Update libjpeg-turbo to r856.

ChangeLog.txt

Index: ChangeLog.txt
===================================================================
--- ChangeLog.txt	(revision 144411)
+++ ChangeLog.txt	(working copy)
@@ -5,32 +5,66 @@
 11/8, 3/2, 13/8, 7/4, 15/8, and 2) when decompressing.  Note that the IDCT will
 not be SIMD-accelerated when using any of these new scaling factors.
 
-[2] Added SIMD acceleration for performing 4:2:2 upsampling on NEON-capable ARM
-platforms.  This speeds up the decompression of 4:2:2 JPEGs by 20-25% on such
-platforms.
+[2] The TurboJPEG dynamic library is now versioned.  It was not strictly
+necessary to do so, because TurboJPEG uses versioned symbols, and if a function
+changes in an ABI-incompatible way, that function is renamed and a legacy
+function is provided to maintain backward compatibility.  However, certain
+Linux distro maintainers will blindly reject any library that is not versioned,
+so this was an attempt to make them happy.
 
-[3] Creating or decoding a JPEG file that uses the RGB colorspace should now
+[3] Extended the TurboJPEG Java API so that it can be used to decompress a
+JPEG image into an arbitrary position in a large output buffer.
+
+[4] The tjDecompressToYUV() function now supports the TJFLAG_FASTDCT flag.
+
+
+1.2.1
+=====
+
+[1] Creating or decoding a JPEG file that uses the RGB colorspace should now
 properly work when the input or output colorspace is one of the libjpeg-turbo
 colorspace extensions.
 
-[4] When libjpeg-turbo was built without SIMD support and merged (non-fancy)
+[2] When libjpeg-turbo was built without SIMD support and merged (non-fancy)
 upsampling was used along with an alpha-enabled colorspace during
 decompression, the unused byte of the decompressed pixels was not being set to
 0xFF.  This has been fixed.  TJUnitTest has also been extended to test for the
 correct behavior of the colorspace extensions when merged upsampling is used.
 
-[5] The TurboJPEG dynamic library is now versioned.  It was not strictly
-necessary to do so, because TurboJPEG uses versioned symbols, and if a function
-changes in an ABI-incompatible way, that function is renamed and a legacy
-function is provided to maintain backward compatibility.  However, certain
-Linux distro maintainers will blindly reject any library that is not versioned,
-so this was an attempt to make them happy.
-
-[6] Fixed a bug whereby the libjpeg-turbo SSE2 SIMD code would not preserve the
+[3] Fixed a bug whereby the libjpeg-turbo SSE2 SIMD code would not preserve the
 upper 64 bits of xmm6 and xmm7 on Win64 platforms, which violated the Win64
 calling conventions.
 
+[4] Fixed a regression caused by 1.2.0[6] whereby decompressing corrupt JPEG
+images (specifically, images in which the component count was erroneously set
+to a large value) would cause libjpeg-turbo to segfault.
 
+[5] Worked around a severe performance issue with "Bobcat" (AMD Embedded APU)
+processors.  The MASKMOVDQU instruction, which was used by the libjpeg-turbo
+SSE2 SIMD code, is apparently implemented in microcode on AMD processors, and
+it is painfully slow on Bobcat processors in particular.  Eliminating the use
+of this instruction improved performance by an order of magnitude on Bobcat
+processors and by a small amount (typically 5%) on AMD desktop processors.
+
+[6] Added SIMD acceleration for performing 4:2:2 upsampling on NEON-capable ARM
+platforms.  This speeds up the decompression of 4:2:2 JPEGs by 20-25% on such
+platforms.
+
+[7] Fixed a regression caused by 1.2.0[2] whereby, on Linux/x86 platforms
+running the 32-bit SSE2 SIMD code in libjpeg-turbo, decompressing a 4:2:0 or
+4:2:2 JPEG image into a 32-bit (RGBX, BGRX, etc.) buffer without using fancy
+upsampling would produce several incorrect columns of pixels at the right-hand
+side of the output image if each row in the output image was not evenly
+divisible by 16 bytes.
+
+[8] Fixed an issue whereby attempting to build the SIMD extensions with Xcode
+4.3 on OS X platforms would cause NASM to return numerous errors of the form
+"'%define' expects a macro identifier".
+
+[9] Added flags to the TurboJPEG API that allow the caller to force the use of
+either the fast or the accurate DCT/IDCT algorithms in the underlying codec.
+
+
 1.2.0
 =====