From 102992da75edfcb671eb408bd801703a3f9137d0 Mon Sep 17 00:00:00 2001
From: Jon Bergli Heier <snakebite@jvnv.net>
Date: Wed, 5 Jan 2011 00:23:40 +0100
Subject: Replaced regex parser in telnet::Connection::parse_args() with a
 spirit-based parser.

---
 telnet_connection.cpp | 43 +++++++++++++++++--------------------------
 telnet_connection.h   |  2 +-
 2 files changed, 18 insertions(+), 27 deletions(-)

diff --git a/telnet_connection.cpp b/telnet_connection.cpp
index 8d6675d..9eeecdf 100644
--- a/telnet_connection.cpp
+++ b/telnet_connection.cpp
@@ -3,11 +3,12 @@
 
 #include <boost/bind.hpp>
 #include <boost/algorithm/string.hpp>
-#include <boost/algorithm/string/regex.hpp>
-#include <boost/format.hpp>
+#include <boost/spirit/include/qi.hpp>
 
 #include <iostream>
 
+namespace qi = boost::spirit::qi;
+
 telnet::Connection::Connection(boost::asio::io_service& io_service) : socket(io_service) {
 }
 
@@ -25,9 +26,10 @@ void telnet::Connection::handle_read(const boost::system::error_code& error, siz
 		return;
 	}
 
-	std::vector<std::string> args = parse_args(line);
-	// no arguments, i.e. empty line
-	if(!args.size()) {
+	std::vector<std::string> args;
+
+	// failed to parse or no arguments, i.e. empty line
+	if(!parse_args(line, args) || !args.size()) {
 		start();
 		return;
 	}
@@ -54,27 +56,16 @@ void telnet::Connection::handle_read(const boost::system::error_code& error, siz
 /** Parse a given line and return a vector with its arguments.
  *  Arguments which are surrounded by "quotes" are interpreted as a single argument.
  */
-std::vector<std::string> telnet::Connection::parse_args(std::string& line) {
-	std::string::const_iterator begin = line.begin();
-	std::string::const_iterator end = line.end();
-
-	boost::regex re("(\")?((?(1)[^\"]|[^ ])+)(?(1)\")");
-	boost::match_results<std::string::const_iterator> what;
-	boost::match_flag_type flags = boost::match_default;
-
-	std::vector<std::string> args;
-
-	while(boost::regex_search(begin, end, what, re, flags)) {
-		std::string s = std::string(what[2].first, what[2].second);
-		boost::algorithm::trim(s);
-		// avoid empty strings when parsing multi-word arguments (a "b c")
-		if(s.size()) {
-			args.push_back(s);
-		}
-		begin = what[0].second;
-	}
-
-	return args;
+bool telnet::Connection::parse_args(std::string& line, std::vector<std::string>& args) {
+	std::string::const_iterator begin = line.begin(), end = line.end();
+
+	return qi::parse(begin, end,
+		// find "words in quotes"
+		(('"' >> *(qi::char_ - '"') >> '"') |
+		// single words
+		*(qi::char_ - ' ')) %
+		// skip spaces between arguments
+		+qi::char_(' '), args);
 }
 
 void telnet::Connection::start() {
diff --git a/telnet_connection.h b/telnet_connection.h
index 68d652e..2109b05 100644
--- a/telnet_connection.h
+++ b/telnet_connection.h
@@ -16,7 +16,7 @@ namespace telnet {
 		private:
 			Connection(boost::asio::io_service& io_service);
 			void handle_read(const boost::system::error_code& error, size_t bytes_transferred);
-			std::vector<std::string> parse_args(std::string& line);
+			bool parse_args(std::string& line, std::vector<std::string>& args);
 			tcp::socket socket;
 			boost::asio::streambuf buf;
 
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