libecb/ecb.h

/*
 * libecb - http://software.schmorp.de/pkg/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 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(__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(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))
#define ecb_hot      ecb_attribute ((hot))      /* 4.3 */
#define ecb_cold     ecb_attribute ((cold))     /* 4.3 */

/* put into if's 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)) ecb_unreachable (); } while (0)

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

#if ECB_GCC_VERSION(4,3)
# define ecb_bswap32(x) __builtin_bswap32 (x)
# define ecb_bswap16(x) (__builtin_bswap32(x) >> 16)
#else
ECB_HEADER_INLINE uint32_t ecb_bswap32 (uint32_t x) ecb_const;
ECB_HEADER_INLINE uint32_t
ecb_bswap32 (uint32_t x)
{
  return (x >> 24)
      | ((x >>  8) & 0x0000ff00)
      | ((x <<  8) & 0x00ff0000)
      |  (x << 24);
}

ECB_HEADER_INLINE uint32_t ecb_bswap16 (uint32_t x) ecb_const;
ECB_HEADER_INLINE uint32_t
ecb_bswap16 (uint32_t x)
{
  return ((x >>  8) & 0xff)
      |  ((x <<  8) & 0x00ff0000)
      |  (x << 24);
}
#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_HEADER_INLINE void ecb_unreachable (void) ecb_noreturn;
ECB_HEADER_INLINE void ecb_unreachable (void) { }
#endif

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

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

#define ecb_mod(m, n) ((m) < 0 ? ((n) - (-(m) % (n))) : ((m) % (n)))

#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:	1.23
Committed:	Thu May 26 19:40:09 2011 UTC (12 years, 11 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.22:	+6 -6 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/*
2	root	1.17	* libecb - http://software.schmorp.de/pkg/libecb
3	root	1.1	*
4	root	1.2	* Copyright (©) 2009-2011 Marc Alexander Lehmann
5	root	1.7	* Copyright (©) 2011 Emanuele Giaquinta
6	root	1.1	* 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	1.6	#include <inttypes.h>
34
35	root	1.12	/* many compilers define _GNUC_ to some versions but then only implement
36			* what their idiot authors think are the "more important" extensions,
37	root	1.18	* causing enourmous grief in return for some better fake benchmark numbers.
38			* or so.
39	root	1.12	* we try to detect these and simply assume they are not gcc - if they have
40			* an issue with that they should have done it right in the first place.
41			*/
42	root	1.14	#ifndef ECB_GCC_VERSION
43			# if defined(__INTEL_COMPILER) \|\| defined(__SUNPRO_C) \|\| defined(__llvm__)
44			# define ECB_GCC_VERSION(major,minor) 0
45			# else
46			# define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) \|\| (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
47			# endif
48	root	1.12	#endif
49	root	1.1
50	root	1.4	#ifndef __cplusplus
51			# if __STDC_VERSION__ >= 199901L
52			# define ECB_INLINE inline
53			typedef _Bool ecb_bool;
54			# else
55			# define ECB_INLINE inline /* yeah! */
56			typedef int ecb_bool;
57			# endif
58			#endif
59
60	root	1.8	#define ECB_CONCAT_(a, b) a ## b
61			#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
62			#define ECB_STRINGIFY_(a) # a
63			#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)
64
65	root	1.4	#define ECB_HEADER_INLINE static ECB_INLINE
66	root	1.3
67	root	1.1	#if ECB_GCC_VERSION(3,1)
68			# define ecb_attribute(attrlist) __attribute__(attrlist)
69	root	1.22	# define ecb_is_constant(expr) __builtin_constant_p (expr)
70	root	1.1	# define ecb_expect(expr,value) __builtin_expect ((expr),(value))
71			# define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
72			#else
73			# define ecb_attribute(attrlist)
74	root	1.22	# define ecb_is_constant(expr) 0
75	root	1.1	# define ecb_expect(expr,value) (expr)
76			# define ecb_prefetch(addr,rw,locality)
77			#endif
78
79	root	1.2	/* no emulation for ecb_decltype */
80	root	1.1	#if ECB_GCC_VERSION(4,5)
81			# define ecb_decltype(x) __decltype(x)
82			#elif ECB_GCC_VERSION(3,0)
83			# define ecb_decltype(x) typeof(x)
84			#endif
85
86			#define ecb_noinline ecb_attribute ((noinline))
87			#define ecb_noreturn ecb_attribute ((noreturn))
88			#define ecb_unused ecb_attribute ((unused))
89			#define ecb_const ecb_attribute ((const))
90			#define ecb_pure ecb_attribute ((pure))
91	root	1.4	#define ecb_hot ecb_attribute ((hot)) /* 4.3 */
92			#define ecb_cold ecb_attribute ((cold)) /* 4.3 */
93	root	1.1
94	root	1.22	/* put into if's if you are very sure that the expression */
95	root	1.3	/* is mostly true or mosty false. note that these return */
96			/* booleans, not the expression. */
97	root	1.11	#define ecb_unlikely(expr) ecb_expect (!!(expr), 0)
98			#define ecb_likely(expr) ecb_expect (!!(expr), 1)
99	root	1.1
100	root	1.3	/* try to tell the compiler that some condition is definitely true */
101	root	1.19	#define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0)
102	root	1.1
103	root	1.3	/* count trailing zero bits and count # of one bits */
104	root	1.1	#if ECB_GCC_VERSION(3,4)
105	root	1.16	#define ecb_ctz32 (x) __builtin_ctz (x)
106			#define ecb_popcount32 (x) __builtin_popcount (x)
107	root	1.1	#else
108	root	1.19	ECB_HEADER_INLINE int ecb_ctz32 (uint32_t x) ecb_const;
109	root	1.3	ECB_HEADER_INLINE
110	root	1.14	ecb_ctz32 (uint32_t x)
111	root	1.1	{
112			int r = 0;
113
114	root	1.4	x &= -x; /* this isolates the lowest bit */
115	root	1.1
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	root	1.16	ECB_HEADER_INLINE int ecb_popcount32 (uint32_t x) ecb_const;
126	root	1.3	ECB_HEADER_INLINE
127	root	1.14	ecb_popcount32 (uint32_t x)
128	root	1.1	{
129			x -= (x >> 1) & 0x55555555;
130			x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
131			x = ((x >> 4) + x) & 0x0f0f0f0f;
132			x *= 0x01010101;
133
134			return x >> 24;
135			}
136			#endif
137
138	root	1.13	#if ECB_GCC_VERSION(4,3)
139	root	1.16	# define ecb_bswap32(x) __builtin_bswap32 (x)
140	root	1.20	# define ecb_bswap16(x) (__builtin_bswap32(x) >> 16)
141	root	1.13	#else
142	root	1.16	ECB_HEADER_INLINE uint32_t ecb_bswap32 (uint32_t x) ecb_const;
143	root	1.14	ECB_HEADER_INLINE uint32_t
144	root	1.13	ecb_bswap32 (uint32_t x)
145			{
146			return (x >> 24)
147			\| ((x >> 8) & 0x0000ff00)
148			\| ((x << 8) & 0x00ff0000)
149			\| (x << 24);
150			}
151	root	1.20
152			ECB_HEADER_INLINE uint32_t ecb_bswap16 (uint32_t x) ecb_const;
153			ECB_HEADER_INLINE uint32_t
154			ecb_bswap16 (uint32_t x)
155			{
156			return ((x >> 8) & 0xff)
157			\| ((x << 8) & 0x00ff0000)
158			\| (x << 24);
159			}
160	root	1.13	#endif
161
162			#if ECB_GCC_VERSION(4,5)
163	root	1.16	# define ecb_unreachable() __builtin_unreachable ()
164	root	1.13	#else
165			/* this seems to work fine, but gcc always emits a warning for it :/ */
166	root	1.17	ECB_HEADER_INLINE void ecb_unreachable (void) ecb_noreturn;
167	root	1.14	ECB_HEADER_INLINE void ecb_unreachable (void) { }
168	root	1.13	#endif
169
170	root	1.23	ECB_HEADER_INLINE unsigned char ecb_byteorder_helper (void) ecb_const;
171	root	1.3	ECB_HEADER_INLINE unsigned char
172	root	1.23	ecb_byteorder_helper (void)
173	root	1.3	{
174			const uint32_t u = 0x11223344;
175			return (unsigned char )&u;
176			}
177
178	root	1.23	ECB_HEADER_INLINE ecb_bool ecb_big_endian (void) ecb_const;
179			ECB_HEADER_INLINE ecb_bool ecb_big_endian (void) { return ecb_byteorder_helper () == 0x11; };
180			ECB_HEADER_INLINE ecb_bool ecb_little_endian (void) ecb_const;
181			ECB_HEADER_INLINE ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44; };
182	root	1.3
183	root	1.21	#define ecb_mod(m, n) ((m) < 0 ? ((n) - (-(m) % (n))) : ((m) % (n)))
184
185	root	1.5	#if ecb_cplusplus_does_not_suck
186			// does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm)
187			template<typename T, int N>
188	root	1.8	static inline int ecb_array_length (const T (&arr)[N])
189	root	1.5	{
190			return N;
191			}
192			#else
193			#define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
194			#endif
195
196	root	1.14	ECB_INLINE uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
197	root	1.6	ECB_INLINE uint32_t
198	root	1.9	ecb_rotr32 (uint32_t x, unsigned int count)
199	root	1.6	{
200	root	1.9	return (x << (32 - count)) \| (x >> count);
201	root	1.6	}
202
203	root	1.14	ECB_INLINE uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
204	root	1.6	ECB_INLINE uint32_t
205	root	1.9	ecb_rotl32 (uint32_t x, unsigned int count)
206	root	1.6	{
207	root	1.9	return (x >> (32 - count)) \| (x << count);
208	root	1.6	}
209
210	root	1.1	#endif
211