/* sym - symbol table routines */

/*  Copyright (c) 1990 The Regents of the University of California. */

/*  All rights reserved. */

/*  This code is derived from software contributed to Berkeley by */

/*  Vern Paxson. */

/*  The United States Government has rights in this work pursuant */

/*  to contract no. DE-AC03-76SF00098 between the United States */

/*  Department of Energy and the University of California. */

/*  This file is part of flex. */

/*  Redistribution and use in source and binary forms, with or without */

/*  modification, are permitted provided that the following conditions */

/*  are met: */

/*  1. Redistributions of source code must retain the above copyright */

/*     notice, this list of conditions and the following disclaimer. */

/*  2. Redistributions in binary form must reproduce the above copyright */

/*     notice, this list of conditions and the following disclaimer in the */

/*     documentation and/or other materials provided with the distribution. */

/*  Neither the name of the University nor the names of its contributors */

/*  may be used to endorse or promote products derived from this software */

/*  without specific prior written permission. */

/*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR */

/*  IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED */

/*  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */

/*  PURPOSE. */

#include "flexdef.h"

/* Variables for symbol tables:

 * sctbl - start-condition symbol table

 * ndtbl - name-definition symbol table

 * ccltab - character class text symbol table

 */

struct hash_entry {

	struct hash_entry *prev, *next;

	char   *name;

	char   *str_val;

	int     int_val;

};

typedef struct hash_entry **hash_table;

#define NAME_TABLE_HASH_SIZE 101

#define START_COND_HASH_SIZE 101

#define CCL_HASH_SIZE 101

static struct hash_entry *ndtbl[NAME_TABLE_HASH_SIZE];

static struct hash_entry *sctbl[START_COND_HASH_SIZE];

static struct hash_entry *ccltab[CCL_HASH_SIZE];

/* declare functions that have forward references */

static int addsym(char[], char *, int, hash_table, int);

static struct hash_entry *findsym (const char *sym, hash_table table,

				   int table_size);

static int hashfunct(const char *, int);

/* addsym - add symbol and definitions to symbol table

 *

 * -1 is returned if the symbol already exists, and the change not made.

 */

static int addsym (char sym[], char *str_def, int int_def, hash_table table, int table_size)

{

	int    hash_val = hashfunct (sym, table_size);

	struct hash_entry *sym_entry = table[hash_val];

	struct hash_entry *new_entry;

	struct hash_entry *successor;

	while (sym_entry) {

		if (!strcmp (sym, sym_entry->name)) {	/* entry already exists */

			return -1;

		}

		sym_entry = sym_entry->next;

	}

	/* create new entry */

	new_entry = malloc(sizeof(struct hash_entry));

	if (new_entry == NULL)

		flexfatal (_("symbol table memory allocation failed"));

	if ((successor = table[hash_val]) != 0) {

		new_entry->next = successor;

		successor->prev = new_entry;

	}

	else

		new_entry->next = NULL;

	new_entry->prev = NULL;

	new_entry->name = sym;

	new_entry->str_val = str_def;

	new_entry->int_val = int_def;

	table[hash_val] = new_entry;

	return 0;

}

/* cclinstal - save the text of a character class */

void    cclinstal (char ccltxt[], int cclnum)

{

	/* We don't bother checking the return status because we are not

	 * called unless the symbol is new.

	 */

	(void) addsym (xstrdup(ccltxt),

		       (char *) 0, cclnum, ccltab, CCL_HASH_SIZE);

}

/* ccllookup - lookup the number associated with character class text

 *

 * Returns 0 if there's no CCL associated with the text.

 */

int     ccllookup (char ccltxt[])

{

	return findsym (ccltxt, ccltab, CCL_HASH_SIZE)->int_val;

}

/* findsym - find symbol in symbol table */

static struct hash_entry *findsym (const char *sym, hash_table table, int table_size)

{

	static struct hash_entry empty_entry = {

		NULL, NULL, NULL, NULL, 0,

	};

	struct hash_entry *sym_entry =

		table[hashfunct (sym, table_size)];

	while (sym_entry) {

		if (!strcmp (sym, sym_entry->name))

			return sym_entry;

		sym_entry = sym_entry->next;

	}

	return &empty_entry;

}

/* hashfunct - compute the hash value for "str" and hash size "hash_size" */

static int hashfunct (const char *str, int hash_size)

{

	int hashval;

	int locstr;

	hashval = 0;

	locstr = 0;

	while (str[locstr]) {

		hashval = (hashval << 1) + (unsigned char) str[locstr++];

		hashval %= hash_size;

	}

	return hashval;

}

/* ndinstal - install a name definition */

void    ndinstal (const char *name, char definition[])

{

	if (addsym (xstrdup(name),

		    xstrdup(definition), 0,

		    ndtbl, NAME_TABLE_HASH_SIZE))

			synerr (_("name defined twice"));

}

/* ndlookup - lookup a name definition

 *

 * Returns a nil pointer if the name definition does not exist.

 */

char   *ndlookup (const char *nd)

{

	return findsym (nd, ndtbl, NAME_TABLE_HASH_SIZE)->str_val;

}

/* scextend - increase the maximum number of start conditions */

void    scextend (void)

{

	current_max_scs += MAX_SCS_INCREMENT;

	++num_reallocs;

	scset = reallocate_integer_array (scset, current_max_scs);

	scbol = reallocate_integer_array (scbol, current_max_scs);

	scxclu = reallocate_integer_array (scxclu, current_max_scs);

	sceof = reallocate_integer_array (sceof, current_max_scs);

	scname = reallocate_char_ptr_array (scname, current_max_scs);

}

/* scinstal - make a start condition

 *

 * NOTE

 *    The start condition is "exclusive" if xcluflg is true.

 */

void    scinstal (const char *str, int xcluflg)

{

	if (++lastsc >= current_max_scs)

		scextend ();

	scname[lastsc] = xstrdup(str);

	if (addsym(scname[lastsc], NULL, lastsc,

		    sctbl, START_COND_HASH_SIZE))

			format_pinpoint_message (_

						 ("start condition %s declared twice"),

str);

	scset[lastsc] = mkstate (SYM_EPSILON);

	scbol[lastsc] = mkstate (SYM_EPSILON);

	scxclu[lastsc] = xcluflg;

	sceof[lastsc] = false;

}

/* sclookup - lookup the number associated with a start condition

 *

 * Returns 0 if no such start condition.

 */

int     sclookup (const char *str)

{

	return findsym (str, sctbl, START_COND_HASH_SIZE)->int_val;

}