Deck Implementation

Implemented a Deck type that has a new function that returns an
unshuffled deck. Also wrote an integration test for the new function to
make sure that it works.

src/card.rs

@@ -1,5 +1,6 @@
 use std::fmt;
 
+#[derive(Debug, Clone, Copy)]
 pub struct Card {
     pub suit: u8,
     pub value: u8,

src/deck.rs

@@ -0,0 +1,41 @@
+use super::card::Card;
+
+pub struct Deck {
+    deck_size: u64,
+    current_card: u64,
+    cards: Vec<Card>,
+}
+
+impl Deck {
+    pub fn new(num_decks: u64) -> Self {
+        let deck_size: u64 = num_decks * 52;
+        let mut cards: Vec<Card> = Vec::new();
+
+        for card in 0..deck_size {
+            let value = (card % 13) as u8;
+            let suit = ((card / 13) % 4) as u8;
+
+            cards.push(Card {
+                value: value,
+                suit: suit,
+            });
+        }
+
+        Deck {
+            deck_size: deck_size,
+            current_card: 0,
+            cards: cards,
+        }
+    }
+
+    pub fn get_next_card(&mut self) -> Card {
+        let next_card = self.cards[self.current_card as usize];
+        self.current_card += 1;
+
+        next_card
+    }
+
+    pub fn deck_size(&self) -> usize {
+        self.deck_size as usize
+    }
+}

src/lib.rs

@@ -2,6 +2,9 @@ use std::error::Error;
 
 mod card;
 mod deck;
+
+pub use deck::Deck;
+
 mod gamestate;
 mod hand;
 

tests/deck_tests.rs

@@ -0,0 +1,18 @@
+use blackjack::Deck;
+
+#[test]
+fn check_num_decks() {
+    let mut num_card: [u64; 52] = [0; 52];
+    let num_decks = 8;
+    let mut deck = Deck::new(num_decks as u64);
+
+    for _ in 0..deck.deck_size() {
+        let next_card = deck.get_next_card();
+        let card_pos = next_card.suit * 13 + next_card.value;
+        num_card[card_pos as usize] += 1;
+    }
+
+    for card in 0..num_card.len() {
+        assert_eq!(num_card[card], num_decks);
+    }
+}