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• write a pattern optimiser and call it before invoking do_gmatch(), 

to catch several very slow cases (especially “*@(*foo)” busy-loops
  – spotted by Jb_boin as usual these days ☺) by converting all @(…)
  with one case to drop the enclosing MAGIC(…), and in a second pass
  collapsing adjacent asterisk (‘*’) wildcards
This commit is contained in:
tg 2011-03-17 22:00:45 +00:00
parent a1a5922fc6
commit 2f2fe89157
1 changed files with 88 additions and 4 deletions
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92
misc.c
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@ -29,7 +29,7 @@
#include <grp.h>
#endif
__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.155 2011/03/17 21:59:28 tg Exp $");
__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.156 2011/03/17 22:00:45 tg Exp $");
/* type bits for unsigned char */
unsigned char chtypes[UCHAR_MAX + 1];
@ -486,6 +486,79 @@ bi_getn(const char *as, int *ai)
return (rv);
}
/**
* pattern simplifications:
* - @(x) -> x (not @(x|y) though)
* - ** -> *
*/
static void *
simplify_gmatch_pattern(const unsigned char *sp)
{
uint8_t c;
unsigned char *cp, *dp;
const unsigned char *ps, *se;
cp = alloc(strlen((void *)sp) + 1, ATEMP);
goto simplify_gmatch_pat1a;
/* foo@(b@(a)r)b@(a|a)z -> foobarb@(a|a)z */
simplify_gmatch_pat1:
sp = cp;
simplify_gmatch_pat1a:
dp = cp;
se = sp + strlen((const void *)sp);
while ((c = *sp++)) {
if (!ISMAGIC(c)) {
*dp++ = c;
continue;
}
switch ((c = *sp++)) {
case 0x80|'@':
/* simile for @ */
case 0x80|' ':
/* check whether it has only one clause */
ps = pat_scan(sp, se, true);
if (!ps || ps[-1] != /*(*/ ')')
/* nope */
break;
/* copy inner clause until matching close */
ps -= 2;
while ((const unsigned char *)sp < ps)
*dp++ = *sp++;
/* skip MAGIC and closing parenthesis */
sp += 2;
/* copy the rest of the pattern */
memmove(dp, sp, strlen((void *)sp) + 1);
/* redo from start */
goto simplify_gmatch_pat1;
}
*dp++ = MAGIC;
*dp++ = c;
}
*dp = '\0';
/* collapse adjacent asterisk wildcards */
sp = dp = cp;
while ((c = *sp++)) {
if (!ISMAGIC(c)) {
*dp++ = c;
continue;
}
switch ((c = *sp++)) {
case '*':
while (ISMAGIC(sp[0]) && sp[1] == c)
sp += 2;
break;
}
*dp++ = MAGIC;
*dp++ = c;
}
*dp = '\0';
/* return the result, allocated from ATEMP */
return (cp);
}
/* -------- gmatch.c -------- */
/*
@ -495,11 +568,12 @@ bi_getn(const char *as, int *ai)
* Match a pattern as in sh(1).
* pattern character are prefixed with MAGIC by expand.
*/
int
gmatchx(const char *s, const char *p, bool isfile)
{
const char *se, *pe;
char *pnew;
int rv;
if (s == NULL || p == NULL)
return (0);
@ -517,8 +591,18 @@ gmatchx(const char *s, const char *p, bool isfile)
debunk(t, p, len);
return (!strcmp(t, s));
}
return (do_gmatch((const unsigned char *) s, (const unsigned char *) se,
(const unsigned char *) p, (const unsigned char *) pe));
/*
* since the do_gmatch() engine sucks so much, we must do some
* pattern simplifications
*/
pnew = simplify_gmatch_pattern((const unsigned char *)p);
pe = pnew + strlen(pnew);
rv = do_gmatch((const unsigned char *)s, (const unsigned char *)se,
(const unsigned char *)pnew, (const unsigned char *)pe);
afree(pnew, ATEMP);
return (rv);
}
/**