The macro underreported the size (by up to 512 bytes) of an 8-bit non-color
palette based memory format because it failed to take into account that the
memory palette has to be expanded to full RGB when it is written to PNG.
This is not likely to be a serious bug because the macro is new, the memory
format in question is likely to be rarely used and the result of an undersized
buffer fails in a safe way.
Signed-off-by: John Bowler <jbowler@acm.org>
This implements an API and provides a number of assist macros to allow an
application which uses the simplified API write to bypass stdio and write
directly to memory.
It also includes some warnings (png.h) and some check code to detect *possible*
overflow in the ROW_STRIDE and simplified image SIZE macros. This disallows
image width/height/format that *might* overflow. A quiet API change that limits
in-memory image size (uncompressed) to less that 4GByte and image row size
(stride) to less than 2GByte.
Signed-off-by: John Bowler <jbowler@acm.org>
input that was made in version 1.6.17beta01, to preserve legacy
behavior even though it was incorrect. Instead, added new API
png_set_filter_16() and png_set_add_alpha_16() that set a flag to
make png_do_read_filter() interpret the filler bytes properly.
replacing the value that is illegal in the PNG spec, in both signed and
unsigned values, with 0. Illegal unsigned values (anything greater than or equal
to 0x80000000) can still pass through, but since these are not illegal
in ANSI-C (unlike 0x80000000 in the signed case) the checking that
occurs later can catch them (John Bowler).
0x8000 flag definitions on 16-bit systems. They aren't supported
yet the defs *probably* work, however it seems much safer to do this
and be advised if anyone, contrary to advice, is building libpng 1.6
on a 16-bit system. It also adds back various switch default clauses
for GCC; GCC errors out if they are not present (with an appropriately
high level of warnings).
