URL
https://opencores.org/ocsvn/openrisc_2011-10-31/openrisc_2011-10-31/trunk
Subversion Repositories openrisc_2011-10-31
[/] [openrisc/] [tags/] [gnu-src/] [newlib-1.18.0/] [newlib-1.18.0-or32-1.0rc2/] [newlib/] [libc/] [string/] [strncat.c] - Rev 520
Compare with Previous | Blame | View Log
/* FUNCTION <<strncat>>---concatenate strings INDEX strncat ANSI_SYNOPSIS #include <string.h> char *strncat(char *<[dst]>, const char *<[src]>, size_t <[length]>); TRAD_SYNOPSIS #include <string.h> char *strncat(<[dst]>, <[src]>, <[length]>) char *<[dst]>; char *<[src]>; size_t <[length]>; DESCRIPTION <<strncat>> appends not more than <[length]> characters from the string pointed to by <[src]> (including the terminating null character) to the end of the string pointed to by <[dst]>. The initial character of <[src]> overwrites the null character at the end of <[dst]>. A terminating null character is always appended to the result WARNINGS Note that a null is always appended, so that if the copy is limited by the <[length]> argument, the number of characters appended to <[dst]> is <<n + 1>>. RETURNS This function returns the initial value of <[dst]> PORTABILITY <<strncat>> is ANSI C. <<strncat>> requires no supporting OS subroutines. QUICKREF strncat ansi pure */ #include <string.h> #include <limits.h> /* Nonzero if X is aligned on a "long" boundary. */ #define ALIGNED(X) \ (((long)X & (sizeof (long) - 1)) == 0) #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 char * _DEFUN (strncat, (s1, s2, n), char *s1 _AND _CONST char *s2 _AND size_t n) { #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) char *s = s1; while (*s1) s1++; while (n-- != 0 && (*s1++ = *s2++)) { if (n == 0) *s1 = '\0'; } return s; #else char *s = s1; /* Skip over the data in s1 as quickly as possible. */ if (ALIGNED (s1)) { unsigned long *aligned_s1 = (unsigned long *)s1; while (!DETECTNULL (*aligned_s1)) aligned_s1++; s1 = (char *)aligned_s1; } while (*s1) s1++; /* s1 now points to the its trailing null character, now copy up to N bytes from S2 into S1 stopping if a NULL is encountered in S2. It is not safe to use strncpy here since it copies EXACTLY N characters, NULL padding if necessary. */ while (n-- != 0 && (*s1++ = *s2++)) { if (n == 0) *s1 = '\0'; } return s; #endif /* not PREFER_SIZE_OVER_SPEED */ }