2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
4 * This file is part of FFmpeg.
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.
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.
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
22 * @file libavutil/common.h
23 * common internal and external API header
26 #ifndef AVUTIL_COMMON_H
27 #define AVUTIL_COMMON_H
39 # define AV_GCC_VERSION_AT_LEAST(x,y) (__GNUC__ > x || __GNUC__ == x && __GNUC_MINOR__ >= y)
41 # define AV_GCC_VERSION_AT_LEAST(x,y) 0
44 #ifndef av_always_inline
45 #if AV_GCC_VERSION_AT_LEAST(3,1)
46 # define av_always_inline __attribute__((always_inline)) inline
48 # define av_always_inline inline
53 #if AV_GCC_VERSION_AT_LEAST(3,1)
54 # define av_noinline __attribute__((noinline))
61 #if AV_GCC_VERSION_AT_LEAST(3,1)
62 # define av_pure __attribute__((pure))
69 #if AV_GCC_VERSION_AT_LEAST(2,6)
70 # define av_const __attribute__((const))
77 #if (!defined(__ICC) || __ICC > 1100) && AV_GCC_VERSION_AT_LEAST(4,3)
78 # define av_cold __attribute__((cold))
85 #if AV_GCC_VERSION_AT_LEAST(4,1)
86 # define av_flatten __attribute__((flatten))
92 #ifndef attribute_deprecated
93 #if AV_GCC_VERSION_AT_LEAST(3,1)
94 # define attribute_deprecated __attribute__((deprecated))
96 # define attribute_deprecated
101 #if defined(__GNUC__)
102 # define av_unused __attribute__((unused))
109 #if defined(__GNUC__) && !defined(__ICC)
110 # define av_uninit(x) x=x
112 # define av_uninit(x) x
116 //rounded division & shift
117 #define RSHIFT(a,b) ((a) > 0 ? ((a) + ((1<<(b))>>1))>>(b) : ((a) + ((1<<(b))>>1)-1)>>(b))
119 #define ROUNDED_DIV(a,b) (((a)>0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
120 #define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
121 #define FFSIGN(a) ((a) > 0 ? 1 : -1)
123 #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
124 #define FFMAX3(a,b,c) FFMAX(FFMAX(a,b),c)
125 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
126 #define FFMIN3(a,b,c) FFMIN(FFMIN(a,b),c)
128 #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)
129 #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
131 /* misc math functions */
132 extern const uint8_t ff_log2_tab
[256];
134 static inline av_const
int av_log2(unsigned int v
)
137 if (v
& 0xffff0000) {
150 static inline av_const
int av_log2_16bit(unsigned int v
)
163 * Clips a signed integer value into the amin-amax range.
164 * @param a value to clip
165 * @param amin minimum value of the clip range
166 * @param amax maximum value of the clip range
167 * @return clipped value
169 static inline av_const
int av_clip(int a
, int amin
, int amax
)
171 if (a
< amin
) return amin
;
172 else if (a
> amax
) return amax
;
177 * Clips a signed integer value into the 0-255 range.
178 * @param a value to clip
179 * @return clipped value
181 static inline av_const
uint8_t av_clip_uint8(int a
)
183 if (a
&(~255)) return (-a
)>>31;
188 * Clips a signed integer value into the -32768,32767 range.
189 * @param a value to clip
190 * @return clipped value
192 static inline av_const
int16_t av_clip_int16(int a
)
194 if ((a
+32768) & ~65535) return (a
>>31) ^ 32767;
199 * Clips a float value into the amin-amax range.
200 * @param a value to clip
201 * @param amin minimum value of the clip range
202 * @param amax maximum value of the clip range
203 * @return clipped value
205 static inline av_const
float av_clipf(float a
, float amin
, float amax
)
207 if (a
< amin
) return amin
;
208 else if (a
> amax
) return amax
;
212 #define MKTAG(a,b,c,d) (a | (b << 8) | (c << 16) | (d << 24))
213 #define MKBETAG(a,b,c,d) (d | (c << 8) | (b << 16) | (a << 24))
216 * \def GET_UTF8(val, GET_BYTE, ERROR)
217 * Converts a UTF-8 character (up to 4 bytes long) to its 32-bit UCS-4 encoded form
218 * \param val is the output and should be of type uint32_t. It holds the converted
219 * UCS-4 character and should be a left value.
220 * \param GET_BYTE gets UTF-8 encoded bytes from any proper source. It can be
221 * a function or a statement whose return value or evaluated value is of type
222 * uint8_t. It will be executed up to 4 times for values in the valid UTF-8 range,
223 * and up to 7 times in the general case.
224 * \param ERROR action that should be taken when an invalid UTF-8 byte is returned
225 * from GET_BYTE. It should be a statement that jumps out of the macro,
226 * like exit(), goto, return, break, or continue.
228 #define GET_UTF8(val, GET_BYTE, ERROR)\
231 int ones= 7 - av_log2(val ^ 255);\
236 int tmp= GET_BYTE - 128;\
239 val= (val<<6) + tmp;\
244 * \def PUT_UTF8(val, tmp, PUT_BYTE)
245 * Converts a 32-bit Unicode character to its UTF-8 encoded form (up to 4 bytes long).
246 * \param val is an input-only argument and should be of type uint32_t. It holds
247 * a UCS-4 encoded Unicode character that is to be converted to UTF-8. If
248 * val is given as a function it is executed only once.
249 * \param tmp is a temporary variable and should be of type uint8_t. It
250 * represents an intermediate value during conversion that is to be
251 * output by PUT_BYTE.
252 * \param PUT_BYTE writes the converted UTF-8 bytes to any proper destination.
253 * It could be a function or a statement, and uses tmp as the input byte.
254 * For example, PUT_BYTE could be "*output++ = tmp;" PUT_BYTE will be
255 * executed up to 4 times for values in the valid UTF-8 range and up to
256 * 7 times in the general case, depending on the length of the converted
259 #define PUT_UTF8(val, tmp, PUT_BYTE)\
267 bytes = (av_log2(in) + 4) / 5;\
268 shift = (bytes - 1) * 6;\
269 tmp = (256 - (256 >> bytes)) | (in >> shift);\
271 while (shift >= 6) {\
273 tmp = 0x80 | ((in >> shift) & 0x3f);\
281 //#ifdef HAVE_AV_CONFIG_H
282 //# include "ffmpeg_config.h"
283 # include "internal.h"
284 //#endif /* HAVE_AV_CONFIG_H */
286 #endif /* AVUTIL_COMMON_H */