test/wavwriter.c

   1 /* ------------------------------------------------------------------
   2  * Copyright (C) 2009 Martin Storsjo
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
  13  * express or implied.
  14  * See the License for the specific language governing permissions
  15  * and limitations under the License.
  16  * -------------------------------------------------------------------
  17  */
  18
  19 #include "wavwriter.h"
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include <stdlib.h>
  23 #include <stdint.h>
  24
  25 struct wav_writer {
  26         FILE *wav;
  27         int data_length;
  28
  29         int sample_rate;
  30         int bits_per_sample;
  31         int channels;
  32 };
  33
  34 static void write_string(struct wav_writer* ww, const char *str) {
  35         fputc(str[0], ww->wav);
  36         fputc(str[1], ww->wav);
  37         fputc(str[2], ww->wav);
  38         fputc(str[3], ww->wav);
  39 }
  40
  41 static void write_int32(struct wav_writer* ww, int value) {
  42         fputc((value >>  0) & 0xff, ww->wav);
  43         fputc((value >>  8) & 0xff, ww->wav);
  44         fputc((value >> 16) & 0xff, ww->wav);
  45         fputc((value >> 24) & 0xff, ww->wav);
  46 }
  47
  48 static void write_int16(struct wav_writer* ww, int value) {
  49         fputc((value >> 0) & 0xff, ww->wav);
  50         fputc((value >> 8) & 0xff, ww->wav);
  51 }
  52
  53 static void write_header(struct wav_writer* ww, int length) {
  54         int bytes_per_frame, bytes_per_sec;
  55         write_string(ww, "RIFF");
  56         write_int32(ww, 4 + 8 + 16 + 8 + length);
  57         write_string(ww, "WAVE");
  58
  59         write_string(ww, "fmt ");
  60         write_int32(ww, 16);
  61
  62         bytes_per_frame = ww->bits_per_sample/8*ww->channels;
  63         bytes_per_sec   = bytes_per_frame*ww->sample_rate;
  64         write_int16(ww, 1);                   // Format
  65         write_int16(ww, ww->channels);        // Channels
  66         write_int32(ww, ww->sample_rate);     // Samplerate
  67         write_int32(ww, bytes_per_sec);       // Bytes per sec
  68         write_int16(ww, bytes_per_frame);     // Bytes per frame
  69         write_int16(ww, ww->bits_per_sample); // Bits per sample
  70
  71         write_string(ww, "data");
  72         write_int32(ww, length);
  73 }
  74
  75 void* wav_write_open(const char *filename, int sample_rate, int bits_per_sample, int channels) {
  76         struct wav_writer* ww = (struct wav_writer*) malloc(sizeof(*ww));
  77         memset(ww, 0, sizeof(*ww));
  78         ww->wav = fopen(filename, "wb");
  79         if (ww->wav == NULL) {
  80                 free(ww);
  81                 return NULL;
  82         }
  83         ww->data_length = 0;
  84         ww->sample_rate = sample_rate;
  85         ww->bits_per_sample = bits_per_sample;
  86         ww->channels = channels;
  87
  88         write_header(ww, ww->data_length);
  89         return ww;
  90 }
  91
  92 void wav_write_close(void* obj) {
  93         struct wav_writer* ww = (struct wav_writer*) obj;
  94         if (ww->wav == NULL) {
  95                 free(ww);
  96                 return;
  97         }
  98         fseek(ww->wav, 0, SEEK_SET);
  99         write_header(ww, ww->data_length);
 100         fclose(ww->wav);
 101         free(ww);
 102 }
 103
 104 void wav_write_data(void* obj, const unsigned char* data, int length) {
 105         struct wav_writer* ww = (struct wav_writer*) obj;
 106         if (ww->wav == NULL)
 107                 return;
 108         fwrite(data, length, 1, ww->wav);
 109         ww->data_length += length;
 110 }
 111