src/sox-fmt.c

   1 /* libSoX file format: SoX native   (c) 2008 robs@users.sourceforge.net
   2  *
   3  * This library is free software; you can redistribute it and/or modify it
   4  * under the terms of the GNU Lesser General Public License as published by
   5  * the Free Software Foundation; either version 2.1 of the License, or (at
   6  * your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public License
  14  * along with this library; if not, write to the Free Software Foundation,
  15  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  16  */
  17
  18 #include "sox_i.h"
  19 #include <string.h>
  20
  21 static char const magic[2][4] = {".SoX", "XoS."};
  22 #define FIXED_HDR     (4 + 8 + 8 + 4 + 4) /* Without magic */
  23
  24 static int startread(sox_format_t * ft)
  25 {
  26   char     magic_[sizeof(magic[0])];
  27   uint32_t headers_bytes, num_channels, comments_bytes;
  28   uint64_t num_samples;
  29   double   rate;
  30
  31   if (lsx_readdw(ft, (uint32_t *)&magic_))
  32     return SOX_EOF;
  33
  34   if (memcmp(magic[MACHINE_IS_BIGENDIAN], magic_, sizeof(magic_))) {
  35     if (memcmp(magic[MACHINE_IS_LITTLEENDIAN], magic_, sizeof(magic_))) {
  36       lsx_fail_errno(ft, SOX_EHDR, "can't find sox file format identifier");
  37       return SOX_EOF;
  38     }
  39     ft->encoding.reverse_bytes = !ft->encoding.reverse_bytes;
  40     lsx_report("file is opposite endian");
  41   }
  42   if (lsx_readdw(ft, &headers_bytes) ||
  43       lsx_readqw(ft, &num_samples) ||
  44       lsx_readdf(ft, &rate) ||
  45       lsx_readdw(ft, &num_channels) ||
  46       lsx_readdw(ft, &comments_bytes))
  47     return SOX_EOF;
  48
  49   if (((headers_bytes + 4) & 7) || headers_bytes < FIXED_HDR + comments_bytes ||
  50       (num_channels > 65535)) /* Reserve top 16 bits */ {
  51     lsx_fail_errno(ft, SOX_EHDR, "invalid sox file format header");
  52     return SOX_EOF;
  53   }
  54
  55   if (comments_bytes) {
  56     char * buf = lsx_calloc(1, (size_t)comments_bytes + 1); /* ensure nul-terminated */
  57     if (lsx_readchars(ft, buf, (size_t)comments_bytes) != SOX_SUCCESS) {
  58       free(buf);
  59       return SOX_EOF;
  60     }
  61     sox_append_comments(&ft->oob.comments, buf);
  62     free(buf);
  63   }
  64
  65   /* Consume any bytes after the comments and before the start of the audio
  66    * block.  These may include comment padding up to a multiple of 8 bytes,
  67    * and further header information that might be defined in future. */
  68   lsx_seeki(ft, (off_t)(headers_bytes - FIXED_HDR - comments_bytes), SEEK_CUR);
  69
  70   return lsx_check_read_params(
  71       ft, num_channels, rate, SOX_ENCODING_SIGN2, 32, num_samples, sox_true);
  72 }
  73
  74 static int write_header(sox_format_t * ft)
  75 {
  76   char * comments  = lsx_cat_comments(ft->oob.comments);
  77   size_t comments_len = strlen(comments);
  78   size_t comments_bytes = (comments_len + 7) & ~7u; /* Multiple of 8 bytes */
  79   uint64_t size   = ft->olength? ft->olength : ft->signal.length;
  80   int error;
  81   uint32_t header;
  82   memcpy(&header, magic[MACHINE_IS_BIGENDIAN], sizeof(header));
  83   error = 0
  84   ||lsx_writedw(ft, header)
  85   ||lsx_writedw(ft, FIXED_HDR + (unsigned)comments_bytes)
  86   ||lsx_writeqw(ft, size)
  87   ||lsx_writedf(ft, ft->signal.rate)
  88   ||lsx_writedw(ft, ft->signal.channels)
  89   ||lsx_writedw(ft, (unsigned)comments_len)
  90   ||lsx_writechars(ft, comments, comments_len)
  91   ||lsx_padbytes(ft, comments_bytes - comments_len);
  92   free(comments);
  93   return error? SOX_EOF: SOX_SUCCESS;
  94 }
  95
  96 LSX_FORMAT_HANDLER(sox)
  97 {
  98   static char const * const names[] = {"sox", NULL};
  99   static unsigned const write_encodings[] = {SOX_ENCODING_SIGN2, 32, 0, 0};
 100   static sox_format_handler_t const handler = {SOX_LIB_VERSION_CODE,
 101     "SoX native intermediate format", names, SOX_FILE_REWIND,
 102     startread, lsx_rawread, NULL, write_header, lsx_rawwrite, NULL,
 103     lsx_rawseek, write_encodings, NULL, 0
 104   };
 105   return &handler;
 106 }