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protect ringstream

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This commit is contained in:
Harald Barth 2021-11-06 23:51:32 +01:00
parent d7e46ac625
commit 55c7a0a1e8
2 changed files with 18 additions and 1 deletions
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14
RingStream.cpp
View File

@ -30,28 +30,36 @@ RingStream::RingStream( const uint16_t len)
_overflow=false;
_mark=0;
_count=0;
#if defined(ARDUINO_ARCH_ESP32)
portMUX_TYPE _bufMux = portMUX_INITIALIZER_UNLOCKED;
#endif
}
size_t RingStream::write(uint8_t b) {
if (_overflow) return 0;
portENTER_CRITICAL(&_bufMux);
_buffer[_pos_write] = b;
++_pos_write;
if (_pos_write==_len) _pos_write=0;
if (_pos_write==_pos_read) {
_overflow=true;
portEXIT_CRITICAL(&_bufMux);
return 0;
}
_count++;
portEXIT_CRITICAL(&_bufMux);
return 1;
}
int RingStream::read(byte advance) {
if ((_pos_read==_pos_write) && !_overflow) return -1; // empty
if (_pos_read == _mark) return -1;
portENTER_CRITICAL(&_bufMux);
byte b=_buffer[_pos_read];
_pos_read += advance;
if (_pos_read==_len) _pos_read=0;
_overflow=false;
portEXIT_CRITICAL(&_bufMux);
return b;
}
@ -70,11 +78,13 @@ int RingStream::freeSpace() {
// mark start of message with client id (0...9)
void RingStream::mark(uint8_t b) {
//DIAG(F("Mark1 len=%d count=%d pr=%d pw=%d m=%d"),_len, _count,_pos_read,_pos_write,_mark);
portENTER_CRITICAL(&_bufMux);
_mark=_pos_write;
write(b); // client id
write((uint8_t)0); // count MSB placemarker
write((uint8_t)0); // count LSB placemarker
_count=0;
portEXIT_CRITICAL(&_bufMux);
}
// peekTargetMark is used by the parser stash routines to know which client
@ -89,16 +99,19 @@ void RingStream::info() {
bool RingStream::commit() {
//DIAG(F("Commit1 len=%d count=%d pr=%d pw=%d m=%d"),_len, _count,_pos_read,_pos_write,_mark);
portENTER_CRITICAL(&_bufMux);
if (_overflow) {
DIAG(F("RingStream(%d) commit(%d) OVERFLOW"),_len, _count);
// just throw it away
_pos_write=_mark;
_overflow=false;
portEXIT_CRITICAL(&_bufMux);
return false; // commit failed
}
if (_count==0) {
// ignore empty response
_pos_write=_mark;
portEXIT_CRITICAL(&_bufMux);
return true; // true=commit ok
}
// Go back to the _mark and inject the count 1 byte later
@ -110,5 +123,6 @@ bool RingStream::commit() {
_buffer[_mark]=lowByte(_count);
_mark=_len+1;
//DIAG(F("Commit2 len=%d count=%d pr=%d pw=%d m=%d"),_len, _count,_pos_read,_pos_write,_mark);
portEXIT_CRITICAL(&_bufMux);
return true; // commit worked
}

3
RingStream.h
View File

@ -46,6 +46,9 @@ class RingStream : public Print {
int _mark;
int _count;
byte * _buffer;
#if defined(ARDUINO_ARCH_ESP32)
portMUX_TYPE _bufMux;
#endif
};
#endif