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[/] [openrisc/] [tags/] [gnu-src/] [newlib-1.18.0/] [newlib-1.18.0-or32-1.0rc1/] [newlib/] [libc/] [string/] [stpncpy.c] - Rev 345
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/* FUNCTION <<stpncpy>>---counted copy string returning a pointer to its end INDEX stpncpy ANSI_SYNOPSIS #include <string.h> char *stpncpy(char *<[dst]>, const char *<[src]>, size_t <[length]>); TRAD_SYNOPSIS #include <string.h> char *stpncpy(<[dst]>, <[src]>, <[length]>) char *<[dst]>; char *<[src]>; size_t <[length]>; DESCRIPTION <<stpncpy>> copies not more than <[length]> characters from the the string pointed to by <[src]> (including the terminating null character) to the array pointed to by <[dst]>. If the string pointed to by <[src]> is shorter than <[length]> characters, null characters are appended to the destination array until a total of <[length]> characters have been written. RETURNS This function returns a pointer to the end of the destination string, thus pointing to the trailing '\0', or, if the destination string is not null-terminated, pointing to dst + n. PORTABILITY <<stpncpy>> is a GNU extension, candidate for inclusion into POSIX/SUSv4. <<stpncpy>> requires no supporting OS subroutines. QUICKREF stpncpy gnu */ #include <string.h> #include <limits.h> /*SUPPRESS 560*/ /*SUPPRESS 530*/ /* Nonzero if either X or Y is not aligned on a "long" boundary. */ #define UNALIGNED(X, Y) \ (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1))) #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 #define TOO_SMALL(LEN) ((LEN) < sizeof (long)) char * _DEFUN (stpncpy, (dst, src), char *dst _AND _CONST char *src _AND size_t count) { char *ret = NULL; #if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__) long *aligned_dst; _CONST long *aligned_src; /* If SRC and DEST is aligned and count large enough, then copy words. */ if (!UNALIGNED (src, dst) && !TOO_SMALL (count)) { aligned_dst = (long*)dst; aligned_src = (long*)src; /* SRC and DEST are both "long int" aligned, try to do "long int" sized copies. */ while (count >= sizeof (long int) && !DETECTNULL(*aligned_src)) { count -= sizeof (long int); *aligned_dst++ = *aligned_src++; } dst = (char*)aligned_dst; src = (char*)aligned_src; } #endif /* not PREFER_SIZE_OVER_SPEED */ while (count > 0) { --count; if ((*dst++ = *src++) == '\0') { ret = dst - 1; break; } } while (count-- > 0) *dst++ = '\0'; return ret ? ret : dst; }