format_wav.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Work with WAV in the proprietary Microsoft format.
 * Microsoft WAV format (8000hz Signed Linear)
 * \arg File name extension: wav (lower case)
 * \ingroup formats
 */

/*** MODULEINFO
 <support_level>core</support_level>
 ***/

#include "asterisk.h"

#include "asterisk/mod_format.h"
#include "asterisk/module.h"
#include "asterisk/endian.h"
#include "asterisk/format_cache.h"
#include "asterisk/format.h"
#include "asterisk/codec.h"

/* Some Ideas for this code came from makewave.c by Jeffrey Chilton */

/* Portions of the conversion code are by [email protected] */

#define WAV_BUF_SIZE 320

#define WAV_HEADER_SIZE 44

struct wav_desc { /* format-specific parameters */
 int hz;
 int bytes;
 int lasttimeout;
 int maxlen;
 struct timeval last;
};

#define BLOCKSIZE 160

#if __BYTE_ORDER == __LITTLE_ENDIAN
#define htoll(b) (b)
#define htols(b) (b)
#define ltohl(b) (b)
#define ltohs(b) (b)
#else
#if __BYTE_ORDER == __BIG_ENDIAN
#define htoll(b) \
 (((((b) ) & 0xFF) << 24) | \
 ((( (b) >> 8) & 0xFF) << 16) | \
 ((( (b) >> 16) & 0xFF) << 8) | \
 ((( (b) >> 24) & 0xFF) ))
#define htols(b) \
 (((((b) ) & 0xFF) << 8) | \
 ((( (b) >> 8) & 0xFF) ))
#define ltohl(b) htoll(b)
#define ltohs(b) htols(b)
#else
#error "Endianess not defined"
#endif
#endif


static int check_header_fmt(FILE *f, int hsize, int hz)
{
 unsigned short format, chans, bysam, bisam;
 unsigned int freq, bysec;
 if (hsize < 16) {
 ast_log(LOG_WARNING, "Unexpected header size %d\n", hsize);
 return -1;
 }
 if (fread(&format, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Read failed (format)\n");
 return -1;
 }
 if (ltohs(format) != 1) {
 ast_log(LOG_WARNING, "Not a supported wav file format (%d). Only PCM encoded, 16 bit, mono, 8kHz/16kHz files are supported with a lowercase '.wav' extension.\n", ltohs(format));
 return -1;
 }
 if (fread(&chans, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Read failed (format)\n");
 return -1;
 }
 if (ltohs(chans) != 1) {
 ast_log(LOG_WARNING, "Not in mono %d\n", ltohs(chans));
 return -1;
 }
 if (fread(&freq, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (freq)\n");
 return -1;
 }
 freq = ltohl(freq);
 if ((freq != 8000 && freq != 16000) || freq != hz) {
 ast_log(LOG_WARNING, "Unexpected frequency mismatch %d (expecting %d)\n", freq, hz);
 return -1;
 }
 /* Ignore the byte frequency */
 if (fread(&bysec, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (BYTES_PER_SECOND)\n");
 return -1;
 }
 /* Check bytes per sample */
 if (fread(&bysam, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Read failed (BYTES_PER_SAMPLE)\n");
 return -1;
 }
 if (ltohs(bysam) != 2) {
 ast_log(LOG_WARNING, "Can only handle 16bits per sample: %d\n", ltohs(bysam));
 return -1;
 }
 if (fread(&bisam, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Read failed (Bits Per Sample): %d\n", ltohs(bisam));
 return -1;
 }
 /* Skip any additional header */
 if (fseek(f,hsize-16,SEEK_CUR) == -1 ) {
 ast_log(LOG_WARNING, "Failed to skip remaining header bytes: %d\n", hsize-16 );
 return -1;
 }
 return 0;
}

static int check_header(FILE *f, int hz)
{
 int type, size, formtype;
 int data;
 if (fread(&type, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (type)\n");
 return -1;
 }
 if (fread(&size, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (size)\n");
 return -1;
 }
#if __BYTE_ORDER == __BIG_ENDIAN
 size = ltohl(size);
#endif
 if (fread(&formtype, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (formtype)\n");
 return -1;
 }
 if (memcmp(&type, "RIFF", 4)) {
 ast_log(LOG_WARNING, "Does not begin with RIFF\n");
 return -1;
 }
 if (memcmp(&formtype, "WAVE", 4)) {
 ast_log(LOG_WARNING, "Does not contain WAVE\n");
 return -1;
 }
 /* Skip any facts and get the first data block */
 for(;;)
 {
 char buf[4];

 /* Begin data chunk */
 if (fread(&buf, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (block header format)\n");
 return -1;
 }
 /* Data has the actual length of data in it */
 if (fread(&data, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (block '%.4s' header length)\n", buf);
 return -1;
 }
#if __BYTE_ORDER == __BIG_ENDIAN
 data = ltohl(data);
#endif
 if (memcmp(&buf, "fmt ", 4) == 0) {
 if (check_header_fmt(f, data, hz))
 return -1;
 continue;
 }
 if(memcmp(buf, "data", 4) == 0 )
 break;
 ast_log(LOG_DEBUG, "Skipping unknown block '%.4s'\n", buf);
 if (fseek(f,data,SEEK_CUR) == -1 ) {
 ast_log(LOG_WARNING, "Failed to skip '%.4s' block: %d\n", buf, data);
 return -1;
 }
 }
#if 0
 curpos = lseek(fd, 0, SEEK_CUR);
 truelength = lseek(fd, 0, SEEK_END);
 lseek(fd, curpos, SEEK_SET);
 truelength -= curpos;
#endif
 return data;
}

static int update_header(FILE *f)
{
 off_t cur,end;
 int datalen,filelen,bytes;

 cur = ftello(f);
 fseek(f, 0, SEEK_END);
 end = ftello(f);
 /* data starts 44 bytes in */
 bytes = end - 44;
 datalen = htoll(bytes);
 /* chunk size is bytes of data plus 36 bytes of header */
 filelen = htoll(36 + bytes);

 if (cur < 0) {
 ast_log(LOG_WARNING, "Unable to find our position\n");
 return -1;
 }
 if (fseek(f, 4, SEEK_SET)) {
 ast_log(LOG_WARNING, "Unable to set our position\n");
 return -1;
 }
 if (fwrite(&filelen, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to set write file size\n");
 return -1;
 }
 if (fseek(f, 40, SEEK_SET)) {
 ast_log(LOG_WARNING, "Unable to set our position\n");
 return -1;
 }
 if (fwrite(&datalen, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to set write datalen\n");
 return -1;
 }
 if (fseeko(f, cur, SEEK_SET)) {
 ast_log(LOG_WARNING, "Unable to return to position\n");
 return -1;
 }
 return 0;
}

static int write_header(FILE *f, int writehz)
{
 unsigned int hz;
 unsigned int bhz;
 unsigned int hs = htoll(16);
 unsigned short fmt = htols(1);
 unsigned short chans = htols(1);
 unsigned short bysam = htols(2);
 unsigned short bisam = htols(16);
 unsigned int size = htoll(0);

 if (writehz == 16000) {
 hz = htoll(16000);
 bhz = htoll(32000);
 } else {
 hz = htoll(8000);
 bhz = htoll(16000);
 }
 /* Write a wav header, ignoring sizes which will be filled in later */
 fseek(f,0,SEEK_SET);
 if (fwrite("RIFF", 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 if (fwrite(&size, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 if (fwrite("WAVEfmt ", 1, 8, f) != 8) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 if (fwrite(&hs, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 if (fwrite(&fmt, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 if (fwrite(&chans, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 if (fwrite(&hz, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 if (fwrite(&bhz, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 if (fwrite(&bysam, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 if (fwrite(&bisam, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 if (fwrite("data", 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 if (fwrite(&size, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 return 0;
}

static int wav_open(struct ast_filestream *s)
{
 /* We don't have any header to read or anything really, but
 if we did, it would go here. We also might want to check
 and be sure it's a valid file. */
 struct wav_desc *tmp = s->_private;
 unsigned int sample_rate = ast_format_get_sample_rate(s->fmt->format);

 tmp->maxlen = check_header(s->f, sample_rate);
 if (tmp->maxlen < 0) {
 return -1;
 }

 tmp->hz = sample_rate;
 return 0;
}

static int wav_rewrite(struct ast_filestream *s, const char *comment)
{
 /* We don't have any header to read or anything really, but
 if we did, it would go here. We also might want to check
 and be sure it's a valid file. */

 struct wav_desc *tmp = (struct wav_desc *)s->_private;
 tmp->hz = ast_format_get_sample_rate(s->fmt->format);
 if (write_header(s->f,tmp->hz))
 return -1;
 return 0;
}

static void wav_close(struct ast_filestream *s)
{
 char zero = 0;
 struct wav_desc *fs = (struct wav_desc *)s->_private;

 if (s->mode == O_RDONLY) {
 return;
 }

 if (s->filename) {
 update_header(s->f);
 }

 /* Pad to even length */
 if (fs->bytes & 0x1) {
 if (fwrite(&zero, 1, 1, s->f) != 1) {
 ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
 }
 }
}

static struct ast_frame *wav_read(struct ast_filestream *s, int *whennext)
{
 size_t res;
 int samples; /* actual samples read */
#if __BYTE_ORDER == __BIG_ENDIAN
 int x;
 short *tmp;
#endif
 int bytes;
 off_t here;
 /* Send a frame from the file to the appropriate channel */
 struct wav_desc *fs = (struct wav_desc *)s->_private;

 bytes = (fs->hz == 16000 ? (WAV_BUF_SIZE * 2) : WAV_BUF_SIZE);

 here = ftello(s->f);
 if (fs->maxlen - here < bytes) /* truncate if necessary */
 bytes = fs->maxlen - here;
 if (bytes <= 0) {
 return NULL;
 }
/* ast_debug(1, "here: %d, maxlen: %d, bytes: %d\n", here, s->maxlen, bytes); */
 AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, bytes);

 if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) == 0) {
 if (res) {
 ast_log(LOG_WARNING, "Short read of %s data (expected %d bytes, read %zu): %s\n",
 ast_format_get_name(s->fr.subclass.format), s->fr.datalen, res,
 strerror(errno));
 }
 return NULL;
 }
 s->fr.datalen = res;
 s->fr.samples = samples = res / 2;

#if __BYTE_ORDER == __BIG_ENDIAN
 tmp = (short *)(s->fr.data.ptr);
 /* file format is little endian so we need to swap */
 for( x = 0; x < samples; x++)
 tmp[x] = (tmp[x] << 8) | ((tmp[x] & 0xff00) >> 8);
#endif

 *whennext = samples;
 return &s->fr;
}

static int wav_write(struct ast_filestream *fs, struct ast_frame *f)
{
#if __BYTE_ORDER == __BIG_ENDIAN
 int x;
 short tmp[16000], *tmpi;
#endif
 struct wav_desc *s = (struct wav_desc *)fs->_private;
 int res;

 if (!f->datalen)
 return -1;

#if __BYTE_ORDER == __BIG_ENDIAN
 /* swap and write */
 if (f->datalen > sizeof(tmp)) {
 ast_log(LOG_WARNING, "Data length is too long\n");
 return -1;
 }
 tmpi = f->data.ptr;
 for (x=0; x < f->datalen/2; x++)
 tmp[x] = (tmpi[x] << 8) | ((tmpi[x] & 0xff00) >> 8);

 if ((res = fwrite(tmp, 1, f->datalen, fs->f)) != f->datalen ) {
#else
 /* just write */
 if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen ) {
#endif
 ast_log(LOG_WARNING, "Bad write (%d): %s\n", res, strerror(errno));
 return -1;
 }

 s->bytes += f->datalen;

 return 0;

}

static int wav_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
{
 off_t min = WAV_HEADER_SIZE, max, cur, offset = 0, samples;

 samples = sample_offset * 2; /* SLINEAR is 16 bits mono, so sample_offset * 2 = bytes */

 if ((cur = ftello(fs->f)) < 0) {
 ast_log(AST_LOG_WARNING, "Unable to determine current position in wav filestream %p: %s\n", fs, strerror(errno));
 return -1;
 }

 if (fseeko(fs->f, 0, SEEK_END) < 0) {
 ast_log(AST_LOG_WARNING, "Unable to seek to end of wav filestream %p: %s\n", fs, strerror(errno));
 return -1;
 }

 if ((max = ftello(fs->f)) < 0) {
 ast_log(AST_LOG_WARNING, "Unable to determine max position in wav filestream %p: %s\n", fs, strerror(errno));
 return -1;
 }

 if (whence == SEEK_SET) {
 offset = samples + min;
 } else if (whence == SEEK_CUR || whence == SEEK_FORCECUR) {
 offset = samples + cur;
 } else if (whence == SEEK_END) {
 offset = max - samples;
 }
 if (whence != SEEK_FORCECUR) {
 offset = (offset > max)?max:offset;
 }
 /* always protect the header space. */
 offset = (offset < min)?min:offset;
 return fseeko(fs->f, offset, SEEK_SET);
}

static int wav_trunc(struct ast_filestream *fs)
{
 int fd;
 off_t cur;

 if ((fd = fileno(fs->f)) < 0) {
 ast_log(AST_LOG_WARNING, "Unable to determine file descriptor for wav filestream %p: %s\n", fs, strerror(errno));
 return -1;
 }
 if ((cur = ftello(fs->f)) < 0) {
 ast_log(AST_LOG_WARNING, "Unable to determine current position in wav filestream %p: %s\n", fs, strerror(errno));
 return -1;
 }
 /* Truncate file to current length */
 if (ftruncate(fd, cur)) {
 return -1;
 }
 return update_header(fs->f);
}

static off_t wav_tell(struct ast_filestream *fs)
{
 off_t offset;
 offset = ftello(fs->f);
 /* subtract header size to get samples, then divide by 2 for 16 bit samples */
 return (offset - 44)/2;
}

static struct ast_format_def wav16_f = {
 .name = "wav16",
 .exts = "wav16",
 .mime_types = "audio/x-wav;codec=pcm;bit=16;rate=16000",
 .open = wav_open,
 .rewrite = wav_rewrite,
 .write = wav_write,
 .seek = wav_seek,
 .trunc = wav_trunc,
 .tell = wav_tell,
 .read = wav_read,
 .close = wav_close,
 .buf_size = (WAV_BUF_SIZE * 2) + AST_FRIENDLY_OFFSET,
 .desc_size = sizeof(struct wav_desc),
};

static struct ast_format_def wav_f = {
 .name = "wav",
 .exts = "wav",
 .mime_types = "audio/wav|audio/x-wav|audio/x-wav;codec=pcm;bit=16;rate=8000",
 .open = wav_open,
 .rewrite = wav_rewrite,
 .write = wav_write,
 .seek = wav_seek,
 .trunc = wav_trunc,
 .tell = wav_tell,
 .read = wav_read,
 .close = wav_close,
 .buf_size = WAV_BUF_SIZE + AST_FRIENDLY_OFFSET,
 .desc_size = sizeof(struct wav_desc),
};

static int unload_module(void)
{
 return ast_format_def_unregister(wav_f.name)
 || ast_format_def_unregister(wav16_f.name);
}

static int load_module(void)
{
 wav_f.format = ast_format_slin;
 wav16_f.format = ast_format_slin16;
 if (ast_format_def_register(&wav_f)
 || ast_format_def_register(&wav16_f)) {
 unload_module();
 return AST_MODULE_LOAD_DECLINE;
 }
 return AST_MODULE_LOAD_SUCCESS;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Microsoft WAV/WAV16 format (8kHz/16kHz Signed Linear)",
 .support_level = AST_MODULE_SUPPORT_CORE,
 .load = load_module,
 .unload = unload_module,
 .load_pri = AST_MODPRI_APP_DEPEND
);