1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
|
/**
* Copyright (c) 2017, Timothy Stack
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of Timothy Stack nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @file big_array.hh
*/
#ifndef lnav_big_array_hh
#define lnav_big_array_hh
#include <sys/mman.h>
#include <unistd.h>
#include "base/lnav_log.hh"
#include "base/math_util.hh"
template<typename T>
struct big_array {
static const size_t DEFAULT_INCREMENT = 100 * 1000;
bool reserve(size_t size)
{
if (size < this->ba_capacity) {
return false;
}
if (this->ba_ptr) {
munmap(this->ba_ptr,
roundup_size(this->ba_capacity * sizeof(T), getpagesize()));
}
this->ba_capacity = size + DEFAULT_INCREMENT;
void* result
= mmap(nullptr,
roundup_size(this->ba_capacity * sizeof(T), getpagesize()),
PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE,
-1,
0);
ensure(result != MAP_FAILED);
this->ba_ptr = (T*) result;
return true;
}
void clear() { this->ba_size = 0; }
size_t size() const { return this->ba_size; }
void shrink_to(size_t new_size)
{
require(new_size <= this->ba_size);
this->ba_size = new_size;
}
bool empty() const { return this->ba_size == 0; }
void push_back(const T& val)
{
this->ba_ptr[this->ba_size] = val;
this->ba_size += 1;
}
T& operator[](size_t index) { return this->ba_ptr[index]; }
const T& operator[](size_t index) const { return this->ba_ptr[index]; }
T& back() { return this->ba_ptr[this->ba_size - 1]; }
using iterator = T*;
iterator begin() { return this->ba_ptr; }
iterator end() { return this->ba_ptr + this->ba_size; }
T* ba_ptr{nullptr};
size_t ba_size{0};
size_t ba_capacity{0};
};
#endif
|
