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e0dcefd5
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2025-09-25T18:13:10
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Arm/x86: Allow JSIMD_NOHUFFENC to disable prog.
Due to an oversight when the progressive Huffman encoding SIMD modules
were developed, JSIMD_NOHUFFENC was not extended to those modules.
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5e27ca23
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2025-09-19T14:21:49
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x86: Reformat NASM code to improve readability
(and simplify the checkstyle script)
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4e151a4a
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2025-08-26T21:11:07
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Remove vestigial filenames from SIMD code headers
These were a relic of libjpeg/SIMD, which attempted to follow the
conventions of the libjpeg source code, but they are no longer relevant
(or even accurate in some cases.)
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64567381
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2024-08-31T17:31:02
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Merge branch 'main' into dev
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eb753630
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2024-08-31T16:50:08
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Update URLs
- Eliminate unnecessary "www."
- Use HTTPS.
- Update Java, MSYS, tdm-gcc, and NSIS URLs.
- Update URL and title of Agner Fog's assembly language optimization
manual.
- Remove extraneous information about MASM and Borland Turbo Assembler
and outdated NASM URLs from the x86 assembly headers, and mention
Yasm.
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7e45654c
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2024-03-04T18:10:16
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Merge branch 'main' into dev
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13355475
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2024-02-29T12:18:49
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x86 SIMD: Capitalize all instruction-like macros
(to improve code readability)
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e69dd40c
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2024-01-23T13:26:41
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Reorganize source to make things easier to find
- Move all libjpeg documentation, except for README.ijg, into the doc/
subdirectory.
- Move the TurboJPEG C API documentation from doc/html/ into
doc/turbojpeg/.
- Move all C source code and headers into a src/ subdirectory.
- Move turbojpeg-jni.c into the java/ subdirectory.
Referring to #226, there is no ideal solution to this problem. A
semantically ideal solution would have involved placing all source code,
including the SIMD and Java source code, under src/ (or perhaps placing
C library source code under lib/ and C test program source code under
test/), all header files under include/, and all documentation under
doc/. However:
- To me it makes more sense to have separate top-level directories for
each language, since the SIMD extensions and the Java API are
technically optional features. src/ now contains only the code that
is relevant to the core C API libraries and associated programs.
- I didn't want to bury the java/ and simd/ directories or add a level
of depth to them, since both directories already contain source code
that is 3-4 levels deep.
- I would prefer not to separate the header files from the C source
code, because:
1. It would be disruptive. libjpeg and libjpeg-turbo have
historically placed C source code and headers in the same
directory, and people who are familiar with both projects (self
included) are used to looking for the headers in the same directory
as the C source code.
2. In terms of how the headers are used internally in libjpeg-turbo,
the distinction between public and private headers is a bit fuzzy.
- It didn't make sense to separate the test source code from the library
source code, since there is not a clear distinction in some cases.
(For instance, the IJG image I/O functions are used by cjpeg and djpeg
as well as by the TurboJPEG API.)
This solution is minimally disruptive, since it keeps all C source code
and headers together and keeps java/ and simd/ as top-level directories.
It is a bit awkward, because java/ and simd/ technically contain source
code, even though they are not under src/. However, other solutions
would have been more awkward for different reasons.
Closes #226
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fa2b6ea0
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2024-01-12T18:21:41
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Eliminate duplicate copies of jpeg_nbits_table
ef9a4e05ba919494cbebe50e15f332de5ab97e82 (libjpeg-turbo 1.4.x), which
was based on
https://bug815473.bmoattachments.org/attachment.cgi?id=692126
(https://bugzilla.mozilla.org/show_bug.cgi?id=815473), modified the C
baseline Huffman encoder so that it precomputes jpeg_nbits_table, in
order to facilitate sharing the table among multiple processes.
However, libjpeg-turbo never shared the table, and because the table was
implemented as a static array, f3a8684cd1c28e557d394470962a7a224c76ddbc
(libjpeg-turbo 1.5.x) and 37bae1a0e977ee1ba769e6f0aa27e519ab6e58c6
(libjpeg-turbo 2.0.x) each introduced a duplicate copy of the table for
(respectively) the SSE2 baseline Huffman encoder and the C progressive
Huffman encoder.
This commit does the following:
- Move the duplicated code in jchuff.c and jcphuff.c, originally
introduced in 0cfc4c17b740cb2cbb11f9d85c8ab3745d5b913a and
37bae1a0e977ee1ba769e6f0aa27e519ab6e58c6, into a header
(jpeg_nbits.h).
- Credit the co-author of 0cfc4c17b740cb2cbb11f9d85c8ab3745d5b913a.
(Refer to https://sourceforge.net/p/libjpeg-turbo/patches/57).
- Modify the SSE2 baseline Huffman encoder so that the C Huffman
encoders can share its definition of jpeg_nbits_table.
- Move the definition of jpeg_nbits_table into a C source file
(jpeg_nbits.c) rather than a header, and define the table only if
USE_CLZ_INTRINSIC is undefined and the SSE2 baseline Huffman encoder
will not be built.
- Apply hidden symbol visibility to the shared definition of
jpeg_nbits_table, if the compiler supports the necessary attribute.
(In practice, only Visual C++ doesn't.)
Closes #114
See also:
https://bugzilla.mozilla.org/show_bug.cgi?id=1501523
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4e028ecd
|
2023-02-02T08:55:37
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SIMD/x86: Initialize simd_support before every use
As long as a libjpeg instance is only used by one thread at a time, a
program is technically within its rights to call jpeg_start_*compress()
in one thread and jpeg_(read|write)_*(), with the same libjpeg instance,
in a second thread. However, because the various jsimd_can*() functions
are called within the body of jpeg_start_*compress() and simd_support is
now thread-local (due to f579cc11b33e5bfeb9931e37cc74b4a33c95d2e6), that
led to a situation in which simd_support was initialized in the first
thread but not the second. The uninitialized value of simd_support is
0xFFFFFFFF, which the second thread interpreted to mean that it could
use any instruction set, and when it attempted to use AVX2 instructions
on a CPU that didn't support them, an illegal instruction error
occurred.
This issue was known to affect libvips.
This commit modifies the i386 and x86-64 SIMD dispatchers so that the
various jsimd_*() functions always call init_simd(), if simd_support is
uninitialized, prior to dispatching based on the value of simd_support.
Note that the other SIMD dispatchers don't need this, because only the
x86 SIMD extensions currently support multiple instruction sets.
This patch has been verified to be performance-neutral to within
+/- 0.4% with 32-bit and 64-bit code running on a 2.8 GHz Intel Xeon
W3530 and a 3.6 GHz Intel Xeon W2123.
Fixes #649
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78a36f6d
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2022-11-15T17:01:17
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Fix buffer overrun in 12-bit prog Huffman encoder
Regression introduced by 16bd984557fa2c490be0b9665e2ea0d4274528a8 and
5b177b3cab5cfb661256c1e74df160158ec6c34e
The pre-computed absolute values used in encode_mcu_AC_first() and
encode_mcu_AC_refine() were stored in a JCOEF (signed short) array.
When attempting to losslessly transform a specially-crafted malformed
12-bit JPEG image with a coefficient value of -32768 into a progressive
12-bit JPEG image, the progressive Huffman encoder attempted to store
the absolute value of -32768 in the JCOEF array, thus overflowing the
16-bit signed data type. Therefore, at this point in the code:
https://github.com/libjpeg-turbo/libjpeg-turbo/blob/8c5e78ce292c1642057102eac42f12ab57964293/jcphuff.c#L889
the absolute value was read as -32768, which caused the test at
https://github.com/libjpeg-turbo/libjpeg-turbo/blob/8c5e78ce292c1642057102eac42f12ab57964293/jcphuff.c#L896
to fail, falling through to
https://github.com/libjpeg-turbo/libjpeg-turbo/blob/8c5e78ce292c1642057102eac42f12ab57964293/jcphuff.c#L908
with an overly large value of r (46) that, when shifted left four
places, incremented, and passed to emit_symbol(), exceeded the maximum
index (255) for the derived code tables. Fortunately, the buffer
overrun was fully contained within phuff_entropy_encoder, so the issue
did not generate a segfault or other user-visible errant behavior, but
it did cause a UBSan failure that was detected by OSS-Fuzz.
This commit introduces an unsigned JCOEF (UJCOEF) data type and uses it
to store the absolute values of DCT coefficients computed by the
AC_first_prepare() and AC_refine_prepare() methods.
Note that the changes to the Arm Neon progressive Huffman encoder
extensions cause signed 16-bit instructions to be replaced with
equivalent unsigned 16-bit instructions, so the changes should be
performance-neutral.
Based on:
https://github.com/mayeut/libjpeg-turbo/commit/bbf61c0382c4f8bd1f1cfc666467581496c2fb7c
Closes #628
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eb0a024a
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2022-10-04T12:51:38
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Remove redundant jconfigint.h #includes
Because of 607b668ff96e40fdc749de9b1bb98e7f40c86d93, jconfigint.h is
included by jinclude.h.
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f579cc11
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2022-10-03T19:46:09
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Make SIMD capability variables thread-local ...
... on platforms that support TLS, which should include all
currently-supported platforms
(https://libjpeg-turbo.org/Documentation/OfficialBinaries)
Addresses a concern raised in #87
Although it is still my opinion that the data race in init_simd() was
innocuous, we can now fix it for free thanks to
ae87a958613b69628b92088b313ded0d4f59a716, so why not?
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607b668f
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2022-02-10T11:33:49
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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
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e795afc3
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2021-03-25T22:36:15
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SSE2: Fix prog Huff enc err if Sl%32==0 && Al!=0
(regression introduced by 16bd984557fa2c490be0b9665e2ea0d4274528a8)
This implements the same fix for
jsimd_encode_mcu_AC_refine_prepare_sse2() that
a81a8c137b3f1c65082aa61f236aa88af61b3ad4 implemented for
jsimd_encode_mcu_AC_first_prepare_sse2().
Based on:
https://github.com/MegaByte/libjpeg-turbo/commit/1a59587397150c9ef9dffc5813cb3891db4bc0c8
https://github.com/MegaByte/libjpeg-turbo/commit/eb176a91d87a470bf8c987be786668aa944dd1dd
Fixes #509
Closes #510
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7c1a1789
|
2020-11-05T16:04:55
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Merge branch 'master' into dev
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6e632af9
|
2020-11-04T10:13:06
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|
Demote "fast" [I]DCT algorithms to legacy status
- Refer to the "slow" [I]DCT algorithms as "accurate" instead, since
they are not slow under libjpeg-turbo.
- Adjust documentation claims to reflect the fact that the "slow" and
"fast" algorithms produce about the same performance on AVX2-equipped
CPUs (because of the dual-lane nature of AVX2, it was not possible to
accelerate the "fast" algorithm beyond what was achievable with SSE2.)
Also adjust the claims to reflect the fact that the "fast" algorithm
tends to be ~5-15% faster than the "slow" algorithm on
non-AVX2-equipped CPUs, regardless of the use of the libjpeg-turbo
SIMD extensions.
- Indicate the legacy status of the "fast" and float algorithms in the
documentation and cjpeg/djpeg usage info.
- Remove obsolete paragraph in the djpeg man page that suggested that
the float algorithm could be faster than the "fast" algorithm on some
CPUs.
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9c6f79e9
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2019-11-13T14:36:37
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Fix formatting issues detected by checkstyle
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cbf0fcc8
|
2019-11-05T11:56:06
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i386 SSE2 Huffman: Fix pointer arithmetic issue
Splitting the pointer arithmetic in GET_SYM() into a separate add and
sub instruction was an attempt to work around an error ("invalid operand
type") that occurred when assembling the file with NASM. However, this
created a link error on macOS ("ld: illegal text-relocation to
'_jconst_huff_encode_one_block' in
simd/CMakeFiles/simd.dir/i386/jchuff-sse2.asm.o from
'_jsimd_huff_encode_one_block_sse2' in
simd/CMakeFiles/simd.dir/i386/jchuff-sse2.asm.o for architecture i386")
and also changed the alignment of the code in ways that might have
affected the previous benchmark results (which took a great deal of time
to obtain.) Ultimately, the path of least resistance is just to
require NASM 2.13 or later.
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087c29e0
|
2018-10-22T10:05:18
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|
Optimize Huffman encoding
This commit improves the C and SSE2 Huffman encoding implementations in
the following ways:
- Avoid using xmm8-xmm15 in the x86-64 SSE2 implementation. There is no
actual need to use those registers, and avoiding them produces a
cleaner WIN64 function entry/exit-- as well as shorter code, since REX
prefixes can be avoided (this is helpful on certain CPUs, such as
Intel Atom, for which instruction fetch and decoding can be a
bottleneck.)
- Optimize register usage so that fewer REX prefixes and
register-register moves are needed.
- Use the bit counter to store the number of free bits in the bit buffer
rather than the number of bits in the bit buffer. This changes the
method for inserting a code into the bit buffer to:
(put_buffer |= code << (free_bits -= code_size));
As a result:
* Only one bit counter needs to stay in a register (we just keep it in
cl.)
* The bit buffer contents are already properly aligned to be written
out (after a byte swap.)
* Adjusting the free bits counter and checking if the bit buffer is
full can be combined into a single operation.
* We can wait to flush the bit buffer until the buffer is actually
full and not just in danger of becoming full. Thus, eight bytes can
be flushed at a time.
- Speed is quite sensitive to the alignment of branch target labels, so
insert some padding and remove branches from the flush code.
(Flushing this way isn't actually faster when compared to using
branches, but the branchless code doesn't need extra alignment and is
thus smaller.)
- Speculatively write out the bit buffer as a single 8-byte write,
falling back to a byte-by-byte write only if there are any 0xFF bytes
in the bit buffer that need to be encoded as 0xFF 0x00.
- Use MMX registers for the 32-bit implementation (so the bit buffer can
be 64 bits wide.)
- Slightly reduce overall function code size.
- Eliminate or combine a few SSE instructions.
- Make some minor improvements to instruction scheduling.
- Adjust flush_bits() in jchuff.c to handle cases in which the bit
buffer has less than 7 free bits (apparently that couldn't happen
before.)
Based on:
https://github.com/1camper/libjpeg-turbo/commit/947a09defa2ec848322b1bae050d1b57b316a32a
https://github.com/1camper/libjpeg-turbo/commit/262ebb6b816fd8a49ff4d7185f6c5153dddde02f
https://github.com/1camper/libjpeg-turbo/commit/6e9a091221bb244c8ba232a942650e94254ffcf0
See change log for performance claims.
Closes #292
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3a32d199
|
2019-10-17T19:59:01
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x86 SIMD: Consistify capitalization of NASM types
byte, word, dword, qword, oword, and yword are all assembler keywords,
so it makes sense to use lowercase for these so as not to mistake them
for macros or constants.
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9a51a87a
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2019-10-17T11:21:32
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x86 SIMD: Remove obsolete [TAB8] comments
With apologies to Richard Hendricks, our assembly code no longer uses
tabs.
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a81a8c13
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2019-08-14T13:17:11
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SSE2 SIMD: Fix prog Huffman enc. error if Sl%16==0
(regression introduced by 5b177b3cab5cfb661256c1e74df160158ec6c34e)
The SSE2 implementation of progressive Huffman encoding performed
extraneous iterations when the scan length was a multiple of 16.
Based on:
https://github.com/rouault/libjpeg-turbo/commit/bb7f1ef98305da915e581b59bd0ec2ef7bdb8468
Fixes #335
Closes #367
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aa9db616
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2019-04-15T17:55:47
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x86 SIMD: Check for CPUID leaf 07H before using
According to Intel's manual [1], "If a value entered for CPUID.EAX is
higher than the maximum input value for basic or extended function for
that processor then the data for the highest basic information leaf is
returned."
Right now, libjpeg-turbo doesn't first check that leaf 07H is supported
before attempting to use it, so the ostensible AVX2 bit (Bit 05) of the
CPUID result might actually be Bit 05 from a lower leaf. That bit might
be set, even if the CPU doesn't support AVX2.
This commit modifies the x86 and x86-64 SIMD feature detection code so
that it first checks whether CPUID leaf 07H is supported before
attempting to use it to check for AVX2 instruction support.
DRC:
This commit should fix
https://bugzilla.mozilla.org/show_bug.cgi?id=1520760
However, I have not personally been able to reproduce that issue,
despite using a Nehalem (pre-AVX2) CPU on which the maximum CPUID leaf
has been limited via a BIOS setting.
Closes #348
[1]
"Intel® 64 and IA-32 Architectures Software Developer's Manual, Volume 2 (2A, 2B, 2C & 2D): Instruction Set Reference, A-Z", https://software.intel.com/sites/default/files/managed/a4/60/325383-sdm-vol-2abcd.pdf, page 3-192.
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d5f281b7
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2018-09-28T15:46:35
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SIMD: Fix c000001d exception on Win 7 w/o SP1
Apparently Windows 7 without SP1 has O/S support for XSAVE but not for
YMM registers, and this exposed a bug in our usage of xgetbv. The test
instruction will set ZF only if none of the bits match between the two
operarands, so in effect, we were enabling AVX2 instructions if the O/S
supported XSAVE and the CPU supported AVX2 but the O/S only supported
XMM registers. This bug was not exposed on, for instance, Windows XP or
RHEL 5 because those O/S's do not support XSAVE.
Fixes #288
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269e84c9
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2018-04-10T00:02:57
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jsimd_can_encode_mcu_AC_*(): Remove useless checks
These were necessary for the first iteration of the feature (see #46),
which provided a different C front end for the SIMD version of the
function. The final version of the feature uses a common C front end
for both SIMD and non-SIMD implementations, so these checks are no
longer necessary.
Closes #231
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58cb10ee
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2018-03-31T13:51:31
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Eliminate compiler warnings w/ Solaris Studio
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5b177b3c
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2018-03-22T11:36:43
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C/SSE2 optimization of encode_mcu_AC_first()
This commit adds C and SSE2 optimizations for the encode_mcu_AC_first()
function used in progressive Huffman encoding.
The image used for testing can be retrieved from this page:
https://blog.cloudflare.com/doubling-the-speed-of-jpegtran
All timings done on `Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz`
clang version is `Apple LLVM version 9.0.0 (clang-900.0.39.2)`
gcc-5 version is `gcc-5 (Homebrew GCC 5.5.0) 5.5.0`
gcc-7 version is `gcc-7 (Homebrew GCC 7.2.0) 7.2.0`
Here are the results in comparison to libjpeg-turbo@293263c using
`time ./jpegtran -outfile /dev/null -progressive -optimise -copy none print_poster_0025.jpg`
C
clang x86_64: +19%
gcc-5 x86_64: +80%
gcc-7 x86_64: +57%
clang i386: +5%
gcc-5 i386: +59%
gcc-7 i386: +51%
SSE2
clang x86_64: +79%
gcc-5 x86_64: +158%
gcc-7 x86_64: +122%
clang i386: +71%
gcc-5 i386: +134%
gcc-7 i386: +135%
Discussion in libjpeg-turbo/libjpeg-turbo#46
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16bd9845
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2018-03-02T22:33:19
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C/SSE2 optimization of encode_mcu_AC_refine()
This commit adds C and SSE2 optimizations for the encode_mcu_AC_refine()
function used in progressive Huffman encoding.
The image used for testing can be retrieved from this page:
https://blog.cloudflare.com/doubling-the-speed-of-jpegtran
All timings done on `Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz`
clang version is `Apple LLVM version 9.0.0 (clang-900.0.39.2)`
gcc-5 version is `gcc-5 (Homebrew GCC 5.5.0) 5.5.0`
gcc-7 version is `gcc-7 (Homebrew GCC 7.2.0) 7.2.0`
Here are the results in comparison to libjpeg-turbo@3c54642 using
`time ./jpegtran -outfile /dev/null -progressive -optimise -copy none print_poster_0025.jpg`
C
clang x86_64: +7%
gcc-5 x86_64: +30%
gcc-7 x86_64: +33%
clang i386: +0%
gcc-5 i386: +24%
gcc-7 i386: +23%
SSE2
clang x86_64: +42%
gcc-5 x86_64: +53%
gcc-7 x86_64: +64%
clang i386: +35%
gcc-5 i386: +46%
gcc-7 i386: +49%
Discussion in libjpeg-turbo/libjpeg-turbo#46
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81baa1b5
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2018-03-21T13:03:30
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simd/i386/jchuff-sse2.asm: Minor formatting tweak
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293263c3
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2018-03-17T15:14:35
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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.
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84fbd4f1
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2018-03-17T00:27:49
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Merge branch 'master' into dev
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19c791cd
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2018-03-08T10:55:20
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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.
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35ed3c97
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2018-02-28T16:24:03
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SIMD: Formatting tweaks + remove unnecessary code
+ "JSIMD_ARM_NEON" = "JSIMD_NEON"
+ "JSIMD_MIPS_DSPR2" = "JSIMD_DSPR2"
+ "*_mips_dspr2" = "*_dspr2"
It's obvious that "NEON" refers to Arm and "DSPr2" refers to MIPS, and
this naming convention is consistent with the other SIMD extensions.
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feaec37d
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2018-02-24T14:20:59
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Fix build with YASM
vinserti128 requires all operands to be specified
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88421563
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2018-02-23T21:56:32
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Make SIMD symbols private for x86[-64] ELF builds
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9cdec16c
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2018-02-23T13:58:24
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32-bit AVX2 implementation of slow int inverse DCT
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845fe8bf
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2018-02-23T12:24:10
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32-bit AVX2 buglet: IS_ALIGNED_SSE=IS_ALIGNED_AVX
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715b7c38
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2018-02-17T22:15:58
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32-bit AVX2 implementation of int sample conv.
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ca387e7f
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2018-02-17T20:31:30
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32-bit AVX2 implementation of slow int forward DCT
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ff392d81
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2018-02-17T17:29:38
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AVX2: Introduce YMMBLOCK macro for readability
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c0f3512d
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2017-08-31T20:57:19
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Merge branch 'master' into dev
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6abd3916
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2016-11-15T08:47:43
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Unified CMake-based build system
See #56 for discussion.
Fixes #21, Fixes #29, Fixes #37, Closes #56, Fixes #58, Closes #73
Obviates #82
See also:
https://sourceforge.net/p/libjpeg-turbo/feature-requests/5/
https://sourceforge.net/p/libjpeg-turbo/patches/5/
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