cegex

This is basic c regex engine.

[!WARNING] This is an educational project, DO NOT USE in prod!

Table of Contents:

Usage

include "cegex.h"


int main(){
    char *regex = "o.w(l|d)+";
         *text  = "hello wldddll abcd!",
    //                 ^ match ^

    //{int index, int length}                v Flags
    CegexValue res = cegex_match(regex, text, NULL);

    // Get matched part from text
    char matched_word[res.length+1];
    memcpy(&matched_word, text + res.index, sizeof(char) * res.length);
    matched_word[res.length] = '\0'; // null terminitaion

    printf("%s\n", matched_word);
    return 0;
}

Supported operations:

symbol	name	description	usage	example	status
`?`	question	zero or one repeat	`a?`	`aa`, `a`	[x]
`*`	kleene star	zero or more repeat	`a*`	`aaa`,	[x]
`+`	plus	one or more repeat	`a+`	`a`, `aa`	[x]
`\|`	pipe	one of right or left	`a\|b`	`a`, `b`	[x]
`.`	dot	any char except new line	`a.`	`aX`	[x]
`\`	escape	for using regex char as a plain text	`a\.`	`a\.`	[x]
`( )`	group	group regex expressions	`(a\|b)+`	`aab`	[x]
`^`	start	regex start here	`^a`	`abcd`	[ ]
`[ ]`	any	any of given chars	`[ab]`	`a`	[ ]
`{ }`	time	multiply char given times	`a{3}`	`aaa`	[ ]
`\d`	decimal	decimal character	`a\d`	`a1`	[ ]
`\D`	not decimal	not a decimal character	`a\D`	`aX`	[ ]
`\w`	word	alphanumerical character	`a\w`	`a?`,`as`	[ ]
`\W`	not word	not alphanumerical character	`a\W`	`a1`	[ ]
`\s`	space	space or tab character	`a\s`	`a` , `a`	[ ]
`\S`	not space	not space character	`a\S`	`a`	[ ]

IMPORTANT NOTE: Currently, we dont backtrace the regex stack so, maybe some operator combinations like a.*b can't correct work.

For example: Normally a.*b matchs with axxxb but cegex doesn't parse like a, .*, b. Cegex's stack loaded like this: a, ., *, b.

Contributing

This project accepts the open source and free software mentality in its main terms. Development and distribution are free within the framework of the rules specified in the license section, BUT the course and mentality of the project depends entirely on my discretion.

Please respect this mentality and contributing rules

License

This project is under the GNU GPLv3 license.

Related Projects

tiny-regex-c

Small portable regex in C

18 Apr 2017 1,216

oniguruma

regular expression library

13 Jul 2015 2,294