126 lines
3.9 KiB
C++
126 lines
3.9 KiB
C++
#ifndef OSMIUM_UTIL_DELTA_HPP
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#define OSMIUM_UTIL_DELTA_HPP
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/*
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This file is part of Osmium (http://osmcode.org/libosmium).
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Copyright 2013-2017 Jochen Topf <jochen@topf.org> and others (see README).
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Boost Software License - Version 1.0 - August 17th, 2003
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Permission is hereby granted, free of charge, to any person or organization
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obtaining a copy of the software and accompanying documentation covered by
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this license (the "Software") to use, reproduce, display, distribute,
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execute, and transmit the Software, and to prepare derivative works of the
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Software, and to permit third-parties to whom the Software is furnished to
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do so, all subject to the following:
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The copyright notices in the Software and this entire statement, including
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the above license grant, this restriction and the following disclaimer,
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must be included in all copies of the Software, in whole or in part, and
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all derivative works of the Software, unless such copies or derivative
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works are solely in the form of machine-executable object code generated by
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a source language processor.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
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SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
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FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
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ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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DEALINGS IN THE SOFTWARE.
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*/
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#include <cstdint>
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#include <type_traits>
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#include <utility>
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#include <osmium/util/cast.hpp>
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namespace osmium {
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namespace util {
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/**
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* Helper class for delta encoding.
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*/
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template <typename TValue, typename TDelta = int64_t>
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class DeltaEncode {
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static_assert(std::is_integral<TValue>::value,
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"DeltaEncode value type must be some integer");
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static_assert(std::is_integral<TDelta>::value && std::is_signed<TDelta>::value,
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"DeltaEncode delta type must be some signed integer");
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TValue m_value;
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public:
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using value_type = TValue;
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using delta_type = TDelta;
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explicit DeltaEncode(TValue value = 0) :
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m_value(value) {
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}
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void clear() noexcept {
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m_value = 0;
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}
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TValue value() const noexcept {
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return m_value;
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}
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TDelta update(TValue new_value) noexcept {
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using std::swap;
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swap(m_value, new_value);
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return static_cast_with_assert<TDelta>(m_value) -
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static_cast_with_assert<TDelta>(new_value);
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}
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}; // class DeltaEncode
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/**
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* Helper class for delta decoding.
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*/
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template <typename TValue, typename TDelta = int64_t>
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class DeltaDecode {
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static_assert(std::is_integral<TValue>::value,
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"DeltaDecode value type must be some integer");
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static_assert(std::is_integral<TDelta>::value && std::is_signed<TDelta>::value,
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"DeltaDecode delta type must be some signed integer");
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TValue m_value;
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public:
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using value_type = TValue;
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using delta_type = TDelta;
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DeltaDecode() :
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m_value(0) {
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}
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void clear() noexcept {
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m_value = 0;
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}
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TValue update(TDelta delta) noexcept {
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m_value = static_cast_with_assert<TValue>(
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static_cast_with_assert<TDelta>(m_value) + delta);
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return m_value;
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}
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}; // class DeltaDecode
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} // namespace util
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} // namespace osmium
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#endif // OSMIUM_UTIL_DELTA_HPP
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