This gives the user a hint as to whether converting the input file into
a JPEG file with a particular data precision will result in a loss of
precision. Also modify usage.txt and the cjpeg man page to warn the
user about that possibility.
The 8-bit-per-sample image I/O modules have always been built with BMP,
GIF, PBMPLUS, and Targa support, and the 12-bit-per-sample image I/O
modules have always been built with only GIF and PBMPLUS support. In
libjpeg-turbo 2.1.x and prior, cjpeg and djpeg were built with the same
image format support as the image I/O modules. However, because of the
multi-precision feature introduced in libjpeg-turbo 3.0.x, cjpeg and
djpeg are now always built with support for all image formats. Thus,
the error message table compiled into cjpeg and djpeg was a superset of
the error message table compiled into the 12-bit-per-sample and
16-bit-per-sample image I/O modules. If, for example, the
12-bit-per-sample PPM writer threw JERR_PPM_COLORSPACE (== 15, because
it was built with only GIF and PBMPLUS support), then djpeg interpreted
that as JERR_GIF_COLORSPACE (== 15, because it was built with support
for all image formats.) There was no chance of a buffer overrun, since
the error message table lookup was performed against the table compiled
into cjpeg and djpeg, which contained all possible entries. However,
this issue caused an incorrect error message to be displayed by cjpeg or
djpeg if a 12-bit-per-sample or 16-bit-per-sample image I/O module threw
an error. This commit simply removes the *_SUPPORTED #ifdefs from
cderror.h so that all image I/O error messages are always included in
every instance of the image I/O error message table.
Note that a similar issue could have also occurred with the
12-bit-per-sample and 16-bit-per-sample TurboJPEG image I/O functions,
since the 12-bit-per-sample and 16-bit-per-sample image I/O modules
supporting those functions are built with only PBMPLUS support whereas
the library as a whole is built with BMP and PBMPLUS support.
- Restore GIF read/compressed GIF write support from jpeg-6a and
jpeg-9d.
- Integrate jpegtran -wipe and -drop options from jpeg-9a and jpeg-9d.
- Integrate jpegtran -crop extension (for expanding the image size) from
jpeg-9a and jpeg-9d.
- Integrate other minor code tweaks from jpeg-9*
libjpeg-turbo never included that code, because it requires an external
library (the Utah Raster Toolkit.) The RLE image format was supplanted
by GIF in the late 1980s, so it is rarely seen these days. (It had a
lousy Weissman score, anyhow.)
... in which one or more of the color indices is out of range for the
number of palette entries.
Fix partly borrowed from jpeg-9c. This commit also adopts Guido's
JERR_PPM_OUTOFRANGE enum value in lieu of our project-specific
JERR_PPM_TOOLARGE enum value.
Fixes#258
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.
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.
