libavutil/opt.c

   1 /*
   2  * AVOptions
   3  * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file
  24  * AVOptions
  25  * @author Michael Niedermayer <michaelni@gmx.at>
  26  */
  27
  28 #include "avstring.h"
  29 #include "avutil.h"
  30 #include "common.h"
  31 #include "dict.h"
  32 #include "eval.h"
  33 #include "log.h"
  34 #include "mathematics.h"
  35 #include "opt.h"
  36
  37 const AVOption *av_opt_next(const void *obj, const AVOption *last)
  38 {
  39     AVClass *class = *(AVClass **)obj;
  40     if (!last && class->option && class->option[0].name)
  41         return class->option;
  42     if (last && last[1].name)
  43         return ++last;
  44     return NULL;
  45 }
  46
  47 static int read_number(const AVOption *o, const void *dst, double *num, int *den, int64_t *intnum)
  48 {
  49     switch (o->type) {
  50     case AV_OPT_TYPE_FLAGS:
  51         *intnum = *(unsigned int *)dst;
  52         return 0;
  53     case AV_OPT_TYPE_INT:
  54         *intnum = *(int *)dst;
  55         return 0;
  56     case AV_OPT_TYPE_INT64:
  57         *intnum = *(int64_t *)dst;
  58         return 0;
  59     case AV_OPT_TYPE_FLOAT:
  60         *num = *(float *)dst;
  61         return 0;
  62     case AV_OPT_TYPE_DOUBLE:
  63         *num = *(double *)dst;
  64         return 0;
  65     case AV_OPT_TYPE_RATIONAL:
  66         *intnum = ((AVRational *)dst)->num;
  67         *den    = ((AVRational *)dst)->den;
  68         return 0;
  69     }
  70     return AVERROR(EINVAL);
  71 }
  72
  73 static int write_number(void *obj, const AVOption *o, void *dst, double num, int den, int64_t intnum)
  74 {
  75     if (o->type != AV_OPT_TYPE_FLAGS &&
  76         (o->max * den < num * intnum || o->min * den > num * intnum)) {
  77         av_log(obj, AV_LOG_ERROR, "Value %f for parameter '%s' out of range\n",
  78                num * intnum / den, o->name);
  79         return AVERROR(ERANGE);
  80     }
  81
  82     switch (o->type) {
  83     case AV_OPT_TYPE_FLAGS:
  84     case AV_OPT_TYPE_INT:
  85         *(int *)dst = llrint(num / den) * intnum;
  86         break;
  87     case AV_OPT_TYPE_INT64:
  88         *(int64_t *)dst = llrint(num / den) * intnum;
  89         break;
  90     case AV_OPT_TYPE_FLOAT:
  91         *(float *)dst = num * intnum / den;
  92         break;
  93     case AV_OPT_TYPE_DOUBLE:
  94         *(double *)dst = num * intnum / den;
  95         break;
  96     case AV_OPT_TYPE_RATIONAL:
  97         if ((int) num == num)
  98             *(AVRational *)dst = (AVRational) { num *intnum, den };
  99         else
 100             *(AVRational *)dst = av_d2q(num * intnum / den, 1 << 24);
 101         break;
 102     default:
 103         return AVERROR(EINVAL);
 104     }
 105     return 0;
 106 }
 107
 108 static const double const_values[] = {
 109     M_PI,
 110     M_E,
 111     FF_QP2LAMBDA,
 112     0
 113 };
 114
 115 static const char *const const_names[] = {
 116     "PI",
 117     "E",
 118     "QP2LAMBDA",
 119     0
 120 };
 121
 122 static int hexchar2int(char c)
 123 {
 124     if (c >= '0' && c <= '9')
 125         return c - '0';
 126     if (c >= 'a' && c <= 'f')
 127         return c - 'a' + 10;
 128     if (c >= 'A' && c <= 'F')
 129         return c - 'A' + 10;
 130     return -1;
 131 }
 132
 133 static int set_string_binary(void *obj, const AVOption *o, const char *val, uint8_t **dst)
 134 {
 135     int *lendst = (int *)(dst + 1);
 136     uint8_t *bin, *ptr;
 137     int len = strlen(val);
 138
 139     av_freep(dst);
 140     *lendst = 0;
 141
 142     if (len & 1)
 143         return AVERROR(EINVAL);
 144     len /= 2;
 145
 146     ptr = bin = av_malloc(len);
 147     if (!ptr)
 148         return AVERROR(ENOMEM);
 149     while (*val) {
 150         int a = hexchar2int(*val++);
 151         int b = hexchar2int(*val++);
 152         if (a < 0 || b < 0) {
 153             av_free(bin);
 154             return AVERROR(EINVAL);
 155         }
 156         *ptr++ = (a << 4) | b;
 157     }
 158     *dst    = bin;
 159     *lendst = len;
 160
 161     return 0;
 162 }
 163
 164 static int set_string(void *obj, const AVOption *o, const char *val, uint8_t **dst)
 165 {
 166     av_freep(dst);
 167     *dst = av_strdup(val);
 168     return *dst ? 0 : AVERROR(ENOMEM);
 169 }
 170
 171 #define DEFAULT_NUMVAL(opt) ((opt->type == AV_OPT_TYPE_INT64 || \
 172                               opt->type == AV_OPT_TYPE_CONST || \
 173                               opt->type == AV_OPT_TYPE_FLAGS || \
 174                               opt->type == AV_OPT_TYPE_INT)     \
 175                              ? opt->default_val.i64             \
 176                              : opt->default_val.dbl)
 177
 178 static int set_string_number(void *obj, void *target_obj, const AVOption *o, const char *val, void *dst)
 179 {
 180     int ret = 0, notfirst = 0;
 181     for (;;) {
 182         int i, den = 1;
 183         char buf[256];
 184         int cmd = 0;
 185         double d, num = 1;
 186         int64_t intnum = 1;
 187
 188         i = 0;
 189         if (*val == '+' || *val == '-') {
 190             if (o->type == AV_OPT_TYPE_FLAGS)
 191                 cmd = *(val++);
 192             else if (!notfirst)
 193                 buf[i++] = *val;
 194         }
 195
 196         for (; i < sizeof(buf) - 1 && val[i] && val[i] != '+' && val[i] != '-'; i++)
 197             buf[i] = val[i];
 198         buf[i] = 0;
 199
 200         {
 201             const AVOption *o_named = av_opt_find(target_obj, buf, o->unit, 0, 0);
 202             if (o_named && o_named->type == AV_OPT_TYPE_CONST)
 203                 d = DEFAULT_NUMVAL(o_named);
 204             else if (!strcmp(buf, "default"))
 205                 d = DEFAULT_NUMVAL(o);
 206             else if (!strcmp(buf, "max"))
 207                 d = o->max;
 208             else if (!strcmp(buf, "min"))
 209                 d = o->min;
 210             else if (!strcmp(buf, "none"))
 211                 d = 0;
 212             else if (!strcmp(buf, "all"))
 213                 d = ~0;
 214             else {
 215                 int res = av_expr_parse_and_eval(&d, buf, const_names, const_values, NULL, NULL, NULL, NULL, NULL, 0, obj);
 216                 if (res < 0) {
 217                     av_log(obj, AV_LOG_ERROR, "Unable to parse option value \"%s\"\n", val);
 218                     return res;
 219                 }
 220             }
 221         }
 222         if (o->type == AV_OPT_TYPE_FLAGS) {
 223             read_number(o, dst, NULL, NULL, &intnum);
 224             if (cmd == '+')
 225                 d = intnum | (int64_t)d;
 226             else if (cmd == '-')
 227                 d = intnum & ~(int64_t)d;
 228         } else {
 229             read_number(o, dst, &num, &den, &intnum);
 230             if (cmd == '+')
 231                 d = notfirst * num * intnum / den + d;
 232             else if (cmd == '-')
 233                 d = notfirst * num * intnum / den - d;
 234         }
 235
 236         if ((ret = write_number(obj, o, dst, d, 1, 1)) < 0)
 237             return ret;
 238         val += i;
 239         if (!*val)
 240             return 0;
 241         notfirst = 1;
 242     }
 243 }
 244
 245 int av_opt_set(void *obj, const char *name, const char *val, int search_flags)
 246 {
 247     void *dst, *target_obj;
 248     const AVOption *o = av_opt_find2(obj, name, NULL, 0, search_flags, &target_obj);
 249     if (!o || !target_obj)
 250         return AVERROR_OPTION_NOT_FOUND;
 251     if (!val || o->flags & AV_OPT_FLAG_READONLY)
 252         return AVERROR(EINVAL);
 253
 254     dst = ((uint8_t *)target_obj) + o->offset;
 255     switch (o->type) {
 256     case AV_OPT_TYPE_STRING:
 257         return set_string(obj, o, val, dst);
 258     case AV_OPT_TYPE_BINARY:
 259         return set_string_binary(obj, o, val, dst);
 260     case AV_OPT_TYPE_FLAGS:
 261     case AV_OPT_TYPE_INT:
 262     case AV_OPT_TYPE_INT64:
 263     case AV_OPT_TYPE_FLOAT:
 264     case AV_OPT_TYPE_DOUBLE:
 265     case AV_OPT_TYPE_RATIONAL:
 266         return set_string_number(obj, target_obj, o, val, dst);
 267     }
 268
 269     av_log(obj, AV_LOG_ERROR, "Invalid option type.\n");
 270     return AVERROR(EINVAL);
 271 }
 272
 273 #define OPT_EVAL_NUMBER(name, opttype, vartype)                         \
 274 int av_opt_eval_ ## name(void *obj, const AVOption *o,                  \
 275                          const char *val, vartype *name ## _out)        \
 276 {                                                                       \
 277     if (!o || o->type != opttype || o->flags & AV_OPT_FLAG_READONLY)    \
 278         return AVERROR(EINVAL);                                         \
 279     return set_string_number(obj, obj, o, val, name ## _out);           \
 280 }
 281
 282 OPT_EVAL_NUMBER(flags,  AV_OPT_TYPE_FLAGS,    int)
 283 OPT_EVAL_NUMBER(int,    AV_OPT_TYPE_INT,      int)
 284 OPT_EVAL_NUMBER(int64,  AV_OPT_TYPE_INT64,    int64_t)
 285 OPT_EVAL_NUMBER(float,  AV_OPT_TYPE_FLOAT,    float)
 286 OPT_EVAL_NUMBER(double, AV_OPT_TYPE_DOUBLE,   double)
 287 OPT_EVAL_NUMBER(q,      AV_OPT_TYPE_RATIONAL, AVRational)
 288
 289 static int set_number(void *obj, const char *name, double num, int den, int64_t intnum,
 290                       int search_flags)
 291 {
 292     void *dst, *target_obj;
 293     const AVOption *o = av_opt_find2(obj, name, NULL, 0, search_flags, &target_obj);
 294
 295     if (!o || !target_obj)
 296         return AVERROR_OPTION_NOT_FOUND;
 297
 298     if (o->flags & AV_OPT_FLAG_READONLY)
 299         return AVERROR(EINVAL);
 300
 301     dst = ((uint8_t *)target_obj) + o->offset;
 302     return write_number(obj, o, dst, num, den, intnum);
 303 }
 304
 305 int av_opt_set_int(void *obj, const char *name, int64_t val, int search_flags)
 306 {
 307     return set_number(obj, name, 1, 1, val, search_flags);
 308 }
 309
 310 int av_opt_set_double(void *obj, const char *name, double val, int search_flags)
 311 {
 312     return set_number(obj, name, val, 1, 1, search_flags);
 313 }
 314
 315 int av_opt_set_q(void *obj, const char *name, AVRational val, int search_flags)
 316 {
 317     return set_number(obj, name, val.num, val.den, 1, search_flags);
 318 }
 319
 320 int av_opt_set_bin(void *obj, const char *name, const uint8_t *val, int len, int search_flags)
 321 {
 322     void *target_obj;
 323     const AVOption *o = av_opt_find2(obj, name, NULL, 0, search_flags, &target_obj);
 324     uint8_t *ptr;
 325     uint8_t **dst;
 326     int *lendst;
 327
 328     if (!o || !target_obj)
 329         return AVERROR_OPTION_NOT_FOUND;
 330
 331     if (o->type != AV_OPT_TYPE_BINARY || o->flags & AV_OPT_FLAG_READONLY)
 332         return AVERROR(EINVAL);
 333
 334     ptr = av_malloc(len);
 335     if (!ptr)
 336         return AVERROR(ENOMEM);
 337
 338     dst    = (uint8_t **)(((uint8_t *)target_obj) + o->offset);
 339     lendst = (int *)(dst + 1);
 340
 341     av_free(*dst);
 342     *dst    = ptr;
 343     *lendst = len;
 344     memcpy(ptr, val, len);
 345
 346     return 0;
 347 }
 348
 349 int av_opt_set_dict_val(void *obj, const char *name, const AVDictionary *val,
 350                         int search_flags)
 351 {
 352     void *target_obj;
 353     AVDictionary **dst;
 354     const AVOption *o = av_opt_find2(obj, name, NULL, 0, search_flags, &target_obj);
 355
 356     if (!o || !target_obj)
 357         return AVERROR_OPTION_NOT_FOUND;
 358     if (o->flags & AV_OPT_FLAG_READONLY)
 359         return AVERROR(EINVAL);
 360
 361     dst = (AVDictionary **)(((uint8_t *)target_obj) + o->offset);
 362     av_dict_free(dst);
 363     av_dict_copy(dst, val, 0);
 364
 365     return 0;
 366 }
 367
 368 int av_opt_get(void *obj, const char *name, int search_flags, uint8_t **out_val)
 369 {
 370     void *dst, *target_obj;
 371     const AVOption *o = av_opt_find2(obj, name, NULL, 0, search_flags, &target_obj);
 372     uint8_t *bin, buf[128];
 373     int len, i, ret;
 374
 375     if (!o || !target_obj)
 376         return AVERROR_OPTION_NOT_FOUND;
 377
 378     dst = (uint8_t *)target_obj + o->offset;
 379
 380     buf[0] = 0;
 381     switch (o->type) {
 382     case AV_OPT_TYPE_FLAGS:
 383         ret = snprintf(buf, sizeof(buf), "0x%08X", *(int *)dst);
 384         break;
 385     case AV_OPT_TYPE_INT:
 386         ret = snprintf(buf, sizeof(buf), "%d", *(int *)dst);
 387         break;
 388     case AV_OPT_TYPE_INT64:
 389         ret = snprintf(buf, sizeof(buf), "%" PRId64, *(int64_t *)dst);
 390         break;
 391     case AV_OPT_TYPE_FLOAT:
 392         ret = snprintf(buf, sizeof(buf), "%f", *(float *)dst);
 393         break;
 394     case AV_OPT_TYPE_DOUBLE:
 395         ret = snprintf(buf, sizeof(buf), "%f", *(double *)dst);
 396         break;
 397     case AV_OPT_TYPE_RATIONAL:
 398         ret = snprintf(buf, sizeof(buf), "%d/%d", ((AVRational *)dst)->num,
 399                        ((AVRational *)dst)->den);
 400         break;
 401     case AV_OPT_TYPE_STRING:
 402         if (*(uint8_t **)dst)
 403             *out_val = av_strdup(*(uint8_t **)dst);
 404         else
 405             *out_val = av_strdup("");
 406         return *out_val ? 0 : AVERROR(ENOMEM);
 407     case AV_OPT_TYPE_BINARY:
 408         len = *(int *)(((uint8_t *)dst) + sizeof(uint8_t *));
 409         if ((uint64_t)len * 2 + 1 > INT_MAX)
 410             return AVERROR(EINVAL);
 411         if (!(*out_val = av_malloc(len * 2 + 1)))
 412             return AVERROR(ENOMEM);
 413         bin = *(uint8_t **)dst;
 414         for (i = 0; i < len; i++)
 415             snprintf(*out_val + i * 2, 3, "%02X", bin[i]);
 416         return 0;
 417     default:
 418         return AVERROR(EINVAL);
 419     }
 420
 421     if (ret >= sizeof(buf))
 422         return AVERROR(EINVAL);
 423     *out_val = av_strdup(buf);
 424     return *out_val ? 0 : AVERROR(ENOMEM);
 425 }
 426
 427 static int get_number(void *obj, const char *name, double *num, int *den, int64_t *intnum,
 428                       int search_flags)
 429 {
 430     void *dst, *target_obj;
 431     const AVOption *o = av_opt_find2(obj, name, NULL, 0, search_flags, &target_obj);
 432     if (!o || !target_obj)
 433         goto error;
 434
 435     dst = ((uint8_t *)target_obj) + o->offset;
 436
 437     return read_number(o, dst, num, den, intnum);
 438
 439 error:
 440     *den    =
 441     *intnum = 0;
 442     return -1;
 443 }
 444
 445 int av_opt_get_int(void *obj, const char *name, int search_flags, int64_t *out_val)
 446 {
 447     int64_t intnum = 1;
 448     double num = 1;
 449     int ret, den = 1;
 450
 451     if ((ret = get_number(obj, name, &num, &den, &intnum, search_flags)) < 0)
 452         return ret;
 453     *out_val = num * intnum / den;
 454     return 0;
 455 }
 456
 457 int av_opt_get_double(void *obj, const char *name, int search_flags, double *out_val)
 458 {
 459     int64_t intnum = 1;
 460     double num = 1;
 461     int ret, den = 1;
 462
 463     if ((ret = get_number(obj, name, &num, &den, &intnum, search_flags)) < 0)
 464         return ret;
 465     *out_val = num * intnum / den;
 466     return 0;
 467 }
 468
 469 int av_opt_get_q(void *obj, const char *name, int search_flags, AVRational *out_val)
 470 {
 471     int64_t intnum = 1;
 472     double num = 1;
 473     int ret, den = 1;
 474
 475     if ((ret = get_number(obj, name, &num, &den, &intnum, search_flags)) < 0)
 476         return ret;
 477
 478     if (num == 1.0 && (int)intnum == intnum)
 479         *out_val = (AVRational) { intnum, den };
 480     else
 481         *out_val = av_d2q(num * intnum / den, 1 << 24);
 482     return 0;
 483 }
 484
 485 int av_opt_get_dict_val(void *obj, const char *name, int search_flags, AVDictionary **out_val)
 486 {
 487     void *target_obj;
 488     AVDictionary *src;
 489     const AVOption *o = av_opt_find2(obj, name, NULL, 0, search_flags, &target_obj);
 490
 491     if (!o || !target_obj)
 492         return AVERROR_OPTION_NOT_FOUND;
 493     if (o->type != AV_OPT_TYPE_DICT)
 494         return AVERROR(EINVAL);
 495
 496     src = *(AVDictionary **)(((uint8_t *)target_obj) + o->offset);
 497     av_dict_copy(out_val, src, 0);
 498
 499     return 0;
 500 }
 501
 502 int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name)
 503 {
 504     const AVOption *field = av_opt_find(obj, field_name, NULL, 0, 0);
 505     const AVOption *flag  = av_opt_find(obj, flag_name,
 506                                         field ? field->unit : NULL, 0, 0);
 507     int64_t res;
 508
 509     if (!field || !flag || flag->type != AV_OPT_TYPE_CONST ||
 510         av_opt_get_int(obj, field_name, 0, &res) < 0)
 511         return 0;
 512     return res & flag->default_val.i64;
 513 }
 514
 515 static void opt_list(void *obj, void *av_log_obj, const char *unit,
 516                      int req_flags, int rej_flags)
 517 {
 518     const AVOption *opt = NULL;
 519
 520     while ((opt = av_opt_next(obj, opt))) {
 521         if (!(opt->flags & req_flags) || (opt->flags & rej_flags))
 522             continue;
 523
 524         /* Don't print CONST's on level one.
 525          * Don't print anything but CONST's on level two.
 526          * Only print items from the requested unit.
 527          */
 528         if (!unit && opt->type == AV_OPT_TYPE_CONST)
 529             continue;
 530         else if (unit && opt->type != AV_OPT_TYPE_CONST)
 531             continue;
 532         else if (unit && opt->type == AV_OPT_TYPE_CONST && strcmp(unit, opt->unit))
 533             continue;
 534         else if (unit && opt->type == AV_OPT_TYPE_CONST)
 535             av_log(av_log_obj, AV_LOG_INFO, "   %-15s ", opt->name);
 536         else
 537             av_log(av_log_obj, AV_LOG_INFO, "-%-17s ", opt->name);
 538
 539         switch (opt->type) {
 540         case AV_OPT_TYPE_FLAGS:
 541             av_log(av_log_obj, AV_LOG_INFO, "%-7s ", "<flags>");
 542             break;
 543         case AV_OPT_TYPE_INT:
 544             av_log(av_log_obj, AV_LOG_INFO, "%-7s ", "<int>");
 545             break;
 546         case AV_OPT_TYPE_INT64:
 547             av_log(av_log_obj, AV_LOG_INFO, "%-7s ", "<int64>");
 548             break;
 549         case AV_OPT_TYPE_DOUBLE:
 550             av_log(av_log_obj, AV_LOG_INFO, "%-7s ", "<double>");
 551             break;
 552         case AV_OPT_TYPE_FLOAT:
 553             av_log(av_log_obj, AV_LOG_INFO, "%-7s ", "<float>");
 554             break;
 555         case AV_OPT_TYPE_STRING:
 556             av_log(av_log_obj, AV_LOG_INFO, "%-7s ", "<string>");
 557             break;
 558         case AV_OPT_TYPE_RATIONAL:
 559             av_log(av_log_obj, AV_LOG_INFO, "%-7s ", "<rational>");
 560             break;
 561         case AV_OPT_TYPE_BINARY:
 562             av_log(av_log_obj, AV_LOG_INFO, "%-7s ", "<binary>");
 563             break;
 564         case AV_OPT_TYPE_CONST:
 565         default:
 566             av_log(av_log_obj, AV_LOG_INFO, "%-7s ", "");
 567             break;
 568         }
 569         av_log(av_log_obj, AV_LOG_INFO, "%c", (opt->flags & AV_OPT_FLAG_ENCODING_PARAM) ? 'E' : '.');
 570         av_log(av_log_obj, AV_LOG_INFO, "%c", (opt->flags & AV_OPT_FLAG_DECODING_PARAM) ? 'D' : '.');
 571         av_log(av_log_obj, AV_LOG_INFO, "%c", (opt->flags & AV_OPT_FLAG_VIDEO_PARAM)    ? 'V' : '.');
 572         av_log(av_log_obj, AV_LOG_INFO, "%c", (opt->flags & AV_OPT_FLAG_AUDIO_PARAM)    ? 'A' : '.');
 573         av_log(av_log_obj, AV_LOG_INFO, "%c", (opt->flags & AV_OPT_FLAG_SUBTITLE_PARAM) ? 'S' : '.');
 574         av_log(av_log_obj, AV_LOG_INFO, "%c", (opt->flags & AV_OPT_FLAG_EXPORT)         ? 'X' : '.');
 575         av_log(av_log_obj, AV_LOG_INFO, "%c", (opt->flags & AV_OPT_FLAG_READONLY)       ? 'R' : '.');
 576
 577         if (opt->help)
 578             av_log(av_log_obj, AV_LOG_INFO, " %s", opt->help);
 579         av_log(av_log_obj, AV_LOG_INFO, "\n");
 580         if (opt->unit && opt->type != AV_OPT_TYPE_CONST)
 581             opt_list(obj, av_log_obj, opt->unit, req_flags, rej_flags);
 582     }
 583 }
 584
 585 int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags)
 586 {
 587     if (!obj)
 588         return -1;
 589
 590     av_log(av_log_obj, AV_LOG_INFO, "%s AVOptions:\n", (*(AVClass **)obj)->class_name);
 591
 592     opt_list(obj, av_log_obj, NULL, req_flags, rej_flags);
 593
 594     return 0;
 595 }
 596
 597 void av_opt_set_defaults(void *s)
 598 {
 599     const AVOption *opt = NULL;
 600     while ((opt = av_opt_next(s, opt))) {
 601         if (opt->flags & AV_OPT_FLAG_READONLY)
 602             continue;
 603
 604         switch (opt->type) {
 605         case AV_OPT_TYPE_CONST:
 606             /* Nothing to be done here */
 607             break;
 608         case AV_OPT_TYPE_FLAGS:
 609         case AV_OPT_TYPE_INT:
 610         case AV_OPT_TYPE_INT64:
 611             av_opt_set_int(s, opt->name, opt->default_val.i64, 0);
 612             break;
 613         case AV_OPT_TYPE_DOUBLE:
 614         case AV_OPT_TYPE_FLOAT:
 615         {
 616             double val;
 617             val = opt->default_val.dbl;
 618             av_opt_set_double(s, opt->name, val, 0);
 619         }
 620         break;
 621         case AV_OPT_TYPE_RATIONAL:
 622         {
 623             AVRational val;
 624             val = av_d2q(opt->default_val.dbl, INT_MAX);
 625             av_opt_set_q(s, opt->name, val, 0);
 626         }
 627         break;
 628         case AV_OPT_TYPE_STRING:
 629             av_opt_set(s, opt->name, opt->default_val.str, 0);
 630             break;
 631         case AV_OPT_TYPE_BINARY:
 632         case AV_OPT_TYPE_DICT:
 633             /* Cannot set defaults for these types */
 634             break;
 635         default:
 636             av_log(s, AV_LOG_DEBUG, "AVOption type %d of option %s not implemented yet\n",
 637                    opt->type, opt->name);
 638         }
 639     }
 640 }
 641
 642 /**
 643  * Store the value in the field in ctx that is named like key.
 644  * ctx must be an AVClass context, storing is done using AVOptions.
 645  *
 646  * @param buf the string to parse, buf will be updated to point at the
 647  * separator just after the parsed key/value pair
 648  * @param key_val_sep a 0-terminated list of characters used to
 649  * separate key from value
 650  * @param pairs_sep a 0-terminated list of characters used to separate
 651  * two pairs from each other
 652  * @return 0 if the key/value pair has been successfully parsed and
 653  * set, or a negative value corresponding to an AVERROR code in case
 654  * of error:
 655  * AVERROR(EINVAL) if the key/value pair cannot be parsed,
 656  * the error code issued by av_opt_set() if the key/value pair
 657  * cannot be set
 658  */
 659 static int parse_key_value_pair(void *ctx, const char **buf,
 660                                 const char *key_val_sep, const char *pairs_sep)
 661 {
 662     char *key = av_get_token(buf, key_val_sep);
 663     char *val;
 664     int ret;
 665
 666     if (!key)
 667         return AVERROR(ENOMEM);
 668
 669     if (*key && strspn(*buf, key_val_sep)) {
 670         (*buf)++;
 671         val = av_get_token(buf, pairs_sep);
 672         if (!val) {
 673             av_freep(&key);
 674             return AVERROR(ENOMEM);
 675         }
 676     } else {
 677         av_log(ctx, AV_LOG_ERROR, "Missing key or no key/value separator found after key '%s'\n", key);
 678         av_free(key);
 679         return AVERROR(EINVAL);
 680     }
 681
 682     av_log(ctx, AV_LOG_DEBUG, "Setting value '%s' for key '%s'\n", val, key);
 683
 684     ret = av_opt_set(ctx, key, val, AV_OPT_SEARCH_CHILDREN);
 685     if (ret == AVERROR_OPTION_NOT_FOUND)
 686         av_log(ctx, AV_LOG_ERROR, "Key '%s' not found.\n", key);
 687
 688     av_free(key);
 689     av_free(val);
 690     return ret;
 691 }
 692
 693 int av_set_options_string(void *ctx, const char *opts,
 694                           const char *key_val_sep, const char *pairs_sep)
 695 {
 696     int ret, count = 0;
 697
 698     if (!opts)
 699         return 0;
 700
 701     while (*opts) {
 702         if ((ret = parse_key_value_pair(ctx, &opts, key_val_sep, pairs_sep)) < 0)
 703             return ret;
 704         count++;
 705
 706         if (*opts)
 707             opts++;
 708     }
 709
 710     return count;
 711 }
 712
 713 void av_opt_free(void *obj)
 714 {
 715     const AVOption *o = NULL;
 716     while ((o = av_opt_next(obj, o))) {
 717         switch (o->type) {
 718         case AV_OPT_TYPE_STRING:
 719         case AV_OPT_TYPE_BINARY:
 720             av_freep((uint8_t *)obj + o->offset);
 721             break;
 722
 723         case AV_OPT_TYPE_DICT:
 724             av_dict_free((AVDictionary **)(((uint8_t *)obj) + o->offset));
 725             break;
 726
 727         default:
 728             break;
 729         }
 730     }
 731 }
 732
 733 int av_opt_set_dict(void *obj, AVDictionary **options)
 734 {
 735     AVDictionaryEntry *t = NULL;
 736     AVDictionary    *tmp = NULL;
 737     int ret = 0;
 738
 739     while ((t = av_dict_get(*options, "", t, AV_DICT_IGNORE_SUFFIX))) {
 740         ret = av_opt_set(obj, t->key, t->value, 0);
 741         if (ret == AVERROR_OPTION_NOT_FOUND)
 742             av_dict_set(&tmp, t->key, t->value, 0);
 743         else if (ret < 0) {
 744             av_log(obj, AV_LOG_ERROR, "Error setting option %s to value %s.\n", t->key, t->value);
 745             break;
 746         }
 747         ret = 0;
 748     }
 749     av_dict_free(options);
 750     *options = tmp;
 751     return ret;
 752 }
 753
 754 const AVOption *av_opt_find(void *obj, const char *name, const char *unit,
 755                             int opt_flags, int search_flags)
 756 {
 757     return av_opt_find2(obj, name, unit, opt_flags, search_flags, NULL);
 758 }
 759
 760 const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,
 761                              int opt_flags, int search_flags, void **target_obj)
 762 {
 763     const AVClass  *c = *(AVClass **)obj;
 764     const AVOption *o = NULL;
 765
 766     if (!c)
 767         return NULL;
 768
 769     if (search_flags & AV_OPT_SEARCH_CHILDREN) {
 770         if (search_flags & AV_OPT_SEARCH_FAKE_OBJ) {
 771             const AVClass *child = NULL;
 772             while (child = av_opt_child_class_next(c, child))
 773                 if (o = av_opt_find2(&child, name, unit, opt_flags, search_flags, NULL))
 774                     return o;
 775         } else {
 776             void *child = NULL;
 777             while (child = av_opt_child_next(obj, child))
 778                 if (o = av_opt_find2(child, name, unit, opt_flags, search_flags, target_obj))
 779                     return o;
 780         }
 781     }
 782
 783     while (o = av_opt_next(obj, o)) {
 784         if (!strcmp(o->name, name) && (o->flags & opt_flags) == opt_flags &&
 785             ((!unit && o->type != AV_OPT_TYPE_CONST) ||
 786               (unit && o->unit && !strcmp(o->unit, unit)))) {
 787             if (target_obj) {
 788                 if (!(search_flags & AV_OPT_SEARCH_FAKE_OBJ))
 789                     *target_obj = obj;
 790                 else
 791                     *target_obj = NULL;
 792             }
 793             return o;
 794         }
 795     }
 796     return NULL;
 797 }
 798
 799 void *av_opt_child_next(void *obj, void *prev)
 800 {
 801     const AVClass *c = *(AVClass **)obj;
 802     if (c->child_next)
 803         return c->child_next(obj, prev);
 804     return NULL;
 805 }
 806
 807 const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev)
 808 {
 809     if (parent->child_class_next)
 810         return parent->child_class_next(prev);
 811     return NULL;
 812 }
 813
 814 static int opt_size(enum AVOptionType type)
 815 {
 816     switch (type) {
 817     case AV_OPT_TYPE_INT:
 818     case AV_OPT_TYPE_FLAGS:
 819         return sizeof(int);
 820     case AV_OPT_TYPE_INT64:
 821         return sizeof(int64_t);
 822     case AV_OPT_TYPE_DOUBLE:
 823         return sizeof(double);
 824     case AV_OPT_TYPE_FLOAT:
 825         return sizeof(float);
 826     case AV_OPT_TYPE_STRING:
 827         return sizeof(uint8_t *);
 828     case AV_OPT_TYPE_RATIONAL:
 829         return sizeof(AVRational);
 830     case AV_OPT_TYPE_BINARY:
 831         return sizeof(uint8_t *) + sizeof(int);
 832     }
 833     return AVERROR(EINVAL);
 834 }
 835
 836 int av_opt_copy(void *dst, const void *src)
 837 {
 838     const AVOption *o = NULL;
 839     const AVClass *c;
 840     int ret = 0;
 841
 842     if (!src)
 843         return AVERROR(EINVAL);
 844
 845     c = *(AVClass **)src;
 846     if (!c || c != *(AVClass **)dst)
 847         return AVERROR(EINVAL);
 848
 849     while ((o = av_opt_next(src, o))) {
 850         void *field_dst = (uint8_t *)dst + o->offset;
 851         void *field_src = (uint8_t *)src + o->offset;
 852         uint8_t **field_dst8 = (uint8_t **)field_dst;
 853         uint8_t **field_src8 = (uint8_t **)field_src;
 854
 855         if (o->type == AV_OPT_TYPE_STRING) {
 856             set_string(dst, o, *field_src8, field_dst8);
 857             if (*field_src8 && !*field_dst8)
 858                 ret = AVERROR(ENOMEM);
 859         } else if (o->type == AV_OPT_TYPE_BINARY) {
 860             int len = *(int *)(field_src8 + 1);
 861             if (*field_dst8 != *field_src8)
 862                 av_freep(field_dst8);
 863             if (len) {
 864                 *field_dst8 = av_malloc(len);
 865                 if (!*field_dst8) {
 866                     ret = AVERROR(ENOMEM);
 867                     len = 0;
 868                 }
 869                 memcpy(*field_dst8, *field_src8, len);
 870             } else {
 871                 *field_dst8 = NULL;
 872             }
 873             *(int *)(field_dst8 + 1) = len;
 874         } else if (o->type == AV_OPT_TYPE_CONST) {
 875             // do nothing
 876         } else {
 877             int size = opt_size(o->type);
 878             if (size < 0)
 879                 ret = size;
 880             else
 881                 memcpy(field_dst, field_src, size);
 882         }
 883     }
 884     return ret;
 885 }