libavutil/common.h

   1 /*
   2  * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file libavutil/common.h
  23  * common internal and external API header
  24  */
  25
  26 #ifndef AVUTIL_COMMON_H
  27 #define AVUTIL_COMMON_H
  28
  29 #include <ctype.h>
  30 #include <errno.h>
  31 #include <inttypes.h>
  32 #include <limits.h>
  33 #include <math.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37
  38 #ifdef HAVE_AV_CONFIG_H
  39 #include "config.h"
  40 #endif
  41
  42 #ifdef __GNUC__
  43 #    define AV_GCC_VERSION_AT_LEAST(x,y) (__GNUC__ > x || __GNUC__ == x && __GNUC_MINOR__ >= y)
  44 #else
  45 #    define AV_GCC_VERSION_AT_LEAST(x,y) 0
  46 #endif
  47
  48 #ifndef av_always_inline
  49 #if AV_GCC_VERSION_AT_LEAST(3,1)
  50 #    define av_always_inline __attribute__((always_inline)) inline
  51 #else
  52 #    define av_always_inline inline
  53 #endif
  54 #endif
  55
  56 #ifndef av_noinline
  57 #if AV_GCC_VERSION_AT_LEAST(3,1)
  58 #    define av_noinline __attribute__((noinline))
  59 #else
  60 #    define av_noinline
  61 #endif
  62 #endif
  63
  64 #ifndef av_pure
  65 #if AV_GCC_VERSION_AT_LEAST(3,1)
  66 #    define av_pure __attribute__((pure))
  67 #else
  68 #    define av_pure
  69 #endif
  70 #endif
  71
  72 #ifndef av_const
  73 #if AV_GCC_VERSION_AT_LEAST(2,6)
  74 #    define av_const __attribute__((const))
  75 #else
  76 #    define av_const
  77 #endif
  78 #endif
  79
  80 #ifndef av_cold
  81 #if (!defined(__ICC) || __ICC > 1110) && AV_GCC_VERSION_AT_LEAST(4,3)
  82 #    define av_cold __attribute__((cold))
  83 #else
  84 #    define av_cold
  85 #endif
  86 #endif
  87
  88 #ifndef av_flatten
  89 #if (!defined(__ICC) || __ICC > 1110) && AV_GCC_VERSION_AT_LEAST(4,1)
  90 #    define av_flatten __attribute__((flatten))
  91 #else
  92 #    define av_flatten
  93 #endif
  94 #endif
  95
  96 #ifndef attribute_deprecated
  97 #if AV_GCC_VERSION_AT_LEAST(3,1)
  98 #    define attribute_deprecated __attribute__((deprecated))
  99 #else
 100 #    define attribute_deprecated
 101 #endif
 102 #endif
 103
 104 #ifndef av_unused
 105 #if defined(__GNUC__)
 106 #    define av_unused __attribute__((unused))
 107 #else
 108 #    define av_unused
 109 #endif
 110 #endif
 111
 112 #ifndef av_uninit
 113 #if defined(__GNUC__) && !defined(__ICC)
 114 #    define av_uninit(x) x=x
 115 #else
 116 #    define av_uninit(x) x
 117 #endif
 118 #endif
 119
 120 //rounded division & shift
 121 #define RSHIFT(a,b) ((a) > 0 ? ((a) + ((1<<(b))>>1))>>(b) : ((a) + ((1<<(b))>>1)-1)>>(b))
 122 /* assume b>0 */
 123 #define ROUNDED_DIV(a,b) (((a)>0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
 124 #define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
 125 #define FFSIGN(a) ((a) > 0 ? 1 : -1)
 126
 127 #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
 128 #define FFMAX3(a,b,c) FFMAX(FFMAX(a,b),c)
 129 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
 130 #define FFMIN3(a,b,c) FFMIN(FFMIN(a,b),c)
 131
 132 #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)
 133 #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
 134 #define FFALIGN(x, a) (((x)+(a)-1)&~((a)-1))
 135
 136 /* misc math functions */
 137 extern const uint8_t ff_log2_tab[256];
 138
 139 static inline av_const int av_log2(unsigned int v)
 140 {
 141     int n = 0;
 142     if (v & 0xffff0000) {
 143         v >>= 16;
 144         n += 16;
 145     }
 146     if (v & 0xff00) {
 147         v >>= 8;
 148         n += 8;
 149     }
 150     n += ff_log2_tab[v];
 151
 152     return n;
 153 }
 154
 155 static inline av_const int av_log2_16bit(unsigned int v)
 156 {
 157     int n = 0;
 158     if (v & 0xff00) {
 159         v >>= 8;
 160         n += 8;
 161     }
 162     n += ff_log2_tab[v];
 163
 164     return n;
 165 }
 166
 167 /**
 168  * Clips a signed integer value into the amin-amax range.
 169  * @param a value to clip
 170  * @param amin minimum value of the clip range
 171  * @param amax maximum value of the clip range
 172  * @return clipped value
 173  */
 174 static inline av_const int av_clip(int a, int amin, int amax)
 175 {
 176     if      (a < amin) return amin;
 177     else if (a > amax) return amax;
 178     else               return a;
 179 }
 180
 181 /**
 182  * Clips a signed integer value into the 0-255 range.
 183  * @param a value to clip
 184  * @return clipped value
 185  */
 186 static inline av_const uint8_t av_clip_uint8(int a)
 187 {
 188     if (a&(~255)) return (-a)>>31;
 189     else          return a;
 190 }
 191
 192 /**
 193  * Clips a signed integer value into the 0-65535 range.
 194  * @param a value to clip
 195  * @return clipped value
 196  */
 197 static inline av_const uint16_t av_clip_uint16(int a)
 198 {
 199     if (a&(~65535)) return (-a)>>31;
 200     else            return a;
 201 }
 202
 203 /**
 204  * Clips a signed integer value into the -32768,32767 range.
 205  * @param a value to clip
 206  * @return clipped value
 207  */
 208 static inline av_const int16_t av_clip_int16(int a)
 209 {
 210     if ((a+32768) & ~65535) return (a>>31) ^ 32767;
 211     else                    return a;
 212 }
 213
 214 /**
 215  * Clips a float value into the amin-amax range.
 216  * @param a value to clip
 217  * @param amin minimum value of the clip range
 218  * @param amax maximum value of the clip range
 219  * @return clipped value
 220  */
 221 static inline av_const float av_clipf(float a, float amin, float amax)
 222 {
 223     if      (a < amin) return amin;
 224     else if (a > amax) return amax;
 225     else               return a;
 226 }
 227
 228 /** Computes ceil(log2(x)).
 229  * @param x value used to compute ceil(log2(x))
 230  * @return computed ceiling of log2(x)
 231  */
 232 static inline av_const int av_ceil_log2(int x)
 233 {
 234     return av_log2((x - 1) << 1);
 235 }
 236
 237 #define MKTAG(a,b,c,d) (a | (b << 8) | (c << 16) | (d << 24))
 238 #define MKBETAG(a,b,c,d) (d | (c << 8) | (b << 16) | (a << 24))
 239
 240 /*!
 241  * \def GET_UTF8(val, GET_BYTE, ERROR)
 242  * Converts a UTF-8 character (up to 4 bytes long) to its 32-bit UCS-4 encoded form
 243  * \param val is the output and should be of type uint32_t. It holds the converted
 244  * UCS-4 character and should be a left value.
 245  * \param GET_BYTE gets UTF-8 encoded bytes from any proper source. It can be
 246  * a function or a statement whose return value or evaluated value is of type
 247  * uint8_t. It will be executed up to 4 times for values in the valid UTF-8 range,
 248  * and up to 7 times in the general case.
 249  * \param ERROR action that should be taken when an invalid UTF-8 byte is returned
 250  * from GET_BYTE. It should be a statement that jumps out of the macro,
 251  * like exit(), goto, return, break, or continue.
 252  */
 253 #define GET_UTF8(val, GET_BYTE, ERROR)\
 254     val= GET_BYTE;\
 255     {\
 256         int ones= 7 - av_log2(val ^ 255);\
 257         if(ones==1)\
 258             ERROR\
 259         val&= 127>>ones;\
 260         while(--ones > 0){\
 261             int tmp= GET_BYTE - 128;\
 262             if(tmp>>6)\
 263                 ERROR\
 264             val= (val<<6) + tmp;\
 265         }\
 266     }
 267
 268 /*!
 269  * \def PUT_UTF8(val, tmp, PUT_BYTE)
 270  * Converts a 32-bit Unicode character to its UTF-8 encoded form (up to 4 bytes long).
 271  * \param val is an input-only argument and should be of type uint32_t. It holds
 272  * a UCS-4 encoded Unicode character that is to be converted to UTF-8. If
 273  * val is given as a function it is executed only once.
 274  * \param tmp is a temporary variable and should be of type uint8_t. It
 275  * represents an intermediate value during conversion that is to be
 276  * output by PUT_BYTE.
 277  * \param PUT_BYTE writes the converted UTF-8 bytes to any proper destination.
 278  * It could be a function or a statement, and uses tmp as the input byte.
 279  * For example, PUT_BYTE could be "*output++ = tmp;" PUT_BYTE will be
 280  * executed up to 4 times for values in the valid UTF-8 range and up to
 281  * 7 times in the general case, depending on the length of the converted
 282  * Unicode character.
 283  */
 284 #define PUT_UTF8(val, tmp, PUT_BYTE)\
 285     {\
 286         int bytes, shift;\
 287         uint32_t in = val;\
 288         if (in < 0x80) {\
 289             tmp = in;\
 290             PUT_BYTE\
 291         } else {\
 292             bytes = (av_log2(in) + 4) / 5;\
 293             shift = (bytes - 1) * 6;\
 294             tmp = (256 - (256 >> bytes)) | (in >> shift);\
 295             PUT_BYTE\
 296             while (shift >= 6) {\
 297                 shift -= 6;\
 298                 tmp = 0x80 | ((in >> shift) & 0x3f);\
 299                 PUT_BYTE\
 300             }\
 301         }\
 302     }
 303
 304 #include "mem.h"
 305
 306 #ifdef HAVE_AV_CONFIG_H
 307 #    include "internal.h"
 308 #endif /* HAVE_AV_CONFIG_H */
 309
 310 #endif /* AVUTIL_COMMON_H */