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29 | #ifndef ECB_H |
29 | #ifndef ECB_H |
30 | #define ECB_H |
30 | #define ECB_H |
31 | |
31 | |
32 | #define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor))) |
32 | #define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor))) |
33 | |
33 | |
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34 | #ifndef __cplusplus |
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35 | # if __STDC_VERSION__ >= 199901L |
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36 | # define ECB_INLINE inline |
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37 | typedef _Bool ecb_bool; |
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38 | # else |
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39 | # define ECB_INLINE inline /* yeah! */ |
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40 | typedef int ecb_bool; |
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41 | # endif |
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42 | #endif |
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43 | |
34 | #define ECB_HEADER_INLINE static inline |
44 | #define ECB_HEADER_INLINE static ECB_INLINE |
35 | |
45 | |
36 | #if ECB_GCC_VERSION(3,1) |
46 | #if ECB_GCC_VERSION(3,1) |
37 | # define ecb_attribute(attrlist) __attribute__(attrlist) |
47 | # define ecb_attribute(attrlist) __attribute__(attrlist) |
38 | # define ecb_is_constant(c) __builtin_constant_p (c) |
48 | # define ecb_is_constant(c) __builtin_constant_p (c) |
39 | # define ecb_expect(expr,value) __builtin_expect ((expr),(value)) |
49 | # define ecb_expect(expr,value) __builtin_expect ((expr),(value)) |
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55 | #define ecb_noinline ecb_attribute ((noinline)) |
65 | #define ecb_noinline ecb_attribute ((noinline)) |
56 | #define ecb_noreturn ecb_attribute ((noreturn)) |
66 | #define ecb_noreturn ecb_attribute ((noreturn)) |
57 | #define ecb_unused ecb_attribute ((unused)) |
67 | #define ecb_unused ecb_attribute ((unused)) |
58 | #define ecb_const ecb_attribute ((const)) |
68 | #define ecb_const ecb_attribute ((const)) |
59 | #define ecb_pure ecb_attribute ((pure)) |
69 | #define ecb_pure ecb_attribute ((pure)) |
60 | #define ecb_hot ecb_attribute ((hot)) // 4.3 |
70 | #define ecb_hot ecb_attribute ((hot)) /* 4.3 */ |
61 | #define ecb_cold ecb_attribute ((cold)) // 4.3 |
71 | #define ecb_cold ecb_attribute ((cold)) /* 4.3 */ |
62 | |
72 | |
63 | #if ECB_GCC_VERSION(4,5) |
73 | #if ECB_GCC_VERSION(4,5) |
64 | # define ecb_unreachable() __builtin_unreachable () |
74 | # define ecb_unreachable() __builtin_unreachable () |
65 | #else |
75 | #else |
66 | /* this seems to work fine, but gcc always emits a warning for it :/ */ |
76 | /* this seems to work fine, but gcc always emits a warning for it :/ */ |
67 | ECB_HEADER_INLINE void ecb_unreachable () ecb_attribute ((noreturn)); |
77 | ECB_HEADER_INLINE void ecb_unreachable () ecb_attribute ((noreturn)); |
68 | ECB_HEADER_INLINE void ecb_unreachable () { } |
78 | ECB_HEADER_INLINE void ecb_unreachable () { } |
69 | #endif |
79 | #endif |
70 | |
80 | |
71 | /* put into ifs if you are very sure that the expression */ |
81 | /* put into ifs if you are very sure that the expression */ |
72 | /* is mostly true or mosty false. note that these return */ |
82 | /* is mostly true or mosty false. note that these return */ |
73 | /* booleans, not the expression. */ |
83 | /* booleans, not the expression. */ |
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77 | /* try to tell the compiler that some condition is definitely true */ |
87 | /* try to tell the compiler that some condition is definitely true */ |
78 | #define ecb_assume(cond) do { if (!(cond)) unreachable (); } while (0) |
88 | #define ecb_assume(cond) do { if (!(cond)) unreachable (); } while (0) |
79 | |
89 | |
80 | /* count trailing zero bits and count # of one bits */ |
90 | /* count trailing zero bits and count # of one bits */ |
81 | #if ECB_GCC_VERSION(3,4) |
91 | #if ECB_GCC_VERSION(3,4) |
82 | ECB_HEADER_INLINE int ecb_ctz (unsigned int x) { return __builtin_ctz (x); } |
92 | ECB_HEADER_INLINE int ecb_ctz32 (unsigned int x) { return __builtin_ctz (x); } |
83 | ECB_HEADER_INLINE int ecb_popcount (unsigned int x) { return __builtin_popcount (x); } |
93 | ECB_HEADER_INLINE int ecb_popcount32 (unsigned int x) { return __builtin_popcount (x); } |
84 | #else |
94 | #else |
85 | ECB_HEADER_INLINE |
95 | ECB_HEADER_INLINE |
86 | ecb_ctz (unsigned int x) ecb_const |
96 | ecb_ctz32 (unsigned int x) ecb_const |
87 | { |
97 | { |
88 | int r = 0; |
98 | int r = 0; |
89 | |
99 | |
90 | x &= -x; // this isolates the lowest bit |
100 | x &= -x; /* this isolates the lowest bit */ |
91 | |
101 | |
92 | if (x & 0xaaaaaaaa) r += 1; |
102 | if (x & 0xaaaaaaaa) r += 1; |
93 | if (x & 0xcccccccc) r += 2; |
103 | if (x & 0xcccccccc) r += 2; |
94 | if (x & 0xf0f0f0f0) r += 4; |
104 | if (x & 0xf0f0f0f0) r += 4; |
95 | if (x & 0xff00ff00) r += 8; |
105 | if (x & 0xff00ff00) r += 8; |
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97 | |
107 | |
98 | return r; |
108 | return r; |
99 | } |
109 | } |
100 | |
110 | |
101 | ECB_HEADER_INLINE |
111 | ECB_HEADER_INLINE |
102 | ecb_popcount (unsigned int x) ecb_const |
112 | ecb_popcount32 (unsigned int x) ecb_const |
103 | { |
113 | { |
104 | x -= (x >> 1) & 0x55555555; |
114 | x -= (x >> 1) & 0x55555555; |
105 | x = ((x >> 2) & 0x33333333) + (x & 0x33333333); |
115 | x = ((x >> 2) & 0x33333333) + (x & 0x33333333); |
106 | x = ((x >> 4) + x) & 0x0f0f0f0f; |
116 | x = ((x >> 4) + x) & 0x0f0f0f0f; |
107 | x *= 0x01010101; |
117 | x *= 0x01010101; |
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115 | { |
125 | { |
116 | const uint32_t u = 0x11223344; |
126 | const uint32_t u = 0x11223344; |
117 | return *(unsigned char *)&u; |
127 | return *(unsigned char *)&u; |
118 | } |
128 | } |
119 | |
129 | |
120 | ECB_HEADER_INLINE bool ecb_big_endian () ecb_const { return ecb_byteorder_helper () == 0x11; }; |
130 | ECB_HEADER_INLINE ecb_bool ecb_big_endian () ecb_const { return ecb_byteorder_helper () == 0x11; }; |
121 | ECB_HEADER_INLINE bool ecb_network () ecb_const { return big_endian (); }; |
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122 | ECB_HEADER_INLINE bool ecb_little_endian () ecb_const { return ecb_byteorder_helper () == 0x44; }; |
131 | ECB_HEADER_INLINE ecb_bool ecb_little_endian () ecb_const { return ecb_byteorder_helper () == 0x44; }; |
123 | ECB_HEADER_INLINE bool ecb_vax () ecb_const { return little_endian (); }; |
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132 | |
126 | #endif |
133 | #endif |
127 | |
134 | |