1 files changed, 114 insertions, 0 deletions
diff --git a/platform/winrt/mupdfwinrt/Cache.cpp b/platform/winrt/mupdfwinrt/Cache.cpp
new file mode 100644
index 00000000..77e253f0
--- /dev/null
+++ b/platform/winrt/mupdfwinrt/Cache.cpp
@@ -0,0 +1,114 @@
+#include "pch.h"
+#include "Cache.h"
+
+Cache::Cache(void)
+{
+	this->size = 0;
+	this->head = NULL;
+	this->tail = NULL;
+}
+
+Cache::~Cache(void)
+{
+}
+
+void Cache::Empty(fz_context *mu_ctx)
+{
+	if (this != nullptr) {
+		cache_entry_t *curr_entry = this->head;
+
+		while (curr_entry != NULL)
+		{
+			cache_entry_t *old_entry = curr_entry;
+			curr_entry = old_entry->next;
+			fz_drop_display_list(mu_ctx, old_entry->dlist);
+			delete old_entry;
+		}
+		this->size = 0;
+		this->head = NULL;
+		this->tail = NULL;
+	}
+}
+
+void Cache::AddEntry(int value, fz_display_list *dlist, fz_context *mu_ctx)
+{
+	std::lock_guard<std::mutex> lock(cache_lock);
+
+	/* If full, then delete the tail */
+	if (size >= MAX_DISPLAY_CACHE_SIZE)
+	{
+		cache_entry_t *curr_entry = this->tail;
+		cache_entry_t *prev_entry = curr_entry->prev;
+
+		if (prev_entry != NULL)
+			prev_entry->next = NULL;
+		else
+			head = NULL;
+
+		tail = prev_entry;
+
+		/* Decrement the caches rc of this list */
+		fz_drop_display_list(mu_ctx, curr_entry->dlist);
+		delete curr_entry;
+		size--;
+	}
+
+	/* Make a new entry and stick at head */
+	cache_entry_t *new_entry = new cache_entry_t;
+
+	new_entry->dlist = dlist;
+	new_entry->index = value;
+	new_entry->prev = NULL;
+	if (head == NULL)
+	{
+		new_entry->next = NULL;
+		head = new_entry;
+		tail = new_entry;
+	}
+	else
+	{
+		new_entry->next = head;
+		head->prev = new_entry;
+		head = new_entry;
+	}
+	size++;
+	/* We are going to use this item now */
+	fz_keep_display_list(mu_ctx, new_entry->dlist);
+}
+
+fz_display_list* Cache::UseEntry(int value, fz_context *mu_ctx)
+{
+	std::lock_guard<std::mutex> lock(cache_lock);
+	cache_entry_t *curr_entry = this->head;
+
+	while (curr_entry != NULL)
+	{
+		if (curr_entry->index == value)
+			break;
+		curr_entry = curr_entry->next;
+	}
+	if (curr_entry != NULL)
+	{
+		fz_keep_display_list(mu_ctx, curr_entry->dlist);
+		/* Move this to the front */
+		if (curr_entry != head)
+		{
+			cache_entry_t *prev_entry = curr_entry->prev;
+			cache_entry_t *next_entry = curr_entry->next;
+			prev_entry->next = next_entry;
+
+			if (next_entry != NULL)
+				next_entry->prev = prev_entry;
+			else
+				tail = prev_entry;
+
+			curr_entry->prev = NULL;
+			curr_entry->next = head;
+			head->prev = curr_entry;
+			head = curr_entry;
+		}
+		return curr_entry->dlist;
+	}
+	else
+		return NULL;
+}