| 1 | /* Simple implementation of strstr for systems without it. |
| 2 | This function is in the public domain. */ |
| 3 | |
| 4 | /* |
| 5 | |
| 6 | NAME |
| 7 | |
| 8 | strstr -- locate first occurance of a substring |
| 9 | |
| 10 | SYNOPSIS |
| 11 | |
| 12 | #include <string.h> |
| 13 | |
| 14 | char *strstr (char *s1, char *s2) |
| 15 | |
| 16 | DESCRIPTION |
| 17 | |
| 18 | Locates the first occurance in the string pointed to by S1 of |
| 19 | the string pointed to by S2. Returns a pointer to the substring |
| 20 | found, or a NULL pointer if not found. If S2 points to a string |
| 21 | with zero length, the function returns S1. |
| 22 | |
| 23 | BUGS |
| 24 | |
| 25 | */ |
| 26 | |
| 27 | |
| 28 | /* FIXME: The above description is ANSI compiliant. This routine has not |
| 29 | been validated to comply with it. -fnf */ |
| 30 | |
| 31 | char * |
| 32 | strstr (s1, s2) |
| 33 | char *s1, *s2; |
| 34 | { |
| 35 | register char *p = s1; |
| 36 | extern char *strchr (); |
| 37 | extern int strncmp (); |
| 38 | #if __GNUC__==2 |
| 39 | extern __SIZE_TYPE__ strlen (); |
| 40 | #endif |
| 41 | register int len = strlen (s2); |
| 42 | |
| 43 | for (; (p = strchr (p, *s2)) != 0; p++) |
| 44 | { |
| 45 | if (strncmp (p, s2, len) == 0) |
| 46 | { |
| 47 | return (p); |
| 48 | } |
| 49 | } |
| 50 | return (0); |
| 51 | } |