83 lines
1.5 KiB
Go
83 lines
1.5 KiB
Go
package board
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import (
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"strconv"
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)
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// Bitboard is defined as
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type Bitboard uint64
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// NewBitboard returns an initialized Bitboard.
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func NewBitboard(m map[Square]bool) Bitboard {
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s := ""
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for sq := 0; sq < 64; sq++ {
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if m[Square(sq)] {
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s += "1"
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} else {
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s += "0"
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}
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}
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bb, err := strconv.ParseUint(s, 2, 64)
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if err != nil {
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panic(err)
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}
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return Bitboard(bb)
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}
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// Map returns a map[Square]bool representation of this Bitboard.
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func (bb Bitboard) Map() map[Square]bool {
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m := map[Square]bool{}
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for sq := 0; sq < 64; sq++ {
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if bb&Square(sq).Bitboard() > 0 {
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m[Square(sq)] = true
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}
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}
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return m
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}
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// Squares returns a []Square of all bits in this Bitboard.
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func (bb Bitboard) Squares() []Square {
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squares := []Square{}
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for sq := 0; sq < 64; sq++ {
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if bb&Square(sq).Bitboard() > 0 {
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squares = append(squares, Square(sq))
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}
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}
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return squares
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}
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// Occupied returns true if the given Square is occupied.
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func (bb Bitboard) Occupied(sq Square) bool {
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return (uint64(bb) >> uint64(63-sq) & 1) == 1
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}
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// Draw returns visual representation of the bitboard useful for debugging.
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func (bb Bitboard) Draw() string {
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s := "\n A B C D E F G H\n"
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for r := 7; r >= 0; r-- {
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s += Rank(r).String()
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s += " "
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for f := 0; f < 8; f++ {
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sq := NewSquare(File(f), Rank(r))
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if bb.Occupied(sq) {
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s += "1"
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} else {
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s += "0"
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}
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s += " "
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}
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s += "\n"
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}
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return s
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}
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// Flip toggles the bit at the given square.
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func (bb *Bitboard) Flip(sq Square) {
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if !sq.IsValid() {
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return
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}
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oldBB := *bb
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newBB := oldBB ^ sq.Bitboard()
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*bb = newBB
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}
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