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///////////////////////////////////////////////////////////////////////////////
//
/// \file copy_coder.c
/// \brief The Copy filter 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 "copy_coder.h"
struct lzma_coder_s {
lzma_next_coder next;
lzma_vli uncompressed_size;
bool is_encoder;
};
static lzma_ret
copy_code(lzma_coder *coder, lzma_allocator *allocator,
const uint8_t *restrict in, size_t *restrict in_pos,
size_t in_size, uint8_t *restrict out,
size_t *restrict out_pos, size_t out_size, lzma_action action)
{
// If we aren't the last filter in the chain, the Copy filter
// is totally useless. Note that it is job of the next coder to
// take care of Uncompressed Size, so we don't need to update our
// coder->uncompressed_size at all.
if (coder->next.code != NULL)
return coder->next.code(coder->next.coder, allocator,
in, in_pos, in_size, out, out_pos, out_size,
action);
// If we get here, we are the last filter in the chain.
const size_t in_avail = in_size - *in_pos;
if (coder->is_encoder) {
// Check that we don't have too much input.
if ((lzma_vli)(in_avail) > coder->uncompressed_size)
return LZMA_DATA_ERROR;
// Check that once LZMA_FINISH has been given, the
// amount of input matches uncompressed_size if it
// is known.
if (action == LZMA_FINISH && coder->uncompressed_size
!= LZMA_VLI_VALUE_UNKNOWN
&& coder->uncompressed_size
!= (lzma_vli)(in_avail))
return LZMA_DATA_ERROR;
} else {
// Limit in_size so that we don't copy too much.
if ((lzma_vli)(in_avail) > coder->uncompressed_size)
in_size = *in_pos + (size_t)(coder->uncompressed_size);
}
// Store the old input position, which is needed to update
// coder->uncompressed_size.
const size_t in_start = *in_pos;
// We are the last coder in the chain.
// Just copy as much data as possible.
bufcpy(in, in_pos, in_size, out, out_pos, out_size);
// Update uncompressed_size if it is known.
if (coder->uncompressed_size != LZMA_VLI_VALUE_UNKNOWN)
coder->uncompressed_size -= *in_pos - in_start;
// action can be LZMA_FINISH only in the encoder.
if ((action == LZMA_FINISH && *in_pos == in_size)
|| coder->uncompressed_size == 0)
return LZMA_STREAM_END;
return LZMA_OK;
}
static void
copy_coder_end(lzma_coder *coder, lzma_allocator *allocator)
{
lzma_next_coder_end(&coder->next, allocator);
lzma_free(coder, allocator);
return;
}
static lzma_ret
copy_coder_init(lzma_next_coder *next, lzma_allocator *allocator,
const lzma_filter_info *filters, bool is_encoder)
{
// 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;
next->code = ©_code;
next->end = ©_coder_end;
next->coder->next = LZMA_NEXT_CODER_INIT;
}
// Copy Uncompressed Size which is used to limit the output size.
next->coder->uncompressed_size = filters[0].uncompressed_size;
// The coder acts slightly differently as encoder and decoder.
next->coder->is_encoder = is_encoder;
// Initialize the next decoder in the chain, if any.
return lzma_next_filter_init(
&next->coder->next, allocator, filters + 1);
}
#ifdef HAVE_ENCODER
extern lzma_ret
lzma_copy_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
const lzma_filter_info *filters)
{
lzma_next_coder_init(copy_coder_init, next, allocator, filters, true);
}
#endif
#ifdef HAVE_DECODER
extern lzma_ret
lzma_copy_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
const lzma_filter_info *filters)
{
lzma_next_coder_init(copy_coder_init, next, allocator, filters, false);
}
#endif
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