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[/] [openrisc/] [tags/] [gnu-src/] [newlib-1.18.0/] [newlib-1.18.0-or32-1.0rc1/] [newlib/] [libc/] [string/] [strncpy.c] - Rev 345
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/* FUNCTION <<strncpy>>---counted copy string INDEX strncpy ANSI_SYNOPSIS #include <string.h> char *strncpy(char *<[dst]>, const char *<[src]>, size_t <[length]>); TRAD_SYNOPSIS #include <string.h> char *strncpy(<[dst]>, <[src]>, <[length]>) char *<[dst]>; char *<[src]>; size_t <[length]>; DESCRIPTION <<strncpy>> 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 the initial value of <[dst]>. PORTABILITY <<strncpy>> is ANSI C. <<strncpy>> requires no supporting OS subroutines. QUICKREF strncpy ansi pure */ #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 (strncpy, (dst0, src0), char *dst0 _AND _CONST char *src0 _AND size_t count) { #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) char *dscan; _CONST char *sscan; dscan = dst0; sscan = src0; while (count > 0) { --count; if ((*dscan++ = *sscan++) == '\0') break; } while (count-- > 0) *dscan++ = '\0'; return dst0; #else char *dst = dst0; _CONST char *src = src0; 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; } while (count > 0) { --count; if ((*dst++ = *src++) == '\0') break; } while (count-- > 0) *dst++ = '\0'; return dst0; #endif /* not PREFER_SIZE_OVER_SPEED */ }