Asterisk.org: Developer Documentation (28 Oct 2009)

Wed Oct 28 15:47:53 2009

## Asterisk developer's documentation

# format_au.c

Go to the documentation of this file.

    00001 /*
    00002  * Asterisk -- An open source telephony toolkit.
    00003  *
    00004  * Copyright (C) 2005, Andriy Pylypenko
    00005  * Code based on format_wav.c by Mark Spencer
    00006  *
    00007  * See http://www.asterisk.org for more information about
    00008  * the Asterisk project. Please do not directly contact
    00009  * any of the maintainers of this project for assistance;
    00010  * the project provides a web site, mailing lists and IRC
    00011  * channels for your use.
    00012  *
    00013  * This program is free software, distributed under the terms of
    00014  * the GNU General Public License Version 2. See the LICENSE file
    00015  * at the top of the source tree.
    00016  */
    00017
    00018 /*!
    00019  * \file
    00020  *
    00021  * \brief Work with Sun Microsystems AU format.
    00022  *
    00023  * signed linear
    00024  * \arg File extension: au
    00025  * \ingroup formats
    00026  */
    00027
    00028 #include <stdlib.h>
    00029 #include <sys/time.h>
    00030 #include <stdio.h>
    00031 #include <unistd.h>
    00032 #include <errno.h>
    00033 #include <string.h>
    00034
    00035 #include "asterisk.h"
    00036
    00037 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 7221 $")
    00038
    00039 #include "asterisk/lock.h"
    00040 #include "asterisk/channel.h"
    00041 #include "asterisk/file.h"
    00042 #include "asterisk/logger.h"
    00043 #include "asterisk/sched.h"
    00044 #include "asterisk/module.h"
    00045 #include "asterisk/endian.h"
    00046
    00047 #define BUF_SIZE     160
    00048
    00049 #define AU_HEADER_SIZE     24
    00050 #define AU_HEADER(var)     u_int32_t var[6]
    00051
    00052 #define AU_HDR_MAGIC_OFF   0
    00053 #define AU_HDR_HDR_SIZE_OFF   1
    00054 #define AU_HDR_DATA_SIZE_OFF  2
    00055 #define AU_HDR_ENCODING_OFF   3
    00056 #define AU_HDR_SAMPLE_RATE_OFF   4
    00057 #define AU_HDR_CHANNELS_OFF   5
    00058
    00059 #define AU_ENC_8BIT_ULAW   1
    00060
    00061 struct ast_filestream {
    00062    void *reserved[AST_RESERVED_POINTERS];
    00063    /* This is what a filestream means to us */
    00064    FILE *f;             /* Descriptor */
    00065    struct ast_channel *owner;
    00066    struct ast_frame fr;       /* Frame information */
    00067    char waste[AST_FRIENDLY_OFFSET]; /* Buffer for sending frames, etc */
    00068    char empty;          /* Empty character */
    00069    short buf[BUF_SIZE];
    00070 };
    00071
    00072
    00073 AST_MUTEX_DEFINE_STATIC(au_lock);
    00074 static int localusecnt = 0;
    00075
    00076 static char *name = "au";
    00077 static char *desc = "Sun Microsystems AU format (signed linear)";
    00078 static char *exts = "au";
    00079
    00080
    00081 #define AU_MAGIC 0x2e736e64
    00082 #if __BYTE_ORDER == __BIG_ENDIAN
    00083 #define htoll(b) (b)
    00084 #define htols(b) (b)
    00085 #define ltohl(b) (b)
    00086 #define ltohs(b) (b)
    00087 #else
    00088 #if __BYTE_ORDER == __LITTLE_ENDIAN
    00089 #define htoll(b)  \
    00090           (((((b)      ) & 0xFF) << 24) | \
    00091           ((((b) >>  8) & 0xFF) << 16) | \
    00092          ((((b) >> 16) & 0xFF) <<  8) | \
    00093          ((((b) >> 24) & 0xFF)      ))
    00094 #define htols(b) \
    00095           (((((b)      ) & 0xFF) << 8) | \
    00096          ((((b) >> 8) & 0xFF)      ))
    00097 #define ltohl(b) htoll(b)
    00098 #define ltohs(b) htols(b)
    00099 #else
    00100 #error "Endianess not defined"
    00101 #endif
    00102 #endif
    00103
    00104
    00105 static int check_header(FILE *f)
    00106 {
    00107    AU_HEADER(header);
    00108    u_int32_t magic;
    00109    u_int32_t hdr_size;
    00110    u_int32_t data_size;
    00111    u_int32_t encoding;
    00112    u_int32_t sample_rate;
    00113    u_int32_t channels;
    00114
    00115    if (fread(header, 1, AU_HEADER_SIZE, f) != AU_HEADER_SIZE) {
    00116       ast_log(LOG_WARNING, "Read failed (header)\n");
    00117       return -1;
    00118    }
    00119    magic = ltohl(header[AU_HDR_MAGIC_OFF]);
    00120    if (magic != (u_int32_t) AU_MAGIC) {
    00121       ast_log(LOG_WARNING, "Bad magic: 0x%x\n", magic);
    00122    }
    00123 /* hdr_size = ltohl(header[AU_HDR_HDR_SIZE_OFF]);
    00124    if (hdr_size < AU_HEADER_SIZE)*/
    00125    hdr_size = AU_HEADER_SIZE;
    00126 /* data_size = ltohl(header[AU_HDR_DATA_SIZE_OFF]); */
    00127    encoding = ltohl(header[AU_HDR_ENCODING_OFF]);
    00128    if (encoding != AU_ENC_8BIT_ULAW) {
    00129       ast_log(LOG_WARNING, "Unexpected format: %d. Only 8bit ULAW allowed (%d)\n", encoding, AU_ENC_8BIT_ULAW);
    00130       return -1;
    00131    }
    00132    sample_rate = ltohl(header[AU_HDR_SAMPLE_RATE_OFF]);
    00133    if (sample_rate != 8000) {
    00134       ast_log(LOG_WARNING, "Sample rate can only be 8000 not %d\n", sample_rate);
    00135       return -1;
    00136    }
    00137    channels = ltohl(header[AU_HDR_CHANNELS_OFF]);
    00138    if (channels != 1) {
    00139       ast_log(LOG_WARNING, "Not in mono: channels=%d\n", channels);
    00140       return -1;
    00141    }
    00142    /* Skip to data */
    00143    fseek(f, 0, SEEK_END);
    00144    data_size = ftell(f) - hdr_size;
    00145    if (fseek(f, hdr_size, SEEK_SET) == -1 ) {
    00146       ast_log(LOG_WARNING, "Failed to skip to data: %d\n", hdr_size);
    00147       return -1;
    00148    }
    00149    return data_size;
    00150 }
    00151
    00152 static int update_header(FILE *f)
    00153 {
    00154    off_t cur, end;
    00155    u_int32_t datalen;
    00156    int bytes;
    00157
    00158    cur = ftell(f);
    00159    fseek(f, 0, SEEK_END);
    00160    end = ftell(f);
    00161    /* data starts 24 bytes in */
    00162    bytes = end - AU_HEADER_SIZE;
    00163    datalen = htoll(bytes);
    00164
    00165    if (cur < 0) {
    00166       ast_log(LOG_WARNING, "Unable to find our position\n");
    00167       return -1;
    00168    }
    00169    if (fseek(f, AU_HDR_DATA_SIZE_OFF * sizeof(u_int32_t), SEEK_SET)) {
    00170       ast_log(LOG_WARNING, "Unable to set our position\n");
    00171       return -1;
    00172    }
    00173    if (fwrite(&datalen, 1, sizeof(datalen), f) != sizeof(datalen)) {
    00174       ast_log(LOG_WARNING, "Unable to set write file size\n");
    00175       return -1;
    00176    }
    00177    if (fseek(f, cur, SEEK_SET)) {
    00178       ast_log(LOG_WARNING, "Unable to return to position\n");
    00179       return -1;
    00180    }
    00181    return 0;
    00182 }
    00183
    00184 static int write_header(FILE *f)
    00185 {
    00186    AU_HEADER(header);
    00187
    00188    header[AU_HDR_MAGIC_OFF] = htoll((u_int32_t) AU_MAGIC);
    00189    header[AU_HDR_HDR_SIZE_OFF] = htoll(AU_HEADER_SIZE);
    00190    header[AU_HDR_DATA_SIZE_OFF] = 0;
    00191    header[AU_HDR_ENCODING_OFF] = htoll(AU_ENC_8BIT_ULAW);
    00192    header[AU_HDR_SAMPLE_RATE_OFF] = htoll(8000);
    00193    header[AU_HDR_CHANNELS_OFF] = htoll(1);
    00194
    00195    /* Write an au header, ignoring sizes which will be filled in later */
    00196    fseek(f, 0, SEEK_SET);
    00197    if (fwrite(header, 1, AU_HEADER_SIZE, f) != AU_HEADER_SIZE) {
    00198       ast_log(LOG_WARNING, "Unable to write header\n");
    00199       return -1;
    00200    }
    00201    return 0;
    00202 }
    00203
    00204 static struct ast_filestream *au_open(FILE *f)
    00205 {
    00206    struct ast_filestream *tmp;
    00207
    00208    if (!(tmp = malloc(sizeof(struct ast_filestream)))) {
    00209       ast_log(LOG_ERROR, "Out of memory\n");
    00210       return NULL;
    00211    }
    00212
    00213    memset(tmp, 0, sizeof(struct ast_filestream));
    00214    if (check_header(f) < 0) {
    00215       free(tmp);
    00216       return NULL;
    00217    }
    00218    if (ast_mutex_lock(&au_lock)) {
    00219       ast_log(LOG_WARNING, "Unable to lock au count\n");
    00220       free(tmp);
    00221       return NULL;
    00222    }
    00223    tmp->f = f;
    00224    tmp->fr.data = tmp->buf;
    00225    tmp->fr.frametype = AST_FRAME_VOICE;
    00226    tmp->fr.subclass = AST_FORMAT_ULAW;
    00227    /* datalen will vary for each frame */
    00228    tmp->fr.src = name;
    00229    tmp->fr.mallocd = 0;
    00230    localusecnt++;
    00231    ast_mutex_unlock(&au_lock);
    00232    ast_update_use_count();
    00233    return tmp;
    00234 }
    00235
    00236 static struct ast_filestream *au_rewrite(FILE *f, const char *comment)
    00237 {
    00238    struct ast_filestream *tmp;
    00239
    00240    if ((tmp = malloc(sizeof(struct ast_filestream))) == NULL) {
    00241       ast_log(LOG_ERROR, "Out of memory\n");
    00242       return NULL;
    00243    }
    00244
    00245    memset(tmp, 0, sizeof(struct ast_filestream));
    00246    if (write_header(f)) {
    00247       free(tmp);
    00248       return NULL;
    00249    }
    00250    if (ast_mutex_lock(&au_lock)) {
    00251       ast_log(LOG_WARNING, "Unable to lock au count\n");
    00252       free(tmp);
    00253       return NULL;
    00254    }
    00255    tmp->f = f;
    00256    localusecnt++;
    00257    ast_mutex_unlock(&au_lock);
    00258    ast_update_use_count();
    00259    return tmp;
    00260 }
    00261
    00262 static void au_close(struct ast_filestream *s)
    00263 {
    00264    if (ast_mutex_lock(&au_lock)) {
    00265       ast_log(LOG_WARNING, "Unable to lock au count\n");
    00266       return;
    00267    }
    00268    localusecnt--;
    00269    ast_mutex_unlock(&au_lock);
    00270    ast_update_use_count();
    00271    fclose(s->f);
    00272    free(s);
    00273 }
    00274
    00275 static struct ast_frame *au_read(struct ast_filestream *s, int *whennext)
    00276 {
    00277    int res;
    00278    int delay;
    00279    /* Send a frame from the file to the appropriate channel */
    00280
    00281    s->fr.frametype = AST_FRAME_VOICE;
    00282    s->fr.subclass = AST_FORMAT_ULAW;
    00283    s->fr.offset = AST_FRIENDLY_OFFSET;
    00284    s->fr.mallocd = 0;
    00285    s->fr.data = s->buf;
    00286    if ((res = fread(s->buf, 1, BUF_SIZE, s->f)) < 1) {
    00287       if (res)
    00288          ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
    00289       return NULL;
    00290    }
    00291    s->fr.samples = res;
    00292    s->fr.datalen = res;
    00293    delay = s->fr.samples;
    00294    *whennext = delay;
    00295    return &s->fr;
    00296 }
    00297
    00298 static int au_write(struct ast_filestream *fs, struct ast_frame *f)
    00299 {
    00300    int res;
    00301
    00302    if (f->frametype != AST_FRAME_VOICE) {
    00303       ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
    00304       return -1;
    00305    }
    00306    if (f->subclass != AST_FORMAT_ULAW) {
    00307       ast_log(LOG_WARNING, "Asked to write non-ulaw frame (%d)!\n", f->subclass);
    00308       return -1;
    00309    }
    00310    if ((res = fwrite(f->data, 1, f->datalen, fs->f)) != f->datalen) {
    00311          ast_log(LOG_WARNING, "Bad write (%d/%d): %s\n", res, f->datalen, strerror(errno));
    00312          return -1;
    00313    }
    00314    update_header(fs->f);
    00315    return 0;
    00316 }
    00317
    00318 static int au_seek(struct ast_filestream *fs, long sample_offset, int whence)
    00319 {
    00320    off_t min, max, cur;
    00321    long offset = 0, samples;
    00322
    00323    samples = sample_offset;
    00324    min = AU_HEADER_SIZE;
    00325    cur = ftell(fs->f);
    00326    fseek(fs->f, 0, SEEK_END);
    00327    max = ftell(fs->f);
    00328    if (whence == SEEK_SET)
    00329       offset = samples + min;
    00330    else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
    00331       offset = samples + cur;
    00332    else if (whence == SEEK_END)
    00333       offset = max - samples;
    00334         if (whence != SEEK_FORCECUR) {
    00335       offset = (offset > max) ? max : offset;
    00336    }
    00337    /* always protect the header space. */
    00338    offset = (offset < min) ? min : offset;
    00339    return fseek(fs->f, offset, SEEK_SET);
    00340 }
    00341
    00342 static int au_trunc(struct ast_filestream *fs)
    00343 {
    00344    if (ftruncate(fileno(fs->f), ftell(fs->f)))
    00345       return -1;
    00346    return update_header(fs->f);
    00347 }
    00348
    00349 static long au_tell(struct ast_filestream *fs)
    00350 {
    00351    off_t offset;
    00352
    00353    offset = ftell(fs->f);
    00354    return offset - AU_HEADER_SIZE;
    00355 }
    00356
    00357 static char *au_getcomment(struct ast_filestream *s)
    00358 {
    00359    return NULL;
    00360 }
    00361
    00362 int load_module()
    00363 {
    00364    return ast_format_register(name, exts, AST_FORMAT_ULAW,
    00365                au_open,
    00366                au_rewrite,
    00367                au_write,
    00368                au_seek,
    00369                au_trunc,
    00370                au_tell,
    00371                au_read,
    00372                au_close,
    00373                au_getcomment);
    00374 }
    00375
    00376 int unload_module()
    00377 {
    00378    return ast_format_unregister(name);
    00379 }
    00380
    00381 int usecount()
    00382 {
    00383    return localusecnt;
    00384 }
    00385
    00386 char *description()
    00387 {
    00388    return desc;
    00389 }
    00390
    00391 char *key()
    00392 {
    00393    return ASTERISK_GPL_KEY;
    00394 }