1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
|
/*
* strncpy.S -- strncmp function. On at least some MIPS chips, you get better
* code by hand unrolling the loops, and by using store words to zero the
* remainder of the buffer than the default newlib C version.
*
* Copyright (c) 2001 Red Hat, Inc.
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice is included verbatim in any distributions. No written agreement,
* license, or royalty fee is required for any of the authorized uses.
* Modifications to this software may be copyrighted by their authors
* and need not follow the licensing terms described here, provided that
* the new terms are clearly indicated on the first page of each file where
* they apply. */
#include <string.h>
#include <stddef.h>
#include <stdlib.h>
#if !defined(__GNUC__) || (__GNUC__ < 3)
#define __builtin_expect(a,b) a
#else
#ifdef __mips64
/* Don't use limits test for the size of long, in order to allow the use of
64-bit stores on MIPS3 machines, even if -mlong32 was used. */
typedef unsigned word_type __attribute__ ((mode (DI)));
#else
typedef unsigned word_type __attribute__ ((mode (SI)));
#endif
typedef unsigned si_type __attribute__ ((mode (SI)));
typedef unsigned hi_type __attribute__ ((mode (HI)));
#ifndef UNROLL_FACTOR
#define UNROLL_FACTOR 4
#elif (UNROLL_FACTOR != 2) && (UNROLL_FACTOR != 4)
#error "UNROLL_FACTOR must be 2 or 4"
#endif
#endif
char *
strncpy (char *dst0, const char *src0, size_t count)
{
#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) || defined(__mips16) || !defined(__GNUC__) || (__GNUC__ < 3)
char *dst, *end;
const char *src;
int ch;
dst = dst0;
src = src0;
end = dst + count;
while (dst != end)
{
*dst++ = ch = *src++;
if (__builtin_expect (ch == '\0', 0))
{
while (dst != end)
*dst++ = '\0';
break;
}
}
return dst0;
#else
unsigned char *dst;
unsigned char *dst_end;
unsigned char *end;
const unsigned char *src;
int ch0, ch1;
#if UNROLL_FACTOR > 2
int ch2, ch3;
#endif
int ch;
int odd_bytes;
size_t long_count;
dst = (unsigned char *)dst0;
src = (unsigned const char *)src0;
if (__builtin_expect (count >= 4, 1))
{
odd_bytes = (count & (UNROLL_FACTOR - 1));
count -= odd_bytes;
do
{
ch0 = src[0];
ch1 = src[1];
#if UNROLL_FACTOR > 2
ch2 = src[2];
ch3 = src[3];
#endif
src += UNROLL_FACTOR;
count -= UNROLL_FACTOR;
dst[0] = ch0;
if (ch0 == '\0')
goto found_null0;
dst[1] = ch1;
if (ch1 == '\0')
goto found_null1;
#if UNROLL_FACTOR > 2
dst[2] = ch2;
if (ch2 == '\0')
goto found_null2;
dst[3] = ch3;
if (ch3 == '\0')
goto found_null3;
#endif
dst += UNROLL_FACTOR;
}
while (count);
/* fall through, count == 0, no null found, deal with last bytes */
count = odd_bytes;
}
end = dst + count;
while (dst != end)
{
*dst++ = ch = *src++;
if (ch == '\0')
{
while (dst != end)
*dst++ = '\0';
break;
}
}
return dst0;
/* Found null byte in first byte, count has been decremented by 4, null has
been stored in dst[0]. */
found_null0:
count++; /* add 1 to cover remaining byte */
dst -= 1; /* adjust dst += 4 gets correct ptr */
/* fall through */
/* Found null byte in second byte, count has been decremented by 4, null has
been stored in dst[1]. */
found_null1:
#if UNROLL_FACTOR > 2
count++; /* add 1 to cover remaining byte */
dst -= 1; /* adjust dst += 4 gets correct ptr */
/* fall through */
/* Found null byte in third byte, count has been decremented by 4, null has
been stored in dst[2]. */
found_null2:
count++; /* add 1 to cover remaining byte */
dst -= 1; /* adjust dst += 4 gets correct ptr */
/* fall through */
/* Found null byte in fourth byte, count is accurate, dst has not been
updated yet. */
found_null3:
#endif
count += odd_bytes; /* restore odd byte count */
dst += UNROLL_FACTOR;
/* Zero fill remainder of the array. Unroll the loop, and use word/dword
stores where we can. */
while (count && (((long)dst) & (sizeof (word_type) - 1)) != 0)
{
count--;
*dst++ = 0;
}
while (count >= UNROLL_FACTOR*sizeof (word_type))
{
count -= UNROLL_FACTOR*sizeof (word_type);
dst += UNROLL_FACTOR*sizeof (word_type);
#if UNROLL_FACTOR > 2
((word_type *)(void *)dst)[-4] = 0;
((word_type *)(void *)dst)[-3] = 0;
#endif
((word_type *)(void *)dst)[-2] = 0;
((word_type *)(void *)dst)[-1] = 0;
}
#if UNROLL_FACTOR > 2
if (count >= 2*sizeof (word_type))
{
count -= 2*sizeof (word_type);
((word_type *)(void *)dst)[0] = 0;
((word_type *)(void *)dst)[1] = 0;
dst += 2*sizeof (word_type);
}
#endif
if (count >= sizeof (word_type))
{
count -= sizeof (word_type);
((word_type *)(void *)dst)[0] = 0;
dst += sizeof (word_type);
}
#ifdef __mips64
if (count >= sizeof (si_type))
{
count -= sizeof (si_type);
((si_type *)(void *)dst)[0] = 0;
dst += sizeof (si_type);
}
#endif
if (count >= sizeof (hi_type))
{
count -= sizeof (hi_type);
((hi_type *)(void *)dst)[0] = 0;
dst += sizeof (hi_type);
}
if (count)
*dst = '\0';
return dst0;
#endif
}
|
