include/vlc_common.h

   1 /*****************************************************************************
   2  * vlc_common.h: common definitions
   3  * Collection of useful common types and macros definitions
   4  *****************************************************************************
   5  * Copyright (C) 1998-2011 VLC authors and VideoLAN
   6  *
   7  * Authors: Samuel Hocevar <sam@via.ecp.fr>
   8  *          Vincent Seguin <seguin@via.ecp.fr>
   9  *          Gildas Bazin <gbazin@videolan.org>
  10  *          Rémi Denis-Courmont
  11  *
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms of the GNU Lesser General Public License as published by
  14  * the Free Software Foundation; either version 2.1 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  20  * GNU Lesser General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Lesser General Public License
  23  * along with this program; if not, write to the Free Software Foundation,
  24  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  25  *****************************************************************************/
  26
  27 #ifndef VLC_COMMON_H
  28 # define VLC_COMMON_H 1
  29
  30 /**
  31  * \defgroup vlc VLC plug-in programming interface
  32  * \file
  33  * \ingroup vlc
  34  * This file is a collection of common definitions and types
  35  */
  36
  37 /*****************************************************************************
  38  * Required vlc headers
  39  *****************************************************************************/
  40 #include "vlc_config.h"
  41
  42 /*****************************************************************************
  43  * Required system headers
  44  *****************************************************************************/
  45 #include <stdlib.h>
  46 #include <stdarg.h>
  47
  48 #include <string.h>
  49 #include <stdio.h>
  50 #include <inttypes.h>
  51 #include <stddef.h>
  52
  53 #ifndef __cplusplus
  54 # include <stdbool.h>
  55 #endif
  56
  57 /**
  58  * \defgroup cext C programming language extensions
  59  * \ingroup vlc
  60  *
  61  * This section defines a number of macros and inline functions extending the
  62  * C language. Most extensions are implemented by GCC and LLVM/Clang, and have
  63  * unoptimized fallbacks for other C11/C++11 conforming compilers.
  64  * @{
  65  */
  66 #ifdef __GNUC__
  67 # define VLC_GCC_VERSION(maj,min) \
  68     ((__GNUC__ > (maj)) || (__GNUC__ == (maj) && __GNUC_MINOR__ >= (min)))
  69 #else
  70 /** GCC version check */
  71 # define VLC_GCC_VERSION(maj,min) (0)
  72 #endif
  73
  74 /* Try to fix format strings for all versions of mingw and mingw64 */
  75 #if defined( _WIN32 ) && defined( __USE_MINGW_ANSI_STDIO )
  76  #undef PRId64
  77  #define PRId64 "lld"
  78  #undef PRIi64
  79  #define PRIi64 "lli"
  80  #undef PRIu64
  81  #define PRIu64 "llu"
  82  #undef PRIo64
  83  #define PRIo64 "llo"
  84  #undef PRIx64
  85  #define PRIx64 "llx"
  86  #define snprintf __mingw_snprintf
  87  #define vsnprintf __mingw_vsnprintf
  88  #define swprintf _snwprintf
  89 #endif
  90
  91 /* Function attributes for compiler warnings */
  92 #ifdef __GNUC__
  93 # define VLC_DEPRECATED __attribute__((deprecated))
  94 # if VLC_GCC_VERSION(6,0)
  95 #  define VLC_DEPRECATED_ENUM __attribute__((deprecated))
  96 # else
  97 #  define VLC_DEPRECATED_ENUM
  98 # endif
  99
 100 # if defined( _WIN32 ) && !defined( __clang__ )
 101 #  define VLC_FORMAT(x,y) __attribute__ ((format(gnu_printf,x,y)))
 102 # else
 103 #  define VLC_FORMAT(x,y) __attribute__ ((format(printf,x,y)))
 104 # endif
 105 # define VLC_FORMAT_ARG(x) __attribute__ ((format_arg(x)))
 106 # define VLC_MALLOC __attribute__ ((malloc))
 107 # define VLC_USED __attribute__ ((warn_unused_result))
 108
 109 #else
 110 /**
 111  * Deprecated functions or compound members annotation
 112  *
 113  * Use this macro in front of a function declaration or compound member
 114  * within a compound type declaration.
 115  * The compiler may emit a warning every time the function or member is used.
 116  *
 117  * Use \ref VLC_DEPRECATED_ENUM instead for enumeration members.
 118  */
 119 # define VLC_DEPRECATED
 120
 121 /**
 122  * Deprecated enum member annotation
 123  *
 124  * Use this macro after an enumerated type member declaration.
 125  * The compiler may emit a warning every time the enumeration member is used.
 126  *
 127  * See also \ref VLC_DEPRECATED.
 128  */
 129 # define VLC_DEPRECATED_ENUM
 130
 131 /**
 132  * String format function annotation
 133  *
 134  * Use this macro after a function prototype/declaration if the function
 135  * expects a standard C format string. This helps compiler diagnostics.
 136  *
 137  * @param x the position (starting from 1) of the format string argument
 138  * @param y the first position (also starting from 1) of the variable arguments
 139  *          following the format string (usually but not always \p x+1).
 140  */
 141 # define VLC_FORMAT(x,y)
 142
 143 /**
 144  * Format string translation function annotation
 145  *
 146  * Use this macro after a function prototype/declaration if the function
 147  * expects a format string as input and returns another format string as output
 148  * to another function.
 149  *
 150  * This is primarily intended for localization functions such as gettext().
 151  */
 152 # define VLC_FORMAT_ARG(x)
 153
 154 /**
 155  * Heap allocated result function annotation
 156  *
 157  * Use this macro to annotate a function that returns a pointer to memory that
 158  * cannot alias any other valid pointer.
 159  *
 160  * This is primarily used for functions that return a pointer to heap-allocated
 161  * memory, but it can be used for other applicable purposes.
 162  *
 163  * \warning Do not use this annotation if the returned pointer can in any way
 164  * alias a valid pointer at the time the function exits. This could lead to
 165  * very weird memory corruption bugs.
 166  */
 167 # define VLC_MALLOC
 168
 169 /**
 170  * Used result function annotation
 171  *
 172  * Use this macro to annotate a function whose result must be used.
 173  *
 174  * There are several cases where this is useful:
 175  * - If a function has no side effects (or no useful side effects), such that
 176  *   the only useful purpose of calling said function is to obtain its
 177  *   return value.
 178  * - If ignoring the function return value would lead to a resource leak
 179  *   (including but not limited to a memory leak).
 180  * - If a function cannot be used correctly without checking its return value.
 181  *   For instance, if the function can fail at any time.
 182  *
 183  * The compiler may warn if the return value of a function call is ignored.
 184  */
 185 # define VLC_USED
 186 #endif
 187
 188 #if defined (__ELF__) || defined (__MACH__)
 189 # define VLC_WEAK __attribute__((weak))
 190 #else
 191 /**
 192  * Weak symbol annotation
 193  *
 194  * Use this macro before an external identifier \b definition to mark it as a
 195  * weak symbol. A weak symbol can be overriden by another symbol of the same
 196  * name at the link time.
 197  */
 198 # define VLC_WEAK
 199 #endif
 200
 201 /* Branch prediction */
 202 #if defined (__GNUC__) || defined (__clang__)
 203 # define likely(p)     __builtin_expect(!!(p), 1)
 204 # define unlikely(p)   __builtin_expect(!!(p), 0)
 205 # define unreachable() __builtin_unreachable()
 206 #else
 207 /**
 208  * Predicted true condition
 209  *
 210  * This macro indicates that the condition is expected most often true.
 211  * The compiler may optimize the code assuming that this condition is usually
 212  * met.
 213  */
 214 # define likely(p)     (!!(p))
 215
 216 /**
 217  * Predicted false condition
 218  *
 219  * This macro indicates that the condition is expected most often false.
 220  * The compiler may optimize the code assuming that this condition is rarely
 221  * met.
 222  */
 223 # define unlikely(p)   (!!(p))
 224
 225 /**
 226  * Impossible branch
 227  *
 228  * This macro indicates that the branch cannot be reached at run-time, and
 229  * represents undefined behaviour.
 230  * The compiler may optimize the code assuming that the call flow will never
 231  * logically reach the point where this macro is expanded.
 232  *
 233  * See also \ref vlc_assert_unreachable.
 234  */
 235 # define unreachable() ((void)0)
 236 #endif
 237
 238 /**
 239  * Impossible branch assertion
 240  *
 241  * This macro asserts that the branch cannot be reached at run-time.
 242  *
 243  * If the branch is reached in a debug build, it will trigger an assertion
 244  * failure and abnormal program termination.
 245  *
 246  * If the branch is reached in a non-debug build, this macro is equivalent to
 247  * \ref unreachable and the behaviour is undefined.
 248  */
 249 #define vlc_assert_unreachable() (vlc_assert(!"unreachable"), unreachable())
 250
 251 /**
 252  * Run-time assertion
 253  *
 254  * This macro performs a run-time assertion if C assertions are enabled
 255  * and the following preprocessor symbol is defined:
 256  * @verbatim __LIBVLC__ @endverbatim
 257  * That restriction ensures that assertions in public header files are not
 258  * unwittingly <i>leaked</i> to externally-compiled plug-ins
 259  * including those header files.
 260  *
 261  * Within the LibVLC code base, this is exactly the same as assert(), which can
 262  * and probably should be used directly instead.
 263  */
 264 #ifdef __LIBVLC__
 265 # define vlc_assert(pred) assert(pred)
 266 #else
 267 # define vlc_assert(pred) ((void)0)
 268 #endif
 269
 270 /* Linkage */
 271 #ifdef __cplusplus
 272 # define VLC_EXTERN extern "C"
 273 #else
 274 # define VLC_EXTERN
 275 #endif
 276
 277 #if defined (_WIN32) && defined (DLL_EXPORT)
 278 # define VLC_EXPORT __declspec(dllexport)
 279 #elif defined (__GNUC__)
 280 # define VLC_EXPORT __attribute__((visibility("default")))
 281 #else
 282 # define VLC_EXPORT
 283 #endif
 284
 285 /**
 286  * Exported API call annotation
 287  *
 288  * This macro is placed before a function declaration to indicate that the
 289  * function is an API call of the LibVLC plugin API.
 290  */
 291 #define VLC_API VLC_EXTERN VLC_EXPORT
 292
 293 /** @} */
 294
 295 /*****************************************************************************
 296  * Basic types definitions
 297  *****************************************************************************/
 298 /**
 299  * The vlc_fourcc_t type.
 300  *
 301  * See http://www.webartz.com/fourcc/ for a very detailed list.
 302  */
 303 typedef uint32_t vlc_fourcc_t;
 304
 305 #ifdef WORDS_BIGENDIAN
 306 #   define VLC_FOURCC( a, b, c, d ) \
 307         ( ((uint32_t)d) | ( ((uint32_t)c) << 8 ) \
 308            | ( ((uint32_t)b) << 16 ) | ( ((uint32_t)a) << 24 ) )
 309 #   define VLC_TWOCC( a, b ) \
 310         ( (uint16_t)(b) | ( (uint16_t)(a) << 8 ) )
 311
 312 #else
 313 #   define VLC_FOURCC( a, b, c, d ) \
 314         ( ((uint32_t)a) | ( ((uint32_t)b) << 8 ) \
 315            | ( ((uint32_t)c) << 16 ) | ( ((uint32_t)d) << 24 ) )
 316 #   define VLC_TWOCC( a, b ) \
 317         ( (uint16_t)(a) | ( (uint16_t)(b) << 8 ) )
 318
 319 #endif
 320
 321 /**
 322  * Translate a vlc_fourcc into its string representation. This function
 323  * assumes there is enough room in psz_fourcc to store 4 characters in.
 324  *
 325  * \param fcc a vlc_fourcc_t
 326  * \param psz_fourcc string to store string representation of vlc_fourcc in
 327  */
 328 static inline void vlc_fourcc_to_char( vlc_fourcc_t fcc, char *psz_fourcc )
 329 {
 330     memcpy( psz_fourcc, &fcc, 4 );
 331 }
 332
 333 /*****************************************************************************
 334  * Classes declaration
 335  *****************************************************************************/
 336
 337 /* Internal types */
 338 typedef struct vlc_object_t vlc_object_t;
 339 typedef struct libvlc_int_t libvlc_int_t;
 340 typedef struct date_t date_t;
 341
 342 /* Playlist */
 343
 344 typedef struct playlist_t playlist_t;
 345 typedef struct playlist_item_t playlist_item_t;
 346 typedef struct services_discovery_t services_discovery_t;
 347 typedef struct vlc_renderer_discovery_t vlc_renderer_discovery_t;
 348 typedef struct vlc_renderer_item_t vlc_renderer_item_t;
 349
 350 /* Modules */
 351 typedef struct module_t module_t;
 352 typedef struct module_config_t module_config_t;
 353
 354 typedef struct config_category_t config_category_t;
 355
 356 /* Input */
 357 typedef struct input_thread_t input_thread_t;
 358 typedef struct input_item_t input_item_t;
 359 typedef struct input_item_node_t input_item_node_t;
 360 typedef struct stream_t     stream_t;
 361 typedef struct stream_t demux_t;
 362 typedef struct es_out_t     es_out_t;
 363 typedef struct es_out_id_t  es_out_id_t;
 364 typedef struct seekpoint_t seekpoint_t;
 365 typedef struct info_t info_t;
 366 typedef struct info_category_t info_category_t;
 367 typedef struct input_attachment_t input_attachment_t;
 368
 369 /* Format */
 370 typedef struct audio_format_t audio_format_t;
 371 typedef struct video_format_t video_format_t;
 372 typedef struct subs_format_t subs_format_t;
 373 typedef struct es_format_t es_format_t;
 374 typedef struct video_palette_t video_palette_t;
 375 typedef struct vlc_es_id_t vlc_es_id_t;
 376
 377 /* Audio */
 378 typedef struct audio_output audio_output_t;
 379 typedef audio_format_t audio_sample_format_t;
 380
 381 /* Video */
 382 typedef struct vout_thread_t vout_thread_t;
 383 typedef struct vlc_viewpoint_t vlc_viewpoint_t;
 384
 385 typedef video_format_t video_frame_format_t;
 386 typedef struct picture_t picture_t;
 387
 388 /* Subpictures */
 389 typedef struct spu_t spu_t;
 390 typedef struct subpicture_t subpicture_t;
 391 typedef struct subpicture_region_t subpicture_region_t;
 392
 393 typedef struct image_handler_t image_handler_t;
 394
 395 /* Stream output */
 396 typedef struct sout_instance_t sout_instance_t;
 397
 398 typedef struct sout_input_t sout_input_t;
 399 typedef struct sout_packetizer_input_t sout_packetizer_input_t;
 400
 401 typedef struct sout_access_out_t sout_access_out_t;
 402
 403 typedef struct sout_mux_t sout_mux_t;
 404
 405 typedef struct sout_stream_t    sout_stream_t;
 406
 407 typedef struct config_chain_t       config_chain_t;
 408 typedef struct session_descriptor_t session_descriptor_t;
 409
 410 /* Decoders */
 411 typedef struct decoder_t         decoder_t;
 412 typedef struct decoder_synchro_t decoder_synchro_t;
 413
 414 /* Encoders */
 415 typedef struct encoder_t      encoder_t;
 416
 417 /* Filters */
 418 typedef struct filter_t filter_t;
 419
 420 /* Network */
 421 typedef struct vlc_url_t vlc_url_t;
 422
 423 /* Misc */
 424 typedef struct iso639_lang_t iso639_lang_t;
 425
 426 /* block */
 427 typedef struct block_t      block_t;
 428 typedef struct block_fifo_t block_fifo_t;
 429
 430 /* Hashing */
 431 typedef struct md5_s md5_t;
 432
 433 /* XML */
 434 typedef struct xml_t xml_t;
 435 typedef struct xml_reader_t xml_reader_t;
 436
 437 /* vod server */
 438 typedef struct vod_t     vod_t;
 439 typedef struct vod_media_t vod_media_t;
 440
 441 /* VLM */
 442 typedef struct vlm_t         vlm_t;
 443 typedef struct vlm_message_t vlm_message_t;
 444
 445 /* misc */
 446 typedef struct vlc_meta_t    vlc_meta_t;
 447 typedef struct input_stats_t input_stats_t;
 448 typedef struct addon_entry_t addon_entry_t;
 449
 450 /* Update */
 451 typedef struct update_t update_t;
 452
 453 /**
 454  * VLC value structure
 455  */
 456 typedef union
 457 {
 458     int64_t         i_int;
 459     bool            b_bool;
 460     float           f_float;
 461     char *          psz_string;
 462     void *          p_address;
 463     struct { int32_t x; int32_t y; } coords;
 464
 465 } vlc_value_t;
 466
 467 /*****************************************************************************
 468  * Error values (shouldn't be exposed)
 469  *****************************************************************************/
 470 /** No error */
 471 #define VLC_SUCCESS        (-0)
 472 /** Unspecified error */
 473 #define VLC_EGENERIC       (-1)
 474 /** Not enough memory */
 475 #define VLC_ENOMEM         (-2)
 476 /** Timeout */
 477 #define VLC_ETIMEOUT       (-3)
 478 /** Module not found */
 479 #define VLC_ENOMOD         (-4)
 480 /** Object not found */
 481 #define VLC_ENOOBJ         (-5)
 482 /** Variable not found */
 483 #define VLC_ENOVAR         (-6)
 484 /** Bad variable value */
 485 #define VLC_EBADVAR        (-7)
 486 /** Item not found */
 487 #define VLC_ENOITEM        (-8)
 488
 489 /*****************************************************************************
 490  * Variable callbacks: called when the value is modified
 491  *****************************************************************************/
 492 typedef int ( * vlc_callback_t ) ( vlc_object_t *,      /* variable's object */
 493                                    char const *,            /* variable name */
 494                                    vlc_value_t,                 /* old value */
 495                                    vlc_value_t,                 /* new value */
 496                                    void * );                /* callback data */
 497
 498 /*****************************************************************************
 499  * List callbacks: called when elements are added/removed from the list
 500  *****************************************************************************/
 501 typedef int ( * vlc_list_callback_t ) ( vlc_object_t *,      /* variable's object */
 502                                         char const *,            /* variable name */
 503                                         int,                  /* VLC_VAR_* action */
 504                                         vlc_value_t *,      /* new/deleted value  */
 505                                         void *);                 /* callback data */
 506
 507 /*****************************************************************************
 508  * OS-specific headers and thread types
 509  *****************************************************************************/
 510 #if defined( _WIN32 )
 511 #   include <malloc.h>
 512 #   ifndef PATH_MAX
 513 #       define PATH_MAX MAX_PATH
 514 #   endif
 515 #   include <windows.h>
 516 #endif
 517
 518 #ifdef __APPLE__
 519 #include <sys/syslimits.h>
 520 #include <AvailabilityMacros.h>
 521 #endif
 522
 523 #ifdef __OS2__
 524 #   define OS2EMX_PLAIN_CHAR
 525 #   define INCL_BASE
 526 #   define INCL_PM
 527 #   include <os2safe.h>
 528 #   include <os2.h>
 529 #endif
 530
 531 #include "vlc_tick.h"
 532 #include "vlc_threads.h"
 533
 534 /**
 535  * \defgroup intops Integer operations
 536  * \ingroup cext
 537  *
 538  * Common integer functions.
 539  * @{
 540  */
 541 /* __MAX and __MIN: self explanatory */
 542 #ifndef __MAX
 543 #   define __MAX(a, b)   ( ((a) > (b)) ? (a) : (b) )
 544 #endif
 545 #ifndef __MIN
 546 #   define __MIN(a, b)   ( ((a) < (b)) ? (a) : (b) )
 547 #endif
 548
 549 /* clip v in [min, max] */
 550 #define VLC_CLIP(v, min, max)    __MIN(__MAX((v), (min)), (max))
 551
 552 /** Greatest common divisor */
 553 VLC_USED
 554 static inline int64_t GCD ( int64_t a, int64_t b )
 555 {
 556     while( b )
 557     {
 558         int64_t c = a % b;
 559         a = b;
 560         b = c;
 561     }
 562     return a;
 563 }
 564
 565 /* function imported from libavutil/common.h */
 566 VLC_USED
 567 static inline uint8_t clip_uint8_vlc( int32_t a )
 568 {
 569     if( a&(~255) ) return (-a)>>31;
 570     else           return a;
 571 }
 572
 573 /**
 574  * \defgroup bitops Bit operations
 575  * @{
 576  */
 577
 578 #define VLC_INT_FUNC(basename) \
 579         VLC_INT_FUNC_TYPE(basename, unsigned, ) \
 580         VLC_INT_FUNC_TYPE(basename, unsigned long, l) \
 581         VLC_INT_FUNC_TYPE(basename, unsigned long long, ll)
 582
 583 #if defined (__GNUC__) || defined (__clang__)
 584 # define VLC_INT_FUNC_TYPE(basename,type,suffix) \
 585 VLC_USED static inline int vlc_##basename##suffix(type x) \
 586 { \
 587     return __builtin_##basename##suffix(x); \
 588 }
 589
 590 VLC_INT_FUNC(clz)
 591 #else
 592 VLC_USED static inline int vlc_clzll(unsigned long long x)
 593 {
 594     int i = sizeof (x) * 8;
 595
 596     while (x)
 597     {
 598         x >>= 1;
 599         i--;
 600     }
 601     return i;
 602 }
 603
 604 VLC_USED static inline int vlc_clzl(unsigned long x)
 605 {
 606     return vlc_clzll(x) - ((sizeof (long long) - sizeof (long)) * 8);
 607 }
 608
 609 VLC_USED static inline int vlc_clz(unsigned x)
 610 {
 611     return vlc_clzll(x) - ((sizeof (long long) - sizeof (int)) * 8);
 612 }
 613
 614 VLC_USED static inline int vlc_ctz_generic(unsigned long long x)
 615 {
 616     unsigned i = sizeof (x) * 8;
 617
 618     while (x)
 619     {
 620         x <<= 1;
 621         i--;
 622     }
 623     return i;
 624 }
 625
 626 VLC_USED static inline int vlc_parity_generic(unsigned long long x)
 627 {
 628     for (unsigned i = 4 * sizeof (x); i > 0; i /= 2)
 629         x ^= x >> i;
 630     return x & 1;
 631 }
 632
 633 VLC_USED static inline int vlc_popcount_generic(unsigned long long x)
 634 {
 635     int count = 0;
 636     while (x)
 637     {
 638         count += x & 1;
 639         x = x >> 1;
 640     }
 641     return count;
 642 }
 643
 644 # define VLC_INT_FUNC_TYPE(basename,type,suffix) \
 645 VLC_USED static inline int vlc_##basename##suffix(type x) \
 646 { \
 647     return vlc_##basename##_generic(x); \
 648 }
 649 #endif
 650
 651 VLC_INT_FUNC(ctz)
 652 VLC_INT_FUNC(parity)
 653 VLC_INT_FUNC(popcount)
 654
 655 #ifndef __cplusplus
 656 # define VLC_INT_GENERIC(func,x) \
 657     _Generic((x), \
 658         unsigned char:      func(x), \
 659           signed char:      func(x), \
 660         unsigned short:     func(x), \
 661           signed short:     func(x), \
 662         unsigned int:       func(x), \
 663           signed int:       func(x), \
 664         unsigned long:      func##l(x), \
 665           signed long:      func##l(x), \
 666         unsigned long long: func##ll(x), \
 667           signed long long: func##ll(x))
 668
 669 /**
 670  * Count leading zeroes
 671  *
 672  * This function counts the number of consecutive zero (clear) bits
 673  * down from the highest order bit in an unsigned integer.
 674  *
 675  * \param x a non-zero integer
 676  * \note This macro assumes that CHAR_BIT equals 8.
 677  * \warning By definition, the result depends on the (width of the) type of x.
 678  * \return The number of leading zero bits in x.
 679  */
 680 # define clz(x) \
 681     _Generic((x), \
 682         unsigned char: (vlc_clz(x) - (sizeof (unsigned) - 1) * 8), \
 683         unsigned short: (vlc_clz(x) \
 684         - (sizeof (unsigned) - sizeof (unsigned short)) * 8), \
 685         unsigned: vlc_clz(x), \
 686         unsigned long: vlc_clzl(x), \
 687         unsigned long long: vlc_clzll(x))
 688
 689 /**
 690  * Count trailing zeroes
 691  *
 692  * This function counts the number of consecutive zero bits
 693  * up from the lowest order bit in an unsigned integer.
 694  *
 695  * \param x a non-zero integer
 696  * \note This function assumes that CHAR_BIT equals 8.
 697  * \return The number of trailing zero bits in x.
 698  */
 699 # define ctz(x) VLC_INT_GENERIC(vlc_ctz, x)
 700
 701 /**
 702  * Parity
 703  *
 704  * This function determines the parity of an integer.
 705  * \retval 0 if x has an even number of set bits.
 706  * \retval 1 if x has an odd number of set bits.
 707  */
 708 # define parity(x) VLC_INT_GENERIC(vlc_parity, x)
 709
 710 /**
 711  * Bit weight / population count
 712  *
 713  * This function counts the number of non-zero bits in an integer.
 714  *
 715  * \return The count of non-zero bits.
 716  */
 717 # define vlc_popcount(x) \
 718     _Generic((x), \
 719         signed char:  vlc_popcount((unsigned char)(x)), \
 720         signed short: vlc_popcount((unsigned short)(x)), \
 721         default: VLC_INT_GENERIC(vlc_popcount ,x))
 722 #else
 723 VLC_USED static inline int vlc_popcount(unsigned char x)
 724 {
 725     return vlc_popcount((unsigned)x);
 726 }
 727
 728 VLC_USED static inline int vlc_popcount(unsigned short x)
 729 {
 730     return vlc_popcount((unsigned)x);
 731 }
 732
 733 VLC_USED static inline int vlc_popcount(unsigned long x)
 734 {
 735     return vlc_popcountl(x);
 736 }
 737
 738 VLC_USED static inline int vlc_popcount(unsigned long long x)
 739 {
 740     return vlc_popcountll(x);
 741 }
 742 #endif
 743
 744 /** Byte swap (16 bits) */
 745 VLC_USED
 746 static inline uint16_t vlc_bswap16(uint16_t x)
 747 {
 748     return (x << 8) | (x >> 8);
 749 }
 750
 751 /** Byte swap (32 bits) */
 752 VLC_USED
 753 static inline uint32_t vlc_bswap32(uint32_t x)
 754 {
 755 #if defined (__GNUC__) || defined(__clang__)
 756     return __builtin_bswap32 (x);
 757 #else
 758     return ((x & 0x000000FF) << 24)
 759          | ((x & 0x0000FF00) <<  8)
 760          | ((x & 0x00FF0000) >>  8)
 761          | ((x & 0xFF000000) >> 24);
 762 #endif
 763 }
 764
 765 /** Byte swap (64 bits) */
 766 VLC_USED
 767 static inline uint64_t vlc_bswap64(uint64_t x)
 768 {
 769 #if defined (__GNUC__) || defined(__clang__)
 770     return __builtin_bswap64 (x);
 771 #elif !defined (__cplusplus)
 772     return ((x & 0x00000000000000FF) << 56)
 773          | ((x & 0x000000000000FF00) << 40)
 774          | ((x & 0x0000000000FF0000) << 24)
 775          | ((x & 0x00000000FF000000) <<  8)
 776          | ((x & 0x000000FF00000000) >>  8)
 777          | ((x & 0x0000FF0000000000) >> 24)
 778          | ((x & 0x00FF000000000000) >> 40)
 779          | ((x & 0xFF00000000000000) >> 56);
 780 #else
 781     return ((x & 0x00000000000000FFULL) << 56)
 782          | ((x & 0x000000000000FF00ULL) << 40)
 783          | ((x & 0x0000000000FF0000ULL) << 24)
 784          | ((x & 0x00000000FF000000ULL) <<  8)
 785          | ((x & 0x000000FF00000000ULL) >>  8)
 786          | ((x & 0x0000FF0000000000ULL) >> 24)
 787          | ((x & 0x00FF000000000000ULL) >> 40)
 788          | ((x & 0xFF00000000000000ULL) >> 56);
 789 #endif
 790 }
 791 /** @} */
 792
 793 /**
 794  * \defgroup overflow Overflowing arithmetic
 795  * @{
 796  */
 797 static inline bool uadd_overflow(unsigned a, unsigned b, unsigned *res)
 798 {
 799 #if VLC_GCC_VERSION(5,0) || defined(__clang__)
 800      return __builtin_uadd_overflow(a, b, res);
 801 #else
 802      *res = a + b;
 803      return (a + b) < a;
 804 #endif
 805 }
 806
 807 static inline bool uaddl_overflow(unsigned long a, unsigned long b,
 808                                   unsigned long *res)
 809 {
 810 #if VLC_GCC_VERSION(5,0) || defined(__clang__)
 811      return __builtin_uaddl_overflow(a, b, res);
 812 #else
 813      *res = a + b;
 814      return (a + b) < a;
 815 #endif
 816 }
 817
 818 static inline bool uaddll_overflow(unsigned long long a, unsigned long long b,
 819                                    unsigned long long *res)
 820 {
 821 #if VLC_GCC_VERSION(5,0) || defined(__clang__)
 822      return __builtin_uaddll_overflow(a, b, res);
 823 #else
 824      *res = a + b;
 825      return (a + b) < a;
 826 #endif
 827 }
 828
 829 #ifndef __cplusplus
 830 /**
 831  * Overflowing addition
 832  *
 833  * Converts \p a and \p b to the type of \p *r.
 834  * Then computes the sum of both conversions while checking for overflow.
 835  * Finally stores the result in \p *r.
 836  *
 837  * \param a an integer
 838  * \param b an integer
 839  * \param r a pointer to an integer [OUT]
 840  * \retval false The sum did not overflow.
 841  * \retval true The sum overflowed.
 842  */
 843 # define add_overflow(a,b,r) \
 844     _Generic(*(r), \
 845         unsigned: uadd_overflow(a, b, (unsigned *)(r)), \
 846         unsigned long: uaddl_overflow(a, b, (unsigned long *)(r)), \
 847         unsigned long long: uaddll_overflow(a, b, (unsigned long long *)(r)))
 848 #else
 849 static inline bool add_overflow(unsigned a, unsigned b, unsigned *res)
 850 {
 851     return uadd_overflow(a, b, res);
 852 }
 853
 854 static inline bool add_overflow(unsigned long a, unsigned long b,
 855                                 unsigned long *res)
 856 {
 857     return uaddl_overflow(a, b, res);
 858 }
 859
 860 static inline bool add_overflow(unsigned long long a, unsigned long long b,
 861                                 unsigned long long *res)
 862 {
 863     return uaddll_overflow(a, b, res);
 864 }
 865 #endif
 866
 867 #if !(VLC_GCC_VERSION(5,0) || defined(__clang__))
 868 # include <limits.h>
 869 #endif
 870
 871 static inline bool umul_overflow(unsigned a, unsigned b, unsigned *res)
 872 {
 873 #if VLC_GCC_VERSION(5,0) || defined(__clang__)
 874      return __builtin_umul_overflow(a, b, res);
 875 #else
 876      *res = a * b;
 877      return b > 0 && a > (UINT_MAX / b);
 878 #endif
 879 }
 880
 881 static inline bool umull_overflow(unsigned long a, unsigned long b,
 882                                   unsigned long *res)
 883 {
 884 #if VLC_GCC_VERSION(5,0) || defined(__clang__)
 885      return __builtin_umull_overflow(a, b, res);
 886 #else
 887      *res = a * b;
 888      return b > 0 && a > (ULONG_MAX / b);
 889 #endif
 890 }
 891
 892 static inline bool umulll_overflow(unsigned long long a, unsigned long long b,
 893                                    unsigned long long *res)
 894 {
 895 #if VLC_GCC_VERSION(5,0) || defined(__clang__)
 896      return __builtin_umulll_overflow(a, b, res);
 897 #else
 898      *res = a * b;
 899      return b > 0 && a > (ULLONG_MAX / b);
 900 #endif
 901 }
 902
 903 #ifndef __cplusplus
 904 /**
 905  * Overflowing multiplication
 906  *
 907  * Converts \p a and \p b to the type of \p *r.
 908  * Then computes the product of both conversions while checking for overflow.
 909  * Finally stores the result in \p *r.
 910  *
 911  * \param a an integer
 912  * \param b an integer
 913  * \param r a pointer to an integer [OUT]
 914  * \retval false The product did not overflow.
 915  * \retval true The product overflowed.
 916  */
 917 #define mul_overflow(a,b,r) \
 918     _Generic(*(r), \
 919         unsigned: umul_overflow(a, b, (unsigned *)(r)), \
 920         unsigned long: umull_overflow(a, b, (unsigned long *)(r)), \
 921         unsigned long long: umulll_overflow(a, b, (unsigned long long *)(r)))
 922 #else
 923 static inline bool mul_overflow(unsigned a, unsigned b, unsigned *res)
 924 {
 925     return umul_overflow(a, b, res);
 926 }
 927
 928 static inline bool mul_overflow(unsigned long a, unsigned long b,
 929                                 unsigned long *res)
 930 {
 931     return umull_overflow(a, b, res);
 932 }
 933
 934 static inline bool mul_overflow(unsigned long long a, unsigned long long b,
 935                                 unsigned long long *res)
 936 {
 937     return umulll_overflow(a, b, res);
 938 }
 939 #endif
 940 /** @} */
 941 /** @} */
 942
 943 /* Free and set set the variable to NULL */
 944 #define FREENULL(a) do { free( a ); a = NULL; } while(0)
 945
 946 #define EMPTY_STR(str) (!str || !*str)
 947
 948 VLC_API char const * vlc_error( int ) VLC_USED;
 949
 950 #include <vlc_arrays.h>
 951
 952 /* MSB (big endian)/LSB (little endian) conversions - network order is always
 953  * MSB, and should be used for both network communications and files. */
 954
 955 #ifdef WORDS_BIGENDIAN
 956 # define hton16(i) ((uint16_t)(i))
 957 # define hton32(i) ((uint32_t)(i))
 958 # define hton64(i) ((uint64_t)(i))
 959 #else
 960 # define hton16(i) vlc_bswap16(i)
 961 # define hton32(i) vlc_bswap32(i)
 962 # define hton64(i) vlc_bswap64(i)
 963 #endif
 964 #define ntoh16(i) hton16(i)
 965 #define ntoh32(i) hton32(i)
 966 #define ntoh64(i) hton64(i)
 967
 968 /** Reads 16 bits in network byte order */
 969 VLC_USED
 970 static inline uint16_t U16_AT (const void *p)
 971 {
 972     uint16_t x;
 973
 974     memcpy (&x, p, sizeof (x));
 975     return ntoh16 (x);
 976 }
 977
 978 /** Reads 32 bits in network byte order */
 979 VLC_USED
 980 static inline uint32_t U32_AT (const void *p)
 981 {
 982     uint32_t x;
 983
 984     memcpy (&x, p, sizeof (x));
 985     return ntoh32 (x);
 986 }
 987
 988 /** Reads 64 bits in network byte order */
 989 VLC_USED
 990 static inline uint64_t U64_AT (const void *p)
 991 {
 992     uint64_t x;
 993
 994     memcpy (&x, p, sizeof (x));
 995     return ntoh64 (x);
 996 }
 997
 998 #define GetWBE(p)  U16_AT(p)
 999 #define GetDWBE(p) U32_AT(p)
1000 #define GetQWBE(p) U64_AT(p)
1001
1002 /** Reads 16 bits in little-endian order */
1003 VLC_USED
1004 static inline uint16_t GetWLE (const void *p)
1005 {
1006     uint16_t x;
1007
1008     memcpy (&x, p, sizeof (x));
1009 #ifdef WORDS_BIGENDIAN
1010     x = vlc_bswap16 (x);
1011 #endif
1012     return x;
1013 }
1014
1015 /** Reads 32 bits in little-endian order */
1016 VLC_USED
1017 static inline uint32_t GetDWLE (const void *p)
1018 {
1019     uint32_t x;
1020
1021     memcpy (&x, p, sizeof (x));
1022 #ifdef WORDS_BIGENDIAN
1023     x = vlc_bswap32 (x);
1024 #endif
1025     return x;
1026 }
1027
1028 /** Reads 64 bits in little-endian order */
1029 VLC_USED
1030 static inline uint64_t GetQWLE (const void *p)
1031 {
1032     uint64_t x;
1033
1034     memcpy (&x, p, sizeof (x));
1035 #ifdef WORDS_BIGENDIAN
1036     x = vlc_bswap64 (x);
1037 #endif
1038     return x;
1039 }
1040
1041 /** Writes 16 bits in network byte order */
1042 static inline void SetWBE (void *p, uint16_t w)
1043 {
1044     w = hton16 (w);
1045     memcpy (p, &w, sizeof (w));
1046 }
1047
1048 /** Writes 32 bits in network byte order */
1049 static inline void SetDWBE (void *p, uint32_t dw)
1050 {
1051     dw = hton32 (dw);
1052     memcpy (p, &dw, sizeof (dw));
1053 }
1054
1055 /** Writes 64 bits in network byte order */
1056 static inline void SetQWBE (void *p, uint64_t qw)
1057 {
1058     qw = hton64 (qw);
1059     memcpy (p, &qw, sizeof (qw));
1060 }
1061
1062 /** Writes 16 bits in little endian order */
1063 static inline void SetWLE (void *p, uint16_t w)
1064 {
1065 #ifdef WORDS_BIGENDIAN
1066     w = vlc_bswap16 (w);
1067 #endif
1068     memcpy (p, &w, sizeof (w));
1069 }
1070
1071 /** Writes 32 bits in little endian order */
1072 static inline void SetDWLE (void *p, uint32_t dw)
1073 {
1074 #ifdef WORDS_BIGENDIAN
1075     dw = vlc_bswap32 (dw);
1076 #endif
1077     memcpy (p, &dw, sizeof (dw));
1078 }
1079
1080 /** Writes 64 bits in little endian order */
1081 static inline void SetQWLE (void *p, uint64_t qw)
1082 {
1083 #ifdef WORDS_BIGENDIAN
1084     qw = vlc_bswap64 (qw);
1085 #endif
1086     memcpy (p, &qw, sizeof (qw));
1087 }
1088
1089 /* */
1090 #define VLC_UNUSED(x) (void)(x)
1091
1092 /* Stuff defined in src/extras/libc.c */
1093
1094 #if defined(_WIN32)
1095 /* several type definitions */
1096 #   if defined( __MINGW32__ )
1097 #       if !defined( _OFF_T_ )
1098             typedef long long _off_t;
1099             typedef _off_t off_t;
1100 #           define _OFF_T_
1101 #       else
1102 #           ifdef off_t
1103 #               undef off_t
1104 #           endif
1105 #           define off_t long long
1106 #       endif
1107 #   endif
1108
1109 #   ifndef O_NONBLOCK
1110 #       define O_NONBLOCK 0
1111 #   endif
1112
1113 #   include <tchar.h>
1114 #endif /* _WIN32 */
1115
1116 typedef struct {
1117     unsigned num, den;
1118 } vlc_rational_t;
1119
1120 VLC_API bool vlc_ureduce( unsigned *, unsigned *, uint64_t, uint64_t, uint64_t );
1121
1122 #define container_of(ptr, type, member) \
1123     ((type *)(((char *)(ptr)) - offsetof(type, member)))
1124
1125 VLC_USED VLC_MALLOC
1126 static inline void *vlc_alloc(size_t count, size_t size)
1127 {
1128     return mul_overflow(count, size, &size) ? NULL : malloc(size);
1129 }
1130
1131 VLC_USED
1132 static inline void *vlc_reallocarray(void *ptr, size_t count, size_t size)
1133 {
1134     return mul_overflow(count, size, &size) ? NULL : realloc(ptr, size);
1135 }
1136
1137 /*****************************************************************************
1138  * I18n stuff
1139  *****************************************************************************/
1140 VLC_API const char *vlc_gettext(const char *msgid) VLC_FORMAT_ARG(1);
1141 VLC_API const char *vlc_ngettext(const char *s, const char *p, unsigned long n)
1142 VLC_FORMAT_ARG(1) VLC_FORMAT_ARG(2);
1143
1144 #define vlc_pgettext( ctx, id ) \
1145         vlc_pgettext_aux( ctx "\004" id, id )
1146
1147 VLC_FORMAT_ARG(2)
1148 static inline const char *vlc_pgettext_aux( const char *ctx, const char *id )
1149 {
1150     const char *tr = vlc_gettext( ctx );
1151     return (tr == ctx) ? id : tr;
1152 }
1153
1154 /*****************************************************************************
1155  * Loosy memory allocation functions. Do not use in new code.
1156  *****************************************************************************/
1157 static inline void *xmalloc(size_t len)
1158 {
1159     void *ptr = malloc(len);
1160     if (unlikely(ptr == NULL && len > 0))
1161         abort();
1162     return ptr;
1163 }
1164
1165 static inline void *xrealloc(void *ptr, size_t len)
1166 {
1167     void *nptr = realloc(ptr, len);
1168     if (unlikely(nptr == NULL && len > 0))
1169         abort();
1170     return nptr;
1171 }
1172
1173 static inline char *xstrdup (const char *str)
1174 {
1175     char *ptr = strdup (str);
1176     if (unlikely(ptr == NULL))
1177         abort ();
1178     return ptr;
1179 }
1180
1181 /*****************************************************************************
1182  * libvlc features
1183  *****************************************************************************/
1184 VLC_API const char * VLC_CompileBy( void ) VLC_USED;
1185 VLC_API const char * VLC_CompileHost( void ) VLC_USED;
1186 VLC_API const char * VLC_Compiler( void ) VLC_USED;
1187
1188 /*****************************************************************************
1189  * Additional vlc stuff
1190  *****************************************************************************/
1191 #include "vlc_messages.h"
1192 #include "vlc_objects.h"
1193 #include "vlc_variables.h"
1194 #include "vlc_configuration.h"
1195
1196 #if defined( _WIN32 ) || defined( __OS2__ )
1197 #   define DIR_SEP_CHAR '\\'
1198 #   define DIR_SEP "\\"
1199 #   define PATH_SEP_CHAR ';'
1200 #   define PATH_SEP ";"
1201 #else
1202 #   define DIR_SEP_CHAR '/'
1203 #   define DIR_SEP "/"
1204 #   define PATH_SEP_CHAR ':'
1205 #   define PATH_SEP ":"
1206 #endif
1207
1208 #define LICENSE_MSG \
1209   _("This program comes with NO WARRANTY, to the extent permitted by " \
1210     "law.\nYou may redistribute it under the terms of the GNU General " \
1211     "Public License;\nsee the file named COPYING for details.\n" \
1212     "Written by the VideoLAN team; see the AUTHORS file.\n")
1213
1214 #endif /* !VLC_COMMON_H */