kmx git

Commit	Date	Message
6b506ed3	2023-06-01T13:11:14	tjexample.c: Prevent integer overflow Because width, height, and tjPixelSize[] are signed integers, signed integer overflow will occur if width * height * tjPixelSize[pixelFormat] > INT_MAX, which would cause an incorrect value to be passed to tj3Alloc(). This commit modifies tjexample.c in the following ways: - Implicitly promote width, height, and tjPixelSize[pixelFormat] to size_t before multiplying them. - Use malloc() rather than tj3Alloc() to allocate the uncompressed image buffer. (tj3Alloc() is only necessary for JPEG buffers that will potentially be reallocated by the TurboJPEG API library.) - If size_t is 32-bit, throw an error if width * height * tjPixelSize[pixelFormat] would overflow the data type. Since tjexample is not installed or packaged, the worst case for this issue was that a downstream application might interpret tjexample.c literally and introduce a similar overflow issue into its own code. However, it's worth noting that such issues could also be introduced when using malloc().
fc881ebb	2023-03-09T20:55:43	TurboJPEG: Implement 4:4:1 chrominance subsampling This allows losslessly transposed or rotated 4:1:1 JPEG images to be losslessly cropped, partially decompressed, or decompressed to planar YUV images. Because tj3Transform() allows multiple lossless transformations to be chained together, all subsampling options need to have a corresponding transposed subsampling option. (This is why 4:4:0 was originally implemented as well.) Otherwise, the documentation would be technically incorrect. It says that images with unknown subsampling types cannot be losslessly cropped, partially decompressed, or decompressed to planar YUV images, but it doesn't say anything about images with known subsampling types whose subsampling type becomes unknown if the image is rotated or transposed. This is one of those situations in which it is easier to implement a feature that works around the problem than to document the problem. Closes #659
fc01f467	2023-01-05T06:36:46	TurboJPEG 3 API overhaul (ChangeLog update forthcoming) - Prefix all function names with "tj3" and remove version suffixes from function names. (Future API overhauls will increment the prefix to "tj4", etc., thus retaining backward API/ABI compatibility without versioning each individual function.) - Replace stateless boolean flags (including TJFLAG_ARITHMETIC and TJFLAG_LOSSLESS, which were never released) with stateful integer parameters, the value of which persists between function calls. * Use parameters for the JPEG quality and subsampling as well, in order to eliminate the awkwardness of specifying function arguments that weren't relevant for lossless compression. * tj3DecompressHeader() now stores all relevant information about the JPEG image, including the width, height, subsampling type, entropy coding type, etc. in parameters rather than returning that information in its arguments. * TJFLAG_LIMITSCANS has been reimplemented as an integer parameter (TJPARAM_SCANLIMIT) that allows the number of scans to be specified. - Use the const keyword for all pointer arguments to unmodified buffers, as well as for both dimensions of 2D pointers. Addresses #395. - Use size_t rather than unsigned long to represent buffer sizes, since unsigned long is a 32-bit type on Windows. Addresses #24. - Return 0 from all buffer size functions if an error occurs, rather than awkwardly trying to return -1 in an unsigned data type. - Implement 12-bit and 16-bit data precision using dedicated compression, decompression, and image I/O functions/methods. * Suffix the names of all data-precision-specific functions with 8, 12, or 16. * Because the YUV functions are intended to be used for video, they are currently only implemented with 8-bit data precision, but they can be expanded to 12-bit data precision in the future, if necessary. * Extend TJUnitTest and TJBench to test 12-bit and 16-bit data precision, using a new -precision option. * Add appropriate regression tests for all of the above to the 'test' target. * Extend tjbenchtest to test 12-bit and 16-bit data precision, and add separate 'tjtest12' and 'tjtest16' targets. * BufferedImage I/O in the Java API is currently limited to 8-bit data precision, since the BufferedImage class does not straightforwardly support higher data precisions. * Extend the PPM reader to convert 12-bit and 16-bit PBMPLUS files to grayscale or CMYK pixels, as it already does for 8-bit files. - Properly accommodate lossless JPEG using dedicated parameters (TJPARAM_LOSSLESS, TJPARAM_LOSSLESSPSV, and TJPARAM_LOSSLESSPT), rather than using a flag and awkwardly repurposing the JPEG quality. Update TJBench to properly reflect whether a JPEG image is lossless. - Re-organize the TJBench usage screen. - Update the Java docs using Java 11, to improve the formatting and eliminate HTML frames. - Use the accurate integer DCT algorithm by default for both compression and decompression, since the "fast" algorithm is a legacy feature, it does not pass the ISO compliance tests, and it is not actually faster on modern x86 CPUs. Remove the -accuratedct option from TJBench and TJExample. - Re-implement the 'tjtest' target using a CMake script that enables the appropriate tests, depending on the data precision and whether or not the Java API is part of the build. - Consolidate the C and Java versions of tjbenchtest into one script. - Consolidate the C and Java versions of tjexampletest into one script. - Combine all initialization functions into a single function (tj3Init()) that accepts an integer parameter specifying the subsystems to initialize. - Enable decompression scaling explicitly, using a new function/method (tj3SetScalingFactor()/TJDecompressor.setScalingFactor()), rather than implicitly using awkward "desired width"/"desired height" parameters. - Introduce a new macro/constant (TJUNSCALED/TJ.UNSCALED) that maps to a scaling factor of 1/1. - Implement partial image decompression, using a new function/method (tj3SetCroppingRegion()/TJDecompressor.setCroppingRegion()) and TJBench option (-crop). Extend tjbenchtest to test the new feature. Addresses #1. - Allow the JPEG colorspace to be specified explicitly when compressing, using a new parameter (TJPARAM_COLORSPACE). This allows JPEG images with the RGB and CMYK colorspaces to be created. - Remove the error/difference image feature from TJBench. Identical images to the ones that TJBench created can be generated using ImageMagick with 'magick composite <original_image> <output_image> -compose difference <diff_image>' - Handle JPEG images with unknown subsampling types. TJPARAM_SUBSAMP is set to TJSAMP_UNKNOWN (== -1) for such images, but they can still be decompressed fully into packed-pixel images or losslessly transformed (with the exception of lossless cropping.) They cannot be partially decompressed or decompressed into planar YUV images. Note also that TJBench, due to its lack of support for imperfect transforms, requires that the subsampling type be known when rotating, flipping, or transversely transposing an image. Addresses #436 - The Java version of TJBench now has identical functionality to the C version. This was accomplished by (somewhat hackishly) calling the TurboJPEG C image I/O functions through JNI and copying the pixels between the C heap and the Java heap. - Add parameters (TJPARAM_RESTARTROWS and TJPARAM_RESTARTBLOCKS) and a TJBench option (-restart) to allow the restart marker interval to be specified when compressing. Eliminate the undocumented TJ_RESTART environment variable. - Add a parameter (TJPARAM_OPTIMIZE), a transform option (TJOPT_OPTIMIZE), and a TJBench option (-optimize) to allow optimized baseline Huffman coding to be specified when compressing. Eliminate the undocumented TJ_OPTIMIZE environment variable. - Add parameters (TJPARAM_XDENSITY, TJPARAM_DENSITY, and TJDENSITYUNITS) to allow the pixel density to be specified when compressing or saving a Windows BMP image and to be queried when decompressing or loading a Windows BMP image. Addresses #77. - Refactor the fuzz targets to use the new API. * Extend decompression coverage to 12-bit and 16-bit data precision. * Replace the awkward cjpeg12 and cjpeg16 targets with proper TurboJPEG-based compress12, compress12-lossless, and compress16-lossless targets - Fix innocuous UBSan warnings uncovered by the new fuzzers. - Implement previous versions of the TurboJPEG API by wrapping the new functions (tested by running the 2.1.x versions of TJBench, via tjbenchtest, and TJUnitTest against the new implementation.) * Remove all JNI functions for deprecated Java methods and implement the deprecated methods using pure Java wrappers. It should be understood that backward API compatibility in Java applies only to the Java classes and that one cannot mix and match a JAR file from one version of libjpeg-turbo with a JNI library from another version. - tj3Destroy() now silently accepts a NULL handle. - tj3Alloc() and tj3Free() now return/accept void pointers, as malloc() and free() do. - The image I/O functions now accept a TurboJPEG instance handle, which is used to transmit/receive parameters and to receive error information. Closes #517
52659f4f	2023-01-23T09:55:13	Merge branch 'main' into dev
2aac5458	2023-01-20T16:02:30	TJExample: Remove "underlying codec" references (Oversight from 9a146f0f23b01869e1bf7c478e12b43f83d59c32)
98ff1fd1	2022-11-21T20:57:39	TurboJPEG: Add lossless JPEG detection capability Add a new TurboJPEG C API function (tjDecompressHeader4()) and Java API method (TJDecompressor.getFlags()) that return the bitwise OR of any flags that are relevant to the JPEG image being decompressed (currently TJFLAG_PROGRESSIVE, TJFLAG_ARITHMETIC, TJFLAG_LOSSLESS, and their Java equivalents.) This allows a calling program to determine whether the image being decompressed is a lossless JPEG image, which means that the decompression scaling feature will not be available and that a full-sized destination buffer should be allocated. More specifically, this fixes a buffer overrun in TJBench, TJExample, and the decompress* fuzz targets that occurred when attempting (in vain) to decompress a lossless JPEG image with decompression scaling enabled.
607b668f	2022-02-10T11:33:49	MSVC: Eliminate C4996 warnings in API libs The primary purpose of this is to encourage adoption of libjpeg-turbo in downstream Windows projects that forbid the use of "deprecated" functions. libjpeg-turbo's usage of those functions was not actually unsafe, because: - libjpeg-turbo always checks the return value of fopen() and ensures that a NULL filename can never be passed to it. - libjpeg-turbo always checks the return value of getenv() and never passes a NULL argument to it. - The sprintf() calls in format_message() (jerror.c) could never overflow the destination string buffer or leave it unterminated as long as the buffer was at least JMSG_LENGTH_MAX bytes in length, as instructed. (Regardless, this commit replaces those calls with snprintf() calls.) - libjpeg-turbo never uses sscanf() to read strings or multi-byte character arrays. - Because of b7d6e84d6a9283dc2bc50ef9fcaadc0cdeb25c9f, wrjpgcom explicitly checks the bounds of the source and destination strings before calling strcat() and strcpy(). - libjpeg-turbo always ensures that the destination string is terminated when using strncpy(). (548490fe5e2aa31cb00f6602d5a478b068b99682 made this explicit.) Regarding thread safety: Technically speaking, getenv() is not thread-safe, because the returned pointer may be invalidated if another thread sets the same environment variable between the time that the first thread calls getenv() and the time that that thread uses the return value. In practice, however, this could only occur with libjpeg-turbo if: (1) A multithreaded calling application used the deprecated and undocumented TJFLAG_FORCEMMX/TJFLAG_FORCESSE/TJFLAG_FORCESSE2 flags in the TurboJPEG API or set one of the corresponding environment variables (which are only intended for testing purposes.) Since the TurboJPEG API library only ever passed string constants to putenv(), the only inherent risk (i.e. the only risk introduced by the library and not the calling application) was that the SIMD extensions may have read an incorrect value from one of the aforementioned environment variables. or (2) A multithreaded calling application modified the value of the JPEGMEM environment variable in one thread while another thread was reading the value of that environment variable (in the body of jpeg_create_compress() or jpeg_create_decompress().) Given that the libjpeg API provides a thread-safe way for applications to modify the default memory limit without using the JPEGMEM environment variable, direct modification of that environment variable by calling applications is not supported. Microsoft's implementation of getenv_s() does not claim to be thread-safe either, so this commit uses getenv_s() solely to mollify Visual Studio. New inline functions and macros (GETENV_S() and PUTENV_S) wrap getenv_s()/_putenv_s() when building for Visual Studio and getenv()/setenv() otherwise, but GETENV_S()/PUTENV_S() provide no advantages over getenv()/setenv() other than parameter validation. They are implemented solely for convenience. Technically speaking, strerror() is not thread-safe, because the returned pointer may be invalidated if another thread changes the locale and/or calls strerror() between the time that the first thread calls strerror() and the time that that thread uses the return value. In practice, however, this could only occur with libjpeg-turbo if a multithreaded calling application encountered a file I/O error in tjLoadImage() or tjSaveImage(). Since both of those functions immediately copy the string returned from strerror() into a thread-local buffer, the risk is minimal, and the worst case would involve an incorrect error string being reported to the calling application. Regardless, this commit uses strerror_s() in the TurboJPEG API library when building for Visual Studio. Note that strerror_r() could have been used on Un*x systems, but it would have been necessary to handle both the POSIX and GNU implementations of that function and perform widespread compatibility testing. Such is left as an exercise for another day. Fixes #568
3179f330	2021-01-04T14:54:35	tjexample.c: Fix mem leak if tjTransform() fails Fixes #479
00607ec2	2020-01-08T14:22:35	Eliminate unnecessary NULL checks before tjFree() + document that tjFree() accepts NULL pointers without complaint. Effectively, it has had that behavior all along, but the API does not guarantee that tjFree() will be implemented with free() behind the scenes, so it's best to formalize the behavior.
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)
bce58f48	2019-04-12T07:49:35	Consistify formatting of macros in TurboJPEG code
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.
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.
8c40ac8a	2017-11-16T18:46:01	Add TurboJPEG C example and clean up Java example Also rename example.c --> example.txt and add a disclaimer to that file so people will stop trying to compile it.

6b506ed3

2023-06-01T13:11:14

tjexample.c: Prevent integer overflow Because width, height, and tjPixelSize[] are signed integers, signed integer overflow will occur if width * height * tjPixelSize[pixelFormat] > INT_MAX, which would cause an incorrect value to be passed to tj3Alloc(). This commit modifies tjexample.c in the following ways: - Implicitly promote width, height, and tjPixelSize[pixelFormat] to size_t before multiplying them. - Use malloc() rather than tj3Alloc() to allocate the uncompressed image buffer. (tj3Alloc() is only necessary for JPEG buffers that will potentially be reallocated by the TurboJPEG API library.) - If size_t is 32-bit, throw an error if width * height * tjPixelSize[pixelFormat] would overflow the data type. Since tjexample is not installed or packaged, the worst case for this issue was that a downstream application might interpret tjexample.c literally and introduce a similar overflow issue into its own code. However, it's worth noting that such issues could also be introduced when using malloc().

fc881ebb

2023-03-09T20:55:43

TurboJPEG: Implement 4:4:1 chrominance subsampling This allows losslessly transposed or rotated 4:1:1 JPEG images to be losslessly cropped, partially decompressed, or decompressed to planar YUV images. Because tj3Transform() allows multiple lossless transformations to be chained together, all subsampling options need to have a corresponding transposed subsampling option. (This is why 4:4:0 was originally implemented as well.) Otherwise, the documentation would be technically incorrect. It says that images with unknown subsampling types cannot be losslessly cropped, partially decompressed, or decompressed to planar YUV images, but it doesn't say anything about images with known subsampling types whose subsampling type becomes unknown if the image is rotated or transposed. This is one of those situations in which it is easier to implement a feature that works around the problem than to document the problem. Closes #659

fc01f467

2023-01-05T06:36:46

TurboJPEG 3 API overhaul (ChangeLog update forthcoming) - Prefix all function names with "tj3" and remove version suffixes from function names. (Future API overhauls will increment the prefix to "tj4", etc., thus retaining backward API/ABI compatibility without versioning each individual function.) - Replace stateless boolean flags (including TJ*FLAG_ARITHMETIC and TJ*FLAG_LOSSLESS, which were never released) with stateful integer parameters, the value of which persists between function calls. * Use parameters for the JPEG quality and subsampling as well, in order to eliminate the awkwardness of specifying function arguments that weren't relevant for lossless compression. * tj3DecompressHeader() now stores all relevant information about the JPEG image, including the width, height, subsampling type, entropy coding type, etc. in parameters rather than returning that information in its arguments. * TJ*FLAG_LIMITSCANS has been reimplemented as an integer parameter (TJ*PARAM_SCANLIMIT) that allows the number of scans to be specified. - Use the const keyword for all pointer arguments to unmodified buffers, as well as for both dimensions of 2D pointers. Addresses #395. - Use size_t rather than unsigned long to represent buffer sizes, since unsigned long is a 32-bit type on Windows. Addresses #24. - Return 0 from all buffer size functions if an error occurs, rather than awkwardly trying to return -1 in an unsigned data type. - Implement 12-bit and 16-bit data precision using dedicated compression, decompression, and image I/O functions/methods. * Suffix the names of all data-precision-specific functions with 8, 12, or 16. * Because the YUV functions are intended to be used for video, they are currently only implemented with 8-bit data precision, but they can be expanded to 12-bit data precision in the future, if necessary. * Extend TJUnitTest and TJBench to test 12-bit and 16-bit data precision, using a new -precision option. * Add appropriate regression tests for all of the above to the 'test' target. * Extend tjbenchtest to test 12-bit and 16-bit data precision, and add separate 'tjtest12' and 'tjtest16' targets. * BufferedImage I/O in the Java API is currently limited to 8-bit data precision, since the BufferedImage class does not straightforwardly support higher data precisions. * Extend the PPM reader to convert 12-bit and 16-bit PBMPLUS files to grayscale or CMYK pixels, as it already does for 8-bit files. - Properly accommodate lossless JPEG using dedicated parameters (TJ*PARAM_LOSSLESS, TJ*PARAM_LOSSLESSPSV, and TJ*PARAM_LOSSLESSPT), rather than using a flag and awkwardly repurposing the JPEG quality. Update TJBench to properly reflect whether a JPEG image is lossless. - Re-organize the TJBench usage screen. - Update the Java docs using Java 11, to improve the formatting and eliminate HTML frames. - Use the accurate integer DCT algorithm by default for both compression and decompression, since the "fast" algorithm is a legacy feature, it does not pass the ISO compliance tests, and it is not actually faster on modern x86 CPUs. * Remove the -accuratedct option from TJBench and TJExample. - Re-implement the 'tjtest' target using a CMake script that enables the appropriate tests, depending on the data precision and whether or not the Java API is part of the build. - Consolidate the C and Java versions of tjbenchtest into one script. - Consolidate the C and Java versions of tjexampletest into one script. - Combine all initialization functions into a single function (tj3Init()) that accepts an integer parameter specifying the subsystems to initialize. - Enable decompression scaling explicitly, using a new function/method (tj3SetScalingFactor()/TJDecompressor.setScalingFactor()), rather than implicitly using awkward "desired width"/"desired height" parameters. - Introduce a new macro/constant (TJUNSCALED/TJ.UNSCALED) that maps to a scaling factor of 1/1. - Implement partial image decompression, using a new function/method (tj3SetCroppingRegion()/TJDecompressor.setCroppingRegion()) and TJBench option (-crop). Extend tjbenchtest to test the new feature. Addresses #1. - Allow the JPEG colorspace to be specified explicitly when compressing, using a new parameter (TJ*PARAM_COLORSPACE). This allows JPEG images with the RGB and CMYK colorspaces to be created. - Remove the error/difference image feature from TJBench. Identical images to the ones that TJBench created can be generated using ImageMagick with 'magick composite <original_image> <output_image> -compose difference <diff_image>' - Handle JPEG images with unknown subsampling types. TJ*PARAM_SUBSAMP is set to TJ*SAMP_UNKNOWN (== -1) for such images, but they can still be decompressed fully into packed-pixel images or losslessly transformed (with the exception of lossless cropping.) They cannot be partially decompressed or decompressed into planar YUV images. Note also that TJBench, due to its lack of support for imperfect transforms, requires that the subsampling type be known when rotating, flipping, or transversely transposing an image. Addresses #436 - The Java version of TJBench now has identical functionality to the C version. This was accomplished by (somewhat hackishly) calling the TurboJPEG C image I/O functions through JNI and copying the pixels between the C heap and the Java heap. - Add parameters (TJ*PARAM_RESTARTROWS and TJ*PARAM_RESTARTBLOCKS) and a TJBench option (-restart) to allow the restart marker interval to be specified when compressing. Eliminate the undocumented TJ_RESTART environment variable. - Add a parameter (TJ*PARAM_OPTIMIZE), a transform option (TJ*OPT_OPTIMIZE), and a TJBench option (-optimize) to allow optimized baseline Huffman coding to be specified when compressing. Eliminate the undocumented TJ_OPTIMIZE environment variable. - Add parameters (TJ*PARAM_XDENSITY, TJ*PARAM_DENSITY, and TJ*DENSITYUNITS) to allow the pixel density to be specified when compressing or saving a Windows BMP image and to be queried when decompressing or loading a Windows BMP image. Addresses #77. - Refactor the fuzz targets to use the new API. * Extend decompression coverage to 12-bit and 16-bit data precision. * Replace the awkward cjpeg12 and cjpeg16 targets with proper TurboJPEG-based compress12, compress12-lossless, and compress16-lossless targets - Fix innocuous UBSan warnings uncovered by the new fuzzers. - Implement previous versions of the TurboJPEG API by wrapping the new functions (tested by running the 2.1.x versions of TJBench, via tjbenchtest, and TJUnitTest against the new implementation.) * Remove all JNI functions for deprecated Java methods and implement the deprecated methods using pure Java wrappers. It should be understood that backward API compatibility in Java applies only to the Java classes and that one cannot mix and match a JAR file from one version of libjpeg-turbo with a JNI library from another version. - tj3Destroy() now silently accepts a NULL handle. - tj3Alloc() and tj3Free() now return/accept void pointers, as malloc() and free() do. - The image I/O functions now accept a TurboJPEG instance handle, which is used to transmit/receive parameters and to receive error information. Closes #517

52659f4f

2023-01-23T09:55:13

Merge branch 'main' into dev

2aac5458

2023-01-20T16:02:30

TJExample: Remove "underlying codec" references (Oversight from 9a146f0f23b01869e1bf7c478e12b43f83d59c32)

98ff1fd1

2022-11-21T20:57:39

TurboJPEG: Add lossless JPEG detection capability Add a new TurboJPEG C API function (tjDecompressHeader4()) and Java API method (TJDecompressor.getFlags()) that return the bitwise OR of any flags that are relevant to the JPEG image being decompressed (currently TJFLAG_PROGRESSIVE, TJFLAG_ARITHMETIC, TJFLAG_LOSSLESS, and their Java equivalents.) This allows a calling program to determine whether the image being decompressed is a lossless JPEG image, which means that the decompression scaling feature will not be available and that a full-sized destination buffer should be allocated. More specifically, this fixes a buffer overrun in TJBench, TJExample, and the decompress* fuzz targets that occurred when attempting (in vain) to decompress a lossless JPEG image with decompression scaling enabled.

607b668f

2022-02-10T11:33:49

MSVC: Eliminate C4996 warnings in API libs The primary purpose of this is to encourage adoption of libjpeg-turbo in downstream Windows projects that forbid the use of "deprecated" functions. libjpeg-turbo's usage of those functions was not actually unsafe, because: - libjpeg-turbo always checks the return value of fopen() and ensures that a NULL filename can never be passed to it. - libjpeg-turbo always checks the return value of getenv() and never passes a NULL argument to it. - The sprintf() calls in format_message() (jerror.c) could never overflow the destination string buffer or leave it unterminated as long as the buffer was at least JMSG_LENGTH_MAX bytes in length, as instructed. (Regardless, this commit replaces those calls with snprintf() calls.) - libjpeg-turbo never uses sscanf() to read strings or multi-byte character arrays. - Because of b7d6e84d6a9283dc2bc50ef9fcaadc0cdeb25c9f, wrjpgcom explicitly checks the bounds of the source and destination strings before calling strcat() and strcpy(). - libjpeg-turbo always ensures that the destination string is terminated when using strncpy(). (548490fe5e2aa31cb00f6602d5a478b068b99682 made this explicit.) Regarding thread safety: Technically speaking, getenv() is not thread-safe, because the returned pointer may be invalidated if another thread sets the same environment variable between the time that the first thread calls getenv() and the time that that thread uses the return value. In practice, however, this could only occur with libjpeg-turbo if: (1) A multithreaded calling application used the deprecated and undocumented TJFLAG_FORCEMMX/TJFLAG_FORCESSE/TJFLAG_FORCESSE2 flags in the TurboJPEG API or set one of the corresponding environment variables (which are only intended for testing purposes.) Since the TurboJPEG API library only ever passed string constants to putenv(), the only inherent risk (i.e. the only risk introduced by the library and not the calling application) was that the SIMD extensions may have read an incorrect value from one of the aforementioned environment variables. or (2) A multithreaded calling application modified the value of the JPEGMEM environment variable in one thread while another thread was reading the value of that environment variable (in the body of jpeg_create_compress() or jpeg_create_decompress().) Given that the libjpeg API provides a thread-safe way for applications to modify the default memory limit without using the JPEGMEM environment variable, direct modification of that environment variable by calling applications is not supported. Microsoft's implementation of getenv_s() does not claim to be thread-safe either, so this commit uses getenv_s() solely to mollify Visual Studio. New inline functions and macros (GETENV_S() and PUTENV_S) wrap getenv_s()/_putenv_s() when building for Visual Studio and getenv()/setenv() otherwise, but GETENV_S()/PUTENV_S() provide no advantages over getenv()/setenv() other than parameter validation. They are implemented solely for convenience. Technically speaking, strerror() is not thread-safe, because the returned pointer may be invalidated if another thread changes the locale and/or calls strerror() between the time that the first thread calls strerror() and the time that that thread uses the return value. In practice, however, this could only occur with libjpeg-turbo if a multithreaded calling application encountered a file I/O error in tjLoadImage() or tjSaveImage(). Since both of those functions immediately copy the string returned from strerror() into a thread-local buffer, the risk is minimal, and the worst case would involve an incorrect error string being reported to the calling application. Regardless, this commit uses strerror_s() in the TurboJPEG API library when building for Visual Studio. Note that strerror_r() could have been used on Un*x systems, but it would have been necessary to handle both the POSIX and GNU implementations of that function and perform widespread compatibility testing. Such is left as an exercise for another day. Fixes #568

3179f330

2021-01-04T14:54:35

tjexample.c: Fix mem leak if tjTransform() fails Fixes #479

00607ec2

2020-01-08T14:22:35

Eliminate unnecessary NULL checks before tjFree() + document that tjFree() accepts NULL pointers without complaint. Effectively, it has had that behavior all along, but the API does not guarantee that tjFree() will be implemented with free() behind the scenes, so it's best to formalize the behavior.

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)

bce58f48

2019-04-12T07:49:35

Consistify formatting of macros in TurboJPEG code

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.

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.

8c40ac8a

2017-11-16T18:46:01

Add TurboJPEG C example and clean up Java example Also rename example.c --> example.txt and add a disclaimer to that file so people will stop trying to compile it.

kc3-lang/libjpeg-turbo/tjexample.c

tjexample.c

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