gnu/dist/groff/src/libs/libgroff/symbol.cpp

   1 /*      $NetBSD$        */
   2
   3 // -*- C++ -*-
   4 /* Copyright (C) 1989, 1990, 1991, 1992, 2002, 2004
   5    Free Software Foundation, Inc.
   6      Written by James Clark (jjc@jclark.com)
   7
   8 This file is part of groff.
   9
  10 groff is free software; you can redistribute it and/or modify it under
  11 the terms of the GNU General Public License as published by the Free
  12 Software Foundation; either version 2, or (at your option) any later
  13 version.
  14
  15 groff is distributed in the hope that it will be useful, but WITHOUT ANY
  16 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  17 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  18 for more details.
  19
  20 You should have received a copy of the GNU General Public License along
  21 with groff; see the file COPYING.  If not, write to the Free Software
  22 Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA. */
  23
  24 #include "lib.h"
  25
  26 #include "errarg.h"
  27 #include "error.h"
  28 #include "symbol.h"
  29
  30 const char **symbol::table = 0;
  31 int symbol::table_used = 0;
  32 int symbol::table_size = 0;
  33 char *symbol::block = 0;
  34 int symbol::block_size = 0;
  35
  36 const symbol NULL_SYMBOL;
  37 const symbol EMPTY_SYMBOL("");
  38
  39 #ifdef BLOCK_SIZE
  40 #undef BLOCK_SIZE
  41 #endif
  42
  43 const int BLOCK_SIZE = 1024;
  44 // the table will increase in size as necessary
  45 // the size will be chosen from the following array
  46 // add some more if you want
  47 static const unsigned int table_sizes[] = {
  48   101, 503, 1009, 2003, 3001, 4001, 5003, 10007, 20011, 40009, 80021,
  49   160001, 500009, 1000003, 1500007, 2000003, 0
  50 };
  51 const double FULL_MAX = 0.3;    // don't let the table get more than this full
  52
  53 static unsigned int hash_string(const char *p)
  54 {
  55   // compute a hash code; this assumes 32-bit unsigned ints
  56   // see p436 of  Compilers by Aho, Sethi & Ullman
  57   // give special treatment to two-character names
  58   unsigned int hc = 0, g;
  59   if (*p != 0) {
  60     hc = *p++;
  61     if (*p != 0) {
  62       hc <<= 7;
  63       hc += *p++;
  64       for (; *p != 0; p++) {
  65         hc <<= 4;
  66         hc += *p;
  67         if ((g = (hc & 0xf0000000)) == 0) {
  68           hc ^= g >> 24;
  69           hc ^= g;
  70         }
  71       }
  72     }
  73   }
  74   return hc;
  75 }
  76
  77 // Tell compiler that a variable is intentionally unused.
  78 inline void unused(void *) { }
  79
  80 symbol::symbol(const char *p, int how)
  81 {
  82   if (p == 0) {
  83     s = 0;
  84     return;
  85   }
  86   if (*p == 0) {
  87     s = "";
  88     return;
  89   }
  90   if (table == 0) {
  91     table_size = table_sizes[0];
  92     table = (const char **)new char*[table_size];
  93     for (int i = 0; i < table_size; i++)
  94       table[i] = 0;
  95     table_used = 0;
  96   }
  97   unsigned int hc = hash_string(p);
  98   const char **pp;
  99   for (pp = table + hc % table_size;
 100        *pp != 0;
 101        (pp == table ? pp = table + table_size - 1 : --pp))
 102     if (strcmp(p, *pp) == 0) {
 103       s = *pp;
 104       return;
 105     }
 106   if (how == MUST_ALREADY_EXIST) {
 107     s = 0;
 108     return;
 109   }
 110   if (table_used  >= table_size - 1 || table_used >= table_size*FULL_MAX) {
 111     const char **old_table = table;
 112     unsigned int old_table_size = table_size;
 113     int i;
 114     for (i = 1; table_sizes[i] <= old_table_size; i++)
 115       if (table_sizes[i] == 0)
 116         fatal("too many symbols");
 117     table_size = table_sizes[i];
 118     table_used = 0;
 119     table = (const char **)new char*[table_size];
 120     for (i = 0; i < table_size; i++)
 121       table[i] = 0;
 122     for (pp = old_table + old_table_size - 1;
 123          pp >= old_table;
 124          --pp) {
 125            symbol temp(*pp, 1); /* insert it into the new table */
 126            unused(&temp);
 127          }
 128     a_delete old_table;
 129     for (pp = table + hc % table_size;
 130          *pp != 0;
 131          (pp == table ? pp = table + table_size - 1 : --pp))
 132       ;
 133   }
 134   ++table_used;
 135   if (how == DONT_STORE) {
 136     s = *pp = p;
 137   }
 138   else {
 139     int len = strlen(p)+1;
 140     if (block == 0 || block_size < len) {
 141       block_size = len > BLOCK_SIZE ? len : BLOCK_SIZE;
 142       block = new char [block_size];
 143     }
 144     (void)strcpy(block, p);
 145     s = *pp = block;
 146     block += len;
 147     block_size -= len;
 148   }
 149 }
 150
 151 symbol concat(symbol s1, symbol s2)
 152 {
 153   char *buf = new char [strlen(s1.contents()) + strlen(s2.contents()) + 1];
 154   strcpy(buf, s1.contents());
 155   strcat(buf, s2.contents());
 156   symbol res(buf);
 157   a_delete buf;
 158   return res;
 159 }
 160
 161 symbol default_symbol("default");