symtab.c

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/*************************************************************************\
* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
*     National Laboratory.
* Copyright (c) 2002 The Regents of the University of California, as
*     Operator of Los Alamos National Laboratory.
* EPICS BASE is distributed subject to a Software License Agreement found
* in file LICENSE that is included with this distribution.
\*************************************************************************/
#include "defs.h"


/* TABLE_SIZE is the number of entries in the symbol table. */
/* TABLE_SIZE must be a power of two.                       */

#define TABLE_SIZE 1024


bucket **symbol_table;
bucket *first_symbol;
bucket *last_symbol;


static int
hash(char *name)
{
    char *s;
    int c, k;

    assert(name && *name);
    s = name;
    k = *s;
    while ((c = *++s))
        k = (31*k + c) & (TABLE_SIZE - 1);

    return (k);
}


bucket *
make_bucket(char *name)
{
    bucket *bp;

    assert(name);
    bp = (bucket *) MALLOC(sizeof(bucket));
    if (bp == 0) no_space();
    bp->link = 0;
    bp->next = 0;
    bp->name = MALLOC(strlen(name) + 1);
    if (bp->name == 0) no_space();
    bp->tag = 0;
    bp->value = UNDEFINED;
    bp->index = 0;
    bp->prec = 0;
    bp-> class = UNKNOWN;
    bp->assoc = TOKEN;

    if (bp->name == 0) no_space();
    strcpy(bp->name, name);

    return (bp);
}


bucket *
lookup(char *name)
{
    bucket *bp, **bpp;

    bpp = symbol_table + hash(name);
    bp = *bpp;

    while (bp)
    {
        if (strcmp(name, bp->name) == 0) return (bp);
        bpp = &bp->link;
        bp = *bpp;
    }

    *bpp = bp = make_bucket(name);
    last_symbol->next = bp;
    last_symbol = bp;

    return (bp);
}

void
create_symbol_table(void)
{
    int i;
    bucket *bp;

    symbol_table = (bucket **) MALLOC(TABLE_SIZE*sizeof(bucket *));
    if (symbol_table == 0) no_space();
    for (i = 0; i < TABLE_SIZE; i++)
        symbol_table[i] = 0;

    bp = make_bucket("error");
    bp->index = 1;
    bp->class = TERM;

    first_symbol = bp;
    last_symbol = bp;
    symbol_table[hash("error")] = bp;
}


void
free_symbol_table(void)
{
    FREE(symbol_table);
    symbol_table = 0;
}


void
free_symbols(void)
{
    bucket *p, *q;

    for (p = first_symbol; p; p = q)
    {
        q = p->next;
        FREE(p);
    }
}