1 files changed, 176 insertions, 0 deletions
diff --git a/src/codecs/miniflac.cpp b/src/codecs/miniflac.cpp
new file mode 100644
index 00000000..cc261f75
--- /dev/null
+++ b/src/codecs/miniflac.cpp
@@ -0,0 +1,176 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "miniflac.hpp"
+#include <stdint.h>
+#include <sys/_stdint.h>
+
+#include <cstdlib>
+
+#include "esp_heap_caps.h"
+#include "esp_log.h"
+#include "miniflac.h"
+#include "result.hpp"
+#include "sample.hpp"
+
+namespace codecs {
+
+[[maybe_unused]] static const char kTag[] = "flac";
+
+static constexpr size_t kMaxFrameSize = 4608;
+
+MiniFlacDecoder::MiniFlacDecoder()
+    : input_(),
+      buffer_(),
+      flac_(reinterpret_cast<miniflac_t*>(
+          heap_caps_malloc(sizeof(miniflac_t),
+                           MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT))),
+      current_sample_() {
+  miniflac_init(flac_.get(), MINIFLAC_CONTAINER_UNKNOWN);
+  for (int i = 0; i < samples_by_channel_.size(); i++) {
+    // Full decoded frames too big to fit in internal ram :(
+    samples_by_channel_[i] = reinterpret_cast<int32_t*>(
+        heap_caps_malloc(kMaxFrameSize * sizeof(int32_t), MALLOC_CAP_SPIRAM));
+  }
+}
+
+MiniFlacDecoder::~MiniFlacDecoder() {
+  for (int i = 0; i < samples_by_channel_.size(); i++) {
+    heap_caps_free(samples_by_channel_[i]);
+  }
+}
+
+auto MiniFlacDecoder::OpenStream(std::shared_ptr<IStream> input)
+    -> cpp::result<OutputFormat, Error> {
+  input_ = input;
+
+  MINIFLAC_RESULT res;
+  auto read_until_result = [&](auto fn) {
+    while (true) {
+      bool eof = buffer_.Refill(input_.get());
+      buffer_.ConsumeBytes(fn);
+      if (res == MINIFLAC_CONTINUE && !eof) {
+        continue;
+      }
+      break;
+    }
+  };
+
+  uint32_t sample_rate = 0;
+
+  read_until_result([&](cpp::span<std::byte> buf) -> size_t {
+    uint32_t bytes_used = 0;
+    res = miniflac_streaminfo_sample_rate(
+        flac_.get(), reinterpret_cast<const uint8_t*>(buf.data()),
+        buf.size_bytes(), &bytes_used, &sample_rate);
+    return bytes_used;
+  });
+
+  if (res != MINIFLAC_OK) {
+    return cpp::fail(Error::kMalformedData);
+  }
+
+  uint8_t channels = 0;
+
+  read_until_result([&](cpp::span<std::byte> buf) -> size_t {
+    uint32_t bytes_used = 0;
+    res = miniflac_streaminfo_channels(
+        flac_.get(), reinterpret_cast<const uint8_t*>(buf.data()),
+        buf.size_bytes(), &bytes_used, &channels);
+    return bytes_used;
+  });
+
+  if (res != MINIFLAC_OK) {
+    return cpp::fail(Error::kMalformedData);
+  }
+
+  uint64_t total_samples = 0;
+
+  read_until_result([&](cpp::span<std::byte> buf) -> size_t {
+    uint32_t bytes_used = 0;
+    res = miniflac_streaminfo_total_samples(
+        flac_.get(), reinterpret_cast<const uint8_t*>(buf.data()),
+        buf.size_bytes(), &bytes_used, &total_samples);
+    return bytes_used;
+  });
+
+  if (res != MINIFLAC_OK) {
+    return cpp::fail(Error::kMalformedData);
+  }
+
+  if (channels == 0 || channels > 2) {
+    return cpp::fail(Error::kMalformedData);
+  }
+
+  OutputFormat format{
+      .num_channels = static_cast<uint8_t>(channels),
+      .sample_rate_hz = static_cast<uint32_t>(sample_rate),
+      .total_samples = total_samples * channels,
+  };
+
+  return format;
+}
+
+auto MiniFlacDecoder::DecodeTo(cpp::span<sample::Sample> output)
+    -> cpp::result<OutputInfo, Error> {
+  bool is_eof = false;
+
+  if (!current_sample_) {
+    MINIFLAC_RESULT res = MINIFLAC_CONTINUE;
+    while (res == MINIFLAC_CONTINUE && !is_eof) {
+      is_eof = buffer_.Refill(input_.get());
+      buffer_.ConsumeBytes([&](cpp::span<std::byte> buf) -> size_t {
+        // FIXME: We should do a miniflac_sync first, in order to check that
+        // our sample buffers have enough space for the next frame.
+        uint32_t bytes_read = 0;
+        res = miniflac_decode(
+            flac_.get(), reinterpret_cast<const uint8_t*>(buf.data()),
+            buf.size_bytes(), &bytes_read, samples_by_channel_.data());
+        return bytes_read;
+      });
+    }
+
+    if (res == MINIFLAC_OK) {
+      current_sample_ = 0;
+    } else if (is_eof) {
+      return OutputInfo{
+          .samples_written = 0,
+          .is_stream_finished = true,
+      };
+    } else {
+      return cpp::fail(Error::kMalformedData);
+    }
+  }
+
+  size_t samples_written = 0;
+  if (current_sample_) {
+    const uint8_t shift = flac_->frame.header.bps - 16;
+
+    while (*current_sample_ < flac_->frame.header.block_size) {
+      if (samples_written + flac_->frame.header.channels >= output.size()) {
+        // We can't fit the next full PCM frame into the buffer.
+        return OutputInfo{.samples_written = samples_written,
+                          .is_stream_finished = false};
+      }
+
+      for (int channel = 0; channel < flac_->frame.header.channels; channel++) {
+        output[samples_written++] = sample::FromSigned(
+            samples_by_channel_[channel][*current_sample_] >> shift, 16);
+      }
+      (*current_sample_)++;
+    }
+  }
+
+  current_sample_.reset();
+  return OutputInfo{.samples_written = samples_written,
+                    .is_stream_finished = samples_written == 0 && is_eof};
+}
+
+auto MiniFlacDecoder::SeekTo(size_t target) -> cpp::result<void, Error> {
+  return {};
+}
+
+}  // namespace codecs