URL
https://opencores.org/ocsvn/openrisc_me/openrisc_me/trunk
Subversion Repositories openrisc_me
[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libc/] [string/] [strstr.c] - Rev 273
Go to most recent revision | Compare with Previous | Blame | View Log
/* FUNCTION <<strstr>>---find string segment INDEX strstr ANSI_SYNOPSIS #include <string.h> char *strstr(const char *<[s1]>, const char *<[s2]>); TRAD_SYNOPSIS #include <string.h> char *strstr(<[s1]>, <[s2]>) char *<[s1]>; char *<[s2]>; DESCRIPTION Locates the first occurrence in the string pointed to by <[s1]> of the sequence of characters in the string pointed to by <[s2]> (excluding the terminating null character). RETURNS Returns a pointer to the located string segment, or a null pointer if the string <[s2]> is not found. If <[s2]> points to a string with zero length, <[s1]> is returned. PORTABILITY <<strstr>> is ANSI C. <<strstr>> requires no supporting OS subroutines. QUICKREF strstr ansi pure */ #include <string.h> #if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__) # define RETURN_TYPE char * # define AVAILABLE(h, h_l, j, n_l) \ (!memchr ((h) + (h_l), '\0', (j) + (n_l) - (h_l)) \ && ((h_l) = (j) + (n_l))) # include "str-two-way.h" #endif char * _DEFUN (strstr, (searchee, lookfor), _CONST char *searchee _AND _CONST char *lookfor) { #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) /* Less code size, but quadratic performance in the worst case. */ if (*searchee == 0) { if (*lookfor) return (char *) NULL; return (char *) searchee; } while (*searchee) { size_t i; i = 0; while (1) { if (lookfor[i] == 0) { return (char *) searchee; } if (lookfor[i] != searchee[i]) { break; } i++; } searchee++; } return (char *) NULL; #else /* compilation for speed */ /* Larger code size, but guaranteed linear performance. */ const char *haystack = searchee; const char *needle = lookfor; size_t needle_len; /* Length of NEEDLE. */ size_t haystack_len; /* Known minimum length of HAYSTACK. */ int ok = 1; /* True if NEEDLE is prefix of HAYSTACK. */ /* Determine length of NEEDLE, and in the process, make sure HAYSTACK is at least as long (no point processing all of a long NEEDLE if HAYSTACK is too short). */ while (*haystack && *needle) ok &= *haystack++ == *needle++; if (*needle) return NULL; if (ok) return (char *) searchee; /* Reduce the size of haystack using strchr, since it has a smaller linear coefficient than the Two-Way algorithm. */ needle_len = needle - lookfor; haystack = strchr (searchee + 1, *lookfor); if (!haystack || needle_len == 1) return (char *) haystack; haystack_len = (haystack > searchee + needle_len ? 1 : needle_len + searchee - haystack); /* Perform the search. */ if (needle_len < LONG_NEEDLE_THRESHOLD) return two_way_short_needle ((const unsigned char *) haystack, haystack_len, (const unsigned char *) lookfor, needle_len); return two_way_long_needle ((const unsigned char *) haystack, haystack_len, (const unsigned char *) lookfor, needle_len); #endif /* compilation for speed */ }
Go to most recent revision | Compare with Previous | Blame | View Log