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/** (c) 2000 Jakob Borg
**
** This file implements a sort-of general config-file parser.
** At the moment it only understands key=value pairs, optionally with quoted
** values key="foo bar".
** Keys and unquoted values may not contain spaces.
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
**
** $Id: parser.cc,v 1.3 2000/10/22 20:03:43 jb Exp $
**/
#include <iostream>
#include <fstream>
using namespace std;
#include "parser.h"
/**
** Load a config-file and parse it fully.
** (public)
**/
Config* Parser::parse(string filename)
{
Config* c = new Config();
ifstream file;
file.open(filename.c_str());
unsigned lineno = 0;
while (!file.eof() && !file.bad()) {
unsigned n;
string temp;
getline(file, temp);
lineno++;
if ((n = temp.find_first_of("#")) != string::npos)
temp = temp.substr(0, n);
if (temp.find_first_not_of(" \t") != string::npos)
parse_line(temp, lineno, c);
}
file.close();
return c;
}
/**
** Parse a line
** (private)
**/
void Parser::parse_line(string line, unsigned lineno, Config* c)
{
try {
line = subparse_line(line);
} catch (string s) {
cerr << "Parse error on line " << lineno
<< " of config file: \"" << s << "\"." << endl;
return;
}
// there can be no error here; the string is already confirmed to be correct
unsigned n = line.find_first_of("=");
c->set_value(line.substr(0, n), line.substr(n + 1));
}
/**
** Remove trailing and leading whitespace, as well as around the '='.
** With error checking.
** (private)
**/
string Parser::subparse_line(string s)
{
string tmp;
unsigned state = 0;
for (string::const_iterator i = s.begin(); i != s.end(); i++) {
switch (state) {
case 0: // leading space
if (!isspace(*i)) {
tmp.push_back(*i);
state = 1;
}
break;
case 1: // keyname
if (*i == '=') {
tmp.push_back(*i);
state = 2;
} else if (!isspace(*i))
tmp.push_back(*i);
else
state = 6;
break;
case 6: // after space after keyname
if (*i == '=') {
tmp.push_back(*i);
state = 2;
} else if (isspace(*i))
throw(string("illegal space in key name"));
break;
case 2: // after '='
if (*i == '"')
state = 4;
else if (!isspace(*i)) {
tmp.push_back(*i);
state = 3;
}
break;
case 3: // inside unquoted value;
if (*i == '"')
throw(string("illegal loose quote in value"));
else if (isspace(*i))
state = 5;
else
tmp.push_back(*i);
break;
case 4: // inside quoted value
if (*i == '"')
state = 5;
else
tmp.push_back(*i);
break;
case 5: // after value
if (!isspace(*i))
throw(string("garbage after end of value (need quotes?)"));
break;
}
}
if (state != 5 && state != 3)
throw(string("unexpected end of line"));
return tmp;
}
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