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///////////////////////////////////////////////////////////////////////////////
//
/// \file raw_common.c
/// \brief Stuff shared between raw encoder and raw 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 "raw_common.h"
static lzma_ret
validate_options(const lzma_options_filter *options, size_t *count)
{
if (options == NULL)
return LZMA_PROG_ERROR;
// Number of non-last filters that may change the size of the data
// significantly (that is, more than 1-2 % or so).
size_t change = 0;
// True if the last filter in the given chain is actually usable as
// the last filter. Only filters that support embedding End of Payload
// Marker can be used as the last filter in the chain.
bool last_ok = false;
size_t i;
for (i = 0; options[i].id != LZMA_VLI_VALUE_UNKNOWN; ++i) {
switch (options[i].id) {
// Not #ifdeffing these for simplicity.
case LZMA_FILTER_X86:
case LZMA_FILTER_POWERPC:
case LZMA_FILTER_IA64:
case LZMA_FILTER_ARM:
case LZMA_FILTER_ARMTHUMB:
case LZMA_FILTER_SPARC:
case LZMA_FILTER_DELTA:
// These don't change the size of the data and cannot
// be used as the last filter in the chain.
last_ok = false;
break;
#ifdef HAVE_FILTER_SUBBLOCK
case LZMA_FILTER_SUBBLOCK:
last_ok = true;
++change;
break;
#endif
#ifdef HAVE_FILTER_LZMA
case LZMA_FILTER_LZMA:
last_ok = true;
break;
#endif
default:
return LZMA_HEADER_ERROR;
}
}
// There must be 1-4 filters and the last filter must be usable as
// the last filter in the chain.
if (i == 0 || i > 4 || !last_ok)
return LZMA_HEADER_ERROR;
// At maximum of two non-last filters are allowed to change the
// size of the data.
if (change > 2)
return LZMA_HEADER_ERROR;
*count = i;
return LZMA_OK;
}
extern lzma_ret
lzma_raw_coder_init(lzma_next_coder *next, lzma_allocator *allocator,
const lzma_options_filter *options,
lzma_init_function (*get_function)(lzma_vli id),
bool is_encoder)
{
// Do some basic validation and get the number of filters.
size_t count;
return_if_error(validate_options(options, &count));
// Set the filter functions and copy the options pointer.
lzma_filter_info filters[count + 1];
if (is_encoder) {
for (size_t i = 0; i < count; ++i) {
// The order of the filters is reversed in the
// encoder. It allows more efficient handling
// of the uncompressed data.
const size_t j = count - i - 1;
filters[j].init = get_function(options[i].id);
if (filters[j].init == NULL)
return LZMA_HEADER_ERROR;
filters[j].options = options[i].options;
}
} else {
for (size_t i = 0; i < count; ++i) {
filters[i].init = get_function(options[i].id);
if (filters[i].init == NULL)
return LZMA_HEADER_ERROR;
filters[i].options = options[i].options;
}
}
// Terminate the array.
filters[count].init = NULL;
// Initialize the filters.
return lzma_next_filter_init(next, allocator, filters);
}
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