read code now claims and releases png_ptr->zstream, like the write code.
The bug whereby the progressive reader failed to release the zstream
is now fixed, all initialization is delayed, and the code checks for
changed parameters on deflate rather than always calling
deflatedEnd/deflateInit.
problems. This is an intermediate check-in that solves the immediate problems
and introduces one performance improvement (avoiding a copy via png_ptr->zbuf.)
Further changes will be made to make ICC profile handling more secure.
options declares 'index' as a global, causing a warning if it is used as a
local variable. GCC 64-bit warns about assigning a (size_t) (unsigned 64-bit)
to an (int) (signed 32-bit). MSVC, however, warns about using the
unary '-' operator on an unsigned value (even though it is well defined
by ANSI-C to be ~x+1). The padding calculation was changed to use a
different method. Removed the tests on png_ptr->pass.
all potentially valid ICC profiles and reject obviously invalid ones.
It now uses png_error() to do so rather than casually writing a PNG
without the necessary color data.
generator. The generator generates images that test the full range of sample
values, allow the error numbers in pngstest to be tuned and checked. makepng
also allows generation of images with extra chunks, although this is
still work-in-progress.
store intermediate files, or intermediate in-memory data, while processing
image data with the simplified API. The option makes the files larger
but faster to write and read. pngstest now uses this by default; this
can be disabled with the --slow option.
to reset the user limits to safe ones if PNG_SAFE_LIMITS is defined.
To enable, use CPPFLAGS=-DPNG_SAFE_LIMITS on the configure command
or put #define PNG_SAFE_LIMITS_SUPPORTED in pnglibconf.h.prebuilt.
(Reverted previous implementation of PNG_SECURE.)
pngpread.c and use the sequential png_handle_tEXt, etc., in pngrutil.c;
now that png_ptr->buffer is inaccessible to applications, the special
handling is no longer useful.
FLOATING_POINT options were switched off, png.h ended up with lone ';'
characters. This is not valid ANSI-C outside a function. The ';'
characters have been moved inside the definition of PNG_FP_EXPORT and
PNG_FIXED_EXPORT. 2) If either option was switched off, the declaration
of the corresponding functions were completely omitted, even though some
of them are still used internally. The result is still valid, but
produces warnings from gcc with some warning options (including -Wall). The
fix is to cause png.h to declare the functions with PNG_INTERNAL_FUNCTION
when png.h is included from pngpriv.h.
Fixed a memory overwrite bug in simplified read of RGB PNG with
non-linear gamma Also bugs in the error checking in pngread.c and changed
quite a lot of the checks in pngstest.c to be correct; either correctly
written or not over-optimistic. The pngstest changes are insufficient to
allow all possible RGB transforms to be passed; pngstest cmppixel needs
to be rewritten to make it clearer which errors it allows and then changed
to permit known inaccuracies.
The API is extremely inaccurate for sRGB conversions because it uses an 8-bit
intermediate linear value and it does not use the sRGB transform, so it
suffers from the known instability in gamma transforms for values close
to 0 (see Poynton). The net result is that the calculation has a maximum
error of 14.99/255; 0.5/255^(1/2.2). pngstest now uses 15 for the
permitted 8-bit error. This may still not be enough because of arithmetic
error.
to the background parameter of png_image_finish_read. The --background
option is now done automagically only when required, so that commandline
option no longer exists.
Also some layout regularization and removal of introduced tab characters
(replaced with 3-character indentation). Obsolete macros identified by
autoupdate have been removed; the replacements are all in 2.59 so
the pre-req hasn't been changed. --enable-werror checks for support
for -Werror (or the given argument) in the compiler. This mimics the
gcc configure option by allowing -Werror to be turned on safely; without
the option the tests written in configure itself fail compilation because
they cause compiler warnings.
compiler issues slightly different warnings from those issued by the
current vesions of GCC. This eliminates those warnings by
adding/removing casts and small code rewrites.
those uses of png_memcpy that were doing a simple assignment to assignments
(all those cases where the thing being copied is a non-array C L-value.)
Added some error checking to png_set_*() routines and removed the
reference to the non-exported function png_memcpy() from example.c. Fixed
the Visual C 64-bit build - it requires jmp_buf to be aligned, but it had
become misaligned.
Added new "png_structrp" typedef. Because of the
way libpng works both png_info and png_struct are always accessed via a
single pointer. This means adding C99 'restrict' to the pointer gives
the compiler some opportunity to optimize the code. This change allows that.
Previously it was disabled whenever internal fixed point arithmetic was
selected, which meant it didn't exist even on systems where FP was available
but not preferred.
These changes alter how the tricky allocation of the initial png_struct and
png_info structures are handled. png_info is now handled in pretty much the
same way as everything else, except that the allocations handle NULL return
silently. png_struct is changed in a similar way on allocation and on
deallocation a 'safety' error handler is put in place (which should never
be required). The error handler itself is changed to permit mismatches
in the application and libpng error buffer size; however, this means a
silent change to the API to return the jmp_buf if the size doesn't match
the size from the libpng compilation; libpng now allocates the memory and
this may fail. Overall these changes result in slight code size
reductions; however, this is a reduction in code that is always executed
so is particularly valuable. Overall on a 64-bit system the libpng DLL
decreases in code size by 1733 bytes. pngerror.o increases in size by
about 465 bytes because of the new functionality.
of parallelism during 'make' the use of the same temporary file names such
as 'dfn*' can result in a race where a temporary file from one arm of the
build is deleted or overwritten in another arm. This changes the
temporary files for suffix rules to always use $* and ensures that the
non-suffix rules use unique file names.
Some compilers fault 'extern const' data declarations (because the data is
not initialized); this turns on const-ness only for compilers where
this is known to work.
using g++. The compiler imposes C++ rules on the C source; thus it
is desireable to make the source work with either C or C++ rules
without throwing away useful error information. This change adds
png_voidcast to allow C semantic (void*) cases or the corresponding
C++ static_cast operation, as appropriate.
The slightly modified tables reduce the number of 16-bit values that
convert to an off-by-one 8-bit value. The "makesRGB.c" code that was used
to generate the tables is now in a contrib/sRGBtables sub-directory.
the sBIT fields in the test pixel as 0, which resulted in a floating
point division by zero which was irrelevant but causes systems where
FP exceptions cause a crash. Added code to pngvalid to turn on FP
exceptions if the appropriate glibc support is there to ensure this is
tested in the future.
casts. The compression_type parameter is always assigned to, so must
be non-NULL. The cast of the profile length potentially truncated the
value unnecessarily on a 16-bit int system, so the cast of the (byte)
compression type to (int) is specified by ANSI-C anyway.
changes the 'Paeth' reconstruction function to improve the GCC code
generation on x86. The changes are only part of the suggested ones;
just the changes that definitely improve speed and remain simple.
The changes also slightly increase the clarity of the code. In a
in pngmem.c; pngvalid would attempt to call png_error() if the allocation
of a png_struct or png_info failed. This would probably have led to a
crash. The pngmem.c implementation of png_malloc() included a cast
to png_size_t which would fail on large allocations on 16-bit systems.
The logical shift fix for Microsoft Visual C is required by other compilers,
so this enables that fix for all compilers when using compile-time constants.
Under MSYS 'byte' is a name declared in a system header file, so we
changed the name of a local variable to avoid the warnings that result.
is not byte aligned, while reading. Prior to libpng-1.5.6 libpng would
overwrite the end of the image if the row width is not an exact multiple
of 8 bits and the image is not interlaced.
These fixes attend to most of the errors revealed in pngvalid, however doing
the gamma work twice results in inaccuracies that can't be easily fixed.
There is now a warning in the code if this is going to happen.
It is too risky. Exactly how png_ptr->zbuf is used is under control of the
individual chunk implementation and there could easily be significant changes
within a major release.
small percentage for 16-bit and 32-bit pixels in the typical case where the
output row buffers are appropriately aligned. The optimization was not
previously possible because the png_struct buffer was always misaligned.
caused by a bug in the code that attempted to align it; the code needs to
subtract one from the pointer to take account of the filter byte prepended to
each row.
generality of the code, allowing it to be optimized for Adam7 interlace. The
masks passed to png_combine_row() are now generated internally, avoiding
some code duplication and localizing the interlace handling somewhat.
to conditions where types that are 32 bits in the GCC 32-bit
world (uLong and png_size_t) become 64 bits in the 64-bit
world. This produces potential truncation errors which the
compiler correctly flags.
