formats/format_sln16.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 1999 - 2008, Anthony Minessale and Digium, Inc.
   5  * Anthony Minessale (anthmct@yahoo.com)
   6  * Kevin P. Fleming <kpfleming@digium.com>
   7  *
   8  * See http://www.asterisk.org for more information about
   9  * the Asterisk project. Please do not directly contact
  10  * any of the maintainers of this project for assistance;
  11  * the project provides a web site, mailing lists and IRC
  12  * channels for your use.
  13  *
  14  * This program is free software, distributed under the terms of
  15  * the GNU General Public License Version 2. See the LICENSE file
  16  * at the top of the source tree.
  17  */
  18
  19 /*! \file
  20  *
  21  * \brief RAW SLINEAR 16 Format
  22  * \arg File name extensions: sln16
  23  * \ingroup formats
  24  */
  25
  26 #include "asterisk.h"
  27
  28 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  29
  30 #include "asterisk/mod_format.h"
  31 #include "asterisk/module.h"
  32 #include "asterisk/endian.h"
  33
  34 #define BUF_SIZE        640             /* 640 bytes, 320 samples */
  35 #define SLIN_SAMPLES    320
  36
  37 static struct ast_frame *slinear_read(struct ast_filestream *s, int *whennext)
  38 {
  39         int res;
  40         /* Send a frame from the file to the appropriate channel */
  41
  42         s->fr.frametype = AST_FRAME_VOICE;
  43         s->fr.subclass = AST_FORMAT_SLINEAR16;
  44         s->fr.mallocd = 0;
  45         AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, BUF_SIZE);
  46         if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) < 1) {
  47                 if (res)
  48                         ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
  49                 return NULL;
  50         }
  51         *whennext = s->fr.samples = res/2;
  52         s->fr.datalen = res;
  53         return &s->fr;
  54 }
  55
  56 static int slinear_write(struct ast_filestream *fs, struct ast_frame *f)
  57 {
  58         int res;
  59
  60         if (f->frametype != AST_FRAME_VOICE) {
  61                 ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
  62                 return -1;
  63         }
  64         if (f->subclass != AST_FORMAT_SLINEAR16) {
  65                 ast_log(LOG_WARNING, "Asked to write non-slinear16 frame (%d)!\n", f->subclass);
  66                 return -1;
  67         }
  68         if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen) {
  69                 ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
  70                 return -1;
  71         }
  72         return 0;
  73 }
  74
  75 static int slinear_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
  76 {
  77         off_t offset = 0, min = 0, cur, max;
  78
  79         sample_offset <<= 1;
  80
  81         cur = ftello(fs->f);
  82
  83         fseeko(fs->f, 0, SEEK_END);
  84
  85         max = ftello(fs->f);
  86
  87         if (whence == SEEK_SET)
  88                 offset = sample_offset;
  89         else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
  90                 offset = sample_offset + cur;
  91         else if (whence == SEEK_END)
  92                 offset = max - sample_offset;
  93
  94         if (whence != SEEK_FORCECUR)
  95                 offset = (offset > max) ? max : offset;
  96
  97         /* always protect against seeking past begining. */
  98         offset = (offset < min) ? min : offset;
  99
 100         return fseeko(fs->f, offset, SEEK_SET);
 101 }
 102
 103 static int slinear_trunc(struct ast_filestream *fs)
 104 {
 105         return ftruncate(fileno(fs->f), ftello(fs->f));
 106 }
 107
 108 static off_t slinear_tell(struct ast_filestream *fs)
 109 {
 110         return ftello(fs->f) / 2;
 111 }
 112
 113 static const struct ast_format slin_f = {
 114         .name = "sln16",
 115         .exts = "sln16",
 116         .format = AST_FORMAT_SLINEAR16,
 117         .write = slinear_write,
 118         .seek = slinear_seek,
 119         .trunc = slinear_trunc,
 120         .tell = slinear_tell,
 121         .read = slinear_read,
 122         .buf_size = BUF_SIZE + AST_FRIENDLY_OFFSET,
 123 };
 124
 125 static int load_module(void)
 126 {
 127         if (ast_format_register(&slin_f))
 128                 return AST_MODULE_LOAD_FAILURE;
 129
 130         return AST_MODULE_LOAD_SUCCESS;
 131 }
 132
 133 static int unload_module(void)
 134 {
 135         return ast_format_unregister(slin_f.name);
 136 }
 137
 138 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Raw Signed Linear 16KHz Audio support (SLN16)");