1 files changed, 122 insertions, 0 deletions
diff --git a/stack.h b/stack.h
new file mode 100644
index 0000000..c315729
--- /dev/null
+++ b/stack.h
@@ -0,0 +1,122 @@
+/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef STACK_H
+#define STACK_H
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include <SDL_stdinc.h>
+#include <cards.h>
+
+#ifndef STACK_CAP
+#define STACK_CAP 52
+#endif
+
+#if STACK_CAP < 52
+#error "Stack capacity too small for deck"
+#endif
+
+typedef Sint8 Card;
+
+static inline int suit(Card card) {
+	card = abs(card);
+	if (card > Cards_Spade) {
+		return Cards_Spade;
+	} else if (card > Cards_Heart) {
+		return Cards_Heart;
+	} else if (card > Cards_Diamond) {
+		return Cards_Diamond;
+	} else {
+		return Cards_Club;
+	}
+}
+
+static inline int color(Card card) {
+	return suit(card) == Cards_Diamond || suit(card) == Cards_Heart;
+}
+
+static inline int rank(Card card) {
+	return abs(card) - suit(card);
+}
+
+struct Stack {
+	Uint8 len;
+	Card cards[STACK_CAP];
+};
+
+static const struct Stack Deck = {
+	.len = 52,
+	.cards = {
+		-1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11, -12, -13,
+		-14, -15, -16, -17, -18, -19, -20, -21, -22, -23, -24, -25, -26,
+		-27, -28, -29, -30, -31, -32, -33, -34, -35, -36, -37, -38, -39,
+		-40, -41, -42, -43, -44, -45, -46, -47, -48, -49, -50, -51, -52,
+	},
+};
+
+static inline void clear(struct Stack *stack) {
+	stack->len = 0;
+}
+
+static inline void push(struct Stack *stack, Card card) {
+	assert(stack->len < STACK_CAP);
+	stack->cards[stack->len++] = card;
+}
+
+static inline Card pop(struct Stack *stack) {
+	if (!stack->len) return 0;
+	return stack->cards[--stack->len];
+}
+
+static inline Card peek(const struct Stack *stack) {
+	if (!stack->len) return 0;
+	return stack->cards[stack->len - 1];
+}
+
+static inline void flipTo(struct Stack *dst, struct Stack *src, Uint8 n) {
+	if (n > src->len) n = src->len;
+	for (Uint8 i = 0; i < n; ++i) {
+		push(dst, -pop(src));
+	}
+}
+
+static inline void moveTo(struct Stack *dst, struct Stack *src, Uint8 n) {
+	if (n > src->len) n = src->len;
+	for (Uint8 i = 0; i < n; ++i) {
+		push(dst, src->cards[src->len - n + i]);
+	}
+	src->len -= n;
+}
+
+static inline int randUniform(int bound) {
+	for (;;) {
+		int r = rand();
+		if (r >= RAND_MAX % bound) return r % bound;
+	}
+}
+
+static inline void shuffle(struct Stack *stack) {
+	for (Uint8 i = stack->len - 1; i > 0; --i) {
+		Uint8 j = randUniform(i + 1);
+		Card x = stack->cards[i];
+		stack->cards[i] = stack->cards[j];
+		stack->cards[j] = x;
+	}
+}
+
+#endif