1 files changed, 259 insertions, 0 deletions
diff --git a/src/codecs/wav.cpp b/src/codecs/wav.cpp
new file mode 100644
index 00000000..a67f3ff4
--- /dev/null
+++ b/src/codecs/wav.cpp
@@ -0,0 +1,259 @@
+/*
+ * Copyright 2023 Daniel <ailuruxx@gmail.com>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "wav.hpp"
+#include <stdint.h>
+#include <sys/_stdint.h>
+
+#include <algorithm>
+#include <cstdlib>
+#include <string>
+
+#include "debug.hpp"
+#include "esp_log.h"
+#include "sample.hpp"
+
+namespace codecs {
+
+[[maybe_unused]] static const char kTag[] = "wav";
+
+static inline auto bytes_to_u16(cpp::span<std::byte const, 2> bytes)
+    -> uint16_t {
+  return (uint16_t)bytes[0] | (uint16_t)bytes[1] << 8;
+}
+
+static inline auto bytes_to_u32(cpp::span<std::byte const, 4> bytes)
+    -> uint32_t {
+  return (uint32_t)bytes[0] | (uint32_t)bytes[1] << 8 |
+         (uint32_t)bytes[2] << 16 | (uint32_t)bytes[3] << 24;
+}
+
+static inline auto bytes_to_str(cpp::span<std::byte const> bytes)
+    -> std::string {
+  return std::string(reinterpret_cast<const char*>(bytes.data()),
+                    bytes.size_bytes());
+}
+
+static int16_t convert_f32_to_16_bit(cpp::span<const std::byte> bytes) {
+  uint64_t val = 0;
+  val = (uint8_t)bytes[3];
+  val = (val << 8) | (uint8_t)bytes[2];
+  val = (val << 8) | (uint8_t)bytes[1];
+  val = (val << 8) | (uint8_t)bytes[0];
+  // Isolate the sign and remove from the value
+  uint64_t sign = val >> 31;
+  val -= (sign << 31);
+  // Isolate the exponent and remove from the value
+  uint64_t exp = (val >> 23);
+  val -= (exp << 23);
+  // Remove old bias and add new bias
+  exp = exp - 127 + 1023;
+  // Reconstruct the bits in the correct order and convert to double
+  uint64_t dval = (sign << 63) + (exp << 52) + (val << 29);
+  double* fval = reinterpret_cast<double*>(&dval);
+  return sample::FromDouble(*fval);
+}
+
+static int16_t convert_to_16_bit(cpp::span<const std::byte> bytes) {
+  int depth = bytes.size();
+  int32_t val = 0;
+  // If 8-bit Assume Unsigned
+  if (depth == 1) {
+    return sample::FromUnsigned((uint8_t)bytes[0], 8);
+  }
+  // Otherwise, build the signed int of the right depth
+  switch (depth) {
+    case 4:
+      val = (uint8_t)bytes[3];
+    case 3:
+      val = (val << 8) | (uint8_t)bytes[2];
+    case 2:
+      val = (val << 8) | (uint8_t)bytes[1];
+    case 1:
+      val = (val << 8) | (uint8_t)bytes[0];
+  }
+  // Convert to sample
+  int16_t result = sample::FromSigned(val, depth * 8);
+  return result;
+}
+
+WavDecoder::WavDecoder() : input_(), buffer_() {}
+
+WavDecoder::~WavDecoder() {}
+
+auto WavDecoder::OpenStream(std::shared_ptr<IStream> input)
+    -> cpp::result<OutputFormat, Error> {
+  input_ = input;
+
+  std::array<std::byte, 255> buf{std::byte{0}};
+  auto size = input->Read(buf);
+  if (size < 44) {
+    return cpp::fail(Error::kOutOfInput);
+  }
+
+  // - check the first 4 bytes = 'RIFF'
+  // - next 4 bytes = file size
+  // - check next 4 bytes = 'WAVE'
+  // - index of 'fmt\0' (i) marks start of fmt data
+  // - i + 4 = size of fmt header (16, 18 or 40)
+  // - i + 8 = format (should be 0x01 for pcm, 0xfffe for
+  // wave_format_exstensible)
+  // - i + 10 = num channels
+  // - i + 12 = sample rate
+  // - i + 16 = byte rate (sample rate * channels * bits per sample / 8)
+  // - i + 20 = sample size (bits per sample * channels / 8)
+  // - i + 22 = bits per sample (2 bytes)
+  // - end of this part, next header we care about is 'data'
+  // - and then the next 4 bytes = 32 bit int = size of data
+
+  auto buffer_span = cpp::span{buf};
+
+  std::string riff = bytes_to_str(buffer_span.subspan(0, 4));
+  if (riff != "RIFF") {
+    ESP_LOGW(kTag, "file is not RIFF");
+    return cpp::fail(Error::kMalformedData);
+  }
+
+  uint32_t file_size = bytes_to_u32(buffer_span.subspan(4, 4)) + 8;
+
+  std::string fmt_header = bytes_to_str(buffer_span.subspan(12, 4));
+  ESP_LOGI(kTag, "fmt header found? %s",
+           (fmt_header.starts_with("fmt")) ? "yes" : "no");
+  if (!fmt_header.starts_with("fmt")) {
+    ESP_LOGW(kTag, "Could not find format chunk");
+    return cpp::fail(Error::kMalformedData);
+  }
+
+  // Size of the fmt header, should be 16, 18 or 40
+  uint32_t fmt_header_size = bytes_to_u32(buffer_span.subspan(16, 4));
+
+  wave_format_ = bytes_to_u16(buffer_span.subspan(20, 2));
+  if (wave_format_ == kWaveFormatPCM) {
+    ESP_LOGD(kTag, "wave format: PCM");
+  } else if (wave_format_ == kWaveFormatExtensible) {
+    ESP_LOGD(kTag, "wave format: extensible");
+  } else if (wave_format_ == kWaveFormatIEEEFloat) {
+    ESP_LOGD(kTag, "wave format: IEEE Float");
+  } else {
+    ESP_LOGW(kTag, "WAVE format not supported");
+    return cpp::fail(Error::kUnsupportedFormat);
+  }
+
+  num_channels_ = bytes_to_u16(buffer_span.subspan(22, 2));
+
+  uint32_t samples_per_second = bytes_to_u32(buffer_span.subspan(24, 4));
+
+  uint32_t avg_bytes_per_second = bytes_to_u32(buffer_span.subspan(28, 4));
+
+  uint16_t block_align = bytes_to_u16(buffer_span.subspan(32, 2));
+
+  bytes_per_sample_ = block_align / num_channels_;
+
+  uint16_t bits_per_sample = bytes_to_u16(buffer_span.subspan(34, 2));
+
+  // find the start of the data chunk
+  std::array<std::byte, 4> data_tag = {std::byte{0x64}, std::byte{0x61},
+                                       std::byte{0x74}, std::byte{0x61}};
+  auto data_loc = std::ranges::search(buffer_span, data_tag);
+  if (data_loc.begin() == buffer_span.end()) {
+    ESP_LOGW(kTag, "Could not find data chunk!");
+    return cpp::fail(Error::kMalformedData);
+  }
+
+  int data_chunk_index = std::distance(buffer_span.begin(), data_loc.begin());
+
+  uint32_t data_chunk_size =
+      bytes_to_u32(buffer_span.subspan(data_chunk_index + 4, 4));
+
+  // calculate number of samples
+  int number_of_samples = data_chunk_size / bytes_per_sample_;
+
+  // extension to the fmt chunk size (0 or 22)
+  uint16_t extension_size = 0;
+  if (wave_format_ == kWaveFormatExtensible) {
+    extension_size = bytes_to_u16(buffer_span.subspan(36, 2));
+  }
+
+  // Parse extension if applicable
+  if (extension_size == 22) {
+    // Valid bits per sample
+    uint16_t valid_bits_per_sample = bytes_to_u16(buffer_span.subspan(38, 2));
+
+    uint32_t speaker_mask = bytes_to_u32(buffer_span.subspan(40, 4));
+
+    // Parse subformat
+    subformat_ = bytes_to_u16(buffer_span.subspan(44, 2));
+    if (!(subformat_ == kWaveFormatPCM ||
+          subformat_ == kWaveFormatIEEEFloat)) {
+      ESP_LOGW(kTag, "WAVE extensible subformat_ not supported");
+      return cpp::fail(Error::kUnsupportedFormat);
+    }
+  }
+
+  // 64 bit float is not implemented yet, make sure we're not letting it through
+  if (GetFormat() == kWaveFormatIEEEFloat && bytes_per_sample_ == 8) {
+    ESP_LOGW(kTag, "WAVE 64-Bit Float not supported");
+    return cpp::fail(Error::kUnsupportedFormat);
+  }
+
+  // Seek track to start of data
+  input->SeekTo(data_chunk_index + 8, IStream::SeekFrom::kStartOfStream);
+
+  output_format_ = {.num_channels = (uint8_t)num_channels_,
+                    .sample_rate_hz = samples_per_second,
+                    .total_samples = number_of_samples};
+
+  return output_format_;
+}
+
+auto WavDecoder::DecodeTo(cpp::span<sample::Sample> output)
+    -> cpp::result<OutputInfo, Error> {
+  bool is_eof = buffer_.Refill(input_.get());
+  size_t samples_written = 0;
+
+  buffer_.ConsumeBytes([&](cpp::span<std::byte> buf) -> size_t {
+    size_t bytes_read = buf.size_bytes();
+    size_t frames_read =
+        bytes_read / bytes_per_sample_ / output_format_.num_channels;
+
+    samples_written =
+        std::min<size_t>(frames_read,
+                         output.size() / output_format_.num_channels) *
+        output_format_.num_channels;
+
+    // For each sample that we're going to write
+    for (size_t i = 0; i < samples_written; i++) {
+      auto data = buf.subspan(i * bytes_per_sample_, bytes_per_sample_);
+      if (GetFormat() == kWaveFormatPCM) {
+        // PCM
+        output[i] = convert_to_16_bit(data);
+      } else if (GetFormat() == kWaveFormatIEEEFloat) {
+        // 32-Bit Float
+        if (bytes_per_sample_ == 4) {
+          output[i] = convert_f32_to_16_bit(data);
+        }
+      }
+    }
+
+    return samples_written * bytes_per_sample_;
+  });
+
+  return OutputInfo{.samples_written = samples_written,
+                    .is_stream_finished = samples_written == 0 && is_eof};
+}
+
+auto WavDecoder::SeekTo(size_t target) -> cpp::result<void, Error> {
+  return {};
+}
+
+auto codecs::WavDecoder::GetFormat() const -> uint16_t {
+  if (wave_format_ == kWaveFormatExtensible) {
+    return subformat_;
+  }
+  return wave_format_;
+}
+
+}  // namespace codecs