| /* |
| FUNCTION |
| <<strcat>>---concatenate strings |
| |
| INDEX |
| strcat |
| |
| ANSI_SYNOPSIS |
| #include <string.h> |
| char *strcat(char *<[dst]>, const char *<[src]>); |
| |
| TRAD_SYNOPSIS |
| #include <string.h> |
| char *strcat(<[dst]>, <[src]>) |
| char *<[dst]>; |
| char *<[src]>; |
| |
| DESCRIPTION |
| <<strcat>> appends a copy of 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]>. |
| |
| RETURNS |
| This function returns the initial value of <[dst]> |
| |
| PORTABILITY |
| <<strcat>> is ANSI C. |
| |
| <<strcat>> requires no supporting OS subroutines. |
| |
| QUICKREF |
| strcat 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 |
| |
| |
| /*SUPPRESS 560*/ |
| /*SUPPRESS 530*/ |
| |
| char * |
| _DEFUN (strcat, (s1, s2), |
| char *s1 _AND |
| _CONST char *s2) |
| { |
| #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) |
| char *s = s1; |
| |
| while (*s1) |
| s1++; |
| |
| while (*s1++ = *s2++) |
| ; |
| 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, we can |
| just use strcpy to do the work for us now. |
| |
| ?!? We might want to just include strcpy here. |
| Also, this will cause many more unaligned string copies because |
| s1 is much less likely to be aligned. I don't know if its worth |
| tweaking strcpy to handle this better. */ |
| strcpy (s1, s2); |
| |
| return s; |
| #endif /* not PREFER_SIZE_OVER_SPEED */ |
| } |