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Annotation of 41BSD/cmd/pi/lookup.c, revision 1.1.1.1

1.1       root        1: /* Copyright (c) 1979 Regents of the University of California */
                      2: 
                      3: static char sccsid[] = "@(#)lookup.c 1.1 8/27/80";
                      4: 
                      5: #include "whoami.h"
                      6: #include "0.h"
                      7: 
                      8: /*
                      9:  * Lookup is called to
                     10:  * find a symbol in the
                     11:  * block structure symbol
                     12:  * table and returns a pointer to
                     13:  * its namelist entry.
                     14:  */
                     15: struct nl *
                     16: lookup(s)
                     17:        register char *s;
                     18: {
                     19:        register struct nl *p;
                     20:        register struct udinfo *udp;
                     21: 
                     22:        if (s == NIL) {
                     23:                nocascade();
                     24:                return (NIL);
                     25:        }
                     26:        p = lookup1(s);
                     27:        if (p == NIL) {
                     28:                derror("%s is undefined", s);
                     29:                return (NIL);
                     30:        }
                     31:        if (p->class == FVAR) {
                     32:                p = p->chain;
                     33:                bn--;
                     34:        }
                     35:        return (p);
                     36: }
                     37: 
                     38: #ifndef PI0
                     39: int    flagwas;
                     40: #endif
                     41: /*
                     42:  * Lookup1 is an internal lookup.
                     43:  * It is not an error to call lookup1
                     44:  * if the symbol is not defined.  Also
                     45:  * lookup1 will return FVARs while
                     46:  * lookup never will, thus asgnop
                     47:  * calls it when it thinks you are
                     48:  * assigning to the function variable.
                     49:  */
                     50: 
                     51: struct nl *
                     52: lookup1(s)
                     53:        register char *s;
                     54: {
                     55:        register struct nl *p;
                     56: #ifndef PI0
                     57:        register struct nl *q;
                     58: #endif
                     59:        register int i;
                     60: 
                     61:        if (s == NIL)
                     62:                return (NIL);
                     63:        bn = cbn;
                     64: #ifndef PI0
                     65:        /*
                     66:         * We first check the field names
                     67:         * of the currently active with
                     68:         * statements (expensive since they
                     69:         * are not hashed).
                     70:         */
                     71:        for (p = withlist; p != NIL; p = p->nl_next) {
                     72:                q = p->type;
                     73:                if (q == NIL)
                     74:                        continue;
                     75:                if (reclook(q, s) != NIL)
                     76:                        /*
                     77:                         * Return the WITHPTR, lvalue understands.
                     78:                         */
                     79:                        return (p);
                     80:        }
                     81: #endif
                     82:        /*
                     83:         * Symbol table is a 64 way hash
                     84:         * on the low bits of the character
                     85:         * pointer value. (Simple, but effective)
                     86:         */
                     87:        i = (int) s & 077;
                     88:        for (p = disptab[i]; p != NIL; p = p->nl_next)
                     89:                if (p->symbol == s && p->class != FIELD && p->class != BADUSE) {
                     90:                        bn = (p->nl_block & 037);
                     91: #ifndef PI0
                     92:                        flagwas = p->nl_flags;
                     93:                        p->nl_flags |= NUSED;
                     94: #endif
                     95:                        return (p);
                     96:                }
                     97:        return (NIL);
                     98: }
                     99: 
                    100: #ifndef PI01
                    101: nlfund(sp)
                    102:        char *sp;
                    103: {
                    104:        register struct nl *p;
                    105:        register int i;
                    106: 
                    107:        i = (int) sp & 077;
                    108:        for (p = disptab[i]; p != NIL; p = p->nl_next)
                    109:        if (p->symbol == sp && (p->nl_block & 037) == 0)
                    110:                return (nloff(p));
                    111:        return (0);
                    112: }
                    113: #endif

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