1 files changed, 92 insertions, 0 deletions
diff --git a/src/liblzma/rangecoder/price.h b/src/liblzma/rangecoder/price.h
new file mode 100644
index 0000000..8ae02ca
--- /dev/null
+++ b/src/liblzma/rangecoder/price.h
@@ -0,0 +1,92 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \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.
+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