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[storin] / sym.h

/* -*-c-*-
 *
 * $Id: sym.h,v 1.1 2000/05/21 11:28:30 mdw Exp $
 *
 * Symbol table management
 *
 * (c) 1998 Straylight
 * (c) 2000 Mark Wooding
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * Copyright (c) 2000 Mark Wooding
 * All rights reserved.
 * 
 * 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.
 * 
 * 3. The name of the authors may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 * 
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 * NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Instead of accepting the above terms, you may redistribute and/or modify
 * this software under the terms of either the GNU General Public License,
 * or the GNU Library General Public License, published by the Free
 * Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 */

/*----- Revision history --------------------------------------------------*
 *
 * $Log: sym.h,v $
 * Revision 1.1  2000/05/21 11:28:30  mdw
 * Initial check-in.
 *
 * --- Past lives (Become) --- *
 *
 * Revision 1.3  1998/01/12 16:46:30  mdw
 * Fix copyright date.
 *
 * Revision 1.2  1997/08/04 10:24:25  mdw
 * Sources placed under CVS control.
 *
 * Revision 1.1  1997/07/21  13:47:43  mdw
 * Initial revision
 *
 */

#ifndef SYM_H
#define SYM_H

#ifdef __cplusplus
  extern "C" {
#endif

/*----- Required headers --------------------------------------------------*/

#include <stddef.h>

#ifndef BITS_H
#  include "bits.h"
#endif

/*----- Type definitions --------------------------------------------------*/

/* --- Symbol table --- *
 *
 * A @sym_table@ contains the information needed to manage a symbol table.
 * Users shouldn't fiddle with this information directly, but it needs to be
 * here so that objects of the correct type can be created.
 */

typedef struct sym_table {
  uint32 mask;                          /* Bit mask for hashing purposes */
  size_t c;                             /* Down counter for growing table */
  struct sym_base **a;                  /* Array of hash bins */
} sym_table;

/* --- A symbol table entry --- *
 *
 * I don't care what actually gets stored in symbol entries because I don't
 * create them: that's the responsibility of my client.  All I care about
 * here is that whatever gets passed to me is a structure whose first member
 * is a @sym_base@.  The ANSI guarantees about structure layout are
 * sufficient to allow me to manipulate such objects.
 */

typedef struct sym_base {
  struct sym_base *next;                /* Next symbol in hash bin */
  uint32 hash;                          /* Hash value for symbol's name */
  char *name;                           /* Name of this symbol */
  size_t len;                           /* Length of the symbol's name */
} sym_base;

/* --- An iterator block --- */

typedef struct sym_iter {
  sym_table *t;                         /* Symbol table being iterated */
  sym_base *n;                          /* Address of next item to return */
  size_t i;                             /* Index of next hash bin to use */
} sym_iter;

/*----- External functions ------------------------------------------------*/

/* --- @sym_create@ --- *
 *
 * Arguments:   @sym_table *t@ = symbol table to initialize
 *
 * Returns:     ---
 *
 * Use:         Initialises the given symbol table.
 */

extern void sym_create(sym_table */*t*/);

/* --- @sym_destroy@ --- *
 *
 * Arguments:   @sym_table *t@ = pointer to symbol table in question
 *
 * Returns:     ---
 *
 * Use:         Destroys a symbol table, freeing all the memory it used to
 *              occupy.
 */

extern void sym_destroy(sym_table */*t*/);

/* --- @sym_find@ --- *
 *
 * Arguments:   @sym_table *t@ = pointer to symbol table in question
 *              @const char *n@ = pointer to symbol table to look up
 *              @long l@ = length of the name string or negative to measure
 *              @size_t sz@ = size of desired symbol object, or zero
 *              @unsigned *f@ = pointer to a flag, or null.
 *
 * Returns:     The address of a @sym_base@ structure, or null if not found
 *              and @sz@ is zero.
 *
 * Use:         Looks up a symbol in a given symbol table.  The name is
 *              passed by the address of its first character.  The length
 *              may be given, in which case the name may contain arbitrary
 *              binary data, or it may be given as a negative number, in
 *              which case the length of the name is calculated as
 *              @strlen(n)@.
 *
 *              The return value is the address of a pointer to a @sym_base@
 *              block (which may have other things on the end, as above).  If
 *              the symbol could be found, the return value points to the
 *              symbol block.  If the symbol wasn't there, then if @sz@ is
 *              nonzero, a new symbol is created and its address is returned;
 *              otherwise a null pointer is returned.
 *
 *              The value of @*f@ indicates whether a new symbol entry was
 *              created: a nonzero value indicates that an old value was
 *              found.
 */

extern void *sym_find(sym_table */*t*/, const char */*n*/, long /*l*/,
                      size_t /*sz*/, unsigned */*f*/);

/* --- @sym_remove@ --- *
 *
 * Arguments:   @sym_table *i@ = pointer to a symbol table object
 *              @void *b@ = pointer to symbol table entry
 *
 * Returns:     ---
 *
 * Use:         Removes the object from the symbol table.  The space occupied
 *              by the object and its name is freed; anything else attached
 *              to the entry should already be gone by this point.
 */

extern void sym_remove(sym_table */*t*/, void */*b*/);

/* --- @sym_mkiter@ --- *
 *
 * Arguments:   @sym_iter *i@ = pointer to an iterator object
 *              @sym_table *t@ = pointer to a symbol table object
 *
 * Returns:     ---
 *
 * Use:         Creates a new symbol table iterator which may be used to
 *              iterate through a symbol table.
 */

extern void sym_mkiter(sym_iter */*i*/, sym_table */*t*/);

/* --- @sym_next@ --- *
 *
 * Arguments:   @sym_iter *i@ = pointer to iterator object
 *
 * Returns:     Pointer to the next symbol found, or null when finished.
 *
 * Use:         Returns the next symbol from the table.  Symbols are not
 *              returned in any particular order.
 */

extern void *sym_next(sym_iter */*i*/);

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif