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[unix-history] / .ref-Research-V6 / usr / source / m6 / m63.c

#

#include "m6.h"

char *
finddef(n) {
       char *p;
       if((p = lookup(arg(n)))==0)
               if((p = lookup(""))==0) diag("Software error");
       return(p); 
}

char *
lookup(s) {
       char *dt;
       dt = df;
       while(dt>d0) {
               if(dt->dswitch>=0 && comp(s,&dt->dident)) return(dt);
               dt =+ dt->prev; 
       }
       return(0); 
}

comp(s,t) 
char *s, *t; 
{
       for(;*s++ == *t;t++)
               if(*t==0) return(1);
       return(0); 
}

remove(n) {
       char *p;
       if(p = lookup(arg(n))) if(p>d0+2) {
               trashflag++;
               p->dswitch = -1; 
       } 
}

trash() {
       char *p,*q,*r;
       if(lg>0) return;
       while(df->dswitch<0) {
               de = df;
               df =+ df->prev;
               trashflag--; 
       }
       if(trashflag<=0) return;
       de = (de+1)&0177776;
       revptr(de,df,&p,&q);
       q = p;
       for(;p->word!=0;p=+r->word) {
               r = p;
               if(p->dswitch>=0) {
                       r = q;
                       q = move(p,q,p->word); 
               } 
       }
       q->word = 0;
       revptr(d0,d0+2,&df,&de); 
}


revptr(p,q,np,nq) 
char *p, *q, **np, **nq;
{
       int t;
       p->word = 0;
       while((t = q->word)!=0) {
               q->word = p-q; 
               p = q; 
               q =+ t;
               if(q<d0 || q>dmax) diag("Software error"); 
       }
       *np = p;
       *nq = q; 
}

char *
move(from,to,count) 
char *from, *to;
{
       while(count-->0) *to++ = *from++;
       return(to); 
}