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Comparing libecb/ecb.h (file contents):
Revision 1.1 by root, Thu May 26 16:41:12 2011 UTC vs.
Revision 1.95 by root, Tue May 29 21:06:01 2012 UTC

1/* 1/*
2 * libecb 2 * libecb - http://software.schmorp.de/pkg/libecb
3 * 3 *
4 * Copyright (c) 2011 Marc Alexander Lehmann 4 * Copyright (©) 2009-2012 Marc Alexander Lehmann <libecb@schmorp.de>
5 * Copyright (©) 2011 Emanuele Giaquinta
5 * All rights reserved. 6 * All rights reserved.
6 * 7 *
7 * Redistribution and use in source and binary forms, with or without modifica- 8 * Redistribution and use in source and binary forms, with or without modifica-
8 * tion, are permitted provided that the following conditions are met: 9 * tion, are permitted provided that the following conditions are met:
9 * 10 *
… …
27 */ 28 */
28 29
29#ifndef ECB_H 30#ifndef ECB_H
30#define ECB_H 31#define ECB_H
31 32
33/* 16 bits major, 16 bits minor */
34#define ECB_VERSION 0x00010001
35
36#ifdef _WIN32
37 typedef signed char int8_t;
38 typedef unsigned char uint8_t;
39 typedef signed short int16_t;
40 typedef unsigned short uint16_t;
41 typedef signed int int32_t;
42 typedef unsigned int uint32_t;
43 #if __GNUC__
44 typedef signed long long int64_t;
45 typedef unsigned long long uint64_t;
46 #else /* _MSC_VER || __BORLANDC__ */
47 typedef signed __int64 int64_t;
48 typedef unsigned __int64 uint64_t;
49 #endif
50 #ifdef _WIN64
51 #define ECB_PTRSIZE 8
52 typedef uint64_t uintptr_t;
53 typedef int64_t intptr_t;
54 #else
55 #define ECB_PTRSIZE 4
56 typedef uint32_t uintptr_t;
57 typedef int32_t intptr_t;
58 #endif
59 typedef intptr_t ptrdiff_t;
60#else
61 #include <inttypes.h>
62 #if UINTMAX_MAX > 0xffffffffU
63 #define ECB_PTRSIZE 8
64 #else
65 #define ECB_PTRSIZE 4
66 #endif
67#endif
68
69/* many compilers define _GNUC_ to some versions but then only implement
70 * what their idiot authors think are the "more important" extensions,
71 * causing enormous grief in return for some better fake benchmark numbers.
72 * or so.
73 * we try to detect these and simply assume they are not gcc - if they have
74 * an issue with that they should have done it right in the first place.
75 */
76#ifndef ECB_GCC_VERSION
77 #if !defined __GNUC_MINOR__ || defined __INTEL_COMPILER || defined __SUNPRO_C || defined __SUNPRO_CC || defined __llvm__ || defined __clang__
78 #define ECB_GCC_VERSION(major,minor) 0
79 #else
32#define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor))) 80 #define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
81 #endif
82#endif
83
84#define ECB_C (__STDC__+0) /* this assumes that __STDC__ is either empty or a number */
85#define ECB_C99 (__STDC_VERSION__ >= 199901L)
86#define ECB_C11 (__STDC_VERSION__ >= 201112L)
87#define ECB_CPP (__cplusplus+0)
88#define ECB_CPP98 (__cplusplus >= 199711L)
89#define ECB_CPP11 (__cplusplus >= 201103L)
90
91/*****************************************************************************/
92
93/* ECB_NO_THREADS - ecb is not used by multiple threads, ever */
94/* ECB_NO_SMP - ecb might be used in multiple threads, but only on a single cpu */
95
96#if ECB_NO_THREADS
97 #define ECB_NO_SMP 1
98#endif
99
100#if ECB_NO_SMP
101 #define ECB_MEMORY_FENCE do { } while (0)
102#endif
103
104#ifndef ECB_MEMORY_FENCE
105 #if ECB_GCC_VERSION(2,5) || defined __INTEL_COMPILER || (__llvm__ && __GNUC__) || __SUNPRO_C >= 0x5110 || __SUNPRO_CC >= 0x5110
106 #if __i386 || __i386__
107 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("lock; orb $0, -1(%%esp)" : : : "memory")
108 #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("" : : : "memory")
109 #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("")
110 #elif __amd64 || __amd64__ || __x86_64 || __x86_64__
111 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mfence" : : : "memory")
112 #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("" : : : "memory")
113 #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("")
114 #elif __powerpc__ || __ppc__ || __powerpc64__ || __ppc64__
115 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("sync" : : : "memory")
116 #elif defined __ARM_ARCH_6__ || defined __ARM_ARCH_6J__ \
117 || defined __ARM_ARCH_6K__ || defined __ARM_ARCH_6ZK__
118 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mcr p15,0,%0,c7,c10,5" : : "r" (0) : "memory")
119 #elif defined __ARM_ARCH_7__ || defined __ARM_ARCH_7A__ \
120 || defined __ARM_ARCH_7M__ || defined __ARM_ARCH_7R__
121 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("dmb" : : : "memory")
122 #elif __sparc || __sparc__
123 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("membar #LoadStore | #LoadLoad | #StoreStore | #StoreLoad" : : : "memory")
124 #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("membar #LoadStore | #LoadLoad" : : : "memory")
125 #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("membar #LoadStore | #StoreStore")
126 #elif defined __s390__ || defined __s390x__
127 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("bcr 15,0" : : : "memory")
128 #elif defined __mips__
129 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("sync" : : : "memory")
130 #elif defined __alpha__
131 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mb" : : : "memory")
132 #elif defined __hppa__
133 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("" : : : "memory")
134 #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("")
135 #elif defined __ia64__
136 #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mf" : : : "memory")
137 #endif
138 #endif
139#endif
140
141#ifndef ECB_MEMORY_FENCE
142 #if ECB_GCC_VERSION(4,7)
143 /* see comment below about the C11 memory model. in short - avoid */
144 #define ECB_MEMORY_FENCE __atomic_thread_fence (__ATOMIC_SEQ_CST)
145 #elif defined __clang && __has_feature (cxx_atomic)
146 /* see above */
147 #define ECB_MEMORY_FENCE __c11_atomic_thread_fence (__ATOMIC_SEQ_CST)
148 #elif ECB_GCC_VERSION(4,4) || defined __INTEL_COMPILER || defined __clang__
149 #define ECB_MEMORY_FENCE __sync_synchronize ()
150 #elif _MSC_VER >= 1400 /* VC++ 2005 */
151 #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier)
152 #define ECB_MEMORY_FENCE _ReadWriteBarrier ()
153 #define ECB_MEMORY_FENCE_ACQUIRE _ReadWriteBarrier () /* according to msdn, _ReadBarrier is not a load fence */
154 #define ECB_MEMORY_FENCE_RELEASE _WriteBarrier ()
155 #elif defined _WIN32
156 #include <WinNT.h>
157 #define ECB_MEMORY_FENCE MemoryBarrier () /* actually just xchg on x86... scary */
158 #elif __SUNPRO_C >= 0x5110 || __SUNPRO_CC >= 0x5110
159 #include <mbarrier.h>
160 #define ECB_MEMORY_FENCE __machine_rw_barrier ()
161 #define ECB_MEMORY_FENCE_ACQUIRE __machine_r_barrier ()
162 #define ECB_MEMORY_FENCE_RELEASE __machine_w_barrier ()
163 #elif __xlC__
164 #define ECB_MEMORY_FENCE __sync ()
165 #endif
166#endif
167
168#ifndef ECB_MEMORY_FENCE
169 #if ECB_C11 && !defined __STDC_NO_ATOMICS__
170 /* we assume that these memory fences work on all variables/all memory accesses, */
171 /* not just C11 atomics and atomic accesses */
172 #include <stdatomic.h>
173 /* unfortunately, the C11 memory model seems to be very limited, and unable to express */
174 /* simple barrier semantics. That means we need to take out thor's hammer. */
175 #define ECB_MEMORY_FENCE atomic_thread_fence (memory_order_seq_cst)
176 #endif
177#endif
178
179#ifndef ECB_MEMORY_FENCE
180 #if !ECB_AVOID_PTHREADS
181 /*
182 * if you get undefined symbol references to pthread_mutex_lock,
183 * or failure to find pthread.h, then you should implement
184 * the ECB_MEMORY_FENCE operations for your cpu/compiler
185 * OR provide pthread.h and link against the posix thread library
186 * of your system.
187 */
188 #include <pthread.h>
189 #define ECB_NEEDS_PTHREADS 1
190 #define ECB_MEMORY_FENCE_NEEDS_PTHREADS 1
191
192 static pthread_mutex_t ecb_mf_lock = PTHREAD_MUTEX_INITIALIZER;
193 #define ECB_MEMORY_FENCE do { pthread_mutex_lock (&ecb_mf_lock); pthread_mutex_unlock (&ecb_mf_lock); } while (0)
194 #endif
195#endif
196
197#if !defined ECB_MEMORY_FENCE_ACQUIRE && defined ECB_MEMORY_FENCE
198 #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
199#endif
200
201#if !defined ECB_MEMORY_FENCE_RELEASE && defined ECB_MEMORY_FENCE
202 #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
203#endif
204
205/*****************************************************************************/
206
207#if __cplusplus
208 #define ecb_inline static inline
209#elif ECB_GCC_VERSION(2,5)
210 #define ecb_inline static __inline__
211#elif ECB_C99
212 #define ecb_inline static inline
213#else
214 #define ecb_inline static
215#endif
216
217#if ECB_GCC_VERSION(3,3)
218 #define ecb_restrict __restrict__
219#elif ECB_C99
220 #define ecb_restrict restrict
221#else
222 #define ecb_restrict
223#endif
224
225typedef int ecb_bool;
226
227#define ECB_CONCAT_(a, b) a ## b
228#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
229#define ECB_STRINGIFY_(a) # a
230#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)
231
232#define ecb_function_ ecb_inline
33 233
34#if ECB_GCC_VERSION(3,1) 234#if ECB_GCC_VERSION(3,1)
35# define ecb_attribute(attrlist) __attribute__(attrlist) 235 #define ecb_attribute(attrlist) __attribute__(attrlist)
36# define ecb_is_constant(c) __builtin_constant_p (c) 236 #define ecb_is_constant(expr) __builtin_constant_p (expr)
37# define ecb_expect(expr,value) __builtin_expect ((expr),(value)) 237 #define ecb_expect(expr,value) __builtin_expect ((expr),(value))
38# define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality) 238 #define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
39#else 239#else
40# define ecb_attribute(attrlist) 240 #define ecb_attribute(attrlist)
41# define ecb_is_constant(c) 0 241 #define ecb_is_constant(expr) 0
42# define ecb_expect(expr,value) (expr) 242 #define ecb_expect(expr,value) (expr)
43# define ecb_prefetch(addr,rw,locality) 243 #define ecb_prefetch(addr,rw,locality)
44#endif 244#endif
45 245
246/* no emulation for ecb_decltype */
46#if ECB_GCC_VERSION(4,5) 247#if ECB_GCC_VERSION(4,5)
47# define ecb_decltype(x) __decltype(x) 248 #define ecb_decltype(x) __decltype(x)
48#elif ECB_GCC_VERSION(3,0) 249#elif ECB_GCC_VERSION(3,0)
49# define ecb_decltype(x) typeof(x) 250 #define ecb_decltype(x) __typeof(x)
50#endif 251#endif
51 252
52#define ecb_noinline ecb_attribute ((noinline)) 253#define ecb_noinline ecb_attribute ((__noinline__))
53#define ecb_noreturn ecb_attribute ((noreturn))
54#define ecb_unused ecb_attribute ((unused)) 254#define ecb_unused ecb_attribute ((__unused__))
55#define ecb_const ecb_attribute ((const)) 255#define ecb_const ecb_attribute ((__const__))
56#define ecb_pure ecb_attribute ((pure)) 256#define ecb_pure ecb_attribute ((__pure__))
257
258#if ECB_C11
259 #define ecb_noreturn _Noreturn
260#else
261 #define ecb_noreturn ecb_attribute ((__noreturn__))
262#endif
263
264#if ECB_GCC_VERSION(4,3)
265 #define ecb_artificial ecb_attribute ((__artificial__))
57#define ecb_hot ecb_attribute ((hot)) // 4.3 266 #define ecb_hot ecb_attribute ((__hot__))
58#define ecb_cold ecb_attribute ((cold)) // 4.3 267 #define ecb_cold ecb_attribute ((__cold__))
268#else
269 #define ecb_artificial
270 #define ecb_hot
271 #define ecb_cold
272#endif
273
274/* put around conditional expressions if you are very sure that the */
275/* expression is mostly true or mostly false. note that these return */
276/* booleans, not the expression. */
277#define ecb_expect_false(expr) ecb_expect (!!(expr), 0)
278#define ecb_expect_true(expr) ecb_expect (!!(expr), 1)
279/* for compatibility to the rest of the world */
280#define ecb_likely(expr) ecb_expect_true (expr)
281#define ecb_unlikely(expr) ecb_expect_false (expr)
282
283/* count trailing zero bits and count # of one bits */
284#if ECB_GCC_VERSION(3,4)
285 /* we assume int == 32 bit, long == 32 or 64 bit and long long == 64 bit */
286 #define ecb_ld32(x) (__builtin_clz (x) ^ 31)
287 #define ecb_ld64(x) (__builtin_clzll (x) ^ 63)
288 #define ecb_ctz32(x) __builtin_ctz (x)
289 #define ecb_ctz64(x) __builtin_ctzll (x)
290 #define ecb_popcount32(x) __builtin_popcount (x)
291 /* no popcountll */
292#else
293 ecb_function_ int ecb_ctz32 (uint32_t x) ecb_const;
294 ecb_function_ int
295 ecb_ctz32 (uint32_t x)
296 {
297 int r = 0;
298
299 x &= ~x + 1; /* this isolates the lowest bit */
300
301#if ECB_branchless_on_i386
302 r += !!(x & 0xaaaaaaaa) << 0;
303 r += !!(x & 0xcccccccc) << 1;
304 r += !!(x & 0xf0f0f0f0) << 2;
305 r += !!(x & 0xff00ff00) << 3;
306 r += !!(x & 0xffff0000) << 4;
307#else
308 if (x & 0xaaaaaaaa) r += 1;
309 if (x & 0xcccccccc) r += 2;
310 if (x & 0xf0f0f0f0) r += 4;
311 if (x & 0xff00ff00) r += 8;
312 if (x & 0xffff0000) r += 16;
313#endif
314
315 return r;
316 }
317
318 ecb_function_ int ecb_ctz64 (uint64_t x) ecb_const;
319 ecb_function_ int
320 ecb_ctz64 (uint64_t x)
321 {
322 int shift = x & 0xffffffffU ? 0 : 32;
323 return ecb_ctz32 (x >> shift) + shift;
324 }
325
326 ecb_function_ int ecb_popcount32 (uint32_t x) ecb_const;
327 ecb_function_ int
328 ecb_popcount32 (uint32_t x)
329 {
330 x -= (x >> 1) & 0x55555555;
331 x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
332 x = ((x >> 4) + x) & 0x0f0f0f0f;
333 x *= 0x01010101;
334
335 return x >> 24;
336 }
337
338 ecb_function_ int ecb_ld32 (uint32_t x) ecb_const;
339 ecb_function_ int ecb_ld32 (uint32_t x)
340 {
341 int r = 0;
342
343 if (x >> 16) { x >>= 16; r += 16; }
344 if (x >> 8) { x >>= 8; r += 8; }
345 if (x >> 4) { x >>= 4; r += 4; }
346 if (x >> 2) { x >>= 2; r += 2; }
347 if (x >> 1) { r += 1; }
348
349 return r;
350 }
351
352 ecb_function_ int ecb_ld64 (uint64_t x) ecb_const;
353 ecb_function_ int ecb_ld64 (uint64_t x)
354 {
355 int r = 0;
356
357 if (x >> 32) { x >>= 32; r += 32; }
358
359 return r + ecb_ld32 (x);
360 }
361#endif
362
363ecb_function_ ecb_bool ecb_is_pot32 (uint32_t x) ecb_const;
364ecb_function_ ecb_bool ecb_is_pot32 (uint32_t x) { return !(x & (x - 1)); }
365ecb_function_ ecb_bool ecb_is_pot64 (uint64_t x) ecb_const;
366ecb_function_ ecb_bool ecb_is_pot64 (uint64_t x) { return !(x & (x - 1)); }
367
368ecb_function_ uint8_t ecb_bitrev8 (uint8_t x) ecb_const;
369ecb_function_ uint8_t ecb_bitrev8 (uint8_t x)
370{
371 return ( (x * 0x0802U & 0x22110U)
372 | (x * 0x8020U & 0x88440U)) * 0x10101U >> 16;
373}
374
375ecb_function_ uint16_t ecb_bitrev16 (uint16_t x) ecb_const;
376ecb_function_ uint16_t ecb_bitrev16 (uint16_t x)
377{
378 x = ((x >> 1) & 0x5555) | ((x & 0x5555) << 1);
379 x = ((x >> 2) & 0x3333) | ((x & 0x3333) << 2);
380 x = ((x >> 4) & 0x0f0f) | ((x & 0x0f0f) << 4);
381 x = ( x >> 8 ) | ( x << 8);
382
383 return x;
384}
385
386ecb_function_ uint32_t ecb_bitrev32 (uint32_t x) ecb_const;
387ecb_function_ uint32_t ecb_bitrev32 (uint32_t x)
388{
389 x = ((x >> 1) & 0x55555555) | ((x & 0x55555555) << 1);
390 x = ((x >> 2) & 0x33333333) | ((x & 0x33333333) << 2);
391 x = ((x >> 4) & 0x0f0f0f0f) | ((x & 0x0f0f0f0f) << 4);
392 x = ((x >> 8) & 0x00ff00ff) | ((x & 0x00ff00ff) << 8);
393 x = ( x >> 16 ) | ( x << 16);
394
395 return x;
396}
397
398/* popcount64 is only available on 64 bit cpus as gcc builtin */
399/* so for this version we are lazy */
400ecb_function_ int ecb_popcount64 (uint64_t x) ecb_const;
401ecb_function_ int
402ecb_popcount64 (uint64_t x)
403{
404 return ecb_popcount32 (x) + ecb_popcount32 (x >> 32);
405}
406
407ecb_inline uint8_t ecb_rotl8 (uint8_t x, unsigned int count) ecb_const;
408ecb_inline uint8_t ecb_rotr8 (uint8_t x, unsigned int count) ecb_const;
409ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) ecb_const;
410ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) ecb_const;
411ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
412ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
413ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) ecb_const;
414ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) ecb_const;
415
416ecb_inline uint8_t ecb_rotl8 (uint8_t x, unsigned int count) { return (x >> ( 8 - count)) | (x << count); }
417ecb_inline uint8_t ecb_rotr8 (uint8_t x, unsigned int count) { return (x << ( 8 - count)) | (x >> count); }
418ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) { return (x >> (16 - count)) | (x << count); }
419ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) { return (x << (16 - count)) | (x >> count); }
420ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) { return (x >> (32 - count)) | (x << count); }
421ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) { return (x << (32 - count)) | (x >> count); }
422ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) { return (x >> (64 - count)) | (x << count); }
423ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) { return (x << (64 - count)) | (x >> count); }
424
425#if ECB_GCC_VERSION(4,3)
426 #define ecb_bswap16(x) (__builtin_bswap32 (x) >> 16)
427 #define ecb_bswap32(x) __builtin_bswap32 (x)
428 #define ecb_bswap64(x) __builtin_bswap64 (x)
429#else
430 ecb_function_ uint16_t ecb_bswap16 (uint16_t x) ecb_const;
431 ecb_function_ uint16_t
432 ecb_bswap16 (uint16_t x)
433 {
434 return ecb_rotl16 (x, 8);
435 }
436
437 ecb_function_ uint32_t ecb_bswap32 (uint32_t x) ecb_const;
438 ecb_function_ uint32_t
439 ecb_bswap32 (uint32_t x)
440 {
441 return (((uint32_t)ecb_bswap16 (x)) << 16) | ecb_bswap16 (x >> 16);
442 }
443
444 ecb_function_ uint64_t ecb_bswap64 (uint64_t x) ecb_const;
445 ecb_function_ uint64_t
446 ecb_bswap64 (uint64_t x)
447 {
448 return (((uint64_t)ecb_bswap32 (x)) << 32) | ecb_bswap32 (x >> 32);
449 }
450#endif
59 451
60#if ECB_GCC_VERSION(4,5) 452#if ECB_GCC_VERSION(4,5)
61# define ecb_unreachable() __builtin_unreachable () 453 #define ecb_unreachable() __builtin_unreachable ()
62#else 454#else
63 // this seems to work fine, but gcc always emits a warning for it :/ 455 /* this seems to work fine, but gcc always emits a warning for it :/ */
64 static inline void ecb_unreachable () ecb_attribute ((noreturn)); 456 ecb_inline void ecb_unreachable (void) ecb_noreturn;
65 static inline void ecb_unreachable () { } 457 ecb_inline void ecb_unreachable (void) { }
66#endif 458#endif
67 459
68// put into ifs if you are very sure that the expression
69// is mostly true or mosty false. note that these return
70// booleans, not the expression.
71#define ecb_expect_false(expr) ecb_expect ((expr) ? 1 : 0, 0)
72#define ecb_expect_true(expr) ecb_expect ((expr) ? 1 : 0, 1)
73
74// try to tell the compiler that some condition is definitely true 460/* try to tell the compiler that some condition is definitely true */
75#define ecb_assume(cond) do { if (!(cond)) unreachable (); } while (0) 461#define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0)
76 462
77// count trailing zero bits and count # of one bits 463ecb_inline unsigned char ecb_byteorder_helper (void) ecb_const;
78#if ECB_GCC_VERSION(3,4) 464ecb_inline unsigned char
79static inline int ecb_ctz (unsigned int x) { return __builtin_ctz (x); } 465ecb_byteorder_helper (void)
80static inline int ecb_popcount (unsigned int x) { return __builtin_popcount (x); }
81#else
82static int ecb_ctz (unsigned int x) ecb_const
83{ 466{
84 int r = 0; 467 const uint32_t u = 0x11223344;
85 468 return *(unsigned char *)&u;
86 x &= -x; // this isolates the lowest bit
87
88 if (x & 0xaaaaaaaa) r += 1;
89 if (x & 0xcccccccc) r += 2;
90 if (x & 0xf0f0f0f0) r += 4;
91 if (x & 0xff00ff00) r += 8;
92 if (x & 0xffff0000) r += 16;
93
94 return r;
95} 469}
96 470
97static int ecb_popcount (unsigned int x) ecb_const 471ecb_inline ecb_bool ecb_big_endian (void) ecb_const;
98{ 472ecb_inline ecb_bool ecb_big_endian (void) { return ecb_byteorder_helper () == 0x11; }
99 x -= (x >> 1) & 0x55555555; 473ecb_inline ecb_bool ecb_little_endian (void) ecb_const;
100 x = ((x >> 2) & 0x33333333) + (x & 0x33333333); 474ecb_inline ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44; }
101 x = ((x >> 4) + x) & 0x0f0f0f0f;
102 x *= 0x01010101;
103 475
104 return x >> 24; 476#if ECB_GCC_VERSION(3,0) || ECB_C99
105} 477 #define ecb_mod(m,n) ((m) % (n) + ((m) % (n) < 0 ? (n) : 0))
478#else
479 #define ecb_mod(m,n) ((m) < 0 ? ((n) - 1 - ((-1 - (m)) % (n))) : ((m) % (n)))
106#endif 480#endif
107 481
482#if __cplusplus
483 template<typename T>
484 static inline T ecb_div_rd (T val, T div)
485 {
486 return val < 0 ? - ((-val + div - 1) / div) : (val ) / div;
487 }
488 template<typename T>
489 static inline T ecb_div_ru (T val, T div)
490 {
491 return val < 0 ? - ((-val ) / div) : (val + div - 1) / div;
492 }
493#else
494 #define ecb_div_rd(val,div) ((val) < 0 ? - ((-(val) + (div) - 1) / (div)) : ((val) ) / (div))
495 #define ecb_div_ru(val,div) ((val) < 0 ? - ((-(val) ) / (div)) : ((val) + (div) - 1) / (div))
108#endif 496#endif
109 497
498#if ecb_cplusplus_does_not_suck
499 /* does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm) */
500 template<typename T, int N>
501 static inline int ecb_array_length (const T (&arr)[N])
502 {
503 return N;
504 }
505#else
506 #define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
507#endif
508
509#endif
510

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