mirror of https://git.tukaani.org/xz.git
99 lines
3.5 KiB
C
99 lines
3.5 KiB
C
/**
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* \file lzma/index_hash.h
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* \brief Validates Index by using a hash function
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*
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* Instead of constructing complete Index while decoding Blocks, Index hash
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* calculates a hash of the Block sizes and Index, and then compares the
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* hashes. This way memory usage is constant even with large number of
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* Blocks and huge Index.
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*
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* \author Copyright (C) 2008 Lasse Collin
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*/
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#ifndef LZMA_H_INTERNAL
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# error Never include this file directly. Use <lzma.h> instead.
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#endif
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/**
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* \brief Opaque data type to hold the Index hash
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*/
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typedef struct lzma_index_hash_s lzma_index_hash;
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/**
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* \brief Allocate and initialize a new lzma_index_hash structure
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*
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* If index_hash is NULL, a new lzma_index_hash structure is allocated,
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* initialized, and a pointer to it returned. If allocation fails, NULL
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* is returned.
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*
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* If index_hash is non-NULL, it is reinitialized and the same pointer
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* returned. In this case, return value cannot be NULL or a different
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* pointer than the index_hash given as argument.
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*/
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extern lzma_index_hash *lzma_index_hash_init(
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lzma_index_hash *index_hash, lzma_allocator *allocator)
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lzma_attr_warn_unused_result;
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/**
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* \brief Deallocate the Index hash
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*/
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extern void lzma_index_hash_end(
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lzma_index_hash *index_hash, lzma_allocator *allocator);
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/**
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* \brief Add a new Record to an Index hash
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*
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* \param index Pointer to a lzma_index_hash structure
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* \param total_size Total Size of a Block
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* \param uncompressed_size Uncompressed Size of a Block
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*
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* \return - LZMA_OK
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* - LZMA_DATA_ERROR: Compressed or uncompressed size of the
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* Stream or size of the Index field would grow too big.
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* - LZMA_PROG_ERROR: Invalid arguments or this function is being
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* used when lzma_index_hash_decode() has already been used.
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*/
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extern lzma_ret lzma_index_hash_append(lzma_index_hash *index_hash,
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lzma_vli total_size, lzma_vli uncompressed_size)
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lzma_attr_warn_unused_result;
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/**
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* \brief Decode the Index field
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*
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* \return - LZMA_OK: So far good, but more input is needed.
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* - LZMA_STREAM_END: Index decoded successfully and it matches
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* the Records given with lzma_index_hash_append().
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* - LZMA_DATA_ERROR: Index is corrupt or doesn't match the
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* information given with lzma_index_hash_append().
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* - LZMA_PROG_ERROR
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*
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* \note Once decoding of the Index field has been started, no more
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* Records can be added using lzma_index_hash_append().
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*/
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extern lzma_ret lzma_index_hash_decode(lzma_index_hash *index_hash,
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const uint8_t *in, size_t *in_pos, size_t in_size)
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lzma_attr_warn_unused_result;
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/**
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* \brief Get the size of the Index field as bytes
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*
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* This is needed to verify the Index Size field from the Stream Footer.
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*/
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extern lzma_vli lzma_index_hash_size(const lzma_index_hash *index_hash)
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lzma_attr_pure;
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