Add a 'decoder' for streams already in our native format

src/codecs/CMakeLists.txt

@@ -4,7 +4,7 @@
 
 idf_component_register(
   SRCS "dr_flac.cpp" "codec.cpp" "mad.cpp" "opus.cpp" "vorbis.cpp"
-       "source_buffer.cpp" "sample.cpp" "wav.cpp"
+       "source_buffer.cpp" "sample.cpp" "wav.cpp" "native.cpp"
   INCLUDE_DIRS "include"
   REQUIRES "result" "libmad" "drflac" "tremor" "opusfile" "memory" "util"
        "komihash")

src/codecs/codec.cpp

@@ -11,6 +11,7 @@
 
 #include "dr_flac.hpp"
 #include "mad.hpp"
+#include "native.hpp"
 #include "opus.hpp"
 #include "types.hpp"
 #include "vorbis.hpp"
@@ -30,6 +31,8 @@ auto StreamTypeToString(StreamType t) -> std::string {
       return "Flac";
     case StreamType::kOpus:
       return "Opus";
+    case StreamType::kNative:
+      return "Native";
     default:
       return "";
   }
@@ -47,6 +50,8 @@ auto CreateCodecForType(StreamType type) -> std::optional<ICodec*> {
       return new XiphOpusDecoder();
     case StreamType::kWav:
       return new WavDecoder();
+    case StreamType::kNative:
+      return new NativeDecoder();
     default:
       return {};
   }

src/codecs/include/native.hpp

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <optional>
+#include <span>
+#include <string>
+#include <utility>
+
+#include "mad.h"
+#include "sample.hpp"
+#include "source_buffer.hpp"
+
+#include "codec.hpp"
+
+namespace codecs {
+
+class NativeDecoder : public ICodec {
+ public:
+  NativeDecoder();
+
+  auto OpenStream(std::shared_ptr<IStream> input, uint32_t offset)
+      -> cpp::result<OutputFormat, Error> override;
+
+  auto DecodeTo(std::span<sample::Sample> destination)
+      -> cpp::result<OutputInfo, Error> override;
+
+  NativeDecoder(const NativeDecoder&) = delete;
+  NativeDecoder& operator=(const NativeDecoder&) = delete;
+
+ private:
+  std::shared_ptr<IStream> input_;
+};
+
+}  // namespace codecs

src/codecs/include/types.hpp

@@ -16,6 +16,7 @@ enum class StreamType {
   kFlac,
   kOpus,
   kWav,
+  kNative,
 };
 
 auto StreamTypeToString(StreamType t) -> std::string;

src/codecs/native.cpp

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "native.hpp"
+
+#include <cstdint>
+#include <cstring>
+#include <optional>
+
+#include "esp_heap_caps.h"
+#include "mad.h"
+
+#include "codec.hpp"
+#include "esp_log.h"
+#include "result.hpp"
+#include "sample.hpp"
+#include "types.hpp"
+
+namespace codecs {
+
+NativeDecoder::NativeDecoder() : input_() {}
+
+auto NativeDecoder::OpenStream(std::shared_ptr<IStream> input, uint32_t offset)
+    -> cpp::result<OutputFormat, ICodec::Error> {
+  input_ = input;
+  return OutputFormat{
+      .num_channels = 1,
+      .sample_rate_hz = 48000,
+      .total_samples = {},
+  };
+}
+
+auto NativeDecoder::DecodeTo(std::span<sample::Sample> output)
+    -> cpp::result<OutputInfo, Error> {
+  size_t bytes = input_->Read({
+      reinterpret_cast<std::byte*>(output.data()),
+      output.size_bytes(),
+  });
+  return OutputInfo{
+      .samples_written = bytes / sizeof(sample::Sample),
+      .is_stream_finished = false,
+  };
+}
+
+}  // namespace codecs