FreeCalypso > hg > gsm-codec-lib
view libtest/wavreader.c @ 216:9d59df9b0e4e
amrconv: new program amr-ietf2cod
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Fri, 21 Apr 2023 21:28:02 +0000 |
parents | 634df6435e16 |
children |
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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; }; 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; }