arduino-esp32/cores/esp32/StreamString.cpp
Earle F. Philhower, III ab309e40d5 Copy ESP8266 String w/SSO to ESP32 repo (#2715)
I redid the ESP8266 WString library to enable small string optimization
(SSO) a while back, and think it would be helpful even on the ESP32 with
its higher memory complement.

SSO avoids lots of tiny mallocs() on the heap which cause fragmentation
by using the memory in the class object itself to store the actual
string and only mallocing() for buffers that are larger than what can
fit in thie class object.  Modern C++ std::string implementations have
this optimization as well, but since we're using Arduino strings we had
to roll our own.
2019-04-26 19:41:42 +03:00

67 lines
1.7 KiB
C++

/**
StreamString.cpp
Copyright (c) 2015 Markus Sattler. 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 <Arduino.h>
#include "StreamString.h"
size_t StreamString::write(const uint8_t *data, size_t size) {
if(size && data) {
if(reserve(length() + size + 1)) {
memcpy((void *) (wbuffer() + len()), (const void *) data, size);
setLen(len() + size);
*(wbuffer() + len()) = 0x00; // add null for string end
return size;
}
}
return 0;
}
size_t StreamString::write(uint8_t data) {
return concat((char) data);
}
int StreamString::available() {
return length();
}
int StreamString::read() {
if(length()) {
char c = charAt(0);
remove(0, 1);
return c;
}
return -1;
}
int StreamString::peek() {
if(length()) {
char c = charAt(0);
return c;
}
return -1;
}
void StreamString::flush() {
}