wavefile.c

   1
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include <string.h>
   5 #include "wavefile.h"
   6
   7 wavefile_t *waveopen(char *filename, char **errorstring)
   8 {
   9         int validfmt, position, length, l;
  10         char *error;
  11         wavefile_t *w;
  12         FILE *file;
  13         unsigned char buffer[1024];
  14         error = NULL;
  15         file = fopen(filename, "rb");
  16         if (file)
  17         {
  18                 w = malloc(sizeof(*w));
  19                 memset(w, 0, sizeof(*w));
  20                 if (w)
  21                 {
  22                         w->file = file;
  23                         if (fread(buffer, 12, 1, w->file))
  24                         {
  25                                 if (!memcmp(buffer, "RIFF", 4))
  26                                 {
  27                                         if (!memcmp(buffer + 8, "WAVE", 4))
  28                                         {
  29                                                 validfmt = 0;
  30                                                 for(;;)
  31                                                 {
  32                                                         if (!fread(buffer, 8, 1, w->file))
  33                                                         {
  34                                                                 //error = "error reading chunk\n");
  35                                                                 break;
  36                                                         }
  37                                                         position = ftell(w->file);
  38                                                         length = buffer[4] | (buffer[5] << 8) | (buffer[6] << 16) | (buffer[7] << 24);
  39                                                         if (!memcmp(buffer, "fmt ", 4))
  40                                                         {
  41                                                                 validfmt = 0;
  42                                                                 l = length;
  43                                                                 if (l > 16)
  44                                                                         l = 16;
  45                                                                 if (!fread(buffer, l, 1, w->file))
  46                                                                 {
  47                                                                         error = "error reading \"fmt \" chunk\n";
  48                                                                         break;
  49                                                                 }
  50                                                                 w->info_format = buffer[0] | (buffer[1] << 8);
  51                                                                 if (w->info_format != 1)
  52                                                                 {
  53                                                                         error = "only PCM format supported\n";
  54                                                                         break;
  55                                                                 }
  56                                                                 w->info_channels = buffer[2] | (buffer[3] << 8);
  57                                                                 if (w->info_channels != 1 && w->info_channels != 2)
  58                                                                 {
  59                                                                         error = "only mono and stereo supported\n";
  60                                                                         break;
  61                                                                 }
  62                                                                 w->info_rate = buffer[4] | (buffer[5] << 8) | (buffer[6] << 16) | (buffer[7] << 24);
  63                                                                 if (w->info_rate < 1)
  64                                                                 {
  65                                                                         error = "only rates 1hz-100khz supported\n";
  66                                                                         break;
  67                                                                 }
  68                                                                 w->info_bits = buffer[14] | (buffer[15] << 8);
  69                                                                 if (w->info_bits != 8 && w->info_bits != 16)
  70                                                                 {
  71                                                                         error = "only 8bit and 16bit supported\n";
  72                                                                         break;
  73                                                                 }
  74                                                                 validfmt = 1;
  75                                                         }
  76                                                         else if (!memcmp(buffer, "data", 4))
  77                                                         {
  78                                                                 if (validfmt)
  79                                                                 {
  80                                                                         w->datalength = length;
  81                                                                         w->dataposition = position;
  82                                                                 }
  83                                                         }
  84                                                         // other chunks that might be of interest:
  85                                                         // "cue " (for looping)
  86                                                         if (fseek(w->file, position + length, SEEK_SET))
  87                                                         {
  88                                                                 error = "error seeking to next chunk\n";
  89                                                                 break;
  90                                                         }
  91                                                 }
  92                                                 if (w->datalength && validfmt)
  93                                                 {
  94                                                         w->info_bytesperchannel = w->info_bits / 8;
  95                                                         w->info_bytespersample = w->info_channels * w->info_bytesperchannel;
  96                                                         w->length = w->datalength / w->info_bytespersample;
  97                                                         w->position = 0;
  98                                                         fseek(w->file, w->dataposition, SEEK_SET);
  99                                                         return w;
 100                                                 }
 101                                         }
 102                                         else
 103                                                 error = "not a RIFF WAVE file\n";
 104                                 }
 105                                 else
 106                                         error = "not a RIFF file\n";
 107                         }
 108                         else
 109                                 error = "error reading file\n";
 110                         free(w);
 111                 }
 112                 else
 113                         error = "unable to allocate memory\n";
 114                 fclose(file);
 115         }
 116         else
 117                 error = "unable to open file\n";
 118         if (errorstring)
 119                 *errorstring = error;
 120         return NULL;
 121 }
 122
 123 void waveclose(wavefile_t *f)
 124 {
 125         if (f)
 126         {
 127                 fclose(f->file);
 128                 free(f);
 129         }
 130 }
 131
 132 unsigned int waveread16stereo(wavefile_t *w, short *soundbuffer, unsigned int samples)
 133 {
 134         unsigned int i;
 135         unsigned int length;
 136         unsigned char *in;
 137         short *out;
 138         length = samples;
 139         if (length > w->length - w->position)
 140                 length = w->length - w->position;
 141         if (w->bufferlength < length)
 142         {
 143                 if (w->buffer)
 144                         free(w->buffer);
 145                 w->bufferlength = length + 100;
 146                 w->buffer = malloc(w->bufferlength * w->info_bytespersample);
 147         }
 148         length = fread(w->buffer, w->info_bytespersample, length, w->file);
 149         w->position += length;
 150         if (length > 0)
 151         {
 152                 if (w->info_bytesperchannel == 2)
 153                 {
 154                         if (w->info_channels == 2)
 155                         {
 156                                 for (i = 0, in = w->buffer, out = soundbuffer;i < length;i++, in += 4, out += 2)
 157                                 {
 158                                         out[0] = in[0] | (in[1] << 8);
 159                                         out[1] = in[2] | (in[3] << 8);
 160                                 }
 161                         }
 162                         else
 163                                 for (i = 0, in = w->buffer, out = soundbuffer;i < length;i++, in += 2, out += 2)
 164                                         out[0] = out[1] = in[0] | (in[1] << 8);
 165                 }
 166                 else
 167                 {
 168                         if (w->info_channels == 2)
 169                         {
 170                                 for (i = 0, in = w->buffer, out = soundbuffer;i < length;i++, in += 2, out += 2)
 171                                 {
 172                                         out[0] = (in[0] - 128) << 8;
 173                                         out[1] = (in[1] - 128) << 8;
 174                                 }
 175                         }
 176                         else
 177                                 for (i = 0, in = w->buffer, out = soundbuffer;i < length;i++, in += 1, out += 2)
 178                                         out[0] = out[1] = (in[0] - 128) << 8;
 179                 }
 180         }
 181         return length;
 182 }
 183
 184 unsigned int waveseek(wavefile_t *w, unsigned int samples)
 185 {
 186         if (samples > w->datalength)
 187                 return 1;
 188         else
 189         {
 190                 w->position = samples;
 191                 fseek(w->file, w->dataposition + w->position * w->info_bytespersample, SEEK_SET);
 192                 return 0;
 193         }
 194 }