fmtmatch.c revision 34f9b3eef6fdadbda0a846aa4d68691ac40eace5
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2009 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* Glenn Fowler
* AT&T Research
*
* return strmatch() expression given REG_AUGMENTED RE
* 0 returned for invalid RE
*/
#include <ast.h>
char*
{
register char* s = (char*)as;
register int c;
register char* t;
register char** p;
register char* b;
char* x;
char* y;
char* z;
int a;
int e;
int n;
char* buf;
char* stack[32];
t = b = buf + 3;
p = stack;
if (a = *s == '^')
s++;
e = 0;
for (;;)
{
switch (c = *s++)
{
case 0:
break;
case '\\':
if (!(c = *s++))
return 0;
switch (*s)
{
case '*':
case '+':
case '?':
*t++ = *s++;
*t++ = '(';
*t++ = '\\';
*t++ = c;
c = ')';
break;
case '|':
case '&':
if (c == '(')
{
*t++ = c;
c = *s++;
goto logical;
}
break;
case '{':
case '}':
break;
default:
*t++ = '\\';
break;
}
*t++ = c;
continue;
case '[':
x = t;
*t++ = c;
if ((c = *s++) == '^')
{
*t++ = '!';
c = *s++;
}
else if (c == '!')
{
*t++ = '\\';
*t++ = c;
c = *s++;
}
for (;;)
{
if (!(*t++ = c))
return 0;
if (c == '\\')
*t++ = c;
if ((c = *s++) == ']')
{
*t++ = c;
break;
}
}
switch (*s)
{
case '*':
case '+':
case '?':
for (y = t + 2, t--; t >= x; t--)
*(t + 2) = *t;
*++t = *s++;
*++t = '(';
t = y;
*t++ = ')';
break;
}
continue;
case '(':
return 0;
*p++ = t;
if (*s == '?')
{
s++;
if (*s == 'K' && *(s + 1) == ')')
{
s += 2;
p--;
while (*t = *s)
t++, s++;
continue;
}
*t++ = '~';
}
else
*t++ = '@';
*t++ = '(';
continue;
case ')':
if (p == stack)
return 0;
p--;
*t++ = c;
switch (*s)
{
case 0:
break;
case '*':
case '+':
case '?':
case '!':
**p = *s++;
if (*s == '?')
{
s++;
x = *p + 1;
for (y = ++t; y > x; y--)
*y = *(y - 1);
*x = '-';
}
continue;
case '{':
for (z = s; *z != '}'; z++)
if (!*z)
return 0;
n = z - s;
if (*++z == '?')
n++;
x = *p + n;
for (y = t += n; y > x; y--)
*y = *(y - n);
for (x = *p; s < z; *x++ = *s++);
if (*s == '?')
{
s++;
*x++ = '-';
}
continue;
default:
continue;
}
break;
case '.':
switch (*s)
{
case 0:
*t++ = '?';
break;
case '*':
s++;
*t++ = '*';
e = !*s;
continue;
case '+':
s++;
*t++ = '?';
*t++ = '*';
continue;
case '?':
s++;
*t++ = '?';
*t++ = '(';
*t++ = '?';
*t++ = ')';
continue;
default:
*t++ = '?';
continue;
}
break;
case '*':
case '+':
case '?':
case '{':
n = *(t - 1);
if (t == b || n == '(' || n == '|')
return 0;
*(t - 1) = c;
if (c == '{')
{
for (z = s; *z != '}'; z++)
if (!*z)
return 0;
for (; s <= z; *t++ = *s++);
}
if (*s == '?')
{
s++;
*t++ = '-';
}
*t++ = '(';
*t++ = n;
*t++ = ')';
continue;
case '|':
case '&':
if (t == b || *(t - 1) == '(')
return 0;
if (!*s || *s == ')')
return 0;
{
*--b = '(';
*--b = '@';
}
*t++ = c;
continue;
case '$':
if (e = !*s)
break;
/*FALLTHROUGH*/
default:
*t++ = c;
continue;
}
break;
}
if (p != stack)
return 0;
if (b != buf + 3)
*t++ = ')';
if (!a && (*b != '*' || *(b + 1) == '(' || (*(b + 1) == '-' || *(b + 1) == '~') && *(b + 2) == '('))
*--b = '*';
if (!e)
*t++ = '*';
*t = 0;
return b;
}