1 files changed, 75 insertions, 91 deletions

diff --git a/src/codecs/mad.cpp b/src/codecs/mad.cpp
index c918e849..4afc9a77 100644
--- a/src/codecs/mad.cpp
+++ b/src/codecs/mad.cpp
@@ -1,8 +1,11 @@
 #include "mad.hpp"
+
 #include <cstdint>
 
 #include "mad.h"
 
+#include "codec.hpp"
+
 namespace codecs {
 
 static int32_t scaleTo24Bits(mad_fixed_t sample) {
@@ -32,118 +35,99 @@ MadMp3Decoder::~MadMp3Decoder() {
   mad_header_finish(&header_);
 }
 
-auto MadMp3Decoder::CanHandleExtension(std::string extension) -> bool {
-  return extension == "mp3";
+auto MadMp3Decoder::CanHandleFile(const std::string& path) -> bool {
+  return true;  // TODO.
 }
 
-auto GetOutputFormat() -> OutputFormat {
+auto MadMp3Decoder::GetOutputFormat() -> OutputFormat {
   return OutputFormat{
-      .num_channels = synth_.pcm.channels,
+      .num_channels = static_cast<uint8_t>(synth_.pcm.channels),
       .bits_per_sample = 24,
       .sample_rate_hz = synth_.pcm.samplerate,
   };
 }
 
-auto MadMp3Decoder::Process(uint8_t* input,
-                            std::size_t input_len,
-                            uint8_t* output,
-                            std::size_t output_length)
-    -> cpp::result<Result, Error> {
-  Result res {
-    .need_more_input = false, .input_processed = 0, .flush_output = false,
-    .output_written = 0,
-  }
-  while (true) {
-    // Only process more of the input if we're done sending off the
-    // samples for the previous frame.
-    if (current_sample_ == -1) {
-      ProcessInput(&res, input, input_len);
-    }
+auto MadMp3Decoder::ResetForNewStream() -> void {
+  has_decoded_header_ = false;
+}
 
-    // Write PCM samples to the output buffer. This always needs to be
-    // done, even if we ran out of input, so that we don't keep the last
-    // few samples buffered if the input stream has actually finished.
-    WriteOutputSamples(&res, output, output_length);
+auto MadMp3Decoder::SetInput(uint8_t* buffer, std::size_t length) -> void {
+  mad_stream_buffer(&stream_, buffer, length);
+}
 
-    if (res.need_more_input || res.flush_output) {
-      return res;
-    }
-  }
+auto MadMp3Decoder::GetInputPosition() -> std::size_t {
+  return stream_.next_frame - stream_.buffer;
+}
 
-  auto MadMp3Decoder::ProcessInput(Result * res, uint8_t * input,
-                                   std::size_t input_len)
-      ->void {
-    if (input != stream_.buffer) {
-      mad_stream_buffer(&stream_, input, input_len);
-    }
+auto MadMp3Decoder::ProcessNextFrame() -> cpp::result<bool, ProcessingError> {
+  if (!has_decoded_header_) {
+    // The header of any given frame should be representative of the
+    // entire stream, so only need to read it once.
+    mad_header_decode(&header_, &stream_);
+    has_decoded_header_ = true;
 
-    if (!has_decoded_header_) {
-      // The header of any given frame should be representative of the
-      // entire stream, so only need to read it once.
-      mad_header_decode(&header_, &stream);
-      has_decoded_header_ = true;
+    // TODO: Use the info in the header for something. I think the
+    // duration will help with seeking?
+  }
 
-      // TODO: Use the info in the header for something. I think the
-      // duration will help with seeking?
+  // Whatever was last synthesized is now invalid, so ensure we don't try to
+  // send it.
+  current_sample_ = -1;
+
+  // Decode the next frame. To signal errors, this returns -1 and
+  // stashes an error code in the stream structure.
+  if (mad_frame_decode(&frame_, &stream_) < 0) {
+    if (MAD_RECOVERABLE(stream_.error)) {
+      // Recoverable errors are usually malformed parts of the stream.
+      // We can recover from them by just retrying the decode.
+      return false;
     }
 
-    // Decode the next frame. To signal errors, this returns -1 and
-    // stashes an error code in the stream structure.
-    if (mad_frame_decode(&frame_, &stream_) < 0) {
-      if (MAD_RECOVERABLE(stream_.error)) {
-        // Recoverable errors are usually malformed parts of the stream.
-        // We can recover from them by just retrying the decode.
-        continue;
-      }
-
-      if (stream_.error = MAD_ERROR_BUFLEN) {
-        // The decoder ran out of bytes before it completed a frame. We
-        // need to return back to the caller to give us more data. Note
-        // that there might still be some unused data in the input, so we
-        // should calculate that amount and return it.
-        size_t remaining_bytes = stream.bufend - stream_.next_frame;
-        return remaining_bytes;
-      }
-
-      // The error is unrecoverable. Give up.
-      return cpp::fail(MALFORMED_DATA);
+    if (stream_.error == MAD_ERROR_BUFLEN) {
+      // The decoder ran out of bytes before it completed a frame. We
+      // need to return back to the caller to give us more data.
+      return true;
     }
 
-    // We've successfully decoded a frame!
-    // Now we need to synthesize PCM samples based on the frame, and send
-    // them downstream.
-    mad_synth_frame(&synth_, &frame_);
-    up_to_sample = 0;
+    // The error is unrecoverable. Give up.
+    return cpp::fail(MALFORMED_DATA);
   }
 
-  auto MadMp3Decoder::WriteOutputSamples(Result * res, uint8_t * output,
-                                         std::size_t output_length)
-      ->void {
-    size_t output_byte = 0;
-    // First ensure that we actually have some samples to send off.
-    if (current_sample_ < 0) {
-      return;
-    }
-    res->flush_output = true;
-
-    while (current_sample_ < synth_.pcm.length) {
-      if (output_byte + (3 * synth_.pcm.channels) >= output_length) {
-        res->output_written = output_byte;
-        return;
-      }
-
-      for (int channel = 0; channel < synth_.pcm.channels; channel++) {
-        uint32_t sample_24 = scaleTo24Bits(synth_.pcm.samples[channel][sample]);
-        output[output_byte++] = (sample_24 >> 0) & 0xff;
-        output[output_byte++] = (sample_24 >> 8) & 0xff;
-        output[output_byte++] = (sample_24 >> 16) & 0xff;
-      }
-      current_sample_++;
+  // We've successfully decoded a frame!
+  // Now we need to synthesize PCM samples based on the frame, and send
+  // them downstream.
+  mad_synth_frame(&synth_, &frame_);
+  current_sample_ = 0;
+  return false;
+}
+
+auto MadMp3Decoder::WriteOutputSamples(uint8_t* output,
+                                       std::size_t output_length)
+    -> std::pair<std::size_t, bool> {
+  size_t output_byte = 0;
+  // First ensure that we actually have some samples to send off.
+  if (current_sample_ < 0) {
+    return std::make_pair(output_byte, true);
+  }
+
+  while (current_sample_ < synth_.pcm.length) {
+    if (output_byte + (3 * synth_.pcm.channels) >= output_length) {
+      return std::make_pair(output_byte, false);
     }
 
-    // We wrote everything! Reset, ready for the next frame.
-    current_sample_ = -1;
-    res->output_written = output_byte;
+    for (int channel = 0; channel < synth_.pcm.channels; channel++) {
+      uint32_t sample_24 =
+          scaleTo24Bits(synth_.pcm.samples[channel][current_sample_]);
+      output[output_byte++] = (sample_24 >> 0) & 0xff;
+      output[output_byte++] = (sample_24 >> 8) & 0xff;
+      output[output_byte++] = (sample_24 >> 16) & 0xff;
+    }
+    current_sample_++;
   }
 
+  // We wrote everything! Reset, ready for the next frame.
+  current_sample_ = -1;
+  return std::make_pair(output_byte, true);
+}
+
 }  // namespace codecs