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https://github.com/sheumann/hush.git
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348 lines
9.4 KiB
C
348 lines
9.4 KiB
C
/*
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* Small lzma deflate implementation.
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* Copyright (C) 2006 Aurelien Jacobs <aurel@gnuage.org>
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*
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* Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
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* Copyright (C) 1999-2005 Igor Pavlov
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*
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* This program 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 program 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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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stdint.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <byteswap.h>
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#include "libbb.h"
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#include "rangecoder.h"
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typedef struct {
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uint8_t pos;
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uint32_t dict_size;
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uint64_t dst_size;
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} __attribute__ ((packed)) lzma_header_t;
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#define LZMA_BASE_SIZE 1846
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#define LZMA_LIT_SIZE 768
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#define LZMA_NUM_POS_BITS_MAX 4
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#define LZMA_LEN_NUM_LOW_BITS 3
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#define LZMA_LEN_NUM_MID_BITS 3
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#define LZMA_LEN_NUM_HIGH_BITS 8
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#define LZMA_LEN_CHOICE 0
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#define LZMA_LEN_CHOICE_2 (LZMA_LEN_CHOICE + 1)
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#define LZMA_LEN_LOW (LZMA_LEN_CHOICE_2 + 1)
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#define LZMA_LEN_MID (LZMA_LEN_LOW \
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+ (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS)))
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#define LZMA_LEN_HIGH (LZMA_LEN_MID \
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+(1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS)))
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#define LZMA_NUM_LEN_PROBS (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS))
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#define LZMA_NUM_STATES 12
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#define LZMA_NUM_LIT_STATES 7
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#define LZMA_START_POS_MODEL_INDEX 4
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#define LZMA_END_POS_MODEL_INDEX 14
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#define LZMA_NUM_FULL_DISTANCES (1 << (LZMA_END_POS_MODEL_INDEX >> 1))
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#define LZMA_NUM_POS_SLOT_BITS 6
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#define LZMA_NUM_LEN_TO_POS_STATES 4
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#define LZMA_NUM_ALIGN_BITS 4
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#define LZMA_MATCH_MIN_LEN 2
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#define LZMA_IS_MATCH 0
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#define LZMA_IS_REP (LZMA_IS_MATCH + (LZMA_NUM_STATES <<LZMA_NUM_POS_BITS_MAX))
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#define LZMA_IS_REP_G0 (LZMA_IS_REP + LZMA_NUM_STATES)
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#define LZMA_IS_REP_G1 (LZMA_IS_REP_G0 + LZMA_NUM_STATES)
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#define LZMA_IS_REP_G2 (LZMA_IS_REP_G1 + LZMA_NUM_STATES)
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#define LZMA_IS_REP_0_LONG (LZMA_IS_REP_G2 + LZMA_NUM_STATES)
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#define LZMA_POS_SLOT (LZMA_IS_REP_0_LONG \
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+ (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
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#define LZMA_SPEC_POS (LZMA_POS_SLOT \
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+(LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS))
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#define LZMA_ALIGN (LZMA_SPEC_POS \
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+ LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX)
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#define LZMA_LEN_CODER (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS))
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#define LZMA_REP_LEN_CODER (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS)
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#define LZMA_LITERAL (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS)
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int unlzma(int src_fd, int dst_fd)
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{
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lzma_header_t header;
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int lc, pb, lp;
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uint32_t pos_state_mask;
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uint32_t literal_pos_mask;
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uint32_t pos;
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uint16_t *p;
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uint16_t *prob;
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uint16_t *prob_lit;
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int num_bits;
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int num_probs;
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rc_t rc;
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int i, mi;
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uint8_t *buffer;
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uint8_t previous_byte = 0;
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size_t buffer_pos = 0, global_pos = 0;
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int len = 0;
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int state = 0;
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uint32_t rep0 = 1, rep1 = 1, rep2 = 1, rep3 = 1;
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if (read(src_fd, &header, sizeof(header)) != sizeof(header))
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bb_error_msg_and_die("can't read header");
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if (header.pos >= (9 * 5 * 5))
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bb_error_msg_and_die("bad header");
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mi = header.pos / 9;
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lc = header.pos % 9;
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pb = mi / 5;
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lp = mi % 5;
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pos_state_mask = (1 << pb) - 1;
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literal_pos_mask = (1 << lp) - 1;
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#if __BYTE_ORDER == __BIG_ENDIAN
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header.dict_size = bswap_32(header.dict_size);
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header.dst_size = bswap_64(header.dst_size);
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#endif /* __BYTE_ORDER */
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if (header.dict_size == 0)
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header.dict_size = 1;
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buffer = xmalloc(MIN(header.dst_size, header.dict_size));
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num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
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p = xmalloc(num_probs * sizeof(*p));
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num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
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for (i = 0; i < num_probs; i++)
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p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
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rc_init(&rc, src_fd, 0x10000);
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while (global_pos + buffer_pos < header.dst_size) {
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int pos_state = (buffer_pos + global_pos) & pos_state_mask;
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prob =
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p + LZMA_IS_MATCH + (state << LZMA_NUM_POS_BITS_MAX) + pos_state;
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if (rc_is_bit_0(&rc, prob)) {
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mi = 1;
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rc_update_bit_0(&rc, prob);
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prob = (p + LZMA_LITERAL + (LZMA_LIT_SIZE
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* ((((buffer_pos + global_pos) & literal_pos_mask) << lc)
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+ (previous_byte >> (8 - lc)))));
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if (state >= LZMA_NUM_LIT_STATES) {
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int match_byte;
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pos = buffer_pos - rep0;
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while (pos >= header.dict_size)
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pos += header.dict_size;
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match_byte = buffer[pos];
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do {
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int bit;
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match_byte <<= 1;
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bit = match_byte & 0x100;
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prob_lit = prob + 0x100 + bit + mi;
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if (rc_get_bit(&rc, prob_lit, &mi)) {
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if (!bit)
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break;
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} else {
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if (bit)
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break;
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}
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} while (mi < 0x100);
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}
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while (mi < 0x100) {
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prob_lit = prob + mi;
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rc_get_bit(&rc, prob_lit, &mi);
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}
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previous_byte = (uint8_t) mi;
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buffer[buffer_pos++] = previous_byte;
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if (buffer_pos == header.dict_size) {
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buffer_pos = 0;
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global_pos += header.dict_size;
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write(dst_fd, buffer, header.dict_size);
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}
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if (state < 4)
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state = 0;
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else if (state < 10)
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state -= 3;
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else
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state -= 6;
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} else {
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int offset;
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uint16_t *prob_len;
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rc_update_bit_1(&rc, prob);
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prob = p + LZMA_IS_REP + state;
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if (rc_is_bit_0(&rc, prob)) {
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rc_update_bit_0(&rc, prob);
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rep3 = rep2;
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rep2 = rep1;
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rep1 = rep0;
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state = state < LZMA_NUM_LIT_STATES ? 0 : 3;
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prob = p + LZMA_LEN_CODER;
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} else {
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rc_update_bit_1(&rc, prob);
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prob = p + LZMA_IS_REP_G0 + state;
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if (rc_is_bit_0(&rc, prob)) {
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rc_update_bit_0(&rc, prob);
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prob = (p + LZMA_IS_REP_0_LONG
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+ (state << LZMA_NUM_POS_BITS_MAX) + pos_state);
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if (rc_is_bit_0(&rc, prob)) {
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rc_update_bit_0(&rc, prob);
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state = state < LZMA_NUM_LIT_STATES ? 9 : 11;
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pos = buffer_pos - rep0;
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while (pos >= header.dict_size)
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pos += header.dict_size;
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previous_byte = buffer[pos];
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buffer[buffer_pos++] = previous_byte;
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if (buffer_pos == header.dict_size) {
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buffer_pos = 0;
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global_pos += header.dict_size;
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write(dst_fd, buffer, header.dict_size);
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}
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continue;
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} else {
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rc_update_bit_1(&rc, prob);
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}
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} else {
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uint32_t distance;
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rc_update_bit_1(&rc, prob);
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prob = p + LZMA_IS_REP_G1 + state;
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if (rc_is_bit_0(&rc, prob)) {
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rc_update_bit_0(&rc, prob);
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distance = rep1;
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} else {
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rc_update_bit_1(&rc, prob);
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prob = p + LZMA_IS_REP_G2 + state;
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if (rc_is_bit_0(&rc, prob)) {
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rc_update_bit_0(&rc, prob);
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distance = rep2;
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} else {
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rc_update_bit_1(&rc, prob);
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distance = rep3;
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rep3 = rep2;
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}
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rep2 = rep1;
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}
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rep1 = rep0;
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rep0 = distance;
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}
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state = state < LZMA_NUM_LIT_STATES ? 8 : 11;
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prob = p + LZMA_REP_LEN_CODER;
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}
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prob_len = prob + LZMA_LEN_CHOICE;
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if (rc_is_bit_0(&rc, prob_len)) {
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rc_update_bit_0(&rc, prob_len);
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prob_len = (prob + LZMA_LEN_LOW
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+ (pos_state << LZMA_LEN_NUM_LOW_BITS));
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offset = 0;
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num_bits = LZMA_LEN_NUM_LOW_BITS;
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} else {
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rc_update_bit_1(&rc, prob_len);
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prob_len = prob + LZMA_LEN_CHOICE_2;
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if (rc_is_bit_0(&rc, prob_len)) {
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rc_update_bit_0(&rc, prob_len);
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prob_len = (prob + LZMA_LEN_MID
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+ (pos_state << LZMA_LEN_NUM_MID_BITS));
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offset = 1 << LZMA_LEN_NUM_LOW_BITS;
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num_bits = LZMA_LEN_NUM_MID_BITS;
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} else {
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rc_update_bit_1(&rc, prob_len);
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prob_len = prob + LZMA_LEN_HIGH;
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offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
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+ (1 << LZMA_LEN_NUM_MID_BITS));
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num_bits = LZMA_LEN_NUM_HIGH_BITS;
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}
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}
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rc_bit_tree_decode(&rc, prob_len, num_bits, &len);
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len += offset;
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if (state < 4) {
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int pos_slot;
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state += LZMA_NUM_LIT_STATES;
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prob =
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p + LZMA_POS_SLOT +
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((len <
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LZMA_NUM_LEN_TO_POS_STATES ? len :
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LZMA_NUM_LEN_TO_POS_STATES - 1)
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<< LZMA_NUM_POS_SLOT_BITS);
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rc_bit_tree_decode(&rc, prob, LZMA_NUM_POS_SLOT_BITS,
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&pos_slot);
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if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
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num_bits = (pos_slot >> 1) - 1;
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rep0 = 2 | (pos_slot & 1);
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if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
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rep0 <<= num_bits;
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prob = p + LZMA_SPEC_POS + rep0 - pos_slot - 1;
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} else {
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num_bits -= LZMA_NUM_ALIGN_BITS;
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while (num_bits--)
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rep0 = (rep0 << 1) | rc_direct_bit(&rc);
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prob = p + LZMA_ALIGN;
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rep0 <<= LZMA_NUM_ALIGN_BITS;
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num_bits = LZMA_NUM_ALIGN_BITS;
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}
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i = 1;
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mi = 1;
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while (num_bits--) {
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if (rc_get_bit(&rc, prob + mi, &mi))
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rep0 |= i;
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i <<= 1;
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}
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} else
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rep0 = pos_slot;
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if (++rep0 == 0)
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break;
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}
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len += LZMA_MATCH_MIN_LEN;
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do {
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pos = buffer_pos - rep0;
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while (pos >= header.dict_size)
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pos += header.dict_size;
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previous_byte = buffer[pos];
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buffer[buffer_pos++] = previous_byte;
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if (buffer_pos == header.dict_size) {
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buffer_pos = 0;
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global_pos += header.dict_size;
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write(dst_fd, buffer, header.dict_size);
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}
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len--;
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} while (len != 0 && buffer_pos < header.dst_size);
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}
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}
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write(dst_fd, buffer, buffer_pos);
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rc_free(&rc);
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return 0;
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}
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/* vi:set ts=4: */
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