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
 */
 
#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "$Revision: 315258 $")

#include "asterisk/mod_format.h"
#include "asterisk/module.h"
#include "asterisk/endian.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

struct wav_desc { /* format-specific parameters */
   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)
{
   short format, chans, bysam, bisam;
   int bysec;
   int freq;
   if (hsize < 16) {
      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) != 1) {
      ast_log(LOG_WARNING, "Not a wav 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(&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,ltohl(hsize)-16,SEEK_CUR) == -1 ) {
      ast_log(LOG_WARNING, "Failed to skip remaining header bytes: %d\n", ltohl(hsize)-16 );
      return -1;
   }
   return 0;
}

static int check_header(FILE *f)
{
   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;
   }
   size = ltohl(size);
   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;
       }
       data = ltohl(data);
      if (memcmp(&buf, "fmt ", 4) == 0) {
         if (check_header_fmt(f, data))
            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)
{
   unsigned int hz=htoll(8000);
   unsigned int bhz = htoll(16000);
   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);
   /* 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 = (struct wav_desc *)s->_private;
   if ((tmp->maxlen = check_header(s->f)) < 0)
      return -1;
   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)
{
   char zero = 0;
   struct wav_desc *fs = (struct wav_desc *)s->_private;

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

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

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

   here = ftello(s->f);
   if (fs->maxlen - here < bytes)      /* truncate if necessary */
      bytes = fs->maxlen - here;
   if (bytes < 0)
      bytes = 0;
/*    ast_debug(1, "here: %d, maxlen: %d, bytes: %d\n", here, s->maxlen, bytes); */
   s->fr.frametype = AST_FRAME_VOICE;
   s->fr.subclass = AST_FORMAT_SLINEAR;
   s->fr.mallocd = 0;
   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 (%d) (%s)!\n", res, strerror(errno));
      return NULL;
   }
   s->fr.datalen = res;
   s->fr.samples = samples = res / 2;

   tmp = (short *)(s->fr.data.ptr);
#if __BYTE_ORDER == __BIG_ENDIAN
   /* 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[8000], *tmpi;
#endif
   struct wav_desc *s = (struct wav_desc *)fs->_private;
   int res;

   if (f->frametype != AST_FRAME_VOICE) {
      ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
      return -1;
   }
   if (f->subclass != AST_FORMAT_SLINEAR) {
      ast_log(LOG_WARNING, "Asked to write non-SLINEAR frame (%d)!\n", f->subclass);
      return -1;
   }
   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, max, cur, offset = 0, samples;

   samples = sample_offset * 2; /* SLINEAR is 16 bits mono, so sample_offset * 2 = bytes */
   min = 44; /* wav header is 44 bytes */
   cur = ftello(fs->f);
   fseeko(fs->f, 0, SEEK_END);
   max = ftello(fs->f);
   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)
{
   if (ftruncate(fileno(fs->f), ftello(fs->f)))
      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 const struct ast_format wav_f = {
   .name = "wav",
   .exts = "wav",
   .format = AST_FORMAT_SLINEAR,
   .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 load_module(void)
{
   if (ast_format_register(&wav_f))
      return AST_MODULE_LOAD_FAILURE;
   return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
   return ast_format_unregister(wav_f.name);
}  

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "Microsoft WAV format (8000Hz Signed Linear)",
   .load = load_module,
   .unload = unload_module,
   .load_pri = 10,
);