source: trunk/src/kmk/inlined_memchr.h@ 2045

Last change on this file since 2045 was 1822, checked in by bird, 17 years ago

inlined_memchr: hacked up a 8-byte loop unroll, doesn't by much/anything over the four byte one though so it's disabled.
  • Property svn:eol-style set to native
  • Property svn:keywords set to Id
File size: 4.5 KB
Line 
1#include <string.h>
2
3#ifdef _MSC_VER
4_inline void *
5#else
6static __inline__ void *
7#endif
8my_inline_memchr(const void *pv, int ch, register size_t cb)
9{
10 register const unsigned int uch = (unsigned)ch;
11 register const unsigned char *pb = (const unsigned char *)pv;
12#if 0 /* 8-byte loop unroll */
13 while (cb >= 8)
14 {
15 if (*pb == uch)
16 return (unsigned char *)pb;
17 if (pb[1] == uch)
18 return (unsigned char *)pb + 1;
19 if (pb[2] == uch)
20 return (unsigned char *)pb + 2;
21 if (pb[3] == uch)
22 return (unsigned char *)pb + 3;
23 if (pb[4] == uch)
24 return (unsigned char *)pb + 4;
25 if (pb[5] == uch)
26 return (unsigned char *)pb + 5;
27 if (pb[6] == uch)
28 return (unsigned char *)pb + 6;
29 if (pb[7] == uch)
30 return (unsigned char *)pb + 7;
31 cb -= 8;
32 pb += 8;
33 }
34 switch (cb & 7)
35 {
36 case 0:
37 break;
38 case 1:
39 if (*pb == uch)
40 return (unsigned char *)pb;
41 break;
42 case 2:
43 if (*pb == uch)
44 return (unsigned char *)pb;
45 if (pb[1] == uch)
46 return (unsigned char *)pb + 1;
47 break;
48 case 3:
49 if (*pb == uch)
50 return (unsigned char *)pb;
51 if (pb[1] == uch)
52 return (unsigned char *)pb + 1;
53 if (pb[2] == uch)
54 return (unsigned char *)pb + 2;
55 break;
56 case 4:
57 if (*pb == uch)
58 return (unsigned char *)pb;
59 if (pb[1] == uch)
60 return (unsigned char *)pb + 1;
61 if (pb[2] == uch)
62 return (unsigned char *)pb + 2;
63 if (pb[3] == uch)
64 return (unsigned char *)pb + 3;
65 break;
66 case 5:
67 if (*pb == uch)
68 return (unsigned char *)pb;
69 if (pb[1] == uch)
70 return (unsigned char *)pb + 1;
71 if (pb[2] == uch)
72 return (unsigned char *)pb + 2;
73 if (pb[3] == uch)
74 return (unsigned char *)pb + 3;
75 if (pb[4] == uch)
76 return (unsigned char *)pb + 4;
77 break;
78 case 6:
79 if (*pb == uch)
80 return (unsigned char *)pb;
81 if (pb[1] == uch)
82 return (unsigned char *)pb + 1;
83 if (pb[2] == uch)
84 return (unsigned char *)pb + 2;
85 if (pb[3] == uch)
86 return (unsigned char *)pb + 3;
87 if (pb[4] == uch)
88 return (unsigned char *)pb + 4;
89 if (pb[5] == uch)
90 return (unsigned char *)pb + 5;
91 break;
92 case 7:
93 if (*pb == uch)
94 return (unsigned char *)pb;
95 if (pb[1] == uch)
96 return (unsigned char *)pb + 1;
97 if (pb[2] == uch)
98 return (unsigned char *)pb + 2;
99 if (pb[3] == uch)
100 return (unsigned char *)pb + 3;
101 if (pb[4] == uch)
102 return (unsigned char *)pb + 4;
103 if (pb[5] == uch)
104 return (unsigned char *)pb + 5;
105 if (pb[6] == uch)
106 return (unsigned char *)pb + 6;
107 break;
108 }
109
110#elif 1 /* 4 byte loop unroll */
111 while (cb >= 4)
112 {
113 if (*pb == uch)
114 return (unsigned char *)pb;
115 if (pb[1] == uch)
116 return (unsigned char *)pb + 1;
117 if (pb[2] == uch)
118 return (unsigned char *)pb + 2;
119 if (pb[3] == uch)
120 return (unsigned char *)pb + 3;
121 cb -= 4;
122 pb += 4;
123 }
124 switch (cb & 3)
125 {
126 case 0:
127 break;
128 case 1:
129 if (*pb == uch)
130 return (unsigned char *)pb;
131 break;
132 case 2:
133 if (*pb == uch)
134 return (unsigned char *)pb;
135 if (pb[1] == uch)
136 return (unsigned char *)pb + 1;
137 break;
138 case 3:
139 if (*pb == uch)
140 return (unsigned char *)pb;
141 if (pb[1] == uch)
142 return (unsigned char *)pb + 1;
143 if (pb[2] == uch)
144 return (unsigned char *)pb + 2;
145 break;
146 }
147
148#else /* the basic loop */
149 while (cb > 0)
150 {
151 if (*pb == uch)
152 return (void *)pb;
153 cb--;
154 pb++;
155 }
156#endif
157 return 0;
158}
159
160#define memchr my_inline_memchr
161
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