X-Git-Url: https://wimlib.net/git/?a=blobdiff_plain;ds=sidebyside;f=include%2Fwimlib%2Flzms_common.h;h=1cb8c5660f7eff73a99a433e578105e62a9a1234;hb=5fce6aa92826ec69fdeeea13e28292fa1fbb43a8;hp=10dc4d020a3b3240252366abee98b4c070064e6b;hpb=40a690416a3951361ec77d33a723dd4497fb7585;p=wimlib

diff --git a/include/wimlib/lzms_common.h b/include/wimlib/lzms_common.h
index 10dc4d02..1cb8c566 100644
--- a/include/wimlib/lzms_common.h
+++ b/include/wimlib/lzms_common.h
@@ -11,36 +11,6 @@
 #include "wimlib/lzms_constants.h"
 #include "wimlib/types.h"
 
-//#define ENABLE_LZMS_DEBUG
-#ifdef ENABLE_LZMS_DEBUG
-#	define LZMS_DEBUG DEBUG
-#       define LZMS_ASSERT wimlib_assert
-#       include "wimlib/assert.h"
-#       include "wimlib/error.h"
-#else
-#	define LZMS_DEBUG(format, ...)
-#	define LZMS_ASSERT(...)
-#endif
-
-extern void
-lzms_x86_filter(u8 data[], s32 size, s32 last_target_usages[], bool undo);
-
-/* Probability entry for use by the range coder when in a specific state.  */
-struct lzms_probability_entry {
-
-	/* Number of zeroes in the most recent LZMS_PROBABILITY_MAX bits that
-	 * have been coded using this probability entry.  This is a cached value
-	 * because it can be computed as LZMS_PROBABILITY_MAX minus the number
-	 * of bits set in the low-order LZMS_PROBABILITY_MAX bits of
-	 * @recent_bits.  */
-	u32 num_recent_zero_bits;
-
-	/* The most recent LZMS_PROBABILITY_MAX bits that have been coded using
-	 * this probability entry.  The size of this variable, in bits, must be
-	 * at least LZMS_PROBABILITY_MAX.  */
-	u64 recent_bits;
-};
-
 /* Offset slot tables  */
 extern const u32 lzms_offset_slot_base[LZMS_MAX_NUM_OFFSET_SYMS + 1];
 extern const u8 lzms_extra_offset_bits[LZMS_MAX_NUM_OFFSET_SYMS];
@@ -69,42 +39,62 @@ lzms_get_length_slot(u32 length)
 extern unsigned
 lzms_get_num_offset_slots(size_t uncompressed_size);
 
-extern void
-lzms_init_probability_entries(struct lzms_probability_entry *entries, size_t count);
+
+/* Probability entry for use by the range coder when in a specific state  */
+struct lzms_probability_entry {
+
+	/* The number of zeroes in the most recent LZMS_PROBABILITY_DENOMINATOR
+	 * bits that have been decoded or encoded using this probability entry.
+	 * The probability of the next bit being 0 is this value over
+	 * LZMS_PROBABILITY_DENOMINATOR, except for the cases where this would
+	 * imply 0% or 100% probability.  */
+	u32 num_recent_zero_bits;
+
+	/* The most recent LZMS_PROBABILITY_DENOMINATOR bits that have been
+	 * coded using this probability entry.  The bits are ordered such that
+	 * low order is newest and high order is oldest.  */
+	u64 recent_bits;
+};
 
 extern void
-lzms_init_symbol_frequencies(u32 freqs[], size_t num_syms);
+lzms_init_probability_entries(struct lzms_probability_entry *entries, size_t count);
 
-/* Given a decoded bit, update the probability entry.  */
+/* Given a decoded or encoded bit, update the probability entry.  */
 static inline void
-lzms_update_probability_entry(struct lzms_probability_entry *prob_entry, int bit)
+lzms_update_probability_entry(struct lzms_probability_entry *entry, int bit)
 {
-	s32 delta_zero_bits;
+	BUILD_BUG_ON(LZMS_PROBABILITY_DENOMINATOR != sizeof(entry->recent_bits) * 8);
 
-	BUILD_BUG_ON(LZMS_PROBABILITY_MAX != sizeof(prob_entry->recent_bits) * 8);
+	s32 delta_zero_bits = (s32)(entry->recent_bits >>
+				    (LZMS_PROBABILITY_DENOMINATOR - 1)) - bit;
 
-	delta_zero_bits = (s32)(prob_entry->recent_bits >> (LZMS_PROBABILITY_MAX - 1)) - bit;
-
-	prob_entry->num_recent_zero_bits += delta_zero_bits;
-	prob_entry->recent_bits <<= 1;
-	prob_entry->recent_bits |= bit;
+	entry->num_recent_zero_bits += delta_zero_bits;
+	entry->recent_bits = (entry->recent_bits << 1) | bit;
 }
 
-/* Given a probability entry, return the chance out of LZMS_PROBABILITY_MAX that
- * the next decoded bit will be a 0.  */
+/* Given a probability entry, return the chance out of
+ * LZMS_PROBABILITY_DENOMINATOR that the next decoded bit will be a 0.  */
 static inline u32
 lzms_get_probability(const struct lzms_probability_entry *prob_entry)
 {
-	u32 prob;
-
-	prob = prob_entry->num_recent_zero_bits;
+	u32 prob = prob_entry->num_recent_zero_bits;
 
 	/* 0% and 100% probabilities aren't allowed.  */
 	if (prob == 0)
 		prob++;
-	if (prob == LZMS_PROBABILITY_MAX)
+	else if (prob == LZMS_PROBABILITY_DENOMINATOR)
 		prob--;
 	return prob;
 }
 
+extern void
+lzms_init_symbol_frequencies(u32 freqs[], unsigned num_syms);
+
+extern void
+lzms_dilute_symbol_frequencies(u32 freqs[], unsigned num_syms);
+
+/* Pre/post-processing  */
+extern void
+lzms_x86_filter(u8 data[], s32 size, s32 last_target_usages[], bool undo);
+
 #endif /* _LZMS_COMMON_H */