[unix-history] / usr / src / usr.bin / vgrind / regexp.c

static char sccsid[] = "@(#)regexp.c	4.1	(Berkeley)	%G%";

#include <ctype.h>

typedef int	boolean;
#define TRUE	1
#define FALSE	0
#define NIL	0

boolean l_onecase;	/* true if upper and lower equivalent */

#define makelower(c) (isupper((c)) ? tolower((c)) : (c))

/*  STRNCMP -	like strncmp except that we convert the
 *	 	first string to lower case before comparing
 *		if l_onecase is set.
 */

STRNCMP(s1, s2, len)
	register char *s1,*s2;
	register int len;
{
	if (l_onecase) {
	    do
		if (*s2 - makelower(*s1))
			return (*s2 - makelower(*s1));
		else {
			s2++;
			s1++;
		}
	    while (--len);
	} else {
	    do
		if (*s2 - *s1)
			return (*s2 - *s1);
		else {
			s2++;
			s1++;
		}
	    while (--len);
	}
	return(0);
}

/*	The following routine converts an irregular expression to
 *	internal format.
 *
 *	Either meta symbols (\a \d or \p) or character strings or
 *	operations ( alternation or perenthesizing ) can be
 *	specified.  Each starts with a descriptor byte.  The descriptor
 *	byte has STR set for strings, META set for meta symbols
 *	and OPER set for operations.
 *	The descriptor byte can also have the OPT bit set if the object
 *	defined is optional.  Also ALT can be set to indicate an alternation.
 *
 *	For metasymbols the byte following the descriptor byte identities
 *	the meta symbol (containing an ascii 'a', 'd', 'p', '|', or '(').  For
 *	strings the byte after the descriptor is a character count for
 *	the string:
 *
 *		meta symbols := descriptor
 *				symbol
 *
 *		strings :=	descriptor
 *				character count
 *				the string
 *
 *		operatins :=	descriptor
 *				symbol
 *				character count
 */

/*
 *  handy macros for accessing parts of match blocks
 */
#define MSYM(A) (*(A+1))	/* symbol in a meta symbol block */
#define MNEXT(A) (A+2)		/* character following a metasymbol block */

#define OSYM(A) (*(A+1))	/* symbol in an operation block */
#define OCNT(A) (*(A+2))	/* character count */
#define ONEXT(A) (A+3)		/* next character after the operation */
#define OPTR(A) (A+*(A+2))	/* place pointed to by the operator */

#define SCNT(A) (*(A+1))	/* byte count of a string */
#define SSTR(A) (A+2)		/* address of the string */
#define SNEXT(A) (A+2+*(A+1))	/* character following the string */

/*
 *  bit flags in the descriptor 
 */
#define OPT 1
#define STR 2
#define META 4
#define ALT 8
#define OPER 16

char *ure;		/* pointer current position in unconverted exp */
char *ccre;		/* pointer to current position in converted exp*/
char *malloc();

char *
convexp(re)
    char *re;		/* unconverted irregular expression */
{
    register char *cre;		/* pointer to converted regular expression */

    /* allocate room for the converted expression */
    if (re == NIL)
	return (NIL);
    if (*re == '\0')
	return (NIL);
    cre = malloc (4 * strlen(re) + 3);
    ccre = cre;
    ure = re;

    /* start the conversion with a \a */
    *cre = META | OPT;
    MSYM(cre) = 'a';
    ccre = MNEXT(cre);

    /* start the conversion (its recursive) */
    expconv ();
    *ccre = 0;
    return (cre);
}

expconv()
{
    register char *cs;		/* pointer to current symbol in converted exp */
    register char c;		/* character being processed */
    register char *acs;		/* pinter to last alternate */
    register int temp;

    /* let the conversion begin */
    acs = NIL;
    while (*ure != NIL) {
	switch (c = *ure++) {

	case '\\':
	    switch (c = *ure++) {

	    /* escaped characters are just characters */
	    default:
		if ((*cs & STR) == 0) {
		    cs = ccre;
		    *cs = STR;
		    SCNT(cs) = 1;
		    ccre += 2;
		} else 
		    SCNT(cs)++;
		*ccre++ = c;
		break;

	    /* normal(?) metacharacters */
	    case 'a':
	    case 'd':
	    case 'e':
	    case 'p':
		if (acs != NIL && acs != cs) {
		    do {
			temp = OCNT(acs);
			OCNT(acs) = ccre - acs; 
			acs -= temp;
		    } while (temp != 0);
		    acs = NIL;
		}
		cs = ccre;
		*cs = META;
		MSYM(cs) = c;
		ccre = MNEXT(cs);
		break;
	    }
	    break;
	    
	/* just put the symbol in */
	case '^':
	case '$':
	    if (acs != NIL && acs != cs) {
		do {
		    temp = OCNT(acs);
		    OCNT(acs) = ccre - acs;
		    acs -= temp;
		} while (temp != 0);
		acs = NIL;
	    }
	    cs = ccre;
	    *cs = META;
	    MSYM(cs) = c;
	    ccre = MNEXT(cs);
	    break;

	/* mark the last match sequence as optional */
	case '?':
	    *cs = *cs | OPT;
	    break;

	/* recurse and define a subexpression */
	case '(':
	    if (acs != NIL && acs != cs) {
		do {
		    temp = OCNT(acs);
		    OCNT(acs) = ccre - acs;
		    acs -= temp;
		} while (temp != 0);
		acs = NIL;
	    }
	    cs = ccre;
	    *cs = OPER;
	    OSYM(cs) = '(';
	    ccre = ONEXT(cs);
	    expconv ();
	    OCNT(cs) = ccre - cs;		/* offset to next symbol */
	    break;

	/* return from a recursion */
	case ')':
	    if (acs != NIL) {
		do {
		    temp = OCNT(acs);
		    OCNT(acs) = ccre - acs;
		    acs -= temp;
		} while (temp != 0);
		acs = NIL;
	    }
	    cs = ccre;
	    *cs = META;
	    MSYM(cs) = c;
	    ccre = MNEXT(cs);
	    return;

	/* mark the last match sequence as having an alternate */
	/* the third byte will contain an offset to jump over the */
	/* alternate match in case the first did not fail */
	case '|':
	    if (acs != NIL && acs != cs)
		OCNT(ccre) = ccre - acs;	/* make a back pointer */
	    else
		OCNT(ccre) = 0;
	    *cs |= ALT;
	    cs = ccre;
	    *cs = OPER;
	    OSYM(cs) = '|';
	    ccre = ONEXT(cs);
	    acs = cs;	/* remember that the pointer is to be filles */
	    break;

	/* if its not a metasymbol just build a scharacter string */
	default:
	    if ((*cs & STR) == 0) {
		cs = ccre;
		*cs = STR;
		SCNT(cs) = 1;
		ccre = SSTR(cs);
	    } else
		SCNT(cs)++;
	    *ccre++ = c;
	    break;
	}
    }
    if (acs != NIL) {
	do {
	    temp = OCNT(acs);
	    OCNT(acs) = ccre - acs;
	    acs -= temp;
	} while (temp != 0);
	acs = NIL;
    }
    return;
}
/* end of convertre */


/*
 *	The following routine recognises an irregular expresion
 *	with the following special characters:
 *
 *		\?	-	means last match was optional
 *		\a	-	matches any number of characters
 *		\d	-	matches any number of spaces and tabs
 *		\p	-	matches any number of alphanumeric
 *				characters. The
 *				characters matched will be copied into
 *				the area pointed to by 'name'.
 *		\|	-	alternation
 *		\( \)	-	grouping used mostly for alternation and
 *				optionality
 *
 *	The irregular expression must be translated to internal form
 *	prior to calling this routine
 *
 *	The value returned is the pointer to the first non \a 
 *	character matched.
 */

boolean _escaped;		/* true if we are currently _escaped */
char *_start;			/* start of string */

char *
expmatch (s, re, mstring)
    register char *s;		/* string to check for a match in */
    register char *re;		/* a converted irregular expression */
    register char *mstring;	/* where to put whatever matches a \p */
{
    register char *cs;		/* the current symbol */
    register char *ptr,*s1;	/* temporary pointer */
    boolean matched;		/* a temporary boolean */

    /* initial conditions */
    if (re == NIL)
	return (NIL);
    cs = re;
    matched = FALSE;

    /* loop till expression string is exhausted (or at least pretty tired) */
    while (*cs) {
	switch (*cs & (OPER | STR | META)) {

	/* try to match a string */
	case STR:
	    matched = !STRNCMP (s, SSTR(cs), SCNT(cs));
	    if (matched) {

		/* hoorah it matches */
		s += SCNT(cs);
		cs = SNEXT(cs);
	    } else if (*cs & ALT) {

		/* alternation, skip to next expression */
		cs = SNEXT(cs);
	    } else if (*cs & OPT) {

		/* the match is optional */
		cs = SNEXT(cs);
		matched = 1;		/* indicate a successful match */
	    } else {

		/* no match, error return */
		return (NIL);
	    }
	    break;

	/* an operator, do something fancy */
	case OPER:
	    switch (OSYM(cs)) {

	    /* this is an alternation */
	    case '|':
		if (matched)

		    /* last thing in the alternation was a match, skip ahead */
		    cs = OPTR(cs);
		else

		    /* no match, keep trying */
		    cs = ONEXT(cs);
		break;

	    /* this is a grouping, recurse */
	    case '(':
		ptr = expmatch (s, ONEXT(cs), mstring);
		if (ptr != NIL) {

		    /* the subexpression matched */
		    matched = 1;
		    s = ptr;
		} else if (*cs & ALT) {

		    /* alternation, skip to next expression */
		    matched = 0;
		} else if (*cs & OPT) {

		    /* the match is optional */
		    matched = 1;	/* indicate a successful match */
		} else {

		    /* no match, error return */
		    return (NIL);
		}
		cs = OPTR(cs);
		break;
	    }
	    break;

	/* try to match a metasymbol */
	case META:
	    switch (MSYM(cs)) {

	    /* try to match anything and remember what was matched */
	    case 'p':
		/*
		 *  This is really the same as trying the match the
		 *  remaining parts of the expression to any subset
		 *  of the string.
		 */
		s1 = s;
		do {
		    ptr = expmatch (s1, MNEXT(cs), mstring);
		    if (ptr != NIL && s1 != s) {

			/* we have a match, remember the match */
			strncpy (mstring, s, s1 - s);
			mstring[s1 - s] = '\0';
			return (ptr);
		    } else if (ptr != NIL && (*cs & OPT)) {

			/* it was aoptional so no match is ok */
			return (ptr);
		    } else if (ptr != NIL) {

			/* not optional and we still matched */
			return (NIL);
		    }
		    if (!isalnum(*s1) && *s1 != '_')
			return (NIL);
		    if (*s1 == '\\')
			_escaped = _escaped ? FALSE : TRUE;
		    else
			_escaped = FALSE;
		} while (*s1++);
		return (NIL);

	    /* try to match anything */
	    case 'a':
		/*
		 *  This is really the same as trying the match the
		 *  remaining parts of the expression to any subset
		 *  of the string.
		 */
		s1 = s;
		do {
		    ptr = expmatch (s1, MNEXT(cs), mstring);
		    if (ptr != NIL && s1 != s) {

			/* we have a match */
			return (ptr);
		    } else if (ptr != NIL && (*cs & OPT)) {

			/* it was aoptional so no match is ok */
			return (ptr);
		    } else if (ptr != NIL) {

			/* not optional and we still matched */
			return (NIL);
		    }
		    if (*s1 == '\\')
			_escaped = _escaped ? FALSE : TRUE;
		    else
			_escaped = FALSE;
		} while (*s1++);
		return (NIL);

	    /* fail if we are currently _escaped */
	    case 'e':
		if (_escaped)
		    return(NIL);
		cs = MNEXT(cs); 
		break;

	    /* match any number of tabs and spaces */
	    case 'd':
		ptr = s;
		while (*s == ' ' || *s == '\t')
		    s++;
		if (s != ptr || s == _start) {

		    /* match, be happy */
		    matched = 1;
		    cs = MNEXT(cs); 
		} else if (*s == '\n' || *s == '\0') {

		    /* match, be happy */
		    matched = 1;
		    cs = MNEXT(cs); 
		} else if (*cs & ALT) {

		    /* try the next part */
		    matched = 0;
		    cs = MNEXT(cs);
		} else if (*cs & OPT) {

		    /* doesn't matter */
		    matched = 1;
		    cs = MNEXT(cs);
		} else

		    /* no match, error return */
		    return (NIL);
		break;

	    /* check for end of line */
	    case '$':
		if (*s == '\0' || *s == '\n') {

		    /* match, be happy */
		    s++;
		    matched = 1;
		    cs = MNEXT(cs);
		} else if (*cs & ALT) {

		    /* try the next part */
		    matched = 0;
		    cs = MNEXT(cs);
		} else if (*cs & OPT) {

		    /* doesn't matter */
		    matched = 1;
		    cs = MNEXT(cs);
		} else

		    /* no match, error return */
		    return (NIL);
		break;

	    /* check for start of line */
	    case '^':
		if (s == _start) {

		    /* match, be happy */
		    matched = 1;
		    cs = MNEXT(cs);
		} else if (*cs & ALT) {

		    /* try the next part */
		    matched = 0;
		    cs = MNEXT(cs);
		} else if (*cs & OPT) {

		    /* doesn't matter */
		    matched = 1;
		    cs = MNEXT(cs);
		} else

		    /* no match, error return */
		    return (NIL);
		break;

	    /* end of a subexpression, return success */
	    case ')':
		return (s);
	    }
	    break;
	}
    }
    return (s);
}
Commit	Line	Data
23e9541a KM	1	static char sccsid[] = "@(#)regexp.c 4.1 (Berkeley) %G%";
	2
	3	#include <ctype.h>
	4
	5	typedef int boolean;
	6	#define TRUE 1
	7	#define FALSE 0
	8	#define NIL 0
	9
	10	boolean l_onecase; /* true if upper and lower equivalent */
	11
	12	#define makelower(c) (isupper((c)) ? tolower((c)) : (c))
	13
	14	/* STRNCMP - like strncmp except that we convert the
	15	* first string to lower case before comparing
	16	* if l_onecase is set.
	17	*/
	18
	19	STRNCMP(s1, s2, len)
	20	register char s1,s2;
	21	register int len;
	22	{
	23	if (l_onecase) {
	24	do
	25	if (s2 - makelower(s1))
	26	return (s2 - makelower(s1));
	27	else {
	28	s2++;
	29	s1++;
	30	}
	31	while (--len);
	32	} else {
	33	do
	34	if (s2 - s1)
	35	return (s2 - s1);
	36	else {
	37	s2++;
	38	s1++;
	39	}
	40	while (--len);
	41	}
	42	return(0);
	43	}
	44
	45	/* The following routine converts an irregular expression to
	46	* internal format.
	47	*
	48	* Either meta symbols (\a \d or \p) or character strings or
	49	* operations ( alternation or perenthesizing ) can be
	50	* specified. Each starts with a descriptor byte. The descriptor
	51	* byte has STR set for strings, META set for meta symbols
	52	* and OPER set for operations.
	53	* The descriptor byte can also have the OPT bit set if the object
	54	* defined is optional. Also ALT can be set to indicate an alternation.
	55	*
	56	* For metasymbols the byte following the descriptor byte identities
	57	* the meta symbol (containing an ascii 'a', 'd', 'p', '\|', or '('). For
	58	* strings the byte after the descriptor is a character count for
	59	* the string:
	60	*
	61	* meta symbols := descriptor
	62	* symbol
	63	*
	64	* strings := descriptor
65	* character count
66	* the string
67	*
68	* operatins := descriptor
69	* symbol
70	* character count
71	*/
72
73	/*
74	* handy macros for accessing parts of match blocks
75	*/
76	#define MSYM(A) ((A+1)) / symbol in a meta symbol block */
77	#define MNEXT(A) (A+2) /* character following a metasymbol block */
78
79	#define OSYM(A) ((A+1)) / symbol in an operation block */
80	#define OCNT(A) ((A+2)) / character count */
81	#define ONEXT(A) (A+3) /* next character after the operation */
82	#define OPTR(A) (A+(A+2)) / place pointed to by the operator */
83
84	#define SCNT(A) ((A+1)) / byte count of a string */
85	#define SSTR(A) (A+2) /* address of the string */
86	#define SNEXT(A) (A+2+(A+1)) / character following the string */
87
88	/*
89	* bit flags in the descriptor
90	*/
91	#define OPT 1
92	#define STR 2
93	#define META 4
94	#define ALT 8
95	#define OPER 16
96
97	char ure; / pointer current position in unconverted exp */
98	char ccre; / pointer to current position in converted exp*/
99	char *malloc();
100
101	char *
102	convexp(re)
103	char re; / unconverted irregular expression */
104	{
105	register char cre; / pointer to converted regular expression */
106
107	/* allocate room for the converted expression */
108	if (re == NIL)
109	return (NIL);
110	if (*re == '\0')
111	return (NIL);
112	cre = malloc (4 * strlen(re) + 3);
113	ccre = cre;
114	ure = re;
115
116	/* start the conversion with a \a */
117	*cre = META \| OPT;
118	MSYM(cre) = 'a';
119	ccre = MNEXT(cre);
120
121	/* start the conversion (its recursive) */
122	expconv ();
123	*ccre = 0;
124	return (cre);
125	}
126
127	expconv()
128	{
129	register char cs; / pointer to current symbol in converted exp */
130	register char c; /* character being processed */
131	register char acs; / pinter to last alternate */
132	register int temp;
133
134	/* let the conversion begin */
135	acs = NIL;
136	while (*ure != NIL) {
137	switch (c = *ure++) {
138
139	case '\\':
140	switch (c = *ure++) {
141
142	/* escaped characters are just characters */
143	default:
144	if ((*cs & STR) == 0) {
145	cs = ccre;
146	*cs = STR;
147	SCNT(cs) = 1;
148	ccre += 2;
149	} else
150	SCNT(cs)++;
151	*ccre++ = c;
152	break;
153
154	/* normal(?) metacharacters */
155	case 'a':
156	case 'd':
157	case 'e':
158	case 'p':
159	if (acs != NIL && acs != cs) {
160	do {
161	temp = OCNT(acs);
162	OCNT(acs) = ccre - acs;
163	acs -= temp;
164	} while (temp != 0);
165	acs = NIL;
166	}
167	cs = ccre;
168	*cs = META;
169	MSYM(cs) = c;
170	ccre = MNEXT(cs);
171	break;
172	}
173	break;
174
175	/* just put the symbol in */
176	case '^':
177	case '$':
178	if (acs != NIL && acs != cs) {
179	do {
180	temp = OCNT(acs);
181	OCNT(acs) = ccre - acs;
182	acs -= temp;
183	} while (temp != 0);
184	acs = NIL;
185	}
186	cs = ccre;
187	*cs = META;
188	MSYM(cs) = c;
189	ccre = MNEXT(cs);
190	break;
191
192	/* mark the last match sequence as optional */
193	case '?':
194	cs = cs \| OPT;
195	break;
196
197	/* recurse and define a subexpression */
198	case '(':
199	if (acs != NIL && acs != cs) {
200	do {
201	temp = OCNT(acs);
202	OCNT(acs) = ccre - acs;
203	acs -= temp;
204	} while (temp != 0);
205	acs = NIL;
206	}
207	cs = ccre;
208	*cs = OPER;
209	OSYM(cs) = '(';
210	ccre = ONEXT(cs);
211	expconv ();
212	OCNT(cs) = ccre - cs; /* offset to next symbol */
213	break;
214
215	/* return from a recursion */
216	case ')':
217	if (acs != NIL) {
218	do {
219	temp = OCNT(acs);
220	OCNT(acs) = ccre - acs;
221	acs -= temp;
222	} while (temp != 0);
223	acs = NIL;
224	}
225	cs = ccre;
226	*cs = META;
227	MSYM(cs) = c;
228	ccre = MNEXT(cs);
229	return;
230
231	/* mark the last match sequence as having an alternate */
232	/* the third byte will contain an offset to jump over the */
233	/* alternate match in case the first did not fail */
234	case '\|':
235	if (acs != NIL && acs != cs)
236	OCNT(ccre) = ccre - acs; /* make a back pointer */
237	else
238	OCNT(ccre) = 0;
239	*cs \|= ALT;
240	cs = ccre;
241	*cs = OPER;
242	OSYM(cs) = '\|';
243	ccre = ONEXT(cs);
244	acs = cs; /* remember that the pointer is to be filles */
245	break;
246
247	/* if its not a metasymbol just build a scharacter string */
248	default:
249	if ((*cs & STR) == 0) {
250	cs = ccre;
251	*cs = STR;
252	SCNT(cs) = 1;
253	ccre = SSTR(cs);
254	} else
255	SCNT(cs)++;
256	*ccre++ = c;
257	break;
258	}
259	}
260	if (acs != NIL) {
261	do {
262	temp = OCNT(acs);
263	OCNT(acs) = ccre - acs;
264	acs -= temp;
265	} while (temp != 0);
266	acs = NIL;
267	}
268	return;
269	}
270	/* end of convertre */
271
272
273	/*
274	* The following routine recognises an irregular expresion
275	* with the following special characters:
276	*
277	* \? - means last match was optional
278	* \a - matches any number of characters
279	* \d - matches any number of spaces and tabs
280	* \p - matches any number of alphanumeric
281	* characters. The
282	* characters matched will be copied into
283	* the area pointed to by 'name'.
284	* \\| - alternation
285	* \( \) - grouping used mostly for alternation and
286	* optionality
287	*
288	* The irregular expression must be translated to internal form
289	* prior to calling this routine
290	*
291	* The value returned is the pointer to the first non \a
292	* character matched.
293	*/
294
295	boolean _escaped; /* true if we are currently _escaped */
296	char _start; / start of string */
297
298	char *
299	expmatch (s, re, mstring)
300	register char s; / string to check for a match in */
301	register char re; / a converted irregular expression */
302	register char mstring; / where to put whatever matches a \p */
303	{
304	register char cs; / the current symbol */
305	register char ptr,s1; /* temporary pointer */
306	boolean matched; /* a temporary boolean */
307
308	/* initial conditions */
309	if (re == NIL)
310	return (NIL);
311	cs = re;
312	matched = FALSE;
313
314	/* loop till expression string is exhausted (or at least pretty tired) */
315	while (*cs) {
316	switch (*cs & (OPER \| STR \| META)) {
317
318	/* try to match a string */
319	case STR:
320	matched = !STRNCMP (s, SSTR(cs), SCNT(cs));
321	if (matched) {
322
323	/* hoorah it matches */
324	s += SCNT(cs);
325	cs = SNEXT(cs);
326	} else if (*cs & ALT) {
327
328	/* alternation, skip to next expression */
329	cs = SNEXT(cs);
330	} else if (*cs & OPT) {
331
332	/* the match is optional */
333	cs = SNEXT(cs);
334	matched = 1; /* indicate a successful match */
335	} else {
336
337	/* no match, error return */
338	return (NIL);
339	}
340	break;
341
342	/* an operator, do something fancy */
343	case OPER:
344	switch (OSYM(cs)) {
345
346	/* this is an alternation */
347	case '\|':
348	if (matched)
349
350	/* last thing in the alternation was a match, skip ahead */
351	cs = OPTR(cs);
352	else
353
354	/* no match, keep trying */
355	cs = ONEXT(cs);
356	break;
357
358	/* this is a grouping, recurse */
359	case '(':
360	ptr = expmatch (s, ONEXT(cs), mstring);
361	if (ptr != NIL) {
362
363	/* the subexpression matched */
364	matched = 1;
365	s = ptr;
366	} else if (*cs & ALT) {
367
368	/* alternation, skip to next expression */
369	matched = 0;
370	} else if (*cs & OPT) {
371
372	/* the match is optional */
373	matched = 1; /* indicate a successful match */
374	} else {
375
376	/* no match, error return */
377	return (NIL);
378	}
379	cs = OPTR(cs);
380	break;
381	}
382	break;
383
384	/* try to match a metasymbol */
385	case META:
386	switch (MSYM(cs)) {
387
388	/* try to match anything and remember what was matched */
389	case 'p':
390	/*
391	* This is really the same as trying the match the
392	* remaining parts of the expression to any subset
393	* of the string.
394	*/
395	s1 = s;
396	do {
397	ptr = expmatch (s1, MNEXT(cs), mstring);
398	if (ptr != NIL && s1 != s) {
399
400	/* we have a match, remember the match */
401	strncpy (mstring, s, s1 - s);
402	mstring[s1 - s] = '\0';
403	return (ptr);
404	} else if (ptr != NIL && (*cs & OPT)) {
405
406	/* it was aoptional so no match is ok */
407	return (ptr);
408	} else if (ptr != NIL) {
409
410	/* not optional and we still matched */
411	return (NIL);
412	}
413	if (!isalnum(s1) && s1 != '_')
414	return (NIL);
415	if (*s1 == '\\')
416	_escaped = _escaped ? FALSE : TRUE;
417	else
418	_escaped = FALSE;
419	} while (*s1++);
420	return (NIL);
421
422	/* try to match anything */
423	case 'a':
424	/*
425	* This is really the same as trying the match the
426	* remaining parts of the expression to any subset
427	* of the string.
428	*/
429	s1 = s;
430	do {
431	ptr = expmatch (s1, MNEXT(cs), mstring);
432	if (ptr != NIL && s1 != s) {
433
434	/* we have a match */
435	return (ptr);
436	} else if (ptr != NIL && (*cs & OPT)) {
437
438	/* it was aoptional so no match is ok */
439	return (ptr);
440	} else if (ptr != NIL) {
441
442	/* not optional and we still matched */
443	return (NIL);
444	}
445	if (*s1 == '\\')
446	_escaped = _escaped ? FALSE : TRUE;
447	else
448	_escaped = FALSE;
449	} while (*s1++);
450	return (NIL);
451
452	/* fail if we are currently _escaped */
453	case 'e':
454	if (_escaped)
455	return(NIL);
456	cs = MNEXT(cs);
457	break;
458
459	/* match any number of tabs and spaces */
460	case 'd':
461	ptr = s;
462	while (s == ' ' \|\| s == '\t')
463	s++;
464	if (s != ptr \|\| s == _start) {
465
466	/* match, be happy */
467	matched = 1;
468	cs = MNEXT(cs);
469	} else if (s == '\n' \|\| s == '\0') {
470
471	/* match, be happy */
472	matched = 1;
473	cs = MNEXT(cs);
474	} else if (*cs & ALT) {
475
476	/* try the next part */
477	matched = 0;
478	cs = MNEXT(cs);
479	} else if (*cs & OPT) {
480
481	/* doesn't matter */
482	matched = 1;
483	cs = MNEXT(cs);
484	} else
485
486	/* no match, error return */
487	return (NIL);
488	break;
489
490	/* check for end of line */
491	case '$':
492	if (s == '\0' \|\| s == '\n') {
493
494	/* match, be happy */
495	s++;
496	matched = 1;
497	cs = MNEXT(cs);
498	} else if (*cs & ALT) {
499
500	/* try the next part */
501	matched = 0;
502	cs = MNEXT(cs);
503	} else if (*cs & OPT) {
504
505	/* doesn't matter */
506	matched = 1;
507	cs = MNEXT(cs);
508	} else
509
510	/* no match, error return */
511	return (NIL);
512	break;
513
514	/* check for start of line */
515	case '^':
516	if (s == _start) {
517
518	/* match, be happy */
519	matched = 1;
520	cs = MNEXT(cs);
521	} else if (*cs & ALT) {
522
523	/* try the next part */
524	matched = 0;
525	cs = MNEXT(cs);
526	} else if (*cs & OPT) {
527
528	/* doesn't matter */
529	matched = 1;
530	cs = MNEXT(cs);
531	} else
532
533	/* no match, error return */
534	return (NIL);
535	break;
536
537	/* end of a subexpression, return success */
538	case ')':
539	return (s);
540	}
541	break;
542	}
543	}
544	return (s);
545	}