arduino-esp32/cores/esp32/cbuf.cpp

197 lines
4.7 KiB
C++

/*
cbuf.cpp - Circular buffer implementation
Copyright (c) 2014 Ivan Grokhotkov. All rights reserved.
This file is part of the esp8266 core for Arduino environment.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "cbuf.h"
cbuf::cbuf(size_t size) :
next(NULL), _size(size+1), _buf(new char[size+1]), _bufend(_buf + size + 1), _begin(_buf), _end(_begin)
{
}
cbuf::~cbuf()
{
delete[] _buf;
}
size_t cbuf::resizeAdd(size_t addSize)
{
return resize(_size + addSize);
}
size_t cbuf::resize(size_t newSize)
{
size_t bytes_available = available();
newSize += 1;
// not lose any data
// if data can be lost use remove or flush before resize
if((newSize < bytes_available) || (newSize == _size)) {
return _size;
}
char *newbuf = new char[newSize];
char *oldbuf = _buf;
if(!newbuf) {
return _size;
}
if(_buf) {
read(newbuf, bytes_available);
memset((newbuf + bytes_available), 0x00, (newSize - bytes_available));
}
_begin = newbuf;
_end = newbuf + bytes_available;
_bufend = newbuf + newSize;
_size = newSize;
_buf = newbuf;
delete[] oldbuf;
return _size;
}
size_t cbuf::available() const
{
if(_end >= _begin) {
return _end - _begin;
}
return _size - (_begin - _end);
}
size_t cbuf::size()
{
return _size;
}
size_t cbuf::room() const
{
if(_end >= _begin) {
return _size - (_end - _begin) - 1;
}
return _begin - _end - 1;
}
int cbuf::peek()
{
if(empty()) {
return -1;
}
return static_cast<int>(*_begin);
}
size_t cbuf::peek(char *dst, size_t size)
{
size_t bytes_available = available();
size_t size_to_read = (size < bytes_available) ? size : bytes_available;
size_t size_read = size_to_read;
char * begin = _begin;
if(_end < _begin && size_to_read > (size_t) (_bufend - _begin)) {
size_t top_size = _bufend - _begin;
memcpy(dst, _begin, top_size);
begin = _buf;
size_to_read -= top_size;
dst += top_size;
}
memcpy(dst, begin, size_to_read);
return size_read;
}
int cbuf::read()
{
if(empty()) {
return -1;
}
char result = *_begin;
_begin = wrap_if_bufend(_begin + 1);
return static_cast<int>(result);
}
size_t cbuf::read(char* dst, size_t size)
{
size_t bytes_available = available();
size_t size_to_read = (size < bytes_available) ? size : bytes_available;
size_t size_read = size_to_read;
if(_end < _begin && size_to_read > (size_t) (_bufend - _begin)) {
size_t top_size = _bufend - _begin;
memcpy(dst, _begin, top_size);
_begin = _buf;
size_to_read -= top_size;
dst += top_size;
}
memcpy(dst, _begin, size_to_read);
_begin = wrap_if_bufend(_begin + size_to_read);
return size_read;
}
size_t cbuf::write(char c)
{
if(full()) {
return 0;
}
*_end = c;
_end = wrap_if_bufend(_end + 1);
return 1;
}
size_t cbuf::write(const char* src, size_t size)
{
size_t bytes_available = room();
size_t size_to_write = (size < bytes_available) ? size : bytes_available;
size_t size_written = size_to_write;
if(_end >= _begin && size_to_write > (size_t) (_bufend - _end)) {
size_t top_size = _bufend - _end;
memcpy(_end, src, top_size);
_end = _buf;
size_to_write -= top_size;
src += top_size;
}
memcpy(_end, src, size_to_write);
_end = wrap_if_bufend(_end + size_to_write);
return size_written;
}
void cbuf::flush()
{
_begin = _buf;
_end = _buf;
}
size_t cbuf::remove(size_t size)
{
size_t bytes_available = available();
if(size >= bytes_available) {
flush();
return 0;
}
size_t size_to_remove = (size < bytes_available) ? size : bytes_available;
if(_end < _begin && size_to_remove > (size_t) (_bufend - _begin)) {
size_t top_size = _bufend - _begin;
_begin = _buf;
size_to_remove -= top_size;
}
_begin = wrap_if_bufend(_begin + size_to_remove);
return available();
}