sysrap/tests/match.cc

0001 // name=match ; gcc $name.cc -lstdc++ -o /tmp/$name && /tmp/$name
0002
0003 #include <cassert>
0004
0005 /**
0006 match
0007 -------
0008
0009 Based on https://www.geeksforgeeks.org/wildcard-character-matching/
0010
0011 The second argument string can contain wildcard tokens:
0012
0013 `*`
0014      matches with 0 or more of any char (NB '**' not supported)
0015 `?`
0016      matches any one character.
0017 `$`
0018      when appearing at end of q signifies the end of s
0019
0020 **/
0021
0022 bool match(const char* s, const char* q) // q may contain wildcard chars ? *
0023 {
0024     if (*q == '\0' && *s == '\0') return true;
0025
0026     if (*q == '*' && *(q+1) != '\0' && *s == '\0') return false;  // reached end of s but still q chars coming
0027
0028     if (*q == '$' && *(q+1) == '\0' && *s == '\0' ) return true ;
0029
0030     if (*q == '?' || *q == *s) return match(s+1, q+1);  // on to next char
0031
0032     if (*q == '*') return match(s, q+1) || match(s+1, q);  // '*' can match nothing or anything in s, including literal '*'
0033
0034     return false;
0035 }
0036
0037 int main()
0038 {
0039     assert( match("hello", "hello" ));
0040     assert( match("hello", "he*llo" ));  // '*' matches nothing
0041     assert( match("hello", "hello*" ));
0042     assert( match("hello", "hell*" ));
0043     assert( match("hello", "hell?" ));
0044     assert( match("hello", "?????" ));
0045     assert( match("hello", "?ell?" ));
0046     assert( match("hello", "he?lo" ));
0047     assert( match("hello", "he*" ));
0048     assert( match("hello", "he*lo" ));
0049
0050     assert(!match("hello", "????" ));
0051
0052     assert( match("he*lo", "he*lo" ));
0053     assert( match("he*lo", "he*lo" ));
0054
0055     assert( match("hello", "hello$")) ;
0056     assert( !match("helloworld", "hello$")) ;
0057
0058 }
0059