Playing card library
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943 B

package joker
import (
"math/rand"
"time"
)
// Deck defines a playing card deck containing any number of cards.
type Deck struct {
Cards Cards
rand *rand.Rand
}
// NewDeck initializes a deck of cards. A seed value of 0 is replaced with the
// current unix time in nanoseconds.
func NewDeck(c Cards, seed int64) *Deck {
if seed == 0 {
seed = time.Now().UnixNano()
}
return &Deck{Cards: c.Copy(), rand: rand.New(rand.NewSource(seed))}
}
// Shuffle randomizes the order of the deck using the Fisher-Yates shuffle
// algorithm.
func (d *Deck) Shuffle() {
for i := len(d.Cards) - 1; i > 0; i-- {
j := d.rand.Intn(i + 1)
d.Cards[i], d.Cards[j] = d.Cards[j], d.Cards[i]
}
}
// Draw removes cards from the deck and returns them as a slice.
func (d *Deck) Draw(count int) (cards Cards, ok bool) {
if count > len(d.Cards) {
return nil, false
}
cards = d.Cards[0:count].Copy()
d.Cards = d.Cards[count:]
return cards, true
}