This eliminates "illegal instruction" errors when running libjpeg-turbo
under Linux on PowerPC chips that lack AltiVec support (e.g. the old
7XX/G3 models but also the newer e5500 series.)
The JSIMD_FORCE* environment variables previously meant "force the use
of this instruction set if it is available but others are available as
well", but that did nothing on ARM platforms, since there is only ever
one instruction set available. Since the ARM and MIPS CPU feature
detection code is less than bulletproof, and since there is only one
SIMD instruction set (currently) supported on those platforms, it makes
sense for the JSIMD_FORCE* environment variables on those platforms to
actually force the use of the SIMD instruction set, thus bypassing the
CPU feature detection code.
This addresses a concern raised in #88 whereby parsing /proc/cpuinfo
didn't work within a QEMU environment. This at least provides a
workaround, allowing users to force-enable or force-disable SIMD
instructions for ARM and MIPS builds of libjpeg-turbo.
This commit adds back instructive comments in the image-space
algorithms, similar to those in the SSE2 code. These comments make it
easier to follow the flow of data through the algorithms.
Expand collect_args/uncollect_args macros so that the number of
arguments can be specified. This prevents unnecessary push and mov
instructions.
NOTE: On Windows, the push/pop of xmm6 and xmm7 had to be moved to the
other end of the macro to ensure that rsp is aligned on a 16-byte
boundary.
28d1a1300c introduced the line
"nasm.exe should be in your PATH". This commit corrects an oversight in
8f1c0a681c /
e5091f2cf3 whereby this line should have
been extended to include yasm.exe.
The IJG convention is to format copyright notices as:
Copyright (C) YYYY, Owner.
We try to maintain this convention for any code that is part of the
libjpeg API library (with the exception of preserving the copyright
notices from Cendio's code verbatim, since those predate
libjpeg-turbo.)
Note that the phrase "All Rights Reserved" is no longer necessary, since
all Buenos Aires Convention signatories signed onto the Berne Convention
in 2000. However, our convention is to retain this phrase for any files
that have a self-contained copyright header but to leave it off of any
files that refer to another file for conditions of distribution and use.
For instance, all of the non-SIMD files in the libjpeg API library refer
to README.ijg, and the copyright message in that file contains "All
Rights Reserved", so it is unnecessary to add it to the individual
files.
The TurboJPEG code retains my preferred formatting convention for
copyright notices, which is based on that of VirtualGL (where the
TurboJPEG API originated.)
Calling jpeg_stdio_dest() followed by jpeg_mem_dest(), or jpeg_mem_src()
followed by jpeg_stdio_src(), is dangerous, because the existing opaque
structure would not be big enough to accommodate the new source/dest
manager. This issue was non-obvious to libjpeg-turbo consumers, since
it was only documented in code comments. Furthermore, the issue could
also occur if the source/dest manager was allocated by the calling
program, but it was not allocated with enough space to accommodate the
opaque stdio or memory source/dest manager structs. The safest thing to
do is to throw an error if one of these functions is called when there
is already a source/dest manager assigned to the object and it was
allocated elsewhere.
Closes#78, #79
The jpeg-7/jpeg-8 APIs/ABIs require arithmetic coding, and the jpeg-8
API/ABI requires the memory source/destination manager, so this commit
causes the build system to ignore --with-arith-enc/--without-arith-enc
and --with-arith-dec/--without-arith-dec (and the equivalent CMake
variables-- WITH_ARITH_ENC and WITH_ARITH_DEC) when v7/v8 API/ABI
emulation is enabled. Furthermore, the CMake build system now ignores
WITH_MEM_SRCDST whenever WITH_JPEG8 is specified (the autotools build
system already did that.)
GCC does support UAL syntax (strbeq) if the ".syntax unified" directive
is supplied. This directive is supported by all versions of GCC and
clang going back to 2003, so it should not create any backward
compatibility issues.
Based on 1264349e2fCloses#76
If wmic.exe wasn't available, then CMakeLists.txt would call
"cmd /C date /T" and parse the result in order to set the BUILD
variable. However, the parser assumed that the date was in MM/DD/YYYY
format, which is not generally the case unless the user's locale is U.S.
English with the default region/language settings for that locale.
This commit modifies CMakeLists.txt such that it uses the
string(TIMESTAMP) function available in CMake 2.8.11 and later to set
the BUILD variable, thus eliminating the need to use wmic.exe or any
other platform-specific hack.
This commit also modifies the build instructions to remove any reference
to CMake 2.6 (which hasn't been supported by our build system since
libjpeg-turbo 1.3.x.)
Closes#74
At one time, it was possible to use CMake to build under Cygwin, but
that hasn't worked since 1.4.1 (due to the Huffman codec changes that
now require SIZEOF_SIZE_T to be defined for non-WIN32 platforms) and may
have even been broken before that. Originally, we used the "date"
command under MSYS in order to obtain the default build number, but that
was rendered unnecessary by 5e3bb3e9 (v1.3 beta.) 9fe22dac (1.4 beta)
further modified CMakeLists.txt so that the "date" command was only used
on Cygwin, but for unexplained reasons, that commit also applied the
(now vestigial) code to all non-WIN32 platforms. This prevented
CMakeLists.txt from displaying an error if someone attempted to use the
CMake build system on Un*x platforms, and that may have been behind the
flurry of pull requests and issues-- including #21, #29, #37, #58, #73--
complaining that the CMake build system didn't work on Un*x platforms
(although it was not until #73 that this bug came to light.)
This commit removes all vestiges of Un*x support from the CMake build
system and makes it clear that CMake cannot be used to build
libjpeg-turbo on non-WIN32 platforms. It is our position that CMake
will not be supported on non-WIN32 platforms until/unless the autotools
build system is removed, and this will not happen without broad support
from the community (including major O/S vendors.) If you are in favor
of migrating the entire build system to CMake, then please make your
voice heard by commenting on #56.
Even though tjDecompressToYUV2() is mostly just a wrapper for
tjDecompressToYUVPlanes(), tjDecompressToYUV2() still calls
jpeg_read_header(), so it needs to properly set up the libjpeg error
handler prior to making this call. Otherwise, under very esoteric (and
arguably incorrect) use cases, a program could call tjDecompressToYUV2()
without first checking the JPEG header using tjDecompressHeader3(), and
if the header was corrupt, then the libjpeg API would invoke
my_error_exit(). my_error_exit() would in turn call longjmp() on the
previous value of myerr->setjmp_buffer, which was probably set in a
previous TurboJPEG function, such as tjInitDecompress(). Thus, when a
libjpeg error was triggered within the body of tjDecompressToYUV2(), the
PC would jump to the error handler of the previous TurboJPEG function,
and this usually caused stack corruption in the calling program (because
the signature and return type of the previous TurboJPEG function
probably wasn't the same as that of tjDecompressToYUV2().)
Actually, what happened was that the longjmp() call within
my_error_exit() acted on the previous value of myerr->setjmp_buffer,
which was probably set in a previous TurboJPEG function, such as
tjInitDecompress(). Thus, when a libjpeg error was triggered within
the body of tjDecompressToYUV2(), the PC jumped to the error handler
of the previous TurboJPEG function, and this usually caused stack
corruption in the calling program (because the signature and return
type of the previous TurboJPEG function probably wasn't the same.)
Even though tjDecompressToYUV2() is mostly just a wrapper for
tjDecompressToYUVPlanes(), tjDecompressToYUV2() still calls
jpeg_read_header(), so it needs to properly set up the libjpeg error
handler prior to making this call. Otherwise, under very esoteric (and
arguably incorrect) use cases, a program can call tjDecompressToYUV2()
without first checking the JPEG header using tjDecompressHeader3(), and
if the header is corrupt, tjDecompressToYUV2() will abort without
triggering an error.
Fixes#72
<sigh> GitHub doesn't render indented text the same as my local MarkDown
viewer (MacDown), so it's necessary to indent "... OR ..." by 3 spaces
so both will display it on the same indentation level as "Visual C++
2005 or later" and "MinGW".
Indent "... OR ..." to make it clear that the choice is between Visual
C++ and MinGW, not Visual C++ and MinGW + NASM. Move NASM to the top of
the list to make that even more clear. Make it clear that nasm.exe
should be in the PATH.
Addresses concerns raised in #70
This extends the fix in 6709e4a0cf to
include binary PPM/PGM files, thus preventing a malformed binary
PPM/PGM input file from triggering an overrun of the rescale array and
potentially crashing cjpeg.
Note that this issue affected only cjpeg and not the underlying
libjpeg-turbo libraries, and thus it did not represent a security
threat.
Thanks to @hughdavenport for the discovery.
This is a common practice in other infrastructure libraries, such as
OpenSSL and libpng, because it makes it easy to examine an application
binary and determine which version of the library the application was
linked against.
Closes#66
This prevents a malformed motion-JPEG frame (MJPEG frames lack Huffman
tables) from causing the "fast path" of the Huffman decoder to read
uninitialized memory. Essentially, this is doing the same thing for
MJPEG frames as 43d8cf4d45 did for regular
images.
Running 'make -j{jobs}' on a build that was configured with Java
(--with-java) would previously cause an error:
make: *** No rule to make target `TJExample.class', needed by
`turbojpeg.jar'.
It seems that parallel make doesn't understand that the files in
$(JAVA_CLASSES) are all generated from the same invocation of javac, so
it tries to parallelize the building of those files (which of course
doesn't work.) This patch instead makes turbojpeg.jar depend on
classnoinst.stamp. This effectively creates a synchronization fence,
since that file is only created when all of the class files have been
built.
Fixes#62
The x86-64 SIMD accelerations for Huffman encoding used incorrect
stack math to save xmm8-xmm11 on Windows. This caused TJBench to
always report 1 Mpixel/sec for the compression performance, and it
likely would have caused other application issues as well.
