libeio/ecb.h

/*
 * libecb - http://software.schmorp.de/pkg/libecb
 *
 * Copyright (©) 2009-2011 Marc Alexander Lehmann <libecb@schmorp.de>
 * Copyright (©) 2011 Emanuele Giaquinta
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 *
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef ECB_H
#define ECB_H

#ifdef _WIN32
  typedef   signed char   int8_t;
  typedef unsigned char  uint8_t;
  typedef   signed short  int16_t;
  typedef unsigned short uint16_t;
  typedef   signed int    int32_t;
  typedef unsigned int   uint32_t;
  #if __GNUC__
    typedef   signed long long int64_t;
    typedef unsigned long long uint64_t;
  #else
    typedef   signed __int64   int64_t;
    typedef unsigned __int64   uint64_t;
  #endif
#else
  #include <inttypes.h>
#endif

/* many compilers define _GNUC_ to some versions but then only implement
 * what their idiot authors think are the "more important" extensions,
 * causing enourmous grief in return for some better fake benchmark numbers.
 * or so.
 * we try to detect these and simply assume they are not gcc - if they have
 * an issue with that they should have done it right in the first place.
 */
#ifndef ECB_GCC_VERSION
  #if !defined(__GNUC_MINOR__) || defined(__INTEL_COMPILER) || defined(__SUNPRO_C) || defined(__SUNPRO_CC) || defined(__llvm__) || defined(__clang__)
    #define ECB_GCC_VERSION(major,minor) 0
  #else
    #define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
  #endif
#endif

#define ECB_C99 (__STDC_VERSION__ >= 199901L)

#if __cplusplus
  #define ecb_inline static inline
#elif ECB_GCC_VERSION(2,5)
  #define ecb_inline static __inline__
#elif ECB_C99
  #define ecb_inline static inline
#else
  #define ecb_inline static
#endif

#if ECB_GCC_VERSION(3,3)
  #define ecb_restrict __restrict__
#elif ECB_C99
  #define ecb_restrict restrict
#else
  #define ecb_restrict
#endif

typedef int ecb_bool;

#define ECB_CONCAT_(a, b) a ## b
#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
#define ECB_STRINGIFY_(a) # a
#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)

#define ecb_function_ ecb_inline

#if ECB_GCC_VERSION(3,1)
  #define ecb_attribute(attrlist)        __attribute__(attrlist)
  #define ecb_is_constant(expr)          __builtin_constant_p (expr)
  #define ecb_expect(expr,value)         __builtin_expect ((expr),(value))
  #define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
#else
  #define ecb_attribute(attrlist)
  #define ecb_is_constant(expr)          0
  #define ecb_expect(expr,value)         (expr)
  #define ecb_prefetch(addr,rw,locality)
#endif

/* no emulation for ecb_decltype */
#if ECB_GCC_VERSION(4,5)
  #define ecb_decltype(x) __decltype(x)
#elif ECB_GCC_VERSION(3,0)
  #define ecb_decltype(x) __typeof(x)
#endif

#define ecb_noinline   ecb_attribute ((__noinline__))
#define ecb_noreturn   ecb_attribute ((__noreturn__))
#define ecb_unused     ecb_attribute ((__unused__))
#define ecb_const      ecb_attribute ((__const__))
#define ecb_pure       ecb_attribute ((__pure__))

#if ECB_GCC_VERSION(4,3)
  #define ecb_artificial ecb_attribute ((__artificial__))
  #define ecb_hot        ecb_attribute ((__hot__))
  #define ecb_cold       ecb_attribute ((__cold__))
#else
  #define ecb_artificial
  #define ecb_hot
  #define ecb_cold
#endif

/* put around conditional expressions if you are very sure that the  */
/* expression is mostly true or mostly false. note that these return */
/* booleans, not the expression.                                     */
#define ecb_expect_false(expr) ecb_expect (!!(expr), 0)
#define ecb_expect_true(expr)  ecb_expect (!!(expr), 1)
/* for compatibility to the rest of the world */
#define ecb_likely(expr)   ecb_expect_true  (expr)
#define ecb_unlikely(expr) ecb_expect_false (expr)

/* count trailing zero bits and count # of one bits */
#if ECB_GCC_VERSION(3,4)
  /* we assume int == 32 bit, long == 32 or 64 bit and long long == 64 bit */
  #define ecb_ld32(x)      (__builtin_clz      (x) ^ 31)
  #define ecb_ld64(x)      (__builtin_clzll    (x) ^ 63)
  #define ecb_ctz32(x)      __builtin_ctz      (x)
  #define ecb_ctz64(x)      __builtin_ctzll    (x)
  #define ecb_popcount32(x) __builtin_popcount (x)
  /* no popcountll */
#else
  ecb_function_ int ecb_ctz32 (uint32_t x) ecb_const;
  ecb_function_ int
  ecb_ctz32 (uint32_t x)
  {
    int r = 0;

    x &= ~x + 1; /* this isolates the lowest bit */

    if (x & 0xaaaaaaaa) r +=  1;
    if (x & 0xcccccccc) r +=  2;
    if (x & 0xf0f0f0f0) r +=  4;
    if (x & 0xff00ff00) r +=  8;
    if (x & 0xffff0000) r += 16;

    return r;
  }

  ecb_function_ int ecb_ctz64 (uint64_t x) ecb_const;
  ecb_function_ int
  ecb_ctz64 (uint64_t x)
  {
    int shift = x & 0xffffffffU ? 0 : 32;
    return ecb_ctz (x >> shift) + shift;
  }

  ecb_function_ int ecb_popcount32 (uint32_t x) ecb_const;
  ecb_function_ int
  ecb_popcount32 (uint32_t x)
  {
    x -=  (x >> 1) & 0x55555555;
    x  = ((x >> 2) & 0x33333333) + (x & 0x33333333);
    x  = ((x >> 4) + x) & 0x0f0f0f0f;
    x *= 0x01010101;

    return x >> 24;
  }

  /* you have the choice beetween something with a table lookup, */
  /* something using lots of bit arithmetic and a simple loop */
  /* we went for the loop */
  ecb_function_ int ecb_ld32 (uint32_t x) ecb_const;
  ecb_function_ int ecb_ld32 (uint32_t x)
  {
    int r = -1;

    do
      {
        x >>= 1;
        ++r;
      }
    while (x);

    return r;
  }

  ecb_function_ int ecb_ld64 (uint64_t x) ecb_const;
  ecb_function_ int ecb_ld64 (uint64_t x)
  {
    int r = -1;

    do
      {
        x >>= 1;
        ++r;
      }
    while (x);

    return r;
  }
#endif

/* popcount64 is only available on 64 bit cpus as gcc builtin */
/* so for this version we are lazy */
ecb_function_ int ecb_popcount64 (uint64_t x) ecb_const;
ecb_function_ int
ecb_popcount64 (uint64_t x)
{
  return ecb_popcount32 (x) + ecb_popcount32 (x >> 32);
}

#if ECB_GCC_VERSION(4,3)
  #define ecb_bswap16(x) (__builtin_bswap32 (x) >> 16)
  #define ecb_bswap32(x)  __builtin_bswap32 (x)
  #define ecb_bswap64(x)  __builtin_bswap64 (x)
#else
  ecb_function_ uint32_t ecb_bswap16 (uint32_t x) ecb_const;
  ecb_function_ uint32_t
  ecb_bswap16 (uint32_t x)
  {
    return ((x >>  8) & 0xff)
        |  ((x <<  8) & 0x00ff0000)
        |  (x << 24);
  }

  ecb_function_ uint32_t ecb_bswap32 (uint32_t x) ecb_const;
  ecb_function_ uint32_t
  ecb_bswap32 (uint32_t x)
  {
    return (x >> 24)
        | ((x >>  8) & 0x0000ff00)
        | ((x <<  8) & 0x00ff0000)
        |  (x << 24);
  }

  ecb_function_ uint64_t ecb_bswap64 (uint64_t x) ecb_const;
  ecb_function_ uint64_t
  ecb_bswap64 (uint64_t x)
  {
    return (((uint64_t)ecb_bswap32 (x)) << 32)
         | ecb_bswap32 (x >> 32);
  }
#endif

#if ECB_GCC_VERSION(4,5)
  #define ecb_unreachable() __builtin_unreachable ()
#else
  /* this seems to work fine, but gcc always emits a warning for it :/ */
  ecb_function_ void ecb_unreachable (void) ecb_noreturn;
  ecb_function_ void ecb_unreachable (void) { }
#endif

/* try to tell the compiler that some condition is definitely true */
#define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0)

ecb_function_ unsigned char ecb_byteorder_helper (void) ecb_const;
ecb_function_ unsigned char
ecb_byteorder_helper (void)
{
  const uint32_t u = 0x11223344;
  return *(unsigned char *)&u;
}

ecb_function_ ecb_bool ecb_big_endian    (void) ecb_const;
ecb_function_ ecb_bool ecb_big_endian    (void) { return ecb_byteorder_helper () == 0x11; }
ecb_function_ ecb_bool ecb_little_endian (void) ecb_const;
ecb_function_ ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44; }

#if ECB_GCC_VERSION(3,0) || ECB_C99
  #define ecb_mod(m,n) ((m) % (n) + ((m) % (n) < 0 ? (n) : 0))
#else
  #define ecb_mod(m,n) ((m) < 0 ? ((n) - 1 - ((-1 - (m)) % (n))) : ((m) % (n)))
#endif

#if ecb_cplusplus_does_not_suck
  /* does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm) */
  template<typename T, int N>
  static inline int ecb_array_length (const T (&arr)[N])
  {
    return N;
  }
#else
  #define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
#endif

ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
ecb_inline uint32_t
ecb_rotr32 (uint32_t x, unsigned int count)
{
  return (x << (32 - count)) | (x >> count);
}

ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
ecb_inline uint32_t
ecb_rotl32 (uint32_t x, unsigned int count)
{
  return (x >> (32 - count)) | (x << count);
}

ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) ecb_const;
ecb_inline uint64_t
ecb_rotr64 (uint64_t x, unsigned int count)
{
  return (x << (64 - count)) | (x >> count);
}

ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) ecb_const;
ecb_inline uint64_t
ecb_rotl64 (uint64_t x, unsigned int count)
{
  return (x >> (64 - count)) | (x << count);
}

#endif

Revision:	1.2
Committed:	Fri Jun 17 18:55:42 2011 UTC (12 years, 11 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.1:	+219 -108 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/*
2			* libecb - http://software.schmorp.de/pkg/libecb
3			*
4			* Copyright (©) 2009-2011 Marc Alexander Lehmann <libecb@schmorp.de>
5			* Copyright (©) 2011 Emanuele Giaquinta
6			* All rights reserved.
7			*
8			* Redistribution and use in source and binary forms, with or without modifica-
9			* tion, are permitted provided that the following conditions are met:
10			*
11			* 1. Redistributions of source code must retain the above copyright notice,
12			* this list of conditions and the following disclaimer.
13			*
14			* 2. Redistributions in binary form must reproduce the above copyright
15			* notice, this list of conditions and the following disclaimer in the
16			* documentation and/or other materials provided with the distribution.
17			*
18			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
19			* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
20			* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
21			* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
22			* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23			* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
24			* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25			* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
26			* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
27			* OF THE POSSIBILITY OF SUCH DAMAGE.
28			*/
29
30			#ifndef ECB_H
31			#define ECB_H
32
33	root	1.2	#ifdef _WIN32
34			typedef signed char int8_t;
35			typedef unsigned char uint8_t;
36			typedef signed short int16_t;
37			typedef unsigned short uint16_t;
38			typedef signed int int32_t;
39			typedef unsigned int uint32_t;
40			#if __GNUC__
41			typedef signed long long int64_t;
42			typedef unsigned long long uint64_t;
43			#else
44			typedef signed __int64 int64_t;
45			typedef unsigned __int64 uint64_t;
46			#endif
47			#else
48			#include <inttypes.h>
49			#endif
50	root	1.1
51			/* many compilers define _GNUC_ to some versions but then only implement
52			* what their idiot authors think are the "more important" extensions,
53			* causing enourmous grief in return for some better fake benchmark numbers.
54			* or so.
55			* we try to detect these and simply assume they are not gcc - if they have
56			* an issue with that they should have done it right in the first place.
57			*/
58			#ifndef ECB_GCC_VERSION
59	root	1.2	#if !defined(__GNUC_MINOR__) \|\| defined(__INTEL_COMPILER) \|\| defined(__SUNPRO_C) \|\| defined(__SUNPRO_CC) \|\| defined(__llvm__) \|\| defined(__clang__)
60			#define ECB_GCC_VERSION(major,minor) 0
61			#else
62			#define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) \|\| (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
63			#endif
64	root	1.1	#endif
65
66	root	1.2	#define ECB_C99 (__STDC_VERSION__ >= 199901L)
67
68			#if __cplusplus
69			#define ecb_inline static inline
70			#elif ECB_GCC_VERSION(2,5)
71			#define ecb_inline static __inline__
72			#elif ECB_C99
73			#define ecb_inline static inline
74			#else
75			#define ecb_inline static
76			#endif
77
78			#if ECB_GCC_VERSION(3,3)
79			#define ecb_restrict __restrict__
80			#elif ECB_C99
81			#define ecb_restrict restrict
82	root	1.1	#else
83	root	1.2	#define ecb_restrict
84	root	1.1	#endif
85
86	root	1.2	typedef int ecb_bool;
87
88	root	1.1	#define ECB_CONCAT_(a, b) a ## b
89			#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
90			#define ECB_STRINGIFY_(a) # a
91			#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)
92
93	root	1.2	#define ecb_function_ ecb_inline
94	root	1.1
95			#if ECB_GCC_VERSION(3,1)
96	root	1.2	#define ecb_attribute(attrlist) __attribute__(attrlist)
97			#define ecb_is_constant(expr) __builtin_constant_p (expr)
98			#define ecb_expect(expr,value) __builtin_expect ((expr),(value))
99			#define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
100			#else
101			#define ecb_attribute(attrlist)
102			#define ecb_is_constant(expr) 0
103			#define ecb_expect(expr,value) (expr)
104			#define ecb_prefetch(addr,rw,locality)
105	root	1.1	#endif
106
107			/* no emulation for ecb_decltype */
108			#if ECB_GCC_VERSION(4,5)
109	root	1.2	#define ecb_decltype(x) __decltype(x)
110	root	1.1	#elif ECB_GCC_VERSION(3,0)
111	root	1.2	#define ecb_decltype(x) __typeof(x)
112	root	1.1	#endif
113
114			#define ecb_noinline ecb_attribute ((__noinline__))
115			#define ecb_noreturn ecb_attribute ((__noreturn__))
116			#define ecb_unused ecb_attribute ((__unused__))
117			#define ecb_const ecb_attribute ((__const__))
118			#define ecb_pure ecb_attribute ((__pure__))
119
120	root	1.2	#if ECB_GCC_VERSION(4,3)
121			#define ecb_artificial ecb_attribute ((__artificial__))
122			#define ecb_hot ecb_attribute ((__hot__))
123			#define ecb_cold ecb_attribute ((__cold__))
124			#else
125			#define ecb_artificial
126			#define ecb_hot
127			#define ecb_cold
128			#endif
129
130			/* put around conditional expressions if you are very sure that the */
131			/* expression is mostly true or mostly false. note that these return */
132			/* booleans, not the expression. */
133	root	1.1	#define ecb_expect_false(expr) ecb_expect (!!(expr), 0)
134			#define ecb_expect_true(expr) ecb_expect (!!(expr), 1)
135	root	1.2	/* for compatibility to the rest of the world */
136	root	1.1	#define ecb_likely(expr) ecb_expect_true (expr)
137			#define ecb_unlikely(expr) ecb_expect_false (expr)
138
139			/* count trailing zero bits and count # of one bits */
140			#if ECB_GCC_VERSION(3,4)
141	root	1.2	/* we assume int == 32 bit, long == 32 or 64 bit and long long == 64 bit */
142			#define ecb_ld32(x) (__builtin_clz (x) ^ 31)
143			#define ecb_ld64(x) (__builtin_clzll (x) ^ 63)
144			#define ecb_ctz32(x) __builtin_ctz (x)
145			#define ecb_ctz64(x) __builtin_ctzll (x)
146			#define ecb_popcount32(x) __builtin_popcount (x)
147			/* no popcountll */
148	root	1.1	#else
149	root	1.2	ecb_function_ int ecb_ctz32 (uint32_t x) ecb_const;
150			ecb_function_ int
151			ecb_ctz32 (uint32_t x)
152			{
153			int r = 0;
154
155			x &= ~x + 1; /* this isolates the lowest bit */
156
157			if (x & 0xaaaaaaaa) r += 1;
158			if (x & 0xcccccccc) r += 2;
159			if (x & 0xf0f0f0f0) r += 4;
160			if (x & 0xff00ff00) r += 8;
161			if (x & 0xffff0000) r += 16;
162
163			return r;
164			}
165
166			ecb_function_ int ecb_ctz64 (uint64_t x) ecb_const;
167			ecb_function_ int
168			ecb_ctz64 (uint64_t x)
169			{
170			int shift = x & 0xffffffffU ? 0 : 32;
171			return ecb_ctz (x >> shift) + shift;
172			}
173
174			ecb_function_ int ecb_popcount32 (uint32_t x) ecb_const;
175			ecb_function_ int
176			ecb_popcount32 (uint32_t x)
177			{
178			x -= (x >> 1) & 0x55555555;
179			x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
180			x = ((x >> 4) + x) & 0x0f0f0f0f;
181			x *= 0x01010101;
182
183			return x >> 24;
184			}
185
186			/* you have the choice beetween something with a table lookup, */
187			/* something using lots of bit arithmetic and a simple loop */
188			/* we went for the loop */
189			ecb_function_ int ecb_ld32 (uint32_t x) ecb_const;
190			ecb_function_ int ecb_ld32 (uint32_t x)
191			{
192			int r = -1;
193
194			do
195			{
196			x >>= 1;
197			++r;
198			}
199			while (x);
200
201			return r;
202			}
203
204			ecb_function_ int ecb_ld64 (uint64_t x) ecb_const;
205			ecb_function_ int ecb_ld64 (uint64_t x)
206			{
207			int r = -1;
208
209			do
210			{
211			x >>= 1;
212			++r;
213			}
214			while (x);
215	root	1.1
216	root	1.2	return r;
217			}
218			#endif
219	root	1.1
220	root	1.2	/* popcount64 is only available on 64 bit cpus as gcc builtin */
221			/* so for this version we are lazy */
222			ecb_function_ int ecb_popcount64 (uint64_t x) ecb_const;
223			ecb_function_ int
224			ecb_popcount64 (uint64_t x)
225	root	1.1	{
226	root	1.2	return ecb_popcount32 (x) + ecb_popcount32 (x >> 32);
227	root	1.1	}
228
229			#if ECB_GCC_VERSION(4,3)
230	root	1.2	#define ecb_bswap16(x) (__builtin_bswap32 (x) >> 16)
231			#define ecb_bswap32(x) __builtin_bswap32 (x)
232			#define ecb_bswap64(x) __builtin_bswap64 (x)
233	root	1.1	#else
234	root	1.2	ecb_function_ uint32_t ecb_bswap16 (uint32_t x) ecb_const;
235			ecb_function_ uint32_t
236			ecb_bswap16 (uint32_t x)
237			{
238			return ((x >> 8) & 0xff)
239			\| ((x << 8) & 0x00ff0000)
240			\| (x << 24);
241			}
242
243			ecb_function_ uint32_t ecb_bswap32 (uint32_t x) ecb_const;
244			ecb_function_ uint32_t
245			ecb_bswap32 (uint32_t x)
246			{
247			return (x >> 24)
248			\| ((x >> 8) & 0x0000ff00)
249			\| ((x << 8) & 0x00ff0000)
250			\| (x << 24);
251			}
252
253			ecb_function_ uint64_t ecb_bswap64 (uint64_t x) ecb_const;
254			ecb_function_ uint64_t
255			ecb_bswap64 (uint64_t x)
256			{
257			return (((uint64_t)ecb_bswap32 (x)) << 32)
258			\| ecb_bswap32 (x >> 32);
259			}
260	root	1.1	#endif
261
262			#if ECB_GCC_VERSION(4,5)
263	root	1.2	#define ecb_unreachable() __builtin_unreachable ()
264	root	1.1	#else
265	root	1.2	/* this seems to work fine, but gcc always emits a warning for it :/ */
266			ecb_function_ void ecb_unreachable (void) ecb_noreturn;
267			ecb_function_ void ecb_unreachable (void) { }
268	root	1.1	#endif
269
270	root	1.2	/* try to tell the compiler that some condition is definitely true */
271			#define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0)
272
273			ecb_function_ unsigned char ecb_byteorder_helper (void) ecb_const;
274			ecb_function_ unsigned char
275	root	1.1	ecb_byteorder_helper (void)
276			{
277			const uint32_t u = 0x11223344;
278			return (unsigned char )&u;
279			}
280
281	root	1.2	ecb_function_ ecb_bool ecb_big_endian (void) ecb_const;
282			ecb_function_ ecb_bool ecb_big_endian (void) { return ecb_byteorder_helper () == 0x11; }
283			ecb_function_ ecb_bool ecb_little_endian (void) ecb_const;
284			ecb_function_ ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44; }
285	root	1.1
286	root	1.2	#if ECB_GCC_VERSION(3,0) \|\| ECB_C99
287			#define ecb_mod(m,n) ((m) % (n) + ((m) % (n) < 0 ? (n) : 0))
288	root	1.1	#else
289	root	1.2	#define ecb_mod(m,n) ((m) < 0 ? ((n) - 1 - ((-1 - (m)) % (n))) : ((m) % (n)))
290	root	1.1	#endif
291
292			#if ecb_cplusplus_does_not_suck
293	root	1.2	/* does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm) */
294			template<typename T, int N>
295			static inline int ecb_array_length (const T (&arr)[N])
296			{
297			return N;
298			}
299	root	1.1	#else
300	root	1.2	#define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
301	root	1.1	#endif
302
303	root	1.2	ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
304			ecb_inline uint32_t
305	root	1.1	ecb_rotr32 (uint32_t x, unsigned int count)
306			{
307			return (x << (32 - count)) \| (x >> count);
308			}
309
310	root	1.2	ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
311			ecb_inline uint32_t
312	root	1.1	ecb_rotl32 (uint32_t x, unsigned int count)
313			{
314			return (x >> (32 - count)) \| (x << count);
315			}
316
317	root	1.2	ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) ecb_const;
318			ecb_inline uint64_t
319			ecb_rotr64 (uint64_t x, unsigned int count)
320			{
321			return (x << (64 - count)) \| (x >> count);
322			}
323
324			ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) ecb_const;
325			ecb_inline uint64_t
326			ecb_rotl64 (uint64_t x, unsigned int count)
327			{
328			return (x >> (64 - count)) \| (x << count);
329			}
330
331	root	1.1	#endif
332