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e8b40f3c
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2022-11-01T21:45:39
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Vastly improve 12-bit JPEG integration
The Gordian knot that 7fec5074f962b20ed00b4f5da4533e1e8d4ed8ac attempted
to unravel was caused by the fact that there are several
data-precision-dependent (JSAMPLE-dependent) fields and methods in the
exposed libjpeg API structures, and if you change the exposed libjpeg
API structures, then you have to change the whole API. If you change
the whole API, then you have to provide a whole new library to support
the new API, and that makes it difficult to support multiple data
precisions in the same application. (It is not impossible, as example.c
demonstrated, but using data-precision-dependent libjpeg API structures
would have made the cjpeg, djpeg, and jpegtran source code hard to read,
so it made more sense to build, install, and package 12-bit-specific
versions of those applications.)
Unfortunately, the result of that initial integration effort was an
unreadable and unmaintainable mess, which is a problem for a library
that is an ISO/ITU-T reference implementation. Also, as I dug into the
problem of lossless JPEG support, I realized that 16-bit lossless JPEG
images are a thing, and supporting yet another version of the libjpeg
API just for those images is untenable.
In fact, however, the touch points for JSAMPLE in the exposed libjpeg
API structures are minimal:
- The colormap and sample_range_limit fields in jpeg_decompress_struct
- The alloc_sarray() and access_virt_sarray() methods in
jpeg_memory_mgr
- jpeg_write_scanlines() and jpeg_write_raw_data()
- jpeg_read_scanlines() and jpeg_read_raw_data()
- jpeg_skip_scanlines() and jpeg_crop_scanline()
(This is subtle, but both of those functions use JSAMPLE-dependent
opaque structures behind the scenes.)
It is much more readable and maintainable to provide 12-bit-specific
versions of those six top-level API functions and to document that the
aforementioned methods and fields must be type-cast when using 12-bit
samples. Since that eliminates the need to provide a 12-bit-specific
version of the exposed libjpeg API structures, we can:
- Compile only the precision-dependent libjpeg modules (the
coefficient buffer controllers, the colorspace converters, the
DCT/IDCT managers, the main buffer controllers, the preprocessing
and postprocessing controller, the downsampler and upsamplers, the
quantizers, the integer DCT methods, and the IDCT methods) for
multiple data precisions.
- Introduce 12-bit-specific methods into the various internal
structures defined in jpegint.h.
- Create precision-independent data type, macro, method, field, and
function names that are prefixed by an underscore, and use an
internal header to convert those into precision-dependent data
type, macro, method, field, and function names, based on the value
of BITS_IN_JSAMPLE, when compiling the precision-dependent libjpeg
modules.
- Expose precision-dependent jinit*() functions for each of the
precision-dependent libjpeg modules.
- Abstract the precision-dependent libjpeg modules by calling the
appropriate precision-dependent jinit*() function, based on the
value of cinfo->data_precision, from top-level libjpeg API
functions.
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2e136a71
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2022-08-08T14:17:51
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Re-fix buf img mode decompr err w/short prog JPEGs
This commit reverts 4dbc293125b417f97e5b1ca9e7260c82ff199a06 and
9f8f683e745972720433406cff4b31e95bd6a33e (the previous two commits) and
fixes #613 the correct way. The crux of the issue wasn't the size of
the whole_image virtual array but rather that, since last_iMCU_row is
unsigned, (last_iMCU_row - 1) wrapped around to 0xFFFFFFFF when
last_iMCU_row was 0. This caused the interblock smoothing algorithm
introduced in 6d91e950c871103a11bac2f10c63bf998796c719 to erroneously
try to access the next two iMCU rows, neither of which existed. The
first attempt at a fix (4dbc293125b417f97e5b1ca9e7260c82ff199a06)
exposed a NULL dereference, detected by OSS-Fuzz, that occurred when
attempting to decompress a specially-crafted malformed JPEG image to a
YUV buffer using tjDecompressToYUV*() with 1/4 IDCT scaling.
Fixes #613 (again)
Also fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=49898
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9f8f683e
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2022-08-07T14:15:03
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jdcoefct.c: Fix signed/unsigned mismatch VC++ wrng
(introduced by previous commit)
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4dbc2931
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2022-08-07T09:24:57
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Fix buf image mode decompr err w/ short prog JPEGs
Regression introduced by 6d91e950c871103a11bac2f10c63bf998796c719
Because we're now using a 5x5 smoothing window when decompressing
progressive JPEG images, we need to ensure that the whole_image virtual
array contains at least five rows. Previously that was not always the
case unless the progressive JPEG image being decompressed had at least
five iMCU rows. Since an iMCU has a height of (8 * the vertical
sampling factor), attempting to decompress 4:2:2 and 4:4:4 images <= 32
pixels in height or 4:2:0 images <= 64 pixels in height triggered a
JERR_BAD_VIRTUAL_ACCESS error in decompress_smooth_data(), because
access_rows exceeded the number of rows in the virtual array.
Fixes #613
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c7ca521b
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2020-11-28T06:38:27
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Fix uninitialized read in decompress_smooth_data()
Regression introduced by 42825b68d570fb07fe820ac62ad91017e61e9a25
Referring to the discussion in #459, the OSS-Fuzz test case
https://github.com/libjpeg-turbo/libjpeg-turbo/files/5597075/clusterfuzz-testcase-minimized-pngsave_buffer_fuzzer-5728375846731776.txt
created a situation in which
cinfo->output_iMCU_row > cinfo->master->last_good_iMCU_row
but
cinfo->input_scan_number == 1
thus causing decompress_smooth_data() to read from
prev_coef_bits_latch[], which was uninitialized. I was unable to create
the same situation with a real JPEG image.
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ccaba5d7
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2020-11-25T14:55:55
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Fix buffer overrun with certain narrow prog JPEGs
Regression introduced by 6d91e950c871103a11bac2f10c63bf998796c719
last_block_column in decompress_smooth_data() can be 0 if, for instance,
decompressing a 4:4:4 image of width 8 or less or a 4:2:2 or 4:2:0 image
of width 16 or less. Since last_block_column is an unsigned int,
subtracting 1 from it produced 0xFFFFFFFF, the test in line 590 passed,
and we attempted to access blocks from a second block column that didn't
actually exist.
Closes #476
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6d91e950
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2020-10-05T13:37:44
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Use 5x5 win & 9 AC coeffs when smoothing DC scans
... of progressive images.
Based on:
https://github.com/mo271/libjpeg-turbo/commit/be8d36d13b79a472e56da0717ba067e6139bc0e1
https://github.com/mo271/libjpeg-turbo/commit/9d528f278ee3a5ba571c0b9ec4567c557614fb25
https://github.com/mo271/libjpeg-turbo/commit/85f36f0765ea2c28909fc4c0e570cd68d3a1ed85
https://github.com/mo271/libjpeg-turbo/commit/63a4d39e387f61bcb83b393838f436b410b97308
https://github.com/mo271/libjpeg-turbo/commit/51336a6ad5acb9379dc8e3e5e5758fd439224b7c
Closes #459
Closes #474
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8789a5e2
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2020-10-01T21:27:47
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Merge branch 'master' into dev
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2ec4a5eb
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2020-10-01T19:18:44
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Fix dec artifacts w/cropped+smoothed prog DC scans
This commit modifies decompress_smooth_data(), adding missing MCU column
offsets to the prev_block_row and next_block_row indices that are used
for block rows other than the first and last. Effectively, this
eliminates unexpected visual artifacts when using jpeg_crop_scanline()
along with interblock smoothing while decompressing the DC scan of a
progressive JPEG image.
Based on:
https://github.com/mo271/libjpeg-turbo/commit/0227d4fb484e6baf1565163211ee64e52e7b96bd
Fixes #456
Closes #457
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42825b68
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2019-11-07T14:03:23
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Fault-tolerant multi-scan block smoothing
This commit modifies the behavior of the block smoothing algorithm in
the libjpeg API library so that, if a scan in a multi-scan JPEG image is
incomplete (due to premature termination of the image stream), the block
smoothing parameters from the previous (complete) scan are used to
smooth any iMCU rows that the incomplete scan does not contain.
Closes #343
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19c791cd
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2018-03-08T10:55:20
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Improve code formatting consistency
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.
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3ab68cf5
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2016-02-19T18:32:10
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libjpeg API: Partial scanline decompression
This, in combination with the existing jpeg_skip_scanlines() function,
provides the ability to crop the image both horizontally and vertically
while decompressing (certain restrictions apply-- see libjpeg.txt.)
This also cleans up the documentation of the line skipping feature and
removes the "strip decompression" feature from djpeg, since the new
cropping feature is a superset of it.
Refer to #34 for discussion.
Closes #34
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bd49803f
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2016-02-19T08:53:33
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Use consistent/modern code formatting for pointers
The convention used by libjpeg:
type * variable;
is not very common anymore, because it looks too much like
multiplication. Some (particularly C++ programmers) prefer to tuck the
pointer symbol against the type:
type* variable;
to emphasize that a pointer to a type is effectively a new type.
However, this can also be confusing, since defining multiple variables
on the same line would not work properly:
type* variable1, variable2; /* Only variable1 is actually a
pointer. */
This commit reformats the entirety of the libjpeg-turbo code base so
that it uses the same code formatting convention for pointers that the
TurboJPEG API code uses:
type *variable1, *variable2;
This seems to be the most common convention among C programmers, and
it is the convention used by other codec libraries, such as libpng and
libtiff.
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ce0dd949
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2016-02-06T12:18:44
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Fix MinGW build
jinclude.h can't be safely included multiple times, so instead of
including it in the shared (broken-out) headers, it should instead be
included by the source files that include one or more of those headers.
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1e32fe31
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2015-10-14T17:32:39
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Replace INT32 with a new internal datatype (JLONG)
These days, INT32 is a commonly-defined datatype in system headers. We
cannot eliminate the definition of that datatype from jmorecfg.h, since
the INT32 typedef has technically been part of the libjpeg API since
version 5 (1994.) However, using INT32 internally is risky, because the
inclusion of a particular header (Xmd.h, for instance) could change the
definition of INT32 from long to int on 64-bit platforms and thus change
the internal behavior of libjpeg-turbo in unexpected ways (for instance,
failing to correctly set __INT32_IS_ACTUALLY_LONG to match the INT32
typedef-- perhaps as a result of including the wrong version of
jpeglib.h-- could cause libjpeg-turbo to produce incorrect results.)
The library has always been built in environments in which INT32 is
effectively long (on Windows, long is always 32-bit, so effectively it's
the same as int), so it makes sense to turn INT32 into an explicitly
long datatype. This ensures that libjpeg-turbo will always behave
consistently, regardless of the headers included at compile time.
Addresses a concern expressed in #26.
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7e3acc0e
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2015-10-10T10:25:46
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Rename README, LICENSE, BUILDING text files
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.
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a2e6a9dd
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2006-02-04T00:00:00
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IJG R6b with x86SIMD V1.02
Independent JPEG Group's JPEG software release 6b
with x86 SIMD extension for IJG JPEG library version 1.02
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489583f5
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1996-02-07T00:00:00
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The Independent JPEG Group's JPEG software v6a
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bc79e068
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1995-08-02T00:00:00
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The Independent JPEG Group's JPEG software v6
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a8b67c4f
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1995-03-15T00:00:00
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The Independent JPEG Group's JPEG software v5b
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36a4cccc
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1994-09-24T00:00:00
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The Independent JPEG Group's JPEG software v5
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5829cb23
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2012-01-15T00:00:00
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The Independent JPEG Group's JPEG software v8d
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5996a25e
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2009-06-27T00:00:00
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The Independent JPEG Group's JPEG software v7
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5ead57a3
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1998-03-27T00:00:00
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The Independent JPEG Group's JPEG software v6b
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eb32cc1e
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2015-06-25T03:44:36
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Add a new libjpeg API function (jpeg_skip_scanlines()) to allow for partially decoding a JPEG image.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1582 632fc199-4ca6-4c93-a231-07263d6284db
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5de454b2
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2014-05-18T19:04:03
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libjpeg-turbo has never supported non-ANSI compilers, so get rid of the crufty SIZEOF() macro. It was not being used consistently anyhow, so it would not have been possible to build prior releases of libjpeg-turbo using the broken compilers for which that macro was designed.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1313 632fc199-4ca6-4c93-a231-07263d6284db
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5033f3e1
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2014-05-18T18:33:44
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Remove MS-DOS code and information, and adjust copyright headers to reflect the removal of features in r1307 and r1308. libjpeg-turbo has never supported MS-DOS, nor is it even possible for us to do so.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1312 632fc199-4ca6-4c93-a231-07263d6284db
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bc56b754
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2014-05-16T10:43:44
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Get rid of the HAVE_PROTOTYPES configuration option, as well as the related JMETHOD and JPP macros. libjpeg-turbo has never supported compilers that don't handle prototypes. Doing so requires ansi2knr, which isn't even supported in the IJG code anymore.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1308 632fc199-4ca6-4c93-a231-07263d6284db
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b7753510
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2014-05-11T09:36:25
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Convert tabs to spaces in the libjpeg code and the SIMD code (TurboJPEG retains the use of tabs for historical reasons. They were annoying in the libjpeg code primarily because they were not consistently used and because they were used to format as well as indent the code. In the case of TurboJPEG, tabs are used just to indent the code, so even if the editor assumes a different tab width, the code will still be readable.)
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.3.x@1285 632fc199-4ca6-4c93-a231-07263d6284db
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e5eaf374
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2014-05-09T18:00:32
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Convert tabs to spaces in the libjpeg code and the SIMD code (TurboJPEG retains the use of tabs for historical reasons. They were annoying in the libjpeg code primarily because they were not consistently used and because they were used to format as well as indent the code. In the case of TurboJPEG, tabs are used just to indent the code, so even if the editor assumes a different tab width, the code will still be readable.)
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1278 632fc199-4ca6-4c93-a231-07263d6284db
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a6ef282a
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2013-09-28T03:23:49
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Some of the IJG headers say "Modified by", so clarify that our "Modifications" are not referring to these.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.3.x@1053 632fc199-4ca6-4c93-a231-07263d6284db
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a73e870a
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2012-12-31T02:52:30
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Change the copyright notices to make it clear that our modified files are not part of the IJG's software.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.2.x@873 632fc199-4ca6-4c93-a231-07263d6284db
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49967cdb
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2010-10-09T19:57:51
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Improve readability and flexibility of compatibility macros
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@241 632fc199-4ca6-4c93-a231-07263d6284db
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36a6eec9
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2010-10-08T08:05:44
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Added optional emulation of the jpeg-7 or jpeg-8b API/ABI's
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@236 632fc199-4ca6-4c93-a231-07263d6284db
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35c47196
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2009-03-09T13:29:37
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Make sure the work space memory is properly aligned
We use the heap allocators to avoid having more than one implementation
of the alignment logic.
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@19 632fc199-4ca6-4c93-a231-07263d6284db
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