libecb/ecb.h

/*
 * libecb
 *
 * Copyright (©) 2009-2011 Marc Alexander Lehmann
 * 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

#include <inttypes.h>

/* many compilers define _GNUC_ to some versions but then only implement
 * what their idiot authors think are the "more important" extensions,
 * causing enourmous grief 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(__INTEL_COMPILER) || defined(__SUNPRO_C) || defined(__llvm__)
#  define ECB_GCC_VERSION(major,minor) 0
# else
#  define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
# endif
#endif

#ifndef __cplusplus
# if __STDC_VERSION__ >= 199901L
#  define ECB_INLINE inline
typedef _Bool ecb_bool;
# else
#  define ECB_INLINE inline /* yeah! */
typedef int ecb_bool;
# endif
#endif

#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_HEADER_INLINE static ECB_INLINE

#if ECB_GCC_VERSION(3,1)
# define ecb_attribute(attrlist)        __attribute__(attrlist)
# define ecb_is_constant(c)             __builtin_constant_p (c)
# 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(c)             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))
#define ecb_hot      ecb_attribute ((hot))      /* 4.3 */
#define ecb_cold     ecb_attribute ((cold))     /* 4.3 */

/* put into ifs if you are very sure that the expression */
/* is mostly true or mosty false. note that these return */
/* booleans, not the expression. */
#define ecb_unlikely(expr) ecb_expect (!!(expr), 0)
#define ecb_likely(expr)   ecb_expect (!!(expr), 1)

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

/* count trailing zero bits and count # of one bits */
ECB_HEADER_INLINE int ecb_ctz32      (uint32_t x) ecb_const;
ECB_HEADER_INLINE int ecb_popcount32 (uint32_t x) ecb_const;
#if ECB_GCC_VERSION(3,4)
ECB_HEADER_INLINE int ecb_ctz32      (uint32_t x) { return __builtin_ctz      (x); }
ECB_HEADER_INLINE int ecb_popcount32 (uint32_t x) { return __builtin_popcount (x); }
#else
ECB_HEADER_INLINE
ecb_ctz32 (uint32_t x)
{
  int r = 0;

  x &= -x; /* 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_HEADER_INLINE
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;
}
#endif

ECB_HEADER_INLINE uint32_t ecb_bswap32 (uint32_t x) ecb_const;
#if ECB_GCC_VERSION(4,3)
ECB_HEADER_INLINE uint32_t ecb_bswap32 (uint32_t x) { return __builtin_bswap32 (x); }
#else
ECB_HEADER_INLINE uint32_t
ecb_bswap32 (uint32_t x)
{
  return (x >> 24)
      | ((x >>  8) & 0x0000ff00)
      | ((x <<  8) & 0x00ff0000)
      |  (x << 24);
}
#endif

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

ECB_HEADER_INLINE unsigned char ecb_byteorder_helper () ecb_const;

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

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

#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);
}

#endif

Revision:	1.15
Committed:	Thu May 26 18:31:02 2011 UTC (12 years, 11 months ago) by sf-exg
Content type:	text/plain
Branch:	MAIN
Changes since 1.14:	+1 -1 lines
Log Message:	Simplify.
#	Content
1	/*
2	* libecb
3	*
4	* Copyright (©) 2009-2011 Marc Alexander Lehmann
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	#include <inttypes.h>
34
35	/* many compilers define _GNUC_ to some versions but then only implement
36	* what their idiot authors think are the "more important" extensions,
37	* causing enourmous grief for some better fake benchmark numbers or so.
38	* we try to detect these and simply assume they are not gcc - if they have
39	* an issue with that they should have done it right in the first place.
40	*/
41	#ifndef ECB_GCC_VERSION
42	# if defined(__INTEL_COMPILER) \|\| defined(__SUNPRO_C) \|\| defined(__llvm__)
43	# define ECB_GCC_VERSION(major,minor) 0
44	# else
45	# define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) \|\| (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
46	# endif
47	#endif
48
49	#ifndef __cplusplus
50	# if __STDC_VERSION__ >= 199901L
51	# define ECB_INLINE inline
52	typedef _Bool ecb_bool;
53	# else
54	# define ECB_INLINE inline /* yeah! */
55	typedef int ecb_bool;
56	# endif
57	#endif
58
59	#define ECB_CONCAT_(a, b) a ## b
60	#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
61	#define ECB_STRINGIFY_(a) # a
62	#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)
63
64	#define ECB_HEADER_INLINE static ECB_INLINE
65
66	#if ECB_GCC_VERSION(3,1)
67	# define ecb_attribute(attrlist) __attribute__(attrlist)
68	# define ecb_is_constant(c) __builtin_constant_p (c)
69	# define ecb_expect(expr,value) __builtin_expect ((expr),(value))
70	# define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
71	#else
72	# define ecb_attribute(attrlist)
73	# define ecb_is_constant(c) 0
74	# define ecb_expect(expr,value) (expr)
75	# define ecb_prefetch(addr,rw,locality)
76	#endif
77
78	/* no emulation for ecb_decltype */
79	#if ECB_GCC_VERSION(4,5)
80	# define ecb_decltype(x) __decltype(x)
81	#elif ECB_GCC_VERSION(3,0)
82	# define ecb_decltype(x) typeof(x)
83	#endif
84
85	#define ecb_noinline ecb_attribute ((noinline))
86	#define ecb_noreturn ecb_attribute ((noreturn))
87	#define ecb_unused ecb_attribute ((unused))
88	#define ecb_const ecb_attribute ((const))
89	#define ecb_pure ecb_attribute ((pure))
90	#define ecb_hot ecb_attribute ((hot)) /* 4.3 */
91	#define ecb_cold ecb_attribute ((cold)) /* 4.3 */
92
93	/* put into ifs if you are very sure that the expression */
94	/* is mostly true or mosty false. note that these return */
95	/* booleans, not the expression. */
96	#define ecb_unlikely(expr) ecb_expect (!!(expr), 0)
97	#define ecb_likely(expr) ecb_expect (!!(expr), 1)
98
99	/* try to tell the compiler that some condition is definitely true */
100	#define ecb_assume(cond) do { if (!(cond)) unreachable (); } while (0)
101
102	/* count trailing zero bits and count # of one bits */
103	ECB_HEADER_INLINE int ecb_ctz32 (uint32_t x) ecb_const;
104	ECB_HEADER_INLINE int ecb_popcount32 (uint32_t x) ecb_const;
105	#if ECB_GCC_VERSION(3,4)
106	ECB_HEADER_INLINE int ecb_ctz32 (uint32_t x) { return __builtin_ctz (x); }
107	ECB_HEADER_INLINE int ecb_popcount32 (uint32_t x) { return __builtin_popcount (x); }
108	#else
109	ECB_HEADER_INLINE
110	ecb_ctz32 (uint32_t x)
111	{
112	int r = 0;
113
114	x &= -x; /* this isolates the lowest bit */
115
116	if (x & 0xaaaaaaaa) r += 1;
117	if (x & 0xcccccccc) r += 2;
118	if (x & 0xf0f0f0f0) r += 4;
119	if (x & 0xff00ff00) r += 8;
120	if (x & 0xffff0000) r += 16;
121
122	return r;
123	}
124
125	ECB_HEADER_INLINE
126	ecb_popcount32 (uint32_t x)
127	{
128	x -= (x >> 1) & 0x55555555;
129	x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
130	x = ((x >> 4) + x) & 0x0f0f0f0f;
131	x *= 0x01010101;
132
133	return x >> 24;
134	}
135	#endif
136
137	ECB_HEADER_INLINE uint32_t ecb_bswap32 (uint32_t x) ecb_const;
138	#if ECB_GCC_VERSION(4,3)
139	ECB_HEADER_INLINE uint32_t ecb_bswap32 (uint32_t x) { return __builtin_bswap32 (x); }
140	#else
141	ECB_HEADER_INLINE uint32_t
142	ecb_bswap32 (uint32_t x)
143	{
144	return (x >> 24)
145	\| ((x >> 8) & 0x0000ff00)
146	\| ((x << 8) & 0x00ff0000)
147	\| (x << 24);
148	}
149	#endif
150
151	ECB_HEADER_INLINE void ecb_unreachable (void) ecb_noreturn;
152	#if ECB_GCC_VERSION(4,5)
153	ECB_HEADER_INLINE void ecb_unreachable (void) { __builtin_unreachable (); }
154	#else
155	/* this seems to work fine, but gcc always emits a warning for it :/ */
156	ECB_HEADER_INLINE void ecb_unreachable (void) { }
157	#endif
158
159	ECB_HEADER_INLINE unsigned char ecb_byteorder_helper () ecb_const;
160
161	ECB_HEADER_INLINE unsigned char
162	ecb_byteorder_helper ()
163	{
164	const uint32_t u = 0x11223344;
165	return (unsigned char )&u;
166	}
167
168	ECB_HEADER_INLINE ecb_bool ecb_big_endian () ecb_const;
169	ECB_HEADER_INLINE ecb_bool ecb_big_endian () { return ecb_byteorder_helper () == 0x11; };
170	ECB_HEADER_INLINE ecb_bool ecb_little_endian () ecb_const;
171	ECB_HEADER_INLINE ecb_bool ecb_little_endian () { return ecb_byteorder_helper () == 0x44; };
172
173	#if ecb_cplusplus_does_not_suck
174	// does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm)
175	template<typename T, int N>
176	static inline int ecb_array_length (const T (&arr)[N])
177	{
178	return N;
179	}
180	#else
181	#define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
182	#endif
183
184	ECB_INLINE uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
185	ECB_INLINE uint32_t
186	ecb_rotr32 (uint32_t x, unsigned int count)
187	{
188	return (x << (32 - count)) \| (x >> count);
189	}
190
191	ECB_INLINE uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
192	ECB_INLINE uint32_t
193	ecb_rotl32 (uint32_t x, unsigned int count)
194	{
195	return (x >> (32 - count)) \| (x << count);
196	}
197
198	#endif
199