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Annotation of 43BSDReno/pgrm/yacc/symtab.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1989 The Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * This code is derived from software contributed to Berkeley by
                      6:  * Robert Paul Corbett.
                      7:  *
                      8:  * Redistribution and use in source and binary forms are permitted provided
                      9:  * that: (1) source distributions retain this entire copyright notice and
                     10:  * comment, and (2) distributions including binaries display the following
                     11:  * acknowledgement:  ``This product includes software developed by the
                     12:  * University of California, Berkeley and its contributors'' in the
                     13:  * documentation or other materials provided with the distribution and in
                     14:  * all advertising materials mentioning features or use of this software.
                     15:  * Neither the name of the University nor the names of its contributors may
                     16:  * be used to endorse or promote products derived from this software without
                     17:  * specific prior written permission.
                     18:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
                     19:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
                     20:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     21:  */
                     22: 
                     23: #ifndef lint
                     24: static char sccsid[] = "@(#)symtab.c   5.3 (Berkeley) 6/1/90";
                     25: #endif /* not lint */
                     26: 
                     27: #include "defs.h"
                     28: 
                     29: /* TABLE_SIZE is the number of entries in the symbol table. */
                     30: /* TABLE_SIZE must be a power of two.                      */
                     31: 
                     32: #define        TABLE_SIZE 1024
                     33: 
                     34: 
                     35: bucket **symbol_table;
                     36: bucket *first_symbol;
                     37: bucket *last_symbol;
                     38: 
                     39: 
                     40: int
                     41: hash(name)
                     42: char *name;
                     43: {
                     44:     register char *s;
                     45:     register int c, k;
                     46: 
                     47:     assert(name && *name);
                     48:     s = name;
                     49:     k = *s;
                     50:     while (c = *++s)
                     51:        k = (31*k + c) & (TABLE_SIZE - 1);
                     52: 
                     53:     return (k);
                     54: }
                     55: 
                     56: 
                     57: bucket *
                     58: make_bucket(name)
                     59: char *name;
                     60: {
                     61:     register bucket *bp;
                     62: 
                     63:     assert(name);
                     64:     bp = (bucket *) MALLOC(sizeof(bucket));
                     65:     if (bp == 0) no_space();
                     66:     bp->link = 0;
                     67:     bp->next = 0;
                     68:     bp->name = MALLOC(strlen(name) + 1);
                     69:     if (bp->name == 0) no_space();
                     70:     bp->tag = 0;
                     71:     bp->value = UNDEFINED;
                     72:     bp->index = 0;
                     73:     bp->prec = 0;
                     74:     bp-> class = UNKNOWN;
                     75:     bp->assoc = TOKEN;
                     76: 
                     77:     if (bp->name == 0) no_space();
                     78:     strcpy(bp->name, name);
                     79: 
                     80:     return (bp);
                     81: }
                     82: 
                     83: 
                     84: bucket *
                     85: lookup(name)
                     86: char *name;
                     87: {
                     88:     register bucket *bp, **bpp;
                     89: 
                     90:     bpp = symbol_table + hash(name);
                     91:     bp = *bpp;
                     92: 
                     93:     while (bp)
                     94:     {
                     95:        if (strcmp(name, bp->name) == 0) return (bp);
                     96:        bpp = &bp->link;
                     97:        bp = *bpp;
                     98:     }
                     99: 
                    100:     *bpp = bp = make_bucket(name);
                    101:     last_symbol->next = bp;
                    102:     last_symbol = bp;
                    103: 
                    104:     return (bp);
                    105: }
                    106: 
                    107: 
                    108: create_symbol_table()
                    109: {
                    110:     register int i;
                    111:     register bucket *bp;
                    112: 
                    113:     symbol_table = (bucket **) MALLOC(TABLE_SIZE*sizeof(bucket *));
                    114:     if (symbol_table == 0) no_space();
                    115:     for (i = 0; i < TABLE_SIZE; i++)
                    116:        symbol_table[i] = 0;
                    117: 
                    118:     bp = make_bucket("error");
                    119:     bp->index = 1;
                    120:     bp->class = TERM;
                    121: 
                    122:     first_symbol = bp;
                    123:     last_symbol = bp;
                    124:     symbol_table[hash("error")] = bp;
                    125: }
                    126: 
                    127: 
                    128: free_symbol_table()
                    129: {
                    130:     FREE(symbol_table);
                    131:     symbol_table = 0;
                    132: }
                    133: 
                    134: 
                    135: free_symbols()
                    136: {
                    137:     register bucket *p, *q;
                    138: 
                    139:     for (p = first_symbol; p; p = q)
                    140:     {
                    141:        q = p->next;
                    142:        FREE(p);
                    143:     }
                    144: }

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