Add initial support for reading an asset pack

include/pak.h

@@ -4,6 +4,11 @@
 #include "aliases.h"
 #include <stdbool.h>
 
+typedef struct {
+  u64 size;
+  u8 *data;
+} buf_t;
+
 typedef struct {
   u64 offset;
   u64 length;
@@ -32,6 +37,11 @@ typedef struct {
   toc_t toc;
 } pak_t;
 
+typedef struct pak_read pak_read_t;
+
 bool create_asset_pack(const char *dirpath, const char *output);
+pak_read_t *load_asset_pack(const char *filepath);
+// buf_t read_file_from_pack(pak_read_t *pack, const char *filename);
+void close_asset_pack(pak_read_t **pack);
 
 #endif // !PAK_H

src/pak.c

@@ -13,6 +13,14 @@
 #define PAK_PATCH 0
 #define PAK_EXT ".pak"
 
+struct pak_read {
+  pak_t header;
+  u8 *buf;
+  u8 *toc;
+  u64 assets_length;
+  u8 *assets;
+};
+
 toc_entry_t *create_toc_entry(const char *name, u64 offset);
 void write_toc_entry(toc_entry_t *entry, FILE *fp);
 void write_toc_entries(const toc_t *toc, toc_entry_t **entries, FILE *fp);
@@ -111,6 +119,64 @@ RETURN_CREATE_ASSET_PAK:
   return created;
 }
 
+pak_read_t *load_asset_pack(const char *filepath) {
+  char full_path[PATH_MAX] = {0};
+
+  realpath(filepath, full_path);
+
+  pak_read_t *pack = NULL;
+
+  FILE *fp = fopen(full_path, "rb");
+  if (!fp) {
+    goto RETURN_LOAD_ASSET_PACK;
+  }
+
+  pack = (pak_read_t *)malloc(sizeof(pak_read_t));
+  if (!pack) {
+    goto CLOSE_FILE_LOAD_ASSET_PACK;
+  }
+
+  u64 file_size = get_file_length(fp);
+
+  fread((void *)(&(pack->header)), sizeof(pak_t), 1, fp);
+
+  u64 data_size = file_size - sizeof(pak_t);
+
+  pack->buf = (u8 *)malloc(data_size);
+  if (!(pack->buf)) {
+    free(pack);
+
+    pack = NULL;
+
+    goto CLOSE_FILE_LOAD_ASSET_PACK;
+  }
+
+  fread((void *)(pack->buf), data_size, 1, fp);
+
+  pack->toc = pack->buf;
+
+  pack->assets_length = data_size - pack->header.toc.size;
+
+  pack->assets = pack->buf + pack->header.toc.size;
+
+CLOSE_FILE_LOAD_ASSET_PACK:
+  fclose(fp);
+
+RETURN_LOAD_ASSET_PACK:
+  return pack;
+}
+
+// buf_t read_file_from_pack(pak_read_t *pack, const char *filename) {}
+
+void close_asset_pack(pak_read_t **pack) {
+  if (!(*pack)) {
+    return;
+  }
+
+  free(*pack);
+  *pack = NULL;
+}
+
 toc_entry_t *create_toc_entry(const char *name, u64 offset) {
   u64 length = strlen(name);
   u64 size = sizeof(toc_entry_t) + length + 1;