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index.h
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/** * \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 * before reaching the target offset. */ lzma_vli uncompressed_file_offset; /** * \brief Block number in this Stream * * The first Block is 1. */ lzma_vli number_in_stream; /** * \brief Compressed start offset of this Block * * This offset is relative to the beginning of the Stream * containing this Block. */ lzma_vli compressed_stream_offset; /** * \brief Uncompressed start offset of this Block * * This offset is relative to the beginning of the Stream * containing this Block. */ lzma_vli uncompressed_stream_offset; /** * \brief Uncompressed size of this Block * * You should pass this to the Block decoder if you will * decode this Block. It will allow the Block decoder to * validate the uncompressed size. */ lzma_vli uncompressed_size; /** * \brief Unpadded size of this Block * * You should pass this to the Block decoder if you will * decode this Block. It will allow the Block decoder to * validate the unpadded size. */ lzma_vli unpadded_size; /** * \brief Total compressed size * * This includes all headers and padding in this Block. * This is useful if you need to know how many bytes * the Block decoder will actually read. */ lzma_vli total_size; lzma_vli reserved_vli1; lzma_vli reserved_vli2; lzma_vli reserved_vli3; lzma_vli reserved_vli4; const void *reserved_ptr1; const void *reserved_ptr2; const void *reserved_ptr3; const void *reserved_ptr4; } block; /* * Internal data which is used to store the state of the iterator. * The exact format may vary between liblzma versions, so don't * touch these in any way. */ union { const void *p; size_t s; lzma_vli v; } internal[6]; } lzma_index_iter; /** * \brief Operation mode for lzma_index_iter_next() */ typedef enum { LZMA_INDEX_ITER_ANY = 0, /**< * \brief Get the next Block or Stream * * Go to the next Block if the current Stream has at least * one Block left. Otherwise go to the next Stream even if * it has no Blocks. If the Stream has no Blocks * (lzma_index_iter.stream.block_count == 0), * lzma_index_iter.block will have undefined values. */ LZMA_INDEX_ITER_STREAM = 1, /**< * \brief Get the next Stream * * Go to the next Stream even if the current Stream has * unread Blocks left. If the next Stream has at least one * Block, the iterator will point to the first Block. * If there are no Blocks, lzma_index_iter.block will have * undefined values. */ LZMA_INDEX_ITER_BLOCK = 2, /**< * \brief Get the next Block * * Go to the next Block if the current Stream has at least * one Block left. If the current Stream has no Blocks left, * the next Stream with at least one Block is located and * the iterator will be made to point to the first Block of * that Stream. */ LZMA_INDEX_ITER_NONEMPTY_BLOCK = 3 /**< * \brief Get the next non-empty Block * * This is like LZMA_INDEX_ITER_BLOCK except that it will * skip Blocks whose Uncompressed Size is zero. */ } lzma_index_iter_mode; /** * \brief Calculate memory usage of lzma_index * * On disk, the size of the Index field depends on both the number of Records * stored and how big values the Records store (due to variable-length integer * encoding). When the Index is kept in lzma_index structure, the memory usage * depends only on the number of Records/Blocks stored in the Index(es), and * in case of concatenated lzma_indexes, the number of Streams. The size in * RAM is almost always significantly bigger than in the encoded form on disk. * * This function calculates an approximate amount of memory needed hold * the given number of Streams and Blocks in lzma_index structure. This * value may vary between CPU architectures and also between liblzma versions * if the internal implementation is modified. */ extern LZMA_API(uint64_t) lzma_index_memusage( lzma_vli streams, lzma_vli blocks) lzma_nothrow; /** * \brief Calculate the memory usage of an existing lzma_index * * This is a shorthand for lzma_index_memusage(lzma_index_stream_count(i), * lzma_index_block_count(i)). */ extern LZMA_API(uint64_t) lzma_index_memused(const lzma_index *i) lzma_nothrow; /** * \brief Allocate and initialize a new lzma_index structure * * \return On success, a pointer to an empty initialized lzma_index is * returned. If allocation fails, NULL is returned. */ extern LZMA_API(lzma_index *) lzma_index_init(const lzma_allocator *allocator) lzma_nothrow; /** * \brief Deallocate lzma_index * * If i is NULL, this does nothing. */ extern LZMA_API(void) lzma_index_end( lzma_index *i, const lzma_allocator *allocator) lzma_nothrow; /** * \brief Add a new Block to lzma_index * * \param i Pointer to a lzma_index structure * \param allocator Pointer to lzma_allocator, or NULL to * use malloc() * \param unpadded_size Unpadded Size of a Block. This can be * calculated with lzma_block_unpadded_size() * after encoding or decoding the Block. * \param uncompressed_size Uncompressed Size of a Block. This can be * taken directly from lzma_block structure * after encoding or decoding the Block. * * Appending a new Block does not invalidate iterators. For example, * if an iterator was pointing to the end of the lzma_index, after * lzma_index_append() it is possible to read the next Block with * an existing iterator. * * \return - LZMA_OK * - LZMA_MEM_ERROR * - LZMA_DATA_ERROR: Compressed or uncompressed size of the * Stream or size of the Index field would grow too big. * - LZMA_PROG_ERROR */ extern LZMA_API(lzma_ret) lzma_index_append( lzma_index *i, const lzma_allocator *allocator, lzma_vli unpadded_size, lzma_vli uncompressed_size) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Set the Stream Flags * * Set the Stream Flags of the last (and typically the only) Stream * in lzma_index. This can be useful when reading information from the * lzma_index, because to decode Blocks, knowing the integrity check type * is needed. * * The given Stream Flags are copied into internal preallocated structure * in the lzma_index, thus the caller doesn't need to keep the *stream_flags * available after calling this function. * * \return - LZMA_OK * - LZMA_OPTIONS_ERROR: Unsupported stream_flags->version. * - LZMA_PROG_ERROR */ extern LZMA_API(lzma_ret) lzma_index_stream_flags( lzma_index *i, const lzma_stream_flags *stream_flags) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Get the types of integrity Checks * * If lzma_index_stream_flags() is used to set the Stream Flags for * every Stream, lzma_index_checks() can be used to get a bitmask to * indicate which Check types have been used. It can be useful e.g. if * showing the Check types to the user. * * The bitmask is 1 << check_id, e.g. CRC32 is 1 << 1 and SHA-256 is 1 << 10. */ extern LZMA_API(uint32_t) lzma_index_checks(const lzma_index *i) lzma_nothrow lzma_attr_pure; /** * \brief Set the amount of Stream Padding * * Set the amount of Stream Padding of the last (and typically the only) * Stream in the lzma_index. This is needed when planning to do random-access * reading within multiple concatenated Streams. * * By default, the amount of Stream Padding is assumed to be zero bytes. * * \return - LZMA_OK * - LZMA_DATA_ERROR: The file size would grow too big. * - LZMA_PROG_ERROR */ extern LZMA_API(lzma_ret) lzma_index_stream_padding( lzma_index *i, lzma_vli stream_padding) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Get the number of Streams */ extern LZMA_API(lzma_vli) lzma_index_stream_count(const lzma_index *i) lzma_nothrow lzma_attr_pure; /** * \brief Get the number of Blocks * * This returns the total number of Blocks in lzma_index. To get number * of Blocks in individual Streams, use lzma_index_iter. */ extern LZMA_API(lzma_vli) lzma_index_block_count(const lzma_index *i) lzma_nothrow lzma_attr_pure; /** * \brief Get the size of the Index field as bytes * * This is needed to verify the Backward Size field in the Stream Footer. */ extern LZMA_API(lzma_vli) lzma_index_size(const lzma_index *i) lzma_nothrow lzma_attr_pure; /** * \brief Get the total size of the Stream * * If multiple lzma_indexes have been combined, this works as if the Blocks * were in a single Stream. This is useful if you are going to combine * Blocks from multiple Streams into a single new Stream. */ extern LZMA_API(lzma_vli) lzma_index_stream_size(const lzma_index *i) lzma_nothrow lzma_attr_pure; /** * \brief Get the total size of the Blocks * * This doesn't include the Stream Header, Stream Footer, Stream Padding, * or Index fields. */ extern LZMA_API(lzma_vli) lzma_index_total_size(const lzma_index *i) lzma_nothrow lzma_attr_pure; /** * \brief Get the total size of the file * * When no lzma_indexes have been combined with lzma_index_cat() and there is * no Stream Padding, this function is identical to lzma_index_stream_size(). * If multiple lzma_indexes have been combined, this includes also the headers * of each separate Stream and the possible Stream Padding fields. */ extern LZMA_API(lzma_vli) lzma_index_file_size(const lzma_index *i) lzma_nothrow lzma_attr_pure; /** * \brief Get the uncompressed size of the file */ extern LZMA_API(lzma_vli) lzma_index_uncompressed_size(const lzma_index *i) lzma_nothrow lzma_attr_pure; /** * \brief Initialize an iterator * * \param iter Pointer to a lzma_index_iter structure * \param i lzma_index to which the iterator will be associated * * This function associates the iterator with the given lzma_index, and calls * lzma_index_iter_rewind() on the iterator. * * This function doesn't allocate any memory, thus there is no * lzma_index_iter_end(). The iterator is valid as long as the * associated lzma_index is valid, that is, until lzma_index_end() or * using it as source in lzma_index_cat(). Specifically, lzma_index doesn't * become invalid if new Blocks are added to it with lzma_index_append() or * if it is used as the destination in lzma_index_cat(). * * It is safe to make copies of an initialized lzma_index_iter, for example, * to easily restart reading at some particular position. */ extern LZMA_API(void) lzma_index_iter_init( lzma_index_iter *iter, const lzma_index *i) lzma_nothrow; /** * \brief Rewind the iterator * * Rewind the iterator so that next call to lzma_index_iter_next() will * return the first Block or Stream. */ extern LZMA_API(void) lzma_index_iter_rewind(lzma_index_iter *iter) lzma_nothrow; /** * \brief Get the next Block or Stream * * \param iter Iterator initialized with lzma_index_iter_init() * \param mode Specify what kind of information the caller wants * to get. See lzma_index_iter_mode for details. * * \return If next Block or Stream matching the mode was found, *iter * is updated and this function returns false. If no Block or * Stream matching the mode is found, *iter is not modified * and this function returns true. If mode is set to an unknown * value, *iter is not modified and this function returns true. */ extern LZMA_API(lzma_bool) lzma_index_iter_next( lzma_index_iter *iter, lzma_index_iter_mode mode) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Locate a Block * * If it is possible to seek in the .xz file, it is possible to parse * the Index field(s) and use lzma_index_iter_locate() to do random-access * reading with granularity of Block size. * * \param iter Iterator that was earlier initialized with * lzma_index_iter_init(). * \param target Uncompressed target offset which the caller would * like to locate from the Stream * * If the target is smaller than the uncompressed size of the Stream (can be * checked with lzma_index_uncompressed_size()): * - Information about the Stream and Block containing the requested * uncompressed offset is stored into *iter. * - Internal state of the iterator is adjusted so that * lzma_index_iter_next() can be used to read subsequent Blocks or Streams. * - This function returns false. * * If target is greater than the uncompressed size of the Stream, *iter * is not modified, and this function returns true. */ extern LZMA_API(lzma_bool) lzma_index_iter_locate( lzma_index_iter *iter, lzma_vli target) lzma_nothrow; /** * \brief Concatenate lzma_indexes * * Concatenating lzma_indexes is useful when doing random-access reading in * multi-Stream .xz file, or when combining multiple Streams into single * Stream. * * \param dest lzma_index after which src is appended * \param src lzma_index to be appended after dest. If this * function succeeds, the memory allocated for src * is freed or moved to be part of dest, and all * iterators pointing to src will become invalid. * \param allocator Custom memory allocator; can be NULL to use * malloc() and free(). * * \return - LZMA_OK: lzma_indexes were concatenated successfully. * src is now a dangling pointer. * - LZMA_DATA_ERROR: *dest would grow too big. * - LZMA_MEM_ERROR * - LZMA_PROG_ERROR */ extern LZMA_API(lzma_ret) lzma_index_cat(lzma_index *dest, lzma_index *src, const lzma_allocator *allocator) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Duplicate lzma_index * * \return A copy of the lzma_index, or NULL if memory allocation failed. */ extern LZMA_API(lzma_index *) lzma_index_dup( const lzma_index *i, const lzma_allocator *allocator) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Initialize .xz Index encoder * * \param strm Pointer to properly prepared lzma_stream * \param i Pointer to lzma_index which should be encoded. * * The valid `action' values for lzma_code() are LZMA_RUN and LZMA_FINISH. * It is enough to use only one of them (you can choose freely). * * \return - LZMA_OK: Initialization succeeded, continue with lzma_code(). * - LZMA_MEM_ERROR * - LZMA_PROG_ERROR */ extern LZMA_API(lzma_ret) lzma_index_encoder( lzma_stream *strm, const lzma_index *i) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Initialize .xz Index decoder * * \param strm Pointer to properly prepared lzma_stream * \param i The decoded Index will be made available via * this pointer. Initially this function will * set *i to NULL (the old value is ignored). If * decoding succeeds (lzma_code() returns * LZMA_STREAM_END), *i will be set to point * to a new lzma_index, which the application * has to later free with lzma_index_end(). * \param memlimit How much memory the resulting lzma_index is * allowed to require. liblzma 5.2.3 and earlier * don't allow 0 here and return LZMA_PROG_ERROR; * later versions treat 0 as if 1 had been specified. * * Valid `action' arguments to lzma_code() are LZMA_RUN and LZMA_FINISH. * There is no need to use LZMA_FINISH, but it's allowed because it may * simplify certain types of applications. * * \return - LZMA_OK: Initialization succeeded, continue with lzma_code(). * - LZMA_MEM_ERROR * - LZMA_PROG_ERROR * * liblzma 5.2.3 and older list also LZMA_MEMLIMIT_ERROR here * but that error code has never been possible from this * initialization function. */ extern LZMA_API(lzma_ret) lzma_index_decoder( lzma_stream *strm, lzma_index **i, uint64_t memlimit) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Single-call .xz Index encoder * * \param i lzma_index to be encoded * \param out Beginning of the output buffer * \param out_pos The next byte will be written to out[*out_pos]. * *out_pos is updated only if encoding succeeds. * \param out_size Size of the out buffer; the first byte into * which no data is written to is out[out_size]. * * \return - LZMA_OK: Encoding was successful. * - LZMA_BUF_ERROR: Output buffer is too small. Use * lzma_index_size() to find out how much output * space is needed. * - LZMA_PROG_ERROR * * \note This function doesn't take allocator argument since all * the internal data is allocated on stack. */ extern LZMA_API(lzma_ret) lzma_index_buffer_encode(const lzma_index *i, uint8_t *out, size_t *out_pos, size_t out_size) lzma_nothrow; /** * \brief Single-call .xz Index decoder * * \param i If decoding succeeds, *i will point to a new * lzma_index, which the application has to * later free with lzma_index_end(). If an error * occurs, *i will be NULL. The old value of *i * is always ignored and thus doesn't need to be * initialized by the caller. * \param memlimit Pointer to how much memory the resulting * lzma_index is allowed to require. The value * pointed by this pointer is modified if and only * if LZMA_MEMLIMIT_ERROR is returned. * \param allocator Pointer to lzma_allocator, or NULL to use malloc() * \param in Beginning of the input buffer * \param in_pos The next byte will be read from in[*in_pos]. * *in_pos is updated only if decoding succeeds. * \param in_size Size of the input buffer; the first byte that * won't be read is in[in_size]. * * \return - LZMA_OK: Decoding was successful. * - LZMA_MEM_ERROR * - LZMA_MEMLIMIT_ERROR: Memory usage limit was reached. * The minimum required memlimit value was stored to *memlimit. * - LZMA_DATA_ERROR * - LZMA_PROG_ERROR */ extern LZMA_API(lzma_ret) lzma_index_buffer_decode(lzma_index **i, uint64_t *memlimit, const lzma_allocator *allocator, const uint8_t *in, size_t *in_pos, size_t in_size) lzma_nothrow;
