format_g719.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2010, Anthony Minessale and Digium, Inc.
00005  * Anthony Minessale (anthmct@yahoo.com)
00006  * Kevin P. Fleming <kpfleming@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  *
00021  * \brief ITU G.719 , 64kbps bitrate only
00022  * \arg File name extensions: g719
00023  * \ingroup formats
00024  */
00025 
00026 /*** MODULEINFO
00027    <support_level>core</support_level>
00028  ***/
00029  
00030 #include "asterisk.h"
00031 
00032 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 419592 $")
00033 
00034 #include "asterisk/mod_format.h"
00035 #include "asterisk/module.h"
00036 #include "asterisk/endian.h"
00037 #include "asterisk/format_cache.h"
00038 
00039 #define BUF_SIZE  160      /* 20 milliseconds == 160 bytes, 960 samples */
00040 #define SAMPLES_TO_BYTES(x)   ((typeof(x)) x / ((float) 960 / 160))
00041 #define BYTES_TO_SAMPLES(x)   ((typeof(x)) x * ((float) 960 / 160))
00042 
00043 static struct ast_frame *g719read(struct ast_filestream *s, int *whennext)
00044 {
00045    int res;
00046    /* Send a frame from the file to the appropriate channel */
00047 
00048    AST_FRAME_SET_BUFFER(&s->fr, s->buf, AST_FRIENDLY_OFFSET, BUF_SIZE);
00049    if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) != s->fr.datalen) {
00050       if (res)
00051          ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
00052       return NULL;
00053    }
00054    *whennext = s->fr.samples = BYTES_TO_SAMPLES(res);
00055    return &s->fr;
00056 }
00057 
00058 static int g719write(struct ast_filestream *fs, struct ast_frame *f)
00059 {
00060    int res;
00061 
00062    if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen) {
00063       ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
00064       return -1;
00065    }
00066    return 0;
00067 }
00068 
00069 static int g719seek(struct ast_filestream *fs, off_t sample_offset, int whence)
00070 {
00071    off_t offset = 0, min = 0, cur, max;
00072 
00073    sample_offset = SAMPLES_TO_BYTES(sample_offset);
00074 
00075    if ((cur = ftello(fs->f)) < 0) {
00076       ast_log(AST_LOG_WARNING, "Unable to determine current position in g719 filestream %p: %s\n", fs, strerror(errno));
00077       return -1;
00078    }
00079 
00080    if (fseeko(fs->f, 0, SEEK_END) < 0) {
00081       ast_log(AST_LOG_WARNING, "Unable to seek to end of g719 filestream %p: %s\n", fs, strerror(errno));
00082       return -1;
00083    }
00084 
00085    if ((max = ftello(fs->f)) < 0) {
00086       ast_log(AST_LOG_WARNING, "Unable to determine max position in g719 filestream %p: %s\n", fs, strerror(errno));
00087       return -1;
00088    }
00089 
00090    if (whence == SEEK_SET)
00091       offset = sample_offset;
00092    else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
00093       offset = sample_offset + cur;
00094    else if (whence == SEEK_END)
00095       offset = max - sample_offset;
00096 
00097    if (whence != SEEK_FORCECUR)
00098       offset = (offset > max) ? max : offset;
00099 
00100    /* always protect against seeking past begining. */
00101    offset = (offset < min) ? min : offset;
00102 
00103    return fseeko(fs->f, offset, SEEK_SET);
00104 }
00105 
00106 static int g719trunc(struct ast_filestream *fs)
00107 {
00108    int fd;
00109    off_t cur;
00110 
00111    if ((fd = fileno(fs->f)) < 0) {
00112       ast_log(AST_LOG_WARNING, "Unable to determine file descriptor for g719 filestream %p: %s\n", fs, strerror(errno));
00113       return -1;
00114    }
00115    if ((cur = ftello(fs->f)) < 0) {
00116       ast_log(AST_LOG_WARNING, "Unable to determine current position in g719 filestream %p: %s\n", fs, strerror(errno));
00117       return -1;
00118    }
00119    return ftruncate(fd, cur);
00120 }
00121 
00122 static off_t g719tell(struct ast_filestream *fs)
00123 {
00124    return BYTES_TO_SAMPLES(ftello(fs->f));
00125 }
00126 
00127 static struct ast_format_def g719_f = {
00128    .name = "g719",
00129    .exts = "g719",
00130    .write = g719write,
00131    .seek = g719seek,
00132    .trunc = g719trunc,
00133    .tell = g719tell,
00134    .read = g719read,
00135    .buf_size = BUF_SIZE + AST_FRIENDLY_OFFSET,
00136 };
00137 
00138 static int load_module(void)
00139 {
00140    g719_f.format = ast_format_g719;
00141 
00142    if (ast_format_def_register(&g719_f))
00143       return AST_MODULE_LOAD_DECLINE;
00144    return AST_MODULE_LOAD_SUCCESS;
00145 }
00146 
00147 static int unload_module(void)
00148 {
00149    return ast_format_def_unregister(g719_f.name);
00150 }
00151 
00152 AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "ITU G.719",
00153    .support_level = AST_MODULE_SUPPORT_CORE,
00154    .load = load_module,
00155    .unload = unload_module,
00156    .load_pri = AST_MODPRI_APP_DEPEND
00157 );
00158 

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