mpd/src/command/PositionArg.cxx

104 lines
2.9 KiB
C++

/*
* Copyright 2003-2021 The Music Player Daemon Project
* http://www.musicpd.org
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "PositionArg.hxx"
#include "protocol/Ack.hxx"
#include "protocol/ArgParser.hxx"
#include "protocol/RangeArg.hxx"
#include "queue/Playlist.hxx"
static unsigned
RequireCurrentPosition(const playlist &p)
{
int position = p.GetCurrentPosition();
if (position < 0)
throw ProtocolError(ACK_ERROR_PLAYER_SYNC,
"No current song");
return position;
}
unsigned
ParseInsertPosition(const char *s, const playlist &playlist)
{
const auto queue_length = playlist.queue.GetLength();
if (*s == '+') {
/* after the current song */
const unsigned current = RequireCurrentPosition(playlist);
assert(current < queue_length);
return current + 1 +
ParseCommandArgUnsigned(s + 1,
queue_length - current - 1);
} else if (*s == '-') {
/* before the current song */
const unsigned current = RequireCurrentPosition(playlist);
assert(current < queue_length);
return current - ParseCommandArgUnsigned(s + 1, current);
} else
/* absolute position */
return ParseCommandArgUnsigned(s, queue_length);
}
unsigned
ParseMoveDestination(const char *s, const RangeArg range, const playlist &p)
{
assert(!range.IsEmpty());
assert(!range.IsOpenEnded());
const unsigned queue_length = p.queue.GetLength();
if (*s == '+') {
/* after the current song */
unsigned current = RequireCurrentPosition(p);
assert(current < queue_length);
if (range.Contains(current))
throw ProtocolError(ACK_ERROR_ARG, "Cannot move current song relative to itself");
if (current >= range.end)
current -= range.Count();
return current + 1 +
ParseCommandArgUnsigned(s + 1,
queue_length - current - range.Count());
} else if (*s == '-') {
/* before the current song */
unsigned current = RequireCurrentPosition(p);
assert(current < queue_length);
if (range.Contains(current))
throw ProtocolError(ACK_ERROR_ARG, "Cannot move current song relative to itself");
if (current >= range.end)
current -= range.Count();
return current -
ParseCommandArgUnsigned(s + 1,
queue_length - current - range.Count());
} else
/* absolute position */
return ParseCommandArgUnsigned(s,
queue_length - range.Count());
}