Added Encoder And Test for Decoder and Data Converter

README.md

@@ -34,6 +34,7 @@ Provided structs:
   - [x] `DelayNode`
   - [x] custom nodes
 - [x] `Decoder` (missing methods)
+- [x] `Encoder` (missing methods)
 - [x] `DataConverter` 
 
 ## Getting started
@@ -50,7 +51,7 @@ pub fn build(b: *std.Build) void {
 }
 ```
 
-Now in your code you may import and use `zaudio`:
+Now in your code you may import and use the high level API of `zaudio`:
 
 ```zig
 const zaudio = @import("zaudio");
@@ -72,3 +73,60 @@ pub fn main() !void {
     ...
 }
 ```
+
+Or use the low level API which is similar to the original miniaudio library, but because the callback function is bridged from the original C library, you must explicitly handle the errors at the callback level:
+
+```zig
+const zaudio = @import("zaudio");
+
+pub fn main() !void {
+  ...
+  zaudio.init(std.heap.smp_allocator);
+  defer zaudio.deinit();
+
+  const decoder_config = zaudio.Decoder.Config.initDefault();
+  var mp3_decoder = try zaudio.Decoder.createFromFile("testing_media/Accipiter Supersaw Demo.mp3", decoder_config);
+  defer mp3_decoder.destroy();
+
+  // device
+  var device_config = zaudio.Device.Config.init(.playback);
+  device_config.playback.format = zaudio.Format.float32;
+  device_config.playback.channels = 2;
+  device_config.sample_rate = SAMPLE_RATE;
+  device_config.data_callback = data_callback; // we will fill that with actual signal source
+  device_config.user_data = mp3_decoder;
+
+  const device = zaudio.Device.create(null, device_config) catch {
+      @panic("Failed to open playback device");
+  };
+  defer device.destroy();
+
+  zaudio.Device.start(device) catch {
+      zaudio.Device.destroy(device);
+      @panic("Failed to start playback device");
+  };
+  ...
+}
+
+fn data_callback(device: *zaudio.Device, pOutput: ?*anyopaque, _: ?*const anyopaque, frame_count: u32) callconv(.c) void {
+    const decoder_opt: ?*zaudio.Decoder = @ptrCast(device.getUserData());
+
+    if (decoder_opt) |decoder| {
+        var frames_read: u64 = 0;
+
+        _ = try decoder.readPCMFrames(pOutput.?, frame_count) catch |err| {
+            std.debug.print("ERROR: {any}", .{err});
+            return;
+        };
+
+        if (frames_read < frame_count) {
+            decoder.seekToPCMFrames(0) catch {
+                @panic("cannot seek");
+            };
+        }
+    } else {
+        return;
+    }
+}
+
+```

build.zig

@@ -48,7 +48,6 @@ pub fn build(b: *std.Build) void {
         .file = b.path("libs/miniaudio/miniaudio.c"),
         .flags = &.{
             "-DMA_NO_WEBAUDIO",
-            "-DMA_NO_ENCODING",
             "-DMA_NO_NULL",
             "-DMA_NO_JACK",
             "-DMA_NO_DSOUND",

src/zaudio.c

@@ -808,4 +808,84 @@ void zaudioDecoderDestroy(
     s_mem.onFree(handle, s_mem.pUserData);
 }
 
+void* zaudioDecoderGetUserData(ma_decoder* handle) {
+    assert(handle != NULL);
+    return handle->pUserData;
+}
+
+//--------------------------------------------------------------------------------------------------
+void zaudioEncoderConfigInit(
+    ma_encoding_format encoding_format, 
+    ma_format format, 
+    ma_uint32 channels, 
+    ma_uint32 sample_rate,
+    ma_encoder_config* out_config
+){
+    assert(out_config != NULL);
+    *out_config = ma_encoder_config_init(encoding_format, format, channels, sample_rate);
+}
+
+
+ma_result zaudioEncoderCreate(
+    ma_encoder_write_proc on_write, 
+    ma_encoder_seek_proc on_seek, 
+    void* user_data, 
+    const ma_encoder_config* config, 
+    ma_encoder** out_handle
+){
+    assert(user_data != NULL && config != NULL && out_handle != NULL);
+    *out_handle = s_mem.onMalloc(sizeof(ma_encoder), s_mem.pUserData);
+    ma_result res = ma_encoder_init(on_write, on_seek, user_data, config, *out_handle);
+    if (res != MA_SUCCESS){
+        s_mem.onFree(*out_handle, s_mem.pUserData);
+        *out_handle = NULL;
+    }
+    return res;
+}
+
+ma_result zaudioEncoderCreateFromVfs(
+    ma_vfs* vfs, 
+    const char* file_path, 
+    const ma_encoder_config* config, 
+    ma_encoder** out_handle
+){
+    assert(vfs != NULL && file_path != NULL && config != NULL && out_handle != NULL);
+    *out_handle = s_mem.onMalloc(sizeof(ma_encoder), s_mem.pUserData);
+    ma_result res = ma_encoder_init_vfs(vfs, file_path, config, *out_handle);
+    if(res != MA_SUCCESS){
+        s_mem.onFree(*out_handle, s_mem.pUserData);
+        *out_handle = NULL;
+    }
+    return res;
+}
+
+ma_result zaudioEncoderCreateFromFile(
+    const char* file_path, 
+    const ma_encoder_config* config, 
+    ma_encoder** out_handle
+){
+    assert(file_path != NULL && config != NULL && out_handle != NULL);
+    *out_handle = s_mem.onMalloc(sizeof(ma_encoder), s_mem.pUserData);
+    ma_result res = ma_encoder_init_file(file_path, config, out_handle);
+    if (res != MA_SUCCESS){
+        s_mem.onFree(*out_handle, s_mem.pUserData);
+        *out_handle = NULL;
+    }
+    return res;
+}
+
+void zaudioEncoderDestroy(
+    ma_encoder* handle
+){
+    assert(handle != NULL);
+    ma_encoder_uninit(handle);
+    s_mem.onFree(handle, s_mem.pUserData);
+}
+
+void* zaudioEncoderGetUserData(ma_encoder* handle) {
+    assert(handle != NULL);
+    return handle->pUserData;
+}
+
 //--------------------------------------------------------------------------------------------------
+