EXIF data can be stored in an eXIf chunk before IDAT, or after IDAT,
but the entire PNG datastream may contain one eXIf chunk at most.
Introduce the private mode flag PNG_WROTE_eXIf, which is meant to be
used like the PNG_WROTE_tIME flag. The eXIf chunk and the tIME chunk
have the same ordering rules (i.e. no constraints are imposed), and
the same multiplicity rules (i.e. no multiples are allowed), and they
should be initialized and checked using the same algorithm.
This fixes commit cd03aaf7bf0e0c748b8c6cb34a56b402b40d61d0,
previously reverted in 3d57708c9166419b7f5e0bbda2f7a2149112c844.
Reported-by: Ben Bullock <benkasminbullock@gmail.com>
The following pointer subtraction was unnecessary:
((const char*)(ptr)-(const char*)0)
In order to avoid further warnings about casting a wide pointer type
to a narrower integer type, we cast the pointer to the target integer
type through (size_t).
Also fix a comment and reformat the surrounding code.
Delete the structure members used in the 16-bit Turbo C memory models.
Delete the PNG_ABORT declaration used in the 16-bit Windows build.
Stop checking macros (e.g. _WINDOWS) predefined by 16-bit Windows
compilers (but do check the __NT__ macro, which was the only one
predefined by ancient Windows NT compilers).
This is similar to d532334ef (Avoid -Wundef warnings when building
libpng, 2017-11-13), but for the similar symbols used under the other
architectures: always define them, even if just as 0, to avoid gcc
warnings when comparing them with 0 later.
Define this symbol as 0 instead of leaving it undefined when not using
ARM NEON optimizations.
No real changes, but just avoid a bunch of
"PNG_ARM_NEON_IMPLEMENTATION" is not defined, evaluates to 0 [-Wundef]
warnings when building the library.
In order to appease the compiler warnings that might affect the uses
of png_constcast, it should be sufficient to cast the source pointer
type to (const void*), and then to (void*), and then to the destination
pointer type. An intermediate cast through an integer type, such as
(png_ptruint), should not be needed.
Fixes#398
It adds win-arm64 as an arm64 platform, by using a define which
is set to 1 for compilations that target 64-bit ARM processors,
otherwise undefined.
Move deallocation of riffled_palette from png_write_destroy to
png_read_destroy. The reader (not the writer) is the owner of
riffled_palette.
Move allocation and initialization of riffled_palette from
png_do_read_transformations to png_init_palette_transformations.
Allow riffled_palette inside png_struct only if the ARM Neon
optimizations are enabled.
Rename png_riffle_palette_rgba to png_riffle_palette_rgba8, etc.,
to better indicate the strict applicability of these routines.
Fix an unused parameter warning in the build configurations where
riffled palette optimization is not enabled.
Fix indentation.
As per the const correctness rules, top-level const-ness of data
in automatic scopes does not propagate outside of these scopes
(unlike const-ness at lower levels, such as pointers to const data).
Previously, const was used liberally, but inconsistently across the
libpng codebase. Using const wherever applicable is not incorrect.
However, _consistent_ use of const is difficult to maintain in such
conditions.
In conclusion, we shall continue to use const only where doing so is
strictly necessary:
1. If a function guarantees that it will not modify an argument
passed by pointer, the corresponding function parameter should be
a pointer-to-const (const T *).
2. Static data should not be modified, therefore it should be const.
Reference:
Google C++ Style Guide
https://google.github.io/styleguide/cppguide.html#Use_of_const
In v1.6.0, size_t became a required type. It should be used
consistently. To maintain backwards compatibility, png_size_t
is still maintained in deprecated form.
Configure libpng with "configure --enable-intel-sse" or compile
libpng with "-DPNG_INTEL_SSE" in CPPFLAGS to enable it. This patch was
previously applied to libpng-1.6.28rc03 but withdrawn to allow time for QA.
Remove all currently detected cases of unsigned overflow. Detection is
runtime, so test case dependent. The changes to pngvalid.c eliminate
spurious and probably invalid tests with one while loop exception.
Apart from that and the change to the dependence on the intended
unsigned overflow in pngtrans.c the changes are limited to altering the
meme for an unsigned 'x' from:
while (x-- > 0)
to
for (; x > 0; --x)
This works because, in all cases, the control variable is not used in
the loop. The 'while' meme was, at one time, warn'ed by GCC so it is
probably a good change, for some weird religious value of good.
Signed-off-by: John Bowler <jbowler@acm.org>
