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author | Lasse Collin <lasse.collin@tukaani.org> | 2008-08-28 22:53:15 +0300 |
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committer | Lasse Collin <lasse.collin@tukaani.org> | 2008-08-28 22:53:15 +0300 |
commit | 3b34851de1eaf358cf9268922fa0eeed8278d680 (patch) | |
tree | 7bab212af647541df64227a8d350d17a2e789f6b /src/liblzma/rangecoder/price.h | |
parent | Fix test_filter_flags to match the new restriction of lc+lp. (diff) | |
download | xz-3b34851de1eaf358cf9268922fa0eeed8278d680.tar.xz |
Sort of garbage collection commit. :-| Many things are still
broken. API has changed a lot and it will still change a
little more here and there. The command line tool doesn't
have all the required changes to reflect the API changes, so
it's easy to get "internal error" or trigger assertions.
Diffstat (limited to 'src/liblzma/rangecoder/price.h')
-rw-r--r-- | src/liblzma/rangecoder/price.h | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/src/liblzma/rangecoder/price.h b/src/liblzma/rangecoder/price.h new file mode 100644 index 00000000..001f753d --- /dev/null +++ b/src/liblzma/rangecoder/price.h @@ -0,0 +1,111 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file price.h +/// \brief Probability price calculation +// +// Copyright (C) 1999-2008 Igor Pavlov +// +// This library is free software; you can redistribute it and/or +// modify it under the terms of the GNU Lesser General Public +// License as published by the Free Software Foundation; either +// version 2.1 of the License, or (at your option) any later version. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// Lesser General Public License for more details. +// +/////////////////////////////////////////////////////////////////////////////// + +#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) + + +#if !defined(LZMA_RANGE_ENCODER_H) || defined(HAVE_SMALL) +/// Probability prices used by *_get_price() macros. This is initialized +/// by lzma_rc_init() and is not modified later. +extern uint32_t lzma_rc_prices[RC_PRICE_TABLE_SIZE]; + +/// Initializes lzma_rc_prices[]. This needs to be called only once. +extern void lzma_rc_init(void); + +#else +// Not building a size optimized version, so we use a precomputed +// constant table. +extern const uint32_t lzma_rc_prices[RC_PRICE_TABLE_SIZE]; + +#endif + + +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 |