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authorThomas Martitz <kugel@rockbox.org>2010-05-06 21:04:40 +0000
committerThomas Martitz <kugel@rockbox.org>2010-05-06 21:04:40 +0000
commit50a6ca39ad4ed01922aa4f755f0ca579788226cf (patch)
treec7881b015b220558167310345b162324c96be15a /firmware/libc/strchr.c
parentadb506df14aded06ed6e9ebf8540e6fd383ffd6a (diff)
downloadrockbox-50a6ca39ad4ed01922aa4f755f0ca579788226cf.tar.gz
rockbox-50a6ca39ad4ed01922aa4f755f0ca579788226cf.zip
Move c/h files implementing/defining standard library stuff into a new libc directory, also standard'ify some parts of the code base (almost entirely #include fixes).
This is to a) to cleanup firmware/common and firmware/include a bit, but also b) for Rockbox as an application which should use the host system's c library and headers, separating makes it easy to exclude our files from the build. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@25850 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'firmware/libc/strchr.c')
-rw-r--r--firmware/libc/strchr.c108
1 files changed, 108 insertions, 0 deletions
diff --git a/firmware/libc/strchr.c b/firmware/libc/strchr.c
new file mode 100644
index 0000000000..96acf5edf6
--- /dev/null
+++ b/firmware/libc/strchr.c
@@ -0,0 +1,108 @@
1/*
2FUNCTION
3 <<strchr>>---search for character in string
4
5INDEX
6 strchr
7
8ANSI_SYNOPSIS
9 #include <string.h>
10 char * strchr(const char *<[string]>, int <[c]>);
11
12TRAD_SYNOPSIS
13 #include <string.h>
14 char * strchr(<[string]>, <[c]>);
15 char *<[string]>;
16 int *<[c]>;
17
18DESCRIPTION
19 This function finds the first occurence of <[c]> (converted to
20 a char) in the string pointed to by <[string]> (including the
21 terminating null character).
22
23RETURNS
24 Returns a pointer to the located character, or a null pointer
25 if <[c]> does not occur in <[string]>.
26
27PORTABILITY
28<<strchr>> is ANSI C.
29
30<<strchr>> requires no supporting OS subroutines.
31
32QUICKREF
33 strchr ansi pure
34*/
35
36#include <string.h>
37#include <limits.h>
38
39/* Nonzero if X is not aligned on a "long" boundary. */
40#define UNALIGNED(X) ((long)X & (sizeof (long) - 1))
41
42/* How many bytes are loaded each iteration of the word copy loop. */
43#define LBLOCKSIZE (sizeof (long))
44
45#if LONG_MAX == 2147483647L
46#define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
47#else
48#if LONG_MAX == 9223372036854775807L
49/* Nonzero if X (a long int) contains a NULL byte. */
50#define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
51#else
52#error long int is not a 32bit or 64bit type.
53#endif
54#endif
55
56/* DETECTCHAR returns nonzero if (long)X contains the byte used
57 to fill (long)MASK. */
58#define DETECTCHAR(X,MASK) (DETECTNULL(X ^ MASK))
59
60char *
61_DEFUN (strchr, (s1, i),
62 _CONST char *s1 _AND
63 int i)
64{
65 _CONST unsigned char *s = (_CONST unsigned char *)s1;
66#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
67 unsigned char c = (unsigned int)i;
68
69 while (*s && *s != c)
70 {
71 s++;
72 }
73
74 if (*s != c)
75 {
76 s = NULL;
77 }
78
79 return (char *) s;
80#else
81 unsigned char c = (unsigned char)i;
82 unsigned long mask,j;
83 unsigned long *aligned_addr;
84
85 if (!UNALIGNED (s))
86 {
87 mask = 0;
88 for (j = 0; j < LBLOCKSIZE; j++)
89 mask = (mask << 8) | c;
90
91 aligned_addr = (unsigned long*)s;
92 while (!DETECTNULL (*aligned_addr) && !DETECTCHAR (*aligned_addr, mask))
93 aligned_addr++;
94
95 /* The block of bytes currently pointed to by aligned_addr
96 contains either a null or the target char, or both. We
97 catch it using the bytewise search. */
98
99 s = (unsigned char*)aligned_addr;
100 }
101
102 while (*s && *s != c)
103 s++;
104 if (*s == c)
105 return (char *)s;
106 return NULL;
107#endif /* not PREFER_SIZE_OVER_SPEED */
108}