4 files changed, 172 insertions, 0 deletions
diff --git a/src/resources/image.c b/src/resources/image.c
new file mode 100644
index 0000000..cd2c317
--- /dev/null
+++ b/src/resources/image.c
@@ -0,0 +1,48 @@
+#include <SDL.h>
+#include <SDL_image.h>
+#include "../logging.h"
+#include "image.h"
+#include "resource.h"
+
+struct resource_table img_res;
+
+struct image *
+img_png_get(const char *path)
+{
+	SDL_RWops *rwops;
+	struct image *img;
+
+	img = (struct image *) resource_get(&img_res, path);
+	if (img != NULL) {
+		resource_use((struct resource *) img);
+		return img;
+	}
+
+	img = resource_alloc(path, sizeof(*img));
+	rwops = SDL_RWFromFile(path, "rb");
+	img->image = IMG_LoadPNG_RW(rwops);
+	if (!img->image) {
+		err(1, "Failed to load image \"%s\" (%s)",
+				path, IMG_GetError());
+	}
+
+	resource_use((struct resource *) img);
+	resource_add(&img_res, path, (struct resource *) img);
+
+	return img;
+}
+
+void
+img_png_free(struct image *image)
+{
+	SDL_Surface *data;
+
+	if (image == NULL) {
+		return;
+	}
+
+	data = image->image;
+	if (resource_free(&img_res, (struct resource *) image)) {
+		SDL_FreeSurface(data);
+	}
+}
diff --git a/src/resources/image.h b/src/resources/image.h
new file mode 100644
index 0000000..92ef040
--- /dev/null
+++ b/src/resources/image.h
@@ -0,0 +1,14 @@
+#ifndef IMAGE_H
+#define IMAGE_H
+
+#include "resource.h"
+
+struct image {
+	struct resource res;
+	SDL_Surface *image;
+};
+
+struct image *img_png_get(const char *path);
+void img_png_free(struct image *image);
+
+#endif
diff --git a/src/resources/resource.c b/src/resources/resource.c
new file mode 100644
index 0000000..ebfcf27
--- /dev/null
+++ b/src/resources/resource.c
@@ -0,0 +1,87 @@
+#include <stdlib.h>
+#include <string.h>
+#include "resource.h"
+
+#include "../logging.h"
+
+inline void *
+resource_alloc(const char *path, size_t size)
+{
+	void *new_res;
+
+	debug("Allocating resource \"%s\"...", path);
+	new_res = malloc(size);
+	if (new_res == NULL) {
+		err(1, "Failed to allocate resource \"%s\"", path);
+		return NULL;
+	}
+	memset(new_res, 0, size);
+
+	return new_res;
+}
+
+struct resource *
+resource_get(struct resource_table *resources, const char *path)
+{
+	struct resource *res;
+
+	for (res = resources->head; res != NULL; res = res->next) {
+		if (strcmp(res->path, path) == 0) {
+			debug("Found resource \"%s\"", path);
+			return res;
+		}
+	}
+
+	return NULL;
+}
+
+void
+resource_add(struct resource_table *resources, const char *path,
+		struct resource *new_res)
+{
+	new_res->path = strdup(path);
+	new_res->prev = resources->tail;
+	new_res->next = NULL;
+
+	if (resources->head == NULL) {
+		resources->head = new_res;
+	} else {
+		resources->tail->next = new_res;
+	}
+	resources->tail = new_res;
+}
+
+/* XXX: Not thread-safe. */
+void
+resource_use(struct resource *resource)
+{
+	++resource->refs;
+}
+
+int
+resource_free(struct resource_table *resources, struct resource *resource)
+{
+	if (resource == NULL) {
+		return -1;
+	}
+
+	debug("Releasing resource with path \"%s\" and %d refs...",
+			resource->path, resource->refs);
+
+	if (--resource->refs == 0) {
+		debug("Freeing resource with path \"%s\"...", resource->path);
+		if (resource->prev == NULL) {
+			resources->head = resource->next;
+		} else {
+			resource->prev->next = resource->next;
+		}
+		if (resource->next == NULL) {
+			resources->tail = resource->prev;
+		} else {
+			resource->next->prev = resource->prev;
+		}
+		free(resource);
+		return 1;
+	}
+	return 0;
+}
diff --git a/src/resources/resource.h b/src/resources/resource.h
new file mode 100644
index 0000000..ada91fd
--- /dev/null
+++ b/src/resources/resource.h
@@ -0,0 +1,23 @@
+#ifndef RESOURCE_H
+#define RESOURCE_H
+
+struct resource_table {
+	struct resource *head;
+	struct resource *tail;
+};
+struct resource {
+	char *path;
+	int refs;
+	struct resource *prev;
+	struct resource *next;
+};
+
+extern inline void *resource_alloc(const char *path, size_t size);
+struct resource *resource_get(struct resource_table *resources,
+		const char *path);
+void resource_add(struct resource_table *resources, const char *path,
+		struct resource *new_res);
+void resource_use(struct resource *resource);
+int resource_free(struct resource_table *resources, struct resource *resource);
+
+#endif