代码之美 短小精悍的正则表达式匹配器
支持的元字符有'^', '$', '.', '*',beautiful
代码
int matchhere(char* regexp, char* text)
{
if (regexp[0] == '\0')
return 1;
if (regexp[1] == '*')
return matchstar(regexp[0], regexp+2, text);
if (regexp[0] == '$' && regexp[1] == '\0')
return *text = '\0';
if (*text != '\0' && (regexp[0] == '.' || regexp[0] == *text))
return matchhere(regexp+1, text+1);
return 0;
}
int matchstar(char c, char *regexp, char *text)
{
do {
if (matchhere(regexp, text))
return 1;
} while (*text != '\0' && (*text++ == c || c == '.'));
return 0;
}
int match(char *regexp, char *text)
{
if (regexp[0] == '^')
return matchhere(regexp+1,text);
do {
if (matchhere(regexp, text))
return 1;
} while (*text++ != '\0');
return 0;
}
{
if (regexp[0] == '\0')
return 1;
if (regexp[1] == '*')
return matchstar(regexp[0], regexp+2, text);
if (regexp[0] == '$' && regexp[1] == '\0')
return *text = '\0';
if (*text != '\0' && (regexp[0] == '.' || regexp[0] == *text))
return matchhere(regexp+1, text+1);
return 0;
}
int matchstar(char c, char *regexp, char *text)
{
do {
if (matchhere(regexp, text))
return 1;
} while (*text != '\0' && (*text++ == c || c == '.'));
return 0;
}
int match(char *regexp, char *text)
{
if (regexp[0] == '^')
return matchhere(regexp+1,text);
do {
if (matchhere(regexp, text))
return 1;
} while (*text++ != '\0');
return 0;
}