| 0,0 → 1,114 |
|---|
| /* |
| 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 */ |
| } |