op_regex.h

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#ifndef OP_REGEX_H
#define OP_REGEX_H

// required by posix before including regex.h
#include <sys/types.h>
#include <regex.h>

#include <string>
#include <vector>
#include <map>

#include "op_exception.h"

struct bad_regex : op_exception {
    bad_regex(std::string const & pattern);
};

class regular_expression_replace {
public:
    regular_expression_replace(size_t limit = 100,
                   size_t limit_defs_expansion = 100);
    ~regular_expression_replace();

    void add_definition(std::string const & name,
                std::string const & replace);
    void add_pattern(std::string const & pattern,
             std::string const & replace);

    bool execute(std::string & str) const;
private:
    struct replace_t {
        // when this regexp is matched
        regex_t regexp;
        // replace the matched part with this string
        std::string replace;
    };

    // helper to execute
    bool do_execute(std::string & str, replace_t const & regexp) const;
    void do_replace(std::string & str, std::string const & replace,
            regmatch_t const * match) const;

    // helper to add_definition() and add_pattern()
    std::string expand_string(std::string const & input);

    // helper to add_pattern
    std::string substitute_definition(std::string const & pattern);

    // return the match of throw if idx is invalid
    regmatch_t const & get_match(regmatch_t const * match, char idx) const;

    // don't increase too, it have direct impact on performance. This limit
    // the number of grouping expression allowed in a regular expression
    // Note than you can use grouping match operator > 9 only in the
    // replace rule not in match regular expression since POSIX don't allow
    // more than \9 in matching sequence.
    static const size_t max_match = 16;

    size_t limit;
    size_t limit_defs_expansion;
    std::vector<replace_t> regex_replace;
    typedef std::map<std::string, std::string> defs_dict;
    defs_dict defs;
};

void setup_regex(regular_expression_replace& regex,
         std::string const & filename);

#endif /* !OP_REGEX_H */