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hush/archival/libunarchive/decompress_unlzma.c

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/* vi: set sw=4 ts=4: */
/*
* Small lzma deflate implementation.
* Copyright (C) 2006 Aurelien Jacobs <aurel@gnuage.org>
*
* Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
* Copyright (C) 1999-2005 Igor Pavlov
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
#include "unarchive.h"
#ifdef CONFIG_FEATURE_LZMA_FAST
# define speed_inline ATTRIBUTE_ALWAYS_INLINE
#else
# define speed_inline
#endif
typedef struct {
int fd;
uint8_t *ptr;
uint8_t *buffer;
uint8_t *buffer_end;
int buffer_size;
uint32_t code;
uint32_t range;
uint32_t bound;
} rc_t;
#define RC_TOP_BITS 24
#define RC_MOVE_BITS 5
#define RC_MODEL_TOTAL_BITS 11
/* Called twice: once at startup and once in rc_normalize() */
static void rc_read(rc_t * rc)
{
rc->buffer_size = read(rc->fd, rc->buffer, rc->buffer_size);
if (rc->buffer_size <= 0)
bb_error_msg_and_die("unexpected EOF");
rc->ptr = rc->buffer;
rc->buffer_end = rc->buffer + rc->buffer_size;
}
/* Called once */
static void rc_init(rc_t * rc, int fd, int buffer_size)
{
int i;
rc->fd = fd;
rc->buffer = xmalloc(buffer_size);
rc->buffer_size = buffer_size;
rc->buffer_end = rc->buffer + rc->buffer_size;
rc->ptr = rc->buffer_end;
rc->code = 0;
rc->range = 0xFFFFFFFF;
for (i = 0; i < 5; i++) {
if (rc->ptr >= rc->buffer_end)
rc_read(rc);
rc->code = (rc->code << 8) | *rc->ptr++;
}
}
/* Called once. TODO: bb_maybe_free() */
static ATTRIBUTE_ALWAYS_INLINE void rc_free(rc_t * rc)
{
if (ENABLE_FEATURE_CLEAN_UP)
free(rc->buffer);
}
/* Called twice, but one callsite is in speed_inline'd rc_is_bit_0_helper() */
static void rc_do_normalize(rc_t * rc)
{
if (rc->ptr >= rc->buffer_end)
rc_read(rc);
rc->range <<= 8;
rc->code = (rc->code << 8) | *rc->ptr++;
}
static ATTRIBUTE_ALWAYS_INLINE void rc_normalize(rc_t * rc)
{
if (rc->range < (1 << RC_TOP_BITS)) {
rc_do_normalize(rc);
}
}
/* Called 9 times */
/* Why rc_is_bit_0_helper exists?
* Because we want to always expose (rc->code < rc->bound) to optimizer
*/
static speed_inline uint32_t rc_is_bit_0_helper(rc_t * rc, uint16_t * p)
{
rc_normalize(rc);
rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
return rc->bound;
}
static ATTRIBUTE_ALWAYS_INLINE int rc_is_bit_0(rc_t * rc, uint16_t * p)
{
uint32_t t = rc_is_bit_0_helper(rc, p);
return rc->code < t;
}
/* Called ~10 times, but very small, thus inlined */
static speed_inline void rc_update_bit_0(rc_t * rc, uint16_t * p)
{
rc->range = rc->bound;
*p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
}
static speed_inline void rc_update_bit_1(rc_t * rc, uint16_t * p)
{
rc->range -= rc->bound;
rc->code -= rc->bound;
*p -= *p >> RC_MOVE_BITS;
}
/* Called 4 times in unlzma loop */
static int rc_get_bit(rc_t * rc, uint16_t * p, int *symbol)
{
if (rc_is_bit_0(rc, p)) {
rc_update_bit_0(rc, p);
*symbol *= 2;
return 0;
} else {
rc_update_bit_1(rc, p);
*symbol = *symbol * 2 + 1;
return 1;
}
}
/* Called once */
static ATTRIBUTE_ALWAYS_INLINE int rc_direct_bit(rc_t * rc)
{
rc_normalize(rc);
rc->range >>= 1;
if (rc->code >= rc->range) {
rc->code -= rc->range;
return 1;
}
return 0;
}
/* Called twice */
static speed_inline void
rc_bit_tree_decode(rc_t * rc, uint16_t * p, int num_levels, int *symbol)
{
int i = num_levels;
*symbol = 1;
while (i--)
rc_get_bit(rc, p + *symbol, symbol);
*symbol -= 1 << num_levels;
}
typedef struct {
uint8_t pos;
uint32_t dict_size;
uint64_t dst_size;
} __attribute__ ((packed)) lzma_header_t;
#define LZMA_BASE_SIZE 1846
#define LZMA_LIT_SIZE 768
#define LZMA_NUM_POS_BITS_MAX 4
#define LZMA_LEN_NUM_LOW_BITS 3
#define LZMA_LEN_NUM_MID_BITS 3
#define LZMA_LEN_NUM_HIGH_BITS 8
#define LZMA_LEN_CHOICE 0
#define LZMA_LEN_CHOICE_2 (LZMA_LEN_CHOICE + 1)
#define LZMA_LEN_LOW (LZMA_LEN_CHOICE_2 + 1)
#define LZMA_LEN_MID (LZMA_LEN_LOW \
+ (1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_LOW_BITS)))
#define LZMA_LEN_HIGH (LZMA_LEN_MID \
+(1 << (LZMA_NUM_POS_BITS_MAX + LZMA_LEN_NUM_MID_BITS)))
#define LZMA_NUM_LEN_PROBS (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS))
#define LZMA_NUM_STATES 12
#define LZMA_NUM_LIT_STATES 7
#define LZMA_START_POS_MODEL_INDEX 4
#define LZMA_END_POS_MODEL_INDEX 14
#define LZMA_NUM_FULL_DISTANCES (1 << (LZMA_END_POS_MODEL_INDEX >> 1))
#define LZMA_NUM_POS_SLOT_BITS 6
#define LZMA_NUM_LEN_TO_POS_STATES 4
#define LZMA_NUM_ALIGN_BITS 4
#define LZMA_MATCH_MIN_LEN 2
#define LZMA_IS_MATCH 0
#define LZMA_IS_REP (LZMA_IS_MATCH + (LZMA_NUM_STATES <<LZMA_NUM_POS_BITS_MAX))
#define LZMA_IS_REP_G0 (LZMA_IS_REP + LZMA_NUM_STATES)
#define LZMA_IS_REP_G1 (LZMA_IS_REP_G0 + LZMA_NUM_STATES)
#define LZMA_IS_REP_G2 (LZMA_IS_REP_G1 + LZMA_NUM_STATES)
#define LZMA_IS_REP_0_LONG (LZMA_IS_REP_G2 + LZMA_NUM_STATES)
#define LZMA_POS_SLOT (LZMA_IS_REP_0_LONG \
+ (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
#define LZMA_SPEC_POS (LZMA_POS_SLOT \
+(LZMA_NUM_LEN_TO_POS_STATES << LZMA_NUM_POS_SLOT_BITS))
#define LZMA_ALIGN (LZMA_SPEC_POS \
+ LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX)
#define LZMA_LEN_CODER (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS))
#define LZMA_REP_LEN_CODER (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS)
#define LZMA_LITERAL (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS)
int unlzma(int src_fd, int dst_fd)
{
lzma_header_t header;
int lc, pb, lp;
uint32_t pos_state_mask;
uint32_t literal_pos_mask;
uint32_t pos;
uint16_t *p;
uint16_t *prob;
uint16_t *prob_lit;
int num_bits;
int num_probs;
rc_t rc;
int i, mi;
uint8_t *buffer;
uint8_t previous_byte = 0;
size_t buffer_pos = 0, global_pos = 0;
int len = 0;
int state = 0;
uint32_t rep0 = 1, rep1 = 1, rep2 = 1, rep3 = 1;
if (read(src_fd, &header, sizeof(header)) != sizeof(header))
bb_error_msg_and_die("can't read header");
if (header.pos >= (9 * 5 * 5))
bb_error_msg_and_die("bad header");
mi = header.pos / 9;
lc = header.pos % 9;
pb = mi / 5;
lp = mi % 5;
pos_state_mask = (1 << pb) - 1;
literal_pos_mask = (1 << lp) - 1;
header.dict_size = SWAP_LE32(header.dict_size);
header.dst_size = SWAP_LE64(header.dst_size);
if (header.dict_size == 0)
header.dict_size = 1;
buffer = xmalloc(MIN(header.dst_size, header.dict_size));
num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
p = xmalloc(num_probs * sizeof(*p));
num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
for (i = 0; i < num_probs; i++)
p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
rc_init(&rc, src_fd, 0x10000);
while (global_pos + buffer_pos < header.dst_size) {
int pos_state = (buffer_pos + global_pos) & pos_state_mask;
prob =
p + LZMA_IS_MATCH + (state << LZMA_NUM_POS_BITS_MAX) + pos_state;
if (rc_is_bit_0(&rc, prob)) {
mi = 1;
rc_update_bit_0(&rc, prob);
prob = (p + LZMA_LITERAL + (LZMA_LIT_SIZE
* ((((buffer_pos + global_pos) & literal_pos_mask) << lc)
+ (previous_byte >> (8 - lc)))));
if (state >= LZMA_NUM_LIT_STATES) {
int match_byte;
pos = buffer_pos - rep0;
while (pos >= header.dict_size)
pos += header.dict_size;
match_byte = buffer[pos];
do {
int bit;
match_byte <<= 1;
bit = match_byte & 0x100;
prob_lit = prob + 0x100 + bit + mi;
if (rc_get_bit(&rc, prob_lit, &mi)) {
if (!bit)
break;
} else {
if (bit)
break;
}
} while (mi < 0x100);
}
while (mi < 0x100) {
prob_lit = prob + mi;
rc_get_bit(&rc, prob_lit, &mi);
}
previous_byte = (uint8_t) mi;
buffer[buffer_pos++] = previous_byte;
if (buffer_pos == header.dict_size) {
buffer_pos = 0;
global_pos += header.dict_size;
write(dst_fd, buffer, header.dict_size);
}
if (state < 4)
state = 0;
else if (state < 10)
state -= 3;
else
state -= 6;
} else {
int offset;
uint16_t *prob_len;
rc_update_bit_1(&rc, prob);
prob = p + LZMA_IS_REP + state;
if (rc_is_bit_0(&rc, prob)) {
rc_update_bit_0(&rc, prob);
rep3 = rep2;
rep2 = rep1;
rep1 = rep0;
state = state < LZMA_NUM_LIT_STATES ? 0 : 3;
prob = p + LZMA_LEN_CODER;
} else {
rc_update_bit_1(&rc, prob);
prob = p + LZMA_IS_REP_G0 + state;
if (rc_is_bit_0(&rc, prob)) {
rc_update_bit_0(&rc, prob);
prob = (p + LZMA_IS_REP_0_LONG
+ (state << LZMA_NUM_POS_BITS_MAX) + pos_state);
if (rc_is_bit_0(&rc, prob)) {
rc_update_bit_0(&rc, prob);
state = state < LZMA_NUM_LIT_STATES ? 9 : 11;
pos = buffer_pos - rep0;
while (pos >= header.dict_size)
pos += header.dict_size;
previous_byte = buffer[pos];
buffer[buffer_pos++] = previous_byte;
if (buffer_pos == header.dict_size) {
buffer_pos = 0;
global_pos += header.dict_size;
write(dst_fd, buffer, header.dict_size);
}
continue;
} else {
rc_update_bit_1(&rc, prob);
}
} else {
uint32_t distance;
rc_update_bit_1(&rc, prob);
prob = p + LZMA_IS_REP_G1 + state;
if (rc_is_bit_0(&rc, prob)) {
rc_update_bit_0(&rc, prob);
distance = rep1;
} else {
rc_update_bit_1(&rc, prob);
prob = p + LZMA_IS_REP_G2 + state;
if (rc_is_bit_0(&rc, prob)) {
rc_update_bit_0(&rc, prob);
distance = rep2;
} else {
rc_update_bit_1(&rc, prob);
distance = rep3;
rep3 = rep2;
}
rep2 = rep1;
}
rep1 = rep0;
rep0 = distance;
}
state = state < LZMA_NUM_LIT_STATES ? 8 : 11;
prob = p + LZMA_REP_LEN_CODER;
}
prob_len = prob + LZMA_LEN_CHOICE;
if (rc_is_bit_0(&rc, prob_len)) {
rc_update_bit_0(&rc, prob_len);
prob_len = (prob + LZMA_LEN_LOW
+ (pos_state << LZMA_LEN_NUM_LOW_BITS));
offset = 0;
num_bits = LZMA_LEN_NUM_LOW_BITS;
} else {
rc_update_bit_1(&rc, prob_len);
prob_len = prob + LZMA_LEN_CHOICE_2;
if (rc_is_bit_0(&rc, prob_len)) {
rc_update_bit_0(&rc, prob_len);
prob_len = (prob + LZMA_LEN_MID
+ (pos_state << LZMA_LEN_NUM_MID_BITS));
offset = 1 << LZMA_LEN_NUM_LOW_BITS;
num_bits = LZMA_LEN_NUM_MID_BITS;
} else {
rc_update_bit_1(&rc, prob_len);
prob_len = prob + LZMA_LEN_HIGH;
offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
+ (1 << LZMA_LEN_NUM_MID_BITS));
num_bits = LZMA_LEN_NUM_HIGH_BITS;
}
}
rc_bit_tree_decode(&rc, prob_len, num_bits, &len);
len += offset;
if (state < 4) {
int pos_slot;
state += LZMA_NUM_LIT_STATES;
prob =
p + LZMA_POS_SLOT +
((len <
LZMA_NUM_LEN_TO_POS_STATES ? len :
LZMA_NUM_LEN_TO_POS_STATES - 1)
<< LZMA_NUM_POS_SLOT_BITS);
rc_bit_tree_decode(&rc, prob, LZMA_NUM_POS_SLOT_BITS,
&pos_slot);
if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
num_bits = (pos_slot >> 1) - 1;
rep0 = 2 | (pos_slot & 1);
if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
rep0 <<= num_bits;
prob = p + LZMA_SPEC_POS + rep0 - pos_slot - 1;
} else {
num_bits -= LZMA_NUM_ALIGN_BITS;
while (num_bits--)
rep0 = (rep0 << 1) | rc_direct_bit(&rc);
prob = p + LZMA_ALIGN;
rep0 <<= LZMA_NUM_ALIGN_BITS;
num_bits = LZMA_NUM_ALIGN_BITS;
}
i = 1;
mi = 1;
while (num_bits--) {
if (rc_get_bit(&rc, prob + mi, &mi))
rep0 |= i;
i <<= 1;
}
} else
rep0 = pos_slot;
if (++rep0 == 0)
break;
}
len += LZMA_MATCH_MIN_LEN;
do {
pos = buffer_pos - rep0;
while (pos >= header.dict_size)
pos += header.dict_size;
previous_byte = buffer[pos];
buffer[buffer_pos++] = previous_byte;
if (buffer_pos == header.dict_size) {
buffer_pos = 0;
global_pos += header.dict_size;
write(dst_fd, buffer, header.dict_size);
}
len--;
} while (len != 0 && buffer_pos < header.dst_size);
}
}
write(dst_fd, buffer, buffer_pos);
rc_free(&rc);
return 0;
}
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