mirror of
https://git.tukaani.org/xz.git
synced 2024-04-04 12:36:23 +02:00
74 lines
2.3 KiB
C
74 lines
2.3 KiB
C
///////////////////////////////////////////////////////////////////////////////
|
|
//
|
|
/// \file lzma_literal.c
|
|
/// \brief Literal Coder
|
|
//
|
|
// Copyright (C) 1999-2006 Igor Pavlov
|
|
// 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 "lzma_literal.h"
|
|
|
|
|
|
extern lzma_ret
|
|
lzma_literal_init(lzma_literal_coder **coder, lzma_allocator *allocator,
|
|
uint32_t literal_context_bits, uint32_t literal_pos_bits)
|
|
{
|
|
// Verify that arguments are sane.
|
|
if (literal_context_bits > LZMA_LITERAL_CONTEXT_BITS_MAX
|
|
|| literal_pos_bits > LZMA_LITERAL_POS_BITS_MAX)
|
|
return LZMA_HEADER_ERROR;
|
|
|
|
// Calculate the number of states the literal coder must store.
|
|
const uint32_t states = literal_states(
|
|
literal_pos_bits, literal_context_bits);
|
|
|
|
// Allocate a new literal coder, if needed.
|
|
if (*coder == NULL || (**coder).literal_context_bits
|
|
!= literal_context_bits
|
|
|| (**coder).literal_pos_bits != literal_pos_bits) {
|
|
// Free the old coder, if any.
|
|
lzma_free(*coder, allocator);
|
|
|
|
// Allocate a new one.
|
|
*coder = lzma_alloc(sizeof(lzma_literal_coder)
|
|
+ states * LIT_SIZE * sizeof(probability),
|
|
allocator);
|
|
if (*coder == NULL)
|
|
return LZMA_MEM_ERROR;
|
|
|
|
// Store the new settings.
|
|
(**coder).literal_context_bits = literal_context_bits;
|
|
(**coder).literal_pos_bits = literal_pos_bits;
|
|
|
|
// Calculate also the literal_pos_mask. It's not changed
|
|
// anywhere else than here.
|
|
(**coder).literal_pos_mask = (1 << literal_pos_bits) - 1;
|
|
}
|
|
|
|
// Reset the literal coder.
|
|
for (uint32_t i = 0; i < states; ++i)
|
|
for (uint32_t j = 0; j < LIT_SIZE; ++j)
|
|
bit_reset((**coder).coders[i][j]);
|
|
|
|
return LZMA_OK;
|
|
}
|
|
|
|
|
|
extern void
|
|
lzma_literal_end(lzma_literal_coder **coder, lzma_allocator *allocator)
|
|
{
|
|
lzma_free(*coder, allocator);
|
|
*coder = NULL;
|
|
}
|