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| 1 | /* |
| 2 | * p2d_copy.c - Copy a polygon, with or without reversing it |
| 3 | * |
| 4 | * Written 2012 by Werner Almesberger |
| 5 | * Copyright 2012 Werner Almesberger |
| 6 | * |
| 7 | * This library is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU Lesser General Public |
| 9 | * License as published by the Free Software Foundation; either |
| 10 | * version 2.1 of the License, or (at your option) any later version. |
| 11 | */ |
| 12 | |
| 13 | |
| 14 | #include <math.h> |
| 15 | |
| 16 | #include "util.h" |
| 17 | #include "poly2d.h" |
| 18 | |
| 19 | |
| 20 | struct p2d *p2d_copy(const struct p2d *p) |
| 21 | { |
| 22 | struct p2d *np; |
| 23 | const struct v2d *v; |
| 24 | struct v2d *nv, **last; |
| 25 | |
| 26 | np = alloc_type(struct p2d); |
| 27 | np->v = NULL; |
| 28 | np->last = NULL; |
| 29 | np->next = NULL; |
| 30 | |
| 31 | last = &np->v; |
| 32 | v = p->v; |
| 33 | while (v) { |
| 34 | nv = alloc_type(struct v2d); |
| 35 | nv->x = v->x; |
| 36 | nv->y = v->y; |
| 37 | nv->next = NULL; |
| 38 | *last = nv; |
| 39 | last = &nv->next; |
| 40 | |
| 41 | np->last = nv; |
| 42 | |
| 43 | v = v->next; |
| 44 | if (v == p->v) |
| 45 | break; |
| 46 | } |
| 47 | if (v) |
| 48 | *last = np->v; |
| 49 | return np; |
| 50 | } |
| 51 | |
| 52 | |
| 53 | struct p2d *p2d_copy_all(const struct p2d *p) |
| 54 | { |
| 55 | struct p2d *res = NULL, **last = &res; |
| 56 | |
| 57 | while (p) { |
| 58 | *last = p2d_copy(p); |
| 59 | last = &(*last)->next; |
| 60 | p = p->next; |
| 61 | } |
| 62 | return res; |
| 63 | } |
| 64 | |
| 65 | |
| 66 | struct p2d *p2d_reverse(const struct p2d *p) |
| 67 | { |
| 68 | struct p2d *np; |
| 69 | const struct v2d *v; |
| 70 | struct v2d *nv; |
| 71 | |
| 72 | np = alloc_type(struct p2d); |
| 73 | np->v = NULL; |
| 74 | np->last = NULL; |
| 75 | np->next = NULL; |
| 76 | |
| 77 | v = p->v; |
| 78 | while (v) { |
| 79 | nv = alloc_type(struct v2d); |
| 80 | nv->x = v->x; |
| 81 | nv->y = v->y; |
| 82 | nv->next = np->v; |
| 83 | np->v = nv; |
| 84 | |
| 85 | if (!np->last) |
| 86 | np->last= nv; |
| 87 | |
| 88 | v = v->next; |
| 89 | if (v == p->v) |
| 90 | break; |
| 91 | } |
| 92 | if (v && np->last) |
| 93 | np->last->next = np->v; |
| 94 | return np; |
| 95 | } |
| 96 |
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