libreoffice-online/net/Buffer.hpp
Michael Meeks 7183a3d3de spdx: improve machine and human readability of headers.
Change-Id: Ice934380029bf27054e830fffc07a5d037d1430f
Signed-off-by: Michael Meeks <michael.meeks@collabora.com>
2023-11-14 19:36:31 +00:00

136 lines
3.6 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
/*
* Copyright the Collabora Online contributors.
*
* SPDX-License-Identifier: MPL-2.0
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#pragma once
#include <assert.h>
#include <ostream>
#include <vector>
#include <Util.hpp>
// Blocks -> we can share from client -> server ... etc.
// headers / and a 'writeV' etc. =)
/**
* Encapsulate data we need to write.
*/
class Buffer
{
std::size_t _offset; /// offset into _buffer of data
std::vector<char> _buffer;
public:
Buffer() : _offset(0)
{
}
typedef std::vector<char>::iterator iterator;
typedef std::vector<char>::const_iterator const_iterator;
std::size_t size() const { return _buffer.size() - _offset; }
bool empty() const { return _offset == _buffer.size(); }
const char *getBlock() const
{
if (!empty())
return &_buffer[_offset];
return nullptr;
}
std::size_t getBlockSize() const
{
return size();
}
void eraseFirst(std::size_t len)
{
if (len <= 0)
return;
assert(_offset + len <= _buffer.size());
assert(_offset + size() == _buffer.size());
len = std::min(len, size()); // Avoid accidental damage.
// avoid regular shuffling down larger chunks of data
if (_buffer.size() > 16384 && // lots of queued data
len < size() && // not a complete erase
_offset < 16384 * 64 && // do cleanup a Mb at a time or so:
size() > 512) // early cleanup if what remains is small.
{
_offset += len;
return;
}
_buffer.erase(_buffer.begin(), _buffer.begin() + _offset + len);
_offset = 0;
}
void append(const char *data, const int len)
{
_buffer.insert(_buffer.end(), data, data + len);
}
void append(const std::string& s) { append(s.c_str(), s.size()); }
/// Append a literal string, with compile-time size capturing.
template <std::size_t N> void append(const char (&s)[N])
{
static_assert(N > 1, "Cannot append empty strings.");
append(s, N - 1); // Minus null termination.
}
void dumpHex(std::ostream &os, const char *legend, const char *prefix) const
{
if (size() > 0 || _offset > 0)
os << prefix << "Buffer size: " << size() << " offset: " << _offset << '\n';
if (_buffer.size() > 0)
Util::dumpHex(os, _buffer, legend, prefix);
}
// various std::vector API compatibility functions
void clear()
{
_buffer.clear();
_offset = 0;
}
iterator begin() { return _buffer.begin() + _offset; }
const_iterator begin() const { return _buffer.begin() + _offset; }
iterator end() { return _buffer.end(); }
const_iterator end() const { return _buffer.end(); }
char operator[](int index) const { return _buffer[_offset + index]; }
char& operator[](int index) { return _buffer[_offset + index]; }
const char* data() const { return _buffer.data() + _offset; }
char* data() { return _buffer.data() + _offset; }
iterator erase(iterator first, iterator last)
{
if (first == begin())
{
eraseFirst(last - begin());
return begin();
}
iterator ret = _buffer.erase(first, last);
return ret;
}
};
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */