format_wav.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 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 guido@sienanet.it */
 
#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_debug(1, "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
);