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/****************************************************************/
/* EusLisp: intern.c
/* intern a symbol in a package
/* Copyright (c) 1989, Toshihiro MATSUI, Electrotechnical Laboratory
/*
/****************************************************************/
static char *rcsid="@(#)$Id$";
#include "eus.h"
int export_all;
int rehash(str)
register pointer str; /*string object*/
{ register int i,l,hash;
register byte *id;
id=str->c.str.chars;
l=vecsize(str);
hash=l;
for (i=0; i<l; i++) hash+=(hash<<2)+id[i];
return(hash & 0x1fffffff);}
pointer findsymbol(id,l,symvec,hashval)
byte *id;
int l,*hashval;
register pointer symvec;
{ register pointer sym,pnam;
register int i,size,hash=l,flag=0;
for (i=0; i<l; i++) hash+=(hash<<2)+id[i];
hash&=0x1fffffff;
size=vecsize(symvec);
if (size==0) return(NULL);
hash=hash % size;
do {
sym = symvec->c.vec.v[hash];
if (issymbol(sym)) {
pnam=sym->c.sym.pname;
if (strlength(pnam)==l &&
!memcmp((char *)pnam->c.str.chars, (char *)id, l)) {
*hashval=hash; return(sym);}}
if (sym==makeint(0)) {
if (flag==0) *hashval=hash;
return(NULL);}
if (sym==makeint(1) && flag==0) { flag=1; *hashval=hash;}
if (++hash>=size) hash=0;}
while (1);}
static pointer extendsymvec(symvec)
pointer symvec;
{ register pointer newsymvec,sym;
bpointer bp;
register int i,newsize,size,hash;
size=vecsize(symvec);
bp=bpointerof(symvec);
#ifdef RGC
newsize=buddysize[(bp->h.bix & TAGMASK)+1]-2;
#else
newsize=buddysize[bp->h.bix+1]-2;
#endif
newsymvec=makevector(C_VECTOR,newsize);
for (i=0; i<newsize; i++) newsymvec->c.vec.v[i]=makeint(0); /*empty mark*/
for (i=0; i<size; i++) { /*rehash all symbols*/
sym=symvec->c.vec.v[i];
if (issymbol(sym)) {
hash=rehash(sym->c.sym.pname) % newsize;
while (newsymvec->c.vec.v[hash]!=makeint(0)) { /*find an empty slot*/
if (++hash>=newsize) hash=0;}
pointer_update(newsymvec->c.vec.v[hash],sym);}}
#ifdef SAFETY
take_care(newsymvec);
#endif
return(newsymvec);}
pointer export(sym,pkg)
pointer sym,pkg;
{ register pointer symvec=pkg->c.pkg.symvector; /*external symbol table*/
register int size, newsymcount;
int hash;
pointer usedby,usedbylist=pkg->c.pkg.used_by;
pointer pnam,s;
pnam=sym->c.sym.pname;
usedby = (T);
/*check symbol conflict in each of used-by packages*/
while (usedby && iscons(usedbylist)) {
usedby=ccar(usedbylist);
usedbylist=ccdr(usedbylist);
s=findsymbol(pnam->c.str.chars, strlength(pnam),
usedby->c.pkg.intsymvector, &hash);
if (s && s!=sym) error(E_SYMBOLCONFLICT,sym);}
size=vecsize(symvec);
hash=rehash(pnam) % size;
while (1) {
if (symvec->c.vec.v[hash]==sym) return(sym);
if (isint(symvec->c.vec.v[hash])) {
pointer_update(symvec->c.vec.v[hash],sym);
newsymcount=intval(pkg->c.pkg.symcount)+1;
pkg->c.pkg.symcount=makeint(newsymcount);
if (newsymcount > (size / 2))
pointer_update(pkg->c.pkg.symvector, extendsymvec(symvec));
return(sym);}
else if (++hash>=size) hash=0;}
}
pointer intern(ctx,id,l,pkg)
register context *ctx;
char *id; /*pointer to a string*/
int l; /*l=strlen(id)*/
pointer pkg; /*destination package*/
{ register pointer sym,symvec,newsym,uselist,use;
register int i,size;
int hash,newhash;
if ((sym=findsymbol((byte *)id,l,pkg->c.pkg.intsymvector,&hash))) return(sym);
uselist=pkg->c.pkg.use;
while (islist(uselist)) { /*search in external symbols in inherited packages*/
use=ccar(uselist);
uselist=ccdr(uselist);
if ((sym=findsymbol((byte *)id,l,use->c.pkg.symvector,&newhash))) return(sym);}
/*create the symbol and insert it in the package*/
symvec=pkg->c.pkg.intsymvector;
size=vecsize(symvec);
newsym=makesymbol(ctx,id,l,pkg);
/*put it in the package*/
while (issymbol(symvec->c.vec.v[hash])) if (++hash>=size) hash=0;
pointer_update(symvec->c.vec.v[hash],newsym);
if (pkg==keywordpkg) {
newsym->c.sym.vtype=V_CONSTANT;
pointer_update(newsym->c.sym.speval,newsym);
export(newsym,pkg);}
l=intval(pkg->c.pkg.intsymcount)+1;
pkg->c.pkg.intsymcount=makeint(l);
if (l>(size/2)) { /*extend hash table*/
vpush(newsym);
pointer_update(pkg->c.pkg.intsymvector,extendsymvec(symvec));
vpop();}
/* export all the symbols to avoid incompatibility with old EusLisp*/
if (export_all) export(newsym, pkg);
#ifdef SAFETY
take_care(newsym);
#endif
return(newsym); }
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