Class BufferExtent

runtime/Log.h:264–292

* Marker in the compressed log that indicates to which StagingBuffer/thread * the next contiguous chunk of LOG_MSG's belong to (up to the next * BufferExtent marker). These markers correspond to when the compression * thread finishes processing a peek() and moves on to outputting the next * StagingBuffer. */

     * StagingBuffer.
     */
    struct BufferExtent {
        // Byte representation of EntryType::BUFFER_EXTENT
        uint8_t entryType:2;

        // Indicates that the BufferChange also corresponds with a complete
        // pass through all the StagingBuffers at runtime. This information can
        // be used to determine the maximal temporal reordering that can occur
        // in the linear compressed log.
        uint8_t wrapAround:1;

        // A value of 1 indicates the next 4 bits are a threadId, else
        // the next 4 bits are the 4-bit result of a pack() operation.
        uint8_t isShort:1;

        // Value is either a 4-bit threadId or a Pack() result used to compact
        // the thread id that comes after this header.
        uint8_t threadIdOrPackNibble:4;

        // Indicates the byte size of the extent. This value is purposely
        // left unpack()-ed in-order to allow for delayed assignment (i.e.
        // after all the log messages have been processed).
        uint32_t length;

        // Returns the maximum size the BufferChange structure can be with
        // the Pack()-ed arguments.
        static constexpr uint32_t maxSizeOfHeader() {
            return sizeof(BufferExtent) + sizeof(uint32_t);
        }
    } __attribute__((packed));

    /**
     * Synchronization data structure in the compressed log that correlates the