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/cvs/libecb/ecb.h
Revision: 1.23
Committed: Thu May 26 19:40:09 2011 UTC (13 years ago) by root
Content type: text/plain
Branch: MAIN
Changes since 1.22: +6 -6 lines
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# Content
1 /*
2 * libecb - http://software.schmorp.de/pkg/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 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 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 #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 #define ECB_HEADER_INLINE static ECB_INLINE
66
67 #if ECB_GCC_VERSION(3,1)
68 # define ecb_attribute(attrlist) __attribute__(attrlist)
69 # define ecb_is_constant(expr) __builtin_constant_p (expr)
70 # 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 # define ecb_is_constant(expr) 0
75 # define ecb_expect(expr,value) (expr)
76 # define ecb_prefetch(addr,rw,locality)
77 #endif
78
79 /* no emulation for ecb_decltype */
80 #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 #define ecb_hot ecb_attribute ((hot)) /* 4.3 */
92 #define ecb_cold ecb_attribute ((cold)) /* 4.3 */
93
94 /* put into if's if you are very sure that the expression */
95 /* is mostly true or mosty false. note that these return */
96 /* booleans, not the expression. */
97 #define ecb_unlikely(expr) ecb_expect (!!(expr), 0)
98 #define ecb_likely(expr) ecb_expect (!!(expr), 1)
99
100 /* try to tell the compiler that some condition is definitely true */
101 #define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0)
102
103 /* count trailing zero bits and count # of one bits */
104 #if ECB_GCC_VERSION(3,4)
105 #define ecb_ctz32 (x) __builtin_ctz (x)
106 #define ecb_popcount32 (x) __builtin_popcount (x)
107 #else
108 ECB_HEADER_INLINE int ecb_ctz32 (uint32_t x) ecb_const;
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 int ecb_popcount32 (uint32_t x) ecb_const;
126 ECB_HEADER_INLINE
127 ecb_popcount32 (uint32_t x)
128 {
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 #if ECB_GCC_VERSION(4,3)
139 # define ecb_bswap32(x) __builtin_bswap32 (x)
140 # define ecb_bswap16(x) (__builtin_bswap32(x) >> 16)
141 #else
142 ECB_HEADER_INLINE uint32_t ecb_bswap32 (uint32_t x) ecb_const;
143 ECB_HEADER_INLINE uint32_t
144 ecb_bswap32 (uint32_t x)
145 {
146 return (x >> 24)
147 | ((x >> 8) & 0x0000ff00)
148 | ((x << 8) & 0x00ff0000)
149 | (x << 24);
150 }
151
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 #endif
161
162 #if ECB_GCC_VERSION(4,5)
163 # define ecb_unreachable() __builtin_unreachable ()
164 #else
165 /* this seems to work fine, but gcc always emits a warning for it :/ */
166 ECB_HEADER_INLINE void ecb_unreachable (void) ecb_noreturn;
167 ECB_HEADER_INLINE void ecb_unreachable (void) { }
168 #endif
169
170 ECB_HEADER_INLINE unsigned char ecb_byteorder_helper (void) ecb_const;
171 ECB_HEADER_INLINE unsigned char
172 ecb_byteorder_helper (void)
173 {
174 const uint32_t u = 0x11223344;
175 return *(unsigned char *)&u;
176 }
177
178 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
183 #define ecb_mod(m, n) ((m) < 0 ? ((n) - (-(m) % (n))) : ((m) % (n)))
184
185 #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 static inline int ecb_array_length (const T (&arr)[N])
189 {
190 return N;
191 }
192 #else
193 #define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
194 #endif
195
196 ECB_INLINE uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
197 ECB_INLINE uint32_t
198 ecb_rotr32 (uint32_t x, unsigned int count)
199 {
200 return (x << (32 - count)) | (x >> count);
201 }
202
203 ECB_INLINE uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
204 ECB_INLINE uint32_t
205 ecb_rotl32 (uint32_t x, unsigned int count)
206 {
207 return (x >> (32 - count)) | (x << count);
208 }
209
210 #endif
211