src/common/rexpr.c

#ifndef lint
static const char       RCSid[] = "$Id: rexpr.c,v 2.7 2003/06/07 12:50:20 schorsch Exp $";
#endif
/*
 * Regular expression parsing routines.
 *
 * External symbols declared in standard.h
 */

#include "copyright.h"

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>

/*
 * rexpr.c - regular expression parser (ala grep)
 */

#define CCHR    2
#define CDOT    4
#define CCL     6
#define NCCL    8
#define CDOL    10
#define CEOF    11
#define CBRC    14
#define CLET    15
#define STAR    01

#define ESIZE   255

#define same(a,b) (a==b || (iflag && (a^b)==' ' && isalpha(a)))


static int     advance(), cclass();

static char    expbuf[ESIZE];
static int     iflag;
static int     circf;

int     explen;                 /* length of the last expression found */

int
ecompile(sp, iflg, wflag)               /* compile the expression */
register char  *sp;
int iflg, wflag;
{
        register c;
        register char *ep;
        char *lastep;
        int cclcnt;
        
        iflag = iflg;
        ep = expbuf;
        explen = 0;
        if (*sp == '^') {
                circf = 1;
                sp++;
        } else
                circf = 0;
        if (wflag)
                *ep++ = CBRC;
        for (;;) {
                if (ep >= &expbuf[ESIZE])
                        return(-1);
                if ((c = *sp++) != '*')
                        lastep = ep;
                switch (c) {

                case '\0':
                        if (wflag)
                                *ep++ = CLET;
                        *ep++ = CEOF;
                        explen = ep - expbuf;
                        return(0);

                case '.':
                        *ep++ = CDOT;
                        continue;

                case '*':
                        if (lastep==0)
                                goto defchar;
                        *lastep |= STAR;
                        continue;

                case '$':
                        if (*sp != '\0')
                                goto defchar;
                        *ep++ = CDOL;
                        continue;

                case '[':
                        *ep++ = CCL;
                        *ep++ = 0;
                        cclcnt = 1;
                        if ((c = *sp++) == '^') {
                                c = *sp++;
                                ep[-2] = NCCL;
                        }
                        do {
                                *ep++ = c;
                                cclcnt++;
                                if (c=='\0' || ep >= &expbuf[ESIZE])
                                        return(-1);
                        } while ((c = *sp++) != ']');
                        lastep[1] = cclcnt;
                        continue;

                case '\\':
                        if ((c = *sp++) == '\0')
                                return(-1);
                        if (c == '<') {
                                if (ep == expbuf || ep[-1] != CBRC)
                                        *ep++ = CBRC;
                                continue;
                        }
                        if (c == '>') {
                                *ep++ = CLET;
                                continue;
                        }
                defchar:
                default:
                        *ep++ = CCHR;
                        *ep++ = c;
                }
        }
}

char *
expsave()                     /* save compiled string */
{
        register char  *ep;

        if (explen == 0)
                return(NULL);
        if ((ep = (char *)malloc(explen+3)) == NULL)
                return(NULL);
        ep[0] = iflag;
        ep[1] = circf;
        ep[2] = explen;
        (void)memcpy(ep+3, expbuf, explen);
        return(ep);
}

void
expset(ep)                      /* install saved string */
register char  *ep;
{
        iflag = ep[0];
        circf = ep[1];
        (void)memcpy(expbuf, ep+3, ep[2]&0xff);
}

char *
eindex(sp)                    /* find the expression in string sp */
register char *sp;
{
        /* check for match at beginning of line, watch CBRC */
        if (advance(sp, expbuf[0]==CBRC ? expbuf+1 : expbuf))
                return(sp);
        if (circf)
                return(NULL);
        /* fast check for first character */
        if (expbuf[0]==CCHR) {
                register c = expbuf[1];
                while (*++sp)
                        if (same(*sp, c) && advance(sp, expbuf))
                                return(sp);
                return(NULL);
        }
        /* regular algorithm */
        while (*++sp)
                if (advance(sp, expbuf))
                        return(sp);
        return(NULL);
}

static int
advance(alp, ep)
        char *alp;
register char *ep;
{
        register char *lp;
        char *curlp;

        lp = alp;
        for (;;) switch (*ep++) {

        case CCHR:
                if (!same(*ep, *lp))
                        return (0);
                ep++, lp++;
                continue;

        case CDOT:
                if (*lp++)
                        continue;
                return(0);

        case CDOL:
                if (*lp==0)
                        continue;
                return(0);

        case CEOF:
                explen = lp - alp;
                return(1);

        case CCL:
                if (cclass(ep, *lp++, 1)) {
                        ep += *ep;
                        continue;
                }
                return(0);

        case NCCL:
                if (cclass(ep, *lp++, 0)) {
                        ep += *ep;
                        continue;
                }
                return(0);

        case CDOT|STAR:
                curlp = lp;
                while (*lp++);
                goto star;

        case CCHR|STAR:
                curlp = lp;
                while (same(*lp, *ep))
                        lp++;
                lp++;
                ep++;
                goto star;

        case CCL|STAR:
        case NCCL|STAR:
                curlp = lp;
                while (cclass(ep, *lp++, ep[-1]==(CCL|STAR)));
                ep += *ep;
        star:
                do {
                        lp--;
                        if (advance(lp, ep)) {
                                explen += lp - alp;
                                return(1);
                        }
                } while (lp > curlp);
                return(0);

        case CBRC:
                if ((isalnum(*lp) || *lp == '_') && !(isalnum(lp[-1]) || lp[-1] == '_'))
                        continue;
                return (0);

        case CLET:
                if (!isalnum(*lp) && *lp != '_')
                        continue;
                return (0);

        default:
                fprintf(stderr, "RE botch\n");
        }
}

static int
cclass(set, c, af)
register char *set;
register c;
int af;
{
        register n;

        if (c == 0)
                return(0);
        n = *set++;
        while (--n)
                if (n > 2 && set[1] == '-') {
                        if (c >= set[0] && c <= set[2])
                                return (af);
                        set += 3;
                        n -= 2;
                } else
                        if (*set++ == c)
                                return(af);
        return(!af);
}
Revision:	2.8
Committed:	Mon Jun 30 14:59:11 2003 UTC (20 years, 10 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 2.7:	+1 -4 lines
Log Message:	Replaced most outdated BSD function calls with their posix equivalents, and cleaned up a few other platform dependencies.
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	schorsch	2.8	static const char RCSid[] = "$Id: rexpr.c,v 2.7 2003/06/07 12:50:20 schorsch Exp $";
3	greg	1.1	#endif
4	greg	2.4	/*
5			* Regular expression parsing routines.
6			*
7			* External symbols declared in standard.h
8			*/
9
10	greg	2.5	#include "copyright.h"
11	greg	1.1
12			#include <stdio.h>
13	greg	2.4	#include <stdlib.h>
14	greg	1.1	#include <ctype.h>
15	schorsch	2.7	#include <string.h>
16
17	greg	1.1	/*
18			* rexpr.c - regular expression parser (ala grep)
19			*/
20
21			#define CCHR 2
22			#define CDOT 4
23			#define CCL 6
24			#define NCCL 8
25			#define CDOL 10
26			#define CEOF 11
27			#define CBRC 14
28			#define CLET 15
29			#define STAR 01
30
31			#define ESIZE 255
32
33			#define same(a,b) (a==b \|\| (iflag && (a^b)==' ' && isalpha(a)))
34
35	greg	1.2
36	greg	1.4	static int advance(), cclass();
37
38	greg	1.1	static char expbuf[ESIZE];
39			static int iflag;
40			static int circf;
41
42			int explen; /* length of the last expression found */
43
44			int
45			ecompile(sp, iflg, wflag) /* compile the expression */
46			register char *sp;
47			int iflg, wflag;
48			{
49			register c;
50			register char *ep;
51			char *lastep;
52			int cclcnt;
53
54			iflag = iflg;
55			ep = expbuf;
56			explen = 0;
57			if (*sp == '^') {
58			circf = 1;
59			sp++;
60			} else
61			circf = 0;
62			if (wflag)
63			*ep++ = CBRC;
64			for (;;) {
65			if (ep >= &expbuf[ESIZE])
66			return(-1);
67			if ((c = sp++) != '')
68			lastep = ep;
69			switch (c) {
70
71			case '\0':
72			if (wflag)
73			*ep++ = CLET;
74			*ep++ = CEOF;
75			explen = ep - expbuf;
76			return(0);
77
78			case '.':
79			*ep++ = CDOT;
80			continue;
81
82			case '*':
83			if (lastep==0)
84			goto defchar;
85			*lastep \|= STAR;
86			continue;
87
88			case '$':
89			if (*sp != '\0')
90			goto defchar;
91			*ep++ = CDOL;
92			continue;
93
94			case '[':
95			*ep++ = CCL;
96			*ep++ = 0;
97			cclcnt = 1;
98			if ((c = *sp++) == '^') {
99			c = *sp++;
100			ep[-2] = NCCL;
101			}
102			do {
103			*ep++ = c;
104			cclcnt++;
105			if (c=='\0' \|\| ep >= &expbuf[ESIZE])
106			return(-1);
107			} while ((c = *sp++) != ']');
108			lastep[1] = cclcnt;
109			continue;
110
111			case '\\':
112			if ((c = *sp++) == '\0')
113			return(-1);
114			if (c == '<') {
115	greg	2.2	if (ep == expbuf \|\| ep[-1] != CBRC)
116			*ep++ = CBRC;
117	greg	1.1	continue;
118			}
119			if (c == '>') {
120			*ep++ = CLET;
121			continue;
122			}
123			defchar:
124			default:
125			*ep++ = CCHR;
126			*ep++ = c;
127			}
128			}
129			}
130
131			char *
132			expsave() /* save compiled string */
133			{
134			register char *ep;
135
136			if (explen == 0)
137			return(NULL);
138	greg	2.4	if ((ep = (char *)malloc(explen+3)) == NULL)
139	greg	1.1	return(NULL);
140			ep[0] = iflag;
141			ep[1] = circf;
142			ep[2] = explen;
143			(void)memcpy(ep+3, expbuf, explen);
144			return(ep);
145			}
146
147	greg	2.4	void
148	greg	1.1	expset(ep) /* install saved string */
149			register char *ep;
150			{
151			iflag = ep[0];
152			circf = ep[1];
153			(void)memcpy(expbuf, ep+3, ep[2]&0xff);
154			}
155
156			char *
157	greg	2.2	eindex(sp) /* find the expression in string sp */
158	greg	1.1	register char *sp;
159			{
160	greg	2.2	/* check for match at beginning of line, watch CBRC */
161			if (advance(sp, expbuf[0]==CBRC ? expbuf+1 : expbuf))
162			return(sp);
163			if (circf)
164	greg	1.1	return(NULL);
165			/* fast check for first character */
166			if (expbuf[0]==CCHR) {
167			register c = expbuf[1];
168	greg	2.2	while (*++sp)
169	greg	1.1	if (same(*sp, c) && advance(sp, expbuf))
170			return(sp);
171			return(NULL);
172			}
173			/* regular algorithm */
174	greg	2.2	while (*++sp)
175	greg	1.1	if (advance(sp, expbuf))
176			return(sp);
177			return(NULL);
178			}
179
180			static int
181			advance(alp, ep)
182			char *alp;
183			register char *ep;
184			{
185			register char *lp;
186			char *curlp;
187
188			lp = alp;
189			for (;;) switch (*ep++) {
190
191			case CCHR:
192			if (!same(ep, lp))
193			return (0);
194			ep++, lp++;
195			continue;
196
197			case CDOT:
198			if (*lp++)
199			continue;
200			return(0);
201
202			case CDOL:
203			if (*lp==0)
204			continue;
205			return(0);
206
207			case CEOF:
208			explen = lp - alp;
209			return(1);
210
211			case CCL:
212			if (cclass(ep, *lp++, 1)) {
213			ep += *ep;
214			continue;
215			}
216			return(0);
217
218			case NCCL:
219			if (cclass(ep, *lp++, 0)) {
220			ep += *ep;
221			continue;
222			}
223			return(0);
224
225			case CDOT\|STAR:
226			curlp = lp;
227			while (*lp++);
228			goto star;
229
230			case CCHR\|STAR:
231			curlp = lp;
232			while (same(lp, ep))
233			lp++;
234			lp++;
235			ep++;
236			goto star;
237
238			case CCL\|STAR:
239			case NCCL\|STAR:
240			curlp = lp;
241			while (cclass(ep, *lp++, ep[-1]==(CCL\|STAR)));
242			ep += *ep;
243			star:
244			do {
245			lp--;
246			if (advance(lp, ep)) {
247			explen += lp - alp;
248			return(1);
249			}
250			} while (lp > curlp);
251			return(0);
252
253			case CBRC:
254			if ((isalnum(lp) \|\| lp == '_') && !(isalnum(lp[-1]) \|\| lp[-1] == '_'))
255			continue;
256			return (0);
257
258			case CLET:
259			if (!isalnum(lp) && lp != '_')
260			continue;
261			return (0);
262
263			default:
264			fprintf(stderr, "RE botch\n");
265			}
266			}
267
268			static int
269			cclass(set, c, af)
270			register char *set;
271			register c;
272	greg	2.3	int af;
273	greg	1.1	{
274			register n;
275
276			if (c == 0)
277			return(0);
278			n = *set++;
279			while (--n)
280			if (n > 2 && set[1] == '-') {
281			if (c >= set[0] && c <= set[2])
282			return (af);
283			set += 3;
284			n -= 2;
285			} else
286			if (*set++ == c)
287			return(af);
288			return(!af);
289			}