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CommandStation-EX/MemStream.cpp
2020-07-16 14:04:59 +01:00

99 lines
2.4 KiB
C++

/*
(c) 2015 Ingo Fischer
buffer serial device
based on Arduino SoftwareSerial
Constructor warning messages fixed by Chris Harlow.
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 "MemStream.h"
MemStream::MemStream(uint8_t *buffer, const uint16_t len, uint16_t content_len, bool allowWrite)
:_buffer(buffer),_len(len), _buffer_overflow(false), _pos_read(0), _allowWrite(allowWrite)
{
if (content_len==0) memset(_buffer, 0, _len);
_pos_write=(content_len>len)? len: content_len;
}
size_t MemStream::write(uint8_t byte) {
if (! _allowWrite) return -1;
if (_pos_write >= _len) {
_buffer_overflow = true;
return 0;
}
_buffer[_pos_write] = byte;
++_pos_write;
return 1;
}
void MemStream::flush() {
memset(_buffer, 0, _len);
_pos_write = 0;
_pos_read = 0;
}
int MemStream::read() {
if (_pos_read >= _len) {
_buffer_overflow = true;
return -1;
}
if (_pos_read >= _pos_write) {
return -1;
}
return _buffer[_pos_read++];
}
int MemStream::peek() {
if (_pos_read >= _len) {
_buffer_overflow = true;
return -1;
}
if (_pos_read >= _pos_write) {
return -1;
}
return _buffer[_pos_read+1];
}
int MemStream::available() {
int ret=_pos_write-_pos_read;
if (ret<0) ret=0;
return ret;
}
void MemStream::setBufferContent(uint8_t *buffer, uint16_t content_len) {
memset(_buffer, 0, _len);
memcpy(_buffer, buffer, content_len);
_buffer_overflow=false;
_pos_write=content_len;
_pos_read=0;
}
void MemStream::setBufferContentFromProgmem(uint8_t *buffer, uint16_t content_len) {
memset(_buffer, 0, _len);
memcpy_P(_buffer, buffer, content_len);
_buffer_overflow=false;
_pos_write=content_len;
_pos_read=0;
}
void MemStream::setBufferContentPosition(uint16_t read_pos, uint16_t write_pos) {
_pos_write=write_pos;
_pos_read=read_pos;
}