Added __FlashStringhelper* comparison operators to String object #2264
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| @@ -453,6 +453,19 @@ unsigned char String::equals(const char *cstr) const | |||
| return strcmp(buffer, cstr) == 0; | |||
| } | |||
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| unsigned char String::equals(const __FlashStringHelper *fstr) const | |||
| { | |||
| const char PROGMEM *p = (const char PROGMEM *)fstr; | |||
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Shouldn't you be using reinterpret_cast here? Please see: #1770.
Note that PGM_P macro should be used for compatible with older version of avr-libc. Please see: 98777e8#diff-0 and ffddfc8.
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In this case PROGMEM/PGM_P is not needed at all, like in #1770.
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@dvdfreitag, May you provide a test sketch that demonstrates the new functionality? |
Something really basic (so basic it looks pointless), String toCompare = "Hello World!";
void setup() {
Serial.begin(9600);
Serial.println(hello == F("Hello World!"));
}
void loop() { }Should always print 1. A more advanced use case could be reading a string from Serial (or SPI, I2C etc..) and then comparing that string to a string stored in flash. |
Without this check the comparison of the String "Hello World!" and the flash String "Hello World!something" would return 1.
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@ArduinoBot build this please |
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Merged build finished. Test FAILed. |
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Build failed. |
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Sorry for scheduling the PR builder. It works only on PRs against branch ide-1.5.x |
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@dvdfreitag String hello = "Hello";
void setup() {
hello += " World!";
Serial.begin(9600);
Serial.println(hello == F("Hello"));
Serial.println(hello == F(" World!"));
Serial.println(hello == F("Hello World!"));
Serial.println(hello == F("BLAH"));
}
void loop() {
}and the result is: as expected. May you provide an example with all the details to reproduce the issue? |
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@cmaglie String toCompare = "Hello World!";
void setup() {
Serial.begin(9600);
Serial.println(toCompare == F("Hello World!123"));
}
void loop() { }This sketch would produce a 1 since the original for loop only compares up to the null terminator in the String. The added check just ensures that they are both terminated in the same location. |
Mmm, have you actually tested it? |
Yes, using IDE 1.0.5-r2 that sketch prints |
Sorry for the delay, yes, it appears that you are correct. This bug is present in 1.0.5-r2, but not in the |
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