cmd_regex_verifier

crv.cpp

/* Commandline Regular Expression (regex) Verifier Tool
* This tool finds the first partial match in the regex's capture group 1 in the string and pipes it to stdout and exits 0 on success.
* Parameter 1 is the string to search, e.g., "C:\Some\Directory\with\a\special\file_unique12354.exe"
* Parameter 2 is the regex, e.g., "\\.+(thing to find after last backslash, like `name`).+$"
* which would be written like, "\\.+\\.+(unique.+)\."
* From CMD.exe>call crv.exe "C:\Some\Directory\with\a\special\file_unique12354.exe" "\\.+\\.+(unique.+)\."
* That would pipe unique12354 to STDOUT and exit 0.
*/

#include <iostream>
#include <regex>
#include <string>

using namespace std;

static int parseParameters(int arg_counter, char * args[]);

/*=======================================================================================================================================================*/

int main(int argc, char * argv[])
{
	int parameter_check = parseParameters(argc, argv);
	if (parameter_check != 0) { return parameter_check; }

	string regex_string = argv[2];
	const string this_string = string(argv[1]);
	const regex this_regex(regex_string);
	smatch match;

	if (regex_search(this_string.begin(), this_string.end(), match, this_regex))
	{
		cout << match[1] << endl;
		return 0;
	}

	return 1;
}

/*=======================================================================================================================================================*/

static int parseParameters(int arg_counter, char * args[])
{
	int return_code = 0;

	if (arg_counter == 2)
	{
		string this_arg = args[1];
		if ((this_arg == "?") || (this_arg == "/?") || (this_arg == "help") || (this_arg == "-help") || (this_arg == "--help") || (this_arg == "-h"))
		{
			return_code = 2;
		}
		else
		{
			cout << "\nIncorrect parameters sent to " << args[0] << endl;
			return_code = 1;
		}
	}
	else if (arg_counter < 3)
	{
		cout << "\nIncorrect parameters sent to " << args[0] << endl;
		return_code = 1;
	}

	if (return_code != 0)
	{
		cout << "\n===== " << args[0] << " HELP =====" << endl;
		cout << "\nThe first parameter should be the string to search through." << endl;
		cout << "The second parameter should be the regular expression to use against the string." << endl;
		cout << "For example, you would call this program at commandline like so: " << args[0] << " \"This is my string\" " << "\"my (string$)\"" << endl;
		cout << "If there is a regex match, it will print to console the first match it finds and exit 0." << endl;
		cout << "If no match is found, it will print nothing and exit -1." << endl;
		cout << "Returning multiple matches falls outside the scope of this utility's intent." << endl;
		cout << "If this was called with incorrect parameters, it will print this help and exit 1." << endl;
		cout << "If the help was successfully queried with a typical help parameter, it will print this help and exit 2.\n" << endl;
		cout << "Exiting " << args[0] << "..." << endl;
	}

	return return_code;
};