diff options
Diffstat (limited to 'newlib/libc/string/memmem.c')
-rw-r--r-- | newlib/libc/string/memmem.c | 102 |
1 files changed, 0 insertions, 102 deletions
diff --git a/newlib/libc/string/memmem.c b/newlib/libc/string/memmem.c deleted file mode 100644 index 25704e467..000000000 --- a/newlib/libc/string/memmem.c +++ /dev/null @@ -1,102 +0,0 @@ -/* Byte-wise substring search, using the Two-Way algorithm. - * Copyright (C) 2008 Eric Blake - * Permission to use, copy, modify, and distribute this software - * is freely granted, provided that this notice is preserved. - */ - -/* -FUNCTION - <<memmem>>---find memory segment - -INDEX - memmem - -ANSI_SYNOPSIS - #include <string.h> - char *memmem(const void *<[s1]>, size_t <[l1]>, const void *<[s2]>, - size_t <[l2]>); - -DESCRIPTION - - Locates the first occurrence in the memory region pointed to - by <[s1]> with length <[l1]> of the sequence of bytes pointed - to by <[s2]> of length <[l2]>. If you already know the - lengths of your haystack and needle, <<memmem>> can be much - faster than <<strstr>>. - -RETURNS - Returns a pointer to the located segment, or a null pointer if - <[s2]> is not found. If <[l2]> is 0, <[s1]> is returned. - -PORTABILITY -<<memmem>> is a newlib extension. - -<<memmem>> requires no supporting OS subroutines. - -QUICKREF - memmem pure -*/ - -#include <string.h> - -#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__) -# define RETURN_TYPE void * -# define AVAILABLE(h, h_l, j, n_l) ((j) <= (h_l) - (n_l)) -# include "str-two-way.h" -#endif - -void * -_DEFUN (memmem, (haystack_start, haystack_len, needle_start, needle_len), - const void *haystack_start _AND - size_t haystack_len _AND - const void *needle_start _AND - size_t needle_len) -{ - /* Abstract memory is considered to be an array of 'unsigned char' values, - not an array of 'char' values. See ISO C 99 section 6.2.6.1. */ - const unsigned char *haystack = (const unsigned char *) haystack_start; - const unsigned char *needle = (const unsigned char *) needle_start; - - if (needle_len == 0) - /* The first occurrence of the empty string is deemed to occur at - the beginning of the string. */ - return (void *) haystack; - -#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) - - /* Less code size, but quadratic performance in the worst case. */ - while (needle_len <= haystack_len) - { - if (!memcmp (haystack, needle, needle_len)) - return (void *) haystack; - haystack++; - haystack_len--; - } - return NULL; - -#else /* compilation for speed */ - - /* Larger code size, but guaranteed linear performance. */ - - /* Sanity check, otherwise the loop might search through the whole - memory. */ - if (haystack_len < needle_len) - return NULL; - - /* Use optimizations in memchr when possible, to reduce the search - size of haystack using a linear algorithm with a smaller - coefficient. However, avoid memchr for long needles, since we - can often achieve sublinear performance. */ - if (needle_len < LONG_NEEDLE_THRESHOLD) - { - haystack = memchr (haystack, *needle, haystack_len); - if (!haystack || needle_len == 1) - return (void *) haystack; - haystack_len -= haystack - (const unsigned char *) haystack_start; - if (haystack_len < needle_len) - return NULL; - return two_way_short_needle (haystack, haystack_len, needle, needle_len); - } - return two_way_long_needle (haystack, haystack_len, needle, needle_len); -#endif /* compilation for speed */ -} |