Bitcoin ABC
0.26.3
P2P Digital Currency
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src
util
golombrice.h
Go to the documentation of this file.
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// Copyright (c) 2018-2019 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#ifndef BITCOIN_UTIL_GOLOMBRICE_H
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#define BITCOIN_UTIL_GOLOMBRICE_H
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#include <
streams.h
>
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#include <cstdint>
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template
<
typename
OStream>
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static
void
GolombRiceEncode
(
BitStreamWriter<OStream>
&
bitwriter
,
uint8_t
P
,
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uint64_t
x) {
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// Write quotient as unary-encoded: q 1's followed by one 0.
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uint64_t
q = x >>
P
;
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while
(q > 0) {
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int
nbits
=
q <= 64 ? static_cast<int>
(q) : 64;
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bitwriter
.Write(~0
ULL
,
nbits
);
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q -=
nbits
;
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}
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bitwriter
.Write(0, 1);
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// Write the remainder in P bits. Since the remainder is just the bottom
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// P bits of x, there is no need to mask first.
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bitwriter
.Write(x,
P
);
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}
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template
<
typename
IStream>
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static
uint64_t
GolombRiceDecode
(
BitStreamReader<IStream>
&
bitreader
,
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uint8_t
P
) {
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// Read unary-encoded quotient: q 1's followed by one 0.
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uint64_t
q = 0;
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while
(
bitreader
.Read(1) == 1) {
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++q;
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}
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uint64_t
r =
bitreader
.Read(
P
);
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return
(q <<
P
) + r;
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}
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#endif
// BITCOIN_UTIL_GOLOMBRICE_H
BitStreamReader
Definition
streams.h:425
BitStreamWriter
Definition
streams.h:467
GolombRiceDecode
static uint64_t GolombRiceDecode(BitStreamReader< IStream > &bitreader, uint8_t P)
Definition
golombrice.h:30
GolombRiceEncode
static void GolombRiceEncode(BitStreamWriter< OStream > &bitwriter, uint8_t P, uint64_t x)
Definition
golombrice.h:13
GetRand
T GetRand(T nMax=std::numeric_limits< T >::max()) noexcept
Generate a uniform random integer of type T in the range [0..nMax) nMax defaults to std::numeric_limi...
Definition
random.h:85
streams.h
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