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Major changes to LZ encoder, LZMA encoder, and range encoder.

These changes implement support for LZMA_SYNC_FLUSH in LZMA
encoder, and move the temporary buffer needed by range encoder
from lzma_range_encoder structure to lzma_lz_encoder.
This commit is contained in:
Lasse Collin 2008-01-14 13:39:54 +02:00
parent b59ef39737
commit e22b37968d
4 changed files with 206 additions and 140 deletions

View file

@ -141,8 +141,9 @@ lzma_lz_encoder_reset(lzma_lz_encoder *lz, lzma_allocator *allocator,
const uint8_t *preset_dictionary,
size_t preset_dictionary_size)
{
// Set uncompressed size.
lz->sequence = SEQ_RUN;
lz->uncompressed_size = uncompressed_size;
lz->temp_size = 0;
///////////////
// In Window //
@ -187,7 +188,6 @@ lzma_lz_encoder_reset(lzma_lz_encoder *lz, lzma_allocator *allocator,
lz->read_pos = 0;
lz->read_limit = 0;
lz->write_pos = 0;
lz->stream_end_was_reached = false;
//////////////////
@ -368,35 +368,59 @@ fill_window(lzma_coder *coder, lzma_allocator *allocator, const uint8_t *in,
size_t *in_pos, size_t in_size, lzma_action action)
{
assert(coder->lz.read_pos <= coder->lz.write_pos);
lzma_ret ret;
// Move the sliding window if needed.
if (coder->lz.read_pos >= coder->lz.size - coder->lz.keep_size_after)
move_window(&coder->lz);
size_t in_used;
lzma_ret ret;
if (coder->next.code == NULL) {
// Not using a filter, simply memcpy() as much as possible.
bufcpy(in, in_pos, in_size, coder->lz.buffer,
in_used = bufcpy(in, in_pos, in_size, coder->lz.buffer,
&coder->lz.write_pos, coder->lz.size);
if (action == LZMA_FINISH && *in_pos == in_size)
if (action != LZMA_RUN && *in_pos == in_size)
ret = LZMA_STREAM_END;
else
ret = LZMA_OK;
} else {
const size_t in_start = *in_pos;
ret = coder->next.code(coder->next.coder, allocator,
in, in_pos, in_size,
coder->lz.buffer, &coder->lz.write_pos,
coder->lz.size, action);
in_used = *in_pos - in_start;
}
// If end of stream has been reached, we allow the encoder to process
// all the input (that is, read_pos is allowed to reach write_pos).
// Otherwise we keep keep_size_after bytes available as prebuffer.
assert(coder->lz.uncompressed_size >= in_used);
if (coder->lz.uncompressed_size != LZMA_VLI_VALUE_UNKNOWN)
coder->lz.uncompressed_size -= in_used;
// If end of stream has been reached or flushing completed, we allow
// the encoder to process all the input (that is, read_pos is allowed
// to reach write_pos). Otherwise we keep keep_size_after bytes
// available as prebuffer.
if (ret == LZMA_STREAM_END) {
coder->lz.stream_end_was_reached = true;
assert(*in_pos == in_size);
coder->lz.read_limit = coder->lz.write_pos;
ret = LZMA_OK;
switch (action) {
case LZMA_SYNC_FLUSH:
coder->lz.sequence = SEQ_FLUSH;
break;
case LZMA_FINISH:
coder->lz.sequence = SEQ_FINISH;
break;
default:
assert(0);
ret = LZMA_PROG_ERROR;
break;
}
} else if (coder->lz.write_pos > coder->lz.keep_size_after) {
// This needs to be done conditionally, because if we got
@ -406,6 +430,19 @@ fill_window(lzma_coder *coder, lzma_allocator *allocator, const uint8_t *in,
- coder->lz.keep_size_after;
}
// Switch to finishing mode if we have got all the input data.
// lzma_lz_encode() won't return LZMA_STREAM_END until LZMA_FINISH
// is used.
//
// NOTE: When LZMA is used together with other filters, it is possible
// that coder->lz.sequence gets set to SEQ_FINISH before the next
// encoder has returned LZMA_STREAM_END. This is somewhat ugly, but
// works correctly, because the next encoder cannot have any more
// output left to be produced. If it had, then our known Uncompressed
// Size would be invalid, which would mean that we have a bad bug.
if (ret == LZMA_OK && coder->lz.uncompressed_size == 0)
coder->lz.sequence = SEQ_FINISH;
return ret;
}
@ -417,22 +454,83 @@ lzma_lz_encode(lzma_coder *coder, lzma_allocator *allocator,
uint8_t *restrict out, size_t *restrict out_pos,
size_t out_size, lzma_action action)
{
while (*out_pos < out_size
&& (*in_pos < in_size || action == LZMA_FINISH)) {
// Fill the input window if there is no more usable data.
if (!coder->lz.stream_end_was_reached && coder->lz.read_pos
>= coder->lz.read_limit) {
const lzma_ret ret = fill_window(coder, allocator,
in, in_pos, in_size, action);
if (ret != LZMA_OK && ret != LZMA_STREAM_END)
return ret;
// Flush the temporary output buffer, which may be used when the
// encoder runs of out of space in primary output buffer (the out,
// *out_pos, and out_size variables).
if (coder->lz.temp_size > 0) {
const size_t out_avail = out_size - *out_pos;
if (out_avail < coder->lz.temp_size) {
// Cannot copy everything. Copy as much as possible
// and move the data in lz.temp to the beginning of
// that buffer.
memcpy(out + *out_pos, coder->lz.temp, out_avail);
*out_pos += out_avail;
memmove(coder->lz.temp, coder->lz.temp + out_avail,
coder->lz.temp_size - out_avail);
coder->lz.temp_size -= out_avail;
return LZMA_OK;
}
// Encode
if (coder->lz.process(coder, out, out_pos, out_size))
// We can copy everything from coder->lz.temp to out.
memcpy(out + *out_pos, coder->lz.temp, coder->lz.temp_size);
*out_pos += coder->lz.temp_size;
coder->lz.temp_size = 0;
}
if (coder->lz.sequence == SEQ_FLUSH_END) {
// During an earlier call to this function, flushing was
// otherwise finished except some data was left pending
// in coder->lz.buffer. Now we have copied all that data
// to the output buffer and can return LZMA_STREAM_END.
coder->lz.sequence = SEQ_RUN;
assert(action == LZMA_SYNC_FLUSH);
return LZMA_STREAM_END;
}
if (coder->lz.sequence == SEQ_END) {
// This is like the above flushing case, but for finishing
// the encoding.
//
// NOTE: action is not necesarily LZMA_FINISH; it can
// be LZMA_SYNC_FLUSH too in case it is used at the
// end of the stream with known Uncompressed Size.
return action != LZMA_RUN ? LZMA_STREAM_END : LZMA_OK;
}
while (*out_pos < out_size
&& (*in_pos < in_size || action != LZMA_RUN)) {
// Read more data to coder->lz.buffer if needed.
if (coder->lz.sequence == SEQ_RUN
&& coder->lz.read_pos >= coder->lz.read_limit)
return_if_error(fill_window(coder, allocator,
in, in_pos, in_size, action));
// Encode
if (coder->lz.process(coder, out, out_pos, out_size)) {
if (coder->lz.sequence == SEQ_FLUSH) {
assert(action == LZMA_SYNC_FLUSH);
if (coder->lz.temp_size == 0) {
// Flushing was finished successfully.
coder->lz.sequence = SEQ_RUN;
} else {
// Flushing was otherwise finished,
// except that some data was left
// into coder->lz.buffer.
coder->lz.sequence = SEQ_FLUSH_END;
}
} else {
// NOTE: action may be LZMA_RUN here in case
// Uncompressed Size is known and we have
// processed all the data already.
assert(coder->lz.sequence == SEQ_FINISH);
coder->lz.sequence = SEQ_END;
}
return action != LZMA_RUN && coder->lz.temp_size == 0
? LZMA_STREAM_END : LZMA_OK;
}
}
return LZMA_OK;
}

View file

@ -24,11 +24,15 @@
#include "common.h"
#define LZMA_LZ_TEMP_SIZE 64
typedef struct lzma_lz_encoder_s lzma_lz_encoder;
struct lzma_lz_encoder_s {
enum {
SEQ_INIT,
SEQ_RUN,
SEQ_FLUSH,
SEQ_FLUSH_END,
SEQ_FINISH,
SEQ_END
} sequence;
@ -36,8 +40,15 @@ struct lzma_lz_encoder_s {
bool (*process)(lzma_coder *coder, uint8_t *restrict out,
size_t *restrict out_pos, size_t out_size);
/// Uncompressed Size or LZMA_VLI_VALUE_UNKNOWN if using EOPM. We need
/// to track Uncompressed Size to prevent writing flush marker to the
/// very end of stream that doesn't use EOPM.
lzma_vli uncompressed_size;
/// Temporary buffer for range encoder.
uint8_t temp[LZMA_LZ_TEMP_SIZE];
size_t temp_size;
///////////////
// In Window //
///////////////
@ -84,10 +95,6 @@ struct lzma_lz_encoder_s {
/// is allowed to reach write_pos).
size_t keep_size_after;
/// This is set to true once the last byte of the input data has
/// been copied to buffer.
bool stream_end_was_reached;
//////////////////
// Match Finder //
//////////////////

View file

@ -149,20 +149,11 @@ extern bool
lzma_lzma_encode(lzma_coder *coder, uint8_t *restrict out,
size_t *restrict out_pos, size_t out_size)
{
// Flush the range encoder's temporary buffer to out[].
// Return immediatelly if not everything could be flushed.
if (rc_flush_buffer(&coder->rc, out, out_pos, out_size))
return false;
// Return immediatelly if we have already finished our work.
if (coder->lz.stream_end_was_reached
&& coder->is_initialized
&& coder->lz.read_pos == coder->lz.write_pos
&& coder->additional_offset == 0)
return true;
#define rc_buffer coder->lz.temp
#define rc_buffer_size coder->lz.temp_size
// Local copies
rc_to_local(coder->rc);
lzma_range_encoder rc = coder->rc;
size_t out_pos_local = *out_pos;
const uint32_t pos_mask = coder->pos_mask;
const bool best_compression = coder->best_compression;
@ -170,13 +161,30 @@ lzma_lzma_encode(lzma_coder *coder, uint8_t *restrict out,
// Initialize the stream if no data has been encoded yet.
if (!coder->is_initialized) {
if (coder->lz.read_pos == coder->lz.read_limit) {
// Cannot initialize, because there is no input data.
if (!coder->lz.stream_end_was_reached)
switch (coder->lz.sequence) {
case SEQ_RUN:
// Cannot initialize, because there is
// no input data.
return false;
// If we get here, we are encoding an empty file.
// Initialization is skipped completely.
case SEQ_FLUSH:
// Nothing to flush. There cannot be a flush
// marker when no data has been processed
// yet (file format doesn't allow it, and
// it would be just waste of space).
return true;
case SEQ_FINISH:
// We are encoding an empty file. No need
// to initialize the encoder.
assert(coder->lz.write_pos == coder->lz.read_pos);
break;
default:
// We never get here.
assert(0);
return true;
}
} else {
// Do the actual initialization.
@ -214,9 +222,10 @@ lzma_lzma_encode(lzma_coder *coder, uint8_t *restrict out,
// Check that there is some input to process.
if (coder->lz.read_pos >= coder->lz.read_limit) {
// If end of input has been reached, we must keep
// encoding until additional_offset becomes zero.
if (!coder->lz.stream_end_was_reached
// If flushing or finishing, we must keep encoding
// until additional_offset becomes zero to make
// all the input available at output.
if (coder->lz.sequence == SEQ_RUN
|| coder->additional_offset == 0)
break;
}
@ -224,7 +233,7 @@ lzma_lzma_encode(lzma_coder *coder, uint8_t *restrict out,
assert(coder->lz.read_pos <= coder->lz.write_pos);
#ifndef NDEBUG
if (coder->lz.stream_end_was_reached) {
if (coder->lz.sequence != SEQ_RUN) {
assert(coder->lz.read_limit == coder->lz.write_pos);
} else {
assert(coder->lz.read_limit + coder->lz.keep_size_after
@ -363,19 +372,21 @@ lzma_lzma_encode(lzma_coder *coder, uint8_t *restrict out,
// Check if everything is done.
bool all_done = false;
if (coder->lz.stream_end_was_reached
if (coder->lz.sequence != SEQ_RUN
&& coder->lz.read_pos == coder->lz.write_pos
&& coder->additional_offset == 0) {
// Write end of stream marker. It is encoded as a match with
// distance of UINT32_MAX. Match length is needed but it is
// ignored by the decoder.
if (coder->lz.uncompressed_size == LZMA_VLI_VALUE_UNKNOWN) {
if (coder->lz.uncompressed_size == LZMA_VLI_VALUE_UNKNOWN
|| coder->lz.sequence == SEQ_FLUSH) {
// Write special marker: flush marker or end of payload
// marker. Both are encoded as a match with distance of
// UINT32_MAX. The match length codes the type of the marker.
const uint32_t pos_state = coder->now_pos & pos_mask;
bit_encode_1(coder->is_match[coder->state][pos_state]);
bit_encode_0(coder->is_rep[coder->state]);
update_match(coder->state);
const uint32_t len = MATCH_MIN_LEN; // MATCH_MAX_LEN;
const uint32_t len = coder->lz.sequence == SEQ_FLUSH
? LEN_SPECIAL_FLUSH : LEN_SPECIAL_EOPM;
length_encode(coder->len_encoder, len - MATCH_MIN_LEN,
pos_state, best_compression);
@ -398,15 +409,16 @@ lzma_lzma_encode(lzma_coder *coder, uint8_t *restrict out,
// the range coder to the output buffer.
rc_flush();
rc_reset(rc);
// All done. Note that some output bytes might be
// pending in coder->buffer. lzma_encode() will
// pending in coder->lz.temp. lzma_lz_encode() will
// take care of those bytes.
if (rc_buffer_size == 0)
all_done = true;
}
// Store local variables back to *coder.
rc_from_local(coder->rc);
coder->rc = rc;
*out_pos = out_pos_local;
return all_done;

View file

@ -24,46 +24,21 @@
#include "range_common.h"
// Allow #including this file even if RC_TEMP_BUFFER_SIZE isn't defined.
#ifdef RC_BUFFER_SIZE
typedef struct {
uint64_t low;
uint32_t range;
uint32_t cache_size;
uint8_t cache;
uint8_t buffer[RC_BUFFER_SIZE];
size_t buffer_size;
} lzma_range_encoder;
#endif
/// Makes local copies of range encoder variables.
#define rc_to_local(rc) \
uint64_t rc_low = (rc).low; \
uint32_t rc_range = (rc).range; \
uint32_t rc_cache_size = (rc).cache_size; \
uint8_t rc_cache = (rc).cache; \
uint8_t *rc_buffer = (rc).buffer; \
size_t rc_buffer_size = (rc).buffer_size
/// Stores the local copes back to the range encoder structure.
#define rc_from_local(rc) \
do { \
(rc).low = rc_low; \
(rc).range = rc_range; \
(rc).cache_size = rc_cache_size; \
(rc).cache = rc_cache; \
(rc).buffer_size = rc_buffer_size; \
} while (0)
/// Resets the range encoder structure.
#define rc_reset(rc) \
do { \
(rc).low = 0; \
(rc).range = 0xFFFFFFFF; \
(rc).range = UINT32_MAX; \
(rc).cache_size = 1; \
(rc).cache = 0; \
(rc).buffer_size = 0; \
} while (0)
@ -72,13 +47,14 @@ do { \
//////////////////
// These macros expect that the following variables are defined:
// - uint64_t rc_low;
// - uint32_t rc_range;
// - uint8_t rc_cache;
// - uint32_t rc_cache_size;
// - lzma_range_encoder rc;
// - uint8_t *out;
// - size_t out_pos_local; // Local copy of *out_pos
// - size_t size_out;
//
// Macros pointing to these variables are also needed:
// - uint8_t rc_buffer[]; // Don't use a pointer, must be real array!
// - size_t rc_buffer_size;
// Combined from NRangeCoder::CEncoder::Encode()
@ -87,13 +63,13 @@ do { \
do { \
probability rc_prob = prob; \
const uint32_t rc_bound \
= (rc_range >> BIT_MODEL_TOTAL_BITS) * rc_prob; \
= (rc.range >> BIT_MODEL_TOTAL_BITS) * rc_prob; \
if ((symbol) == 0) { \
rc_range = rc_bound; \
rc.range = rc_bound; \
rc_prob += (BIT_MODEL_TOTAL - rc_prob) >> MOVE_BITS; \
} else { \
rc_low += rc_bound; \
rc_range -= rc_bound; \
rc.low += rc_bound; \
rc.range -= rc_bound; \
rc_prob -= rc_prob >> MOVE_BITS; \
} \
prob = rc_prob; \
@ -105,7 +81,7 @@ do { \
#define bit_encode_0(prob) \
do { \
probability rc_prob = prob; \
rc_range = (rc_range >> BIT_MODEL_TOTAL_BITS) * rc_prob; \
rc.range = (rc.range >> BIT_MODEL_TOTAL_BITS) * rc_prob; \
rc_prob += (BIT_MODEL_TOTAL - rc_prob) >> MOVE_BITS; \
prob = rc_prob; \
rc_normalize(); \
@ -116,10 +92,10 @@ do { \
#define bit_encode_1(prob) \
do { \
probability rc_prob = prob; \
const uint32_t rc_bound = (rc_range >> BIT_MODEL_TOTAL_BITS) \
const uint32_t rc_bound = (rc.range >> BIT_MODEL_TOTAL_BITS) \
* rc_prob; \
rc_low += rc_bound; \
rc_range -= rc_bound; \
rc.low += rc_bound; \
rc.range -= rc_bound; \
rc_prob -= rc_prob >> MOVE_BITS; \
prob = rc_prob; \
rc_normalize(); \
@ -160,9 +136,9 @@ do { \
#define rc_encode_direct_bits(value, num_total_bits) \
do { \
for (int32_t rc_i = (num_total_bits) - 1; rc_i >= 0; --rc_i) { \
rc_range >>= 1; \
rc.range >>= 1; \
if ((((value) >> rc_i) & 1) == 1) \
rc_low += rc_range; \
rc.low += rc.range; \
rc_normalize(); \
} \
} while (0)
@ -175,8 +151,8 @@ do { \
// Calls rc_shift_low() to write out a byte if needed.
#define rc_normalize() \
do { \
if (rc_range < TOP_VALUE) { \
rc_range <<= SHIFT_BITS; \
if (rc.range < TOP_VALUE) { \
rc.range <<= SHIFT_BITS; \
rc_shift_low(); \
} \
} while (0)
@ -192,23 +168,23 @@ do { \
// TODO: Notation change?
// (uint32_t)(0xFF000000) => ((uint32_t)(0xFF) << TOP_BITS)
// TODO: Another notation change?
// rc_low = (uint32_t)(rc_low) << SHIFT_BITS;
// rc.low = (uint32_t)(rc.low) << SHIFT_BITS;
// =>
// rc_low &= TOP_VALUE - 1;
// rc_low <<= SHIFT_BITS;
// rc.low &= TOP_VALUE - 1;
// rc.low <<= SHIFT_BITS;
#define rc_shift_low() \
do { \
if ((uint32_t)(rc_low) < (uint32_t)(0xFF000000) \
|| (uint32_t)(rc_low >> 32) != 0) { \
uint8_t rc_temp = rc_cache; \
if ((uint32_t)(rc.low) < (uint32_t)(0xFF000000) \
|| (uint32_t)(rc.low >> 32) != 0) { \
uint8_t rc_temp = rc.cache; \
do { \
rc_write_byte(rc_temp + (uint8_t)(rc_low >> 32)); \
rc_write_byte(rc_temp + (uint8_t)(rc.low >> 32)); \
rc_temp = 0xFF; \
} while(--rc_cache_size != 0); \
rc_cache = (uint8_t)((uint32_t)(rc_low) >> 24); \
} while(--rc.cache_size != 0); \
rc.cache = (uint8_t)((uint32_t)(rc.low) >> 24); \
} \
++rc_cache_size; \
rc_low = (uint32_t)(rc_low) << SHIFT_BITS; \
++rc.cache_size; \
rc.low = (uint32_t)(rc.low) << SHIFT_BITS; \
} while (0)
@ -218,7 +194,7 @@ do { \
do { \
if (out_pos_local == out_size) { \
rc_buffer[rc_buffer_size++] = (uint8_t)(b); \
assert(rc_buffer_size < RC_BUFFER_SIZE); \
assert(rc_buffer_size < sizeof(rc_buffer)); \
} else { \
assert(rc_buffer_size == 0); \
out[out_pos_local++] = (uint8_t)(b); \
@ -287,31 +263,4 @@ extern uint32_t lzma_rc_prob_prices[BIT_MODEL_TOTAL >> MOVE_REDUCING_BITS];
extern void lzma_rc_init(void);
#ifdef RC_BUFFER_SIZE
/// Flushes data from rc->temp[] to out[] as much as possible. If everything
/// cannot be flushed, returns true; false otherwise.
static inline bool
rc_flush_buffer(lzma_range_encoder *rc,
uint8_t *out, size_t *out_pos, size_t out_size)
{
if (rc->buffer_size > 0) {
const size_t out_avail = out_size - *out_pos;
if (rc->buffer_size > out_avail) {
memcpy(out + *out_pos, rc->buffer, out_avail);
*out_pos += out_avail;
rc->buffer_size -= out_avail;
memmove(rc->buffer, rc->buffer + out_avail,
rc->buffer_size);
return true;
}
memcpy(out + *out_pos, rc->buffer, rc->buffer_size);
*out_pos += rc->buffer_size;
rc->buffer_size = 0;
}
return false;
}
#endif
#endif