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3d409c16ee
Best reviewed with: `git show --word-diff`. Signed-off-by: Andreas Schneider <asn@samba.org> Reviewed-by: Andrew Bartlett <abartlet@samba.org>
96 lines
2.7 KiB
C
96 lines
2.7 KiB
C
/*
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* Samba compression library - LGPLv3
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*
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* Copyright © Catalyst IT 2022
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*
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* ** NOTE! The following LGPL license applies to this file.
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* ** It does NOT imply that all of Samba is released under the LGPL
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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 3 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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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef HAVE_LZXPRESS_HUFFMAN_H
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#define HAVE_LZXPRESS_HUFFMAN_H
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struct huffman_node {
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struct huffman_node *left;
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struct huffman_node *right;
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uint32_t count;
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uint16_t symbol;
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int8_t depth;
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};
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/*
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* LZX_HUFF_COMP_HASH_BITS is how big to make the hash tables
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* (12 means 4096, etc).
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*
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* A larger number (up to 16) will be faster on long messages (fewer
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* collisions), but probably slower on short ones (more prep).
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*/
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#define LZX_HUFF_COMP_HASH_BITS 14
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/*
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* This struct just coalesces all the memory you need for LZ77 + Huffman
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* compression together in one bundle.
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*
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* There are a few different things you want, you usually want them all, so
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* this makes it easy to allocate them all at once.
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*/
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struct lzxhuff_compressor_mem {
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struct huffman_node leaf_nodes[512];
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struct huffman_node internal_nodes[512];
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uint16_t symbol_values[512];
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uint16_t intermediate[65536 + 6];
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uint16_t hash_table1[1 << LZX_HUFF_COMP_HASH_BITS];
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uint16_t hash_table2[1 << LZX_HUFF_COMP_HASH_BITS];
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};
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ssize_t lzxpress_huffman_compress(struct lzxhuff_compressor_mem *cmp,
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const uint8_t *input_bytes,
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size_t input_size,
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uint8_t *output,
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size_t available_size);
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ssize_t lzxpress_huffman_compress_talloc(TALLOC_CTX *mem_ctx,
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const uint8_t *input_bytes,
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size_t input_size,
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uint8_t **output);
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ssize_t lzxpress_huffman_decompress(const uint8_t *input,
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size_t input_size,
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uint8_t *output,
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size_t max_output_size);
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uint8_t *lzxpress_huffman_decompress_talloc(TALLOC_CTX *mem_ctx,
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const uint8_t *input_bytes,
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size_t input_size,
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size_t output_size);
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/*
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* lzxpress_huffman_max_compressed_size()
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*
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* Return the most bytes the compression can take, to allow
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* pre-allocation.
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*/
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size_t lzxpress_huffman_max_compressed_size(size_t input_size);
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#endif /* HAVE_LZXPRESS_HUFFMAN_H */
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