UNIX 6th Ed. - /usr/source/sno/sno3.c

   1: #include "sno.h"
   2: 
   3: /*
   4:  * sno3
   5:  */
   6: 
   7: 
   8: bextend(str, last)
   9: struct node *str, *last;
  10: {
  11:     register struct node *a, *s;
  12:     register int b;
  13:     int c, d;
  14: 
  15:     s = str;
  16:     if ((c = s->p1) == 0)
  17:         goto bad;
  18:     b = d = 0;
  19:     a = s->p2;
  20:     if(a == 0) {
  21:         a = c;
  22:         goto eb2;
  23:     }
  24: eb1:
  25:     if (a == last)
  26:         goto bad;
  27:     a = a->p1;
  28: eb2:
  29:     d++;
  30:     c = class(a->ch);
  31:     if (c == 1) { /* rp */
  32:         if (b == 0)
  33:             goto bad;
  34:         b--;
  35:         goto eb3;
  36:     }
  37:     if (c == 2) { /* lp */
  38:         b++;
  39:         goto eb1;
  40:     }
  41: eb3:
  42:     if (b == 0) {
  43:         s->p2= a;
  44:         return(d);
  45:     }
  46:     goto eb1;
  47: bad:
  48:     return(0);
  49: }
  50: 
  51: ubextend(str, last)
  52: struct node *str, *last;
  53: {
  54:     register struct node *a, *b, *s;
  55: 
  56:     s = str;
  57:     a = s->p1;
  58:     if(a == 0)
  59:         goto bad;
  60:     b = s->p2;
  61:     if(b == 0)
  62:         goto good;
  63:     if (b == last)
  64:         goto bad;
  65:     a = b->p1;
  66: good:
  67:     s->p2 = a;
  68:     return(1);
  69: bad:
  70:     return(0);
  71: }
  72: 
  73: search(arg, r)
  74: struct node *arg, *r;
  75: {
  76:     struct node *list, *back, *str,
  77:         *etc, *next, *last, *base, *e;
  78:     register struct node *a, *b, *var;
  79:     int c, d;
  80: 
  81:     a = arg->p2;
  82:     list = base = alloc();
  83:     last = next = 0;
  84:     goto badv1;
  85: badvanc:
  86:     a = a->p1;
  87:     if (a->typ == 0) {
  88:         list->p1 = 0;
  89:         if (rfail == 1) {
  90:             a = 0;
  91:             goto fail;
  92:         }
  93:         list = base;
  94:         if (r == 0)
  95:             next = last = 0; else {
  96:             next = r->p1;
  97:             last = r->p2;
  98:         }
  99:         goto adv1;
 100:     }
 101:     b = alloc();
 102:     list->p1 = b;
 103:     list = b;
 104: badv1:
 105:     list->p2 = back = alloc();
 106:     back->p1 = last;
 107:     b = a->p2;
 108:     c = a->typ;
 109:     list->typ = c;
 110:     if (c < 2) {
 111:         back->p2 = eval(b, 1);
 112:         goto badvanc;
 113:     }
 114:     last = list;
 115:     str = alloc();
 116:     etc = alloc();
 117:     back->p2 = var = alloc();
 118:     var->typ = b->typ;
 119:     var->p1 = str;
 120:     var->p2 = etc;
 121:     e = b->p1;
 122:     if (e == 0)
 123:         etc->p1 = 0; else
 124:         etc->p1 = eval(e, 0);
 125:     e = b->p2;
 126:     if (e == 0)
 127:         etc->p2 = 0; else {
 128:         e = eval(e, 1);
 129:         etc->p2 = strbin(e);
 130:         delete(e);
 131:     }
 132:     goto badvanc;
 133: 
 134: retard:
 135:     a = back->p1;
 136:     if (a == 0) {
 137:         rfail = 1;
 138:         goto fail;
 139:     }
 140:     list = a;
 141:     back = list->p2;
 142:     var = back->p2;
 143:     str = var->p1;
 144:     etc = var->p2;
 145:     if (etc->p2)
 146:         goto retard;
 147:     if (var->typ == 1) {
 148:         if (bextend(str, last) == 0)
 149:             goto retard;
 150:         goto adv0;
 151:     }
 152:     if (ubextend(str, last) == 0)
 153:         goto retard;
 154: adv0:
 155:     a = str->p2;
 156: adv01:
 157:     if (a == last)
 158:         next = 0; else
 159:         next = a->p1;
 160: advanc:
 161:     a = list->p1;
 162:     if (a == 0) {
 163:         a = alloc();
 164:         if (r == 0) {
 165:             a->p1 = a->p2 = 0;
 166:             goto fail;
 167:         }
 168:         b = r->p1;
 169:         a->p1 = b;
 170:         if (next == 0) {
 171:             a->p2 = r->p2;
 172:             goto fail;
 173:         }
 174:         while(1) {
 175:             e = b->p1;
 176:             if (e == next) {
 177:                 a->p2 = b;
 178:                 goto fail;
 179:             }
 180:             b = e;
 181:         }
 182:     }
 183:     list = a;
 184: adv1:
 185:     back = list->p2;
 186:     var = back->p2;
 187:     d = list->typ;
 188:     if(d < 2) {
 189:         if (var == 0)
 190:             goto advanc;
 191:         if (next == 0)
 192:             goto retard;
 193:         a = next;
 194:         b = var->p1;
 195:         e = var->p2;
 196:         while(1) {
 197:             if (a->ch != b->ch)
 198:                 goto retard;
 199:             if (b == e)
 200:                 goto adv01;
 201:             if (a == last)
 202:                 goto retard;
 203:             a = a->p1;
 204:             b = b->p1;
 205:         }
 206:     }
 207:     str = var->p1;
 208:     etc = var->p2;
 209:     str->p1 = next;
 210:     str->p2 = 0;
 211:     c = etc->p2;
 212:     if (var->typ == 1) {
 213:         d = bextend(str, last);
 214:         if (d == 0)
 215:             goto retard;
 216:         if (c == 0)
 217:             goto adv0;
 218:         while(1) {
 219:             c =- d;
 220:             if (c == 0)
 221:                 goto adv0;
 222:             if (c < 0)
 223:                 goto retard;
 224:             d = bextend(str, last);
 225:             if (d == 0)
 226:                 goto retard;
 227:         }
 228:     }
 229:     if (c == 0) {
 230:         if(d==3 & next!=0) {
 231:             str->p2 = last;
 232:             goto adv0;
 233:         }
 234:         goto advanc;
 235:     }
 236:     while(c--)
 237:         if (ubextend(str, last) == 0)
 238:             goto retard;
 239:     goto adv0;
 240: 
 241: fail:
 242:     list = base;
 243:     goto f1;
 244: fadv:
 245:     free(back);
 246:     b = list->p1;
 247:     free(list);
 248:     if (b == 0)
 249:         return(a);
 250:     list = b;
 251: f1:
 252:     back = list->p2;
 253:     var = back->p2;
 254:     if (list->typ < 2) {
 255:         delete(var);
 256:         goto fadv;
 257:     }
 258:     str = var->p1;
 259:     etc = var->p2;
 260:     if (a != 0 & etc->p1 != 0) {
 261:         if (str->p2 == 0) {
 262:             free(str);
 263:             str = 0;
 264:         }
 265:         assign(etc->p1, copy(str));
 266:     }
 267:     if (str)
 268:         free(str);
 269:     free(etc);
 270:     free(var);
 271:     goto fadv;
 272: }

Defined functions