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121 lines (107 loc) · 2.71 KB
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#ifndef COMMON_UTILITY_H
#define COMMON_UTILITY_H
#include <iostream>
#include <vector>
#include <iterator>
#include <type_traits>
#include <numeric>
#include <random>
#include <algorithm>
#include <cassert>
#include <sys/uio.h>
#include "common/pointer_cast.h"
namespace lseb {
template<typename T>
class Buffer {
public:
using value_type = T;
using iterator = T*;
using const_iterator = T const*;
private:
iterator m_begin;
iterator m_end;
iterator m_next_read;
iterator m_next_write;
public:
Buffer(void* begin, void* end)
:
m_begin(pointer_cast<T>(begin)),
m_end(pointer_cast<T>(end)),
m_next_read(pointer_cast<T>(begin)),
m_next_write(pointer_cast<T>(begin)) {
assert(m_begin < m_end);
}
Buffer(iterator begin, iterator end)
:
m_begin(begin),
m_end(end),
m_next_read(begin),
m_next_write(begin) {
assert(m_begin < m_end);
}
Buffer(const_iterator begin, const_iterator end)
:
m_begin(const_cast<iterator>(begin)),
m_end(const_cast<iterator>(end)),
m_next_read(const_cast<iterator>(begin)),
m_next_write(const_cast<iterator>(begin)) {
assert(m_begin < m_end);
}
iterator begin() {
return m_begin;
}
iterator end() {
return m_end;
}
iterator next_read() {
return m_next_read;
}
iterator next_write() {
return m_next_write;
}
size_t size() {
return std::distance(m_begin, m_end);
}
size_t ready() {
return (size() + std::distance(m_next_read, m_next_write)) % size();
}
size_t available() {
return size() - ready();
}
void release(size_t n) {
assert(ready() >= n);
m_next_read = m_begin + (m_next_read - m_begin + n) % size();
}
void reserve(size_t n) {
assert(available() > n);
m_next_write = m_begin + (m_next_write - m_begin + n) % size();
}
};
// http://stackoverflow.com/questions/6942273/get-random-element-from-container-c-stl
template<typename Iter>
Iter select_randomly(Iter start, Iter end) {
static std::random_device rd;
static std::mt19937 gen(rd());
std::uniform_int_distribution<> dis(0, std::distance(start, end) - 1);
return std::next(start, dis(gen));
}
inline size_t iovec_length(std::vector<iovec> const& iov) {
return std::accumulate(
std::begin(iov),
std::end(iov),
0,
[](size_t partial, iovec const& v) {
return partial + v.iov_len;});
}
inline std::vector<int> create_sequence(int id, int total) {
int first_id = (id != total - 1) ? id + 1 : 0;
std::vector<int> sequence(total);
std::iota(std::begin(sequence), std::end(sequence), 0);
std::rotate(
std::begin(sequence),
std::begin(sequence) + first_id,
std::end(sequence));
return sequence;
}
}
#endif