Make some operators in IPAddress const

[matthijskooijman]

These functions do not modify the IPAddress object, but were not marked
as const. This meant that you could not do:

void set_ip(const IPAddress& ip) {
this->ip = ip;
}

Since calling operator uint32_t() on ip would discard the constness of
the reference.

[cmaglie]

Applying const to methods is good, but for some reason it breaks the AdvancedChatExample, may you check that?

May you also apply the patch to the SAM core?

[matthijskooijman]

What example do you mean exactly? I tried the AdvancedChatServer example, which compiles normally (though it seems to use too much memory when for the Arduino Ethernet, but that's also without my patch applied).

What board are you using? What error are you seeing?

[cmaglie]

Yes the example is AdvancedChatServer, I'm compiling for Arduino Uno, it gives:

Arduino: 0155 (Linux), Board: "Arduino Uno"

Using library SPI in folder: /home/megabug/git/arduino/build/linux/work/hardware/arduino/avr/libraries/SPI (legacy)
Using library Ethernet in folder: /home/megabug/git/arduino/build/linux/work/libraries/Ethernet 

[...cut...]

/home/megabug/git/arduino/build/linux/work/hardware/tools/avr/bin/avr-g++ -c -g -Os -w -fno-exceptions -ffunction-sections -fdata-sections -MMD -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=155 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR -I/home/megabug/git/arduino/build/linux/work/hardware/arduino/avr/cores/arduino -I/home/megabug/git/arduino/build/linux/work/hardware/arduino/avr/variants/standard /home/megabug/git/arduino/build/linux/work/hardware/arduino/avr/cores/arduino/IPAddress.cpp -o /tmp/build4145119589917473324.tmp/IPAddress.cpp.o 
/home/megabug/git/arduino/build/linux/work/hardware/arduino/avr/cores/arduino/IPAddress.cpp:40: error: prototype for ‘bool IPAddress::operator==(const uint8_t*)’ does not match any in class ‘IPAddress’
/home/megabug/git/arduino/build/linux/work/hardware/arduino/avr/cores/arduino/IPAddress.h:54: error: candidates are: bool IPAddress::operator==(const uint8_t*) const
/home/megabug/git/arduino/build/linux/work/hardware/arduino/avr/cores/arduino/IPAddress.h:53: error:                 bool IPAddress::operator==(const IPAddress&) const

Maybe you should add the "const" on the operator== implementation in IPAddress.cpp

[matthijskooijman]

Yeah I should, I'm almost certain that's the problem.

I also realized why I couldn't reproduce it: The build/linux/work/hardware directory still had the core files from the last time I ran "ant", I didn't realize that I did a "regular" build that copies those files instead of symlinks a while ago.

I'll push an updated patch with both things fixed in a minute, thanks for having a look.

[matthijskooijman]

Here's the update. Also tested the AdvancedChatServer example for the Due.