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Diffstat (limited to 'newlib/libc/string/memrchr.c')
-rw-r--r-- | newlib/libc/string/memrchr.c | 134 |
1 files changed, 0 insertions, 134 deletions
diff --git a/newlib/libc/string/memrchr.c b/newlib/libc/string/memrchr.c deleted file mode 100644 index 42d9d147b..000000000 --- a/newlib/libc/string/memrchr.c +++ /dev/null @@ -1,134 +0,0 @@ -/* -FUNCTION - <<memrchr>>---reverse search for character in memory - -INDEX - memrchr - -ANSI_SYNOPSIS - #include <string.h> - void *memrchr(const void *<[src]>, int <[c]>, size_t <[length]>); - -TRAD_SYNOPSIS - #include <string.h> - void *memrchr(<[src]>, <[c]>, <[length]>) - void *<[src]>; - void *<[c]>; - size_t <[length]>; - -DESCRIPTION - This function searches memory starting at <[length]> bytes - beyond <<*<[src]>>> backwards for the character <[c]>. - The search only ends with the first occurrence of <[c]>; in - particular, <<NUL>> does not terminate the search. - -RETURNS - If the character <[c]> is found within <[length]> characters - of <<*<[src]>>>, a pointer to the character is returned. If - <[c]> is not found, then <<NULL>> is returned. - -PORTABILITY -<<memrchr>> is a GNU extension. - -<<memrchr>> requires no supporting OS subroutines. - -QUICKREF - memrchr -*/ - -#include <_ansi.h> -#include <string.h> -#include <limits.h> - -/* Nonzero if X is not aligned on a "long" boundary. */ -#define UNALIGNED(X) ((long)(X + 1) & (sizeof (long) - 1)) - -/* How many bytes are loaded each iteration of the word copy loop. */ -#define LBLOCKSIZE (sizeof (long)) - -/* Threshhold for punting to the bytewise iterator. */ -#define TOO_SMALL(LEN) ((LEN) < LBLOCKSIZE) - -#if LONG_MAX == 2147483647L -#define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080) -#else -#if LONG_MAX == 9223372036854775807L -/* Nonzero if X (a long int) contains a NULL byte. */ -#define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080) -#else -#error long int is not a 32bit or 64bit type. -#endif -#endif - -#ifndef DETECTNULL -#error long int is not a 32bit or 64bit byte -#endif - -/* DETECTCHAR returns nonzero if (long)X contains the byte used - to fill (long)MASK. */ -#define DETECTCHAR(X,MASK) (DETECTNULL(X ^ MASK)) - -_PTR -_DEFUN (memrchr, (src_void, c, length), - _CONST _PTR src_void _AND - int c _AND - size_t length) -{ - _CONST unsigned char *src = (_CONST unsigned char *) src_void + length - 1; - unsigned char d = c; - -#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__) - unsigned long *asrc; - unsigned long mask; - int i; - - while (UNALIGNED (src)) - { - if (!length--) - return NULL; - if (*src == d) - return (void *) src; - src--; - } - - if (!TOO_SMALL (length)) - { - /* If we get this far, we know that length is large and src is - word-aligned. */ - /* The fast code reads the source one word at a time and only - performs the bytewise search on word-sized segments if they - contain the search character, which is detected by XORing - the word-sized segment with a word-sized block of the search - character and then detecting for the presence of NUL in the - result. */ - asrc = (unsigned long *) (src - LBLOCKSIZE + 1); - mask = d << 8 | d; - mask = mask << 16 | mask; - for (i = 32; i < LBLOCKSIZE * 8; i <<= 1) - mask = (mask << i) | mask; - - while (length >= LBLOCKSIZE) - { - if (DETECTCHAR (*asrc, mask)) - break; - length -= LBLOCKSIZE; - asrc--; - } - - /* If there are fewer than LBLOCKSIZE characters left, - then we resort to the bytewise loop. */ - - src = (unsigned char *) asrc + LBLOCKSIZE - 1; - } - -#endif /* not PREFER_SIZE_OVER_SPEED */ - - while (length--) - { - if (*src == d) - return (void *) src; - src--; - } - - return NULL; -} |