69 lines
1.3 KiB
C
69 lines
1.3 KiB
C
/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*/
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#ifndef NORCSID
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static char rcsid[]= "$Header$";
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#endif
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#include "assert.h"
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#include "param.h"
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#include "lookup.h"
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char *myalloc();
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char *mystrcpy();
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symbol dumsym; /* dummy to return in case of error */
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symbol *lookup(name,type,style)
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char *name;
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symtype type;
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lookupstyle style;
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{
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symbol *sy_p,**sy_pp;
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for (sy_pp = &symhash[hashvalue(name)];(sy_p= *sy_pp) != 0;sy_pp= &sy_p->sy_next) {
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if (strcmp(sy_p->sy_name,name)!=0)
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continue;
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switch(style) {
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default:
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assert(0);
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case justlooking:
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case mustexist:
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case makeexist:
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if (type==symany || type==sy_p->sy_type)
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return(sy_p);
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continue;
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case newsymbol:
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error("%s already defined",name);
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return(&dumsym);
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}
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}
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switch(style) {
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default:
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assert(0);
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case justlooking:
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return((symbol *) 0);
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case mustexist:
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fatal("%s is unknown symbol",name);
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/* NOTREACHED */
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case newsymbol:
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case makeexist:
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NEW(sy_p,symbol);
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sy_p->sy_next = 0;
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sy_p->sy_name = mystrcpy(name);
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assert(type!=symany);
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sy_p->sy_type = type;
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*sy_pp = sy_p;
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return(sy_p);
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}
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}
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hashvalue(s) register char *s; {
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register unsigned sum=0;
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register i;
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for(i=0;*s;s++,i=(i+3)&07)
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sum += *s<<i;
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return(sum%NSYMHASH);
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}
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