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/* LibHnj is dual licensed under LGPL and MPL. Boilerplate for both
* licenses follows.
*/
/* LibHnj - a library for high quality hyphenation and justification
* Copyright (C) 1998 Raph Levien
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307 USA.
*/
/*
* The contents of this file are subject to the Mozilla Public License
* Version 1.0 (the "MPL"); you may not use this file except in
* compliance with the MPL. You may obtain a copy of the MPL at
* http://www.mozilla.org/MPL/
*
* Software distributed under the MPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the MPL
* for the specific language governing rights and limitations under the
* MPL.
*
*/
/* A module for a simple "name context", i.e. lisp-style atoms */
#include <string.h>
#include "z_misc.h"
#include "namecontext.h"
/* btw, I do not know who wrote the following comment. I modified this
file somewhat from gimp's app/procedural_db.c hash function. */
static unsigned int
name_context_hash_func (char *string)
{
unsigned int result;
int c;
int i;
/*
* I tried a zillion different hash functions and asked many other
* people for advice. Many people had their own favorite functions,
* all different, but no-one had much idea why they were good ones.
* I chose the one below (multiply by 9 and add new character)
* because of the following reasons:
*
* 1. Multiplying by 10 is perfect for keys that are decimal strings,
* and multiplying by 9 is just about as good.
* 2. Times-9 is (shift-left-3) plus (old). This means that each
* character's bits hang around in the low-order bits of the
* hash value for ever, plus they spread fairly rapidly up to
* the high-order bits to fill out the hash value. This seems
* works well both for decimal and non-decimal strings.
*
* tclHash.c --
*
* Implementation of in-memory hash tables for Tcl and Tcl-based
* applications.
*
* Copyright (c) 1991-1993 The Regents of the University of California.
* Copyright (c) 1994 Sun Microsystems, Inc.
*/
result = 0;
for (i = 0; (c = ((unsigned char *)string)[i]) != '\0'; i++)
result += (result << 3) + c;
return result;
}
static unsigned int
name_context_hash_func_size (char *string, int size)
{
unsigned int result;
int i;
result = 0;
for (i = 0; i < size; i++)
result += (result << 3) + ((unsigned char *)string)[i];
return result;
}
NameContext *
name_context_new (void)
{
NameContext *nc;
int i;
nc = z_new (NameContext, 1);
nc->num_entries = 0;
nc->table_size = 16;
nc->table = z_new (NameContextHashEntry, nc->table_size);
for (i = 0; i < nc->table_size; i++)
nc->table[i].name = NULL;
return nc;
}
void
name_context_free (NameContext *nc)
{
int i;
for (i = 0; i < nc->table_size; i++)
if (nc->table[i].name != NULL)
z_free (nc->table[i].name);
z_free (nc->table);
z_free (nc);
}
static char *
name_context_strdup (char *s)
{
int len;
char *new;
len = strlen (s);
new = z_new (char, len + 1);
memcpy (new, s, len);
new[len] = '\0';
return new;
}
static z_boolean
name_context_streq_size (char *s1, char *s2, int size2)
{
int i;
/* could rewrite for 32 bits at a time, but I wouldn't worry */
for (i = 0; i < size2; i++)
if (s1[i] != s2[i])
return z_false;
return s1[i] == 0;
}
static char *
name_context_strdup_size (char *s, int size)
{
char *new;
new = z_new (char, size + 1);
memcpy (new, s, size);
new[size] = '\0';
return new;
}
/* double the size of the hash table, rehashing as needed */
static void
name_context_double (NameContext *nc)
{
int i, j;
int oldsize, newmask;
NameContextHashEntry *old_table, *new_table;
oldsize = nc->table_size;
old_table = nc->table;
nc->table_size = oldsize << 1;
newmask = nc->table_size - 1;
new_table = z_new (NameContextHashEntry, nc->table_size);
for (j = 0; j < nc->table_size; j++)
new_table[j].name = NULL;
for (i = 0; i < oldsize; i++)
{
if (old_table[i].name)
{
for (j = name_context_hash_func(old_table[i].name);
new_table[j & newmask].name;
j++);
new_table[j & newmask] = old_table[i];
}
}
z_free (old_table);
nc->table = new_table;
}
/* Return the unique (to this name context) nameid for the given string,
allocating a new one if necessary. */
NameId
name_context_intern (NameContext *nc, char *name)
{
int i;
int mask;
mask = nc->table_size - 1;
for (i = name_context_hash_func (name); nc->table[i & mask].name; i++)
if (!strcmp (nc->table[i & mask].name, name))
return nc->table[i & mask].nameid;
/* not found, allocate a new one */
if (nc->num_entries >= nc->table_size >> 1)
{
name_context_double (nc);
mask = nc->table_size - 1;
for (i = name_context_hash_func (name); nc->table[i & mask].name; i++);
}
i &= mask;
nc->table[i].name = name_context_strdup (name);
nc->table[i].nameid = nc->num_entries;
return nc->num_entries++;
}
/* Return the unique (to this name context) nameid for the given
string, allocating a new one if necessary. The string is not
necessarily null-terminated; the size is given explicitly. */
NameId
name_context_intern_size (NameContext *nc, char *name, int size)
{
int i;
int mask;
mask = nc->table_size - 1;
for (i = name_context_hash_func_size (name, size);
nc->table[i & mask].name;
i++)
if (name_context_streq_size (nc->table[i & mask].name, name, size))
return nc->table[i & mask].nameid;
/* not found, allocate a new one */
if (nc->num_entries >= nc->table_size >> 1)
{
name_context_double (nc);
mask = nc->table_size - 1;
for (i = name_context_hash_func_size (name, size);
nc->table[i & mask].name;
i++);
}
i &= mask;
nc->table[i].name = name_context_strdup_size (name, size);
nc->table[i].nameid = nc->num_entries;
return nc->num_entries++;
}
/* This one is slow - it's intended for debugging only */
char *
name_context_string (NameContext *nc, NameId nameid)
{
int j;
for (j = 0; j < nc->table_size; j++)
if (nc->table[j].name && nc->table[j].nameid == nameid)
return nc->table[j].name;
return NULL;
}
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