Add code to xz-compress log files
Change-Id: I2e00c8aa316f5907f7f9bc1a4653b1f7c793a876
diff --git a/aos/events/logging/lzma_encoder.h b/aos/events/logging/lzma_encoder.h
new file mode 100644
index 0000000..d7080a9
--- /dev/null
+++ b/aos/events/logging/lzma_encoder.h
@@ -0,0 +1,72 @@
+#ifndef AOS_EVENTS_LOGGING_LZMA_ENCODER_H_
+#define AOS_EVENTS_LOGGING_LZMA_ENCODER_H_
+
+#include "absl/types/span.h"
+#include "flatbuffers/flatbuffers.h"
+#include "lzma.h"
+
+#include "aos/containers/resizeable_buffer.h"
+#include "aos/events/logging/buffer_encoder.h"
+#include "aos/events/logging/logger_generated.h"
+
+namespace aos::logger {
+
+// Encodes buffers using liblzma.
+class LzmaEncoder final : public DetachedBufferEncoder {
+ public:
+ // Initializes the LZMA stream and encoder.
+ explicit LzmaEncoder(uint32_t compression_preset);
+ // Gracefully shuts down the encoder.
+ ~LzmaEncoder() final;
+
+ void Encode(flatbuffers::DetachedBuffer &&in) final;
+ void Finish() final;
+ void Clear(int n) final;
+ std::vector<absl::Span<const uint8_t>> queue() const final;
+ size_t queued_bytes() const final;
+ size_t total_bytes() const final { return total_bytes_; }
+ size_t queue_size() const final { return queue_.size(); }
+
+ private:
+ static constexpr size_t kEncodedBufferSizeBytes{1024};
+
+ void RunLzmaCode(lzma_action action);
+
+ lzma_stream stream_;
+ uint32_t compression_preset_;
+ std::vector<ResizeableBuffer> queue_;
+ bool finished_ = false;
+ // Total bytes that resulted from encoding raw data since the last call to
+ // Reset.
+ size_t total_bytes_ = 0;
+};
+
+// Decompresses data with liblzma.
+class LzmaDecoder final : public DataDecoder {
+ public:
+ explicit LzmaDecoder(std::string_view filename);
+ ~LzmaDecoder();
+
+ size_t Read(uint8_t *begin, uint8_t *end) final;
+
+ private:
+ // Size of temporary buffer to use.
+ static constexpr size_t kBufSize{256 * 1024};
+
+ // Temporary buffer for storing compressed data.
+ ResizeableBuffer compressed_data_;
+ // Used for reading data from the file.
+ DummyDecoder dummy_decoder_;
+ // Stream for decompression.
+ lzma_stream stream_;
+ // The current action. This is LZMA_RUN until we've run out of data to read
+ // from the file.
+ lzma_action action_ = LZMA_RUN;
+ // Flag that represents whether or not all the data from the file has been
+ // successfully decoded.
+ bool finished_ = false;
+};
+
+} // namespace aos::logger
+
+#endif // AOS_EVENTS_LOGGING_LZMA_ENCODER_H_