96 lines
1.5 KiB
C
96 lines
1.5 KiB
C
/*
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* p2d_copy.c - Copy a polygon, with or without reversing it
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*
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* Written 2012 by Werner Almesberger
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* Copyright 2012 Werner Almesberger
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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 2.1 of the License, or (at your option) any later version.
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*/
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#include <math.h>
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#include "util.h"
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#include "poly2d.h"
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struct p2d *p2d_copy(const struct p2d *p)
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{
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struct p2d *np;
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const struct v2d *v;
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struct v2d *nv, **last;
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np = alloc_type(struct p2d);
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np->v = NULL;
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np->last = NULL;
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np->next = NULL;
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last = &np->v;
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v = p->v;
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while (v) {
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nv = alloc_type(struct v2d);
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nv->x = v->x;
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nv->y = v->y;
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nv->next = NULL;
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*last = nv;
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last = &nv->next;
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np->last = nv;
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v = v->next;
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if (v == p->v)
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break;
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}
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if (v)
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*last = np->v;
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return np;
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}
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struct p2d *p2d_copy_all(const struct p2d *p)
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{
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struct p2d *res = NULL, **last = &res;
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while (p) {
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*last = p2d_copy(p);
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last = &(*last)->next;
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p = p->next;
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}
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return res;
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}
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struct p2d *p2d_reverse(const struct p2d *p)
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{
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struct p2d *np;
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const struct v2d *v;
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struct v2d *nv;
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np = alloc_type(struct p2d);
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np->v = NULL;
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np->last = NULL;
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np->next = NULL;
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v = p->v;
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while (v) {
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nv = alloc_type(struct v2d);
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nv->x = v->x;
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nv->y = v->y;
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nv->next = np->v;
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np->v = nv;
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if (!np->last)
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np->last= nv;
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v = v->next;
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if (v == p->v)
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break;
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}
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if (v && np->last)
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np->last->next = np->v;
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return np;
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}
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