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137 lines
3.4 KiB
C++
137 lines
3.4 KiB
C++
/**
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* Copyright (c) 2017, Timothy Stack
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* * Neither the name of Timothy Stack nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* @file big_array.hh
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*/
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#ifndef lnav_big_array_hh
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#define lnav_big_array_hh
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#include <sys/mman.h>
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#include <unistd.h>
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#include "base/math_util.hh"
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template<typename T>
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struct big_array {
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static const size_t DEFAULT_INCREMENT = 100 * 1000;
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big_array()
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: ba_ptr(nullptr), ba_size(0), ba_capacity(0){
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};
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bool reserve(size_t size)
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{
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if (size < this->ba_capacity) {
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return false;
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}
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if (this->ba_ptr) {
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munmap(this->ba_ptr,
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roundup_size(this->ba_capacity * sizeof(T), getpagesize()));
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}
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this->ba_capacity = size + DEFAULT_INCREMENT;
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void* result
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= mmap(nullptr,
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roundup_size(this->ba_capacity * sizeof(T), getpagesize()),
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PROT_READ | PROT_WRITE,
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MAP_ANONYMOUS | MAP_PRIVATE,
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-1,
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0);
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ensure(result != MAP_FAILED);
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this->ba_ptr = (T*) result;
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return true;
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};
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void clear()
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{
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this->ba_size = 0;
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};
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size_t size() const
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{
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return this->ba_size;
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};
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void shrink_to(size_t new_size)
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{
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require(new_size <= this->ba_size);
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this->ba_size = new_size;
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}
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bool empty() const
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{
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return this->ba_size == 0;
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};
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void push_back(const T& val)
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{
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this->ba_ptr[this->ba_size] = val;
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this->ba_size += 1;
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};
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T& operator[](size_t index)
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{
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return this->ba_ptr[index];
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};
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const T& operator[](size_t index) const
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{
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return this->ba_ptr[index];
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};
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T& back()
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{
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return this->ba_ptr[this->ba_size - 1];
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}
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typedef T* iterator;
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iterator begin()
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{
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return this->ba_ptr;
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};
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iterator end()
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{
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return this->ba_ptr + this->ba_size;
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};
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T* ba_ptr;
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size_t ba_size;
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size_t ba_capacity;
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};
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#endif
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