We should use `FILE *` instead of `FILE*` or `(FILE*)`, consistently,
as we should for all other pointer types. Moreover, when we refer to
standard stdio file objects in comments and in documentation, we should
use the term "FILE objects" consistently.
Lastly, we clarify in a comment in example.c that `PNG_STDIO_SUPPORTED`
is true only when the stdio support is both available in the system and
accessible in the user's libpng build.
This is a cherry-pick of commit c63c5463903014c904b540216c2784023fb8c1c8
from branch 'libpng18'.
Reviewed-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
Remove #ifdef sections and other workarounds for old Windows compilers
that lacked proper support for Win32, including, especially, support
for the Win32 stdio API.
This is a cherry-pick of commit e936211760ddf0ed4a4711ea897b59395dfd206e
from branch 'libpng18'.
Reviewed-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
In libpng version 1.6.45 we inadvertently used a declaration after
a statement, which works for compilers supporting C99 and newer,
but fails with C89 compilers, which we are still supporting in the
branch 'libpng16'.
Moreover, in commit 92e8581f12d4570b777eaabfbe1f4243b7b80c04, we used
the macro `PNG_FIXED_EXPORT` in a manner that introduced a spurious ';'
character, which broke the build for all standard-conforming compilers.
Reviewed-by: Cosmin Truta <ctruta@gmail.com>
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
Apart from the png.h change, these files are machine-generated.
Reviewed-by: Cosmin Truta <ctruta@gmail.com>
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
This adds APIs to get/set the two remaining new PNG-v3 colour space
chunks. The mDCV API matches that of cHRM. Both chunks support
floating point APIs (all values in the two chunks are real numbers).
Both chunks have a new encoded type, a four-digit-precision fixed-point
number, which cannot be represented in the existing `png_fixed_point`
type, so a `png_uint_32` is used.
Test examples for cICP, cLLI and mDCV are now in pngtest.png, and a
necessary change to the pngunknown.c test program has been made to
accomodate the additions.
Reviewed-by: Cosmin Truta <ctruta@gmail.com>
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
This chunk was added in the third edition of the PNG specification and
contains Coding Independent Code Points (related to color space
description). It is fairly simple as it only contains four fields of one
byte each: Colour Primaries, Transfer Function, Matrix Coefficients,
Video Full Range Flag.
The test file originally comes from the related WPT test case:
https://github.com/web-platform-tests/wpt/blob/master/png/support/cicp-display-p3.png
Note that I reencoded the file to make it match libpng's default
encoding parameters (it only modifies the IDAT chunk).
This is a cherry-pick of commit 65925ad4b2cbed934d5d850fe764dc46c4becbcb
from branch 'libpng18'.
Reviewed-by: John Bowler <jbowler@acm.org>
Reviewed-by: Chris Blume <ProgramMax@gmail.com>
Reviewed-by: Cosmin Truta <ctruta@gmail.com>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
The leading blank lines are apparently an artefact of an older source
control system. They are not required and they look like accidents,
because starting a source file with a blank line is not a regular habit
of software developers nowadays.
This is a cherry-pick of commit 37cc20add8fb5b83bb5299a26cd3b41e0f776017
from branch 'libpng18'.
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
The version macros `PNG_LIBPNG_VER_SONUM` and `PNG_LIBPNG_VER_DLLNUM`
weren't always in sync, but they should be, going forward.
Or, better yet, we should keep them in, deprecated, and introduce
`PNG_LIBPNG_VER_SHAREDLIB` for all shared library builds of all kinds
on all platforms.
It is unknown how many user applications have been using these macros.
We have been using `PNG_LIBPNG_VER_DLLNUM` for pngwin.rc, for example.
Which, by the way, was last updated in 2009.
This fixes commit 27e548af2518ff8d278b45c40d11ad1bdd68eaa0.
The macro `png_check_sig` has been deprecated and remained untested
for decades. And yet, somehow it escaped from all past API cleanups.
Also update the libpng manual.
Reported-by: Matthieu Darbois
This removes the default build of an undocumented feature to disable
Adler32 checksums on those systems where it was the default.
The PR is motived by github #187 however it fixes a much more general
problem (#187 is limited to an issue where libpng "crashes" on some
manufacturer systems). The fix is based on a suggestion by @sgowdev who
is the originator of the issue.
When libpng disables the checking of Adler32 checksums it does so by an
undocumented and therefore possibly unsupported call to a zlib function
which does not exist in some versions of zlib.
Fortunately libpng only does this if the caller of libpng explicitly
asks for it to happen. Unfortunately the call to the undocumented
function is still in the compiled and built libpng and this means that
on some systems (as identified in #187) libpng can fail to load or maybe
even crash.
The libpng authors are currently unaware of any program or system that
uses this feature and none has been identified by the contributors to
In this fix an option is added to *enable* the code so that by default
the code is *disabled* - this is a simple generalization of the
suggestion by @sgowdev.
BENEFITS: the problem is eliminated, users of the functionality, if any,
are idenfified, the functionality can be implemented correctly in the
future or it can be removed. Hardly anyone complains.
COSTS: someone will complain that they have to enable an option in a
libpng build to use a feature that never worked consistently in the
first place.
This patch has been tested both with the option enabled and with it
disabled via pngusr.dfa. Tests, checks pass with cmake and configure,
make distcheck passes on configure.
Reported-by: Stephen Gowen <dev.sgowen@gmail.com>
Signed-off-by: John Bowler <jbowler@acm.org>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
At a certain step in the configuration process, `gcc -Wundef`
complained about using `INT_MAX` without a definition in png.h,
which is easily fixable with an include.
We would rather not add any extra dependencies to png.h, however,
so we use some unsigned int arithmetic magic instead.
The new libpng license comprises the terms and conditions from the zlib
license, and the disclaimer from the Boost license.
The legacy libpng license, used until libpng-1.6.35, is appended to the
new license, following the precedent established in the Python Software
Foundation License version 2.
From now on, the list of contributing authors shall be maintained in a
separate AUTHORS file.
The lists of previous contributing authors, mentioned in the legacy
libpng license and considered to be an integral part of that license,
are kept intact, with no further updates.
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
