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https://opencores.org/ocsvn/openrisc_2011-10-31/openrisc_2011-10-31/trunk
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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.17.0/] [newlib/] [libc/] [string/] [strchr.c] - Rev 194
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/* FUNCTION <<strchr>>---search for character in string INDEX strchr ANSI_SYNOPSIS #include <string.h> char * strchr(const char *<[string]>, int <[c]>); TRAD_SYNOPSIS #include <string.h> char * strchr(<[string]>, <[c]>); const char *<[string]>; int <[c]>; DESCRIPTION This function finds the first occurence of <[c]> (converted to a char) in the string pointed to by <[string]> (including the terminating null character). RETURNS Returns a pointer to the located character, or a null pointer if <[c]> does not occur in <[string]>. PORTABILITY <<strchr>> is ANSI C. <<strchr>> requires no supporting OS subroutines. QUICKREF strchr ansi pure */ #include <string.h> #include <limits.h> /* Nonzero if X is not aligned on a "long" boundary. */ #define UNALIGNED(X) ((long)X & (sizeof (long) - 1)) /* How many bytes are loaded each iteration of the word copy loop. */ #define LBLOCKSIZE (sizeof (long)) #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 /* DETECTCHAR returns nonzero if (long)X contains the byte used to fill (long)MASK. */ #define DETECTCHAR(X,MASK) (DETECTNULL(X ^ MASK)) char * _DEFUN (strchr, (s1, i), _CONST char *s1 _AND int i) { _CONST unsigned char *s = (_CONST unsigned char *)s1; unsigned char c = i; #if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__) unsigned long mask,j; unsigned long *aligned_addr; /* Special case for finding 0. */ if (!c) { while (UNALIGNED (s)) { if (!*s) return (char *) s; s++; } /* Operate a word at a time. */ aligned_addr = (unsigned long *) s; while (!DETECTNULL (*aligned_addr)) aligned_addr++; /* Found the end of string. */ s = (const unsigned char *) aligned_addr; while (*s) s++; return (char *) s; } /* All other bytes. Align the pointer, then search a long at a time. */ while (UNALIGNED (s)) { if (!*s) return NULL; if (*s == c) return (char *) s; s++; } mask = c; for (j = 8; j < LBLOCKSIZE * 8; j <<= 1) mask = (mask << j) | mask; aligned_addr = (unsigned long *) s; while (!DETECTNULL (*aligned_addr) && !DETECTCHAR (*aligned_addr, mask)) aligned_addr++; /* The block of bytes currently pointed to by aligned_addr contains either a null or the target char, or both. We catch it using the bytewise search. */ s = (unsigned char *) aligned_addr; #endif /* not PREFER_SIZE_OVER_SPEED */ while (*s && *s != c) s++; if (*s == c) return (char *)s; return NULL; }
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