/**
* \file lzma/block.h
* \brief .xz Block handling
*
* \author Copyright (C) 1999-2006 Igor Pavlov
* \author Copyright (C) 2007 Lasse Collin
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
#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 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()
*
* Written by:
* - lzma_block_header_size()
*/
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_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()
*
* Written by:
* - lzma_block_header_decode()
* - lzma_block_compressed_size()
* - lzma_block_encoder()
* - lzma_block_decoder()
*/
lzma_vli compressed_size;
/**
* \brief Uncompressed Size in bytes
*
* This is handled very similarly to compressed_size above.
*
* Unlike compressed_size, uncompressed_size is needed by fewer
* functions. 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()
*
* Written by:
* - lzma_block_header_decode()
* - lzma_block_encoder()
* - lzma_block_decoder()
*/
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()
*
* 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;
} 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 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_ret lzma_block_header_size(lzma_block *block)
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 larger value 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_ret lzma_block_header_encode(const lzma_block *block, uint8_t *out)
lzma_attr_warn_unused_result;
/**
* \brief Decode Block Header
*
* The size of the Block Header must have already been decoded with
* lzma_block_header_size_decode() macro and stored to block->header_size.
* block->filters must have been allocated, but not necessarily initialized.
* Possible existing filter options are _not_ freed.
*
* \param block Destination for block options with header_size
* properly initialized.
* \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.
* - 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_ret lzma_block_header_decode(lzma_block *block,
lzma_allocator *allocator, const uint8_t *in)
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_ret lzma_block_compressed_size(
lzma_block *block, lzma_vli unpadded_size)
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_vli lzma_block_unpadded_size(const lzma_block *block)
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_vli lzma_block_total_size(const lzma_block *block)
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 specfies a Check ID
* that is not supported by this buid of liblzma. Initializing
* the encoder failed.
* - LZMA_PROG_ERROR
*/
extern lzma_ret lzma_block_encoder(lzma_stream *strm, lzma_block *block)
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_ret lzma_block_decoder(lzma_stream *strm, lzma_block *block)
lzma_attr_warn_unused_result;
