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rexp3.c
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rexp3.c
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/********************************************
rexp3.c
copyright 2008-2009,2010, Thomas E. Dickey
copyright 2010, Jonathan Nieder
copyright 1991-1992,1993, Michael D. Brennan
This is a source file for mawk, an implementation of
the AWK programming language.
Mawk is distributed without warranty under the terms of
the GNU General Public License, version 2, 1991.
********************************************/
/*
* $MawkId: rexp3.c,v 1.26 2010/07/21 23:06:24 tom Exp $
* @Log: rexp3.c,v @
* Revision 1.3 1993/07/24 17:55:15 mike
* more cleanup
*
* Revision 1.2 1993/07/23 13:21:48 mike
* cleanup rexp code
*
* Revision 1.1.1.1 1993/07/03 18:58:28 mike
* move source to cvs
*
* Revision 3.6 1992/12/24 00:44:53 mike
* fixed potential LMDOS bozo with M_STR+U_ON+END_ON
* fixed minor bug in M_CLASS+U_ON+END_ON
*
* Revision 3.5 1992/01/21 17:33:20 brennan
* added some casts so that character classes work with signed chars
*
* Revision 3.4 91/10/29 10:54:09 brennan
* SIZE_T
*
* Revision 3.3 91/08/13 09:10:18 brennan
* VERSION .9994
*
* Revision 3.2 91/06/10 16:18:17 brennan
* changes for V7
*
* Revision 3.1 91/06/07 10:33:28 brennan
* VERSION 0.995
*
* Revision 1.4 91/05/31 10:56:32 brennan
* stack_empty hack for DOS large model
*
*/
/* match a string against a machine */
#include "rexp.h"
#define push(mx,sx,px,ssx,ux) do { \
if (++stackp == RE_run_stack_limit) \
stackp = RE_new_run_stack() ;\
stackp->m = (mx); \
stackp->s = (sx); \
stackp->sp = (int) ((px) - RE_pos_stack_base); \
stackp->tp = (px)->prev_offset; \
stackp->ss = (ssx); \
stackp->u = (ux); \
} while(0)
#define CASE_UANY(x) case x + U_OFF : case x + U_ON
/* returns start of first longest match and the length by
reference. If no match returns NULL and length zero */
char *
REmatch(char *str, /* string to test */
size_t str_len, /* ...its length */
PTR machine, /* compiled regular expression */
size_t *lenp) /* where to return matched-length */
{
register STATE *m = (STATE *) machine;
char *s = str;
char *ss;
register RT_STATE *stackp;
int u_flag, t;
char *str_end = s + str_len;
RT_POS_ENTRY *sp;
char *ts;
/* state of current best match stored here */
char *cb_ss; /* the start */
char *cb_e = 0; /* the end , pts at first char not matched */
STATE *m_best = 0;
*lenp = 0;
/* check for the easy case */
if ((m + 1)->s_type == M_ACCEPT && m->s_type == M_STR) {
if ((ts = str_str(s, str_len, m->s_data.str, (size_t) m->s_len)))
*lenp = m->s_len;
return ts;
}
u_flag = U_ON;
cb_ss = ss = (char *) 0;
stackp = RE_run_stack_empty;
sp = RE_pos_stack_empty;
goto reswitch;
refill:
if (stackp == RE_run_stack_empty) {
if (cb_ss)
*lenp = (unsigned) (cb_e - cb_ss);
return cb_ss;
}
ss = stackp->ss;
s = (stackp--)->s;
if (cb_ss) { /* does new state start too late ? */
if (ss) {
if (cb_ss < ss || (cb_ss == ss && cb_e == str_end)) {
goto refill;
}
} else if (cb_ss < s || (cb_ss == s && cb_e == str_end)) {
goto refill;
}
}
m = (stackp + 1)->m;
sp = RE_pos_stack_base + (stackp + 1)->sp;
sp->prev_offset = (stackp + 1)->tp;
u_flag = (stackp + 1)->u;
reswitch:
switch (m->s_type + u_flag) {
case M_STR + U_OFF + END_OFF:
if (strncmp(s, m->s_data.str, (size_t) m->s_len)) {
goto refill;
}
if (!ss) {
if (cb_ss && s > cb_ss) {
goto refill;
} else {
ss = s;
}
}
s += m->s_len;
m++;
goto reswitch;
case M_STR + U_OFF + END_ON:
if (strcmp(s, m->s_data.str)) {
goto refill;
}
if (!ss) {
if (cb_ss && s > cb_ss) {
goto refill;
} else {
ss = s;
}
}
s += m->s_len;
m++;
goto reswitch;
case M_STR + U_ON + END_OFF:
if (s >= str_end) {
goto refill;
}
if (!(s = str_str(s, (size_t) (str_end - s), m->s_data.str, (size_t) m->s_len))) {
goto refill;
}
if (s >= str + strlen(str)) {
goto refill;
}
push(m, s + 1, sp, ss, U_ON);
if (!ss) {
if (cb_ss && s > cb_ss) {
goto refill;
} else {
ss = s;
}
}
s += m->s_len;
m++;
u_flag = U_OFF;
goto reswitch;
case M_STR + U_ON + END_ON:
t = (int) ((str_end - s) - m->s_len);
if (t < 0 || memcmp(ts = s + t, m->s_data.str, (size_t) m->s_len)) {
goto refill;
}
if (!ss) {
if (cb_ss && ts > cb_ss) {
goto refill;
} else {
ss = ts;
}
}
s = str_end;
m++;
u_flag = U_OFF;
goto reswitch;
case M_CLASS + U_OFF + END_OFF:
if (s >= str_end)
goto refill;
if (!ison(*m->s_data.bvp, s[0])) {
goto refill;
}
if (!ss) {
if (cb_ss && s > cb_ss) {
goto refill;
} else {
ss = s;
}
}
s++;
m++;
goto reswitch;
case M_CLASS + U_OFF + END_ON:
if (s >= str_end)
goto refill;
if (s[1] || !ison(*m->s_data.bvp, s[0])) {
goto refill;
}
if (!ss) {
if (cb_ss && s > cb_ss) {
goto refill;
} else {
ss = s;
}
}
s++;
m++;
goto reswitch;
case M_CLASS + U_ON + END_OFF:
if (s >= str_end)
goto refill;
while (!ison(*m->s_data.bvp, s[0])) {
if (s >= str_end) {
goto refill;
} else {
s++;
}
}
if (s >= str_end) {
goto refill;
}
s++;
push(m, s, sp, ss, U_ON);
if (!ss) {
if (cb_ss && s - 1 > cb_ss) {
goto refill;
} else {
ss = s - 1;
}
}
m++;
u_flag = U_OFF;
goto reswitch;
case M_CLASS + U_ON + END_ON:
if ((s >= str_end) || !ison(*m->s_data.bvp, str_end[-1])) {
goto refill;
}
if (!ss) {
if (cb_ss && str_end - 1 > cb_ss) {
goto refill;
} else {
ss = str_end - 1;
}
}
s = str_end;
m++;
u_flag = U_OFF;
goto reswitch;
case M_ANY + U_OFF + END_OFF:
if (s >= str_end) {
goto refill;
}
if (!ss) {
if (cb_ss && s > cb_ss) {
goto refill;
} else {
ss = s;
}
}
s++;
m++;
goto reswitch;
case M_ANY + U_OFF + END_ON:
if ((s >= str_end) || ((s + 1) < str_end)) {
goto refill;
}
if (!ss) {
if (cb_ss && s > cb_ss) {
goto refill;
} else {
ss = s;
}
}
s++;
m++;
goto reswitch;
case M_ANY + U_ON + END_OFF:
if (s >= str_end) {
goto refill;
}
s++;
push(m, s, sp, ss, U_ON);
if (!ss) {
if (cb_ss && s - 1 > cb_ss) {
goto refill;
} else {
ss = s - 1;
}
}
m++;
u_flag = U_OFF;
goto reswitch;
case M_ANY + U_ON + END_ON:
if (s >= str_end) {
goto refill;
}
if (!ss) {
if (cb_ss && str_end - 1 > cb_ss) {
goto refill;
} else {
ss = str_end - 1;
}
}
s = str_end;
m++;
u_flag = U_OFF;
goto reswitch;
case M_START + U_OFF + END_OFF:
case M_START + U_ON + END_OFF:
if (s != str) {
goto refill;
}
ss = s;
m++;
u_flag = U_OFF;
goto reswitch;
case M_START + U_OFF + END_ON:
case M_START + U_ON + END_ON:
if (s != str || (s < str_end)) {
goto refill;
}
ss = s;
m++;
u_flag = U_OFF;
goto reswitch;
case M_END + U_OFF:
if (s < str_end) {
goto refill;
}
if (!ss) {
if (cb_ss && s > cb_ss) {
goto refill;
} else {
ss = s;
}
}
m++;
goto reswitch;
case M_END + U_ON:
s = str_end;
if (!ss) {
if (cb_ss && s > cb_ss) {
goto refill;
} else {
ss = s;
}
}
m++;
u_flag = U_OFF;
goto reswitch;
CASE_UANY(M_U):
if (!ss) {
if (cb_ss && s > cb_ss) {
goto refill;
} else {
ss = s;
}
}
u_flag = U_ON;
m++;
goto reswitch;
CASE_UANY(M_1J):
m += m->s_data.jump;
goto reswitch;
CASE_UANY(M_SAVE_POS): /* save position for a later M_2JC */
/* see also REtest */
sp = RE_pos_push(sp, stackp, s);
m++;
goto reswitch;
CASE_UANY(M_2JA): /* take the non jump branch */
push(m + m->s_data.jump, s, sp, ss, u_flag);
m++;
goto reswitch;
CASE_UANY(M_2JC): /* take the jump branch if position changed */
/* see REtest */
if (RE_pos_pop(&sp, stackp) == s) {
m++;
goto reswitch;
}
/* fall thru */
CASE_UANY(M_2JB): /* take the jump branch */
push(m + 1, s, sp, ss, u_flag);
m += m->s_data.jump;
goto reswitch;
case M_ACCEPT + U_OFF:
if (!ss)
ss = s;
if (!cb_ss || ss < cb_ss || (ss == cb_ss && s > cb_e)) {
/* we have a new current best */
cb_ss = ss;
cb_e = s;
m_best = m;
}
goto refill;
case M_ACCEPT + U_ON:
if (!ss) {
ss = s;
} else {
s = str_end;
}
if (!cb_ss || ss < cb_ss || (ss == cb_ss && s > cb_e)) {
/* we have a new current best */
cb_ss = ss;
cb_e = s;
m_best = m;
}
goto refill;
default:
RE_panic("unexpected case in REmatch");
}
}
#undef push