This implements a new chunk parse implementation that can be shared, it
is currently shared by the progressive reader and the sequential one
(not, yet, the writer).
The patch also implements shared transform handling that is used
throughout.
Signed-off-by: John Bowler <jbowler@acm.org>
pnglibconf.dfa, that can be reset by the user at build time or run time.
This provides a more robust defense against DOS and as-yet undiscovered
overflows.
Removed "option READ_COMPRESSED_TEXT enables READ_TEXT" from pnglibconf.dfa,
to make it possible to configure a libpng that supports iCCP but not TEXT.
Removed "option WRITE_COMPRESSED_TEXT enables WRITE_TEXT" from pnglibconf.dfa
Only mark text chunks as written after successfully writing them.
Added "option READ_iCCP enables READ_COMPRESSED_TEXT" to pnglibconf.dfa
Removed unused "text_len" parameter from private function png_write_zTXt().
Conditionally compile some code in png_deflate_claim(), when
PNG_WARNINGS_SUPPORTED and PNG_ERROR_TEXT_SUPPORTED are disabled.
Replaced repeated code in pngpread.c with PNG_PUSH_SAVE_BUFFER_IF_FULL.
Added "chunk iTXt enables TEXT" and "chunk zTXt enables TEXT"
to pnglibconf.dfa.
Edit and fix typos in comments.
function definitions before the place where they are called so that
they can be masde static. Move the intrapixel functions and the
grayscale palette builder out of the png?tran.c files. The latter
isn't a transform function and is no longer used internally, and the
former MNG specific functions are better placed in pngread/pngwrite.c
Fixed 'minimal' builds. Various obviously useful minimal configurations
don't build because of missing contrib/libtests test programs and overly
complex dependencies in scripts/pnglibconf.dfa. This change adds
contrib/conftest/*.dfa files that can be used in automatic build
scripts to ensure that these configurations continue to build.
Enabled WRITE_INVERT and WRITE_PACK in contrib/pngminim/encoder.
prefixing. This adds an API to set optimization options externally,
providing an alternative and general solution for the non-portable
run-time tests used by the ARM Neon code. It also makes those tests
compile and link on Android. The order of settings vs options in
pnglibconf.h is reversed to allow settings to depend on options and
options can now set (or override) the defaults for settings.
links and tests against zlib with a prefix; tests have been clarified; and
irrelevant or obsolete things (as defined by the autotools man page) have
been removed.
handling png_struct members rearranged - partly to reorder to avoid packing,
partly to put frequently accessed members at the start and partly to make
the grouping more clear. png_set_filter code has been rewritten and the
code shared with png_write_start_row moved to a common function. Comments
in png.h have been made more clear. Minor fixes to
contrib/libtests/timepng.c and some of the png_*_tRNS logic, including
more error detection in png_set_tRNS.
READ_GAMMA. Prior to 1.6.0 switching off READ_GAMMA did unpredictable things
to the interfaces that use it (specifically, png_do_background in 1.4 would
simply display composite for grayscale images but do composition
with the incorrect arithmetic for color ones). In 1.6 the semantic
of -DPNG_NO_READ_GAMMA is changed to simply disable any interface that
depends on it; this obliges people who set it to consider whether they
really want it off if they happen to use any of the interfaces in
question (typically most users who disable it won't).
management system (CMS). In practice it is not possible to obtain cHRM
information reliably using just the end-point tags because they do not exist
in the vast majority of profiles. Instead it is necessary to run the endpoints
through the ICC colorimetric intent transform (as described in the v4
spec). Since this is likely to be too much code inside libpng for too
little gain (it implies a fairly complete CMS implementation) the code
has been changed to allow an external CMS to be used. This code is
temporarily disabled until a suitable set of test cases using one or more
external CMS implementations have been implemented.
png_set_keep_unknown_chunks() to be turned off if not required and causes
both read and write to behave appropriately (on read this is only possible
if the user callback is used to handle unknown chunks). The change
also removes the support for storing unknown chunks in the info_struct
if the only unknown handling enabled is via the callback, allowing libpng
to be configured with callback reading and none of the unnecessary code.
control of the unknown handling, corrects the pre-existing bug where
the per-chunk 'keep' setting is ignored and makes it possible to skip
IDAT chunks in the sequential reader (broken in earlier 1.6 versions).
There is a new test program, test-unknown.c, which is a work in progress
(not currently part of the test suite). Comments in the header files now
explain how the unknown handling works.
default. Also changed some warnings in the iCCP and sRGB handling
from to benign errors. Configuration now makes read benign
errors warnings and write benign errors to errors by default (thus
changing the behavior on read). The simplified API always forces
read benign errors to errors (regardless of the system default, unless
this is disabled in which case the simplified API can't be built.)
functions [rw]util.c. A new shared keyword check routine was also added
and the 'zbuf' is no longer allocated on progressive read. It is now
possible to call png_inflate() incrementally.
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.)
