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