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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 10 | reyssat | 1 | |
| 2 | /*** EDGELIST.C ***/ |
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| 3 | |||
| 4 | #include "vdefs.h" |
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| 5 | |||
| 6 | int ELhashsize ; |
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| 7 | Site * bottomsite ; |
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| 8 | Freelist hfl ; |
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| 9 | Halfedge * ELleftend, * ELrightend, **ELhash ; |
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| 10 | |||
| 11 | int ntry, totalsearch ; |
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| 12 | |||
| 13 | void |
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| 14 | ELinitialize(void) |
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| 15 | { |
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| 16 | int i ; |
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| 17 | |||
| 18 | freeinit(&hfl, sizeof(Halfedge)) ; |
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| 19 | ELhashsize = 2 * sqrt_nsites ; |
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| 20 | ELhash = (Halfedge **)myalloc( sizeof(*ELhash) * ELhashsize) ; |
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| 21 | for (i = 0 ; i < ELhashsize ; i++) |
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| 22 | { |
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| 23 | ELhash[i] = (Halfedge *)NULL ; |
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| 24 | } |
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| 25 | ELleftend = HEcreate((Edge *)NULL, 0) ; |
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| 26 | ELrightend = HEcreate((Edge *)NULL, 0) ; |
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| 27 | ELleftend->ELleft = (Halfedge *)NULL ; |
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| 28 | ELleftend->ELright = ELrightend ; |
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| 29 | ELrightend->ELleft = ELleftend ; |
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| 30 | ELrightend->ELright = (Halfedge *)NULL ; |
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| 31 | ELhash[0] = ELleftend ; |
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| 32 | ELhash[ELhashsize-1] = ELrightend ; |
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| 33 | } |
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| 34 | |||
| 35 | Halfedge * |
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| 36 | HEcreate(Edge * e, int pm) |
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| 37 | { |
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| 38 | Halfedge * answer ; |
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| 39 | |||
| 40 | answer = (Halfedge *)getfree(&hfl) ; |
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| 41 | answer->ELedge = e ; |
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| 42 | answer->ELpm = pm ; |
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| 43 | answer->PQnext = (Halfedge *)NULL ; |
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| 44 | answer->vertex = (Site *)NULL ; |
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| 45 | answer->ELrefcnt = 0 ; |
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| 46 | return (answer) ; |
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| 47 | } |
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| 48 | |||
| 49 | void |
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| 50 | ELinsert(Halfedge * lb, Halfedge * new) |
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| 51 | { |
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| 52 | new->ELleft = lb ; |
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| 53 | new->ELright = lb->ELright ; |
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| 54 | (lb->ELright)->ELleft = new ; |
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| 55 | lb->ELright = new ; |
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| 56 | } |
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| 57 | |||
| 58 | /* Get entry from hash table, pruning any deleted nodes */ |
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| 59 | |||
| 60 | Halfedge * |
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| 61 | ELgethash(int b) |
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| 62 | { |
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| 63 | Halfedge * he ; |
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| 64 | |||
| 65 | if ((b < 0) || (b >= ELhashsize)) |
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| 66 | { |
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| 67 | return ((Halfedge *)NULL) ; |
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| 68 | } |
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| 69 | he = ELhash[b] ; |
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| 70 | if ((he == (Halfedge *)NULL) || (he->ELedge != (Edge *)DELETED)) |
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| 71 | { |
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| 72 | return (he) ; |
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| 73 | } |
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| 74 | /* Hash table points to deleted half edge. Patch as necessary. */ |
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| 75 | ELhash[b] = (Halfedge *)NULL ; |
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| 76 | if ((--(he->ELrefcnt)) == 0) |
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| 77 | { |
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| 78 | makefree((Freenode *)he, (Freelist *)&hfl) ; |
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| 79 | } |
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| 80 | return ((Halfedge *)NULL) ; |
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| 81 | } |
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| 82 | |||
| 83 | Halfedge * |
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| 84 | ELleftbnd(Point * p) |
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| 85 | { |
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| 86 | int i, bucket ; |
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| 87 | Halfedge * he ; |
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| 88 | |||
| 89 | /* Use hash table to get close to desired halfedge */ |
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| 90 | bucket = (p->x - xmin) / deltax * ELhashsize ; |
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| 91 | if (bucket < 0) |
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| 92 | { |
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| 93 | bucket = 0 ; |
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| 94 | } |
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| 95 | if (bucket >= ELhashsize) |
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| 96 | { |
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| 97 | bucket = ELhashsize - 1 ; |
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| 98 | } |
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| 99 | he = ELgethash(bucket) ; |
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| 100 | if (he == (Halfedge *)NULL) |
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| 101 | { |
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| 102 | for (i = 1 ; 1 ; i++) |
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| 103 | { |
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| 104 | if ((he = ELgethash(bucket-i)) != (Halfedge *)NULL) |
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| 105 | { |
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| 106 | break ; |
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| 107 | } |
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| 108 | if ((he = ELgethash(bucket+i)) != (Halfedge *)NULL) |
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| 109 | { |
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| 110 | break ; |
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| 111 | } |
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| 112 | } |
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| 113 | totalsearch += i ; |
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| 114 | } |
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| 115 | ntry++ ; |
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| 116 | /* Now search linear list of halfedges for the corect one */ |
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| 117 | if (he == ELleftend || (he != ELrightend && right_of(he,p))) |
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| 118 | { |
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| 119 | do { |
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| 120 | he = he->ELright ; |
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| 121 | } while (he != ELrightend && right_of(he,p)) ; |
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| 122 | he = he->ELleft ; |
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| 123 | } |
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| 124 | else |
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| 125 | { |
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| 126 | do { |
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| 127 | he = he->ELleft ; |
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| 128 | } while (he != ELleftend && !right_of(he,p)) ; |
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| 129 | } |
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| 130 | /*** Update hash table and reference counts ***/ |
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| 131 | if ((bucket > 0) && (bucket < ELhashsize-1)) |
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| 132 | { |
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| 133 | if (ELhash[bucket] != (Halfedge *)NULL) |
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| 134 | { |
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| 135 | (ELhash[bucket]->ELrefcnt)-- ; |
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| 136 | } |
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| 137 | ELhash[bucket] = he ; |
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| 138 | (ELhash[bucket]->ELrefcnt)++ ; |
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| 139 | } |
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| 140 | return (he) ; |
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| 141 | } |
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| 142 | |||
| 143 | /*** This delete routine can't reclaim node, since pointers from hash |
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| 144 | : table may be present. |
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| 145 | ***/ |
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| 146 | |||
| 147 | void |
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| 148 | ELdelete(Halfedge * he) |
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| 149 | { |
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| 150 | (he->ELleft)->ELright = he->ELright ; |
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| 151 | (he->ELright)->ELleft = he->ELleft ; |
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| 152 | he->ELedge = (Edge *)DELETED ; |
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| 153 | } |
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| 154 | |||
| 155 | Halfedge * |
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| 156 | ELright(Halfedge * he) |
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| 157 | { |
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| 158 | return (he->ELright) ; |
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| 159 | } |
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| 160 | |||
| 161 | Halfedge * |
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| 162 | ELleft(Halfedge * he) |
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| 163 | { |
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| 164 | return (he->ELleft) ; |
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| 165 | } |
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| 166 | |||
| 167 | Site * |
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| 168 | leftreg(Halfedge * he) |
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| 169 | { |
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| 170 | if (he->ELedge == (Edge *)NULL) |
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| 171 | { |
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| 172 | return(bottomsite) ; |
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| 173 | } |
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| 174 | return (he->ELpm == le ? he->ELedge->reg[le] : |
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| 175 | he->ELedge->reg[re]) ; |
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| 176 | } |
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| 177 | |||
| 178 | Site * |
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| 179 | rightreg(Halfedge * he) |
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| 180 | { |
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| 181 | if (he->ELedge == (Edge *)NULL) |
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| 182 | { |
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| 183 | return(bottomsite) ; |
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| 184 | } |
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| 185 | return (he->ELpm == le ? he->ELedge->reg[re] : |
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| 186 | he->ELedge->reg[le]) ; |
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| 187 | } |
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| 188 |