| author | sl@SLION-WIN7.fritz.box |
| Fri, 15 Jun 2012 03:10:57 +0200 | |
| changeset 0 | bde4ae8d615e |
| permissions | -rw-r--r-- |
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/* |
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* strstr.c -- |
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* |
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* Source code for the "strstr" library routine. |
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* |
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* Copyright (c) 1988-1993 The Regents of the University of California. |
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* Copyright (c) 1994 Sun Microsystems, Inc. |
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* |
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* See the file "license.terms" for information on usage and redistribution |
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* of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
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* |
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* RCS: @(#) $Id: strstr.c,v 1.3.2.1 2005/04/12 18:28:56 kennykb Exp $ |
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*/ |
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|
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#include "tcl.h" |
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#ifndef NULL |
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#define NULL 0 |
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#endif |
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|
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/* |
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*---------------------------------------------------------------------- |
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* |
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* strstr -- |
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* |
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* Locate the first instance of a substring in a string. |
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* |
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* Results: |
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* If string contains substring, the return value is the |
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* location of the first matching instance of substring |
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* in string. If string doesn't contain substring, the |
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* return value is 0. Matching is done on an exact |
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* character-for-character basis with no wildcards or special |
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* characters. |
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* |
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* Side effects: |
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* None. |
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* |
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*---------------------------------------------------------------------- |
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*/ |
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|
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char * |
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strstr(string, substring) |
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register char *string; /* String to search. */ |
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char *substring; /* Substring to try to find in string. */ |
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{
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register char *a, *b; |
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|
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/* First scan quickly through the two strings looking for a |
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* single-character match. When it's found, then compare the |
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* rest of the substring. |
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*/ |
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|
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b = substring; |
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if (*b == 0) {
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return string; |
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} |
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for ( ; *string != 0; string += 1) {
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if (*string != *b) {
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continue; |
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} |
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a = string; |
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while (1) {
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if (*b == 0) {
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return string; |
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} |
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if (*a++ != *b++) {
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break; |
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} |
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} |
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b = substring; |
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} |
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return NULL; |
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} |