2012-06-21 14:57:05 +00:00
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/*
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* rabin_polynomial_constants.h
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*
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* Created by Joel Lawrence Tucci on 09-May-2011.
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*
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* Copyright (c) 2011 Joel Lawrence Tucci
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* Neither the name of the project's author nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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2012-06-21 15:10:43 +00:00
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/*
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* This file is a part of Pcompress, a chunked parallel multi-
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* algorithm lossless compression and decompression program.
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*
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* Copyright (C) 2012 Moinak Ghosh. All rights reserved.
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* Use is subject to license terms.
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*
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* This program 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 program 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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* moinakg@belenix.org, http://moinakg.wordpress.com/
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*
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*/
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2012-06-29 12:53:55 +00:00
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#ifndef _RABIN_POLY_H_
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#define _RABIN_POLY_H_
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#include "utils.h"
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2012-06-21 14:57:05 +00:00
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//List of constants, mostly constraints and defaults for various parameters
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//to the Rabin Fingerprinting algorithm
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2012-06-29 12:53:55 +00:00
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#define RAB_POLYNOMIAL_CONST 2
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2012-06-21 14:57:05 +00:00
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// 1 << RAB_POLYNOMIAL_AVG_BLOCK_SHIFT = Average Rabin Chunk Size
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// So we are always looking at power of 2 chunk sizes to avoid doing a modulus
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//
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2012-06-29 12:53:55 +00:00
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// A value of 12 below gives avg block size of 4096 bytes
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//
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#define RAB_POLYNOMIAL_AVG_BLOCK_SHIFT 12
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#define RAB_POLYNOMIAL_AVG_BLOCK_SIZE (1 << RAB_POLYNOMIAL_AVG_BLOCK_SHIFT)
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#define RAB_POLYNOMIAL_AVG_BLOCK_MASK (RAB_POLYNOMIAL_AVG_BLOCK_SIZE - 1)
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#define RAB_POLYNOMIAL_MIN_BLOCK_SIZE (4096)
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#define RAB_POLYNOMIAL_MAX_BLOCK_SIZE (128 * 1024)
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#define RAB_POLYNOMIAL_WIN_SIZE 32
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#define RAB_POLYNOMIAL_MIN_WIN_SIZE 17
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#define RAB_POLYNOMIAL_MAX_WIN_SIZE 63
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typedef struct {
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ssize_t offset;
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uint64_t checksum;
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unsigned int index;
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unsigned int length;
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} rabin_blockentry_t;
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// An entry in the Rabin block array in the chunk.
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// It is either a length value <= RAB_POLYNOMIAL_MAX_BLOCK_SIZE or
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// if value > RAB_POLYNOMIAL_MAX_BLOCK_SIZE then
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// value - RAB_POLYNOMIAL_MAX_BLOCK_SIZE is index of block with which
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// this block is a duplicate.
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// Offset can be dynamically calculated.
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//
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#define RABIN_ENTRY_SIZE (sizeof (unsigned int))
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// Header for a chunk deduped using Rabin
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// Number of rabin blocks, size of original chunk
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2012-06-21 14:57:05 +00:00
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//
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2012-06-29 12:53:55 +00:00
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#define RABIN_HDR_SIZE (sizeof (unsigned int) + sizeof (ssize_t))
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2012-06-21 14:57:05 +00:00
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typedef struct {
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unsigned char *current_window_data;
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2012-06-29 12:53:55 +00:00
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rabin_blockentry_t *blocks;
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unsigned char *cbuf;
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unsigned char *buf;
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2012-06-21 14:57:05 +00:00
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int window_pos;
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uint64_t cur_roll_checksum;
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2012-06-29 12:53:55 +00:00
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uint64_t cur_checksum;
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uint64_t block_checksum;
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int dedup;
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int valid;
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2012-06-21 14:57:05 +00:00
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} rabin_context_t;
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2012-06-29 12:53:55 +00:00
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extern rabin_context_t *create_rabin_context(uint64_t chunksize);
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2012-06-21 14:57:05 +00:00
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extern void destroy_rabin_context(rabin_context_t *ctx);
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2012-06-29 12:53:55 +00:00
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extern void rabin_dedup(rabin_context_t *ctx, unsigned char *buf,
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ssize_t *size, ssize_t offset);
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extern void rabin_inverse_dedup(rabin_context_t *ctx, uchar_t *buf, ssize_t *size);
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extern void reset_rabin_context(rabin_context_t *ctx);
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2012-06-21 14:57:05 +00:00
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2012-06-29 12:53:55 +00:00
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#endif /* _RABIN_POLY_H_ */
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