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3c618f2f1f
If e.g. the right edge of the leftmost rectangle is near MIN_INT, and the left edge of the rightmost rectangle is large then subtracting these can lead to an integer overflow, making the resultant "width" falsely positive, thus returning a very wide result instead of the expected no-intersection result. We avoid the overflow by not doing the subtraction unless we know the result will be positive. There are still risks for overflow if x + width or y + width is larger than MAXINT, but we won't ever overflow for valid rects now. This may fix #607687
139 lines
3.9 KiB
C
139 lines
3.9 KiB
C
/* GDK - The GIMP Drawing Kit
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* Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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/*
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* Modified by the GTK+ Team and others 1997-2000. See the AUTHORS
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* file for a list of people on the GTK+ Team. See the ChangeLog
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* files for a list of changes. These files are distributed with
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* GTK+ at ftp://ftp.gtk.org/pub/gtk/.
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*/
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#include "config.h"
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#include <gdk/gdk.h>
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#include "gdkalias.h"
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/**
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* gdk_rectangle_union:
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* @src1: a #GdkRectangle
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* @src2: a #GdkRectangle
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* @dest: return location for the union of @src1 and @src2
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*
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* Calculates the union of two rectangles.
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* The union of rectangles @src1 and @src2 is the smallest rectangle which
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* includes both @src1 and @src2 within it.
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* It is allowed for @dest to be the same as either @src1 or @src2.
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*/
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void
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gdk_rectangle_union (const GdkRectangle *src1,
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const GdkRectangle *src2,
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GdkRectangle *dest)
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{
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gint dest_x, dest_y;
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g_return_if_fail (src1 != NULL);
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g_return_if_fail (src2 != NULL);
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g_return_if_fail (dest != NULL);
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dest_x = MIN (src1->x, src2->x);
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dest_y = MIN (src1->y, src2->y);
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dest->width = MAX (src1->x + src1->width, src2->x + src2->width) - dest_x;
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dest->height = MAX (src1->y + src1->height, src2->y + src2->height) - dest_y;
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dest->x = dest_x;
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dest->y = dest_y;
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}
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/**
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* gdk_rectangle_intersect:
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* @src1: a #GdkRectangle
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* @src2: a #GdkRectangle
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* @dest: return location for the intersection of @src1 and @src2, or %NULL
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*
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* Calculates the intersection of two rectangles. It is allowed for
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* @dest to be the same as either @src1 or @src2. If the rectangles
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* do not intersect, @dest's width and height is set to 0 and its x
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* and y values are undefined. If you are only interested in whether
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* the rectangles intersect, but not in the intersecting area itself,
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* pass %NULL for @dest.
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*
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* Returns: %TRUE if the rectangles intersect.
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*/
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gboolean
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gdk_rectangle_intersect (const GdkRectangle *src1,
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const GdkRectangle *src2,
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GdkRectangle *dest)
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{
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gint dest_x, dest_y;
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gint dest_x2, dest_y2;
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gint return_val;
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g_return_val_if_fail (src1 != NULL, FALSE);
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g_return_val_if_fail (src2 != NULL, FALSE);
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return_val = FALSE;
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dest_x = MAX (src1->x, src2->x);
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dest_y = MAX (src1->y, src2->y);
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dest_x2 = MIN (src1->x + src1->width, src2->x + src2->width);
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dest_y2 = MIN (src1->y + src1->height, src2->y + src2->height);
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if (dest_x2 > dest_x && dest_y2 > dest_y)
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{
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if (dest)
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{
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dest->x = dest_x;
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dest->y = dest_y;
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dest->width = dest_x2 - dest_x;
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dest->height = dest_y2 - dest_y;
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}
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return_val = TRUE;
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}
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else if (dest)
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{
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dest->width = 0;
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dest->height = 0;
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}
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return return_val;
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}
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static GdkRectangle *
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gdk_rectangle_copy (const GdkRectangle *rectangle)
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{
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GdkRectangle *result = g_new (GdkRectangle, 1);
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*result = *rectangle;
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return result;
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}
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GType
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gdk_rectangle_get_type (void)
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{
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static GType our_type = 0;
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if (our_type == 0)
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our_type = g_boxed_type_register_static (g_intern_static_string ("GdkRectangle"),
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(GBoxedCopyFunc)gdk_rectangle_copy,
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(GBoxedFreeFunc)g_free);
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return our_type;
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}
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#define __GDK_RECTANGLE_C__
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#include "gdkaliasdef.c"
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