···1+/*
2+FUNCTION
3+ <<memccpy>>---copy memory regions with end-token check
4+ANSI_SYNOPSIS
5+ #include <string.h>
6+ void* memccpy(void *restrict <[out]>, const void *restrict <[in]>,
7+ int <[endchar]>, size_t <[n]>);
8+TRAD_SYNOPSIS
9+ void *memccpy(<[out]>, <[in]>, <[endchar]>, <[n]>
10+ void *<[out]>;
11+ void *<[in]>;
12+ int <[endchar]>;
13+ size_t <[n]>;
14+DESCRIPTION
15+ This function copies up to <[n]> bytes from the memory region
16+ pointed to by <[in]> to the memory region pointed to by
17+ <[out]>. If a byte matching the <[endchar]> is encountered,
18+ the byte is copied and copying stops.
19+ If the regions overlap, the behavior is undefined.
20+RETURNS
21+ <<memccpy>> returns a pointer to the first byte following the
22+ <[endchar]> in the <[out]> region. If no byte matching
23+ <[endchar]> was copied, then <<NULL>> is returned.
24+PORTABILITY
25+<<memccpy>> is a GNU extension.
26+<<memccpy>> requires no supporting OS subroutines.
27+ */
28+#include <stddef.h>
29+#include <string.h>
30+#include <limits.h>
31+#include "_ansi.h" /* for _DEFUN */
32+33+/* Nonzero if either X or Y is not aligned on a "long" boundary. */
34+#define ROCKBOX_UNALIGNED(X, Y) \
35+ (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1)))
36+/* How many bytes are copied each iteration of the word copy loop. */
37+#define LITTLEBLOCKSIZE (sizeof (long))
38+/* Threshhold for punting to the byte copier. */
39+#define TOO_SMALL(LEN) ((LEN) < LITTLEBLOCKSIZE)
40+/* Macros for detecting endchar */
41+#if LONG_MAX == 2147483647L
42+#define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
43+#else
44+#if LONG_MAX == 9223372036854775807L
45+/* Nonzero if X (a long int) contains a NULL byte. */
46+#define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
47+#else
48+#error long int is not a 32bit or 64bit type.
49+#endif
50+#endif
51+_PTR
52+_DEFUN (memccpy, (dst0, src0, endchar, len0),
53+ _PTR __restrict dst0 _AND
54+ _CONST _PTR __restrict src0 _AND
55+ int endchar0 _AND
56+ size_t len0)
57+{
58+#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
59+ _PTR ptr = NULL;
60+ char *dst = (char *) dst0;
61+ char *src = (char *) src0;
62+ char endchar = endchar0 & 0xff;
63+ while (len0--)
64+ {
65+ if ((*dst++ = *src++) == endchar)
66+ {
67+ ptr = dst;
68+ break;
69+ }
70+ }
71+ return ptr;
72+#else
73+ _PTR ptr = NULL;
74+ char *dst = dst0;
75+ _CONST char *src = src0;
76+ long *aligned_dst;
77+ _CONST long *aligned_src;
78+ char endchar = endchar0 & 0xff;
79+ /* If the size is small, or either SRC or DST is unaligned,
80+ then punt into the byte copy loop. This should be rare. */
81+ if (!TOO_SMALL(len0) && !ROCKBOX_UNALIGNED (src, dst))
82+ {
83+ unsigned int i;
84+ unsigned long mask = 0;
85+ aligned_dst = (long*)dst;
86+ aligned_src = (long*)src;
87+ /* The fast code reads the ASCII one word at a time and only
88+ performs the bytewise search on word-sized segments if they
89+ contain the search character, which is detected by XORing
90+ the word-sized segment with a word-sized block of the search
91+ character and then detecting for the presence of NULL in the
92+ result. */
93+ for (i = 0; i < LITTLEBLOCKSIZE; i++)
94+ mask = (mask << 8) + endchar;
95+ /* Copy one long word at a time if possible. */
96+ while (len0 >= LITTLEBLOCKSIZE)
97+ {
98+ unsigned long buffer = (unsigned long)(*aligned_src);
99+ buffer ^= mask;
100+ if (DETECTNULL (buffer))
101+ break; /* endchar is found, go byte by byte from here */
102+ *aligned_dst++ = *aligned_src++;
103+ len0 -= LITTLEBLOCKSIZE;
104+ }
105+ /* Pick up any residual with a byte copier. */
106+ dst = (char*)aligned_dst;
107+ src = (char*)aligned_src;
108+ }
109+ while (len0--)
110+ {
111+ if ((*dst++ = *src++) == endchar)
112+ {
113+ ptr = dst;
114+ break;
115+ }
116+ }
117+ return ptr;
118+#endif /* not PREFER_SIZE_OVER_SPEED */
119+}