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편집 파일: block.h

/** * \file lzma/block.h * \brief .xz Block handling */ /* * 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 Options for the Block and Block Header encoders and decoders * * Different Block handling functions use different parts of this structure. * Some read some members, other functions write, and some do both. Only the * members listed for reading need to be initialized when the specified * functions are called. The members marked for writing will be assigned * new values at some point either by calling the given function or by * later calls to lzma_code(). */ typedef struct { /** * \brief Block format version * * To prevent API and ABI breakages when new features are needed, * a version number is used to indicate which fields in this * structure are in use: * - liblzma >= 5.0.0: version = 0 is supported. * - liblzma >= 5.1.4beta: Support for version = 1 was added, * which adds the ignore_check field. * * If version is greater than one, most Block related functions * will return LZMA_OPTIONS_ERROR (lzma_block_header_decode() works * with any version value). * * Read by: * - All functions that take pointer to lzma_block as argument, * including lzma_block_header_decode(). * * Written by: * - lzma_block_header_decode() */ uint32_t version; /** * \brief Size of the Block Header field * * This is always a multiple of four. * * Read by: * - lzma_block_header_encode() * - lzma_block_header_decode() * - lzma_block_compressed_size() * - lzma_block_unpadded_size() * - lzma_block_total_size() * - lzma_block_decoder() * - lzma_block_buffer_decode() * * Written by: * - lzma_block_header_size() * - lzma_block_buffer_encode() */ uint32_t header_size; # define LZMA_BLOCK_HEADER_SIZE_MIN 8 # define LZMA_BLOCK_HEADER_SIZE_MAX 1024 /** * \brief Type of integrity Check * * The Check ID is not stored into the Block Header, thus its value * must be provided also when decoding. * * Read by: * - lzma_block_header_encode() * - lzma_block_header_decode() * - lzma_block_compressed_size() * - lzma_block_unpadded_size() * - lzma_block_total_size() * - lzma_block_encoder() * - lzma_block_decoder() * - lzma_block_buffer_encode() * - lzma_block_buffer_decode() */ lzma_check check; /** * \brief Size of the Compressed Data in bytes * * Encoding: If this is not LZMA_VLI_UNKNOWN, Block Header encoder * will store this value to the Block Header. Block encoder doesn't * care about this value, but will set it once the encoding has been * finished. * * Decoding: If this is not LZMA_VLI_UNKNOWN, Block decoder will * verify that the size of the Compressed Data field matches * compressed_size. * * Usually you don't know this value when encoding in streamed mode, * and thus cannot write this field into the Block Header. * * In non-streamed mode you can reserve space for this field before * encoding the actual Block. After encoding the data, finish the * Block by encoding the Block Header. Steps in detail: * * - Set compressed_size to some big enough value. If you don't know * better, use LZMA_VLI_MAX, but remember that bigger values take * more space in Block Header. * * - Call lzma_block_header_size() to see how much space you need to * reserve for the Block Header. * * - Encode the Block using lzma_block_encoder() and lzma_code(). * It sets compressed_size to the correct value. * * - Use lzma_block_header_encode() to encode the Block Header. * Because space was reserved in the first step, you don't need * to call lzma_block_header_size() anymore, because due to * reserving, header_size has to be big enough. If it is "too big", * lzma_block_header_encode() will add enough Header Padding to * make Block Header to match the size specified by header_size. * * Read by: * - lzma_block_header_size() * - lzma_block_header_encode() * - lzma_block_compressed_size() * - lzma_block_unpadded_size() * - lzma_block_total_size() * - lzma_block_decoder() * - lzma_block_buffer_decode() * * Written by: * - lzma_block_header_decode() * - lzma_block_compressed_size() * - lzma_block_encoder() * - lzma_block_decoder() * - lzma_block_buffer_encode() * - lzma_block_buffer_decode() */ lzma_vli compressed_size; /** * \brief Uncompressed Size in bytes * * This is handled very similarly to compressed_size above. * * uncompressed_size is needed by fewer functions than * compressed_size. This is because uncompressed_size isn't * needed to validate that Block stays within proper limits. * * Read by: * - lzma_block_header_size() * - lzma_block_header_encode() * - lzma_block_decoder() * - lzma_block_buffer_decode() * * Written by: * - lzma_block_header_decode() * - lzma_block_encoder() * - lzma_block_decoder() * - lzma_block_buffer_encode() * - lzma_block_buffer_decode() */ lzma_vli uncompressed_size; /** * \brief Array of filters * * There can be 1-4 filters. The end of the array is marked with * .id = LZMA_VLI_UNKNOWN. * * Read by: * - lzma_block_header_size() * - lzma_block_header_encode() * - lzma_block_encoder() * - lzma_block_decoder() * - lzma_block_buffer_encode() * - lzma_block_buffer_decode() * * Written by: * - lzma_block_header_decode(): Note that this does NOT free() * the old filter options structures. All unused filters[] will * have .id == LZMA_VLI_UNKNOWN and .options == NULL. If * decoding fails, all filters[] are guaranteed to be * LZMA_VLI_UNKNOWN and NULL. * * \note Because of the array is terminated with * .id = LZMA_VLI_UNKNOWN, the actual array must * have LZMA_FILTERS_MAX + 1 members or the Block * Header decoder will overflow the buffer. */ lzma_filter *filters; /** * \brief Raw value stored in the Check field * * After successful coding, the first lzma_check_size(check) bytes * of this array contain the raw value stored in the Check field. * * Note that CRC32 and CRC64 are stored in little endian byte order. * Take it into account if you display the Check values to the user. * * Written by: * - lzma_block_encoder() * - lzma_block_decoder() * - lzma_block_buffer_encode() * - lzma_block_buffer_decode() */ uint8_t raw_check[LZMA_CHECK_SIZE_MAX]; /* * Reserved space to allow possible future extensions without * breaking the ABI. You should not touch these, because the names * of these variables may change. These are and will never be used * with the currently supported options, so it is safe to leave these * uninitialized. */ void *reserved_ptr1; void *reserved_ptr2; void *reserved_ptr3; uint32_t reserved_int1; uint32_t reserved_int2; lzma_vli reserved_int3; lzma_vli reserved_int4; lzma_vli reserved_int5; lzma_vli reserved_int6; lzma_vli reserved_int7; lzma_vli reserved_int8; lzma_reserved_enum reserved_enum1; lzma_reserved_enum reserved_enum2; lzma_reserved_enum reserved_enum3; lzma_reserved_enum reserved_enum4; /** * \brief A flag to Block decoder to not verify the Check field * * This field is supported by liblzma >= 5.1.4beta if .version >= 1. * * If this is set to true, the integrity check won't be calculated * and verified. Unless you know what you are doing, you should * leave this to false. (A reason to set this to true is when the * file integrity is verified externally anyway and you want to * speed up the decompression, which matters mostly when using * SHA-256 as the integrity check.) * * If .version >= 1, read by: * - lzma_block_decoder() * - lzma_block_buffer_decode() * * Written by (.version is ignored): * - lzma_block_header_decode() always sets this to false */ lzma_bool ignore_check; lzma_bool reserved_bool2; lzma_bool reserved_bool3; lzma_bool reserved_bool4; lzma_bool reserved_bool5; lzma_bool reserved_bool6; lzma_bool reserved_bool7; lzma_bool reserved_bool8; } lzma_block; /** * \brief Decode the Block Header Size field * * To decode Block Header using lzma_block_header_decode(), the size of the * Block Header has to be known and stored into lzma_block.header_size. * The size can be calculated from the first byte of a Block using this macro. * Note that if the first byte is 0x00, it indicates beginning of Index; use * this macro only when the byte is not 0x00. * * There is no encoding macro, because Block Header encoder is enough for that. */ #define lzma_block_header_size_decode(b) (((uint32_t)(b) + 1) * 4) /** * \brief Calculate Block Header Size * * Calculate the minimum size needed for the Block Header field using the * settings specified in the lzma_block structure. Note that it is OK to * increase the calculated header_size value as long as it is a multiple of * four and doesn't exceed LZMA_BLOCK_HEADER_SIZE_MAX. Increasing header_size * just means that lzma_block_header_encode() will add Header Padding. * * \return - LZMA_OK: Size calculated successfully and stored to * block->header_size. * - LZMA_OPTIONS_ERROR: Unsupported version, filters or * filter options. * - LZMA_PROG_ERROR: Invalid values like compressed_size == 0. * * \note This doesn't check that all the options are valid i.e. this * may return LZMA_OK even if lzma_block_header_encode() or * lzma_block_encoder() would fail. If you want to validate the * filter chain, consider using lzma_memlimit_encoder() which as * a side-effect validates the filter chain. */ extern LZMA_API(lzma_ret) lzma_block_header_size(lzma_block *block) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Encode Block Header * * The caller must have calculated the size of the Block Header already with * lzma_block_header_size(). If a value larger than the one calculated by * lzma_block_header_size() is used, the Block Header will be padded to the * specified size. * * \param out Beginning of the output buffer. This must be * at least block->header_size bytes. * \param block Block options to be encoded. * * \return - LZMA_OK: Encoding was successful. block->header_size * bytes were written to output buffer. * - LZMA_OPTIONS_ERROR: Invalid or unsupported options. * - LZMA_PROG_ERROR: Invalid arguments, for example * block->header_size is invalid or block->filters is NULL. */ extern LZMA_API(lzma_ret) lzma_block_header_encode( const lzma_block *block, uint8_t *out) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Decode Block Header * * block->version should (usually) be set to the highest value supported * by the application. If the application sets block->version to a value * higher than supported by the current liblzma version, this function will * downgrade block->version to the highest value supported by it. Thus one * should check the value of block->version after calling this function if * block->version was set to a non-zero value and the application doesn't * otherwise know that the liblzma version being used is new enough to * support the specified block->version. * * The size of the Block Header must have already been decoded with * lzma_block_header_size_decode() macro and stored to block->header_size. * * The integrity check type from Stream Header must have been stored * to block->check. * * block->filters must have been allocated, but they don't need to be * initialized (possible existing filter options are not freed). * * \param block Destination for Block options. * \param allocator lzma_allocator for custom allocator functions. * Set to NULL to use malloc() (and also free() * if an error occurs). * \param in Beginning of the input buffer. This must be * at least block->header_size bytes. * * \return - LZMA_OK: Decoding was successful. block->header_size * bytes were read from the input buffer. * - LZMA_OPTIONS_ERROR: The Block Header specifies some * unsupported options such as unsupported filters. This can * happen also if block->version was set to a too low value * compared to what would be required to properly represent * the information stored in the Block Header. * - LZMA_DATA_ERROR: Block Header is corrupt, for example, * the CRC32 doesn't match. * - LZMA_PROG_ERROR: Invalid arguments, for example * block->header_size is invalid or block->filters is NULL. */ extern LZMA_API(lzma_ret) lzma_block_header_decode(lzma_block *block, const lzma_allocator *allocator, const uint8_t *in) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Validate and set Compressed Size according to Unpadded Size * * Block Header stores Compressed Size, but Index has Unpadded Size. If the * application has already parsed the Index and is now decoding Blocks, * it can calculate Compressed Size from Unpadded Size. This function does * exactly that with error checking: * * - Compressed Size calculated from Unpadded Size must be positive integer, * that is, Unpadded Size must be big enough that after Block Header and * Check fields there's still at least one byte for Compressed Size. * * - If Compressed Size was present in Block Header, the new value * calculated from Unpadded Size is compared against the value * from Block Header. * * \note This function must be called _after_ decoding the Block Header * field so that it can properly validate Compressed Size if it * was present in Block Header. * * \return - LZMA_OK: block->compressed_size was set successfully. * - LZMA_DATA_ERROR: unpadded_size is too small compared to * block->header_size and lzma_check_size(block->check). * - LZMA_PROG_ERROR: Some values are invalid. For example, * block->header_size must be a multiple of four and * between 8 and 1024 inclusive. */ extern LZMA_API(lzma_ret) lzma_block_compressed_size( lzma_block *block, lzma_vli unpadded_size) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Calculate Unpadded Size * * The Index field stores Unpadded Size and Uncompressed Size. The latter * can be taken directly from the lzma_block structure after coding a Block, * but Unpadded Size needs to be calculated from Block Header Size, * Compressed Size, and size of the Check field. This is where this function * is needed. * * \return Unpadded Size on success, or zero on error. */ extern LZMA_API(lzma_vli) lzma_block_unpadded_size(const lzma_block *block) lzma_nothrow lzma_attr_pure; /** * \brief Calculate the total encoded size of a Block * * This is equivalent to lzma_block_unpadded_size() except that the returned * value includes the size of the Block Padding field. * * \return On success, total encoded size of the Block. On error, * zero is returned. */ extern LZMA_API(lzma_vli) lzma_block_total_size(const lzma_block *block) lzma_nothrow lzma_attr_pure; /** * \brief Initialize .xz Block encoder * * Valid actions for lzma_code() are LZMA_RUN, LZMA_SYNC_FLUSH (only if the * filter chain supports it), and LZMA_FINISH. * * \return - LZMA_OK: All good, continue with lzma_code(). * - LZMA_MEM_ERROR * - LZMA_OPTIONS_ERROR * - LZMA_UNSUPPORTED_CHECK: block->check specifies a Check ID * that is not supported by this buid of liblzma. Initializing * the encoder failed. * - LZMA_PROG_ERROR */ extern LZMA_API(lzma_ret) lzma_block_encoder( lzma_stream *strm, lzma_block *block) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Initialize .xz Block decoder * * Valid actions for lzma_code() are LZMA_RUN and LZMA_FINISH. Using * LZMA_FINISH is not required. It is supported only for convenience. * * \return - LZMA_OK: All good, continue with lzma_code(). * - LZMA_UNSUPPORTED_CHECK: Initialization was successful, but * the given Check ID is not supported, thus Check will be * ignored. * - LZMA_PROG_ERROR * - LZMA_MEM_ERROR */ extern LZMA_API(lzma_ret) lzma_block_decoder( lzma_stream *strm, lzma_block *block) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Calculate maximum output size for single-call Block encoding * * This is equivalent to lzma_stream_buffer_bound() but for .xz Blocks. * See the documentation of lzma_stream_buffer_bound(). */ extern LZMA_API(size_t) lzma_block_buffer_bound(size_t uncompressed_size) lzma_nothrow; /** * \brief Single-call .xz Block encoder * * In contrast to the multi-call encoder initialized with * lzma_block_encoder(), this function encodes also the Block Header. This * is required to make it possible to write appropriate Block Header also * in case the data isn't compressible, and different filter chain has to be * used to encode the data in uncompressed form using uncompressed chunks * of the LZMA2 filter. * * When the data isn't compressible, header_size, compressed_size, and * uncompressed_size are set just like when the data was compressible, but * it is possible that header_size is too small to hold the filter chain * specified in block->filters, because that isn't necessarily the filter * chain that was actually used to encode the data. lzma_block_unpadded_size() * still works normally, because it doesn't read the filters array. * * \param block Block options: block->version, block->check, * and block->filters must have been initialized. * \param allocator lzma_allocator for custom allocator functions. * Set to NULL to use malloc() and free(). * \param in Beginning of the input buffer * \param in_size Size of the input buffer * \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: Not enough output buffer space. * - LZMA_UNSUPPORTED_CHECK * - LZMA_OPTIONS_ERROR * - LZMA_MEM_ERROR * - LZMA_DATA_ERROR * - LZMA_PROG_ERROR */ extern LZMA_API(lzma_ret) lzma_block_buffer_encode( lzma_block *block, const lzma_allocator *allocator, const uint8_t *in, size_t in_size, uint8_t *out, size_t *out_pos, size_t out_size) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Single-call uncompressed .xz Block encoder * * This is like lzma_block_buffer_encode() except this doesn't try to * compress the data and instead encodes the data using LZMA2 uncompressed * chunks. The required output buffer size can be determined with * lzma_block_buffer_bound(). * * Since the data won't be compressed, this function ignores block->filters. * This function doesn't take lzma_allocator because this function doesn't * allocate any memory from the heap. */ extern LZMA_API(lzma_ret) lzma_block_uncomp_encode(lzma_block *block, const uint8_t *in, size_t in_size, uint8_t *out, size_t *out_pos, size_t out_size) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Single-call .xz Block decoder * * This is single-call equivalent of lzma_block_decoder(), and requires that * the caller has already decoded Block Header and checked its memory usage. * * \param block Block options just like with lzma_block_decoder(). * \param allocator lzma_allocator for custom allocator functions. * Set to NULL to use malloc() and free(). * \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]. * \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: Decoding was successful. * - LZMA_OPTIONS_ERROR * - LZMA_DATA_ERROR * - LZMA_MEM_ERROR * - LZMA_BUF_ERROR: Output buffer was too small. * - LZMA_PROG_ERROR */ extern LZMA_API(lzma_ret) lzma_block_buffer_decode( lzma_block *block, const lzma_allocator *allocator, const uint8_t *in, size_t *in_pos, size_t in_size, uint8_t *out, size_t *out_pos, size_t out_size) lzma_nothrow;