74 lines
1.4 KiB
C
74 lines
1.4 KiB
C
/* strstr.c - file for string */
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/* Copyright 1992-1993 Wind River Systems, Inc. */
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/*
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modification history
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--------------------
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01c,25feb93,jdi documentation cleanup for 5.1.
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01b,20sep92,smb documentation additions
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01a,08jul92,smb written and documented.
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*/
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/*
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DESCRIPTION
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INCLUDE FILES: string.h
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SEE ALSO: American National Standard X3.159-1989
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NOMANUAL
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*/
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#include "vxWorks.h"
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#include "string.h"
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/******************************************************************************
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*
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* strstr - find the first occurrence of a substring in a string (ANSI)
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*
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* This routine locates the first occurrence in string <s>
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* of the sequence of characters (excluding the terminating null character)
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* in the string <find>.
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*
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* INCLUDE FILES: string.h
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*
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* RETURNS:
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* A pointer to the located substring, or <s> if <find> points to a
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* zero-length string, or NULL if the string is not found.
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*/
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char * strstr
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(
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const char * s, /* string to search */
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const char * find /* substring to look for */
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)
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{
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char *t1;
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char *t2;
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char c;
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char c2;
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if ((c = *find++) == EOS) /* <find> an empty string */
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return (CHAR_FROM_CONST(s));
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FOREVER
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{
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while (((c2 = *s++) != EOS) && (c2 != c))
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;
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if (c2 == EOS)
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return (NULL);
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t1 = CHAR_FROM_CONST(s);
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t2 = CHAR_FROM_CONST(find);
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while (((c2 = *t2++) != 0) && (*t1++ == c2))
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;
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if (c2 == EOS)
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return (CHAR_FROM_CONST(s - 1));
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}
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}
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