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67 lines
2.1 KiB
C
67 lines
2.1 KiB
C
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///////////////////////////////////////////////////////////////////////////////
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//
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/// \file delta_common.c
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/// \brief Common stuff for Delta encoder and decoder
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//
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// Copyright (C) 2007 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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///////////////////////////////////////////////////////////////////////////////
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#include "delta_common.h"
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static void
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delta_coder_end(lzma_coder *coder, lzma_allocator *allocator)
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{
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lzma_next_coder_end(&coder->next, allocator);
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lzma_free(coder, allocator);
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return;
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}
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extern lzma_ret
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lzma_delta_coder_init(lzma_next_coder *next, lzma_allocator *allocator,
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const lzma_filter_info *filters, lzma_code_function code)
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{
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// Allocate memory for the decoder if needed.
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if (next->coder == NULL) {
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next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
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if (next->coder == NULL)
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return LZMA_MEM_ERROR;
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// End function is the same for encoder and decoder.
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next->end = &delta_coder_end;
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next->coder->next = LZMA_NEXT_CODER_INIT;
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}
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// Coding function is different for encoder and decoder.
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next->code = code;
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// Set the delta distance.
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if (filters[0].options == NULL)
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return LZMA_PROG_ERROR;
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next->coder->distance = ((lzma_options_delta *)(filters[0].options))
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->distance;
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if (next->coder->distance < LZMA_DELTA_DISTANCE_MIN
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|| next->coder->distance > LZMA_DELTA_DISTANCE_MAX)
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return LZMA_HEADER_ERROR;
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// Initialize the rest of the variables.
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next->coder->pos = 0;
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memzero(next->coder->history, LZMA_DELTA_DISTANCE_MAX);
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// Initialize the next decoder in the chain, if any.
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return lzma_next_filter_init(&next->coder->next,
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allocator, filters + 1);
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}
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