- Wordsmithing, formatting, and grammar tweaks
- Various clarifications and corrections, including specifying whether
a particular buffer or image is used as a source or destination
- Accommodate/mention features that were introduced since the API
documentation was created.
- For clarity, use "packed-pixel" to describe uncompressed
source/destination images that are not planar YUV.
- Use "row" rather than "line" to refer to a single horizontal group of
pixels or component values, for consistency with the libjpeg API
documentation. (libjpeg also uses "scanline", which is a more archaic
term.)
- Use "alignment" rather than "padding" to refer to the number of bytes
by which a row's width is evenly divisible. This consistifies the
documention of the YUV functions and tjLoadImage(). ("Padding"
typically refers to the number of bytes added to each row, which is
not the same thing.)
- Remove all references to "the underlying codec." Although the
TurboJPEG API originated as a cross-platform wrapper for the Intel
Integrated Performance Primitives, Sun mediaLib, QuickTime, and
libjpeg, none of those TurboJPEG implementations has been maintained
since 2009. Nothing would prevent someone from implementing the
TurboJPEG API without libjpeg-turbo, but such an implementation would
not necessarily have an "underlying codec." (It could be fully
self-contained.)
- Use "destination image" rather than "output image", for consistency,
or describe the type of image that will be output.
- Avoid the term "image buffer" and instead use "byte buffer" to
refer to buffers that will hold JPEG images, or describe the type of
image that will be contained in the buffer. (The Java documentation
doesn't use "byte buffer", because the buffer arrays literally have
"byte" in front of them, and since Java doesn't have pointers, it is
not possible for mere mortals to store any other type of data in those
arrays.)
- C: Use "unified" to describe YUV images stored in a single buffer, for
consistency with the Java documentation.
- Use "planar YUV" rather than "YUV planar". Is is our convention to
describe images using {component layout} {colorspace/pixel format}
{image function}, e.g. "packed-pixel RGB source image" or "planar YUV
destination image."
- C: Document the TurboJPEG API version in which a particular function
or macro was introduced, and reorder the backward compatibility
function stubs in turbojpeg.h alphabetically by API version.
- C: Use Markdown rather than HTML tags, where possible, in the Doxygen
comments.
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.
... and modify tjbench.c to match the variable name changes made to
TJBench.java
("checkstyle" = http://checkstyle.sourceforge.net, not our regex-based
checkstyle script)
Also, set the red/green/blue offsets for TJPF_GRAY to -1 rather than 0.
It was undefined behavior for an application to use those arrays/methods
with TJPF_GRAY anyhow, and this makes it easier for applications to
programmatically detect whether a given pixel format has red, green, and
blue components.
Previously, -stoponwarning only had an effect on the underlying
TurboJPEG C functions, but TJBench still aborted if a non-fatal error
occurred. This commit modifies the C version of TJBench such that it
always recovers from a non-fatal error unless -stoponwarning is
specified. Furthermore, the benchmark stores the details of the last
non-fatal error and does not print any subsequent non-fatal error
messages unless they differ from the last one.
Due to limitations in the Java API (specifically, the fact that it
cannot communicate errors, fatal or otherwise, to the calling program
without throwing a TJException), it was only possible to make
decompression operations fully recoverable within TJBench. With other
operations, -stoponwarning still has an effect on the underlying C
library but has no effect at the Java level.
The Java API documentation has been amended to reflect that only certain
methods are truly recoverable, regardless of the state of
TJ.FLAG_STOPONWARNING.
Allow progressive entropy coding to be enabled on a
transform-by-transform basis, and implement a new transform option for
disabling the copying of markers.
Closes#153
- Provide a new C API function and TJException method that allows
calling programs to query the severity of a compression/decompression/
transform error.
- Provide a new flag that instructs the library to immediately stop
compressing/decompressing/transforming if a warning is encountered.
Fixes#151
Use a new checked exception type (TJException) when passing through
errors from the underlying C library. This gives the application a
choice of catching all exceptions or just those from TurboJPEG.
Throw IllegalArgumentException at the JNI level when arguments to the
JNI function are incorrect, and when one of the TurboJPEG "utility"
functions returns an error (because, per the C API specification, those
functions will only return an error if one of their arguments is out of
range.)
Remove "throws Exception" from the signature of any methods that no
longer pass through an error from the TurboJPEG C library.
Credit Viktor for the new code
Code formatting tweaks
Change the behavior of the bailif0() macro in the JNI wrapper so that it doesn't throw an exception for an unexpected NULL condition. In fact, in all cases, the underlying JNI API function (such as GetFieldID(), etc.) will throw an Error on its own whenever it returns NULL, so our custom exceptions were never being thrown in that case anyhow. All we need to do is just detect the error and bail out of the C code.
This also corrects a couple of formatting issues (semicolons aren't needed at the end of class definitions, and @Override should be specified for the methods we're overriding from super-classes, so the compiler can sanity-check that we're actually overriding a method and not declaring a new one.)
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1595 632fc199-4ca6-4c93-a231-07263d6284db
