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/* ------------------------------------------------------------------
* Copyright (C) 2009 Martin Storsjo
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied.
* See the License for the specific language governing permissions
* and limitations under the License.
* -------------------------------------------------------------------
*/
#include "wavreader.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#define TAG(a, b, c, d) (((a) << 24) | ((b) << 16) | ((c) << 8) | (d))
struct wav_reader {
FILE *wav;
uint32_t data_length;
int format;
int sample_rate;
int bits_per_sample;
int channels;
int byte_rate;
int block_align;
int streamed;
};
static uint32_t read_tag(struct wav_reader* wr) {
uint32_t tag = 0;
tag = (tag << 8) | fgetc(wr->wav);
tag = (tag << 8) | fgetc(wr->wav);
tag = (tag << 8) | fgetc(wr->wav);
tag = (tag << 8) | fgetc(wr->wav);
return tag;
}
static uint32_t read_int32(struct wav_reader* wr) {
uint32_t value = 0;
value |= fgetc(wr->wav) << 0;
value |= fgetc(wr->wav) << 8;
value |= fgetc(wr->wav) << 16;
value |= fgetc(wr->wav) << 24;
return value;
}
static uint16_t read_int16(struct wav_reader* wr) {
uint16_t value = 0;
value |= fgetc(wr->wav) << 0;
value |= fgetc(wr->wav) << 8;
return value;
}
static void skip(FILE *f, int n) {
int i;
for (i = 0; i < n; i++)
fgetc(f);
}
void* wav_read_open(const char *filename) {
struct wav_reader* wr = (struct wav_reader*) malloc(sizeof(*wr));
long data_pos = 0;
memset(wr, 0, sizeof(*wr));
if (!strcmp(filename, "-"))
wr->wav = stdin;
else
wr->wav = fopen(filename, "rb");
if (wr->wav == NULL) {
free(wr);
return NULL;
}
while (1) {
uint32_t tag, tag2, length;
tag = read_tag(wr);
if (feof(wr->wav))
break;
length = read_int32(wr);
if (!length || length >= 0x7fff0000) {
wr->streamed = 1;
length = ~0;
}
if (tag != TAG('R', 'I', 'F', 'F') || length < 4) {
fseek(wr->wav, length, SEEK_CUR);
continue;
}
tag2 = read_tag(wr);
length -= 4;
if (tag2 != TAG('W', 'A', 'V', 'E')) {
fseek(wr->wav, length, SEEK_CUR);
continue;
}
// RIFF chunk found, iterate through it
while (length >= 8) {
uint32_t subtag, sublength;
subtag = read_tag(wr);
if (feof(wr->wav))
break;
sublength = read_int32(wr);
length -= 8;
if (length < sublength)
break;
if (subtag == TAG('f', 'm', 't', ' ')) {
if (sublength < 16) {
// Insufficient data for 'fmt '
break;
}
wr->format = read_int16(wr);
wr->channels = read_int16(wr);
wr->sample_rate = read_int32(wr);
wr->byte_rate = read_int32(wr);
wr->block_align = read_int16(wr);
wr->bits_per_sample = read_int16(wr);
skip(wr->wav, sublength - 16);
} else if (subtag == TAG('d', 'a', 't', 'a')) {
data_pos = ftell(wr->wav);
wr->data_length = sublength;
if (!wr->data_length || wr->streamed) {
wr->streamed = 1;
return wr;
}
fseek(wr->wav, sublength, SEEK_CUR);
} else {
skip(wr->wav, sublength);
}
length -= sublength;
}
if (length > 0) {
// Bad chunk?
fseek(wr->wav, length, SEEK_CUR);
}
}
fseek(wr->wav, data_pos, SEEK_SET);
return wr;
}
void wav_read_close(void* obj) {
struct wav_reader* wr = (struct wav_reader*) obj;
if (wr->wav != stdin)
fclose(wr->wav);
free(wr);
}
int wav_get_header(void* obj, int* format, int* channels, int* sample_rate, int* bits_per_sample, unsigned int* data_length) {
struct wav_reader* wr = (struct wav_reader*) obj;
if (format)
*format = wr->format;
if (channels)
*channels = wr->channels;
if (sample_rate)
*sample_rate = wr->sample_rate;
if (bits_per_sample)
*bits_per_sample = wr->bits_per_sample;
if (data_length)
*data_length = wr->data_length;
return wr->format && wr->sample_rate;
}
int wav_read_data(void* obj, unsigned char* data, unsigned int length) {
struct wav_reader* wr = (struct wav_reader*) obj;
int n;
if (wr->wav == NULL)
return -1;
if (length > wr->data_length && !wr->streamed)
length = wr->data_length;
n = fread(data, 1, length, wr->wav);
wr->data_length -= length;
return n;
}
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