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Update IO_HALDisplay.h

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Check for memory allocation errors.
This commit is contained in:
Neil McKechnie 2023-02-25 11:43:05 +00:00
parent 711ad6f030
commit 8c8a913678
1 changed files with 16 additions and 4 deletions
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20
IO_HALDisplay.h
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@ -76,6 +76,7 @@ private:
uint8_t *_lastRowGeneration = NULL;
uint8_t _rowNoToScreen = 0;
uint8_t _charPosToScreen = 0;
bool _startAgain = false;
DisplayInterface *_nextDisplay = NULL;
public:
@ -91,6 +92,7 @@ protected:
// Constructor
HALDisplay(uint8_t displayNo, I2CAddress i2cAddress, int width, int height) {
_displayDriver = new T(i2cAddress, width, height);
if (!_displayDriver) return; // Check for memory allocation failure
_I2CAddress = i2cAddress;
_width = width;
_height = height;
@ -101,8 +103,12 @@ protected:
// Allocate arrays
_buffer = (char *)calloc(_numRows*_numCols, sizeof(char));
if (!_buffer) return; // Check for memory allocation failure
_rowGeneration = (uint8_t *)calloc(_numRows, sizeof(uint8_t));
if (!_rowGeneration) return; // Check for memory allocation failure
_lastRowGeneration = (uint8_t *)calloc(_numRows, sizeof(uint8_t));
if (!_lastRowGeneration) return; // Check for memory allocation failure
// Fill buffer with spaces
memset(_buffer, ' ', _numCols*_numRows);
@ -116,7 +122,7 @@ protected:
// Also add this display to list of display handlers
DisplayInterface::addDisplay(displayNo);
// Is this the main display?
// Is this the system display (0)?
if (displayNo == 0) {
// Set first two lines on screen
this->setRow(displayNo, 0);
@ -135,13 +141,15 @@ protected:
// to the screen until that row has been refreshed.
// First check if the OLED driver is still busy from a previous
// call. If so, don't to anything until the next entry.
// call. If so, don't do anything until the next entry.
if (!_displayDriver->isBusy()) {
// Check if we've just done the end of a row
if (_charPosToScreen >= _numCols) {
// Move to next line
if (++_rowNoToScreen >= _numRows)
if (++_rowNoToScreen >= _numRows || _startAgain) {
_rowNoToScreen = 0; // Wrap to first row
_startAgain = false;
}
if (_rowGeneration[_rowNoToScreen] != _lastRowGeneration[_rowNoToScreen]) {
// Row content has changed, so start outputting it
@ -222,10 +230,14 @@ public:
for (_colNo = 0; _colNo < _numCols; _colNo++)
_buffer[_rowNo*_numCols+_colNo] = ' ';
_colNo = 0;
// Mark that the buffer has been touched. It will be
// Mark that the buffer has been touched. It will start being
// sent to the screen on the next loop entry, by which time
// the line should have been written to the buffer.
_rowGeneration[_rowNo]++;
// Indicate that the output loop is to start updating the screen again from
// row 0. Otherwise, on a full screen rewrite the bottom part may be drawn
// before the top part!
_startAgain = true;
}
// Write one character to the screen referenced in the last setRow() call.