libjpeg-turbo has never really supported such compilers, since (AFAIK)
they are non-existent on any modern computing platform and thus
impossible for us to test. (Also, the TurboJPEG API would break without
unsigned chars.)
Furthermore, the unified CMake-based build system introduced in 2.0
always defines HAVE_UNSIGNED_CHAR, so retaining other code paths is
pointless. Eliminating support for compilers without unsigned char
eliminates the need for the GETJSAMPLE() macro, which improves the
readability of many parts of the code as well as improving the
performance of writing Targa and Windows BMP files.
Fixes#317
- When referring to specific clauses, annexes, tables, and figures, a
"timed reference" (a reference that includes the year) must be used in
order to avoid confusion.
- "CCITT" = "ITU-T"
- Replace ambiguous "JPEG spec" with the specific document number.
This re-introduces a feature of the obsolete system-specific libjpeg
memory managers-- namely the ability to limit the amount of main memory
used by the library during decompression or multi-pass compression.
This is mainly beneficial for two reasons:
- Works around a 2 GB limit in libFuzzer
- Allows security-sensitive applications to set a memory limit for the
JPEG decoder so as to work around the progressive JPEG exploit
(LJT-01-004) described here:
http://www.libjpeg-turbo.org/pmwiki/uploads/About/TwoIssueswiththeJPEGStandard.pdf
This commit also removes obsolete documentation regarding the MS-DOS
memory manager (which itself was removed long ago) and changes the
documentation of the -maxmemory switch and JPEGMEM environment variable
to reflect the fact that backing stores are never used in libjpeg-turbo.
Inspired by:
066fee2e7dCloses#143
The IJG README file has been renamed to README.ijg, in order to avoid
confusion (many people were assuming that that was our project's README
file and weren't reading README-turbo.txt) and to lay the groundwork for
markdown versions of the libjpeg-turbo README and build instructions.
