597 lines
14 KiB
C
597 lines
14 KiB
C
/*
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* Copyright (c) 1980, 1993
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* The Regents of the University of California. All rights reserved.
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*
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#ifndef lint
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static const char copyright[] =
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"@(#) Copyright (c) 1980, 1993\n\
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The Regents of the University of California. All rights reserved.\n";
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#endif
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#ifndef lint
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static const char sccsid[] = "@(#)regexp.c 8.1 (Berkeley) 6/6/93";
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#endif
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#include <ctype.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <string.h>
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#include "extern.h"
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static void expconv(void);
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bool _escaped; /* true if we are currently x_escaped */
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char *s_start; /* start of string */
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bool l_onecase; /* true if upper and lower equivalent */
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#define makelower(c) (isupper((c)) ? tolower((c)) : (c))
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/* STRNCMP - like strncmp except that we convert the
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* first string to lower case before comparing
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* if l_onecase is set.
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*/
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int
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STRNCMP(register char *s1, register char *s2, register int len)
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{
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if (l_onecase) {
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do
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if (*s2 - makelower(*s1))
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return (*s2 - makelower(*s1));
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else {
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s2++;
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s1++;
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}
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while (--len);
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} else {
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do
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if (*s2 - *s1)
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return (*s2 - *s1);
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else {
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s2++;
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s1++;
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}
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while (--len);
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}
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return(0);
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}
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/* The following routine converts an irregular expression to
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* internal format.
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*
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* Either meta symbols (\a \d or \p) or character strings or
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* operations ( alternation or perenthesizing ) can be
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* specified. Each starts with a descriptor byte. The descriptor
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* byte has STR set for strings, META set for meta symbols
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* and OPER set for operations.
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* The descriptor byte can also have the OPT bit set if the object
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* defined is optional. Also ALT can be set to indicate an alternation.
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*
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* For metasymbols the byte following the descriptor byte identities
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* the meta symbol (containing an ascii 'a', 'd', 'p', '|', or '('). For
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* strings the byte after the descriptor is a character count for
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* the string:
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*
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* meta symbols := descriptor
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* symbol
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*
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* strings := descriptor
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* character count
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* the string
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*
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* operatins := descriptor
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* symbol
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* character count
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*/
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/*
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* handy macros for accessing parts of match blocks
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*/
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#define MSYM(A) (*(A+1)) /* symbol in a meta symbol block */
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#define MNEXT(A) (A+2) /* character following a metasymbol block */
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#define OSYM(A) (*(A+1)) /* symbol in an operation block */
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#define OCNT(A) (*(A+2)) /* character count */
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#define ONEXT(A) (A+3) /* next character after the operation */
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#define OPTR(A) (A+*(A+2)) /* place pointed to by the operator */
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#define SCNT(A) (*(A+1)) /* byte count of a string */
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#define SSTR(A) (A+2) /* address of the string */
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#define SNEXT(A) (A+2+*(A+1)) /* character following the string */
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/*
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* bit flags in the descriptor
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*/
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#define OPT 1
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#define STR 2
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#define META 4
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#define ALT 8
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#define OPER 16
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static char *ccre; /* pointer to current position in converted exp*/
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static char *ure; /* pointer current position in unconverted exp */
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/* re: unconverted irregular expression */
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char *
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convexp(char *re)
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{
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register char *cre; /* pointer to converted regular expression */
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/* allocate room for the converted expression */
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if (re == NULL)
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return (NULL);
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if (*re == '\0')
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return (NULL);
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cre = malloc(4 * strlen(re) + 3);
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ccre = cre;
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ure = re;
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/* start the conversion with a \a */
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*cre = META | OPT;
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MSYM(cre) = 'a';
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ccre = MNEXT(cre);
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/* start the conversion (its recursive) */
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expconv ();
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*ccre = 0;
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return (cre);
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}
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static void
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expconv()
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{
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register char *cs; /* pointer to current symbol in converted exp */
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register char c; /* character being processed */
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register char *acs; /* pinter to last alternate */
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register int temp;
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/* let the conversion begin */
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acs = NULL;
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cs = NULL;
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while (*ure) {
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switch (c = *ure++) {
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case '\\':
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switch (c = *ure++) {
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/* escaped characters are just characters */
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default:
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if (cs == NULL || (*cs & STR) == 0) {
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cs = ccre;
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*cs = STR;
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SCNT(cs) = 1;
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ccre += 2;
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} else
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SCNT(cs)++;
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*ccre++ = c;
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break;
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/* normal(?) metacharacters */
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case 'a':
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case 'd':
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case 'e':
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case 'p':
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if (acs != NULL && acs != cs) {
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do {
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temp = OCNT(acs);
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OCNT(acs) = ccre - acs;
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acs -= temp;
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} while (temp != 0);
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acs = NULL;
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}
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cs = ccre;
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*cs = META;
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MSYM(cs) = c;
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ccre = MNEXT(cs);
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break;
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}
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break;
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/* just put the symbol in */
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case '^':
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case '$':
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if (acs != NULL && acs != cs) {
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do {
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temp = OCNT(acs);
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OCNT(acs) = ccre - acs;
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acs -= temp;
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} while (temp != 0);
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acs = NULL;
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}
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cs = ccre;
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*cs = META;
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MSYM(cs) = c;
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ccre = MNEXT(cs);
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break;
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/* mark the last match sequence as optional */
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case '?':
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if (cs)
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*cs = *cs | OPT;
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break;
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/* recurse and define a subexpression */
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case '(':
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if (acs != NULL && acs != cs) {
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do {
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temp = OCNT(acs);
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OCNT(acs) = ccre - acs;
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acs -= temp;
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} while (temp != 0);
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acs = NULL;
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}
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cs = ccre;
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*cs = OPER;
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OSYM(cs) = '(';
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ccre = ONEXT(cs);
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expconv();
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OCNT(cs) = ccre - cs; /* offset to next symbol */
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break;
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/* return from a recursion */
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case ')':
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if (acs != NULL) {
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do {
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temp = OCNT(acs);
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OCNT(acs) = ccre - acs;
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acs -= temp;
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} while (temp != 0);
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acs = NULL;
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}
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cs = ccre;
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*cs = META;
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MSYM(cs) = c;
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ccre = MNEXT(cs);
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return;
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/* mark the last match sequence as having an alternate */
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/* the third byte will contain an offset to jump over the */
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/* alternate match in case the first did not fail */
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case '|':
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if (acs != NULL && acs != cs)
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OCNT(ccre) = ccre - acs; /* make a back pointer */
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else
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OCNT(ccre) = 0;
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*cs |= ALT;
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cs = ccre;
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*cs = OPER;
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OSYM(cs) = '|';
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ccre = ONEXT(cs);
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acs = cs; /* remember that the pointer is to be filles */
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break;
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/* if its not a metasymbol just build a scharacter string */
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default:
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if (cs == NULL || (*cs & STR) == 0) {
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cs = ccre;
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*cs = STR;
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SCNT(cs) = 1;
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ccre = SSTR(cs);
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} else
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SCNT(cs)++;
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*ccre++ = c;
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break;
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}
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}
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if (acs != NULL) {
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do {
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temp = OCNT(acs);
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OCNT(acs) = ccre - acs;
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acs -= temp;
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} while (temp != 0);
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acs = NULL;
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}
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return;
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}
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/* end of convertre */
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/*
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* The following routine recognises an irregular expression
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* with the following special characters:
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*
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* \? - means last match was optional
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* \a - matches any number of characters
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* \d - matches any number of spaces and tabs
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* \p - matches any number of alphanumeric
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* characters. The
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* characters matched will be copied into
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* the area pointed to by 'name'.
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* \| - alternation
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* \( \) - grouping used mostly for alternation and
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* optionality
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*
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* The irregular expression must be translated to internal form
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* prior to calling this routine
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*
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* The value returned is the pointer to the first non \a
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* character matched.
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*/
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/*
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* s: string to check for a match in
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* re: a converted irregular expression
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* mstring: where to put whatever matches a \p
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*/
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char *
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expmatch (register char *s, register char *re, register char *mstring)
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{
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register char *cs; /* the current symbol */
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register char *ptr,*s1; /* temporary pointer */
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bool matched; /* a temporary bool */
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/* initial conditions */
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if (re == NULL)
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return (NULL);
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cs = re;
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matched = false;
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/* loop till expression string is exhausted (or at least pretty tired) */
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while (*cs) {
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switch (*cs & (OPER | STR | META)) {
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/* try to match a string */
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case STR:
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matched = !STRNCMP (s, SSTR(cs), SCNT(cs));
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if (matched) {
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/* hoorah it matches */
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s += SCNT(cs);
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cs = SNEXT(cs);
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} else if (*cs & ALT) {
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/* alternation, skip to next expression */
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cs = SNEXT(cs);
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} else if (*cs & OPT) {
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/* the match is optional */
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cs = SNEXT(cs);
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matched = 1; /* indicate a successful match */
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} else {
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/* no match, error return */
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return (NULL);
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}
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break;
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/* an operator, do something fancy */
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case OPER:
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switch (OSYM(cs)) {
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/* this is an alternation */
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case '|':
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if (matched)
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/* last thing in the alternation was a match, skip ahead */
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cs = OPTR(cs);
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else
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/* no match, keep trying */
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cs = ONEXT(cs);
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break;
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/* this is a grouping, recurse */
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case '(':
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ptr = expmatch(s, ONEXT(cs), mstring);
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if (ptr != NULL) {
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/* the subexpression matched */
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matched = 1;
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s = ptr;
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} else if (*cs & ALT) {
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/* alternation, skip to next expression */
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matched = 0;
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} else if (*cs & OPT) {
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/* the match is optional */
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matched = 1; /* indicate a successful match */
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} else {
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/* no match, error return */
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return (NULL);
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}
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cs = OPTR(cs);
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break;
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}
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break;
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/* try to match a metasymbol */
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case META:
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switch (MSYM(cs)) {
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/* try to match anything and remember what was matched */
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case 'p':
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/*
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* This is really the same as trying the match the
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* remaining parts of the expression to any subset
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* of the string.
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*/
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s1 = s;
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do {
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ptr = expmatch(s1, MNEXT(cs), mstring);
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if (ptr != NULL && s1 != s) {
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/* we have a match, remember the match */
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strncpy (mstring, s, s1 - s);
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mstring[s1 - s] = '\0';
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return (ptr);
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} else if (ptr != NULL && (*cs & OPT)) {
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/* it was aoptional so no match is ok */
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return (ptr);
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} else if (ptr != NULL) {
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/* not optional and we still matched */
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return (NULL);
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}
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if (!(isalnum(*s1) || *s1 == '_' ||
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/* C++ destructor */
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*s1 == '~' ||
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/* C++ scope operator */
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(strlen(s1) > 1 && *s1 == ':' && s1[1] == ':' &&
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(s1++, true))))
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return (NULL);
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if (*s1 == '\\')
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_escaped = _escaped ? false : true;
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else
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_escaped = false;
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} while (*s1++);
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return (NULL);
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/* try to match anything */
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case 'a':
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/*
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* This is really the same as trying the match the
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* remaining parts of the expression to any subset
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* of the string.
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*/
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s1 = s;
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do {
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ptr = expmatch(s1, MNEXT(cs), mstring);
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if (ptr != NULL && s1 != s) {
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/* we have a match */
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return (ptr);
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} else if (ptr != NULL && (*cs & OPT)) {
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/* it was aoptional so no match is ok */
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return (ptr);
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} else if (ptr != NULL) {
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/* not optional and we still matched */
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return (NULL);
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}
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if (*s1 == '\\')
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_escaped = _escaped ? false : true;
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else
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_escaped = false;
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} while (*s1++);
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return (NULL);
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/* fail if we are currently _escaped */
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case 'e':
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if (_escaped)
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return(NULL);
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cs = MNEXT(cs);
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break;
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/* match any number of tabs and spaces */
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case 'd':
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ptr = s;
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while (*s == ' ' || *s == '\t')
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s++;
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if (s != ptr || s == s_start) {
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/* match, be happy */
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matched = 1;
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cs = MNEXT(cs);
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} else if (*s == '\n' || *s == '\0') {
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/* match, be happy */
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matched = 1;
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cs = MNEXT(cs);
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} else if (*cs & ALT) {
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/* try the next part */
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matched = 0;
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cs = MNEXT(cs);
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} else if (*cs & OPT) {
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/* doesn't matter */
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matched = 1;
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cs = MNEXT(cs);
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} else
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/* no match, error return */
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return (NULL);
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break;
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/* check for end of line */
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case '$':
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if (*s == '\0' || *s == '\n') {
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/* match, be happy */
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s++;
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matched = 1;
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cs = MNEXT(cs);
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} else if (*cs & ALT) {
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/* try the next part */
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matched = 0;
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cs = MNEXT(cs);
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} else if (*cs & OPT) {
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/* doesn't matter */
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matched = 1;
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cs = MNEXT(cs);
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} else
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/* no match, error return */
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return (NULL);
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break;
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/* check for start of line */
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case '^':
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if (s == s_start) {
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/* match, be happy */
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matched = 1;
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cs = MNEXT(cs);
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} else if (*cs & ALT) {
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/* try the next part */
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matched = 0;
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cs = MNEXT(cs);
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} else if (*cs & OPT) {
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/* doesn't matter */
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matched = 1;
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cs = MNEXT(cs);
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} else
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/* no match, error return */
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return (NULL);
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break;
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/* end of a subexpression, return success */
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case ')':
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return (s);
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}
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break;
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}
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}
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|
return (s);
|
|
}
|