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Code Issues Releases Wiki Activity

Rearrange bitbases C++11 way

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No functional change.
This commit is contained in:
Marco Costalba 2015-01-22 11:05:31 +01:00
parent 6390a3da94
commit 18375e3bfb
1 changed files with 16 additions and 18 deletions
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34
src/bitbase.cpp
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@ -17,7 +17,9 @@
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <algorithm>
#include <cassert>
#include <numeric>
#include <vector>
#include "bitboard.h"
@ -54,15 +56,15 @@ namespace {
inline Result& operator|=(Result& r, Result v) { return r = Result(r | v); }
struct KPKPosition {
KPKPosition() = default;
KPKPosition(unsigned idx);
operator Result() const { return result; }
Result classify(const std::vector<KPKPosition>& db)
{ return us == WHITE ? classify<WHITE>(db) : classify<BLACK>(db); }
private:
template<Color Us> Result classify(const std::vector<KPKPosition>& db);
unsigned id;
Color us;
Square bksq, wksq, psq;
Result result;
@ -82,24 +84,20 @@ bool Bitbases::probe(Square wksq, Square wpsq, Square bksq, Color us) {
void Bitbases::init() {
unsigned idx, repeat = 1;
std::vector<KPKPosition> db;
db.reserve(MAX_INDEX);
std::vector<KPKPosition> db(MAX_INDEX);
// Initialize db with known win / draw positions
for (idx = 0; idx < MAX_INDEX; ++idx)
db.push_back(KPKPosition(idx));
std::generate(db.begin(), db.end(), [](){ static unsigned id; return KPKPosition(id++); });
// Iterate through the positions until none of the unknown positions can be
// changed to either wins or draws (15 cycles needed).
while (repeat)
for (repeat = idx = 0; idx < MAX_INDEX; ++idx)
repeat |= (db[idx] == UNKNOWN && db[idx].classify(db) != UNKNOWN);
while (std::accumulate(db.begin(), db.end(), false, [&](bool repeat, KPKPosition& pos)
{ return (pos == UNKNOWN && pos.classify(db) != UNKNOWN) || repeat; }));
// Map 32 results into one KPKBitbase[] entry
for (idx = 0; idx < MAX_INDEX; ++idx)
if (db[idx] == WIN)
KPKBitbase[idx / 32] |= 1 << (idx & 0x1F);
for (auto& pos : db)
if (pos == WIN)
KPKBitbase[pos.id / 32] |= 1 << (pos.id & 0x1F);
}
@ -107,6 +105,7 @@ namespace {
KPKPosition::KPKPosition(unsigned idx) {
id = idx;
wksq = Square((idx >> 0) & 0x3F);
bksq = Square((idx >> 6) & 0x3F);
us = Color ((idx >> 12) & 0x01);
@ -148,7 +147,9 @@ namespace {
// as WIN, the position is classified as WIN, otherwise the current position is
// classified as UNKNOWN.
const Color Them = (Us == WHITE ? BLACK : WHITE);
const Color Them = (Us == WHITE ? BLACK : WHITE);
const Result Good = (Us == WHITE ? WIN : DRAW);
const Result Bad = (Us == WHITE ? DRAW : WIN);
Result r = INVALID;
Bitboard b = StepAttacksBB[KING][Us == WHITE ? wksq : bksq];
@ -166,10 +167,7 @@ namespace {
r |= db[index(BLACK, bksq, wksq, s + DELTA_N)]; // Double push
}
if (Us == WHITE)
return result = r & WIN ? WIN : r & UNKNOWN ? UNKNOWN : DRAW;
else
return result = r & DRAW ? DRAW : r & UNKNOWN ? UNKNOWN : WIN;
return result = r & Good ? Good : r & UNKNOWN ? UNKNOWN : Bad;
}
} // namespace