diff options
Diffstat (limited to 'wavreader.c')
| -rw-r--r-- | wavreader.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/wavreader.c b/wavreader.c new file mode 100644 index 0000000..f672001 --- /dev/null +++ b/wavreader.c @@ -0,0 +1,163 @@ +/* ------------------------------------------------------------------ + * 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; +}; + +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; +} + +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)); + + 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 (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); + fseek(wr->wav, sublength - 16, SEEK_CUR); + } else if (subtag == TAG('d', 'a', 't', 'a')) { + data_pos = ftell(wr->wav); + wr->data_length = sublength; + fseek(wr->wav, sublength, SEEK_CUR); + } else { + fseek(wr->wav, sublength, SEEK_CUR); + } + 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; + 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) + length = wr->data_length; + n = fread(data, 1, length, wr->wav); + wr->data_length -= length; + return n; +} + |