libjpeg-turbo has never supported non-ANSI C compilers. Per the spec,
ANSI C compilers must have locale.h, stddef.h, stdlib.h, memset(),
memcpy(), unsigned char, and unsigned short. They must also handle
undefined structures.
Although sizeof(void *) == sizeof(size_t) for all architectures that are
currently supported by libjpeg-turbo, such is not guaranteed by the C
standard. Specifically, CHERI-enabled architectures (e.g. CHERI-RISC-V
or Arm's Morello) use capability pointers that are twice the size of
size_t (128 bits for Morello and RV64), so casting to size_t strips the
upper bits of the pointer (including the validity bit) and makes it
non-deferenceable, as indicated by the following compiler warning:
warning: cast from provenance-free integer type to pointer type will
give pointer that can not be dereferenced
[-Werror,-Wcheri-capability-misuse]
cvalue = values = (JCOEF *)PAD((size_t)values_unaligned, 16);
Ignoring this warning results in a run-time crash. Casting pointers to
uintptr_t, if it is available, avoids this problem, since uintptr_t is
defined as an unsigned integer type that can hold a pointer value.
Since C89 compatibility is still necessary in libjpeg-turbo, this commit
introduces a new typedef for pointer-to-integer casts that uses a
GNU-specific extension available in GCC 4.6+ and Clang 3.0+ and falls
back to using size_t if the extension is unavailable. The only other
options would require C99 or Clang-specific builtins.
Closes#538
When using the in-memory destination manager, it is necessary to
explicitly call the destination manager's term_destination() method if
an error occurs. That method is called by jpeg_finish_compress() but
not by jpeg_abort_compress().
This fixes a potential double free() that could occur if tjCompress*()
or tjTransform() returned an error and the calling application tried to
clean up a JPEG buffer that was dynamically re-allocated by one of those
functions.
After the completion of the start_input() method, it's too late to check
the image size, because the image readers may have already tried to
allocate memory for the image. If the width and height are excessively
large, then attempting to allocate memory for the image could slow
performance or lead to out-of-memory errors prior to the fuzz target
checking the image size.
NOTE: Specifically, the aforementioned OOM errors and slow units were
observed with the compression fuzz targets when using MSan.
This limits the tjLoadImage() behavioral changes to the scope of the
compress_fuzzer target. Otherwise, TJBench in fuzzer builds would
refuse to load images larger than 1 Mpixel.
This programming practice (which exists in other code bases as well)
is a by-product of having used early C compilers that did not properly
handle free(NULL). All modern compilers should properly handle that.
Fixes#398
... that caused some JPEG images with unusual sampling factors to be
misidentified as 4:4:4. This led to a buffer overflow when attempting
to decompress some such images using tjDecompressToYUV*().
Regression introduced by 479501b07c
The correct behavior is for the TurboJPEG API to refuse to decompress
such images, which it did prior to the aforementioned commit.
Fixes#389
If the TurboJPEG instance passed to tjDecodeYUV[Planes]() was previously
used to decompress a progressive JPEG image, then we need to disable the
progressive decompression parameters in the underlying libjpeg instance
before calling jinit_master_decompress().
This commit also modifies the build system so that the "tjtest" target
will test for this issue, and it corrects a previous oversight in the
build system whereby tjbenchtest did not test progressive
compression/decompression unless WITH_JAVA was true.
Prevent several integer overflow issues and subsequent segfaults that
occurred when attempting to compress or decompress gigapixel images with
the TurboJPEG API:
- Modify tjBufSize(), tjBufSizeYUV2(), and tjPlaneSizeYUV() to avoid
integer overflow when computing the return values and to return an
error if such an overflow is unavoidable.
- Modify tjunittest to validate the above.
- Modify tjCompress2(), tjEncodeYUVPlanes(), tjDecompress2(), and
tjDecodeYUVPlanes() to avoid integer overflow when computing the row
pointers in the 64-bit TurboJPEG C API.
- Modify TJBench (both C and Java versions) to avoid overflowing the
size argument to malloc()/new and to fail gracefully if such an
overflow is unavoidable.
In general, this allows gigapixel images to be accommodated by the
64-bit TurboJPEG C API when using automatic JPEG buffer (re)allocation.
Such images cannot currently be accommodated without automatic JPEG
buffer (re)allocation, due to the fact that tjAlloc() accepts a 32-bit
integer argument (oops.) Such images cannot be accommodated in the
TurboJPEG Java API due to the fact that Java always uses a signed 32-bit
integer as an array index.
Fixes#361
... including, but not limited to:
- unused macros
- private functions not marked as static
- unprototyped global functions
- variable shadowing
(detected by various non-default GCC 8 warning options)
Normally, 4:4:4 JPEGs have horizontal x vertical luminance & chrominance
sampling factors of 1x1. However, it is technically legal to create
4:4:4 JPEGs with sampling factors of 2x1, 1x2, 3x1, or 1x3, since the
sums of the products of those sampling factors are still <= 10. The
libjpeg API correctly decodes such images, so the TurboJPEG API should
as well.
Fixes#323
... in tjLoadImage()/tjSaveImage(). These error codes require an add-on
message table, and if it isn't initialized, then format_message()
produces "Bogus message code XXXX" instead.
Arguably it doesn't make much sense for non-chroma components to be
subsampled (which is why this type of image was overlooked in
cd7c3e6672cce3779450c6dd10d0d70b0c2278b2-- I didn't realize it was a
thing), but certain Adobe applications apparently generate these images.
Fixes#236
Within the libjpeg API code, it seems to be more the convention than not
to separate the macro name and value by two or more spaces, which
improves general readability. Making this consistent across all of
libjpeg-turbo is less about my individual preferences and more about
making it easy to automatically detect variations from our chosen
formatting convention. I intend to release the script I'm using to
validate this stuff, once it matures and stabilizes a bit.
* Modify the SIMD dispatchers so they guard their usage of getenv() with
the existing NO_GETENV preprocessor definition.
* Introduce a new NO_PUTENV preprocessor definition to guard the
usage of putenv() in the TurboJPEG API library.
This at least puts Windows Store compatibility within the realm of
possibility, although further steps are required.
Broken by previous commit. Although turbojpeg.c no longer needs
tjutil.h on Un*x, it still needs to include that file on Windows in
order to use snprintf() and strcasecmp() (which, on Windows, are macros
that wrap _snprintf_s() and stricmp().)
With rare exceptions ...
- Always separate line continuation characters by one space from
preceding code.
- Always use two-space indentation. Never use tabs.
- Always use K&R-style conditional blocks.
- Always surround operators with spaces, except in raw assembly code.
- Always put a space after, but not before, a comma.
- Never put a space between type casts and variables/function calls.
- Never put a space between the function name and the argument list in
function declarations and prototypes.
- Always surround braces ('{' and '}') with spaces.
- Always surround statements (if, for, else, catch, while, do, switch)
with spaces.
- Always attach pointer symbols ('*' and '**') to the variable or
function name.
- Always precede pointer symbols ('*' and '**') by a space in type
casts.
- Use the MIN() macro from jpegint.h within the libjpeg and TurboJPEG
API libraries (using min() from tjutil.h is still necessary for
TJBench.)
- Where it makes sense (particularly in the TurboJPEG code), put a blank
line after variable declaration blocks.
- Always separate statements in one-liners by two spaces.
The purpose of this was to ease maintenance on my part and also to make
it easier for contributors to figure out how to format patch
submissions. This was admittedly confusing (even to me sometimes) when
we had 3 or 4 different style conventions in the same source tree. The
new convention is more consistent with the formatting of other OSS code
bases.
This commit corrects deviations from the chosen formatting style in the
libjpeg API code and reformats the TurboJPEG API code such that it
conforms to the same standard.
NOTES:
- Although it is no longer necessary for the function name in function
declarations to begin in Column 1 (this was historically necessary
because of the ansi2knr utility, which allowed libjpeg to be built
with non-ANSI compilers), we retain that formatting for the libjpeg
code because it improves readability when using libjpeg's function
attribute macros (GLOBAL(), etc.)
- This reformatting project was accomplished with the help of AStyle and
Uncrustify, although neither was completely up to the task, and thus
a great deal of manual tweaking was required. Note to developers of
code formatting utilities: the libjpeg-turbo code base is an
excellent test bed, because AFAICT, it breaks every single one of the
utilities that are currently available.
- The legacy (MMX, SSE, 3DNow!) assembly code for i386 has been
formatted to match the SSE2 code (refer to
ff5685d5344273df321eb63a005eaae19d2496e3.) I hadn't intended to
bother with this, but the Loongson MMI implementation demonstrated
that there is still academic value to the MMX implementation, as an
algorithmic model for other 64-bit vector implementations. Thus, it
is desirable to improve its readability in the same manner as that of
the SSE2 implementation.
The main justification for this is to provide new libjpeg-turbo users
with a quick & easy way of developing a complete JPEG
compression/decompression program without requiring them to build
libjpeg-turbo from source (which was necessary in order to use the
project-private bmp API) or to use external libraries. These new
functions build upon significant enhancements to rdbmp.c, wrbmp.c,
rdppm.c, and wrppm.c which allow those engines to convert directly
between the native pixel format of the file and a pixel format
("colorspace" in libjpeg parlance) specified by the calling program.
rdbmp.c and wrbmp.c have also been modified such that the calling
program can choose to read or write image rows in the native (bottom-up)
order of the file format, thus eliminating the need to use an inversion
array. tjLoadImage() and tjSaveImage() leverage these new underlying
features in order to significantly improve upon the performance of the
old bmp API.
Because these new functions cannot work without the libjpeg-turbo
colorspace extensions, the libjpeg-compatible code in turbojpeg.c has
been removed. That code was only there to serve as an example of how
to use the TurboJPEG API on top of libjpeg, but more specific, buildable
examples now exist in the https://github.com/libjpeg-turbo/ijg
repository.
Allow progressive entropy coding to be enabled on a
transform-by-transform basis, and implement a new transform option for
disabling the copying of markers.
Closes#153
- Provide a new C API function and TJException method that allows
calling programs to query the severity of a compression/decompression/
transform error.
- Provide a new flag that instructs the library to immediately stop
compressing/decompressing/transforming if a warning is encountered.
Fixes#151
Introduce a new C API function (tjGetErrorStr2()) that can be used to
retrieve compression/decompression/transform error messages in a
thread-safe (i.e. instance-specific) manner. Retrieving error messages
from global functions is still thread-unsafe.
Addresses a concern expressed in #151.
Referring to https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=746,
it seems that the values of local buffer pointers in TurboJPEG API
functions aren't always preserved if longjmp() returns control to a
point prior to the allocation of the local buffers. This is known to
be an issue with GCC 4.x and clang with -O1 and higher optimization
levels but not with GCC 5.x and later. It is unknown why GCC 5.x and
6.x do not suffer from the issue, but possibly the local buffer pointers
are not allocated on the stack when using those more recent compilers.
In any case, this commit modifies the TurboJPEG API library code such
that the jump buffer is always updated after any local buffer pointers
are allocated but before any subsequent libjpeg API functions are
called.
Normally, 4:2:2 JPEGs have horizontal x vertical luminance,chrominance
sampling factors of 2x1,1x1, and 4:4:0 JPEGs have horizontal x vertical
luminance,chrominance sampling factors of 1x2,1x1. However, it is
technically legal to create 4:2:2 JPEGs with sampling factors of
2x2,1x2 and 4:4:0 JPEGs with sampling factors of 2x2,2x1, since the
sums of the products of those sampling factors (2x2 + 1x2 + 1x2 and
2x2 + 2x1 + 2x1) are still <= 10. The libjpeg API correctly decodes
such images, so the TurboJPEG API should as well.
Fixes#92
