1 files changed, 98 insertions, 0 deletions
diff --git a/include/cnn1986_cache.c b/include/cnn1986_cache.c
new file mode 100644
index 0000000..d9545ac
--- /dev/null
+++ b/include/cnn1986_cache.c
@@ -0,0 +1,98 @@
+#include "cnn1986_cache.h"
+
+#define DATA_STONE_SHIFT 6
+#define DATA_COUNT_SHIFT (DATA_STONE_SHIFT+2)
+#define COLOUR_MASK      0x3F // 0b00111111
+
+uint32_t cnn1986_num_cached, cnn1986_max_num_cached;
+node_t *head = NULL, *tail = NULL;
+
+void cnn1986_cache_free(void) {
+	node_t *c = head, *n;
+	while (c) {
+		n = c->next;
+		free(c);
+		c = n;
+	}
+	head = NULL;
+	tail = NULL;
+}
+
+int cnn1986_cache_seek(float *out_result) {
+	node_t *c = head;
+
+	if (c == NULL) return EXIT_FAILURE;
+
+	uint8_t comp_data[25], fail;
+	for (int k=0; k<25; k++) {
+		comp_data[k] = (colours[k] & COLOUR_MASK)
+			| (STONE_AT(k) << DATA_STONE_SHIFT)
+			| (COUNT_AT(k) << DATA_COUNT_SHIFT);
+	}
+
+	// We've checked c = head already, so uncoditionally test it
+	do {
+		// Compare
+		fail = 0;
+		if (c->black_count == black_count && c->white_count == white_count) {
+			for (int k=0; k<25; k++) {
+				if (comp_data[k] != c->data[k]) {
+					fail = 1;
+					break;
+				}
+			}
+		} else { fail = 1; }
+
+		// Either seek next or move to front and return
+		if (fail) {
+			c = c->next;
+		} else {
+			*out_result = c->result;
+
+			// Move to front
+			if (c != head) {
+				if (tail == c) tail=c->prev;
+				if (c->next) c->next->prev = c->prev;
+				c->prev->next = c->next;
+				c->prev = NULL;
+				c->next = head;
+				head->prev = c;
+				head = c;
+			}
+
+			return EXIT_SUCCESS;
+		}
+	} while (c);
+
+	// Failed to find it
+	return EXIT_FAILURE;
+}
+
+int cnn1986_cache_insert(float in_result) {
+	node_t *new = malloc(sizeof(node_t));
+	if (new == NULL) return EXIT_FAILURE;
+	// TODO: check errno
+	new->prev = NULL;
+	new->next = head;
+	if (head) head->prev = new;
+	head = new;
+	new->result = in_result;
+	new->white_count = white_count;
+	new->black_count = black_count;
+	for (int k=0; k<25; k++) {
+		new->data[k] = (colours[k] & COLOUR_MASK)
+			| (STONE_AT(k) << DATA_STONE_SHIFT)
+			| (COUNT_AT(k) << DATA_COUNT_SHIFT);
+	}
+	if (cnn1986_num_cached == 0) tail = new;
+	cnn1986_num_cached++;
+
+	if (cnn1986_num_cached > cnn1986_max_num_cached) {
+		tail = tail->prev;
+		free(tail->next);
+		tail->next = NULL;
+		cnn1986_num_cached--;
+	}
+
+	return EXIT_SUCCESS;
+}