/* Copyright (C) 1999 Aladdin Enterprises.  All rights reserved.
  
  This file is part of AFPL Ghostscript.
  
  AFPL Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author or
  distributor accepts any responsibility for the consequences of using it, or
  for whether it serves any particular purpose or works at all, unless he or
  she says so in writing.  Refer to the Aladdin Free Public License (the
  "License") for full details.
  
  Every copy of AFPL Ghostscript must include a copy of the License, normally
  in a plain ASCII text file named PUBLIC.  The License grants you the right
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*/

/*$Id: inamestr.h,v 1.2 2000/09/19 19:00:45 lpd 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 */
