Wed Aug 15 01:24:24 2007

Asterisk developer's documentation


translate.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2006, Digium, Inc.
00005  *
00006  * Mark Spencer <markster@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 Translate via the use of pseudo channels
00022  *
00023  * \author Mark Spencer <markster@digium.com> 
00024  */
00025 
00026 #include "asterisk.h"
00027 
00028 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 67631 $")
00029 
00030 #include <sys/types.h>
00031 #include <sys/socket.h>
00032 #include <sys/time.h>
00033 #include <unistd.h>
00034 #include <stdlib.h>
00035 #include <string.h>
00036 #include <stdio.h>
00037 
00038 #include "asterisk/lock.h"
00039 #include "asterisk/channel.h"
00040 #include "asterisk/logger.h"
00041 #include "asterisk/translate.h"
00042 #include "asterisk/module.h"
00043 #include "asterisk/options.h"
00044 #include "asterisk/frame.h"
00045 #include "asterisk/sched.h"
00046 #include "asterisk/cli.h"
00047 #include "asterisk/term.h"
00048 
00049 #define MAX_RECALC 200 /* max sample recalc */
00050 
00051 /*! \brief the list of translators */
00052 static AST_LIST_HEAD_STATIC(translators, ast_translator);
00053 
00054 struct translator_path {
00055    struct ast_translator *step;  /*!< Next step translator */
00056    unsigned int cost;      /*!< Complete cost to destination */
00057    unsigned int multistep;    /*!< Multiple conversions required for this translation */
00058 };
00059 
00060 /*! \brief a matrix that, for any pair of supported formats,
00061  * indicates the total cost of translation and the first step.
00062  * The full path can be reconstricted iterating on the matrix
00063  * until step->dstfmt == desired_format.
00064  *
00065  * Array indexes are 'src' and 'dest', in that order.
00066  *
00067  * Note: the lock in the 'translators' list is also used to protect
00068  * this structure.
00069  */
00070 static struct translator_path tr_matrix[MAX_FORMAT][MAX_FORMAT];
00071 
00072 /*! \todo
00073  * TODO: sample frames for each supported input format.
00074  * We build this on the fly, by taking an SLIN frame and using
00075  * the existing converter to play with it.
00076  */
00077 
00078 /*! \brief returns the index of the lowest bit set */
00079 static force_inline int powerof(unsigned int d)
00080 {
00081    int x = ffs(d);
00082 
00083    if (x)
00084       return x - 1;
00085 
00086    ast_log(LOG_WARNING, "No bits set? %d\n", d);
00087 
00088    return -1;
00089 }
00090 
00091 /*
00092  * wrappers around the translator routines.
00093  */
00094 
00095 /*!
00096  * \brief Allocate the descriptor, required outbuf space,
00097  * and possibly also plc and desc.
00098  */
00099 static void *newpvt(struct ast_translator *t)
00100 {
00101    struct ast_trans_pvt *pvt;
00102    int len;
00103    int useplc = t->plc_samples > 0 && t->useplc;   /* cache, because it can change on the fly */
00104    char *ofs;
00105 
00106    /*
00107     * compute the required size adding private descriptor,
00108     * plc, buffer, AST_FRIENDLY_OFFSET.
00109     */
00110    len = sizeof(*pvt) + t->desc_size;
00111    if (useplc)
00112       len += sizeof(plc_state_t);
00113    if (t->buf_size)
00114       len += AST_FRIENDLY_OFFSET + t->buf_size;
00115    pvt = ast_calloc(1, len);
00116    if (!pvt)
00117       return NULL;
00118    pvt->t = t;
00119    ofs = (char *)(pvt + 1);   /* pointer to data space */
00120    if (t->desc_size) {     /* first comes the descriptor */
00121       pvt->pvt = ofs;
00122       ofs += t->desc_size;
00123    }
00124    if (useplc) {        /* then plc state */
00125       pvt->plc = (plc_state_t *)ofs;
00126       ofs += sizeof(plc_state_t);
00127    }
00128    if (t->buf_size)     /* finally buffer and header */
00129       pvt->outbuf = ofs + AST_FRIENDLY_OFFSET;
00130    /* call local init routine, if present */
00131    if (t->newpvt && t->newpvt(pvt)) {
00132       free(pvt);
00133       return NULL;
00134    }
00135    ast_module_ref(t->module);
00136    return pvt;
00137 }
00138 
00139 static void destroy(struct ast_trans_pvt *pvt)
00140 {
00141    struct ast_translator *t = pvt->t;
00142 
00143    if (t->destroy)
00144       t->destroy(pvt);
00145    free(pvt);
00146    ast_module_unref(t->module);
00147 }
00148 
00149 /*! \brief framein wrapper, deals with plc and bound checks.  */
00150 static int framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
00151 {
00152    int16_t *dst = (int16_t *)pvt->outbuf;
00153    int ret;
00154    int samples = pvt->samples;   /* initial value */
00155    
00156    /* Copy the last in jb timing info to the pvt */
00157    pvt->f.has_timing_info = f->has_timing_info;
00158    pvt->f.ts = f->ts;
00159    pvt->f.len = f->len;
00160    pvt->f.seqno = f->seqno;
00161 
00162    if (f->samples == 0) {
00163       ast_log(LOG_WARNING, "no samples for %s\n", pvt->t->name);
00164    }
00165    if (pvt->t->buffer_samples) { /* do not pass empty frames to callback */
00166       if (f->datalen == 0) { /* perform PLC with nominal framesize of 20ms/160 samples */
00167          if (pvt->plc) {
00168             int l = pvt->t->plc_samples;
00169             if (pvt->samples + l > pvt->t->buffer_samples) {
00170                ast_log(LOG_WARNING, "Out of buffer space\n");
00171                return -1;
00172             }
00173             l = plc_fillin(pvt->plc, dst + pvt->samples, l);
00174             pvt->samples += l;
00175             pvt->datalen = pvt->samples * 2; /* SLIN has 2bytes for 1sample */
00176          }
00177          /* We don't want generic PLC. If the codec has native PLC, then do that */
00178          if (!pvt->t->native_plc)
00179             return 0;
00180       }
00181       if (pvt->samples + f->samples > pvt->t->buffer_samples) {
00182          ast_log(LOG_WARNING, "Out of buffer space\n");
00183          return -1;
00184       }
00185    }
00186    /* we require a framein routine, wouldn't know how to do
00187     * it otherwise.
00188     */
00189    ret = pvt->t->framein(pvt, f);
00190    /* possibly store data for plc */
00191    if (!ret && pvt->plc) {
00192       int l = pvt->t->plc_samples;
00193       if (pvt->samples < l)
00194          l = pvt->samples;
00195       plc_rx(pvt->plc, dst + pvt->samples - l, l);
00196    }
00197    /* diagnostic ... */
00198    if (pvt->samples == samples)
00199       ast_log(LOG_WARNING, "%s did not update samples %d\n",
00200          pvt->t->name, pvt->samples);
00201         return ret;
00202 }
00203 
00204 /*! \brief generic frameout routine.
00205  * If samples and datalen are 0, take whatever is in pvt
00206  * and reset them, otherwise take the values in the caller and
00207  * leave alone the pvt values.
00208  */
00209 struct ast_frame *ast_trans_frameout(struct ast_trans_pvt *pvt,
00210    int datalen, int samples)
00211 {
00212    struct ast_frame *f = &pvt->f;
00213 
00214         if (samples)
00215       f->samples = samples;
00216    else {
00217       if (pvt->samples == 0)
00218          return NULL;
00219       f->samples = pvt->samples;
00220       pvt->samples = 0;
00221    }
00222    if (datalen)
00223       f->datalen = datalen;
00224    else {
00225       f->datalen = pvt->datalen;
00226       pvt->datalen = 0;
00227    }
00228 
00229    f->frametype = AST_FRAME_VOICE;
00230    f->subclass = 1 << (pvt->t->dstfmt);
00231    f->mallocd = 0;
00232    f->offset = AST_FRIENDLY_OFFSET;
00233    f->src = pvt->t->name;
00234    f->data = pvt->outbuf;
00235    return f;
00236 }
00237 
00238 static struct ast_frame *default_frameout(struct ast_trans_pvt *pvt)
00239 {
00240    return ast_trans_frameout(pvt, 0, 0);
00241 }
00242 
00243 /* end of callback wrappers and helpers */
00244 
00245 void ast_translator_free_path(struct ast_trans_pvt *p)
00246 {
00247    struct ast_trans_pvt *pn = p;
00248    while ( (p = pn) ) {
00249       pn = p->next;
00250       destroy(p);
00251    }
00252 }
00253 
00254 /*! \brief Build a chain of translators based upon the given source and dest formats */
00255 struct ast_trans_pvt *ast_translator_build_path(int dest, int source)
00256 {
00257    struct ast_trans_pvt *head = NULL, *tail = NULL;
00258    
00259    source = powerof(source);
00260    dest = powerof(dest);
00261    
00262    AST_LIST_LOCK(&translators);
00263 
00264    while (source != dest) {
00265       struct ast_trans_pvt *cur;
00266       struct ast_translator *t = tr_matrix[source][dest].step;
00267       if (!t) {
00268          ast_log(LOG_WARNING, "No translator path from %s to %s\n", 
00269             ast_getformatname(source), ast_getformatname(dest));
00270          AST_LIST_UNLOCK(&translators);
00271          return NULL;
00272       }
00273       if (!(cur = newpvt(t))) {
00274          ast_log(LOG_WARNING, "Failed to build translator step from %d to %d\n", source, dest);
00275          if (head)
00276             ast_translator_free_path(head);  
00277          AST_LIST_UNLOCK(&translators);
00278          return NULL;
00279       }
00280       if (!head)
00281          head = cur;
00282       else
00283          tail->next = cur;
00284       tail = cur;
00285       cur->nextin = cur->nextout = ast_tv(0, 0);
00286       /* Keep going if this isn't the final destination */
00287       source = cur->t->dstfmt;
00288    }
00289 
00290    AST_LIST_UNLOCK(&translators);
00291    return head;
00292 }
00293 
00294 /*! \brief do the actual translation */
00295 struct ast_frame *ast_translate(struct ast_trans_pvt *path, struct ast_frame *f, int consume)
00296 {
00297    struct ast_trans_pvt *p = path;
00298    struct ast_frame *out = f;
00299    struct timeval delivery;
00300    int has_timing_info;
00301    long ts;
00302    long len;
00303    int seqno;
00304 
00305    has_timing_info = f->has_timing_info;
00306    ts = f->ts;
00307    len = f->len;
00308    seqno = f->seqno;
00309 
00310    /* XXX hmmm... check this below */
00311    if (!ast_tvzero(f->delivery)) {
00312       if (!ast_tvzero(path->nextin)) {
00313          /* Make sure this is in line with what we were expecting */
00314          if (!ast_tveq(path->nextin, f->delivery)) {
00315             /* The time has changed between what we expected and this
00316                most recent time on the new packet.  If we have a
00317                valid prediction adjust our output time appropriately */
00318             if (!ast_tvzero(path->nextout)) {
00319                path->nextout = ast_tvadd(path->nextout,
00320                           ast_tvsub(f->delivery, path->nextin));
00321             }
00322             path->nextin = f->delivery;
00323          }
00324       } else {
00325          /* This is our first pass.  Make sure the timing looks good */
00326          path->nextin = f->delivery;
00327          path->nextout = f->delivery;
00328       }
00329       /* Predict next incoming sample */
00330       path->nextin = ast_tvadd(path->nextin, ast_samp2tv(f->samples, 8000));
00331    }
00332    delivery = f->delivery;
00333    for ( ; out && p ; p = p->next) {
00334       framein(p, out);
00335       out = p->t->frameout(p);
00336    }
00337    if (consume)
00338       ast_frfree(f);
00339    if (out == NULL)
00340       return NULL;
00341    /* we have a frame, play with times */
00342    if (!ast_tvzero(delivery)) {
00343       /* Regenerate prediction after a discontinuity */
00344       if (ast_tvzero(path->nextout))
00345          path->nextout = ast_tvnow();
00346 
00347       /* Use next predicted outgoing timestamp */
00348       out->delivery = path->nextout;
00349       
00350       /* Predict next outgoing timestamp from samples in this
00351          frame. */
00352       path->nextout = ast_tvadd(path->nextout, ast_samp2tv( out->samples, 8000));
00353    } else {
00354       out->delivery = ast_tv(0, 0);
00355       out->has_timing_info = has_timing_info;
00356       if (has_timing_info) {
00357          out->ts = ts;
00358          out->len = len;
00359          out->seqno = seqno;
00360       }
00361    }
00362    /* Invalidate prediction if we're entering a silence period */
00363    if (out->frametype == AST_FRAME_CNG)
00364       path->nextout = ast_tv(0, 0);
00365    return out;
00366 }
00367 
00368 /*! \brief compute the cost of a single translation step */
00369 static void calc_cost(struct ast_translator *t, int seconds)
00370 {
00371    int sofar=0;
00372    struct ast_trans_pvt *pvt;
00373    struct timeval start;
00374    int cost;
00375 
00376    if (!seconds)
00377       seconds = 1;
00378    
00379    /* If they don't make samples, give them a terrible score */
00380    if (!t->sample) {
00381       ast_log(LOG_WARNING, "Translator '%s' does not produce sample frames.\n", t->name);
00382       t->cost = 99999;
00383       return;
00384    }
00385    pvt = newpvt(t);
00386    if (!pvt) {
00387       ast_log(LOG_WARNING, "Translator '%s' appears to be broken and will probably fail.\n", t->name);
00388       t->cost = 99999;
00389       return;
00390    }
00391    start = ast_tvnow();
00392    /* Call the encoder until we've processed the required number of samples */
00393    while (sofar < seconds * 8000) {
00394       struct ast_frame *f = t->sample();
00395       if (!f) {
00396          ast_log(LOG_WARNING, "Translator '%s' failed to produce a sample frame.\n", t->name);
00397          destroy(pvt);
00398          t->cost = 99999;
00399          return;
00400       }
00401       framein(pvt, f);
00402       ast_frfree(f);
00403       while ((f = t->frameout(pvt))) {
00404          sofar += f->samples;
00405          ast_frfree(f);
00406       }
00407    }
00408    cost = ast_tvdiff_ms(ast_tvnow(), start);
00409    destroy(pvt);
00410    t->cost = cost / seconds;
00411    if (!t->cost)
00412       t->cost = 1;
00413 }
00414 
00415 /*!
00416  * \brief rebuild a translation matrix.
00417  * \note This function expects the list of translators to be locked
00418 */
00419 static void rebuild_matrix(int samples)
00420 {
00421    struct ast_translator *t;
00422    int x;      /* source format index */
00423    int y;      /* intermediate format index */
00424    int z;      /* destination format index */
00425 
00426    if (option_debug)
00427       ast_log(LOG_DEBUG, "Resetting translation matrix\n");
00428 
00429    bzero(tr_matrix, sizeof(tr_matrix));
00430 
00431    /* first, compute all direct costs */
00432    AST_LIST_TRAVERSE(&translators, t, list) {
00433       if (!t->active)
00434          continue;
00435 
00436       x = t->srcfmt;
00437       z = t->dstfmt;
00438 
00439       if (samples)
00440          calc_cost(t, samples);
00441      
00442       if (!tr_matrix[x][z].step || t->cost < tr_matrix[x][z].cost) {
00443          tr_matrix[x][z].step = t;
00444          tr_matrix[x][z].cost = t->cost;
00445       }
00446    }
00447 
00448    /*
00449     * For each triple x, y, z of distinct formats, check if there is
00450     * a path from x to z through y which is cheaper than what is
00451     * currently known, and in case, update the matrix.
00452     * Repeat until the matrix is stable.
00453     */
00454    for (;;) {
00455       int changed = 0;
00456       for (x = 0; x < MAX_FORMAT; x++) {      /* source format */
00457          for (y=0; y < MAX_FORMAT; y++) {    /* intermediate format */
00458             if (x == y)                     /* skip ourselves */
00459                continue;
00460 
00461             for (z=0; z<MAX_FORMAT; z++) {  /* dst format */
00462                int newcost;
00463 
00464                if (z == x || z == y)       /* skip null conversions */
00465                   continue;
00466                if (!tr_matrix[x][y].step)  /* no path from x to y */
00467                   continue;
00468                if (!tr_matrix[y][z].step)  /* no path from y to z */
00469                   continue;
00470                newcost = tr_matrix[x][y].cost + tr_matrix[y][z].cost;
00471                if (tr_matrix[x][z].step && newcost >= tr_matrix[x][z].cost)
00472                   continue;               /* x->y->z is more expensive than
00473                                            * the existing path */
00474                /* ok, we can get from x to z via y with a cost that
00475                   is the sum of the transition from x to y and
00476                   from y to z */
00477                    
00478                tr_matrix[x][z].step = tr_matrix[x][y].step;
00479                tr_matrix[x][z].cost = newcost;
00480                tr_matrix[x][z].multistep = 1;
00481                if (option_debug)
00482                   ast_log(LOG_DEBUG, "Discovered %d cost path from %s to %s, via %d\n", tr_matrix[x][z].cost, ast_getformatname(x), ast_getformatname(z), y);
00483                changed++;
00484             }
00485          }
00486       }
00487       if (!changed)
00488          break;
00489    }
00490 }
00491 
00492 /*! \brief CLI "show translation" command handler */
00493 static int show_translation_deprecated(int fd, int argc, char *argv[])
00494 {
00495 #define SHOW_TRANS 13
00496    int x, y, z;
00497    int curlen = 0, longest = 0;
00498 
00499    if (argc > 4) 
00500       return RESULT_SHOWUSAGE;
00501 
00502    AST_LIST_LOCK(&translators);  
00503    
00504    if (argv[2] && !strcasecmp(argv[2], "recalc")) {
00505       z = argv[3] ? atoi(argv[3]) : 1;
00506 
00507       if (z <= 0) {
00508          ast_cli(fd, "         C'mon let's be serious here... defaulting to 1.\n");
00509          z = 1;
00510       }
00511 
00512       if (z > MAX_RECALC) {
00513          ast_cli(fd, "         Maximum limit of recalc exceeded by %d, truncating value to %d\n", z - MAX_RECALC, MAX_RECALC);
00514          z = MAX_RECALC;
00515       }
00516       ast_cli(fd, "         Recalculating Codec Translation (number of sample seconds: %d)\n\n", z);
00517       rebuild_matrix(z);
00518    }
00519 
00520    ast_cli(fd, "         Translation times between formats (in milliseconds) for one second of data\n");
00521    ast_cli(fd, "          Source Format (Rows) Destination Format (Columns)\n\n");
00522    /* Get the length of the longest (usable?) codec name, so we know how wide the left side should be */
00523    for (x = 0; x < SHOW_TRANS; x++) {
00524       curlen = strlen(ast_getformatname(1 << (x + 1)));
00525       if (curlen > longest)
00526          longest = curlen;
00527    }
00528    for (x = -1; x < SHOW_TRANS; x++) {
00529       char line[120];
00530       char *buf = line;
00531       size_t left = sizeof(line) - 1;  /* one initial space */
00532       /* next 2 lines run faster than using ast_build_string() */
00533       *buf++ = ' ';
00534       *buf = '\0';
00535       for (y = -1; y < SHOW_TRANS; y++) {
00536          curlen = strlen(ast_getformatname(1 << (y)));
00537 
00538          if (x >= 0 && y >= 0 && tr_matrix[x][y].step) {
00539             /* XXX 999 is a little hackish
00540                We don't want this number being larger than the shortest (or current) codec
00541                For now, that is "gsm" */
00542             ast_build_string(&buf, &left, "%*d", curlen + 1, tr_matrix[x][y].cost > 999 ? 0 : tr_matrix[x][y].cost);
00543          } else if (x == -1 && y >= 0) {
00544             /* Top row - use a dynamic size */
00545             ast_build_string(&buf, &left, "%*s", curlen + 1, ast_getformatname(1 << (x + y + 1)) );
00546          } else if (y == -1 && x >= 0) {
00547             /* Left column - use a static size. */
00548             ast_build_string(&buf, &left, "%*s", longest, ast_getformatname(1 << (x + y + 1)) );
00549          } else if (x >= 0 && y >= 0) {
00550             ast_build_string(&buf, &left, "%*s", curlen + 1, "-");
00551          } else {
00552             ast_build_string(&buf, &left, "%*s", longest, "");
00553          }
00554       }
00555       ast_build_string(&buf, &left, "\n");
00556       ast_cli(fd, line);         
00557    }
00558    AST_LIST_UNLOCK(&translators);
00559    return RESULT_SUCCESS;
00560 }
00561 
00562 static int show_translation(int fd, int argc, char *argv[])
00563 {
00564    int x, y, z;
00565    int curlen = 0, longest = 0;
00566 
00567    if (argc > 5)
00568       return RESULT_SHOWUSAGE;
00569 
00570    AST_LIST_LOCK(&translators);  
00571    
00572    if (argv[3] && !strcasecmp(argv[3], "recalc")) {
00573       z = argv[4] ? atoi(argv[4]) : 1;
00574 
00575       if (z <= 0) {
00576          ast_cli(fd, "         C'mon let's be serious here... defaulting to 1.\n");
00577          z = 1;
00578       }
00579 
00580       if (z > MAX_RECALC) {
00581          ast_cli(fd, "         Maximum limit of recalc exceeded by %d, truncating value to %d\n", z - MAX_RECALC, MAX_RECALC);
00582          z = MAX_RECALC;
00583       }
00584       ast_cli(fd, "         Recalculating Codec Translation (number of sample seconds: %d)\n\n", z);
00585       rebuild_matrix(z);
00586    }
00587 
00588    ast_cli(fd, "         Translation times between formats (in milliseconds) for one second of data\n");
00589    ast_cli(fd, "          Source Format (Rows) Destination Format (Columns)\n\n");
00590    /* Get the length of the longest (usable?) codec name, so we know how wide the left side should be */
00591    for (x = 0; x < SHOW_TRANS; x++) {
00592       curlen = strlen(ast_getformatname(1 << (x + 1)));
00593       if (curlen > longest)
00594          longest = curlen;
00595    }
00596    for (x = -1; x < SHOW_TRANS; x++) {
00597       char line[120];
00598       char *buf = line;
00599       size_t left = sizeof(line) - 1;  /* one initial space */
00600       /* next 2 lines run faster than using ast_build_string() */
00601       *buf++ = ' ';
00602       *buf = '\0';
00603       for (y = -1; y < SHOW_TRANS; y++) {
00604          curlen = strlen(ast_getformatname(1 << (y)));
00605 
00606          if (x >= 0 && y >= 0 && tr_matrix[x][y].step) {
00607             /* XXX 999 is a little hackish
00608                We don't want this number being larger than the shortest (or current) codec
00609                For now, that is "gsm" */
00610             ast_build_string(&buf, &left, "%*d", curlen + 1, tr_matrix[x][y].cost > 999 ? 0 : tr_matrix[x][y].cost);
00611          } else if (x == -1 && y >= 0) {
00612             /* Top row - use a dynamic size */
00613             ast_build_string(&buf, &left, "%*s", curlen + 1, ast_getformatname(1 << (x + y + 1)) );
00614          } else if (y == -1 && x >= 0) {
00615             /* Left column - use a static size. */
00616             ast_build_string(&buf, &left, "%*s", longest, ast_getformatname(1 << (x + y + 1)) );
00617          } else if (x >= 0 && y >= 0) {
00618             ast_build_string(&buf, &left, "%*s", curlen + 1, "-");
00619          } else {
00620             ast_build_string(&buf, &left, "%*s", longest, "");
00621          }
00622       }
00623       ast_build_string(&buf, &left, "\n");
00624       ast_cli(fd, line);         
00625    }
00626    AST_LIST_UNLOCK(&translators);
00627    return RESULT_SUCCESS;
00628 }
00629 
00630 static char show_trans_usage[] =
00631 "Usage: core show translation [recalc] [<recalc seconds>]\n"
00632 "       Displays known codec translators and the cost associated\n"
00633 "with each conversion.  If the argument 'recalc' is supplied along\n"
00634 "with optional number of seconds to test a new test will be performed\n"
00635 "as the chart is being displayed.\n";
00636 
00637 static struct ast_cli_entry cli_show_translation_deprecated = {
00638    { "show", "translation", NULL },
00639    show_translation_deprecated, NULL,
00640    NULL };
00641 
00642 static struct ast_cli_entry cli_translate[] = {
00643    { { "core", "show", "translation", NULL },
00644    show_translation, "Display translation matrix",
00645    show_trans_usage, NULL, &cli_show_translation_deprecated },
00646 };
00647 
00648 /*! \brief register codec translator */
00649 int __ast_register_translator(struct ast_translator *t, struct ast_module *mod)
00650 {
00651    static int added_cli = 0;
00652    struct ast_translator *u;
00653 
00654    if (!mod) {
00655       ast_log(LOG_WARNING, "Missing module pointer, you need to supply one\n");
00656       return -1;
00657    }
00658 
00659    if (!t->buf_size) {
00660       ast_log(LOG_WARNING, "empty buf size, you need to supply one\n");
00661       return -1;
00662    }
00663 
00664    t->module = mod;
00665 
00666    t->srcfmt = powerof(t->srcfmt);
00667    t->dstfmt = powerof(t->dstfmt);
00668    t->active = 1;
00669 
00670    if (t->plc_samples) {
00671       if (t->buffer_samples < t->plc_samples) {
00672          ast_log(LOG_WARNING, "plc_samples %d buffer_samples %d\n",
00673             t->plc_samples, t->buffer_samples);
00674          return -1;
00675       }
00676       if (t->dstfmt != powerof(AST_FORMAT_SLINEAR))
00677          ast_log(LOG_WARNING, "plc_samples %d format %x\n",
00678             t->plc_samples, t->dstfmt);
00679    }
00680    if (t->srcfmt >= MAX_FORMAT) {
00681       ast_log(LOG_WARNING, "Source format %s is larger than MAX_FORMAT\n", ast_getformatname(t->srcfmt));
00682       return -1;
00683    }
00684 
00685    if (t->dstfmt >= MAX_FORMAT) {
00686       ast_log(LOG_WARNING, "Destination format %s is larger than MAX_FORMAT\n", ast_getformatname(t->dstfmt));
00687       return -1;
00688    }
00689 
00690    if (t->buf_size) {
00691                /*
00692       * Align buf_size properly, rounding up to the machine-specific
00693       * alignment for pointers.
00694       */
00695       struct _test_align { void *a, *b; } p;
00696       int align = (char *)&p.b - (char *)&p.a;
00697 
00698       t->buf_size = ((t->buf_size + align - 1) / align) * align;
00699    }
00700 
00701    if (t->frameout == NULL)
00702       t->frameout = default_frameout;
00703   
00704    calc_cost(t, 1);
00705 
00706    if (option_verbose > 1) {
00707       char tmp[80];
00708 
00709       ast_verbose(VERBOSE_PREFIX_2 "Registered translator '%s' from format %s to %s, cost %d\n",
00710              term_color(tmp, t->name, COLOR_MAGENTA, COLOR_BLACK, sizeof(tmp)),
00711              ast_getformatname(1 << t->srcfmt), ast_getformatname(1 << t->dstfmt), t->cost);
00712    }
00713 
00714    if (!added_cli) {
00715       ast_cli_register_multiple(cli_translate, sizeof(cli_translate) / sizeof(struct ast_cli_entry));
00716       added_cli++;
00717    }
00718 
00719    AST_LIST_LOCK(&translators);
00720 
00721    /* find any existing translators that provide this same srcfmt/dstfmt,
00722       and put this one in order based on cost */
00723    AST_LIST_TRAVERSE_SAFE_BEGIN(&translators, u, list) {
00724       if ((u->srcfmt == t->srcfmt) &&
00725           (u->dstfmt == t->dstfmt) &&
00726           (u->cost > t->cost)) {
00727          AST_LIST_INSERT_BEFORE_CURRENT(&translators, t, list);
00728          t = NULL;
00729       }
00730    }
00731    AST_LIST_TRAVERSE_SAFE_END;
00732 
00733    /* if no existing translator was found for this format combination,
00734       add it to the beginning of the list */
00735    if (t)
00736       AST_LIST_INSERT_HEAD(&translators, t, list);
00737 
00738    rebuild_matrix(0);
00739 
00740    AST_LIST_UNLOCK(&translators);
00741 
00742    return 0;
00743 }
00744 
00745 /*! \brief unregister codec translator */
00746 int ast_unregister_translator(struct ast_translator *t)
00747 {
00748    char tmp[80];
00749    struct ast_translator *u;
00750    int found = 0;
00751 
00752    AST_LIST_LOCK(&translators);
00753    AST_LIST_TRAVERSE_SAFE_BEGIN(&translators, u, list) {
00754       if (u == t) {
00755          AST_LIST_REMOVE_CURRENT(&translators, list);
00756          if (option_verbose > 1)
00757             ast_verbose(VERBOSE_PREFIX_2 "Unregistered translator '%s' from format %s to %s\n", term_color(tmp, t->name, COLOR_MAGENTA, COLOR_BLACK, sizeof(tmp)), ast_getformatname(1 << t->srcfmt), ast_getformatname(1 << t->dstfmt));
00758          found = 1;
00759          break;
00760       }
00761    }
00762    AST_LIST_TRAVERSE_SAFE_END;
00763 
00764    if (found)
00765       rebuild_matrix(0);
00766 
00767    AST_LIST_UNLOCK(&translators);
00768 
00769    return (u ? 0 : -1);
00770 }
00771 
00772 void ast_translator_activate(struct ast_translator *t)
00773 {
00774    AST_LIST_LOCK(&translators);
00775    t->active = 1;
00776    rebuild_matrix(0);
00777    AST_LIST_UNLOCK(&translators);
00778 }
00779 
00780 void ast_translator_deactivate(struct ast_translator *t)
00781 {
00782    AST_LIST_LOCK(&translators);
00783    t->active = 0;
00784    rebuild_matrix(0);
00785    AST_LIST_UNLOCK(&translators);
00786 }
00787 
00788 /*! \brief Calculate our best translator source format, given costs, and a desired destination */
00789 int ast_translator_best_choice(int *dst, int *srcs)
00790 {
00791    int x,y;
00792    int best = -1;
00793    int bestdst = 0;
00794    int cur, cursrc;
00795    int besttime = INT_MAX;
00796    int beststeps = INT_MAX;
00797    int common = (*dst) & (*srcs);   /* are there common formats ? */
00798 
00799    if (common) { /* yes, pick one and return */
00800       for (cur = 1, y = 0; y < MAX_FORMAT; cur <<= 1, y++) {
00801          if (cur & common) /* guaranteed to find one */
00802             break;
00803       }
00804       /* We are done, this is a common format to both. */
00805       *srcs = *dst = cur;
00806       return 0;
00807    } else { /* No, we will need to translate */
00808       AST_LIST_LOCK(&translators);
00809       for (cur = 1, y = 0; y < MAX_FORMAT; cur <<= 1, y++) {
00810          if (! (cur & *dst))
00811             continue;
00812          for (cursrc = 1, x = 0; x < MAX_FORMAT; cursrc <<= 1, x++) {
00813             if (!(*srcs & cursrc) || !tr_matrix[x][y].step ||
00814                 tr_matrix[x][y].cost >  besttime)
00815                continue;   /* not existing or no better */
00816             if (tr_matrix[x][y].cost < besttime ||
00817                 tr_matrix[x][y].multistep < beststeps) {
00818                /* better than what we have so far */
00819                best = cursrc;
00820                bestdst = cur;
00821                besttime = tr_matrix[x][y].cost;
00822                beststeps = tr_matrix[x][y].multistep;
00823             }
00824          }
00825       }
00826       AST_LIST_UNLOCK(&translators);
00827       if (best > -1) {
00828          *srcs = best;
00829          *dst = bestdst;
00830          best = 0;
00831       }
00832       return best;
00833    }
00834 }
00835 
00836 unsigned int ast_translate_path_steps(unsigned int dest, unsigned int src)
00837 {
00838    unsigned int res = -1;
00839 
00840    /* convert bitwise format numbers into array indices */
00841    src = powerof(src);
00842    dest = powerof(dest);
00843 
00844    AST_LIST_LOCK(&translators);
00845 
00846    if (tr_matrix[src][dest].step)
00847       res = tr_matrix[src][dest].multistep + 1;
00848 
00849    AST_LIST_UNLOCK(&translators);
00850 
00851    return res;
00852 }
00853 
00854 unsigned int ast_translate_available_formats(unsigned int dest, unsigned int src)
00855 {
00856    unsigned int res = dest;
00857    unsigned int x;
00858    unsigned int src_audio = src & AST_FORMAT_AUDIO_MASK;
00859    unsigned int src_video = src & AST_FORMAT_VIDEO_MASK;
00860 
00861    /* if we don't have a source format, we just have to try all
00862       possible destination formats */
00863    if (!src)
00864       return dest;
00865 
00866    /* If we have a source audio format, get its format index */
00867    if (src_audio)
00868       src_audio = powerof(src_audio);
00869 
00870    /* If we have a source video format, get its format index */
00871    if (src_video)
00872       src_video = powerof(src_video);
00873 
00874    AST_LIST_LOCK(&translators);
00875 
00876    /* For a given source audio format, traverse the list of
00877       known audio formats to determine whether there exists
00878       a translation path from the source format to the
00879       destination format. */
00880    for (x = 1; src_audio && x < AST_FORMAT_MAX_AUDIO; x <<= 1) {
00881       /* if this is not a desired format, nothing to do */
00882       if (!dest & x)
00883          continue;
00884 
00885       /* if the source is supplying this format, then
00886          we can leave it in the result */
00887       if (src & x)
00888          continue;
00889 
00890       /* if we don't have a translation path from the src
00891          to this format, remove it from the result */
00892       if (!tr_matrix[src_audio][powerof(x)].step) {
00893          res &= ~x;
00894          continue;
00895       }
00896 
00897       /* now check the opposite direction */
00898       if (!tr_matrix[powerof(x)][src_audio].step)
00899          res &= ~x;
00900    }
00901 
00902    /* For a given source video format, traverse the list of
00903       known video formats to determine whether there exists
00904       a translation path from the source format to the
00905       destination format. */
00906    for (; src_video && x < AST_FORMAT_MAX_VIDEO; x <<= 1) {
00907       /* if this is not a desired format, nothing to do */
00908       if (!dest & x)
00909          continue;
00910 
00911       /* if the source is supplying this format, then
00912          we can leave it in the result */
00913       if (src & x)
00914          continue;
00915 
00916       /* if we don't have a translation path from the src
00917          to this format, remove it from the result */
00918       if (!tr_matrix[src_video][powerof(x)].step) {
00919          res &= ~x;
00920          continue;
00921       }
00922 
00923       /* now check the opposite direction */
00924       if (!tr_matrix[powerof(x)][src_video].step)
00925          res &= ~x;
00926    }
00927 
00928    AST_LIST_UNLOCK(&translators);
00929 
00930    return res;
00931 }

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