From 5e494bac1bec3072602a7cd4d6f6cba1b5fbc32c Mon Sep 17 00:00:00 2001
From: Sara <sara@saragerretsen.nl>
Date: Sun, 24 Sep 2023 23:39:39 +0200
Subject: [PATCH] added asset manager

---
 src/assets.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/assets.h |  28 +++++++++++++++
 2 files changed, 128 insertions(+)
 create mode 100644 src/assets.c
 create mode 100644 src/assets.h

diff --git a/src/assets.c b/src/assets.c
new file mode 100644
index 0000000..1663acb
--- /dev/null
+++ b/src/assets.c
@@ -0,0 +1,100 @@
+#include "assets.h"
+#include <stdlib.h>
+#include <memory.h>
+
+typedef
+struct AssetData {
+    void* asset;
+    asset_id id;
+    AssetDestructor destructor;
+} AssetData;
+
+static AssetData* _assets = NULL;
+static size_t _assets_len = 0;
+static size_t _assets_cap = 0;
+static asset_id _next_id = 0;
+
+static
+void _resize_if_needed(size_t requested_len) {
+    if(requested_len < _assets_cap) {
+        return; // not needed.
+    }
+
+    size_t new_cap = _assets_cap ? _assets_cap : 8;
+    while(new_cap < requested_len) {
+        new_cap *= 2;
+    }
+    AssetData* new_assets = realloc(_assets, new_cap * sizeof(AssetData));
+    if(new_assets != NULL) {
+        _assets = new_assets;
+        _assets_cap = new_cap;
+    }
+}
+
+void assets_init() {
+    _assets = malloc(_assets_cap * sizeof(AssetData));
+    _next_id = 1;
+}
+
+asset_id store_asset(void* asset, AssetDestructor destructor) {
+    _resize_if_needed(_assets_len + 1);
+    AssetData* data = _assets + _assets_len;
+
+    data->asset = asset;
+    data->destructor = destructor;
+    data->id = _next_id;
+
+    ++_next_id;
+    ++_assets_len;
+
+    return data->id;
+}
+
+static
+AssetData* _internal_get_by_id(asset_id id) {
+    if(id == 0) {
+        return NULL;
+    }
+
+    for(size_t i = 0; i < _assets_len; ++i) {
+        if(_assets[i].id == id) {
+            return _assets + i;
+        }
+    }
+
+    return NULL;
+}
+
+void* get_asset(asset_id id) {
+    AssetData* found = _internal_get_by_id(id);
+    if(found != NULL) {
+        return found->asset;
+    }
+
+    return NULL;
+}
+
+asset_id get_asset_id(void* asset) {
+    for(size_t i = 0; i < _assets_len; ++i) {
+        if(_assets[i].asset == asset) {
+           return _assets[i].id; 
+        }
+    }
+
+    return 0;
+}
+
+void free_asset(asset_id id) {
+    AssetData* found = _internal_get_by_id(id);
+
+    if(found == NULL) {
+        return;
+    }
+
+    found->destructor(found->asset);
+
+    AssetData* next = found + 1;
+    size_t dif = next - (_assets + _assets_len);
+    memmove(found, next, dif);
+}
+
diff --git a/src/assets.h b/src/assets.h
new file mode 100644
index 0000000..3d3708f
--- /dev/null
+++ b/src/assets.h
@@ -0,0 +1,28 @@
+#ifndef _fencer_assets_h
+#define _fencer_assets_h
+
+#include <stdint.h>
+
+typedef void(*AssetDestructor)(void*);
+
+typedef uintptr_t asset_id;
+
+// Prepare asset management.
+// Other asset management functions are invalid until assets_init is called.
+void assets_init();
+// Clean up and shut down assets management.
+void assets_clean();
+// Clear all assets and reset to initial state.
+void assets_reset();
+// Submit an object to be managed as an asset. If the destructor is NULL, free will be used.
+// Returns zero if asset could not be stored.
+asset_id store_asset(void* asset, AssetDestructor destructor);
+// Get an asset already submitted to the asset manager.
+// Returns 0 if asset does not exist.
+void* get_asset(asset_id id);
+// Get an asset id, returns 0 if no such asset exists.
+asset_id get_asset_id(void* asset);
+// Free an asset managed by the asset manager using it's destructor, or free(..) if NULL.
+void free_asset(asset_id id);
+
+#endif // !_fencer_assets_h