/* Copyright (C) 1999 artofcode LLC.  All rights reserved.
  
  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2 of the License, or (at your
  option) any later version.

  This program 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
  General Public License for more details.

  You should have received a copy of the GNU General Public License along
  with this program; if not, write to the Free Software Foundation, Inc.,
  59 Temple Place, Suite 330, Boston, MA, 02111-1307.

*/

/*$Id: inamestr.h,v 1.2.6.1.2.1 2003/01/17 00:49:04 giles Exp $ */
/* Name table strings definition */

#ifndef inamestr_INCLUDED
#  define inamestr_INCLUDED

#include "inameidx.h"

/*
 * In the code below, we use the hashing method described in
 * "Fast Hashing of Variable-Length Text Strings" by Peter K. Pearson,
 * pp. 677-680, CACM 33(6), June 1990.
 */

/*
 * Define a pseudo-random permutation of the integers 0..255.
 * Pearson's article claims this permutation gave good results.
 */
#define NAME_HASH_PERMUTATION_DATA\
   1, 87, 49, 12, 176, 178, 102, 166, 121, 193, 6, 84, 249, 230, 44, 163,\
   14, 197, 213, 181, 161, 85, 218, 80, 64, 239, 24, 226, 236, 142, 38, 200,\
   110, 177, 104, 103, 141, 253, 255, 50, 77, 101, 81, 18, 45, 96, 31, 222,\
   25, 107, 190, 70, 86, 237, 240, 34, 72, 242, 20, 214, 244, 227, 149, 235,\
   97, 234, 57, 22, 60, 250, 82, 175, 208, 5, 127, 199, 111, 62, 135, 248,\
   174, 169, 211, 58, 66, 154, 106, 195, 245, 171, 17, 187, 182, 179, 0, 243,\
   132, 56, 148, 75, 128, 133, 158, 100, 130, 126, 91, 13, 153, 246, 216, 219,\
   119, 68, 223, 78, 83, 88, 201, 99, 122, 11, 92, 32, 136, 114, 52, 10,\
   138, 30, 48, 183, 156, 35, 61, 26, 143, 74, 251, 94, 129, 162, 63, 152,\
   170, 7, 115, 167, 241, 206, 3, 150, 55, 59, 151, 220, 90, 53, 23, 131,\
   125, 173, 15, 238, 79, 95, 89, 16, 105, 137, 225, 224, 217, 160, 37, 123,\
   118, 73, 2, 157, 46, 116, 9, 145, 134, 228, 207, 212, 202, 215, 69, 229,\
   27, 188, 67, 124, 168, 252, 42, 4, 29, 108, 21, 247, 19, 205, 39, 203,\
   233, 40, 186, 147, 198, 192, 155, 33, 164, 191, 98, 204, 165, 180, 117, 76,\
   140, 36, 210, 172, 41, 54, 159, 8, 185, 232, 113, 196, 231, 47, 146, 120,\
   51, 65, 28, 144, 254, 221, 93, 189, 194, 139, 112, 43, 71, 109, 184, 209

/* Compute the hash for a name string.  Assume size >= 1. */
#define NAME_HASH(hash, hperm, ptr, size)\
  BEGIN\
    const byte *p = ptr;\
    uint n = size;\
\
    hash = hperm[*p++];\
    while (--n > 0)\
	hash = (hash << 8) | hperm[(byte)hash ^ *p++];\
  END

/*
 * Define the structure for a name string.  The next_index "pointer" is used
 * both for the chained hash table in the name_table and for the list of
 * free names.
 */
typedef struct name_string_s {
#if EXTEND_NAMES
#  define name_extension_bits 6
#else
#  define name_extension_bits 0
#endif
    unsigned next_index:16 + name_extension_bits; /* next name in chain or 0 */
    unsigned foreign_string:1;	/* string is allocated statically */
    unsigned mark:1;		/* GC mark bit of index for this name */
#define name_string_size_bits (14 - name_extension_bits)
#define max_name_string ((1 << name_string_size_bits) - 1)
    unsigned string_size:name_string_size_bits;
    const byte *string_bytes;
} name_string_t;
#define name_next_index(nidx, pnstr)\
   ((pnstr)->next_index)
#define set_name_next_index(nidx, pnstr, next)\
   ((pnstr)->next_index = (next))

/* Define a sub-table of name strings. */
typedef struct name_string_sub_table_s {
    name_string_t strings[NT_SUB_SIZE];
} name_string_sub_table_t;

/* Define the size of the name hash table. */
#define NT_HASH_SIZE (1024 << (EXTEND_NAMES / 2))  /* must be a power of 2 */

#endif /* inamestr_INCLUDED */