sys/src/cmd/spin/pangen4.h

   1 /***** spin: pangen4.h *****/
   2
   3 /*
   4  * This file is part of the public release of Spin. It is subject to the
   5  * terms in the LICENSE file that is included in this source directory.
   6  * Tool documentation is available at http://spinroot.com
   7  *
   8  * The DFA code below was written by Anuj Puri and Gerard J. Holzmann in
   9  * May 1997, and was inspired by earlier work on data compression using
  10  * sharing tree data structures and graph-encoded sets by J-Ch. Gregoire
  11  * (INRS Telecom, Quebec, Canada) and D.Zampunieris (Univ.Namur, Belgium)
  12  * The splay routine code included here is based on the public domain
  13  * version written by D. Sleator <sleator@cs.cmu.edu> in 1992.
  14  */
  15
  16 static const char *Dfa[] = {
  17         "#ifdef MA",
  18 #if 0
  19         "/*",
  20         "#include <stdio.h>",
  21         "#define uchar  unsigned char",
  22         "*/",
  23         "#define ulong  unsigned long",
  24         "#define ushort unsigned short",
  25         "",
  26 #endif
  27         "#define TWIDTH         256",
  28         "#define HASH(y,n)      (n)*(((long)y))",
  29         "#define INRANGE(e,h)   ((h>=e->From && h<=e->To)||(e->s==1 && e->S==h))",
  30         "",
  31         "extern char    *emalloc(unsigned long);        /* imported routine  */",
  32         "extern void    dfa_init(ushort);       /* 4 exported routines */",
  33         "extern int     dfa_member(ulong);",
  34         "extern int     dfa_store(uchar *);",
  35         "extern void    dfa_stats(void);",
  36         "",
  37         "typedef struct Edge {",
  38         "       uchar From, To;         /* max range 0..255 */",
  39         "       uchar s, S;             /* if s=1, S is singleton */",
  40         "       struct Vertex   *Dst;",
  41         "       struct Edge     *Nxt;",
  42         "} Edge;",
  43         "",
  44         "typedef struct Vertex {",
  45         "       ulong   key, num;       /* key for splay tree, nr incoming edges */",
  46         "       uchar   from[2], to[2]; /* in-node predefined edge info    */",
  47         "       struct  Vertex  *dst[2];/* most nodes have 2 or more edges */",
  48         "       struct  Edge    *Succ;  /* in case there are more edges */",
  49         "       struct  Vertex  *lnk, *left, *right; /* splay tree plumbing */",
  50         "} Vertex;",
  51         "",
  52         "static Edge    *free_edges;",
  53         "static Vertex  *free_vertices;",
  54         "static Vertex  **layers;       /* one splay tree of nodes per layer */",
  55         "static Vertex  **path;         /* run of word in the DFA */",
  56         "static Vertex  *R, *F, *NF;    /* Root, Final, Not-Final */",
  57         "static uchar   *word, *lastword;/* string, and last string inserted */",
  58         "static int     dfa_depth, iv=0, nv=0, pfrst=0, Tally;",
  59         "",
  60         "static void    insert_it(Vertex *, int);       /* splay-tree code */",
  61         "static void    delete_it(Vertex *, int);",
  62         "static Vertex  *find_it(Vertex *, Vertex *, uchar, int);",
  63         "",
  64         "static void",
  65         "recyc_edges(Edge *e)",
  66         "{",
  67         "       if (!e) return;",
  68         "       recyc_edges(e->Nxt);",
  69         "       e->Nxt = free_edges;",
  70         "       free_edges = e;",
  71         "}",
  72         "",
  73         "static Edge *",
  74         "new_edge(Vertex *dst)",
  75         "{      Edge *e;",
  76         "",
  77         "       if (free_edges)",
  78         "       {       e = free_edges;",
  79         "               free_edges = e->Nxt;",
  80         "               e->From = e->To = e->s = e->S = 0;",
  81         "               e->Nxt = (Edge *) 0;",
  82         "       } else",
  83         "               e = (Edge *) emalloc(sizeof(Edge));",
  84         "       e->Dst = dst;",
  85         "",
  86         "       return e;",
  87         "}",
  88         "",
  89         "static void",
  90         "recyc_vertex(Vertex *v)",
  91         "{",
  92         "       recyc_edges(v->Succ);",
  93         "       v->Succ = (Edge *) free_vertices;",
  94         "       free_vertices = v;",
  95         "       nr_states--;",
  96         "}",
  97         "",
  98         "static Vertex *",
  99         "new_vertex(void)",
 100         "{      Vertex *v;",
 101         "",
 102         "       if (free_vertices)",
 103         "       {       v = free_vertices;",
 104         "               free_vertices = (Vertex *) v->Succ;",
 105         "               v->Succ = (Edge *) 0;",
 106         "               v->num  = 0;",
 107         "       } else",
 108         "               v = (Vertex *) emalloc(sizeof(Vertex));",
 109         "",
 110         "       nr_states++;",
 111         "       return v; ",
 112         "}",
 113         "",
 114         "static Vertex *",
 115         "allDelta(Vertex *v, int n)",
 116         "{      Vertex *dst = new_vertex();",
 117         "",
 118         "       v->from[0] = 0;",
 119         "       v->to[0] = 255;",
 120         "       v->dst[0] = dst;",
 121         "       dst->num = 256;",
 122         "       insert_it(v, n);",
 123         "       return dst;",
 124         "}",
 125         "",
 126         "static void",
 127         "insert_edge(Vertex *v, Edge *e)",
 128         "{      /* put new edge first */",
 129         "       if (!v->dst[0])",
 130         "       {       v->dst[0] = e->Dst;",
 131         "               v->from[0] = e->From;",
 132         "               v->to[0] = e->To;",
 133         "               recyc_edges(e);",
 134         "               return;",
 135         "       }",
 136         "       if (!v->dst[1])",
 137         "       {       v->from[1] = v->from[0]; v->from[0] = e->From;",
 138         "               v->to[1]   = v->to[0];   v->to[0]   = e->To;",
 139         "               v->dst[1]  = v->dst[0];  v->dst[0]  = e->Dst;",
 140         "               recyc_edges(e);",
 141         "               return;",
 142         "       } /* shift */",
 143         "       {       int f      = v->from[1];",
 144         "               int t      = v->to[1];",
 145         "               Vertex *d  = v->dst[1];",
 146         "               v->from[1] = v->from[0]; v->from[0] = e->From;",
 147         "               v->to[1]   = v->to[0];   v->to[0]   = e->To;",
 148         "               v->dst[1]  = v->dst[0];  v->dst[0]  = e->Dst;",
 149         "               e->From = f;",
 150         "               e->To   = t;",
 151         "               e->Dst  = d;",
 152         "       }",
 153         "       e->Nxt = v->Succ;",
 154         "       v->Succ = e;",
 155         "}",
 156         "",
 157         "static void",
 158         "copyRecursive(Vertex *v, Edge *e)",
 159         "{      Edge *f;",
 160         "       if (e->Nxt) copyRecursive(v, e->Nxt);",
 161         "       f = new_edge(e->Dst);",
 162         "       f->From = e->From;",
 163         "       f->To   = e->To;",
 164         "       f->s    = e->s;",
 165         "       f->S    = e->S;",
 166         "       f->Nxt  = v->Succ;",
 167         "       v->Succ = f;",
 168         "}",
 169         "",
 170         "static void",
 171         "copyEdges(Vertex *to, Vertex *from)",
 172         "{      int i;",
 173         "       for (i = 0; i < 2; i++)",
 174         "       {       to->from[i] = from->from[i];",
 175         "               to->to[i]   = from->to[i];",
 176         "               to->dst[i]  = from->dst[i];",
 177         "       }",
 178         "       if (from->Succ) copyRecursive(to, from->Succ);",
 179         "}",
 180         "",
 181         "static Edge *",
 182         "cacheDelta(Vertex *v, int h, int first)",
 183         "{      static Edge *ov, tmp;  int i;",
 184         "",
 185         "       if (!first && INRANGE(ov,h))",
 186         "               return ov; /* intercepts about 10%% */",
 187         "       for (i = 0; i < 2; i++)",
 188         "               if (v->dst[i] && h >= v->from[i] && h <= v->to[i])",
 189         "               {       tmp.From = v->from[i];",
 190         "                       tmp.To   = v->to[i];",
 191         "                       tmp.Dst  = v->dst[i];",
 192         "                       tmp.s    =  tmp.S = 0;",
 193         "                       ov = &tmp;",
 194         "                       return ov;",
 195         "               }",
 196         "       for (ov = v->Succ; ov; ov = ov->Nxt)",
 197         "               if (INRANGE(ov,h)) return ov;",
 198         "",
 199         "       Uerror(\"cannot get here, cacheDelta\");",
 200         "       return (Edge *) 0;",
 201         "}",
 202         "",
 203         "static Vertex *",
 204         "Delta(Vertex *v, int h)        /* v->delta[h] */",
 205         "{      Edge *e;",
 206         "",
 207         "       if (v->dst[0] && h >= v->from[0] && h <= v->to[0])",
 208         "               return v->dst[0];       /* oldest edge */",
 209         "       if (v->dst[1] && h >= v->from[1] && h <= v->to[1])",
 210         "               return v->dst[1];",
 211         "       for (e = v->Succ; e; e = e->Nxt)",
 212         "               if (INRANGE(e,h))",
 213         "                       return e->Dst;",
 214         "       Uerror(\"cannot happen Delta\");",
 215         "       return (Vertex *) 0;",
 216         "}",
 217         "",
 218         "static void",
 219         "numDelta(Vertex *v, int d)",
 220         "{      Edge *e;",
 221         "       ulong cnt;",
 222         "       int i;",
 223         "",
 224         "       for (i = 0; i < 2; i++)",
 225         "       if (v->dst[i])",
 226         "       {       cnt = v->dst[i]->num + d*(1 + v->to[i] - v->from[i]);",
 227         "               if (d == 1 && cnt < v->dst[i]->num) goto bad;",
 228         "               v->dst[i]->num = cnt;",
 229         "       }",
 230         "       for (e = v->Succ; e; e = e->Nxt)",
 231         "       {       cnt = e->Dst->num + d*(1 + e->To - e->From + e->s);",
 232         "               if (d == 1 && cnt < e->Dst->num)",
 233         "bad:                   Uerror(\"too many incoming edges\");",
 234         "               e->Dst->num = cnt;",
 235         "       }",
 236         "}",
 237         "",
 238         "static void",
 239         "setDelta(Vertex *v, int h, Vertex *newdst)     /* v->delta[h] = newdst; */",
 240         "{      Edge *e, *f = (Edge *) 0, *g;",
 241         "       int i;",
 242         "",
 243         "       /* remove the old entry, if there */",
 244         "       for (i = 0; i < 2; i++)",
 245         "               if (v->dst[i] && h >= v->from[i] && h <= v->to[i])",
 246         "               {       if (h == v->from[i])",
 247         "                       {       if (h == v->to[i])",
 248         "                               {       v->dst[i] = (Vertex *) 0;",
 249         "                                       v->from[i] = v->to[i] = 0;",
 250         "                               } else",
 251         "                                       v->from[i]++;",
 252         "                       } else if (h == v->to[i])",
 253         "                       {       v->to[i]--;",
 254         "                       } else",
 255         "                       {       g = new_edge(v->dst[i]);/* same dst */",
 256         "                               g->From    = v->from[i];",
 257         "                               g->To      = h-1;       /* left half */",
 258         "                               v->from[i] = h+1;       /* right half */",
 259         "                               insert_edge(v, g);",
 260         "                       }",
 261         "                       goto part2;",
 262         "               }",
 263         "       for (e = v->Succ; e; f = e, e = e->Nxt)",
 264         "       {       if (e->s == 1 && e->S == h)",
 265         "               {       e->s = e->S = 0;",
 266         "                       goto rem_tst;",
 267         "               }",
 268         "               if (h >= e->From && h <= e->To)",
 269         "               {       if (h == e->From)",
 270         "                       {       if (h == e->To)",
 271         "                               {       if (e->s)",
 272         "                                       {       e->From = e->To = e->S;",
 273         "                                               e->s = 0;",
 274         "                                               break;",
 275         "                                       } else",
 276         "                                               goto rem_do;",
 277         "                               } else",
 278         "                                       e->From++;",
 279         "                       } else if (h == e->To)",
 280         "                       {       e->To--;",
 281         "                       } else                          /* split */",
 282         "                       {       g = new_edge(e->Dst);   /* same dst */",
 283         "                               g->From = e->From;",
 284         "                               g->To   = h-1;          /* g=left half */",
 285         "                               e->From = h+1;          /* e=right half */",
 286         "                               g->Nxt  = e->Nxt;       /* insert g */",
 287         "                               e->Nxt  = g;            /* behind e */",
 288         "                               break;                  /* done */",
 289         "                       }",
 290         "",
 291         "rem_tst:               if (e->From > e->To)",
 292         "                       {       if (e->s == 0) {",
 293         "rem_do:                                if (f)",
 294         "                                               f->Nxt = e->Nxt;",
 295         "                                       else",
 296         "                                               v->Succ = e->Nxt;",
 297         "                                       e->Nxt = (Edge *) 0;",
 298         "                                       recyc_edges(e);",
 299         "                               } else",
 300         "                               {       e->From = e->To = e->S;",
 301         "                                       e->s = 0;",
 302         "                       }       }",
 303         "                       break;",
 304         "       }       }",
 305         "part2:",
 306         "       /* check if newdst is already there */",
 307         "       for (i = 0; i < 2; i++)",
 308         "               if (v->dst[i] == newdst)",
 309         "               {       if (h+1 == (int) v->from[i])",
 310         "                       {       v->from[i] = h;",
 311         "                               return;",
 312         "                       }",
 313         "                       if (h == (int) v->to[i]+1)",
 314         "                       {       v->to[i] = h;",
 315         "                               return;",
 316         "               }       }",
 317         "       for (e = v->Succ; e; e = e->Nxt)",
 318         "       {       if (e->Dst == newdst)",
 319         "               {       if (h+1 == (int) e->From)",
 320         "                       {       e->From = h;",
 321         "                               if (e->s == 1 && e->S+1 == e->From)",
 322         "                               {       e->From = e->S;",
 323         "                                       e->s = e->S = 0;",
 324         "                               }",
 325         "                               return;",
 326         "                       }",
 327         "                       if (h == (int) e->To+1)",
 328         "                       {       e->To = h;",
 329         "                               if (e->s == 1 && e->S == e->To+1)",
 330         "                               {       e->To = e->S;",
 331         "                                       e->s = e->S = 0;",
 332         "                               }",
 333         "                               return;",
 334         "                       }",
 335         "                       if (e->s == 0)",
 336         "                       {       e->s = 1;",
 337         "                               e->S = h;",
 338         "                               return;",
 339         "       }       }       }",
 340         "       /* add as a new edge */",
 341         "       e = new_edge(newdst);",
 342         "       e->From = e->To = h;",
 343         "       insert_edge(v, e);",
 344         "}",
 345         "",
 346         "static ulong",
 347         "cheap_key(Vertex *v)",
 348         "{      ulong vk2 = 0;",
 349         "",
 350         "       if (v->dst[0])",
 351         "       {       vk2 = (ulong) v->dst[0];",
 352         "               if ((ulong) v->dst[1] > vk2)",
 353         "                       vk2 = (ulong) v->dst[1];",
 354         "       } else if (v->dst[1])",
 355         "               vk2 = (ulong) v->dst[1]; ",
 356         "       if (v->Succ)",
 357         "       {       Edge *e;",
 358         "               for (e = v->Succ; e; e = e->Nxt)",
 359         "                       if ((ulong) e->Dst > vk2)",
 360         "                               vk2 = (ulong) e->Dst;",
 361         "       }",
 362         "       Tally = (vk2>>2)&(TWIDTH-1);",
 363         "       return v->key;",
 364         "}",
 365         "",
 366         "static ulong",
 367         "mk_key(Vertex *v)      /* not sensitive to order */",
 368         "{      ulong m = 0, vk2 = 0;",
 369         "       Edge *e;",
 370         "",
 371         "       if (v->dst[0])",
 372         "       {       m += HASH(v->dst[0], v->to[0] - v->from[0] + 1);",
 373         "               vk2 = (ulong) v->dst[0]; ",
 374         "       }",
 375         "       if (v->dst[1])",
 376         "       {       m += HASH(v->dst[1], v->to[1] - v->from[1] + 1);",
 377         "               if ((ulong) v->dst[1] > vk2) vk2 = (ulong) v->dst[1]; ",
 378         "       }",
 379         "       for (e = v->Succ; e; e = e->Nxt)",
 380         "       {       m += HASH(e->Dst, e->To - e->From + 1 + e->s);",
 381         "               if ((ulong) e->Dst > vk2) vk2 = (ulong) e->Dst; ",
 382         "       }",
 383         "       Tally = (vk2>>2)&(TWIDTH-1);",
 384         "       return m;",
 385         "}",
 386         "",
 387         "static ulong",
 388         "mk_special(int sigma, Vertex *n, Vertex *v)",
 389         "{      ulong m = 0, vk2 = 0;",
 390         "       Edge *f;",
 391         "       int i;",
 392         "",
 393         "       for (i = 0; i < 2; i++)",
 394         "               if (v->dst[i])",
 395         "               {       if (sigma >= v->from[i] && sigma <= v->to[i])",
 396         "                       {       m += HASH(v->dst[i], v->to[i]-v->from[i]);",
 397         "                               if ((ulong) v->dst[i] > vk2",
 398         "                               &&   v->to[i] > v->from[i])",
 399         "                                       vk2 = (ulong) v->dst[i]; ",
 400         "                       } else",
 401         "                       {       m += HASH(v->dst[i], v->to[i]-v->from[i]+1);",
 402         "                               if ((ulong) v->dst[i] > vk2)",
 403         "                                       vk2 = (ulong) v->dst[i]; ",
 404         "               }       }",
 405         "       for (f = v->Succ; f; f = f->Nxt)",
 406         "       {       if (sigma >= f->From && sigma <= f->To)",
 407         "               {       m += HASH(f->Dst, f->To - f->From + f->s);",
 408         "                       if ((ulong) f->Dst > vk2",
 409         "                       &&   f->To - f->From + f->s > 0)",
 410         "                               vk2 = (ulong) f->Dst; ",
 411         "               } else if (f->s == 1 && sigma == f->S)",
 412         "               {       m += HASH(f->Dst, f->To - f->From + 1);",
 413         "                       if ((ulong) f->Dst > vk2) vk2 = (ulong) f->Dst; ",
 414         "               } else",
 415         "               {       m += HASH(f->Dst, f->To - f->From + 1 + f->s);",
 416         "                       if ((ulong) f->Dst > vk2) vk2 = (ulong) f->Dst; ",
 417         "       }       }",
 418         "",
 419         "       if ((ulong) n > vk2) vk2 = (ulong) n; ",
 420         "       Tally = (vk2>>2)&(TWIDTH-1);",
 421         "       m += HASH(n, 1);",
 422         "       return m;",
 423         "}",
 424         "",
 425         "void ",
 426         "dfa_init(ushort nr_layers)",
 427         "{      int i; Vertex *r, *t;",
 428         "",
 429         "       dfa_depth = nr_layers;  /* one byte per layer */",
 430         "       path   = (Vertex **) emalloc((dfa_depth+1)*sizeof(Vertex *));",
 431         "       layers = (Vertex **) emalloc(TWIDTH*(dfa_depth+1)*sizeof(Vertex *));",
 432         "       lastword = (uchar *) emalloc((dfa_depth+1)*sizeof(uchar));",
 433         "       lastword[dfa_depth] = lastword[0] = 255;",
 434         "       path[0] = R = new_vertex(); F = new_vertex();",
 435         "",
 436         "       for (i = 1, r = R; i < dfa_depth; i++, r = t)",
 437         "               t = allDelta(r, i-1);",
 438         "       NF = allDelta(r, i-1);",
 439         "}",
 440         "",
 441         "#if 0",
 442         "static void complement_dfa(void) { Vertex *tmp = F; F = NF; NF = tmp; }",
 443         "#endif",
 444         "",
 445         "double",
 446         "tree_stats(Vertex *t)",
 447         "{      Edge *e; double cnt=0.0;",
 448         "       if (!t) return 0;",
 449         "       if (!t->key) return 0;",
 450         "       t->key = 0; /* precaution */",
 451         "       if (t->dst[0]) cnt++;",
 452         "       if (t->dst[1]) cnt++;",
 453         "       for (e = t->Succ; e; e = e->Nxt)",
 454         "               cnt++;",
 455         "       cnt += tree_stats(t->lnk);",
 456         "       cnt += tree_stats(t->left);",
 457         "       cnt += tree_stats(t->right);",
 458         "       return cnt;",
 459         "}",
 460         "",
 461         "void",
 462         "dfa_stats(void)",
 463         "{      int i, j; double cnt = 0.0;",
 464         "       for (j = 0; j < TWIDTH; j++)",
 465         "       for (i = 0; i < dfa_depth+1; i++)",
 466         "               cnt += tree_stats(layers[i*TWIDTH+j]);",
 467         "       printf(\"Minimized Automaton:\t%%6lu nodes and %%6g edges\\n\",",
 468         "               nr_states, cnt);",
 469         "}",
 470         "",
 471         "int",
 472         "dfa_member(ulong n)",
 473         "{      Vertex **p, **q;",
 474         "       uchar *w = &word[n];",
 475         "       int i;",
 476         "",
 477         "       p = &path[n]; q = (p+1);",
 478         "       for (i = n; i < dfa_depth; i++)",
 479         "               *q++ = Delta(*p++, *w++);",
 480         "       return (*p == F);",
 481         "}",
 482         "",
 483         "int",
 484         "dfa_store(uchar *sv)",
 485         "{      Vertex **p, **q, *s, *y, *old, *new = F;",
 486         "       uchar *w, *u = lastword;",
 487         "       int i, j, k;",
 488         "",
 489         "       w = word = sv;",
 490         "       while (*w++ == *u++)    /* find first byte that differs */",
 491         "               ;",
 492         "       pfrst = (int) (u - lastword) - 1;",
 493         "       memcpy(&lastword[pfrst], &sv[pfrst], dfa_depth-pfrst);",
 494         "       if (pfrst > iv) pfrst = iv;",
 495         "       if (pfrst > nv) pfrst = nv;",
 496         "/* phase1: */",
 497         "       p = &path[pfrst]; q = (p+1); w = &word[pfrst];",
 498         "       for (i = pfrst; i < dfa_depth; i++)",
 499         "               *q++ = Delta(*p++, *w++);       /* (*p)->delta[*w++]; */",
 500         "",
 501         "       if (*p == F) return 1;  /* it's already there */",
 502         "/* phase2: */",
 503         "       iv = dfa_depth;",
 504         "       do {    iv--;",
 505         "               old = new;",
 506         "               new = find_it(path[iv], old, word[iv], iv);",
 507         "       } while (new && iv > 0);",
 508         "",
 509         "/* phase3: */",
 510         "       nv = k = 0; s = path[0];",
 511         "       for (j = 1; j <= iv; ++j) ",
 512         "               if (path[j]->num > 1)",
 513         "               {       y = new_vertex();",
 514         "                       copyEdges(y, path[j]);",
 515         "                       insert_it(y, j);",
 516         "                       numDelta(y, 1);",
 517         "                       delete_it(s, j-1);",
 518         "                       setDelta(s, word[j-1], y);",
 519         "                       insert_it(s, j-1);",
 520         "                       y->num = 1;     /* initial value 1 */",
 521         "                       s = y;",
 522         "                       path[j]->num--; /* only 1 moved from j to y */",
 523         "                       k = 1;",
 524         "               } else",
 525         "               {       s = path[j];",
 526         "                       if (!k) nv = j;",
 527         "               }",
 528         "       y = Delta(s, word[iv]);",
 529         "       y->num--;",
 530         "       delete_it(s, iv); ",
 531         "       setDelta(s, word[iv], old);",
 532         "       insert_it(s, iv); ",
 533         "       old->num++;",
 534         "",
 535         "       for (j = iv+1; j < dfa_depth; j++)",
 536         "               if (path[j]->num == 0)",
 537         "               {       numDelta(path[j], -1);",
 538         "                       delete_it(path[j], j);",
 539         "                       recyc_vertex(path[j]);",
 540         "               } else",
 541         "                       break;",
 542         "       return 0;",
 543         "}",
 544         "",
 545         "static Vertex *",
 546         "splay(ulong i, Vertex *t)",
 547         "{      Vertex N, *l, *r, *y;",
 548         "",
 549         "       if (!t) return t;",
 550         "       N.left = N.right = (Vertex *) 0;",
 551         "       l = r = &N;",
 552         "       for (;;)",
 553         "       {       if (i < t->key)",
 554         "               {       if (!t->left) break;",
 555         "                       if (i < t->left->key)",
 556         "                       {       y = t->left;",
 557         "                               t->left = y->right;",
 558         "                               y->right = t;",
 559         "                               t = y;",
 560         "                               if (!t->left) break;",
 561         "                       }",
 562         "                       r->left = t;",
 563         "                       r = t;",
 564         "                       t = t->left;",
 565         "               } else if (i > t->key)",
 566         "               {       if (!t->right) break;",
 567         "                       if (i > t->right->key)",
 568         "                       {       y = t->right;",
 569         "                               t->right = y->left;",
 570         "                               y->left = t;",
 571         "                               t = y;",
 572         "                               if (!t->right) break;",
 573         "                       }",
 574         "                       l->right = t;",
 575         "                       l = t;",
 576         "                       t = t->right;",
 577         "               } else",
 578         "                       break;",
 579         "       }",
 580         "       l->right = t->left;",
 581         "       r->left = t->right;",
 582         "       t->left = N.right;",
 583         "       t->right = N.left;",
 584         "       return t;",
 585         "}",
 586         "",
 587         "static void",
 588         "insert_it(Vertex *v, int L)",
 589         "{      Vertex *new, *t;",
 590         "       ulong i; int nr;",
 591         "",
 592         "       i = mk_key(v);",
 593         "       nr = ((L*TWIDTH)+Tally);",
 594         "       t = layers[nr];",
 595         "",
 596         "       v->key = i; ",
 597         "       if (!t)",
 598         "       {       layers[nr] = v;",
 599         "               return;",
 600         "       }",
 601         "       t = splay(i, t);",
 602         "       if (i < t->key)",
 603         "       {       new = v;",
 604         "               new->left = t->left;",
 605         "               new->right = t;",
 606         "               t->left = (Vertex *) 0;",
 607         "       } else if (i > t->key)",
 608         "       {       new = v;",
 609         "               new->right = t->right;",
 610         "               new->left = t;",
 611         "               t->right = (Vertex *) 0;",
 612         "       } else   /* it's already there */",
 613         "       {       v->lnk = t->lnk; /* put in linked list off v */",
 614         "               t->lnk = v;",
 615         "               new = t;",
 616         "       }",
 617         "       layers[nr] = new;",
 618         "}",
 619         "",
 620         "static int",
 621         "checkit(Vertex *h, Vertex *v, Vertex *n, uchar sigma)",
 622         "{      Edge *g, *f;",
 623         "       int i, k, j = 1;",
 624         "",
 625         "       for (k = 0; k < 2; k++)",
 626         "               if (h->dst[k])",
 627         "               {       if (sigma >= h->from[k] && sigma <= h->to[k])",
 628         "                       {       if (h->dst[k] != n) goto no_match;",
 629         "                       }",
 630         "                       for (i = h->from[k]; i <= h->to[k]; i++)",
 631         "                       {       if (i == sigma) continue;",
 632         "                               g = cacheDelta(v, i, j); j = 0;",
 633         "                               if (h->dst[k] != g->Dst)",
 634         "                                       goto no_match;",
 635         "                               if (g->s == 0 || g->S != i)",
 636         "                                       i = g->To;",
 637         "               }       }",
 638         "       for (f = h->Succ; f; f = f->Nxt)",
 639         "       {       if (INRANGE(f,sigma))",
 640         "               {       if (f->Dst != n) goto no_match;",
 641         "               }",
 642         "               for (i = f->From; i <= f->To; i++)",
 643         "               {       if (i == sigma) continue;",
 644         "                       g = cacheDelta(v, i, j); j = 0;",
 645         "                       if (f->Dst != g->Dst)",
 646         "                               goto no_match;",
 647         "                       if (g->s == 1 && i == g->S)",
 648         "                               continue;",
 649         "                       i = g->To;",
 650         "               }",
 651         "               if (f->s && f->S != sigma)",
 652         "               {       g = cacheDelta(v, f->S, 1);",
 653         "                       if (f->Dst != g->Dst)",
 654         "                               goto no_match;",
 655         "               }",
 656         "       }",
 657         "       if (h->Succ || h->dst[0] || h->dst[1]) return 1;",
 658         "no_match:",
 659         "       return 0;",
 660         "}",
 661         "",
 662         "static Vertex *",
 663         "find_it(Vertex *v, Vertex *n, uchar sigma, int L)",
 664         "{      Vertex *z, *t;",
 665         "       ulong i; int nr;",
 666         "",
 667         "       i = mk_special(sigma,n,v);",
 668         "       nr = ((L*TWIDTH)+Tally);",
 669         "       t = layers[nr];",
 670         "",
 671         "       if (!t) return (Vertex *) 0;",
 672         "       layers[nr] = t = splay(i, t);",
 673         "       if (i == t->key)",
 674         "       for (z = t; z; z = z->lnk)",
 675         "               if (checkit(z, v, n, sigma))",
 676         "                       return z;",
 677         "",
 678         "       return (Vertex *) 0;",
 679         "}",
 680         "",
 681         "static void",
 682         "delete_it(Vertex *v, int L)",
 683         "{      Vertex *x, *t;",
 684         "       ulong i; int nr;",
 685         "",
 686         "       i = cheap_key(v);",
 687         "       nr = ((L*TWIDTH)+Tally);",
 688         "       t = layers[nr];",
 689         "       if (!t) return;",
 690         "",
 691         "       t = splay(i, t);",
 692         "       if (i == t->key)",
 693         "       {       Vertex *z, *y = (Vertex *) 0;",
 694         "               for (z = t; z && z != v; y = z, z = z->lnk)",
 695         "                       ;",
 696         "               if (z != v) goto bad;",
 697         "               if (y)",
 698         "               {       y->lnk = z->lnk;",
 699         "                       z->lnk = (Vertex *) 0;",
 700         "                       layers[nr] = t;",
 701         "                       return;",
 702         "               } else if (z->lnk)      /* z == t == v */",
 703         "               {       y = z->lnk;",
 704         "                       y->left = t->left;",
 705         "                       y->right = t->right;",
 706         "                       t->left = t->right = t->lnk = (Vertex *) 0;",
 707         "                       layers[nr] = y;",
 708         "                       return;",
 709         "               }",
 710         "               /* delete the node itself */",
 711         "               if (!t->left)",
 712         "               {       x = t->right;",
 713         "               } else",
 714         "               {       x = splay(i, t->left);",
 715         "                       x->right = t->right;",
 716         "               }",
 717         "               t->left = t->right = t->lnk = (Vertex *) 0;",
 718         "               layers[nr] = x;",
 719         "               return;",
 720         "       }",
 721         "bad:   Uerror(\"cannot happen delete\");",
 722         "}",
 723         "#endif", /* MA */
 724         0,
 725 };