projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| dfd13e7c PK |
1 | /* Copyright (c) 1979 Regents of the University of California */ |
| 2 | ||
| 31cef89c | 3 | static char sccsid[] = "@(#)lookup.c 1.1 8/27/80"; |
| dfd13e7c PK |
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 |