+++ /dev/null
-/*
- * This file is part of DisOrder
- * Copyright (C) 2007 Richard Kettlewell
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-/** @file lib/wav.c
- * @brief WAV file support
- *
- * This is used by the WAV file suppoort in the tracklength plugin and
- * by disorder-decode (see @ref server/decode.c).
- */
-
-/* Sources:
- *
- * http://www.technology.niagarac.on.ca/courses/comp530/WavFileFormat.html
- * http://www.borg.com/~jglatt/tech/wave.htm
- * http://www.borg.com/~jglatt/tech/aboutiff.htm
- *
- * These files consists of a header followed by chunks.
- * Multibyte values are little-endian.
- *
- * 12 byte file header:
- * offset size meaning
- * 00 4 'RIFF'
- * 04 4 length of rest of file
- * 08 4 'WAVE'
- *
- * The length includes 'WAVE' but excludes the 1st 8 bytes.
- *
- * Chunk header:
- * 00 4 chunk ID
- * 04 4 length of rest of chunk
- *
- * The stated length may be odd, if so then there is an implicit padding byte
- * appended to the chunk to make it up to an even length (someone wasn't
- * think about 32/64-bit worlds).
- *
- * Also some files seem to have extra stuff at the end of chunks that nobody
- * I know of documents. Go figure, but check the length field rather than
- * deducing the length from the ID.
- *
- * Format chunk:
- * 00 4 'fmt'
- * 04 4 length of rest of chunk
- * 08 2 compression (1 = none)
- * 0a 2 number of channels
- * 0c 4 samples/second
- * 10 4 average bytes/second, = (samples/sec) * (bytes/sample)
- * 14 2 bytes/sample
- * 16 2 bits/sample point
- *
- * 'sample' means 'sample frame' above, i.e. a sample point for each channel.
- *
- * Data chunk:
- * 00 4 'data'
- * 04 4 length of rest of chunk
- * 08 ... data
- *
- * There is only allowed to be one data chunk. Some people violate this; we
- * shall encourage people to fix their broken WAV files by not supporting
- * this violation and because it's easier.
- *
- * As to the encoding of the data:
- *
- * Firstly, samples up to 8 bits in size are unsigned, larger samples are
- * signed. Madness.
- *
- * Secondly sample points are stored rounded up to a multiple of 8 bits in
- * size. Marginally saner.
- *
- * Written as a single word (of 8, 16, 24, whatever bits) the padding to
- * implement this happens at the right hand (least significant) end.
- * e.g. assuming a 9 bit sample:
- *
- * | padded sample word |
- * | 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 |
- * | 8 7 6 5 4 3 2 1 0 - - - - - - - |
- *
- * But this is a little-endian file format so the least significant byte is
- * the first, which means that the padding is "between" the bits if you
- * imagine them in their usual order:
- *
- * | first byte | second byte |
- * | 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 |
- * | 0 - - - - - - - | 8 7 6 5 4 3 2 1 |
- *
- * Sample points are grouped into sample frames, consisting of as many
- * samples points as their are channels. It seems that there are standard
- * orderings of different channels.
- */
-
-#include "common.h"
-
-#include <unistd.h>
-#include <fcntl.h>
-#include <errno.h>
-
-#include "log.h"
-#include "wav.h"
-
-static inline uint16_t get16(const char *ptr) {
- return (uint8_t)ptr[0] + 256 * (uint8_t)ptr[1];
-}
-
-static inline uint32_t get32(const char *ptr) {
- return (uint8_t)ptr[0] + 256 * (uint8_t)ptr[1]
- + 65536 * (uint8_t)ptr[2] + 16777216 * (uint8_t)ptr[3];
-}
-
-/** @brief Open a WAV file
- * @return 0 on success, an errno value on error
- */
-int wav_init(struct wavfile *f, const char *path) {
- int err, n;
- char header[64];
- off_t where;
-
- memset(f, 0, sizeof *f);
- f->data = -1;
- if(hreader_init(path, f->input)) goto error_errno;
- /* Read the file header
- *
- * offset size meaning
- * 00 4 'RIFF'
- * 04 4 length of rest of file
- * 08 4 'WAVE'
- * */
- if((n = hreader_pread(f->input, header, 12, 0)) < 0) goto error_errno;
- else if(n < 12) goto einval;
- if(strncmp(header, "RIFF", 4) || strncmp(header + 8, "WAVE", 4))
- goto einval;
- f->length = 8 + get32(header + 4);
- /* Visit all the chunks */
- for(where = 12; where + 8 <= f->length;) {
- /* Read the chunk header
- *
- * offset size meaning
- * 00 4 chunk ID
- * 04 4 length of rest of chunk
- */
- if((n = hreader_pread(f->input, header, 8, where)) < 0) goto error_errno;
- else if(n < 8) goto einval;
- if(!strncmp(header,"fmt ", 4)) {
- /* This is the format chunk
- *
- * offset size meaning
- * 00 4 'fmt'
- * 04 4 length of rest of chunk
- * 08 2 compression (1 = none)
- * 0a 2 number of channels
- * 0c 4 samples/second
- * 10 4 average bytes/second, = (samples/sec) * (bytes/sample)
- * 14 2 bytes/sample
- * 16 2 bits/sample point
- * 18 ? extra undocumented rubbish
- */
- if(get32(header + 4) < 16) goto einval;
- if((n = hreader_pread(f->input, header + 8, 16, where + 8)) < 0)
- goto error_errno;
- else if(n < 16) goto einval;
- f->channels = get16(header + 0x0A);
- f->rate = get32(header + 0x0C);
- f->bits = get16(header + 0x16);
- } else if(!strncmp(header, "data", 4)) {
- /* Remember where the data chunk was and how big it is */
- f->data = where;
- f->datasize = get32(header + 4);
- }
- where += 8 + get32(header + 4);
- }
- /* There had better have been a format chunk */
- if(f->rate == 0) goto einval;
- /* There had better have been a data chunk */
- if(f->data == -1) goto einval;
- return 0;
-einval:
- err = EINVAL;
- goto error;
-error_errno:
- err = errno;
-error:
- wav_destroy(f);
- return err;
-}
-
-/** @brief Close a WAV file */
-void wav_destroy(struct wavfile *f) {
- hreader_close(f->input);
-}
-
-/** @brief Visit all the data in a WAV file
- * @param f WAV file handle
- * @param callback Called for successive blocks of data
- * @param u User data
- *
- * @p callback will only ever be passed whole frames.
- */
-int wav_data(struct wavfile *f,
- wav_data_callback *callback,
- void *u) {
- off_t left = f->datasize;
- off_t where = f->data + 8;
- char buffer[4096];
- int err;
- ssize_t n;
- const size_t bytes_per_frame = f->channels * ((f->bits + 7) / 8);
-
- while(left > 0) {
- size_t want = (off_t)sizeof buffer > left ? (size_t)left : sizeof buffer;
-
- want -= want % bytes_per_frame;
- if((n = hreader_pread(f->input, buffer, want, where)) < 0) return errno;
- if((size_t)n < want) return EINVAL;
- if((err = callback(f, buffer, n, u))) return err;
- where += n;
- left -= n;
- }
- return 0;
-}
-
-/*
-Local Variables:
-c-basic-offset:2
-comment-column:40
-fill-column:79
-indent-tabs-mode:nil
-End:
-*/
~mdw / disorder / blobdiff