WIP

asset_manager.odin

@@ -0,0 +1,185 @@
+//+build android
+package android
+
+import "core:c"
+
+foreign import android "system:android"
+
+/** Available access modes for opening assets with {@link AAssetManager_open} */
+AssetOpenMode :: enum c.int {
+    /** No specific information about how data will be accessed. **/
+    UNKNOWN      = 0,
+    /** Read chunks, and seek forward and backward. */
+    RANDOM       = 1,
+    /** Read sequentially, with an occasional forward seek. */
+    STREAMING    = 2,
+    /** Caller plans to ask for a read-only buffer with all data. */
+    BUFFER       = 3
+}
+
+// Same as sys/linux but this is i32 instead of i16
+Seek_Whence :: enum i32 {
+	SET  = 0,
+	CUR  = 1,
+	END  = 2,
+	DATA = 3,
+	HOLE = 4,
+}
+
+/**
+ * {@link AAssetManager} provides access to an application's raw assets by
+ * creating {@link AAsset} objects.
+ *
+ * AAssetManager is a wrapper to the low-level native implementation
+ * of the java {@link AAssetManager}, a pointer can be obtained using
+ * AAssetManager_fromJava().
+ *
+ * The asset hierarchy may be examined like a filesystem, using
+ * {@link AAssetDir} objects to peruse a single directory.
+ *
+ * A native {@link AAssetManager} pointer may be shared across multiple threads.
+ */
+AAssetManager :: struct{}
+
+/**
+ * {@link AAssetDir} provides access to a chunk of the asset hierarchy as if
+ * it were a single directory. The contents are populated by the
+ * {@link AAssetManager}.
+ *
+ * The list of files will be sorted in ascending order by ASCII value.
+ */
+ AAssetDir :: struct{}
+
+/**
+ * {@link AAsset} provides access to a read-only asset.
+ *
+ * {@link AAsset} objects are NOT thread-safe, and should not be shared across
+ * threads.
+ */
+AAsset :: struct{}
+
+foreign android {
+	/**
+	 * Open an asset.
+	 *
+	 * The object returned here should be freed by calling AAsset_close().
+	 */
+	AAssetManager_open :: proc(mgr: ^AAssetManager, filename: cstring, mode: AssetOpenMode) -> ^AAsset ---
+
+	/**
+	* Iterate over the files in an asset directory.  A NULL string is returned
+	* when all the file names have been returned.
+	*
+	* The returned file name is suitable for passing to AAssetManager_open().
+	*
+	* The string returned here is owned by the AssetDir implementation and is not
+	* guaranteed to remain valid if any other calls are made on this AAssetDir
+	* instance.
+	*/
+	AAssetDir_getNextFileName :: proc(assetDir: ^AAssetDir) -> cstring ---
+
+	/**
+	* Reset the iteration state of AAssetDir_getNextFileName() to the beginning.
+	*/
+	AAssetDir_rewind :: proc(assetDir: ^AAssetDir) ---
+
+	/**
+	* Close an opened AAssetDir, freeing any related resources.
+	*/
+	AAssetDir_close :: proc(assetDir: ^AAssetDir) ---
+
+	/**
+	* Attempt to read 'count' bytes of data from the current offset.
+	*
+	* Returns the number of bytes read, zero on EOF, or < 0 on error.
+	*/
+	AAsset_read :: proc(asset: ^AAsset, buf: rawptr, count: uint) -> i32 ---
+
+	/**
+	* Seek to the specified offset within the asset data.  'whence' uses the
+	* same constants as lseek()/fseek().
+	*
+	* Returns the new position on success, or (off_t) -1 on error.
+	*/
+	// TODO: should we just not bind these functions since their 64-bit counterparts are available?
+	// Because according to https://android.googlesource.com/platform/bionic/+/main/docs/32-bit-abi.md
+	// and the __RENAME_IF_FILE_OFFSET64() macro these functions are replaced with the 64-bit versions at
+	// runtime anyway (at least for 32-bit Android).
+	// off_t is replaced with off64_t too.
+	// I think all Android API version <21 should explicitly be unsupported both by Odin and the bindings here since
+	// this opens a can of worms that I do not like.
+	AAsset_seek :: proc(asset: ^AAsset, offset: off_t, whence: Seek_Whence) -> off_t ---
+
+	/**
+	* Seek to the specified offset within the asset data.  'whence' uses the
+	* same constants as lseek()/fseek().
+	*
+	* Uses 64-bit data type for large files as opposed to the 32-bit type used
+	* by AAsset_seek.
+	*
+	* Returns the new position on success, or (off64_t) -1 on error.
+	*/
+	AAsset_seek64 :: proc(asset: ^AAsset, offset: off64_t, whence: Seek_Whence) -> off64_t ---
+
+	/**
+	* Close the asset, freeing all associated resources.
+	*/
+	AAsset_close :: proc(asset: ^AAsset) ---
+
+	/**
+	* Get a pointer to a buffer holding the entire contents of the assset.
+	*
+	* Returns NULL on failure.
+	*/
+	AAsset_getBuffer :: proc(asset: ^AAsset) -> rawptr ---
+
+	/**
+	* Report the total size of the asset data.
+	*/
+	AAsset_getLength :: proc(asset: ^AAsset) -> off_t ---
+
+	/**
+	* Report the total size of the asset data. Reports the size using a 64-bit
+	* number insted of 32-bit as AAsset_getLength.
+	*/
+	AAsset_getLength64 :: proc(asset: ^AAsset) -> off64_t ---
+
+	/**
+	* Report the total amount of asset data that can be read from the current position.
+	*/
+	AAsset_getRemainingLength :: proc(asset: ^AAsset) -> off_t ---
+
+	/**
+	* Report the total amount of asset data that can be read from the current position.
+	*
+	* Uses a 64-bit number instead of a 32-bit number as AAsset_getRemainingLength does.
+	*/
+	AAsset_getRemainingLength64 :: proc(asset: ^AAsset) -> off64_t ---
+
+	/**
+	* Open a new file descriptor that can be used to read the asset data. If the
+	* start or length cannot be represented by a 32-bit number, it will be
+	* truncated. If the file is large, use AAsset_openFileDescriptor64 instead.
+	*
+	* Returns < 0 if direct fd access is not possible (for example, if the asset is
+	* compressed).
+	*/
+	AAsset_openFileDescriptor :: proc(asset: ^AAsset, outStart: ^off_t, outLength: ^off_t) -> i32 ---
+
+	/**
+	* Open a new file descriptor that can be used to read the asset data.
+	*
+	* Uses a 64-bit number for the offset and length instead of 32-bit instead of
+	* as AAsset_openFileDescriptor does.
+	*
+	* Returns < 0 if direct fd access is not possible (for example, if the asset is
+	* compressed).
+	*/
+	AAsset_openFileDescriptor64 :: proc(asset: ^AAsset, outStart: ^off64_t, outLength: ^off64_t) -> i32 ---
+
+	/**
+	* Returns whether this asset's internal buffer is allocated in ordinary RAM (i.e. not
+	* mmapped).
+	*/
+	AAsset_isAllocated :: proc(asset: ^AAsset) -> i32 ---
+}