format_wav_gsm.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 Save GSM in the proprietary Microsoft format.
 *
 * Microsoft WAV format (Proprietary GSM)
 * \arg File name extension: WAV,wav49 (Upper case WAV, lower case is another format)
 * This format can be played on Windows systems, used for
 * e-mail attachments mainly.
 * \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 "msgsm.h"

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

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

#define GSM_FRAME_SIZE 33
#define MSGSM_FRAME_SIZE 65
#define MSGSM_DATA_OFFSET 60 /* offset of data bytes */
#define GSM_SAMPLES 160 /* samples in a GSM block */
#define MSGSM_SAMPLES (2*GSM_SAMPLES) /* samples in an MSGSM block */

/* begin binary data: */
static char msgsm_silence[] = /* 65 */
{0x48,0x17,0xD6,0x84,0x02,0x80,0x24,0x49,0x92,0x24,0x89,0x02,0x80,0x24,0x49
,0x92,0x24,0x89,0x02,0x80,0x24,0x49,0x92,0x24,0x89,0x02,0x80,0x24,0x49,0x92
,0x24,0x09,0x82,0x74,0x61,0x4D,0x28,0x00,0x48,0x92,0x24,0x49,0x92,0x28,0x00
,0x48,0x92,0x24,0x49,0x92,0x28,0x00,0x48,0x92,0x24,0x49,0x92,0x28,0x00,0x48
,0x92,0x24,0x49,0x92,0x00};
/* end binary data. size = 65 bytes */

struct wavg_desc {
 /* Believe it or not, we must decode/recode to account for the
 weird MS format */
 int secondhalf; /* Are we on the second half */
};

#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(FILE *f)
{
 int type, size, formtype;
 int fmt, hsize, fact;
 short format, chans;
 int freq;
 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;
 }
 if (fread(&fmt, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (fmt)\n");
 return -1;
 }
 if (memcmp(&fmt, "fmt ", 4)) {
 ast_log(LOG_WARNING, "Does not say fmt\n");
 return -1;
 }
 if (fread(&hsize, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (formtype)\n");
 return -1;
 }
 if (ltohl(hsize) != 20) {
 ast_log(LOG_WARNING, "Unexpected header size %d\n", ltohl(hsize));
 return -1;
 }
 if (fread(&format, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Read failed (format)\n");
 return -1;
 }
 if (ltohs(format) != 49) {
 ast_log(LOG_WARNING, "Not a GSM file %d\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;
 }
 if (ltohl(freq) != DEFAULT_SAMPLE_RATE) {
 ast_log(LOG_WARNING, "Unexpected frequency %d\n", ltohl(freq));
 return -1;
 }
 /* Ignore the byte frequency */
 if (fread(&freq, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (X_1)\n");
 return -1;
 }
 /* Ignore the two weird fields */
 if (fread(&freq, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (X_2/X_3)\n");
 return -1;
 }
 /* Ignore the byte frequency */
 if (fread(&freq, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (Y_1)\n");
 return -1;
 }
 /* Check for the word fact */
 if (fread(&fact, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (fact)\n");
 return -1;
 }
 if (memcmp(&fact, "fact", 4)) {
 ast_log(LOG_WARNING, "Does not say fact\n");
 return -1;
 }
 /* Ignore the "fact value" */
 if (fread(&fact, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (fact header)\n");
 return -1;
 }
 if (fread(&fact, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (fact value)\n");
 return -1;
 }
 /* Check for the word data */
 if (fread(&data, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (data)\n");
 return -1;
 }
 if (memcmp(&data, "data", 4)) {
 ast_log(LOG_WARNING, "Does not say data\n");
 return -1;
 }
 /* Ignore the data length */
 if (fread(&data, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Read failed (data)\n");
 return -1;
 }
 return 0;
}

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

 cur = ftello(f);
 fseek(f, 0, SEEK_END);
 end = ftello(f);
 /* in a gsm WAV, data starts 60 bytes in */
 bytes = end - MSGSM_DATA_OFFSET;
 samples = htoll(bytes / MSGSM_FRAME_SIZE * MSGSM_SAMPLES);
 datalen = htoll(bytes);
 filelen = htoll(MSGSM_DATA_OFFSET - 8 + 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 write file size\n");
 return -1;
 }
 if (fseek(f, 48, SEEK_SET)) {
 ast_log(LOG_WARNING, "Unable to set our position\n");
 return -1;
 }
 if (fwrite(&samples, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write samples\n");
 return -1;
 }
 if (fseek(f, 56, 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 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)
{
 /* Samples per second (always 8000 for this format). */
 unsigned int sample_rate = htoll(8000);
 /* Bytes per second (always 1625 for this format). */
 unsigned int byte_sample_rate = htoll(1625);
 /* This is the size of the "fmt " subchunk */
 unsigned int fmtsize = htoll(20);
 /* WAV #49 */
 unsigned short fmt = htols(49);
 /* Mono = 1 channel */
 unsigned short chans = htols(1);
 /* Each block of data is exactly 65 bytes in size. */
 unsigned int block_align = htoll(MSGSM_FRAME_SIZE);
 /* Not actually 2, but rounded up to the nearest bit */
 unsigned short bits_per_sample = htols(2);
 /* Needed for compressed formats */
 unsigned short extra_format = htols(MSGSM_SAMPLES);
 /* This is the size of the "fact" subchunk */
 unsigned int factsize = htoll(4);
 /* Number of samples in the data chunk */
 unsigned int num_samples = htoll(0);
 /* Number of bytes in the data chunk */
 unsigned int size = htoll(0);
 /* Write a GSM header, ignoring sizes which will be filled in later */

 /* 0: Chunk ID */
 if (fwrite("RIFF", 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 4: Chunk Size */
 if (fwrite(&size, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 8: Chunk Format */
 if (fwrite("WAVE", 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 12: Subchunk 1: ID */
 if (fwrite("fmt ", 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 16: Subchunk 1: Size (minus 8) */
 if (fwrite(&fmtsize, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 20: Subchunk 1: Audio format (49) */
 if (fwrite(&fmt, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 22: Subchunk 1: Number of channels */
 if (fwrite(&chans, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 24: Subchunk 1: Sample rate */
 if (fwrite(&sample_rate, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 28: Subchunk 1: Byte rate */
 if (fwrite(&byte_sample_rate, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 32: Subchunk 1: Block align */
 if (fwrite(&block_align, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 36: Subchunk 1: Bits per sample */
 if (fwrite(&bits_per_sample, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 38: Subchunk 1: Extra format bytes */
 if (fwrite(&extra_format, 1, 2, f) != 2) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 40: Subchunk 2: ID */
 if (fwrite("fact", 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 44: Subchunk 2: Size (minus 8) */
 if (fwrite(&factsize, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 48: Subchunk 2: Number of samples */
 if (fwrite(&num_samples, 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 52: Subchunk 3: ID */
 if (fwrite("data", 1, 4, f) != 4) {
 ast_log(LOG_WARNING, "Unable to write header\n");
 return -1;
 }
 /* 56: Subchunk 3: Size */
 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 wavg_desc *fs = (struct wavg_desc *)s->_private;

 if (check_header(s->f))
 return -1;
 fs->secondhalf = 0; /* not strictly necessary */
 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. */

 if (write_header(s->f))
 return -1;
 return 0;
}

static void wav_close(struct ast_filestream *s)
{
 if (s->mode == O_RDONLY) {
 return;
 }

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

static struct ast_frame *wav_read(struct ast_filestream *s, int *whennext)
{
 /* Send a frame from the file to the appropriate channel */
 struct wavg_desc *fs = (struct wavg_desc *)s->_private;

 s->fr.samples = GSM_SAMPLES;
 AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, GSM_FRAME_SIZE);
 if (fs->secondhalf) {
 /* Just return a frame based on the second GSM frame */
 s->fr.data.ptr = (char *)s->fr.data.ptr + GSM_FRAME_SIZE;
 s->fr.offset += GSM_FRAME_SIZE;
 } else {
 /* read and convert */
 unsigned char msdata[MSGSM_FRAME_SIZE];
 size_t res;

 if ((res = fread(msdata, 1, MSGSM_FRAME_SIZE, s->f)) != MSGSM_FRAME_SIZE) {
 if (res && res != 1) {
 ast_log(LOG_WARNING, "Short read of %s data (expected %d bytes, read %zu): %s\n",
 ast_format_get_name(s->fr.subclass.format), MSGSM_FRAME_SIZE, res,
 strerror(errno));
 }
 return NULL;
 }
 /* Convert from MS format to two real GSM frames */
 conv65(msdata, s->fr.data.ptr);
 }
 fs->secondhalf = !fs->secondhalf;
 *whennext = GSM_SAMPLES;
 return &s->fr;
}

static int wav_write(struct ast_filestream *s, struct ast_frame *f)
{
 int len;
 int size;
 struct wavg_desc *fs = (struct wavg_desc *)s->_private;

 /* XXX this might fail... if the input is a multiple of MSGSM_FRAME_SIZE
 * we assume it is already in the correct format.
 */
 if (!(f->datalen % MSGSM_FRAME_SIZE)) {
 size = MSGSM_FRAME_SIZE;
 fs->secondhalf = 0;
 } else {
 size = GSM_FRAME_SIZE;
 }
 for (len = 0; len < f->datalen ; len += size) {
 int res;
 unsigned char *src, msdata[MSGSM_FRAME_SIZE];
 if (fs->secondhalf) { /* second half of raw gsm to be converted */
 memcpy(s->buf + GSM_FRAME_SIZE, f->data.ptr + len, GSM_FRAME_SIZE);
 conv66((unsigned char *) s->buf, msdata);
 src = msdata;
 fs->secondhalf = 0;
 } else if (size == GSM_FRAME_SIZE) { /* first half of raw gsm */
 memcpy(s->buf, f->data.ptr + len, GSM_FRAME_SIZE);
 src = NULL; /* nothing to write */
 fs->secondhalf = 1;
 } else { /* raw msgsm data */
 src = f->data.ptr + len;
 }
 if (src && (res = fwrite(src, 1, MSGSM_FRAME_SIZE, s->f)) != MSGSM_FRAME_SIZE) {
 ast_log(LOG_WARNING, "Bad write (%d/65): %s\n", res, strerror(errno));
 return -1;
 }
 }
 return 0;
}

static int wav_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
{
 off_t offset = 0, min = MSGSM_DATA_OFFSET, distance, max, cur;
 struct wavg_desc *s = (struct wavg_desc *)fs->_private;

 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;
 }

 /* XXX ideally, should round correctly */
 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;
 }

 /* Compute the distance in bytes, rounded to the block size */
 distance = (sample_offset/MSGSM_SAMPLES) * MSGSM_FRAME_SIZE;
 if (whence == SEEK_SET)
 offset = distance + min;
 else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
 offset = distance + cur;
 else if (whence == SEEK_END)
 offset = max - distance;
 /* always protect against seeking past end of header */
 if (offset < min)
 offset = min;
 if (whence != SEEK_FORCECUR) {
 if (offset > max)
 offset = max;
 } else if (offset > max) {
 int i;
 fseek(fs->f, 0, SEEK_END);
 for (i=0; i< (offset - max) / MSGSM_FRAME_SIZE; i++) {
 if (fwrite(msgsm_silence, 1, MSGSM_FRAME_SIZE, fs->f) != MSGSM_FRAME_SIZE) {
 ast_log(LOG_WARNING, "fwrite() failed: %s\n", strerror(errno));
 }
 }
 }
 s->secondhalf = 0;
 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);
 /* since this will most likely be used later in play or record, lets stick
 * to that level of resolution, just even frames boundaries */
 return (offset - MSGSM_DATA_OFFSET)/MSGSM_FRAME_SIZE*MSGSM_SAMPLES;
}

static struct ast_format_def wav49_f = {
 .name = "wav49",
 .exts = "WAV|wav49",
 .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 = 2*GSM_FRAME_SIZE + AST_FRIENDLY_OFFSET,
 .desc_size = sizeof(struct wavg_desc),
};

static int load_module(void)
{
 wav49_f.format = ast_format_gsm;
 if (ast_format_def_register(&wav49_f))
 return AST_MODULE_LOAD_DECLINE;
 return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
 return ast_format_def_unregister(wav49_f.name);
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Microsoft WAV format (Proprietary GSM)",
 .support_level = AST_MODULE_SUPPORT_CORE,
 .load = load_module,
 .unload = unload_module,
 .load_pri = AST_MODPRI_APP_DEPEND
);