jdhuff.c


Log

Author Commit Date CI Message
DRC af618ffe 2022-11-08T15:01:18 Clean up the lossless JPEG feature - Rename jpeg_simple_lossless() to jpeg_enable_lossless() and modify the function so that it stores the lossless parameters directly in the Ss and Al fields of jpeg_compress_struct rather than using a scan script. - Move the cjpeg -lossless switch into "Switches for advanced users". - Document the libjpeg API and run-time features that are unavailable in lossless mode, and ensure that all parameters, functions, and switches related to unavailable features are ignored or generate errors in lossless mode. - Defer any action that depends on whether lossless mode is enabled until jpeg_start_compress()/jpeg_start_decompress() is called. - Document the purpose of the point transform value. - "Codec" stands for coder/decoder, so it is a bit awkward to say "lossless compression codec" and "lossless decompression codec". Use "lossless compressor" and "lossless decompressor" instead. - Restore backward API/ABI compatibility with libjpeg v6b: * Move the new 'lossless' field from the exposed jpeg_compress_struct and jpeg_decompress_struct structures into the opaque jpeg_comp_master and jpeg_decomp_master structures, and allocate the master structures in the body of jpeg_create_compress() and jpeg_create_decompress(). * Remove the new 'process' field from jpeg_compress_struct and jpeg_decompress_struct and replace it with the old 'progressive_mode' field and the new 'lossless' field. * Remove the new 'data_unit' field from jpeg_compress_struct and jpeg_decompress_struct and replace it with a locally-computed data unit variable. * Restore the names of macros and fields that refer to DCT blocks, and document that they have a different meaning in lossless mode. (Most of them aren't very meaningful in lossless mode anyhow.) * Remove the new alloc_darray() method from jpeg_memory_mgr and replace it with an internal macro that wraps the alloc_sarray() method. * Move the JDIFF* data types from jpeglib.h and jmorecfg.h into jpegint.h. * Remove the new 'codec' field from jpeg_compress_struct and jpeg_decompress_struct and instead reuse the existing internal coefficient control, forward/inverse DCT, and entropy encoding/decoding structures for lossless compression/decompression. * Repurpose existing error codes rather than introducing new ones. (The new JERR_BAD_RESTART and JWRN_MUST_DOWNSCALE codes remain, although JWRN_MUST_DOWNSCALE will probably be removed in libjpeg-turbo, since we have a different way of handling multiple data precisions.) - Automatically enable lossless mode when a scan script with parameters that are only valid for lossless mode is detected, and document the use of scan scripts to generate lossless JPEG images. - Move the sequential and shared Huffman routines back into jchuff.c and jdhuff.c, and document that those routines are shared with jclhuff.c and jdlhuff.c as well as with jcphuff.c and jdphuff.c. - Move MAX_DIFF_BITS from jchuff.h into jclhuff.c, the only place where it is used. - Move the predictor and scaler code into jclossls.c and jdlossls.c. - Streamline register usage in the [un]differencers (inspired by similar optimizations in the color [de]converters.) - Restructure the logic in a few places to reduce duplicated code. - Ensure that all lossless-specific code is guarded by C_LOSSLESS_SUPPORTED or D_LOSSLESS_SUPPORTED and that the library can be built successfully if either or both of those macros is undefined. - Remove all short forms of external names introduced by the lossless JPEG patch. (These will not be needed by libjpeg-turbo, so there is no use cleaning them up.) - Various wordsmithing, formatting, and punctuation tweaks - Eliminate various compiler warnings.
DRC b56e8b28 2022-11-08T15:01:18 Clean up the lossless JPEG feature - Rename jpeg_simple_lossless() to jpeg_enable_lossless() and modify the function so that it stores the lossless parameters directly in the Ss and Al fields of jpeg_compress_struct rather than using a scan script. - Move the cjpeg -lossless switch into "Switches for advanced users". - Document the libjpeg API and run-time features that are unavailable in lossless mode, and ensure that all parameters, functions, and switches related to unavailable features are ignored or generate errors in lossless mode. - Defer any action that depends on whether lossless mode is enabled until jpeg_start_compress()/jpeg_start_decompress() is called. - Document the purpose of the point transform value. - "Codec" stands for coder/decoder, so it is a bit awkward to say "lossless compression codec" and "lossless decompression codec". Use "lossless compressor" and "lossless decompressor" instead. - Restore backward API/ABI compatibility with libjpeg v6b: * Move the new 'lossless' field from the exposed jpeg_compress_struct and jpeg_decompress_struct structures into the opaque jpeg_comp_master and jpeg_decomp_master structures, and allocate the master structures in the body of jpeg_create_compress() and jpeg_create_decompress(). * Remove the new 'process' field from jpeg_compress_struct and jpeg_decompress_struct and replace it with the old 'progressive_mode' field and the new 'lossless' field. * Remove the new 'data_unit' field from jpeg_compress_struct and jpeg_decompress_struct and replace it with a locally-computed data unit variable. * Restore the names of macros and fields that refer to DCT blocks, and document that they have a different meaning in lossless mode. (Most of them aren't very meaningful in lossless mode anyhow.) * Remove the new alloc_darray() method from jpeg_memory_mgr and replace it with an internal macro that wraps the alloc_sarray() method. * Move the JDIFF* data types from jpeglib.h and jmorecfg.h into jpegint.h. * Remove the new 'codec' field from jpeg_compress_struct and jpeg_decompress_struct and instead reuse the existing internal coefficient control, forward/inverse DCT, and entropy encoding/decoding structures for lossless compression/decompression. * Repurpose existing error codes rather than introducing new ones. (The new JERR_BAD_RESTART and JWRN_MUST_DOWNSCALE codes remain, although JWRN_MUST_DOWNSCALE will probably be removed in libjpeg-turbo, since we have a different way of handling multiple data precisions.) - Automatically enable lossless mode when a scan script with parameters that are only valid for lossless mode is detected, and document the use of scan scripts to generate lossless JPEG images. - Move the sequential and shared Huffman routines back into jchuff.c and jdhuff.c, and document that those routines are shared with jclhuff.c and jdlhuff.c as well as with jcphuff.c and jdphuff.c. - Move MAX_DIFF_BITS from jchuff.h into jclhuff.c, the only place where it is used. - Move the predictor and scaler code into jclossls.c and jdlossls.c. - Streamline register usage in the [un]differencers (inspired by similar optimizations in the color [de]converters.) - Restructure the logic in a few places to reduce duplicated code. - Ensure that all lossless-specific code is guarded by C_LOSSLESS_SUPPORTED or D_LOSSLESS_SUPPORTED and that the library can be built successfully if either or both of those macros is undefined. - Remove all short forms of external names introduced by the lossless JPEG patch. (These will not be needed by libjpeg-turbo, so there is no use cleaning them up.) - Various wordsmithing, formatting, and punctuation tweaks - Eliminate various compiler warnings.
DRC 97772cba 2022-11-14T15:36:25 Merge branch 'ijg.lossless' into dev Refer to #402
DRC 217d1a75 2022-11-08T15:01:18 Clean up the lossless JPEG feature - Rename jpeg_simple_lossless() to jpeg_enable_lossless() and modify the function so that it stores the lossless parameters directly in the Ss and Al fields of jpeg_compress_struct rather than using a scan script. - Move the cjpeg -lossless switch into "Switches for advanced users". - Document the libjpeg API and run-time features that are unavailable in lossless mode, and ensure that all parameters, functions, and switches related to unavailable features are ignored or generate errors in lossless mode. - Defer any action that depends on whether lossless mode is enabled until jpeg_start_compress()/jpeg_start_decompress() is called. - Document the purpose of the point transform value. - "Codec" stands for coder/decoder, so it is a bit awkward to say "lossless compression codec" and "lossless decompression codec". Use "lossless compressor" and "lossless decompressor" instead. - Restore backward API/ABI compatibility with libjpeg v6b: * Move the new 'lossless' field from the exposed jpeg_compress_struct and jpeg_decompress_struct structures into the opaque jpeg_comp_master and jpeg_decomp_master structures, and allocate the master structures in the body of jpeg_create_compress() and jpeg_create_decompress(). * Remove the new 'process' field from jpeg_compress_struct and jpeg_decompress_struct and replace it with the old 'progressive_mode' field and the new 'lossless' field. * Remove the new 'data_unit' field from jpeg_compress_struct and jpeg_decompress_struct and replace it with a locally-computed data unit variable. * Restore the names of macros and fields that refer to DCT blocks, and document that they have a different meaning in lossless mode. (Most of them aren't very meaningful in lossless mode anyhow.) * Remove the new alloc_darray() method from jpeg_memory_mgr and replace it with an internal macro that wraps the alloc_sarray() method. * Move the JDIFF* data types from jpeglib.h and jmorecfg.h into jpegint.h. * Remove the new 'codec' field from jpeg_compress_struct and jpeg_decompress_struct and instead reuse the existing internal coefficient control, forward/inverse DCT, and entropy encoding/decoding structures for lossless compression/decompression. * Repurpose existing error codes rather than introducing new ones. (The new JERR_BAD_RESTART and JWRN_MUST_DOWNSCALE codes remain, although JWRN_MUST_DOWNSCALE will probably be removed in libjpeg-turbo, since we have a different way of handling multiple data precisions.) - Automatically enable lossless mode when a scan script with parameters that are only valid for lossless mode is detected, and document the use of scan scripts to generate lossless JPEG images. - Move the sequential and shared Huffman routines back into jchuff.c and jdhuff.c, and document that those routines are shared with jclhuff.c and jdlhuff.c as well as with jcphuff.c and jdphuff.c. - Move MAX_DIFF_BITS from jchuff.h into jclhuff.c, the only place where it is used. - Move the predictor and scaler code into jclossls.c and jdlossls.c. - Streamline register usage in the [un]differencers (inspired by similar optimizations in the color [de]converters.) - Restructure the logic in a few places to reduce duplicated code. - Ensure that all lossless-specific code is guarded by C_LOSSLESS_SUPPORTED or D_LOSSLESS_SUPPORTED and that the library can be built successfully if either or both of those macros is undefined. - Remove all short forms of external names introduced by the lossless JPEG patch. (These will not be needed by libjpeg-turbo, so there is no use cleaning them up.) - Various wordsmithing, formatting, and punctuation tweaks - Eliminate various compiler warnings.
DRC e8b40f3c 2022-11-01T21:45:39 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.
DRC ec6e451d 2022-10-21T16:45:25 Lossless JPEG support: Add copyright attributions Referring to https://github.com/libjpeg-turbo/libjpeg-turbo/issues/402#issuecomment-768348440 and https://github.com/libjpeg-turbo/libjpeg-turbo/issues/402#issuecomment-770221584 Ken Murchison clarified that it was his intent to release the lossless JPEG patch under the IJG License and that adding his name to the copyright headers would be sufficient to acknowledge that any derivatives are based on his work.
Ken Murchison 2e8360e0 1999-04-27T00:00:00 IJG's JPEG software v6b with lossless JPEG support Patch obtained from: https://sourceforge.net/projects/jpeg/files/ftp.oceana.com Author date taken from original announcement and timestamp of patch tarball: https://groups.google.com/g/comp.protocols.dicom/c/rrkP8BxoMRk/m/Ij4dfprggp8J
DRC 7fec5074 2022-03-08T12:34:11 Support 8-bit & 12-bit JPEGs using the same build Partially implements #199 This commit also implements a request from #178 (the ability to compile the libjpeg example as a standalone program.)
y-guyon e6e952d5 2021-07-15T17:33:24 Suppress UBSan error in decode_mcu_fast() This is the same error that d147be83e9a9f904918ba7f834b0fb28e09de9b5 suppressed in decode_mcu_slow(). The image that reproduces this error in decode_mcu_fast() has been added to the libjpeg-turbo seed corpora. Closes #537
DRC d147be83 2021-04-15T23:31:51 Huff decs: Fix/suppress more innocuous UBSan errs - UBSan complained that entropy->restarts_to_go was underflowing an unsigned integer when it was decremented while cinfo->restart_interval == 0. That was, of course, completely innocuous behavior, since the result of the underflowing computation was never used. - d3a3a73f64041c6a6905faf6f9f9832e735fd880 and 7bc9fca4309563d66b0c5665a616285d0e9baeb4 silenced a UBSan signed integer overflow error, but unfortunately other malformed JPEG images have been discovered that cause unsigned integer overflow in the same computation. Since, to the best of our understanding, this behavior is innocuous, this commit reverts the commits listed above, suppresses the UBSan errors, and adds code comments to document the issue.
Guido Vollbeding 9fc018fd 2020-01-12T00:00:00 The Independent JPEG Group's JPEG software v9d
Guido Vollbeding 96e4e7eb 2018-01-14T00:00:00 The Independent JPEG Group's JPEG software v9c
DRC 52fef349 2019-12-10T19:10:55 Eliminate internal use of GETJOCTET() macro Because of 01e30323546d37792e4f682d78d58bb8b3e185ab (officially eliminating support for compilers without unsigned char, since we never effectively supported those compilers anyhow), GETJOCTET() is now a no-op. Since that macro is in jmorecfg.h, it is part of the de facto libjpeg API and must remain in the public headers. However, there is no reason to continue using it internally, and eliminating its internal use improves code readability.
DRC adf9cc94 2019-10-16T20:11:59 j*huff.c: Remove crufty ASSIGN_STATE() macro This macro is a relic of libjpeg's historic need to support a wide variety of C compilers with varying degrees of compatibility. Such was necessary during the open systems era, because C compilers were often supplied by the system vendor. Prior to 1989, there was no C standard per se, and even after ANSI C became a thing, there were still compilers in use that didn't conform to it (libjpeg was first released in 1991.) Realistically, only a handful of C compilers are in widespread use these days, and all modern C compilers should support structure assignment.
DRC 8a0e35b2 2019-04-15T13:41:45 Merge branch 'master' into dev
DRC 7bc9fca4 2019-04-12T09:07:35 jdhuff.c: Silence UBSan signed int overflow err #2 Same as d3a3a73f64041c6a6905faf6f9f9832e735fd880 but in the fast decode path. It was necessary to use a different-sized test image in order to trigger the error in this location. Refer to #347
DRC d3a3a73f 2019-04-10T14:28:47 jdhuff.c: Silence UBSan signed int overflow error Some pathological test images have been created that can cause s to overflow or underflow the signed int data type during decompression. This is technically undefined behavior according to the C spec, although every modern implementation I'm aware of will treat the signed int as a 2's complement unsigned int, thus causing the value to wrap around to INT_MIN if it exceeds INT_MAX. This commit simply makes that behavior explicit in order to shut up UBSan. At least when building for x86-64 or i386 using Clang or GCC, this commit does not change the compiler-generated assembly code at all. The code that triggered this error has existed in the libjpeg code base for at least 20 years (and probably much longer), so the fact that it hasn't produced a user-visible problem in all of that time strongly suggests that UBSan is being overly pedantic here. But if someone can cough up a platform that doesn't wrap around to INT_MIN when 1 is added to INT_MAX, then I'll happily change my opinion. Fixes #347
DRC 133e4af0 2018-09-04T16:56:22 Add x32 ABI support on Linux The x32 ABI is similar to the x86-64 ABI but uses 32-bit pointers. (Refer to https://sites.google.com/site/x32abi) Based on: https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/8da8fc5213d87336d6c7200aaeeca925603e12cf https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/1e33dfea8042230e266b453f53d69a6e37b7f0de https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/24ffea78da0f18d0d467d16e02dfb903e6c0181e https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/dedcf76753c8913ef5c3c6e4ea329d29494b6065 https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/d04228a7b58b9aed5bcbec383630ec1a14a3c9ca https://github.com/libjpeg-turbo/libjpeg-turbo/pull/274/commits/b4ad38316ae1899c8a00b6568bb0325d82edcd7a Closes #274
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 a1dd3568 2016-09-08T21:29:58 Silence additional UBSan warnings NOTE: The jdhuff.c/jdphuff.c warnings should have already been silenced by 8e9cef2e6f5156c4b055a04a8f979b7291fc6b7a, but apparently I need to be REALLY clear that I'm trying to do pointer arithmetic rather than dereference an array. Grrr... Refer to: https://bugzilla.mozilla.org/show_bug.cgi?id=1301250 https://bugzilla.mozilla.org/show_bug.cgi?id=1301256
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
Guido Vollbeding e7f88aec 2013-01-13T00:00:00 The Independent JPEG Group's JPEG software v9
DRC 55a18d40 2016-02-04T18:52:23 Merge branch '1.4.x'
DRC 2d56acb8 2016-02-04T18:47:07 Merge branch '1.3.x' into 1.4.x
DRC c454c595 2016-02-04T18:46:13 Merge branch '1.2.x' into 1.3.x
DRC 0463f7c9 2016-02-04T18:34:38 Prevent overread when decoding malformed JPEG The accelerated Huffman decoder was previously invoked if there were > 128 bytes in the input buffer. However, it is possible to construct a JPEG image with Huffman blocks > 430 bytes in length (http://stackoverflow.com/questions/2734678/jpeg-calculating-max-size). While such images are pathological and could never be created by a JPEG compressor, it is conceivable that an attacker could use such an artifially-constructed image to trigger an input buffer overrun in the libjpeg-turbo decompressor and thus gain access to some of the data on the calling program's heap. This patch simply increases the minimum buffer size for the accelerated Huffman decoder to 512 bytes, which should (hopefully) accommodate any possible input. This addresses a major issue (LJT-01-005) identified in a security audit by Cure53.
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.
DRC 60efb896 2015-09-21T13:13:44 Merge branch '1.4.x'
DRC 8e9cef2e 2015-09-21T12:57:41 Fix various issues reported by the UB sanitizers Most of these involved left shifting a negative number, which is technically undefined (although every modern compiler I'm aware of will implement this by treating the signed integer as a 2's complement unsigned integer-- the LEFT_SHIFT() macro just makes this behavior explicit in order to shut up ubsan.) This also fixes a couple of non-issues in the entropy codecs, whereby the sanitizer reported an out-of-bounds index in the 4th argument of jpeg_make_d_derived_tbl(). In those cases, the index was actually out of bounds (caused by a malformed JPEG image), but jpeg_make_d_derived_tbl() would have caught the error and aborted prior to actually using the invalid address. Here again, the fix was to make our intentions explicit so as to shut up ubsan.
DRC 944aa8e3 2015-07-21T16:43:39 Fix rare bug: right shift by a negative # of bits Under very rare circumstances, decompressing specific corrupt JPEG images would create a situation whereby GET_BITS(1) was invoked from within HUFF_DECODE_FAST() when bits_left=0. This produced a right shift by a negative number of bits, which is undefined in C.
DRC 2a0b4ac3 2015-07-21T16:43:39 Fix rare bug: right shift by a negative # of bits Under very rare circumstances, decompressing specific corrupt JPEG images would create a situation whereby GET_BITS(1) was invoked from within HUFF_DECODE_FAST() when bits_left=0. This produced a right shift by a negative number of bits, which is undefined in C.
DRC cf0e58de 2015-07-21T16:43:39 Fix rare bug: right shift by a negative # of bits Under very rare circumstances, decompressing specific corrupt JPEG images would create a situation whereby GET_BITS(1) was invoked from within HUFF_DECODE_FAST() when bits_left=0. This produced a right shift by a negative number of bits, which is undefined in C.
MIYASAKA Masaru a2e6a9dd 2006-02-04T00:00:00 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
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 a8b67c4f 1995-03-15T00:00:00 The Independent JPEG Group's JPEG software v5b
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 74b9f609 2015-07-21T16:43:39 Fix rare bug: right shift by a negative # of bits Under very rare circumstances, decompressing specific corrupt JPEG images would create a situation whereby GET_BITS(1) was invoked from within HUFF_DECODE_FAST() when bits_left=0. This produced a right shift by a negative number of bits, which is undefined in C.
DRC eb32cc1e 2015-06-25T03:44:36 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
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 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 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 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 a113506d 2014-01-31T17:22:15 Some motion JPEG implementations generate "abbreviated JPEG streams" (JPEG images without the default tables included) for some or all of the video frames, in order to save space. When these are encountered, it is generally expected that they will be decompressed using the default Huffman tables, so libjpeg-turbo now does this unless the tables have been explicitly specified by an application. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1104 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 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 be6d4246 2012-02-07T23:41:10 Compiler warning git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.1.x@785 632fc199-4ca6-4c93-a231-07263d6284db
DRC efe28cec 2012-01-17T11:48:38 Compiler warnings git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@734 632fc199-4ca6-4c93-a231-07263d6284db
DRC bc51580f 2011-04-18T06:52:07 Re-factor and re-license under the libjpeg BSD-style license. Justification: the accelerated Huffman decoding optimizations in libjpeg-turbo were all developed by me as an independent developer. The structure of the inline Huffman decoding 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@590 632fc199-4ca6-4c93-a231-07263d6284db
DRC 9e6378c4 2011-04-16T18:54:12 The previous attempt to handle unexpected markers in the data stream caused breakage in applications that attempted to set bytes_in_buffer to a larger value than the actual size of the JPEG image. The latter behavior was causing the fast decoder to be used for the last MCU in the image under certain circumstances, and this sometimes caused the EOI marker to be encountered by the fast decoder, which was treating it as an "unexpected" marker and throwing an error. Now, the fast decoder simply hands off the decoding of the block to the slow decoder if any marker is encountered. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.0.x@585 632fc199-4ca6-4c93-a231-07263d6284db
DRC 051d9623 2011-04-16T18:53:26 The previous attempt to handle unexpected markers in the data stream caused breakage in applications that attempted to set bytes_in_buffer to a larger value than the actual size of the JPEG image. The latter behavior was causing the fast decoder to be used for the last MCU in the image under certain circumstances, and this sometimes caused the EOI marker to be encountered by the fast decoder, which was treating it as an "unexpected" marker and throwing an error. Now, the fast decoder simply hands off the decoding of the block to the slow decoder if any marker is encountered. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@584 632fc199-4ca6-4c93-a231-07263d6284db
DRC 62de1228 2011-04-16T18:50:42 This is subtle, but an unread marker is not an error unless we run out of bits, which may not occur in the same MCU in which the unread marker is encountered. Thus, don't try to use the fast decoder as long as there is an outstanding unread marker. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.1.x@583 632fc199-4ca6-4c93-a231-07263d6284db
DRC 5c36465f 2011-04-16T17:39:58 The previous attempt to handle unexpected markers in the data stream caused breakage in applications that attempted to set bytes_in_buffer to a larger value than the actual size of the JPEG image. The latter behavior was causing the fast decoder to be used for the last MCU in the image under certain circumstances, and this sometimes caused the EOI marker to be encountered by the fast decoder, which was treating it as an "unexpected" marker and throwing an error. Now, the fast decoder simply hands off the decoding of the block to the slow decoder if any marker is encountered. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.1.x@582 632fc199-4ca6-4c93-a231-07263d6284db
DRC fe6a2ee5 2011-03-18T05:49:26 Throw a warning if an unexpected marker is found in the middle of the JPEG data stream git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.0.x@524 632fc199-4ca6-4c93-a231-07263d6284db
DRC df1c38df 2011-03-18T05:40:33 Throw a warning if an unexpected marker is found in the middle of the JPEG data stream git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.1.x@521 632fc199-4ca6-4c93-a231-07263d6284db
DRC fa1d1838 2011-01-26T05:35:20 Further protect against invalid Huffman codes git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/branches/1.0.x@324 632fc199-4ca6-4c93-a231-07263d6284db
DRC 49aedf42 2011-01-04T08:09:41 Further protect against invalid Huffman codes git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@314 632fc199-4ca6-4c93-a231-07263d6284db
DRC 49967cdb 2010-10-09T19:57:51 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
DRC 36a6eec9 2010-10-08T08:05:44 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
DRC 0fbb28ec 2010-07-30T17:15:52 Handle erroneous Huffman codes git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@221 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 97f8ec4b 2010-03-20T22:38:53 I'm not sure why, but this was necessary in order to return the 32-bit performance to the 0.0.90 baseline git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@165 632fc199-4ca6-4c93-a231-07263d6284db
DRC e885a8bf 2010-03-15T11:34:58 Fix data corruption issues when decompressing large JPEG images and/or using buffered I/O. Specifically, decode_mcu_fast() can potentially process more than 1 MCU, so make sure there is enough space in the buffer to accommodate this case. Otherwise, the buffer pointer goes negative, and bad mojo ensues. Also, the fast decoder's method of handling unread markers doesn't make libjpeg's restart handler happy, so disable fast decode when restarts are used. git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@162 632fc199-4ca6-4c93-a231-07263d6284db
DRC e2816648 2009-09-28T00:33:02 Greatly improve performance of Huffman decoding git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@64 632fc199-4ca6-4c93-a231-07263d6284db