69                                                                 {
  70                                                                         error = "only 8bit and 16bit supported\n";
  71                                                                         break;
  72                                                                 }
  73                                                                 validfmt = 1;
  74                                                         }
  75                                                         else if (!memcmp(buffer, "data", 4))
  76                                                         {
  77                                                                 if (validfmt)
  78                                                                 {
  79                                                                         w->datalength = length;
  80                                                                         w->dataposition = position;
  81                                                                 }
  82                                                         }
  83                                                         // other chunks that might be of interest:
  84                                                         // "cue " (for looping)
  85                                                         if (fseek(w->file, position + length, SEEK_SET))
  86                                                         {
  87                                                                 error = "error seeking to next chunk\n";
  88                                                                 break;
  89                                                         }
  90                                                 }
  91                                                 if (w->datalength && validfmt)
  92                                                 {
  93                                                         w->info_bytesperchannel = w->info_bits / 8;
  94                                                         w->info_bytespersample = w->info_channels * w->info_bytesperchannel;
  95                                                         w->length = w->datalength / w->info_bytespersample;
  96                                                         w->position = 0;
  97                                                         fseek(w->file, w->dataposition, SEEK_SET);
  98                                                         return w;
  99                                                 }
 100                                         }
 101                                         else
 102                                                 error = "not a RIFF WAVE file\n";
 103                                 }
 104                                 else
 105                                         error = "not a RIFF file\n";
 106                         }
 107                         else
 108                                 error = "error reading file\n";
 109                         free(w);
 110                 }
 111                 else
 112                         error = "unable to allocate memory\n";
 113                 fclose(file);
 114         }
 115         else
 116                 error = "unable to open file\n";
 117         if (errorstring)
 118                 *errorstring = error;
 119         return NULL;
 120 }
 121
 122 void waveclose(wavefile_t *f)
 123 {
 124         if (f)
 125         {
 126                 fclose(f->file);
 127                 free(f);
 128         }
 129 }
 130
 131 unsigned int waveread16stereo(wavefile_t *w, short *soundbuffer, unsigned int samples)
 132 {
 133         int i;
 134         int length;
 135         unsigned char *in;
 136         short *out;
 137         length = samples;
 138         if (length > w->length - w->position)
 139                 length = w->length - w->position;
 140         if (w->bufferlength < length)
 141         {
 142                 if (w->buffer)
 143                         free(w->buffer);
 144                 w->bufferlength = length + 100;
 145                 w->buffer = malloc(w->bufferlength * w->info_bytespersample);
 146         }
 147         length = fread(w->buffer, w->info_bytespersample, length, w->file);
 148         w->position += length;
 149         if (length > 0)
 150         {
 151                 if (w->info_bytesperchannel == 2)
 152                 {
 153                         if (w->info_channels == 2)
 154                         {
 155                                 for (i = 0, in = w->buffer, out = soundbuffer;i < length;i++, in += 4, out += 2)
 156                                 {
 157                                         out[0] = in[0] | (in[1] << 8);
 158                                         out[1] = in[2] | (in[3] << 8);
 159                                 }
 160                         }
 161                         else
 162                                 for (i = 0, in = w->buffer, out = soundbuffer;i < length;i++, in += 2, out += 2)
 163                                         out[0] = out[1] = in[0] | (in[1] << 8);
 164                 }
 165                 else
 166                 {
 167                         if (w->info_channels == 2)
 168                         {
 169                                 for (i = 0, in = w->buffer, out = soundbuffer;i < length;i++, in += 2, out += 2)
 170                                 {
 171                                         out[0] = (in[0] - 128) << 8;
 172                                         out[1] = (in[1] - 128) << 8;
 173                                 }
 174                         }
 175                         else
 176                                 for (i = 0, in = w->buffer, out = soundbuffer;i < length;i++, in += 1, out += 2)
 177                                         out[0] = out[1] = (in[0] - 128) << 8;
 178                 }
 179         }
 180         return length;
 181 }
 182
 183 unsigned int waveseek(wavefile_t *w, unsigned int samples)
 184 {
 185         if (samples > w->datalength)
 186                 return 1;
 187         else
 188         {
 189                 w->position = samples;
 190                 fseek(w->file, w->dataposition + w->position * w->info_bytespersample, SEEK_SET);
 191                 return 0;
 192         }
 193 }