format_wav_gsm.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * 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 guido@sienanet.it */
 
#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
);