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common.h
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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
23  * common internal and external API header
24  */
25 
26 #ifndef AVUTIL_COMMON_H
27 #define AVUTIL_COMMON_H
28 
29 #if defined(__cplusplus) && !defined(__STDC_CONSTANT_MACROS) && !defined(UINT64_C)
30 #error missing -D__STDC_CONSTANT_MACROS / #define __STDC_CONSTANT_MACROS
31 #endif
32 
33 #include <errno.h>
34 #include <inttypes.h>
35 #include <limits.h>
36 #include <math.h>
37 #include <stdint.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <string.h>
41 
42 #include "attributes.h"
43 #include "version.h"
44 #include "libavutil/avconfig.h"
45 
46 #if AV_HAVE_BIGENDIAN
47 # define AV_NE(be, le) (be)
48 #else
49 # define AV_NE(be, le) (le)
50 #endif
51 
52 //rounded division & shift
53 #define RSHIFT(a,b) ((a) > 0 ? ((a) + ((1<<(b))>>1))>>(b) : ((a) + ((1<<(b))>>1)-1)>>(b))
54 /* assume b>0 */
55 #define ROUNDED_DIV(a,b) (((a)>0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
56 /* assume a>0 and b>0 */
57 #define FF_CEIL_RSHIFT(a,b) (!av_builtin_constant_p(b) ? -((-(a)) >> (b)) \
58  : ((a) + (1<<(b)) - 1) >> (b))
59 #define FFUDIV(a,b) (((a)>0 ?(a):(a)-(b)+1) / (b))
60 #define FFUMOD(a,b) ((a)-(b)*FFUDIV(a,b))
61 
62 /**
63  * Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they
64  * are not representable as absolute values of their type. This is the same
65  * as with *abs()
66  * @see FFNABS()
67  */
68 #define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
69 #define FFSIGN(a) ((a) > 0 ? 1 : -1)
70 
71 /**
72  * Negative Absolute value.
73  * this works for all integers of all types.
74  * As with many macros, this evaluates its argument twice, it thus must not have
75  * a sideeffect, that is FFNABS(x++) has undefined behavior.
76  */
77 #define FFNABS(a) ((a) <= 0 ? (a) : (-(a)))
78 
79 #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
80 #define FFMAX3(a,b,c) FFMAX(FFMAX(a,b),c)
81 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
82 #define FFMIN3(a,b,c) FFMIN(FFMIN(a,b),c)
83 
84 #define FFSWAP(type,a,b) do{type SWAP_tmp= b; b= a; a= SWAP_tmp;}while(0)
85 #define FF_ARRAY_ELEMS(a) (sizeof(a) / sizeof((a)[0]))
86 #define FFALIGN(x, a) (((x)+(a)-1)&~((a)-1))
87 
88 /* misc math functions */
89 
90 /**
91  * Reverse the order of the bits of an 8-bits unsigned integer.
92  */
93 #if FF_API_AV_REVERSE
94 extern attribute_deprecated const uint8_t av_reverse[256];
95 #endif
96 
97 #ifdef HAVE_AV_CONFIG_H
98 # include "config.h"
99 # include "intmath.h"
100 #endif
101 
102 /* Pull in unguarded fallback defines at the end of this file. */
103 #include "common.h"
104 
105 #ifndef av_log2
106 av_const int av_log2(unsigned v);
107 #endif
108 
109 #ifndef av_log2_16bit
110 av_const int av_log2_16bit(unsigned v);
111 #endif
112 
113 /**
114  * Clip a signed integer value into the amin-amax range.
115  * @param a value to clip
116  * @param amin minimum value of the clip range
117  * @param amax maximum value of the clip range
118  * @return clipped value
119  */
120 static av_always_inline av_const int av_clip_c(int a, int amin, int amax)
121 {
122 #if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
123  if (amin > amax) abort();
124 #endif
125  if (a < amin) return amin;
126  else if (a > amax) return amax;
127  else return a;
128 }
129 
130 /**
131  * Clip a signed 64bit integer value into the amin-amax range.
132  * @param a value to clip
133  * @param amin minimum value of the clip range
134  * @param amax maximum value of the clip range
135  * @return clipped value
136  */
137 static av_always_inline av_const int64_t av_clip64_c(int64_t a, int64_t amin, int64_t amax)
138 {
139 #if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
140  if (amin > amax) abort();
141 #endif
142  if (a < amin) return amin;
143  else if (a > amax) return amax;
144  else return a;
145 }
146 
147 /**
148  * Clip a signed integer value into the 0-255 range.
149  * @param a value to clip
150  * @return clipped value
151  */
153 {
154  if (a&(~0xFF)) return (-a)>>31;
155  else return a;
156 }
157 
158 /**
159  * Clip a signed integer value into the -128,127 range.
160  * @param a value to clip
161  * @return clipped value
162  */
164 {
165  if ((a+0x80U) & ~0xFF) return (a>>31) ^ 0x7F;
166  else return a;
167 }
168 
169 /**
170  * Clip a signed integer value into the 0-65535 range.
171  * @param a value to clip
172  * @return clipped value
173  */
175 {
176  if (a&(~0xFFFF)) return (-a)>>31;
177  else return a;
178 }
179 
180 /**
181  * Clip a signed integer value into the -32768,32767 range.
182  * @param a value to clip
183  * @return clipped value
184  */
186 {
187  if ((a+0x8000U) & ~0xFFFF) return (a>>31) ^ 0x7FFF;
188  else return a;
189 }
190 
191 /**
192  * Clip a signed 64-bit integer value into the -2147483648,2147483647 range.
193  * @param a value to clip
194  * @return clipped value
195  */
197 {
198  if ((a+0x80000000u) & ~UINT64_C(0xFFFFFFFF)) return (int32_t)((a>>63) ^ 0x7FFFFFFF);
199  else return (int32_t)a;
200 }
201 
202 /**
203  * Clip a signed integer into the -(2^p),(2^p-1) range.
204  * @param a value to clip
205  * @param p bit position to clip at
206  * @return clipped value
207  */
209 {
210  if ((a + (1 << p)) & ~((2 << p) - 1))
211  return (a >> 31) ^ ((1 << p) - 1);
212  else
213  return a;
214 }
215 
216 /**
217  * Clip a signed integer to an unsigned power of two range.
218  * @param a value to clip
219  * @param p bit position to clip at
220  * @return clipped value
221  */
222 static av_always_inline av_const unsigned av_clip_uintp2_c(int a, int p)
223 {
224  if (a & ~((1<<p) - 1)) return -a >> 31 & ((1<<p) - 1);
225  else return a;
226 }
227 
228 /**
229  * Add two signed 32-bit values with saturation.
230  *
231  * @param a one value
232  * @param b another value
233  * @return sum with signed saturation
234  */
235 static av_always_inline int av_sat_add32_c(int a, int b)
236 {
237  return av_clipl_int32((int64_t)a + b);
238 }
239 
240 /**
241  * Add a doubled value to another value with saturation at both stages.
242  *
243  * @param a first value
244  * @param b value doubled and added to a
245  * @return sum with signed saturation
246  */
247 static av_always_inline int av_sat_dadd32_c(int a, int b)
248 {
249  return av_sat_add32(a, av_sat_add32(b, b));
250 }
251 
252 /**
253  * Clip a float value into the amin-amax range.
254  * @param a value to clip
255  * @param amin minimum value of the clip range
256  * @param amax maximum value of the clip range
257  * @return clipped value
258  */
259 static av_always_inline av_const float av_clipf_c(float a, float amin, float amax)
260 {
261 #if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
262  if (amin > amax) abort();
263 #endif
264  if (a < amin) return amin;
265  else if (a > amax) return amax;
266  else return a;
267 }
268 
269 /**
270  * Clip a double value into the amin-amax range.
271  * @param a value to clip
272  * @param amin minimum value of the clip range
273  * @param amax maximum value of the clip range
274  * @return clipped value
275  */
276 static av_always_inline av_const double av_clipd_c(double a, double amin, double amax)
277 {
278 #if defined(HAVE_AV_CONFIG_H) && defined(ASSERT_LEVEL) && ASSERT_LEVEL >= 2
279  if (amin > amax) abort();
280 #endif
281  if (a < amin) return amin;
282  else if (a > amax) return amax;
283  else return a;
284 }
285 
286 /** Compute ceil(log2(x)).
287  * @param x value used to compute ceil(log2(x))
288  * @return computed ceiling of log2(x)
289  */
291 {
292  return av_log2((x - 1) << 1);
293 }
294 
295 /**
296  * Count number of bits set to one in x
297  * @param x value to count bits of
298  * @return the number of bits set to one in x
299  */
301 {
302  x -= (x >> 1) & 0x55555555;
303  x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
304  x = (x + (x >> 4)) & 0x0F0F0F0F;
305  x += x >> 8;
306  return (x + (x >> 16)) & 0x3F;
307 }
308 
309 /**
310  * Count number of bits set to one in x
311  * @param x value to count bits of
312  * @return the number of bits set to one in x
313  */
315 {
316  return av_popcount((uint32_t)x) + av_popcount((uint32_t)(x >> 32));
317 }
318 
319 #define MKTAG(a,b,c,d) ((a) | ((b) << 8) | ((c) << 16) | ((unsigned)(d) << 24))
320 #define MKBETAG(a,b,c,d) ((d) | ((c) << 8) | ((b) << 16) | ((unsigned)(a) << 24))
321 
322 /**
323  * Convert a UTF-8 character (up to 4 bytes) to its 32-bit UCS-4 encoded form.
324  *
325  * @param val Output value, must be an lvalue of type uint32_t.
326  * @param GET_BYTE Expression reading one byte from the input.
327  * Evaluated up to 7 times (4 for the currently
328  * assigned Unicode range). With a memory buffer
329  * input, this could be *ptr++.
330  * @param ERROR Expression to be evaluated on invalid input,
331  * typically a goto statement.
332  *
333  * @warning ERROR should not contain a loop control statement which
334  * could interact with the internal while loop, and should force an
335  * exit from the macro code (e.g. through a goto or a return) in order
336  * to prevent undefined results.
337  */
338 #define GET_UTF8(val, GET_BYTE, ERROR)\
339  val= GET_BYTE;\
340  {\
341  uint32_t top = (val & 128) >> 1;\
342  if ((val & 0xc0) == 0x80 || val >= 0xFE)\
343  ERROR\
344  while (val & top) {\
345  int tmp= GET_BYTE - 128;\
346  if(tmp>>6)\
347  ERROR\
348  val= (val<<6) + tmp;\
349  top <<= 5;\
350  }\
351  val &= (top << 1) - 1;\
352  }
353 
354 /**
355  * Convert a UTF-16 character (2 or 4 bytes) to its 32-bit UCS-4 encoded form.
356  *
357  * @param val Output value, must be an lvalue of type uint32_t.
358  * @param GET_16BIT Expression returning two bytes of UTF-16 data converted
359  * to native byte order. Evaluated one or two times.
360  * @param ERROR Expression to be evaluated on invalid input,
361  * typically a goto statement.
362  */
363 #define GET_UTF16(val, GET_16BIT, ERROR)\
364  val = GET_16BIT;\
365  {\
366  unsigned int hi = val - 0xD800;\
367  if (hi < 0x800) {\
368  val = GET_16BIT - 0xDC00;\
369  if (val > 0x3FFU || hi > 0x3FFU)\
370  ERROR\
371  val += (hi<<10) + 0x10000;\
372  }\
373  }\
374 
375 /**
376  * @def PUT_UTF8(val, tmp, PUT_BYTE)
377  * Convert a 32-bit Unicode character to its UTF-8 encoded form (up to 4 bytes long).
378  * @param val is an input-only argument and should be of type uint32_t. It holds
379  * a UCS-4 encoded Unicode character that is to be converted to UTF-8. If
380  * val is given as a function it is executed only once.
381  * @param tmp is a temporary variable and should be of type uint8_t. It
382  * represents an intermediate value during conversion that is to be
383  * output by PUT_BYTE.
384  * @param PUT_BYTE writes the converted UTF-8 bytes to any proper destination.
385  * It could be a function or a statement, and uses tmp as the input byte.
386  * For example, PUT_BYTE could be "*output++ = tmp;" PUT_BYTE will be
387  * executed up to 4 times for values in the valid UTF-8 range and up to
388  * 7 times in the general case, depending on the length of the converted
389  * Unicode character.
390  */
391 #define PUT_UTF8(val, tmp, PUT_BYTE)\
392  {\
393  int bytes, shift;\
394  uint32_t in = val;\
395  if (in < 0x80) {\
396  tmp = in;\
397  PUT_BYTE\
398  } else {\
399  bytes = (av_log2(in) + 4) / 5;\
400  shift = (bytes - 1) * 6;\
401  tmp = (256 - (256 >> bytes)) | (in >> shift);\
402  PUT_BYTE\
403  while (shift >= 6) {\
404  shift -= 6;\
405  tmp = 0x80 | ((in >> shift) & 0x3f);\
406  PUT_BYTE\
407  }\
408  }\
409  }
410 
411 /**
412  * @def PUT_UTF16(val, tmp, PUT_16BIT)
413  * Convert a 32-bit Unicode character to its UTF-16 encoded form (2 or 4 bytes).
414  * @param val is an input-only argument and should be of type uint32_t. It holds
415  * a UCS-4 encoded Unicode character that is to be converted to UTF-16. If
416  * val is given as a function it is executed only once.
417  * @param tmp is a temporary variable and should be of type uint16_t. It
418  * represents an intermediate value during conversion that is to be
419  * output by PUT_16BIT.
420  * @param PUT_16BIT writes the converted UTF-16 data to any proper destination
421  * in desired endianness. It could be a function or a statement, and uses tmp
422  * as the input byte. For example, PUT_BYTE could be "*output++ = tmp;"
423  * PUT_BYTE will be executed 1 or 2 times depending on input character.
424  */
425 #define PUT_UTF16(val, tmp, PUT_16BIT)\
426  {\
427  uint32_t in = val;\
428  if (in < 0x10000) {\
429  tmp = in;\
430  PUT_16BIT\
431  } else {\
432  tmp = 0xD800 | ((in - 0x10000) >> 10);\
433  PUT_16BIT\
434  tmp = 0xDC00 | ((in - 0x10000) & 0x3FF);\
435  PUT_16BIT\
436  }\
437  }\
438 
439 
440 
441 #include "mem.h"
442 
443 #ifdef HAVE_AV_CONFIG_H
444 # include "internal.h"
445 #endif /* HAVE_AV_CONFIG_H */
446 
447 #endif /* AVUTIL_COMMON_H */
448 
449 /*
450  * The following definitions are outside the multiple inclusion guard
451  * to ensure they are immediately available in intmath.h.
452  */
453 
454 #ifndef av_ceil_log2
455 # define av_ceil_log2 av_ceil_log2_c
456 #endif
457 #ifndef av_clip
458 # define av_clip av_clip_c
459 #endif
460 #ifndef av_clip64
461 # define av_clip64 av_clip64_c
462 #endif
463 #ifndef av_clip_uint8
464 # define av_clip_uint8 av_clip_uint8_c
465 #endif
466 #ifndef av_clip_int8
467 # define av_clip_int8 av_clip_int8_c
468 #endif
469 #ifndef av_clip_uint16
470 # define av_clip_uint16 av_clip_uint16_c
471 #endif
472 #ifndef av_clip_int16
473 # define av_clip_int16 av_clip_int16_c
474 #endif
475 #ifndef av_clipl_int32
476 # define av_clipl_int32 av_clipl_int32_c
477 #endif
478 #ifndef av_clip_intp2
479 # define av_clip_intp2 av_clip_intp2_c
480 #endif
481 #ifndef av_clip_uintp2
482 # define av_clip_uintp2 av_clip_uintp2_c
483 #endif
484 #ifndef av_sat_add32
485 # define av_sat_add32 av_sat_add32_c
486 #endif
487 #ifndef av_sat_dadd32
488 # define av_sat_dadd32 av_sat_dadd32_c
489 #endif
490 #ifndef av_clipf
491 # define av_clipf av_clipf_c
492 #endif
493 #ifndef av_clipd
494 # define av_clipd av_clipd_c
495 #endif
496 #ifndef av_popcount
497 # define av_popcount av_popcount_c
498 #endif
499 #ifndef av_popcount64
500 # define av_popcount64 av_popcount64_c
501 #endif