9.8
  $   Sˆl–ßi~”ªhŠjàž¸ÛJbÑ¿Ü„->ÏÀÚ ?÷     S/**
 * \file        lzma/index.h
 * \brief       Handling of .xz Index and related information
 */

/*
 * Author: Lasse Collin
 *
 * This file has been put into the public domain.
 * You can do whatever you want with this file.
 *
 * See ../lzma.h for information about liblzma as a whole.
 */

#ifndef LZMA_H_INTERNAL
#	error Never include this file directly. Use <lzma.h> instead.
#endif


/**
 * \brief       Opaque data type to hold the Index(es) and other information
 *
 * lzma_index often holds just one .xz Index and possibly the Stream Flags
 * of the same Stream and size of the Stream Padding field. However,
 * multiple lzma_indexes can be concatenated with lzma_index_cat() and then
 * there may be information about multiple Streams in the same lzma_index.
 *
 * Notes about thread safety: Only one thread may modify lzma_index at
 * a time. All functions that take non-const pointer to lzma_index
 * modify it. As long as no thread is modifying the lzma_index, getting
 * information from the same lzma_index can be done from multiple threads
 * at the same time with functions that take a const pointer to
 * lzma_index or use lzma_index_iter. The same iterator must be used
 * only by one thread at a time, of course, but there can be as many
 * iterators for the same lzma_index as needed.
 */
typedef struct lzma_index_s lzma_index;


/**
 * \brief       Iterator to get information about Blocks and Streams
 */
typedef struct {
	struct {
		/**
		 * \brief       Pointer to Stream Flags
		 *
		 * This is NULL if Stream Flags have not been set for
		 * this Stream with lzma_index_stream_flags().
		 */
		const lzma_stream_flags *flags;

		const void *reserved_ptr1;
		const void *reserved_ptr2;
		const void *reserved_ptr3;

		/**
		 * \brief       Stream number in the lzma_index
		 *
		 * The first Stream is 1.
		 */
		lzma_vli number;

		/**
		 * \brief       Number of Blocks in the Stream
		 *
		 * If this is zero, the block structure below has
		 * undefined values.
		 */
		lzma_vli block_count;

		/**
		 * \brief       Compressed start offset of this Stream
		 *
		 * The offset is relative to the beginning of the lzma_index
		 * (i.e. usually the beginning of the .xz file).
		 */
		lzma_vli compressed_offset;

		/**
		 * \brief       Uncompressed start offset of this Stream
		 *
		 * The offset is relative to the beginning of the lzma_index
		 * (i.e. usually the beginning of the .xz file).
		 */
		lzma_vli uncompressed_offset;

		/**
		 * \brief       Compressed size of this Stream
		 *
		 * This includes all headers except the possible
		 * Stream Padding after this Stream.
		 */
		lzma_vli compressed_size;

		/**
		 * \brief       Uncompressed size of this Stream
		 */
		lzma_vli uncompressed_size;

		/**
		 * \brief       Size of Stream Padding after this Stream
		 *
		 * If it hasn't been set with lzma_index_stream_padding(),
		 * this defaults to zero. Stream Padding is always
		 * a multiple of four bytes.
		 */
		lzma_vli padding;

		lzma_vli reserved_vli1;
		lzma_vli reserved_vli2;
		lzma_vli reserved_vli3;
		lzma_vli reserved_vli4;
	} stream;

	struct {
		/**
		 * \brief       Block number in the file
		 *
		 * The first Block is 1.
		 */
		lzma_vli number_in_file;

		/**
		 * \brief       Compressed start offset of this Block
		 *
		 * This offset is relative to the beginning of the
		 * lzma_index (i.e. usually the beginning of the .xz file).
		 * Normally this is where you should seek in the .xz file
		 * to start decompressing this Block.
		 */
		lzma_vli compressed_file_offset;

		/**
		 * \brief       Uncompressed start offset of this Block
		 *
		 * This offset is relative to the beginning of the lzma_index
		 * (i.e. usually the beginning of the .xz file).
		 *
		 * When doing random-access reading, it is possible that
		 * the target offset is not exactly at Block boundary. One
		 * will need to compare the target offset against
		 * uncompressed_file_offset or uncompressed_stream_offset,
		 * and possibly decode and throw away some amount of data