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
37 #include "attributes.h"
39 #ifdef HAVE_AV_CONFIG_H
43 #ifdef HAVE_AV_CONFIG_H
47 //rounded division & shift
48 #define RSHIFT(a,b) ((a) > 0 ? ((a) + ((1<<(b))>>1))>>(b) : ((a) + ((1<<(b))>>1)-1)>>(b))
50 #define ROUNDED_DIV(a,b) (((a)>0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
51 #define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
52 #define FFSIGN(a) ((a) > 0 ? 1 : -1)
54 #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
55 #define FFMAX3(a,b,c) FFMAX(FFMAX(a,b),c)
56 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
57 #define FFMIN3(a,b,c) FFMIN(FFMIN(a,b),c)
59 #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)
60 #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
61 #define FFALIGN(x, a) (((x)+(a)-1)&~((a)-1))
63 /* misc math functions */
64 extern const uint8_t ff_log2_tab[256];
66 extern const uint8_t av_reverse[256];
69 static inline av_const int av_log2(unsigned int v)
87 static inline av_const int av_log2_16bit(unsigned int v)
101 * Clips a signed integer value into the amin-amax range.
102 * @param a value to clip
103 * @param amin minimum value of the clip range
104 * @param amax maximum value of the clip range
105 * @return clipped value
107 static inline av_const int av_clip(int a, int amin, int amax)
109 if (a < amin) return amin;
110 else if (a > amax) return amax;
115 * Clips a signed integer value into the 0-255 range.
116 * @param a value to clip
117 * @return clipped value
119 static inline av_const uint8_t av_clip_uint8(int a)
121 if (a&(~255)) return (-a)>>31;
126 * Clips a signed integer value into the 0-65535 range.
127 * @param a value to clip
128 * @return clipped value
130 static inline av_const uint16_t av_clip_uint16(int a)
132 if (a&(~65535)) return (-a)>>31;
137 * Clips a signed integer value into the -32768,32767 range.
138 * @param a value to clip
139 * @return clipped value
141 static inline av_const int16_t av_clip_int16(int a)
143 if ((a+32768) & ~65535) return (a>>31) ^ 32767;
148 * Clips a float value into the amin-amax range.
149 * @param a value to clip
150 * @param amin minimum value of the clip range
151 * @param amax maximum value of the clip range
152 * @return clipped value
154 static inline av_const float av_clipf(float a, float amin, float amax)
156 if (a < amin) return amin;
157 else if (a > amax) return amax;
161 /** Computes ceil(log2(x)).
162 * @param x value used to compute ceil(log2(x))
163 * @return computed ceiling of log2(x)
165 static inline av_const int av_ceil_log2(int x)
167 return av_log2((x - 1) << 1);
170 #define MKTAG(a,b,c,d) (a | (b << 8) | (c << 16) | (d << 24))
171 #define MKBETAG(a,b,c,d) (d | (c << 8) | (b << 16) | (a << 24))
174 * \def GET_UTF8(val, GET_BYTE, ERROR)
175 * Converts a UTF-8 character (up to 4 bytes long) to its 32-bit UCS-4 encoded form
176 * \param val is the output and should be of type uint32_t. It holds the converted
177 * UCS-4 character and should be a left value.
178 * \param GET_BYTE gets UTF-8 encoded bytes from any proper source. It can be
179 * a function or a statement whose return value or evaluated value is of type
180 * uint8_t. It will be executed up to 4 times for values in the valid UTF-8 range,
181 * and up to 7 times in the general case.
182 * \param ERROR action that should be taken when an invalid UTF-8 byte is returned
183 * from GET_BYTE. It should be a statement that jumps out of the macro,
184 * like exit(), goto, return, break, or continue.
186 #define GET_UTF8(val, GET_BYTE, ERROR)\
189 int ones= 7 - av_log2(val ^ 255);\
194 int tmp= GET_BYTE - 128;\
197 val= (val<<6) + tmp;\
202 * \def GET_UTF16(val, GET_16BIT, ERROR)
203 * Converts a UTF-16 character (2 or 4 bytes) to its 32-bit UCS-4 encoded form
204 * \param val is the output and should be of type uint32_t. It holds the converted
205 * UCS-4 character and should be a left value.
206 * \param GET_16BIT gets two bytes of UTF-16 encoded data converted to native endianness.
207 * It can be a function or a statement whose return value or evaluated value is of type
208 * uint16_t. It will be executed up to 2 times.
209 * \param ERROR action that should be taken when an invalid UTF-16 surrogate is
210 * returned from GET_BYTE. It should be a statement that jumps out of the macro,
211 * like exit(), goto, return, break, or continue.
213 #define GET_UTF16(val, GET_16BIT, ERROR)\
216 unsigned int hi = val - 0xD800;\
218 val = GET_16BIT - 0xDC00;\
219 if (val > 0x3FFU || hi > 0x3FFU)\
221 val += (hi<<10) + 0x10000;\
226 * \def PUT_UTF8(val, tmp, PUT_BYTE)
227 * Converts a 32-bit Unicode character to its UTF-8 encoded form (up to 4 bytes long).
228 * \param val is an input-only argument and should be of type uint32_t. It holds
229 * a UCS-4 encoded Unicode character that is to be converted to UTF-8. If
230 * val is given as a function it is executed only once.
231 * \param tmp is a temporary variable and should be of type uint8_t. It
232 * represents an intermediate value during conversion that is to be
233 * output by PUT_BYTE.
234 * \param PUT_BYTE writes the converted UTF-8 bytes to any proper destination.
235 * It could be a function or a statement, and uses tmp as the input byte.
236 * For example, PUT_BYTE could be "*output++ = tmp;" PUT_BYTE will be
237 * executed up to 4 times for values in the valid UTF-8 range and up to
238 * 7 times in the general case, depending on the length of the converted
241 #define PUT_UTF8(val, tmp, PUT_BYTE)\
249 bytes = (av_log2(in) + 4) / 5;\
250 shift = (bytes - 1) * 6;\
251 tmp = (256 - (256 >> bytes)) | (in >> shift);\
253 while (shift >= 6) {\
255 tmp = 0x80 | ((in >> shift) & 0x3f);\
262 * \def PUT_UTF16(val, tmp, PUT_16BIT)
263 * Converts a 32-bit Unicode character to its UTF-16 encoded form (2 or 4 bytes).
264 * \param val is an input-only argument and should be of type uint32_t. It holds
265 * a UCS-4 encoded Unicode character that is to be converted to UTF-16. If
266 * val is given as a function it is executed only once.
267 * \param tmp is a temporary variable and should be of type uint16_t. It
268 * represents an intermediate value during conversion that is to be
269 * output by PUT_16BIT.
270 * \param PUT_16BIT writes the converted UTF-16 data to any proper destination
271 * in desired endianness. It could be a function or a statement, and uses tmp
272 * as the input byte. For example, PUT_BYTE could be "*output++ = tmp;"
273 * PUT_BYTE will be executed 1 or 2 times depending on input character.
275 #define PUT_UTF16(val, tmp, PUT_16BIT)\
282 tmp = 0xD800 | ((in - 0x10000) >> 10);\
284 tmp = 0xDC00 | ((in - 0x10000) & 0x3FF);\
293 #ifdef HAVE_AV_CONFIG_H
294 # include "internal.h"
295 #endif /* HAVE_AV_CONFIG_H */
297 #endif /* AVUTIL_COMMON_H */