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varexp.cpp
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varexp.cpp
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include "varexp.h"
/*
copyright (c) 2004, 2006 squell <[email protected]>
use, modification, copying and distribution of this software is permitted
under the conditions described in the file 'COPYING'.
an adapted version of a smaller, simpler wildcard match routine to
support a primitive form of pattern matching
the base C version included at the end, if you're interested
*/
bool varexp::match(const char *mask, const char *test)
{
char c, m;
const char *flag = &c; // dummy value
do {
const char* resume[2] = { flag, };
do {
retry: switch( c=*test++, m=*mask++ ) {
case '\\':
if(!*mask) goto fail;
m = *mask++; // fall thru
default :
if( m != c ) goto fail; // double break
continue;
case '?':
int skip; skip = mblen(test-1, MB_CUR_MAX);
if(skip > 1) test += skip-1;
continue;
case '*':
if(*resume)
flag = 0, var.push_back(pairvec::value_type(test-1, 0));
else
var.back().second++;
resume[0] = mask-1, resume[1] = test;
--test;
goto retry; // forced continue
case '[':
if(! (mask=in_set(c, mask)) ) goto fail;
}
} while(c);
fail: mask = resume[0];
test = resume[1];
} while(c && test);
return !(m|c);
}
/*
auxilliary code to detect character ranges in expressions
uses plain value comparison to detect ranges; not collating sequences.
issue: refuses to compare non-ascii characters in order to avoid
serious problems with UTF-8 strings; varexp should really be lifted
to the wchar_t world.
*/
const char *varexp::in_set(char c, const char *set)
{
const char *start = set;
int neg = 0, truth = 0;
char prev, m;
if(*set=='!' || *set=='^') {
neg = 1; // match chars NOT in set
++set;
}
for(prev = 0; (m = *set++) && !(m & 0x80); prev = m) {
if(m=='-' && prev && *set!='\0' && *set!=']') {
truth |= (c >= prev) && (c <= *set);
} else {
if(m==']')
return (truth^neg)? set : 0;
truth |= (m==c);
}
}
return (c == '[')? start : 0; // not a set notation
}
/*
primitive C version without pattern matching (inefficient)
int match(const char *mask, const char *test)
{
char c, m;
do {
switch( c=*test++, m=*mask++ ) {
default :
if( m != c ) return 0;
case '?':
break;
case '*':
if( match(mask,test-1) ) return 1;
--mask;
}
} while(c);
return !m;
}
non-recursive C version without pattern matching
int match(const char *mask, const char *test)
{
char c, m;
do {
const char* resume[2] = { 0, };
do {
retry: switch( c=*test++, m=*mask++ ) {
default :
if( m != c ) goto fail; // double break
case '?':
continue;
case '*':
resume[0] = mask-1, resume[1] = test;
--test;
goto retry; // forced continue
}
} while(c);
fail: mask = resume[0];
test = resume[1];
} while(c && mask);
return !(m|c);
}
*/