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-rw-r--r--src/liblzma/rangecoder/Makefile.inc21
-rw-r--r--src/liblzma/rangecoder/price.h93
-rw-r--r--src/liblzma/rangecoder/price_table.c22
-rw-r--r--src/liblzma/rangecoder/price_tablegen.c87
-rw-r--r--src/liblzma/rangecoder/range_common.h71
-rw-r--r--src/liblzma/rangecoder/range_decoder.h185
-rw-r--r--src/liblzma/rangecoder/range_encoder.h350
7 files changed, 829 insertions, 0 deletions
diff --git a/src/liblzma/rangecoder/Makefile.inc b/src/liblzma/rangecoder/Makefile.inc
new file mode 100644
index 0000000..d8a597a
--- /dev/null
+++ b/src/liblzma/rangecoder/Makefile.inc
@@ -0,0 +1,21 @@
+##
+## Author: Lasse Collin
+##
+## This file has been put into the public domain.
+## You can do whatever you want with this file.
+##
+
+EXTRA_DIST += rangecoder/price_tablegen.c
+
+liblzma_la_SOURCES += rangecoder/range_common.h
+
+if COND_ENCODER_LZMA1
+liblzma_la_SOURCES += \
+ rangecoder/range_encoder.h \
+ rangecoder/price.h \
+ rangecoder/price_table.c
+endif
+
+if COND_DECODER_LZMA1
+liblzma_la_SOURCES += rangecoder/range_decoder.h
+endif
diff --git a/src/liblzma/rangecoder/price.h b/src/liblzma/rangecoder/price.h
new file mode 100644
index 0000000..45dbbbb
--- /dev/null
+++ b/src/liblzma/rangecoder/price.h
@@ -0,0 +1,93 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file price.h
+/// \brief Probability price calculation
+//
+// Author: Igor Pavlov
+//
+// This file has been put into the public domain.
+// You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef LZMA_PRICE_H
+#define LZMA_PRICE_H
+
+
+#define RC_MOVE_REDUCING_BITS 4
+#define RC_BIT_PRICE_SHIFT_BITS 4
+#define RC_PRICE_TABLE_SIZE (RC_BIT_MODEL_TOTAL >> RC_MOVE_REDUCING_BITS)
+
+#define RC_INFINITY_PRICE (UINT32_C(1) << 30)
+
+
+/// Lookup table for the inline functions defined in this file.
+lzma_attr_visibility_hidden
+extern const uint8_t lzma_rc_prices[RC_PRICE_TABLE_SIZE];
+
+
+static inline uint32_t
+rc_bit_price(const probability prob, const uint32_t bit)
+{
+ return lzma_rc_prices[(prob ^ ((UINT32_C(0) - bit)
+ & (RC_BIT_MODEL_TOTAL - 1))) >> RC_MOVE_REDUCING_BITS];
+}
+
+
+static inline uint32_t
+rc_bit_0_price(const probability prob)
+{
+ return lzma_rc_prices[prob >> RC_MOVE_REDUCING_BITS];
+}
+
+
+static inline uint32_t
+rc_bit_1_price(const probability prob)
+{
+ return lzma_rc_prices[(prob ^ (RC_BIT_MODEL_TOTAL - 1))
+ >> RC_MOVE_REDUCING_BITS];
+}
+
+
+static inline uint32_t
+rc_bittree_price(const probability *const probs,
+ const uint32_t bit_levels, uint32_t symbol)
+{
+ uint32_t price = 0;
+ symbol += UINT32_C(1) << bit_levels;
+
+ do {
+ const uint32_t bit = symbol & 1;
+ symbol >>= 1;
+ price += rc_bit_price(probs[symbol], bit);
+ } while (symbol != 1);
+
+ return price;
+}
+
+
+static inline uint32_t
+rc_bittree_reverse_price(const probability *const probs,
+ uint32_t bit_levels, uint32_t symbol)
+{
+ uint32_t price = 0;
+ uint32_t model_index = 1;
+
+ do {
+ const uint32_t bit = symbol & 1;
+ symbol >>= 1;
+ price += rc_bit_price(probs[model_index], bit);
+ model_index = (model_index << 1) + bit;
+ } while (--bit_levels != 0);
+
+ return price;
+}
+
+
+static inline uint32_t
+rc_direct_price(const uint32_t bits)
+{
+ return bits << RC_BIT_PRICE_SHIFT_BITS;
+}
+
+#endif
diff --git a/src/liblzma/rangecoder/price_table.c b/src/liblzma/rangecoder/price_table.c
new file mode 100644
index 0000000..ac64bf6
--- /dev/null
+++ b/src/liblzma/rangecoder/price_table.c
@@ -0,0 +1,22 @@
+/* This file has been automatically generated by price_tablegen.c. */
+
+#include "range_encoder.h"
+
+const uint8_t lzma_rc_prices[RC_PRICE_TABLE_SIZE] = {
+ 128, 103, 91, 84, 78, 73, 69, 66,
+ 63, 61, 58, 56, 54, 52, 51, 49,
+ 48, 46, 45, 44, 43, 42, 41, 40,
+ 39, 38, 37, 36, 35, 34, 34, 33,
+ 32, 31, 31, 30, 29, 29, 28, 28,
+ 27, 26, 26, 25, 25, 24, 24, 23,
+ 23, 22, 22, 22, 21, 21, 20, 20,
+ 19, 19, 19, 18, 18, 17, 17, 17,
+ 16, 16, 16, 15, 15, 15, 14, 14,
+ 14, 13, 13, 13, 12, 12, 12, 11,
+ 11, 11, 11, 10, 10, 10, 10, 9,
+ 9, 9, 9, 8, 8, 8, 8, 7,
+ 7, 7, 7, 6, 6, 6, 6, 5,
+ 5, 5, 5, 5, 4, 4, 4, 4,
+ 3, 3, 3, 3, 3, 2, 2, 2,
+ 2, 2, 2, 1, 1, 1, 1, 1
+};
diff --git a/src/liblzma/rangecoder/price_tablegen.c b/src/liblzma/rangecoder/price_tablegen.c
new file mode 100644
index 0000000..bf08ce3
--- /dev/null
+++ b/src/liblzma/rangecoder/price_tablegen.c
@@ -0,0 +1,87 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file price_tablegen.c
+/// \brief Probability price table generator
+///
+/// Compiling: gcc -std=c99 -o price_tablegen price_tablegen.c
+///
+// Authors: Igor Pavlov
+// Lasse Collin
+//
+// This file has been put into the public domain.
+// You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include <inttypes.h>
+#include <stdio.h>
+#include "range_common.h"
+#include "price.h"
+
+
+static uint32_t rc_prices[RC_PRICE_TABLE_SIZE];
+
+
+static void
+init_price_table(void)
+{
+ for (uint32_t i = (UINT32_C(1) << RC_MOVE_REDUCING_BITS) / 2;
+ i < RC_BIT_MODEL_TOTAL;
+ i += (UINT32_C(1) << RC_MOVE_REDUCING_BITS)) {
+ const uint32_t cycles_bits = RC_BIT_PRICE_SHIFT_BITS;
+ uint32_t w = i;
+ uint32_t bit_count = 0;
+
+ for (uint32_t j = 0; j < cycles_bits; ++j) {
+ w *= w;
+ bit_count <<= 1;
+
+ while (w >= (UINT32_C(1) << 16)) {
+ w >>= 1;
+ ++bit_count;
+ }
+ }
+
+ rc_prices[i >> RC_MOVE_REDUCING_BITS]
+ = (RC_BIT_MODEL_TOTAL_BITS << cycles_bits)
+ - 15 - bit_count;
+ }
+
+ return;
+}
+
+
+static void
+print_price_table(void)
+{
+ printf("/* This file has been automatically generated by "
+ "price_tablegen.c. */\n\n"
+ "#include \"range_encoder.h\"\n\n"
+ "const uint8_t lzma_rc_prices["
+ "RC_PRICE_TABLE_SIZE] = {");
+
+ const size_t array_size = sizeof(lzma_rc_prices)
+ / sizeof(lzma_rc_prices[0]);
+ for (size_t i = 0; i < array_size; ++i) {
+ if (i % 8 == 0)
+ printf("\n\t");
+
+ printf("%4" PRIu32, rc_prices[i]);
+
+ if (i != array_size - 1)
+ printf(",");
+ }
+
+ printf("\n};\n");
+
+ return;
+}
+
+
+int
+main(void)
+{
+ init_price_table();
+ print_price_table();
+ return 0;
+}
diff --git a/src/liblzma/rangecoder/range_common.h b/src/liblzma/rangecoder/range_common.h
new file mode 100644
index 0000000..2c74dc1
--- /dev/null
+++ b/src/liblzma/rangecoder/range_common.h
@@ -0,0 +1,71 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file range_common.h
+/// \brief Common things for range encoder and decoder
+///
+// Authors: Igor Pavlov
+// Lasse Collin
+//
+// This file has been put into the public domain.
+// You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef LZMA_RANGE_COMMON_H
+#define LZMA_RANGE_COMMON_H
+
+#include "common.h"
+
+
+///////////////
+// Constants //
+///////////////
+
+#define RC_SHIFT_BITS 8
+#define RC_TOP_BITS 24
+#define RC_TOP_VALUE (UINT32_C(1) << RC_TOP_BITS)
+#define RC_BIT_MODEL_TOTAL_BITS 11
+#define RC_BIT_MODEL_TOTAL (UINT32_C(1) << RC_BIT_MODEL_TOTAL_BITS)
+#define RC_MOVE_BITS 5
+
+
+////////////
+// Macros //
+////////////
+
+// Resets the probability so that both 0 and 1 have probability of 50 %
+#define bit_reset(prob) \
+ prob = RC_BIT_MODEL_TOTAL >> 1
+
+// This does the same for a complete bit tree.
+// (A tree represented as an array.)
+#define bittree_reset(probs, bit_levels) \
+ for (uint32_t bt_i = 0; bt_i < (1 << (bit_levels)); ++bt_i) \
+ bit_reset((probs)[bt_i])
+
+
+//////////////////////
+// Type definitions //
+//////////////////////
+
+/// \brief Type of probabilities used with range coder
+///
+/// This needs to be at least 12-bit integer, so uint16_t is a logical choice.
+/// However, on some architecture and compiler combinations, a bigger type
+/// may give better speed, because the probability variables are accessed
+/// a lot. On the other hand, bigger probability type increases cache
+/// footprint, since there are 2 to 14 thousand probability variables in
+/// LZMA (assuming the limit of lc + lp <= 4; with lc + lp <= 12 there
+/// would be about 1.5 million variables).
+///
+/// With malicious files, the initialization speed of the LZMA decoder can
+/// become important. In that case, smaller probability variables mean that
+/// there is less bytes to write to RAM, which makes initialization faster.
+/// With big probability type, the initialization can become so slow that it
+/// can be a problem e.g. for email servers doing virus scanning.
+///
+/// I will be sticking to uint16_t unless some specific architectures
+/// are *much* faster (20-50 %) with uint32_t.
+typedef uint16_t probability;
+
+#endif
diff --git a/src/liblzma/rangecoder/range_decoder.h b/src/liblzma/rangecoder/range_decoder.h
new file mode 100644
index 0000000..e0b051f
--- /dev/null
+++ b/src/liblzma/rangecoder/range_decoder.h
@@ -0,0 +1,185 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file range_decoder.h
+/// \brief Range Decoder
+///
+// Authors: Igor Pavlov
+// Lasse Collin
+//
+// This file has been put into the public domain.
+// You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef LZMA_RANGE_DECODER_H
+#define LZMA_RANGE_DECODER_H
+
+#include "range_common.h"
+
+
+typedef struct {
+ uint32_t range;
+ uint32_t code;
+ uint32_t init_bytes_left;
+} lzma_range_decoder;
+
+
+/// Reads the first five bytes to initialize the range decoder.
+static inline lzma_ret
+rc_read_init(lzma_range_decoder *rc, const uint8_t *restrict in,
+ size_t *restrict in_pos, size_t in_size)
+{
+ while (rc->init_bytes_left > 0) {
+ if (*in_pos == in_size)
+ return LZMA_OK;
+
+ // The first byte is always 0x00. It could have been omitted
+ // in LZMA2 but it wasn't, so one byte is wasted in every
+ // LZMA2 chunk.
+ if (rc->init_bytes_left == 5 && in[*in_pos] != 0x00)
+ return LZMA_DATA_ERROR;
+
+ rc->code = (rc->code << 8) | in[*in_pos];
+ ++*in_pos;
+ --rc->init_bytes_left;
+ }
+
+ return LZMA_STREAM_END;
+}
+
+
+/// Makes local copies of range decoder and *in_pos variables. Doing this
+/// improves speed significantly. The range decoder macros expect also
+/// variables `in' and `in_size' to be defined.
+#define rc_to_local(range_decoder, in_pos) \
+ lzma_range_decoder rc = range_decoder; \
+ size_t rc_in_pos = (in_pos); \
+ uint32_t rc_bound
+
+
+/// Stores the local copes back to the range decoder structure.
+#define rc_from_local(range_decoder, in_pos) \
+do { \
+ range_decoder = rc; \
+ in_pos = rc_in_pos; \
+} while (0)
+
+
+/// Resets the range decoder structure.
+#define rc_reset(range_decoder) \
+do { \
+ (range_decoder).range = UINT32_MAX; \
+ (range_decoder).code = 0; \
+ (range_decoder).init_bytes_left = 5; \
+} while (0)
+
+
+/// When decoding has been properly finished, rc.code is always zero unless
+/// the input stream is corrupt. So checking this can catch some corrupt
+/// files especially if they don't have any other integrity check.
+#define rc_is_finished(range_decoder) \
+ ((range_decoder).code == 0)
+
+
+/// Read the next input byte if needed. If more input is needed but there is
+/// no more input available, "goto out" is used to jump out of the main
+/// decoder loop.
+#define rc_normalize(seq) \
+do { \
+ if (rc.range < RC_TOP_VALUE) { \
+ if (unlikely(rc_in_pos == in_size)) { \
+ coder->sequence = seq; \
+ goto out; \
+ } \
+ rc.range <<= RC_SHIFT_BITS; \
+ rc.code = (rc.code << RC_SHIFT_BITS) | in[rc_in_pos++]; \
+ } \
+} while (0)
+
+
+/// Start decoding a bit. This must be used together with rc_update_0()
+/// and rc_update_1():
+///
+/// rc_if_0(prob, seq) {
+/// rc_update_0(prob);
+/// // Do something
+/// } else {
+/// rc_update_1(prob);
+/// // Do something else
+/// }
+///
+#define rc_if_0(prob, seq) \
+ rc_normalize(seq); \
+ rc_bound = (rc.range >> RC_BIT_MODEL_TOTAL_BITS) * (prob); \
+ if (rc.code < rc_bound)
+
+
+/// Update the range decoder state and the used probability variable to
+/// match a decoded bit of 0.
+#define rc_update_0(prob) \
+do { \
+ rc.range = rc_bound; \
+ prob += (RC_BIT_MODEL_TOTAL - (prob)) >> RC_MOVE_BITS; \
+} while (0)
+
+
+/// Update the range decoder state and the used probability variable to
+/// match a decoded bit of 1.
+#define rc_update_1(prob) \
+do { \
+ rc.range -= rc_bound; \
+ rc.code -= rc_bound; \
+ prob -= (prob) >> RC_MOVE_BITS; \
+} while (0)
+
+
+/// Decodes one bit and runs action0 or action1 depending on the decoded bit.
+/// This macro is used as the last step in bittree reverse decoders since
+/// those don't use "symbol" for anything else than indexing the probability
+/// arrays.
+#define rc_bit_last(prob, action0, action1, seq) \
+do { \
+ rc_if_0(prob, seq) { \
+ rc_update_0(prob); \
+ action0; \
+ } else { \
+ rc_update_1(prob); \
+ action1; \
+ } \
+} while (0)
+
+
+/// Decodes one bit, updates "symbol", and runs action0 or action1 depending
+/// on the decoded bit.
+#define rc_bit(prob, action0, action1, seq) \
+ rc_bit_last(prob, \
+ symbol <<= 1; action0, \
+ symbol = (symbol << 1) + 1; action1, \
+ seq);
+
+
+/// Like rc_bit() but add "case seq:" as a prefix. This makes the unrolled
+/// loops more readable because the code isn't littered with "case"
+/// statements. On the other hand this also makes it less readable, since
+/// spotting the places where the decoder loop may be restarted is less
+/// obvious.
+#define rc_bit_case(prob, action0, action1, seq) \
+ case seq: rc_bit(prob, action0, action1, seq)
+
+
+/// Decode a bit without using a probability.
+#define rc_direct(dest, seq) \
+do { \
+ rc_normalize(seq); \
+ rc.range >>= 1; \
+ rc.code -= rc.range; \
+ rc_bound = UINT32_C(0) - (rc.code >> 31); \
+ rc.code += rc.range & rc_bound; \
+ dest = (dest << 1) + (rc_bound + 1); \
+} while (0)
+
+
+// NOTE: No macros are provided for bittree decoding. It seems to be simpler
+// to just write them open in the code.
+
+#endif
diff --git a/src/liblzma/rangecoder/range_encoder.h b/src/liblzma/rangecoder/range_encoder.h
new file mode 100644
index 0000000..d794eab
--- /dev/null
+++ b/src/liblzma/rangecoder/range_encoder.h
@@ -0,0 +1,350 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file range_encoder.h
+/// \brief Range Encoder
+///
+// Authors: Igor Pavlov
+// Lasse Collin
+//
+// This file has been put into the public domain.
+// You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#ifndef LZMA_RANGE_ENCODER_H
+#define LZMA_RANGE_ENCODER_H
+
+#include "range_common.h"
+#include "price.h"
+
+
+/// Maximum number of symbols that can be put pending into lzma_range_encoder
+/// structure between calls to lzma_rc_encode(). For LZMA, 48+5 is enough
+/// (match with big distance and length followed by range encoder flush).
+#define RC_SYMBOLS_MAX 53
+
+
+typedef struct {
+ uint64_t low;
+ uint64_t cache_size;
+ uint32_t range;
+ uint8_t cache;
+
+ /// Number of bytes written out by rc_encode() -> rc_shift_low()
+ uint64_t out_total;
+
+ /// Number of symbols in the tables
+ size_t count;
+
+ /// rc_encode()'s position in the tables
+ size_t pos;
+
+ /// Symbols to encode
+ enum {
+ RC_BIT_0,
+ RC_BIT_1,
+ RC_DIRECT_0,
+ RC_DIRECT_1,
+ RC_FLUSH,
+ } symbols[RC_SYMBOLS_MAX];
+
+ /// Probabilities associated with RC_BIT_0 or RC_BIT_1
+ probability *probs[RC_SYMBOLS_MAX];
+
+} lzma_range_encoder;
+
+
+static inline void
+rc_reset(lzma_range_encoder *rc)
+{
+ rc->low = 0;
+ rc->cache_size = 1;
+ rc->range = UINT32_MAX;
+ rc->cache = 0;
+ rc->out_total = 0;
+ rc->count = 0;
+ rc->pos = 0;
+}
+
+
+static inline void
+rc_forget(lzma_range_encoder *rc)
+{
+ // This must not be called when rc_encode() is partially done.
+ assert(rc->pos == 0);
+ rc->count = 0;
+}
+
+
+static inline void
+rc_bit(lzma_range_encoder *rc, probability *prob, uint32_t bit)
+{
+ rc->symbols[rc->count] = bit;
+ rc->probs[rc->count] = prob;
+ ++rc->count;
+}
+
+
+static inline void
+rc_bittree(lzma_range_encoder *rc, probability *probs,
+ uint32_t bit_count, uint32_t symbol)
+{
+ uint32_t model_index = 1;
+
+ do {
+ const uint32_t bit = (symbol >> --bit_count) & 1;
+ rc_bit(rc, &probs[model_index], bit);
+ model_index = (model_index << 1) + bit;
+ } while (bit_count != 0);
+}
+
+
+static inline void
+rc_bittree_reverse(lzma_range_encoder *rc, probability *probs,
+ uint32_t bit_count, uint32_t symbol)
+{
+ uint32_t model_index = 1;
+
+ do {
+ const uint32_t bit = symbol & 1;
+ symbol >>= 1;
+ rc_bit(rc, &probs[model_index], bit);
+ model_index = (model_index << 1) + bit;
+ } while (--bit_count != 0);
+}
+
+
+static inline void
+rc_direct(lzma_range_encoder *rc,
+ uint32_t value, uint32_t bit_count)
+{
+ do {
+ rc->symbols[rc->count++]
+ = RC_DIRECT_0 + ((value >> --bit_count) & 1);
+ } while (bit_count != 0);
+}
+
+
+static inline void
+rc_flush(lzma_range_encoder *rc)
+{
+ for (size_t i = 0; i < 5; ++i)
+ rc->symbols[rc->count++] = RC_FLUSH;
+}
+
+
+static inline bool
+rc_shift_low(lzma_range_encoder *rc,
+ uint8_t *out, size_t *out_pos, size_t out_size)
+{
+ if ((uint32_t)(rc->low) < (uint32_t)(0xFF000000)
+ || (uint32_t)(rc->low >> 32) != 0) {
+ do {
+ if (*out_pos == out_size)
+ return true;
+
+ out[*out_pos] = rc->cache + (uint8_t)(rc->low >> 32);
+ ++*out_pos;
+ ++rc->out_total;
+ rc->cache = 0xFF;
+
+ } while (--rc->cache_size != 0);
+
+ rc->cache = (rc->low >> 24) & 0xFF;
+ }
+
+ ++rc->cache_size;
+ rc->low = (rc->low & 0x00FFFFFF) << RC_SHIFT_BITS;
+
+ return false;
+}
+
+
+// NOTE: The last two arguments are uint64_t instead of size_t because in
+// the dummy version these refer to the size of the whole range-encoded
+// output stream, not just to the currently available output buffer space.
+static inline bool
+rc_shift_low_dummy(uint64_t *low, uint64_t *cache_size, uint8_t *cache,
+ uint64_t *out_pos, uint64_t out_size)
+{
+ if ((uint32_t)(*low) < (uint32_t)(0xFF000000)
+ || (uint32_t)(*low >> 32) != 0) {
+ do {
+ if (*out_pos == out_size)
+ return true;
+
+ ++*out_pos;
+ *cache = 0xFF;
+
+ } while (--*cache_size != 0);
+
+ *cache = (*low >> 24) & 0xFF;
+ }
+
+ ++*cache_size;
+ *low = (*low & 0x00FFFFFF) << RC_SHIFT_BITS;
+
+ return false;
+}
+
+
+static inline bool
+rc_encode(lzma_range_encoder *rc,
+ uint8_t *out, size_t *out_pos, size_t out_size)
+{
+ assert(rc->count <= RC_SYMBOLS_MAX);
+
+ while (rc->pos < rc->count) {
+ // Normalize
+ if (rc->range < RC_TOP_VALUE) {
+ if (rc_shift_low(rc, out, out_pos, out_size))
+ return true;
+
+ rc->range <<= RC_SHIFT_BITS;
+ }
+
+ // Encode a bit
+ switch (rc->symbols[rc->pos]) {
+ case RC_BIT_0: {
+ probability prob = *rc->probs[rc->pos];
+ rc->range = (rc->range >> RC_BIT_MODEL_TOTAL_BITS)
+ * prob;
+ prob += (RC_BIT_MODEL_TOTAL - prob) >> RC_MOVE_BITS;
+ *rc->probs[rc->pos] = prob;
+ break;
+ }
+
+ case RC_BIT_1: {
+ probability prob = *rc->probs[rc->pos];
+ const uint32_t bound = prob * (rc->range
+ >> RC_BIT_MODEL_TOTAL_BITS);
+ rc->low += bound;
+ rc->range -= bound;
+ prob -= prob >> RC_MOVE_BITS;
+ *rc->probs[rc->pos] = prob;
+ break;
+ }
+
+ case RC_DIRECT_0:
+ rc->range >>= 1;
+ break;
+
+ case RC_DIRECT_1:
+ rc->range >>= 1;
+ rc->low += rc->range;
+ break;
+
+ case RC_FLUSH:
+ // Prevent further normalizations.
+ rc->range = UINT32_MAX;
+
+ // Flush the last five bytes (see rc_flush()).
+ do {
+ if (rc_shift_low(rc, out, out_pos, out_size))
+ return true;
+ } while (++rc->pos < rc->count);
+
+ // Reset the range encoder so we are ready to continue
+ // encoding if we weren't finishing the stream.
+ rc_reset(rc);
+ return false;
+
+ default:
+ assert(0);
+ break;
+ }
+
+ ++rc->pos;
+ }
+
+ rc->count = 0;
+ rc->pos = 0;
+
+ return false;
+}
+
+
+static inline bool
+rc_encode_dummy(const lzma_range_encoder *rc, uint64_t out_limit)
+{
+ assert(rc->count <= RC_SYMBOLS_MAX);
+
+ uint64_t low = rc->low;
+ uint64_t cache_size = rc->cache_size;
+ uint32_t range = rc->range;
+ uint8_t cache = rc->cache;
+ uint64_t out_pos = rc->out_total;
+
+ size_t pos = rc->pos;
+
+ while (true) {
+ // Normalize
+ if (range < RC_TOP_VALUE) {
+ if (rc_shift_low_dummy(&low, &cache_size, &cache,
+ &out_pos, out_limit))
+ return true;
+
+ range <<= RC_SHIFT_BITS;
+ }
+
+ // This check is here because the normalization above must
+ // be done before flushing the last bytes.
+ if (pos == rc->count)
+ break;
+
+ // Encode a bit
+ switch (rc->symbols[pos]) {
+ case RC_BIT_0: {
+ probability prob = *rc->probs[pos];
+ range = (range >> RC_BIT_MODEL_TOTAL_BITS)
+ * prob;
+ break;
+ }
+
+ case RC_BIT_1: {
+ probability prob = *rc->probs[pos];
+ const uint32_t bound = prob * (range
+ >> RC_BIT_MODEL_TOTAL_BITS);
+ low += bound;
+ range -= bound;
+ break;
+ }
+
+ case RC_DIRECT_0:
+ range >>= 1;
+ break;
+
+ case RC_DIRECT_1:
+ range >>= 1;
+ low += range;
+ break;
+
+ case RC_FLUSH:
+ default:
+ assert(0);
+ break;
+ }
+
+ ++pos;
+ }
+
+ // Flush the last bytes. This isn't in rc->symbols[] so we do
+ // it after the above loop to take into account the size of
+ // the flushing that will be done at the end of the stream.
+ for (pos = 0; pos < 5; ++pos) {
+ if (rc_shift_low_dummy(&low, &cache_size,
+ &cache, &out_pos, out_limit))
+ return true;
+ }
+
+ return false;
+}
+
+
+static inline uint64_t
+rc_pending(const lzma_range_encoder *rc)
+{
+ return rc->cache_size + 5 - 1;
+}
+
+#endif
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-22 06:32:16 +0000