Improve:
The pngtest program used to be rather relaxed upon seeing invalid
parameters in callbacks: it either ignored them, or it bailed out
of the callbacks, essentially sweeping the bug under the rug.
But no more. Now it terminates with a severe `png_error`, in which
it says what's broken and where.
Improve:
`PNG_DEBUG`, defined externally at build time, and defaulting to zero,
was assumed to be non-negative. Now it's checked.
Clean up:
In a very distant past, the pngtest program used to "travel" across
libpng versions, on its own, not necessarily accompanied by the actual
library version that it was meant to test. However, this stopped being
the case, and now is as good a time as any to remove the compatibility
workarounds that had made the aforementioned "travel" possible.
Other chores include:
* The refactoring of the user-defined chunk handling routines;
* The cleanup of an unnecessary use of volatile;
* The various cosmetic improvements of code and comments.
This adds a new configuration file, 'contrib/conftest/basic.dfa' which
disables unused APIs on a test Linux-based system. So support the
configuration several fixes were necessary in the test programs so that
the tests are skipped correctly when APIs are not available.
The configuration has been tested on a range of common Linux apps
including web browser code (qtwebengine), image processing code (e.g.
ImageMagick) and general display code (X11, Qt5 and Qt6, KDE). Overall
this first step reduces libpng linked code and data size to about 2/3 of
the full configuration.
To use the new test simply copy basic.dfa to 'pngusr.dfa' in the root of
the source directory and build.
Signed-off-by: John Bowler <jbowler@acm.org>
Ensure that row_buf is deallocated not only after a read error, but
also after a write error.
Use the format "%p" instead of "0x%08lx" for printf-ing row_buf in
a portable manner.
In v1.6.0, compiler support for const became a requirement.
It should be used consistently. To maintain backwards compatibility,
PNG_CONST is still maintained in deprecated form.
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.
Moved testing of bad pngs into a separate tests/pngtest-badpngs script
Added the --xfail (expected FAIL) option to pngtest.c. It writes XFAIL
in the output but PASS for the libpng test.
