std_regex.C

#include "std_regex.H"
#include "args.H"
#include "error.H"

#include <stddef.h>
#include <string.h>

namespace {

    std::regex::flag_type grammarFromString(std::string const & grammar)
    {
        if (grammar.empty() || grammar == "extended") {
            return std::regex::extended;
        }
        else if (grammar == "ECMAScript") {
            return std::regex::ECMAScript;
        }
        else if (grammar == "basic") {
            return std::regex::basic;
        }
        else if (grammar == "awk") {
            return std::regex::awk;
        }
        else if (grammar == "grep") {
            return std::regex::grep;
        }
        else if (grammar == "egrep") {
            return std::regex::egrep;
        }
        else {
            // Fall-back is extended
            return std::regex::extended;
        }
    }
}

Regex::Regex(String const & r, std::string const & grammar)
    : _valid(false)
{
    auto flags = grammarFromString(grammar);
	try {
		if (r.noCase()) {
			flags |= std::regex::icase;
		}
		_preg = std::regex(r, flags);
		_valid = true;
	}
	catch (std::regex_error const& ex) {
		throw Error(ex.what());
	}
}

Regex::~Regex() = default;

bool Regex::match(std::string const & s, Match * pmatch) const
{
    bool rval = false;
    if (_valid) {
		if (pmatch != nullptr) {
			rval = std::regex_search(s, pmatch->smatch(), _preg);
		}
		else {
			rval = std::regex_search(s, _preg);
		}
    }
    return rval;
}