jchuff.c


Log

Author Commit Date CI Message
DRC 1ed312ea 2020-10-15T17:47:31 "ARM"="Arm", "NEON"="Neon" Refer to: https://www.arm.com/company/policies/trademarks/arm-trademark-list/arm-trademark https://www.arm.com/company/policies/trademarks/arm-trademark-list/neon-trademark NOTE: These changes are only applied to change log entries for 2.0.x and later, since the change log is a historical record and Arm's new trademark policy did not go into effect until late 2017.
DRC c76f4a08 2019-12-05T13:12:28 Huffman enc.: Fix very rare local buffer overrun ... detected by ASan. This is a similar issue to the issue that was fixed with 402a715f82313384ef4606660c32d8678c79f197. Apparently it is possible to create a malformed JPEG image that exceeds the Huffman encoder's 256-byte local buffer when attempting to losslessly tranform the image. That makes sense, given that it was necessary to extend the Huffman decoder's local buffer to 512 bytes in order to handle all pathological cases (refer to 0463f7c9aad060fcd56e98d025ce16185279e2bc.) Since this issue affected only lossless transformation, a workflow that isn't generally exposed to arbitrary data exploits, and since the overrun did not overflow the stack (i.e. it did not result in a segfault or other user-visible issue, and valgrind didn't even detect it), it did not likely pose a security risk. Fixes #392
DRC 74aeaddf 2019-10-16T21:16:43 jc*huff.c: Consistify preproc directive formatting The rest of the libjpeg API code uses "#if defined(condition)" rather than "#if defined condition".
DRC 6399d0a6 2019-04-23T14:10:04 Fix code formatting/style issues ... ... 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)
DRC a6289526 2018-07-24T18:36:51 Fix JPEG spec references per ISO/ITU-T suggestions - 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.
DRC 293263c3 2018-03-17T15:14:35 Format preprocessor macros more consistently 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.
DRC 19c791cd 2018-03-08T10:55:20 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.
DRC 123f7258 2016-05-24T10:23:56 Format copyright headers more consistently 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.)
DRC f76c01d0 2016-02-19T10:56:13 Use consistent/modern code formatting for dbl ptrs
DRC bd49803f 2016-02-19T08:53:33 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.
Guido Vollbeding fc11193e 2014-01-19T00:00:00 The Independent JPEG Group's JPEG software v9a
DRC f3a8684c 2016-01-07T00:19:43 SSE2 SIMD implementation of Huffman encoding Full-color compression speedups relative to libjpeg-turbo 1.4.2: 2.8 GHz Intel Xeon W3530, Linux, 64-bit: 2.2-18% (avg. 9.5%) 2.8 GHz Intel Xeon W3530, Linux, 32-bit: 10-25% (avg. 17%) 2.3 GHz AMD A10-4600M APU, Linux, 64-bit: 4.9-17% (avg. 11%) 2.3 GHz AMD A10-4600M APU, Linux, 32-bit: 8.8-19% (avg. 15%) 3.0 GHz Intel Core i7, OS X, 64-bit: 3.5-16% (avg. 10%) 3.0 GHz Intel Core i7, OS X, 32-bit: 4.8-14% (avg. 11%) 2.6 GHz AMD Athlon 64 X2 5050e: Performance-neutral (give or take a few percent) Full-color compression speedups relative to IPP: 2.8 GHz Intel Xeon W3530, Linux, 64-bit: 4.8-34% (avg. 19%) 2.8 GHz Intel Xeon W3530, Linux, 32-bit: -19%-7.0% (avg. -7.0%) Refer to #42 for discussion. Numerous other approaches were attempted, but this one proved to be the most performant across all platforms. This commit also fixes #3 (works around, really-- the clang-compiled version of jchuff.c still performs 20% worse than its GCC-compiled counterpart, but that code is now bypassed by the new SSE2 Huffman algorithm.) Based on: https://github.com/mayeut/libjpeg-turbo/commit/2cb4d41330e1edc4469f6b97ba73b73abfbeb02f https://github.com/mayeut/libjpeg-turbo/commit/36c94e050d117912adbff9fbcc6fe307df240168
DRC 2111c5ac 2016-01-06T19:24:55 Merge branch '1.4.x'
DRC 5a3b4fed 2016-01-06T19:17:54 Regression: Allow co-install of 32-bit/64-bit RPMs Fix a regression introduced in 1.4.1 that prevented 32-bit and 64-bit libjpeg-turbo RPMs from being installed simultaneously on recent Red Hat/Fedora distributions. This was due to the addition of the SIZEOF_SIZE_T macro in jconfig.h, which allows the Huffman codec to determine the word size at compile time. Since that macro differs between 32-bit and 64-bit builds, this caused a conflict between the i386 and x86_64 RPMs (any differing files, other than executables, are not allowed when 32-bit and 64-bit RPMs are installed simultaneously.) Since the macro is used only internally, it has been moved into jconfigint.h.
DRC 1e32fe31 2015-10-14T17:32:39 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.
DRC 7e3acc0e 2015-10-10T10:25:46 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.
Thomas G. Lane 489583f5 1996-02-07T00:00:00 The Independent JPEG Group's JPEG software v6a
Thomas G. Lane bc79e068 1995-08-02T00:00:00 The Independent JPEG Group's JPEG software v6
Thomas G. Lane 36a4cccc 1994-09-24T00:00:00 The Independent JPEG Group's JPEG software v5
Thomas G. Lane cc7150e2 1993-02-18T00:00:00 The Independent JPEG Group's JPEG software v4a
Thomas G. Lane 88aeed42 1992-12-10T00:00:00 The Independent JPEG Group's JPEG software v4
Thomas G. Lane 4a6b7303 1992-03-17T00:00:00 The Independent JPEG Group's JPEG software v3
Thomas G. Lane bd543f03 1991-12-13T00:00:00 The Independent JPEG Group's JPEG software v2
Thomas G. Lane 2cbeb8ab 1991-10-07T00:00:00 The Independent JPEG Group's JPEG software v1
Guido Vollbeding 989630f7 2010-01-10T00:00:00 The Independent JPEG Group's JPEG software v8
Guido Vollbeding 5996a25e 2009-06-27T00:00:00 The Independent JPEG Group's JPEG software v7
Thomas G. Lane 5ead57a3 1998-03-27T00:00:00 The Independent JPEG Group's JPEG software v6b
DRC 3ebcc320 2015-05-15T19:09:44 __WORDSIZE doesn't seem to be available on platforms other than Mac or Linux, and best practices are for user-level code not to rely on it anyhow, since it's meant to be an internal macro. Fortunately, autoconf already has a way of determining the word size at configure time, so it can be passed into the compiler. This should work on any platform and has been tested on all of the Un*x platforms we support (Linux, Mac, FreeBSD, Solaris.) git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.4.x@1550 632fc199-4ca6-4c93-a231-07263d6284db
DRC a8b6ea2f 2015-05-06T22:41:12 Fix a bug in the 64-bit Huffman encoder that Google discovered when encoding some very specific (and proprietary) aerial images using quality=98, an optimized Huffman table, and the ISLOW DCT. These images were causing the Huffman bit buffer to overflow, because the code for encoding the DC coefficient was using the equivalent of the 32-bit version of EMIT_BITS(). Thus, when 64-bit code was used, the DC coefficient code was not properly checking how many bits were in the buffer before attempting to add more bits to it. This issue appears to have existed in all versions of libjpeg-turbo. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.4.x@1547 632fc199-4ca6-4c93-a231-07263d6284db
DRC 96869f4b 2015-04-30T09:05:53 Restore backward compatibility with MSVC < 2010 (broken by r1541) git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.4.x@1543 632fc199-4ca6-4c93-a231-07263d6284db
DRC f64b36fd 2015-04-22T08:43:04 Oops. OS X doesn't define __WORDSIZE unless you include stdint.h, so apparently the Huffman codec hasn't ever been fully accelerated on 64-bit OS X. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.4.x@1541 632fc199-4ca6-4c93-a231-07263d6284db
DRC bb383b41 2014-11-22T22:24:41 Fix Huffman local buffer overrun discovered by Debian developers when attempting to transform a junk image using ImageMagick: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=768369 git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.3.x@1427 632fc199-4ca6-4c93-a231-07263d6284db
DRC 402a715f 2014-11-22T22:09:30 Fix Huffman local buffer overrun discovered by Debian developers when attempting to transform a junk image using ImageMagick: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=768369 git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.4.x@1426 632fc199-4ca6-4c93-a231-07263d6284db
DRC 803b5d24 2014-11-18T15:56:43 Uses clz and bsr instructions for bit counting on ARM64 platforms as well. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.4.x@1414 632fc199-4ca6-4c93-a231-07263d6284db
DRC 2261e1e4 2014-08-21T03:40:37 Actually, we need to increase the size of BUFSIZE, not just the size of _buffer. The previous patch might have cause problems if, for instance, state->free_in_buffer was 127 but 129 bytes were compressed. In that case, only 127 of the 129 bytes would have been written to the file. Also document the fix. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1367 632fc199-4ca6-4c93-a231-07263d6284db
DRC eddc355d 2014-08-21T03:38:14 Actually, we need to increase the size of BUFSIZE, not just the size of _buffer. The previous patch might have cause problems if, for instance, state->free_in_buffer was 127 but 129 bytes were compressed. In that case, only 127 of the 129 bytes would have been written to the file. Also document the fix. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.3.x@1366 632fc199-4ca6-4c93-a231-07263d6284db
DRC 29823fa9 2014-08-21T01:55:22 Fix an extremely rare crash that can occur when compressing a very high-frequency MCU using quality 100 and no subsampling, and when dynamically allocating the JPEG buffer in the destination manager. Even with a test program designed specifically to reproduce the crash, it only occurred once in about 25 million iterations. More details here: https://sourceforge.net/p/libjpeg-turbo/bugs/64 git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.3.x@1365 632fc199-4ca6-4c93-a231-07263d6284db
DRC 9c168ad2 2014-08-21T01:53:47 Fix an extremely rare crash that can occur when compressing a very high-frequency MCU using quality 100 and no subsampling, and when dynamically allocating the JPEG buffer in the destination manager. Even with a test program designed specifically to reproduce the crash, it only occurred once in about 25 million iterations. More details here: https://sourceforge.net/p/libjpeg-turbo/bugs/64 git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1364 632fc199-4ca6-4c93-a231-07263d6284db
DRC 5de454b2 2014-05-18T19:04:03 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
DRC bc56b754 2014-05-16T10:43:44 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
DRC b7753510 2014-05-11T09:36:25 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
DRC e5eaf374 2014-05-09T18:00:32 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
DRC ef9a4e05 2014-03-28T18:50:30 Integrate a slightly modified version of Mozilla's patch for precomputing the bit-counting LUT. This is useful if the table needs to be shared among multiple processes, although the primary reason for doing that is reduced footprint on mobile devices, which are probably already covered by the clz intrinsic code. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1221 632fc199-4ca6-4c93-a231-07263d6284db
DRC 0cfc4c17 2014-03-28T18:33:25 Use clz/bsr instructions on ARM for bit counting rather than the lookup table (reduces memory footprint and can improve performance in some cases.) git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1220 632fc199-4ca6-4c93-a231-07263d6284db
DRC a6ef282a 2013-09-28T03:23:49 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
DRC ba923a85 2013-09-24T03:26:47 Fix I/O suspension. This little nugget of code was introduced in r30 as part of an early attempt to make buffered I/O work with the optimized Huffman codec. Ultimately, r32 reverted a lot of that mess and introduced much of the logic we now use, rendering this code unnecessary, but it was never reverted because it only causes problems when I/O suspension is used, and apparently no one has tried to do that with libjpeg-turbo until now. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.2.x@1033 632fc199-4ca6-4c93-a231-07263d6284db
DRC a73e870a 2012-12-31T02:52:30 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
DRC ac906c53 2011-05-26T11:28:22 Change the name of the pre-computed bits table to match its actual function git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@653 632fc199-4ca6-4c93-a231-07263d6284db
DRC 6bb57b72 2011-04-26T22:08:31 Re-factor and re-license under the libjpeg BSD-style license. Justification: the accelerated Huffman encoding optimizations in libjpeg-turbo were all developed by me as an independent developer. The structure of the inline Huffman encoding macros was originally borrowed from similar routines in the TurboJPEG/mediaLib codec, which is part of VirtualGL and TurboVNC. Thus, although the code for these macros was not copied verbatim, they were still thought to be a derivative work of TurboJPEG/mediaLib, and I assigned the copyright and license from TurboJPEG/mediaLib to them. I have re-written these routines from first principles by breaking down the libjpeg out-of-line routines. Although the new code bears algorithmic similarities to the TurboJPEG/mediaLib macros, it can now clearly be shown to be derived from the out-of-line routines and thus, in my opinion, it can no longer be considered a derivative of TurboJPEG/mediaLib. -- DRC git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@597 632fc199-4ca6-4c93-a231-07263d6284db
DRC a46830b2 2010-11-23T18:00:46 Eliminate spurious global symbols git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@303 632fc199-4ca6-4c93-a231-07263d6284db
DRC 830d5fcc 2010-04-20T21:13:26 Use 64-bit holding buffer on Win64 for increased performance git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@177 632fc199-4ca6-4c93-a231-07263d6284db
DRC 04899094 2010-02-26T23:01:19 Bleepin' Windows uses LLP64, not LP64 git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@158 632fc199-4ca6-4c93-a231-07263d6284db
DRC dae44741 2009-08-06T08:58:48 Unfortunately, the previous enhancements made an invalid assumption about the code sizes, which caused "DCT out of range" errors in the decoder. Was able to fix 64-bit without losing any performance, but unfortunately had to revert 32-bit back to its previous behavior for now. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@58 632fc199-4ca6-4c93-a231-07263d6284db
DRC 8443e529 2009-07-30T08:35:06 Improve compression performance by 15-20% git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@55 632fc199-4ca6-4c93-a231-07263d6284db
DRC 3cba8db0 2009-03-16T23:58:30 Eliminate backward incompatibility that required empty_output_buffer() to handle cases in which the buffer wasn't 100% full git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@32 632fc199-4ca6-4c93-a231-07263d6284db
DRC 86299887 2009-03-14T01:21:13 Fix broken buffered I/O (to make cjpeg work) git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@30 632fc199-4ca6-4c93-a231-07263d6284db
DRC 99313388 2009-03-12T17:24:27 Include Huffman codec optimizations borrowed from TurboJPEG git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@24 632fc199-4ca6-4c93-a231-07263d6284db
Constantin Kaplinsky 0ca44258 2008-09-28T05:08:48 Merged changes from branches/1.5-xserver (revision range 2432:2631) back to trunk. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@2 632fc199-4ca6-4c93-a231-07263d6284db