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fixed strict-alliasing warning

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This commit is contained in:
Oleksandr Masliuchenko 2017-04-22 16:00:23 +03:00
parent cb95e0307b
commit 5317dd77d4
1 changed files with 29 additions and 5 deletions
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34
Adafruit_GFX.cpp
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@ -70,6 +70,30 @@ POSSIBILITY OF SUCH DAMAGE.
#define _swap_int16_t(a, b) { int16_t t = a; a = b; b = t; }
#endif
inline GFXglyph * pgm_read_glyph_ptr(const GFXfont *gfxFont, uint8_t c)
{
#ifdef __AVR__
return &(((GFXglyph *)pgm_read_pointer(&gfxFont->glyph))[c]);
#else
// expression in __AVR__ section may generate "dereferencing type-punned pointer will break strict-aliasing rules" warning
// In fact, on other platforms (such as STM32) there is no need to do this pointer magic as program memory may be read in a usual way
// So expression may be simplified
return gfxFont->glyph + c;
#endif //__AVR__
}
inline uint8_t * pgm_read_bitmap_ptr(const GFXfont *gfxFont)
{
#ifdef __AVR__
return (uint8_t *)pgm_read_pointer(&gfxFont->bitmap);
#else
// expression in __AVR__ section generates "dereferencing type-punned pointer will break strict-aliasing rules" warning
// In fact, on other platforms (such as STM32) there is no need to do this pointer magic as program memory may be read in a usual way
// So expression may be simplified
return gfxFont->bitmap;
#endif //__AVR__
}
Adafruit_GFX::Adafruit_GFX(int16_t w, int16_t h):
WIDTH(w), HEIGHT(h)
{
@ -594,8 +618,8 @@ void Adafruit_GFX::drawChar(int16_t x, int16_t y, unsigned char c,
// directly with 'bad' characters of font may cause mayhem!
c -= pgm_read_byte(&gfxFont->first);
GFXglyph *glyph = &(((GFXglyph *)pgm_read_pointer(&gfxFont->glyph))[c]);
uint8_t *bitmap = (uint8_t *)pgm_read_pointer(&gfxFont->bitmap);
GFXglyph *glyph = pgm_read_glyph_ptr(gfxFont, c);
uint8_t *bitmap = pgm_read_bitmap_ptr(gfxFont);
uint16_t bo = pgm_read_word(&glyph->bitmapOffset);
uint8_t w = pgm_read_byte(&glyph->width),
@ -680,7 +704,7 @@ void Adafruit_GFX::write(uint8_t c) {
uint8_t first = pgm_read_byte(&gfxFont->first);
if((c >= first) && (c <= (uint8_t)pgm_read_byte(&gfxFont->last))) {
uint8_t c2 = c - pgm_read_byte(&gfxFont->first);
GFXglyph *glyph = &(((GFXglyph *)pgm_read_pointer(&gfxFont->glyph))[c2]);
GFXglyph *glyph = pgm_read_glyph_ptr(gfxFont, c2);
uint8_t w = pgm_read_byte(&glyph->width),
h = pgm_read_byte(&glyph->height);
if((w > 0) && (h > 0)) { // Is there an associated bitmap?
@ -806,7 +830,7 @@ void Adafruit_GFX::getTextBounds(char *str, int16_t x, int16_t y,
if(c != '\r') { // Not a carriage return, is normal char
if((c >= first) && (c <= last)) { // Char present in current font
c -= first;
glyph = &(((GFXglyph *)pgm_read_pointer(&gfxFont->glyph))[c]);
glyph = pgm_read_glyph_ptr(gfxFont, c);
gw = pgm_read_byte(&glyph->width);
gh = pgm_read_byte(&glyph->height);
xa = pgm_read_byte(&glyph->xAdvance);
@ -896,7 +920,7 @@ void Adafruit_GFX::getTextBounds(const __FlashStringHelper *str,
if(c != '\r') { // Not a carriage return, is normal char
if((c >= first) && (c <= last)) { // Char present in current font
c -= first;
glyph = &(((GFXglyph *)pgm_read_pointer(&gfxFont->glyph))[c]);
glyph = pgm_read_glyph_ptr(gfxFont, c);
gw = pgm_read_byte(&glyph->width);
gh = pgm_read_byte(&glyph->height);
xa = pgm_read_byte(&glyph->xAdvance);