All the while() loops that check for the SPI transfer to be complete have the
semi-colon immediately after the closing parenthesis. This both causes a
compiler warning of "warning: suggest a space before ';' or explicit braces
around empty body in 'while' statement", and is considered a less-than-ideal
programming practice. This patch breaks the semi-colon on to the next line,
both eliminating the compiler error and making the code more readable.
In all probability the test should be moved into a macro or a inlineable
sub-routine.
In C++, true and false are language keywords, so there is no need to
define them as macros. Including stdbool.h in C++ effectively changes
nothing. In C, true, false and also the bool type are not available, but
including stdbool.h will make them available.
Using stdbool.h means that we get true, false and the bool type in
whatever way the compiler thinks is best, which seems like a good idea
to me.
This also fixes the following compiler warnings if a .c file includes
both stdbool.h and Arduino.h:
warning: "true" redefined [enabled by default]
#define true 0x1
warning: "false" redefined [enabled by default]
#define false 0x0
This fixes#1570 and helps toward fixing #1728.
This only changed the AVR core, the SAM core already doesn't define true
and false (but doesn't include stdbool.h either).
Previously, pointer casting was used, but this resulted in strict-aliasing warnings:
IPAddress.h: In member function ‘IPAddress::operator uint32_t() const’:
IPAddress.h:46:61: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
operator uint32_t() const { return *((uint32_t*)_address); };
^
IPAddress.h: In member function ‘bool IPAddress::operator==(const IPAddress&) const’:
IPAddress.h:47:81: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
bool operator==(const IPAddress& addr) const { return (*((uint32_t*)_address)) == (*((uint32_t*)addr._address)); };
^
IPAddress.h:47:114: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
bool operator==(const IPAddress& addr) const { return (*((uint32_t*)_address)) == (*((uint32_t*)addr._address)); };
Converting between unrelated types like this is commonly done using a union,
which do not break the strict-aliasing rules. Using that union, inside
IPAddress there is now an attribute _address.bytes for the raw byte
arra, or _address.dword for the uint32_t version.
Since we now have easy access to the uint32_t version, this also removes
two memcpy invocations that can just become assignments.
This patch does not change the generated code in any way, the compiler
already optimized away the memcpy calls and the previous casts mean
exactly the same.
This is a different implementation of a part of #1399 and it helps
toward fixing #1728.
EthernetClass is a friend class of IPAddress, so it is allowed to use
its _address attribute directly. However, it should be using
IPAddress::raw_address() instead, like all the other friend classes do.
This changes allows changing the _address attribute to fix some warnings
next.
The index attributes have been uint8_t for a while, so there is no point
in using int for local variables. This should allow the compiler to
generate slightly more efficient code, but (at least on gcc 4.8.2) it
also confuses the register allocator, causing this change to increase
code size by 2 bytes instead due to extra push/pop instructions (but
this will probably change in the future if the compiler improves).
Switch the tx and rx buffer head/tail entries in the HardwareSerial
initialisation list so that they match the order the fields are defined
in. This fixes a compiler warning (repeated for each of the
HardwareSerial source files the header is used in).
