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https://github.com/python-pillow/Pillow.git
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317 lines
7.9 KiB
C
317 lines
7.9 KiB
C
/*
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* The Python Imaging Library
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* $Id$
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*
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* helpers to bounding boxes, min/max values, number of colors, etc.
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*
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* history:
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* 1996-07-22 fl Created
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* 1996-12-30 fl Added projection stuff
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* 1998-07-12 fl Added extrema stuff
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* 2004-09-17 fl Added colors stuff
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*
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* Copyright (c) 1997-2004 by Secret Labs AB.
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* Copyright (c) 1996-2004 by Fredrik Lundh.
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*
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* See the README file for details on usage and redistribution.
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*/
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#include "Imaging.h"
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int
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ImagingGetBBox(Imaging im, int bbox[4])
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{
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/* Get the bounding box for any non-zero data in the image.*/
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int x, y;
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int has_data;
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/* Initialize bounding box to max values */
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bbox[0] = im->xsize;
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bbox[1] = -1;
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bbox[2] = bbox[3] = 0;
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#define GETBBOX(image, mask)\
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for (y = 0; y < im->ysize; y++) {\
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has_data = 0;\
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for (x = 0; x < im->xsize; x++)\
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if (im->image[y][x] & mask) {\
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has_data = 1;\
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if (x < bbox[0])\
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bbox[0] = x;\
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if (x >= bbox[2])\
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bbox[2] = x+1;\
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}\
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if (has_data) {\
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if (bbox[1] < 0)\
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bbox[1] = y;\
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bbox[3] = y+1;\
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}\
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}
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if (im->image8) {
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GETBBOX(image8, 0xff);
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} else {
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INT32 mask = 0xffffffff;
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if (im->bands == 3)
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((UINT8*) &mask)[3] = 0;
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GETBBOX(image32, mask);
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}
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/* Check that we got a box */
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if (bbox[1] < 0)
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return 0; /* no data */
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return 1; /* ok */
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}
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int
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ImagingGetProjection(Imaging im, UINT8* xproj, UINT8* yproj)
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{
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/* Get projection arrays for non-zero data in the image.*/
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int x, y;
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int has_data;
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/* Initialize projection arrays */
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memset(xproj, 0, im->xsize);
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memset(yproj, 0, im->ysize);
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#define GETPROJ(image, mask)\
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for (y = 0; y < im->ysize; y++) {\
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has_data = 0;\
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for (x = 0; x < im->xsize; x++)\
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if (im->image[y][x] & mask) {\
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has_data = 1;\
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xproj[x] = 1;\
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}\
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if (has_data)\
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yproj[y] = 1;\
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}
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if (im->image8) {
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GETPROJ(image8, 0xff);
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} else {
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INT32 mask = 0xffffffff;
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if (im->bands == 3)
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((UINT8*) &mask)[3] = 0;
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GETPROJ(image32, mask);
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}
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return 1; /* ok */
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}
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int
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ImagingGetExtrema(Imaging im, void *extrema)
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{
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int x, y;
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INT32 imin, imax;
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FLOAT32 fmin, fmax;
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if (im->bands != 1) {
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(void) ImagingError_ModeError();
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return -1; /* mismatch */
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}
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if (!im->xsize || !im->ysize)
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return 0; /* zero size */
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switch (im->type) {
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case IMAGING_TYPE_UINT8:
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imin = imax = im->image8[0][0];
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for (y = 0; y < im->ysize; y++) {
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UINT8* in = im->image8[y];
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for (x = 0; x < im->xsize; x++) {
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if (imin > in[x])
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imin = in[x];
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else if (imax < in[x])
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imax = in[x];
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}
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}
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((UINT8*) extrema)[0] = (UINT8) imin;
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((UINT8*) extrema)[1] = (UINT8) imax;
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break;
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case IMAGING_TYPE_INT32:
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imin = imax = im->image32[0][0];
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for (y = 0; y < im->ysize; y++) {
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INT32* in = im->image32[y];
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for (x = 0; x < im->xsize; x++) {
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if (imin > in[x])
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imin = in[x];
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else if (imax < in[x])
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imax = in[x];
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}
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}
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((INT32*) extrema)[0] = imin;
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((INT32*) extrema)[1] = imax;
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break;
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case IMAGING_TYPE_FLOAT32:
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fmin = fmax = ((FLOAT32*) im->image32[0])[0];
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for (y = 0; y < im->ysize; y++) {
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FLOAT32* in = (FLOAT32*) im->image32[y];
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for (x = 0; x < im->xsize; x++) {
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if (fmin > in[x])
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fmin = in[x];
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else if (fmax < in[x])
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fmax = in[x];
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}
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}
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((FLOAT32*) extrema)[0] = fmin;
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((FLOAT32*) extrema)[1] = fmax;
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break;
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case IMAGING_TYPE_SPECIAL:
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if (strcmp(im->mode, "I;16") == 0) {
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imin = imax = ((UINT16*) im->image8[0])[0];
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for (y = 0; y < im->ysize; y++) {
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UINT16* in = (UINT16 *) im->image[y];
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for (x = 0; x < im->xsize; x++) {
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if (imin > in[x])
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imin = in[x];
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else if (imax < in[x])
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imax = in[x];
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}
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}
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((UINT16*) extrema)[0] = (UINT16) imin;
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((UINT16*) extrema)[1] = (UINT16) imax;
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break;
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}
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/* FALL THROUGH */
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default:
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(void) ImagingError_ModeError();
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return -1;
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}
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return 1; /* ok */
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}
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/* static ImagingColorItem* getcolors8(Imaging im, int maxcolors, int* size);*/
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static ImagingColorItem* getcolors32(Imaging im, int maxcolors, int* size);
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ImagingColorItem*
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ImagingGetColors(Imaging im, int maxcolors, int* size)
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{
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/* FIXME: add support for 8-bit images */
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return getcolors32(im, maxcolors, size);
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}
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static ImagingColorItem*
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getcolors32(Imaging im, int maxcolors, int* size)
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{
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unsigned int h;
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unsigned int i, incr;
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int colors;
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INT32 pixel_mask;
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int x, y;
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ImagingColorItem* table;
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ImagingColorItem* v;
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unsigned int code_size;
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unsigned int code_poly;
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unsigned int code_mask;
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/* note: the hash algorithm used here is based on the dictionary
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code in Python 2.1.3; the exact implementation is borrowed from
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Python's Unicode property database (written by yours truly) /F */
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static int SIZES[] = {
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4,3, 8,3, 16,3, 32,5, 64,3, 128,3, 256,29, 512,17, 1024,9, 2048,5,
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4096,83, 8192,27, 16384,43, 32768,3, 65536,45, 131072,9, 262144,39,
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524288,39, 1048576,9, 2097152,5, 4194304,3, 8388608,33, 16777216,27,
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33554432,9, 67108864,71, 134217728,39, 268435456,9, 536870912,5,
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1073741824,83, 0
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};
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code_size = code_poly = code_mask = 0;
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for (i = 0; SIZES[i]; i += 2) {
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if (SIZES[i] > maxcolors) {
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code_size = SIZES[i];
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code_poly = SIZES[i+1];
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code_mask = code_size - 1;
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break;
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}
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}
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/* printf("code_size=%d\n", code_size); */
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/* printf("code_poly=%d\n", code_poly); */
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if (!code_size)
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return ImagingError_MemoryError(); /* just give up */
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if (!im->image32)
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return ImagingError_ModeError();
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table = calloc(code_size + 1, sizeof(ImagingColorItem));
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if (!table)
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return ImagingError_MemoryError();
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pixel_mask = 0xffffffff;
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if (im->bands == 3)
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((UINT8*) &pixel_mask)[3] = 0;
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colors = 0;
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for (y = 0; y < im->ysize; y++) {
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INT32* p = im->image32[y];
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for (x = 0; x < im->xsize; x++) {
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INT32 pixel = p[x] & pixel_mask;
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h = (pixel); /* null hashing */
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i = (~h) & code_mask;
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v = &table[i];
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if (!v->count) {
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/* add to table */
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if (colors++ == maxcolors)
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goto overflow;
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v->x = x; v->y = y;
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v->pixel = pixel;
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v->count = 1;
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continue;
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} else if (v->pixel == pixel) {
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v->count++;
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continue;
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}
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incr = (h ^ (h >> 3)) & code_mask;
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if (!incr)
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incr = code_mask;
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for (;;) {
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i = (i + incr) & code_mask;
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v = &table[i];
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if (!v->count) {
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/* add to table */
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if (colors++ == maxcolors)
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goto overflow;
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v->x = x; v->y = y;
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v->pixel = pixel;
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v->count = 1;
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break;
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} else if (v->pixel == pixel) {
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v->count++;
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break;
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}
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incr = incr << 1;
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if (incr > code_mask)
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incr = incr ^ code_poly;
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}
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}
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}
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overflow:
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/* pack the table */
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for (x = y = 0; x < (int) code_size; x++)
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if (table[x].count) {
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if (x != y)
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table[y] = table[x];
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y++;
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}
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table[y].count = 0; /* mark end of table */
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*size = colors;
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return table;
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}
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