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 /* _MSC_VER || __BORLANDC__ */
    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 ECB_branchless_on_i386
    r += !!(x & 0xaaaaaaaa) << 0;
    r += !!(x & 0xcccccccc) << 1;
    r += !!(x & 0xf0f0f0f0) << 2;
    r += !!(x & 0xff00ff00) << 3;
    r += !!(x & 0xffff0000) << 4;
#else
    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;
#endif

    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_ctz32 (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 = 0;

    if (x >> 16) { x >>= 16; r += 16; }
    if (x >>  8) { x >>=  8; r +=  8; }
    if (x >>  4) { x >>=  4; r +=  4; }
    if (x >>  2) { x >>=  2; r +=  2; }
    if (x >>  1) {           r +=  1; }

    return r;
  }

  ecb_function_ int ecb_ld64 (uint64_t x) ecb_const;
  ecb_function_ int ecb_ld64 (uint64_t x)
  {
    int r = 0;

    if (x >> 32) { x >>= 32; r += 32; }

    return r + ecb_ld32 (x);
  }
#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);
}

ecb_inline uint8_t  ecb_rotl8  (uint8_t  x, unsigned int count) ecb_const;
ecb_inline uint8_t  ecb_rotr8  (uint8_t  x, unsigned int count) ecb_const;
ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) ecb_const;
ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) ecb_const;
ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) ecb_const;
ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) ecb_const;

ecb_inline uint8_t  ecb_rotl8  (uint8_t  x, unsigned int count) { return (x >> ( 8 - count)) | (x << count); }
ecb_inline uint8_t  ecb_rotr8  (uint8_t  x, unsigned int count) { return (x << ( 8 - count)) | (x >> count); }
ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) { return (x >> (16 - count)) | (x << count); }
ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) { return (x << (16 - count)) | (x >> count); }
ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) { return (x >> (32 - count)) | (x << count); }
ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) { return (x << (32 - count)) | (x >> count); }
ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) { return (x >> (64 - count)) | (x << count); }
ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) { return (x << (64 - count)) | (x >> count); }

#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_ uint16_t ecb_bswap16 (uint16_t x) ecb_const;
  ecb_function_ uint16_t
  ecb_bswap16 (uint16_t x)
  {
    return ecb_rotl16 (x, 8);
  }

  ecb_function_ uint32_t ecb_bswap32 (uint32_t x) ecb_const;
  ecb_function_ uint32_t
  ecb_bswap32 (uint32_t x)
  {
    return (((uint32_t)ecb_bswap16 (x)) << 16) | ecb_bswap16 (x >> 16);
  }

  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

#endif

Revision:	1.3
Committed:	Mon Jun 20 07:28:14 2011 UTC (12 years, 11 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-3_93, rel-3_92, rel-3_91
Changes since 1.2:	+43 -57 lines
Log Message:	* empty log message *
#	Content
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	#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 /* _MSC_VER \|\| __BORLANDC__ */
44	typedef signed __int64 int64_t;
45	typedef unsigned __int64 uint64_t;
46	#endif
47	#else
48	#include <inttypes.h>
49	#endif
50
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	#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	#endif
65
66	#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	#else
83	#define ecb_restrict
84	#endif
85
86	typedef int ecb_bool;
87
88	#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	#define ecb_function_ ecb_inline
94
95	#if ECB_GCC_VERSION(3,1)
96	#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	#endif
106
107	/* no emulation for ecb_decltype */
108	#if ECB_GCC_VERSION(4,5)
109	#define ecb_decltype(x) __decltype(x)
110	#elif ECB_GCC_VERSION(3,0)
111	#define ecb_decltype(x) __typeof(x)
112	#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	#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	#define ecb_expect_false(expr) ecb_expect (!!(expr), 0)
134	#define ecb_expect_true(expr) ecb_expect (!!(expr), 1)
135	/* for compatibility to the rest of the world */
136	#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	/* 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	#else
149	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 ECB_branchless_on_i386
158	r += !!(x & 0xaaaaaaaa) << 0;
159	r += !!(x & 0xcccccccc) << 1;
160	r += !!(x & 0xf0f0f0f0) << 2;
161	r += !!(x & 0xff00ff00) << 3;
162	r += !!(x & 0xffff0000) << 4;
163	#else
164	if (x & 0xaaaaaaaa) r += 1;
165	if (x & 0xcccccccc) r += 2;
166	if (x & 0xf0f0f0f0) r += 4;
167	if (x & 0xff00ff00) r += 8;
168	if (x & 0xffff0000) r += 16;
169	#endif
170
171	return r;
172	}
173
174	ecb_function_ int ecb_ctz64 (uint64_t x) ecb_const;
175	ecb_function_ int
176	ecb_ctz64 (uint64_t x)
177	{
178	int shift = x & 0xffffffffU ? 0 : 32;
179	return ecb_ctz32 (x >> shift) + shift;
180	}
181
182	ecb_function_ int ecb_popcount32 (uint32_t x) ecb_const;
183	ecb_function_ int
184	ecb_popcount32 (uint32_t x)
185	{
186	x -= (x >> 1) & 0x55555555;
187	x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
188	x = ((x >> 4) + x) & 0x0f0f0f0f;
189	x *= 0x01010101;
190
191	return x >> 24;
192	}
193
194	/* you have the choice beetween something with a table lookup, */
195	/* something using lots of bit arithmetic and a simple loop */
196	/* we went for the loop */
197	ecb_function_ int ecb_ld32 (uint32_t x) ecb_const;
198	ecb_function_ int ecb_ld32 (uint32_t x)
199	{
200	int r = 0;
201
202	if (x >> 16) { x >>= 16; r += 16; }
203	if (x >> 8) { x >>= 8; r += 8; }
204	if (x >> 4) { x >>= 4; r += 4; }
205	if (x >> 2) { x >>= 2; r += 2; }
206	if (x >> 1) { r += 1; }
207
208	return r;
209	}
210
211	ecb_function_ int ecb_ld64 (uint64_t x) ecb_const;
212	ecb_function_ int ecb_ld64 (uint64_t x)
213	{
214	int r = 0;
215
216	if (x >> 32) { x >>= 32; r += 32; }
217
218	return r + ecb_ld32 (x);
219	}
220	#endif
221
222	/* popcount64 is only available on 64 bit cpus as gcc builtin */
223	/* so for this version we are lazy */
224	ecb_function_ int ecb_popcount64 (uint64_t x) ecb_const;
225	ecb_function_ int
226	ecb_popcount64 (uint64_t x)
227	{
228	return ecb_popcount32 (x) + ecb_popcount32 (x >> 32);
229	}
230
231	ecb_inline uint8_t ecb_rotl8 (uint8_t x, unsigned int count) ecb_const;
232	ecb_inline uint8_t ecb_rotr8 (uint8_t x, unsigned int count) ecb_const;
233	ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) ecb_const;
234	ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) ecb_const;
235	ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
236	ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
237	ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) ecb_const;
238	ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) ecb_const;
239
240	ecb_inline uint8_t ecb_rotl8 (uint8_t x, unsigned int count) { return (x >> ( 8 - count)) \| (x << count); }
241	ecb_inline uint8_t ecb_rotr8 (uint8_t x, unsigned int count) { return (x << ( 8 - count)) \| (x >> count); }
242	ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) { return (x >> (16 - count)) \| (x << count); }
243	ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) { return (x << (16 - count)) \| (x >> count); }
244	ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) { return (x >> (32 - count)) \| (x << count); }
245	ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) { return (x << (32 - count)) \| (x >> count); }
246	ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) { return (x >> (64 - count)) \| (x << count); }
247	ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) { return (x << (64 - count)) \| (x >> count); }
248
249	#if ECB_GCC_VERSION(4,3)
250	#define ecb_bswap16(x) (__builtin_bswap32 (x) >> 16)
251	#define ecb_bswap32(x) __builtin_bswap32 (x)
252	#define ecb_bswap64(x) __builtin_bswap64 (x)
253	#else
254	ecb_function_ uint16_t ecb_bswap16 (uint16_t x) ecb_const;
255	ecb_function_ uint16_t
256	ecb_bswap16 (uint16_t x)
257	{
258	return ecb_rotl16 (x, 8);
259	}
260
261	ecb_function_ uint32_t ecb_bswap32 (uint32_t x) ecb_const;
262	ecb_function_ uint32_t
263	ecb_bswap32 (uint32_t x)
264	{
265	return (((uint32_t)ecb_bswap16 (x)) << 16) \| ecb_bswap16 (x >> 16);
266	}
267
268	ecb_function_ uint64_t ecb_bswap64 (uint64_t x) ecb_const;
269	ecb_function_ uint64_t
270	ecb_bswap64 (uint64_t x)
271	{
272	return (((uint64_t)ecb_bswap32 (x)) << 32) \| ecb_bswap32 (x >> 32);
273	}
274	#endif
275
276	#if ECB_GCC_VERSION(4,5)
277	#define ecb_unreachable() __builtin_unreachable ()
278	#else
279	/* this seems to work fine, but gcc always emits a warning for it :/ */
280	ecb_function_ void ecb_unreachable (void) ecb_noreturn;
281	ecb_function_ void ecb_unreachable (void) { }
282	#endif
283
284	/* try to tell the compiler that some condition is definitely true */
285	#define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0)
286
287	ecb_function_ unsigned char ecb_byteorder_helper (void) ecb_const;
288	ecb_function_ unsigned char
289	ecb_byteorder_helper (void)
290	{
291	const uint32_t u = 0x11223344;
292	return (unsigned char )&u;
293	}
294
295	ecb_function_ ecb_bool ecb_big_endian (void) ecb_const;
296	ecb_function_ ecb_bool ecb_big_endian (void) { return ecb_byteorder_helper () == 0x11; }
297	ecb_function_ ecb_bool ecb_little_endian (void) ecb_const;
298	ecb_function_ ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44; }
299
300	#if ECB_GCC_VERSION(3,0) \|\| ECB_C99
301	#define ecb_mod(m,n) ((m) % (n) + ((m) % (n) < 0 ? (n) : 0))
302	#else
303	#define ecb_mod(m,n) ((m) < 0 ? ((n) - 1 - ((-1 - (m)) % (n))) : ((m) % (n)))
304	#endif
305
306	#if ecb_cplusplus_does_not_suck
307	/* does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm) */
308	template<typename T, int N>
309	static inline int ecb_array_length (const T (&arr)[N])
310	{
311	return N;
312	}
313	#else
314	#define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
315	#endif
316
317	#endif
318