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/*
** PJL C++ Library
** option_stream.c
**
** Copyright (C) 1999 Paul J. Lucas
**
** 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
// standard
#include <algorithm> /* for copy() */
#include <cstdlib> /* for abort(3) */
#include <cstring>
#include <iterator>
#include <iostream>
// local
#include "platform.h"
#include "option_stream.h"
using namespace std;
namespace PJL {
#define ERROR os.err_ << os.argv_[0] << ": error: option "
//*****************************************************************************
//
// SYNOPSIS
//
option_stream::option_stream(
int argc, char *argv[], spec const specs[], ostream &err
)
//
// DESCRIPTION
//
// Construct (initialize) an option_stream.
//
// PARAMETERS
//
// argc The number of arguments.
//
// argv A vector of the arguments; argv[argc] is null.
//
// specs A vector of option specifications, i.e., the options that are
// allowed and their argument parameters.
//
// err The ostream to emit error messages to.
//
//*****************************************************************************
: argc_( argc ), argv_( argv ), specs_( specs ), err_( err ), argi_( 0 ),
next_c_( 0 ), end_( false )
{
// do nothing else
}
//*****************************************************************************
//
// SYNOPSIS
//
option_stream& operator>>( option_stream &os, option_stream::option &o )
//
// DESCRIPTION
//
// Parse and extract an option from an option stream (argv values).
// Options begin with either a '-' for short options or a "--" for long
// options. Either a '-' or "--" by itself explicitly ends the options;
// however, the difference is that '-' is returned as the first non-option
// whereas "--" is skipped entirely.
//
// When there are no more options, the option_stream converts to bool as
// false. The option_stream's shift() member is the number of options
// parsed which the caller can use to adjust argc and argv.
//
// Short options can take an argument either as the remaining characters
// of the same argv or in the next argv unless the next argv looks like an
// option by beginning with a '-').
//
// Long option names can be abbreviated so long as the abbreviation is
// unambiguous. Long options can take an argument either directly after a
// '=' in the same argv or in the next argv (but without an '=') unless
// the next argv looks like an option by beginning with a '-').
//
// PARAMETERS
//
// os The option_stream to extract options from.
//
// o The option to deposit into.
//
// RETURN VALUE
//
// Returns the passed-in option_stream.
//
//*****************************************************************************
{
register char *arg;
register option_stream::spec const *s, *found = 0;
bool was_short_option = false;
o.short_name_ = '\0';
if ( os.next_c_ && *os.next_c_ ) {
//
// We left off within a grouped set of short options taking no
// arguments, i.e., instead of -a -b -c, the user did -abc and next_c_
// points to a character past 'a'.
//
arg = os.next_c_;
goto short_option;
}
if ( ++os.argi_ >= os.argc_ ) // no more arguments
goto the_end;
arg = os.argv_[ os.argi_ ];
if ( !arg || *arg != '-' || !*++arg ) // no more options
goto the_end;
if ( *arg == '-' ) {
if ( !*++arg ) { // "--": end of options
++os.argi_;
goto the_end;
}
was_short_option = false;
//
// Got the start of a long option: find the last character of its name.
//
char *end;
for ( end = arg; *end && *end != '='; ++end ) ;
//
// Now look through the options table for a match.
//
for ( s = os.specs_; s->long_name; ++s ) {
unsigned const len = end - arg;
if ( ::strncmp( arg, s->long_name, len ) )
continue;
if ( ::strlen( s->long_name ) == len ) {
found = s; // exact match
break;
}
if ( !found ) {
found = s; // partial match
continue;
}
ERROR << '"';
::copy( arg, end, ostream_iterator<char>(os.err_, "") );
os.err_ << "\" is ambiguous\n";
goto option_error;
}
if ( !found ) {
ERROR << '"';
::copy( arg, end, ostream_iterator<char>(os.err_, "") );
os.err_ << "\" unrecognized\n";
goto option_error;
}
//
// Got a long option: now see about its argument.
//
arg = 0;
switch ( found->arg_type ) {
case option_stream::os_arg_none:
if ( *end == '=' ) {
ERROR << '"' << found->long_name
<< "\" takes no argument\n";
goto option_error;
}
break;
case option_stream::os_arg_req:
case option_stream::os_arg_opt:
if ( *end == '=' ) {
arg = ++end;
break;
}
goto arg_next;
default:
goto bad_spec;
}
goto check_arg;
}
short_option:
was_short_option = true;
//
// Got a single '-' for a short option: look for it in the specs.
//
for ( s = os.specs_; s->short_name; ++s )
if ( *arg == s->short_name ) {
found = s;
break;
}
if ( !found ) {
ERROR << '"' << *arg << "\" unrecognized\n";
goto option_error;
}
//
// Found the short option: now see about its argument.
//
switch ( found->arg_type ) {
case option_stream::os_arg_none:
//
// Set next_c_ in case the user gave a grouped set of short options
// (see the comment near the beginning) so we can pick up where we
// left off on the next call.
//
os.next_c_ = arg + 1;
arg = 0;
break;
case option_stream::os_arg_req:
case option_stream::os_arg_opt:
//
// Reset next_c_ since an option with either a required or optional
// argument terminates a grouped set of options.
//
os.next_c_ = 0;
if ( !*++arg ) {
//
// The argument, if any, is given in the next argv.
//
arg_next: if ( ++os.argi_ >= os.argc_ )
break;
arg = os.argv_[ os.argi_ ];
if ( *arg == '-' ) {
//
// The next argv looks like an option so assume it is one
// and that there is no argument for this option.
//
arg = 0;
}
}
break;
default:
goto bad_spec;
}
check_arg:
if ( (arg && *arg) || found->arg_type != option_stream::os_arg_req ) {
o.short_name_ = found->short_name;
o.arg_ = arg;
return os;
}
ERROR << '"';
if ( was_short_option )
os.err_ << found->short_name;
else
os.err_ << found->long_name;
os.err_ << "\" requires an argument\n";
// fall through
option_error:
o.arg_ = '\0';
return os;
the_end:
os.end_ = true;
return os;
bad_spec:
ERROR << "invalid option argument spec: " << found->arg_type << '\n';
::abort();
}
} // namespace PJL
//*****************************************************************************
/*#define TEST_OPTION_STREAM /**/
#ifdef TEST_OPTION_STREAM
using namespace PJL;
int main( int argc, char *argv[] ) {
static option_stream::spec const spec[] = {
"n-no-arg", 0, 'n',
"m-no-arg", 0, 'm',
"r-req-arg", 1, 'r',
"o-opt-arg", 2, 'o',
0,
};
option_stream opt_in( argc, argv, spec );
option_stream::option opt;
while ( opt_in >> opt ) {
switch ( opt ) {
case 'm':
cout << "got --m-no-arg\n";
break;
case 'n':
cout << "got --n-no-arg\n";
break;
case 'r':
cout << "got --r-req-arg=" << opt.arg() << '\n';
break;
case 'o':
cout << "got --o-opt-arg=";
cout << (opt.arg() ? opt.arg() : "(null)") << '\n';
break;
default:
cout << "got weird=" << (int)(char)opt << '\n';
}
}
cout << "shift=" << opt_in.shift() << '\n';
argc -= opt_in.shift();
argv += opt_in.shift();
cout << "argc=" << argc << endl;
cout << "first non-option=" << (argv[0] ? argv[0] : "(null)") << endl;
}
#endif /* TEST_OPTION_STREAM */
/* vim:set et sw=4 ts=4: */
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