зеркало из https://github.com/mozilla/mozjpeg.git
227 строки
8.5 KiB
C
227 строки
8.5 KiB
C
/* Copyright (C)2004 Landmark Graphics Corporation
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* Copyright (C)2005, 2006 Sun Microsystems, Inc.
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* Copyright (C)2009 D. R. Commander
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*
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* This library is free software and may be redistributed and/or modified under
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* the terms of the wxWindows Library License, Version 3.1 or (at your option)
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* any later version. The full license is in the LICENSE.txt file included
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* with this distribution.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* wxWindows Library License for more details.
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*/
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#if (defined(_MSC_VER) || defined(__CYGWIN__) || defined(__MINGW32__)) && defined(_WIN32) && defined(DLLDEFINE)
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#define DLLEXPORT __declspec(dllexport)
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#else
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#define DLLEXPORT
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#endif
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#define DLLCALL
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/* Subsampling */
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#define NUMSUBOPT 4
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enum {TJ_444=0, TJ_422, TJ_420, TJ_GRAYSCALE};
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#define TJ_411 TJ_420 /* for backward compatibility with VirtualGL <= 2.1.x,
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TurboVNC <= 0.6, and TurboJPEG/IPP */
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/* Flags */
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#define TJ_BGR 1
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/* The components of each pixel in the source/destination bitmap are stored
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in B,G,R order, not R,G,B */
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#define TJ_BOTTOMUP 2
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/* The source/destination bitmap is stored in bottom-up (Windows, OpenGL)
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order, not top-down (X11) order */
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#define TJ_FORCEMMX 8
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/* Turn off CPU auto-detection and force TurboJPEG to use MMX code
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(IPP and 32-bit libjpeg-turbo versions only) */
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#define TJ_FORCESSE 16
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/* Turn off CPU auto-detection and force TurboJPEG to use SSE code
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(32-bit IPP and 32-bit libjpeg-turbo versions only) */
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#define TJ_FORCESSE2 32
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/* Turn off CPU auto-detection and force TurboJPEG to use SSE2 code
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(32-bit IPP and 32-bit libjpeg-turbo versions only) */
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#define TJ_ALPHAFIRST 64
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/* If the source/destination bitmap is 32 bpp, assume that each pixel is
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ARGB/XRGB (or ABGR/XBGR if TJ_BGR is also specified) */
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#define TJ_FORCESSE3 128
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/* Turn off CPU auto-detection and force TurboJPEG to use SSE3 code
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(64-bit IPP version only) */
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#define TJ_FASTUPSAMPLE 256
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/* Use fast, inaccurate 4:2:2 and 4:2:0 YUV upsampling routines
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(libjpeg version only) */
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typedef void* tjhandle;
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#define TJPAD(p) (((p)+3)&(~3))
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#ifndef max
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#define max(a,b) ((a)>(b)?(a):(b))
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* API follows */
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/*
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tjhandle tjInitCompress(void)
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Creates a new JPEG compressor instance, allocates memory for the structures,
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and returns a handle to the instance. Most applications will only
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need to call this once at the beginning of the program or once for each
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concurrent thread. Don't try to create a new instance every time you
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compress an image, because this will cause performance to suffer.
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RETURNS: NULL on error
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*/
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DLLEXPORT tjhandle DLLCALL tjInitCompress(void);
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/*
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int tjCompress(tjhandle j,
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unsigned char *srcbuf, int width, int pitch, int height, int pixelsize,
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unsigned char *dstbuf, unsigned long *size,
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int jpegsubsamp, int jpegqual, int flags)
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[INPUT] j = instance handle previously returned from a call to
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tjInitCompress()
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[INPUT] srcbuf = pointer to user-allocated image buffer containing pixels in
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RGB(A) or BGR(A) form
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[INPUT] width = width (in pixels) of the source image
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[INPUT] pitch = bytes per line of the source image (width*pixelsize if the
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bitmap is unpadded, else TJPAD(width*pixelsize) if each line of the bitmap
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is padded to the nearest 32-bit boundary, such as is the case for Windows
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bitmaps. You can also be clever and use this parameter to skip lines, etc.,
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as long as the pitch is greater than 0.)
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[INPUT] height = height (in pixels) of the source image
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[INPUT] pixelsize = size (in bytes) of each pixel in the source image
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RGBA and BGRA: 4, RGB and BGR: 3
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[INPUT] dstbuf = pointer to user-allocated image buffer which will receive
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the JPEG image. Use the macro TJBUFSIZE(width, height) to determine
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the appropriate size for this buffer based on the image width and height.
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[OUTPUT] size = pointer to unsigned long which receives the size (in bytes)
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of the compressed image
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[INPUT] jpegsubsamp = Specifies either 4:2:0, 4:2:2, or 4:4:4 subsampling.
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When the image is converted from the RGB to YCbCr colorspace as part of the
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JPEG compression process, every other Cb and Cr (chrominance) pixel can be
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discarded to produce a smaller image with little perceptible loss of
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image clarity (the human eye is more sensitive to small changes in
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brightness than small changes in color.)
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TJ_420: 4:2:0 subsampling. Discards every other Cb, Cr pixel in both
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horizontal and vertical directions.
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TJ_422: 4:2:2 subsampling. Discards every other Cb, Cr pixel only in
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the horizontal direction.
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TJ_444: no subsampling.
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TJ_GRAYSCALE: Generate grayscale JPEG image
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[INPUT] jpegqual = JPEG quality (an integer between 0 and 100 inclusive.)
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[INPUT] flags = the bitwise OR of one or more of the flags described in the
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"Flags" section above.
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RETURNS: 0 on success, -1 on error
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*/
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DLLEXPORT int DLLCALL tjCompress(tjhandle j,
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unsigned char *srcbuf, int width, int pitch, int height, int pixelsize,
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unsigned char *dstbuf, unsigned long *size,
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int jpegsubsamp, int jpegqual, int flags);
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DLLEXPORT unsigned long DLLCALL TJBUFSIZE(int width, int height);
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/*
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tjhandle tjInitDecompress(void)
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Creates a new JPEG decompressor instance, allocates memory for the
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structures, and returns a handle to the instance. Most applications will
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only need to call this once at the beginning of the program or once for each
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concurrent thread. Don't try to create a new instance every time you
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decompress an image, because this will cause performance to suffer.
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RETURNS: NULL on error
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*/
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DLLEXPORT tjhandle DLLCALL tjInitDecompress(void);
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/*
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int tjDecompressHeader(tjhandle j,
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unsigned char *srcbuf, unsigned long size,
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int *width, int *height)
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[INPUT] j = instance handle previously returned from a call to
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tjInitDecompress()
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[INPUT] srcbuf = pointer to a user-allocated buffer containing the JPEG image
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to decompress
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[INPUT] size = size of the JPEG image buffer (in bytes)
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[OUTPUT] width = width (in pixels) of the JPEG image
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[OUTPUT] height = height (in pixels) of the JPEG image
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RETURNS: 0 on success, -1 on error
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*/
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DLLEXPORT int DLLCALL tjDecompressHeader(tjhandle j,
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unsigned char *srcbuf, unsigned long size,
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int *width, int *height);
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/*
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int tjDecompress(tjhandle j,
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unsigned char *srcbuf, unsigned long size,
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unsigned char *dstbuf, int width, int pitch, int height, int pixelsize,
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int flags)
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[INPUT] j = instance handle previously returned from a call to
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tjInitDecompress()
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[INPUT] srcbuf = pointer to a user-allocated buffer containing the JPEG image
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to decompress
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[INPUT] size = size of the JPEG image buffer (in bytes)
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[INPUT] dstbuf = pointer to user-allocated image buffer which will receive
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the bitmap image. This buffer should normally be pitch*height
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bytes in size, although this pointer may also be used to decompress into
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a specific region of a larger buffer.
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[INPUT] width = width (in pixels) of the destination image
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[INPUT] pitch = bytes per line of the destination image (width*pixelsize if the
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bitmap is unpadded, else TJPAD(width*pixelsize) if each line of the bitmap
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is padded to the nearest 32-bit boundary, such as is the case for Windows
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bitmaps. You can also be clever and use this parameter to skip lines, etc.,
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as long as the pitch is greater than 0.)
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[INPUT] height = height (in pixels) of the destination image
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[INPUT] pixelsize = size (in bytes) of each pixel in the destination image
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RGBA/RGBx and BGRA/BGRx: 4, RGB and BGR: 3
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[INPUT] flags = the bitwise OR of one or more of the flags described in the
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"Flags" section above.
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RETURNS: 0 on success, -1 on error
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*/
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DLLEXPORT int DLLCALL tjDecompress(tjhandle j,
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unsigned char *srcbuf, unsigned long size,
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unsigned char *dstbuf, int width, int pitch, int height, int pixelsize,
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int flags);
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/*
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int tjDestroy(tjhandle h)
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Frees structures associated with a compression or decompression instance
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[INPUT] h = instance handle (returned from a previous call to
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tjInitCompress() or tjInitDecompress()
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RETURNS: 0 on success, -1 on error
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*/
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DLLEXPORT int DLLCALL tjDestroy(tjhandle h);
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/*
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char *tjGetErrorStr(void)
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Returns a descriptive error message explaining why the last command failed
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*/
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DLLEXPORT char* DLLCALL tjGetErrorStr(void);
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#ifdef __cplusplus
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}
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#endif
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