74 lines
1.1 KiB
C
74 lines
1.1 KiB
C
/*
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* p2d_make.c - Polygon creation
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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 <assert.h>
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#include "util.h"
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#include "poly2d.h"
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struct p2d *p2d_new(void)
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{
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struct p2d *np;
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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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return np;
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}
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struct v2d *v2d_new(double x, double y)
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{
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struct v2d *nv;
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nv = alloc_type(struct v2d);
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nv->x = x;
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nv->y = y;
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nv->next = NULL;
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return nv;
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}
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void p2d_append(struct p2d *p, struct v2d *v)
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{
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if (p->last && p->last->next)
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v->next = p->v;
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if (p->last)
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p->last->next = v;
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else
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p->v = v;
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p->last = v;
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}
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void p2d_prepend(struct p2d *p, struct v2d *v)
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{
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v->next = p->v;
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p->v = v;
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if (p->last) {
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if (p->last->next)
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p->last->next = v;
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} else {
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p->last = v;
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}
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}
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void p2d_close(struct p2d *p)
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{
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assert(!p->v || !p->last->next);
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p->last->next = p->v;
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}
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