This can be used to check whether untrusted sizes would cause overflow
when used to calculate how much memory is needed.
Signed-off-by: Simon McVittie <smcv@collabora.com>
Case fallthrough warnings can be suppressed using the __fallthrough__
compiler attribute. Unfortunately, not all compilers have this
attribute, or even have __has_attribute to check if they have the
__fallthrough__ attribute. [[fallthrough]] is also available in C++17
and the next C2x, but not everyone uses C++17 or C2x.
So define the SDL_FALLTHROUGH macro to deal with those problems - if we
are using C++17 or C2x, it expands to [[fallthrough]]; else if the
compiler has __has_attribute and has the __fallthrough__ attribute, then
it expands to __attribute__((__fallthrough__)); else it expands to an
empty statement, with a /* fallthrough */ comment (it's a do {} while
(0) statement, because users of this macro need to use a semicolon,
because [[fallthrough]] and __attribute__((__fallthrough__)) require a
semicolon).
Clang before Clang 10 and GCC before GCC 7 have problems with using
__attribute__ as a sole statement and warn about a "declaration not
declaring anything", so fall back to using the /* fallthrough */ comment
if we are using those older compiler versions.
Applications using SDL are also free to use this macro (because it is
defined in begin_code.h).
All existing /* fallthrough */ comments have been replaced with this
macro. Some of them were unnecessary because they were the last case in
a switch; using SDL_FALLTHROUGH in those cases would result in a compile
error on compilers that support __fallthrough__, for having a
__attribute__((__fallthrough__)) statement that didn't immediately
precede a case label.
Case fallthrough warnings can be suppressed using the __fallthrough__
compiler attribute. Unfortunately, not all compilers have this
attribute, or even have __has_attribute to check if they have the
__fallthrough__ attribute. [[fallthrough]] is also available in C++17
and the next C2x, but not everyone uses C++17 or C2x.
So define the SDL_FALLTHROUGH macro to deal with those problems - if we
are using C++17 or C2x, it expands to [[fallthrough]]; else if the
compiler has __has_attribute and has the __fallthrough__ attribute, then
it expands to __attribute__((__fallthrough__)); else it expands to an
empty statement, with a /* fallthrough */ comment (it's a do {} while
(0) statement, because users of this macro need to use a semicolon,
because [[fallthrough]] and __attribute__((__fallthrough__)) require a
semicolon).
Applications using SDL are also free to use this macro (because it is
defined in begin_code.h).
All existing /* fallthrough */ comments have been replaced with this
macro. Some of them were unnecessary because they were the last case in
a switch; using SDL_FALLTHROUGH in those cases would result in a compile
error on compilers that support __fallthrough__, for having a
__attribute__((__fallthrough__)) statement that didn't immediately
precede a case label.
This prevents conflicts with hidapi linked with applications, as well as allowing applications to make use of HIDAPI on Android and other platforms that might not normally have an implementation available.
Add a function to clamp a value to a range.
SDL_clamp(x, a, b) is equivalent to SDL_min(a, SDL_max(x, b)): it
ensures that x is not smaller than a, nor larger than b.
While, as best I can tell, this isn't actually standardised anywhere,
it's a very useful function/macro to have.
The __clang_major__ and __clang_minor__ macros provide a marketing
version, which is not necessarily comparable for clang distributions
from different vendors[1]. In practice, the versioning scheme for
Apple's clang is indeed completely different to that of the llvm.org
releases. It is thus preferable to check for features directly rather
than comparing versions.
In this specific case, __builtin_bswap16 was being used with older
Apple clang versions that don't support it.
[1] https://clang.llvm.org/docs/LanguageExtensions.html#builtin-macros
In a more ideal world, we'd use the appropriate `__attribute__` here, but
it's one thing in a public header that probably shouldn't be there at all, so
this is good enough for now.
Fixes#4307.
SDL has been missing a bunch of these 'isX' functions for some time,
where X is some characteristic of a given character.
This commit adds the rest of them to the SDL stdlib, so now we have:
- SDL_isalpha()
- SDL_isalnum()
- SDL_isblank()
- SDL_iscntrl()
- SDL_isxdigit()
- SDL_ispunct()
- SDL_isprint()
- SDL_isgraph()
The DJGPP compiler emits many warnings for conflicts between print
format specifiers and argument types. To fix the warnings, I added
`SDL_PRIx32` macros for use with `Sint32` and `Uint32` types. The macros
alias those found in <inttypes.h> or fallback to a reasonable default.
As an alternative, print arguments could be cast to plain old integers.
I opted slightly for the current solution as it felt more technically correct,
despite making the format strings more verbose.
Cameron Cawley
stdlib: Added SDL_round, SDL_roundf, SDL_lround and SDL_lroundf
The default implementation is based on the one used in the Windows RT video driver.
For systems without strlcpy and strlcat, just declare them as if they exist;
the analyzer possibly still knows the details of these functions and can
utilize that in its analysis.
Most of this patch was from meyraud705 at gmail and Martin Gerhardy. Thanks!
Fixes Bugzilla #5163.
