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author | Lasse Collin <lasse.collin@tukaani.org> | 2008-06-18 18:02:10 +0300 |
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committer | Lasse Collin <lasse.collin@tukaani.org> | 2008-06-18 18:02:10 +0300 |
commit | 7d17818cec8597f847b0a2537fde991bbc3d9e96 (patch) | |
tree | 9c41502e3eb96f103fe98e13456b382fbba7a292 /src/liblzma/api/lzma/index_hash.h | |
parent | Update the file format specification draft. The new one is (diff) | |
download | xz-7d17818cec8597f847b0a2537fde991bbc3d9e96.tar.xz |
Update the code to mostly match the new simpler file format
specification. Simplify things by removing most of the
support for known uncompressed size in most places.
There are some miscellaneous changes here and there too.
The API of liblzma has got many changes and still some
more will be done soon. While most of the code has been
updated, some things are not fixed (the command line tool
will choke with invalid filter chain, if nothing else).
Subblock filter is somewhat broken for now. It will be
updated once the encoded format of the Subblock filter
has been decided.
Diffstat (limited to 'src/liblzma/api/lzma/index_hash.h')
-rw-r--r-- | src/liblzma/api/lzma/index_hash.h | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/src/liblzma/api/lzma/index_hash.h b/src/liblzma/api/lzma/index_hash.h new file mode 100644 index 00000000..1edbbeaa --- /dev/null +++ b/src/liblzma/api/lzma/index_hash.h @@ -0,0 +1,94 @@ +/** + * \file lzma/index_hash.h + * \brief Validates Index by using a hash function + * + * Instead of constructing complete Index while decoding Blocks, Index hash + * calculates a hash of the Block sizes and Index, and then compares the + * hashes. This way memory usage is constant even with large number of + * Blocks and huge Index. + * + * \author Copyright (C) 2008 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 Opaque data type to hold the Index hash + */ +typedef struct lzma_index_hash_s lzma_index_hash; + + +/** + * \brief Allocate and initialize a new lzma_index_hash structure + * + * If index_hash is NULL, a new lzma_index_hash structure is allocated, + * initialized, and a pointer to it returned. If allocation fails, NULL + * is returned. + * + * If index_hash is non-NULL, it is reinitialized and the same pointer + * returned. In this case, return value cannot be NULL or a different + * pointer than the index_hash given as argument. + */ +extern lzma_index_hash *lzma_index_hash_init( + lzma_index_hash *index_hash, lzma_allocator *allocator); + + +/** + * \brief Deallocate the Index hash + */ +extern void lzma_index_hash_end( + lzma_index_hash *index_hash, lzma_allocator *allocator); + + +/** + * \brief Add a new Record to an Index hash + * + * \param index Pointer to a lzma_index_hash structure + * \param total_size Total Size of a Block + * \param uncompressed_size Uncompressed Size of a Block + * + * \return - LZMA_OK + * - LZMA_DATA_ERROR: Compressed or uncompressed size of the + * Stream or size of the Index field would grow too big. + * - LZMA_PROG_ERROR: Invalid arguments or this function is being + * used when lzma_index_hash_decode() has already been used. + */ +extern lzma_ret lzma_index_hash_append(lzma_index_hash *index_hash, + lzma_vli total_size, lzma_vli uncompressed_size); + + +/** + * \brief Decode the Index field + * + * \return - LZMA_OK: So far good, but more input is needed. + * - LZMA_STREAM_END: Index decoded successfully and it matches + * the Records given with lzma_index_hash_append(). + * - LZMA_DATA_ERROR: Index is corrupt or doesn't match the + * information given with lzma_index_hash_append(). + * - LZMA_PROG_ERROR + * + * \note Once decoding of the Index field has been started, no more + * Records can be added using lzma_index_hash_append(). + */ +extern lzma_ret lzma_index_hash_decode(lzma_index_hash *index_hash, + const uint8_t *in, size_t *in_pos, size_t in_size); + + +/** + * \brief Get the size of the Index field as bytes + * + * This is needed to verify the Index Size field from the Stream Footer. + */ +extern lzma_vli lzma_index_hash_size(const lzma_index_hash *index_hash); |