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

#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 static inline
typedef _Bool ecb_bool;
# else
#  define ECB_INLINE static inline /* yeah! */
typedef int ecb_bool;
# endif
#else
# define ECB_INLINE static inline
typedef bool ecb_bool;
#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 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_artificial ecb_attribute ((__artificial__)) /* 4.3 */
#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 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)
#define ecb_likely(expr)   ecb_expect_true  (expr)
#define ecb_unlikely(expr) ecb_expect_false (expr)

/* 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 int
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 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;
}
#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; };

#if ECB_GCC_VERSION(3,0)
# 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);
}

#endif

Revision:	1.1
Committed:	Fri Jun 10 12:35:18 2011 UTC (12 years, 11 months ago) by root
Content type:	text/plain
Branch:	MAIN
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	#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 in return for some better fake benchmark numbers.
38	* or so.
39	* 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	#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	#endif
49
50	#ifndef __cplusplus
51	# if __STDC_VERSION__ >= 199901L
52	# define ECB_INLINE static inline
53	typedef _Bool ecb_bool;
54	# else
55	# define ECB_INLINE static inline /* yeah! */
56	typedef int ecb_bool;
57	# endif
58	#else
59	# define ECB_INLINE static inline
60	typedef bool ecb_bool;
61	#endif
62
63	#define ECB_CONCAT_(a, b) a ## b
64	#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
65	#define ECB_STRINGIFY_(a) # a
66	#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)
67
68	#define ECB_HEADER_INLINE ECB_INLINE
69
70	#if ECB_GCC_VERSION(3,1)
71	# define ecb_attribute(attrlist) __attribute__(attrlist)
72	# define ecb_is_constant(expr) __builtin_constant_p (expr)
73	# define ecb_expect(expr,value) __builtin_expect ((expr),(value))
74	# define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
75	#else
76	# define ecb_attribute(attrlist)
77	# define ecb_is_constant(expr) 0
78	# define ecb_expect(expr,value) (expr)
79	# define ecb_prefetch(addr,rw,locality)
80	#endif
81
82	/* no emulation for ecb_decltype */
83	#if ECB_GCC_VERSION(4,5)
84	# define ecb_decltype(x) __decltype(x)
85	#elif ECB_GCC_VERSION(3,0)
86	# define ecb_decltype(x) typeof(x)
87	#endif
88
89	#define ecb_artificial ecb_attribute ((__artificial__)) /* 4.3 */
90	#define ecb_noinline ecb_attribute ((__noinline__))
91	#define ecb_noreturn ecb_attribute ((__noreturn__))
92	#define ecb_unused ecb_attribute ((__unused__))
93	#define ecb_const ecb_attribute ((__const__))
94	#define ecb_pure ecb_attribute ((__pure__))
95	#define ecb_hot ecb_attribute ((__hot__)) /* 4.3 */
96	#define ecb_cold ecb_attribute ((__cold__)) /* 4.3 */
97
98	/* put into if's if you are very sure that the expression */
99	/* is mostly true or mostly false. note that these return */
100	/* booleans, not the expression. */
101	#define ecb_expect_false(expr) ecb_expect (!!(expr), 0)
102	#define ecb_expect_true(expr) ecb_expect (!!(expr), 1)
103	#define ecb_likely(expr) ecb_expect_true (expr)
104	#define ecb_unlikely(expr) ecb_expect_false (expr)
105
106	/* try to tell the compiler that some condition is definitely true */
107	#define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0)
108
109	/* count trailing zero bits and count # of one bits */
110	#if ECB_GCC_VERSION(3,4)
111	#define ecb_ctz32(x) __builtin_ctz (x)
112	#define ecb_popcount32(x) __builtin_popcount (x)
113	#else
114	ECB_HEADER_INLINE int ecb_ctz32 (uint32_t x) ecb_const;
115	ECB_HEADER_INLINE int
116	ecb_ctz32 (uint32_t x)
117	{
118	int r = 0;
119
120	x &= -x; /* this isolates the lowest bit */
121
122	if (x & 0xaaaaaaaa) r += 1;
123	if (x & 0xcccccccc) r += 2;
124	if (x & 0xf0f0f0f0) r += 4;
125	if (x & 0xff00ff00) r += 8;
126	if (x & 0xffff0000) r += 16;
127
128	return r;
129	}
130
131	ECB_HEADER_INLINE int ecb_popcount32 (uint32_t x) ecb_const;
132	ECB_HEADER_INLINE int
133	ecb_popcount32 (uint32_t x)
134	{
135	x -= (x >> 1) & 0x55555555;
136	x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
137	x = ((x >> 4) + x) & 0x0f0f0f0f;
138	x *= 0x01010101;
139
140	return x >> 24;
141	}
142	#endif
143
144	#if ECB_GCC_VERSION(4,3)
145	# define ecb_bswap32(x) __builtin_bswap32 (x)
146	# define ecb_bswap16(x) (__builtin_bswap32(x) >> 16)
147	#else
148	ECB_HEADER_INLINE uint32_t ecb_bswap32 (uint32_t x) ecb_const;
149	ECB_HEADER_INLINE uint32_t
150	ecb_bswap32 (uint32_t x)
151	{
152	return (x >> 24)
153	\| ((x >> 8) & 0x0000ff00)
154	\| ((x << 8) & 0x00ff0000)
155	\| (x << 24);
156	}
157
158	ECB_HEADER_INLINE uint32_t ecb_bswap16 (uint32_t x) ecb_const;
159	ECB_HEADER_INLINE uint32_t
160	ecb_bswap16 (uint32_t x)
161	{
162	return ((x >> 8) & 0xff)
163	\| ((x << 8) & 0x00ff0000)
164	\| (x << 24);
165	}
166	#endif
167
168	#if ECB_GCC_VERSION(4,5)
169	# define ecb_unreachable() __builtin_unreachable ()
170	#else
171	/* this seems to work fine, but gcc always emits a warning for it :/ */
172	ECB_HEADER_INLINE void ecb_unreachable (void) ecb_noreturn;
173	ECB_HEADER_INLINE void ecb_unreachable (void) { }
174	#endif
175
176	ECB_HEADER_INLINE unsigned char ecb_byteorder_helper (void) ecb_const;
177	ECB_HEADER_INLINE unsigned char
178	ecb_byteorder_helper (void)
179	{
180	const uint32_t u = 0x11223344;
181	return (unsigned char )&u;
182	}
183
184	ECB_HEADER_INLINE ecb_bool ecb_big_endian (void) ecb_const;
185	ECB_HEADER_INLINE ecb_bool ecb_big_endian (void) { return ecb_byteorder_helper () == 0x11; };
186	ECB_HEADER_INLINE ecb_bool ecb_little_endian (void) ecb_const;
187	ECB_HEADER_INLINE ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44; };
188
189	#if ECB_GCC_VERSION(3,0)
190	# define ecb_mod(m,n) ((m) % (n) + ((m) % (n) < 0 ? (n) : 0))
191	#else
192	# define ecb_mod(m,n) ((m) < 0 ? ((n) - 1 - ((-1 - (m)) % (n))) : ((m) % (n)))
193	#endif
194
195	#if ecb_cplusplus_does_not_suck
196	// does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm)
197	template<typename T, int N>
198	static inline int ecb_array_length (const T (&arr)[N])
199	{
200	return N;
201	}
202	#else
203	#define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
204	#endif
205
206	ECB_INLINE uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
207	ECB_INLINE uint32_t
208	ecb_rotr32 (uint32_t x, unsigned int count)
209	{
210	return (x << (32 - count)) \| (x >> count);
211	}
212
213	ECB_INLINE uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
214	ECB_INLINE uint32_t
215	ecb_rotl32 (uint32_t x, unsigned int count)
216	{
217	return (x >> (32 - count)) \| (x << count);
218	}
219
220	#endif
221