Split the HTTP GET query string into the parameters.

query_parser.cpp

#include <map>
#include <string>
#include <iostream>

using namespace std;

/**
 * Split the HTTP GET query string into the parameters.
 * 
 * e.g. 
 * input = "test1=12345&test2=56789"
 * output = {
 *    "test1" => "12345",
 *    "test2" => "56789"
 * }
 * 
 * @args   query  - query string. 
 * @return result - Hash map key and values.
 * 
 * @author Junpei Tsuji (@tsujimotter)
 * @lastupdate 2013/01/04
 * 
 */ 
map<string, string> query_parser(const string &query)
{
	string str = query;
	map<string, string> result;
	int cutAt;

	while( (cutAt = str.find_first_of("&")) != str.npos )
	{
		if(cutAt > 0)
		{
			string entry = str.substr(0, cutAt);
			
			int c;
			if( (c = entry.find_first_of("=")) != entry.npos )
			{
				string key   = entry.substr(0, c);
				string value = entry.substr(c + 1);
				result.insert( map<string, string>::value_type( key, value ) );
			}	
		}
		str = str.substr(cutAt + 1);
	}
	if(str.length() > 0)
	{
		int c;
		if( (c = str.find_first_of("=")) != str.npos )
		{
			string key   = str.substr(0, c);
			string value = str.substr(c + 1);
			result.insert( map<string, string>::value_type( key, value ) );
		}
		
	}
	return result;	
}