This fixes a regression on real games due to the fact that
we have some mismatches:
history[st->gamePly - i] != stp->key
when st->gamePly - i == 0,this is due to a nasty bug I have
introduced when using std::vector<> as StateInfo backup. The
point is that StateInfo keeps inside a pointer to the previous
StateInfo in a kind of linked list. But when std::vector<> is
resized reallocates a larger chunk of memory and moves the
data there so these pointers became stale.
This patch fixes the issue.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
const string StartPositionFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
// Keep track of position keys along the setup moves (from start position to the
const string StartPositionFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
// Keep track of position keys along the setup moves (from start position to the
- // position just before to start searching). This is needed by draw detection.
- std::vector<StateInfo> SetupState(200, StateInfo());
+ // position just before to start searching). This is needed by draw detection
+ // where, due to 50 moves rule, we need to ckeck at most 100 plies back.
+ StateInfo StateRingBuf[102], *SetupState = StateRingBuf;
// UCIParser is a class for parsing UCI input. The class
// is actually a string stream built on a given input string.
// UCIParser is a class for parsing UCI input. The class
// is actually a string stream built on a given input string.
// Parse move list (if any)
while (up >> token && (m = move_from_uci(pos, token)) != MOVE_NONE)
{
// Parse move list (if any)
while (up >> token && (m = move_from_uci(pos, token)) != MOVE_NONE)
{
- SetupState.push_back(StateInfo());
- pos.do_move(m, SetupState.back());
+ pos.do_move(m, *SetupState);
+
+ // Increment pointer to StateRingBuf circular buffer
+ if (++SetupState - StateRingBuf >= 102)
+ SetupState = StateRingBuf;