src/lib-roff/symbol.cpp

   1 /*@
   2  * Copyright (c) 2014 - 2015 Steffen (Daode) Nurpmeso <sdaoden@users.sf.net>.
   3  *
   4  * Copyright (C) 1989 - 1992, 2002, 2004
   5  *    Free Software Foundation, Inc.
   6  *      Written by James Clark (jjc@jclark.com)
   7  *
   8  * This is free software; you can redistribute it and/or modify it under
   9  * the terms of the GNU General Public License as published by the Free
  10  * Software Foundation; either version 2, or (at your option) any later
  11  * version.
  12  *
  13  * This is distributed in the hope that it will be useful, but WITHOUT ANY
  14  * WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16  * for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with groff; see the file COPYING.  If not, write to the Free Software
  20  * Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA.
  21  */
  22
  23 #include "config.h"
  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 const int BLOCK_SIZE = 1024;
  43 // the table will increase in size as necessary
  44 // the size will be chosen from the following array
  45 // add some more if you want
  46 static const unsigned int table_sizes[] = {
  47   101, 503, 1009, 2003, 3001, 4001, 5003, 10007, 20011, 40009, 80021,
  48   160001, 500009, 1000003, 1500007, 2000003, 0
  49 };
  50 const double FULL_MAX = 0.3;    // don't let the table get more than this full
  51
  52 symbol default_symbol("default");
  53
  54 static unsigned int hash_string(const char *p) /* FIXME Torek's hash */
  55 {
  56   // compute a hash code; this assumes 32-bit unsigned ints
  57   // see p436 of  Compilers by Aho, Sethi & Ullman
  58   // give special treatment to two-character names
  59   unsigned int hc = 0, g;
  60   if (*p != 0) {
  61     hc = *p++;
  62     if (*p != 0) {
  63       hc <<= 7;
  64       hc += *p++;
  65       for (; *p != 0; p++) {
  66         hc <<= 4;
  67         hc += *p;
  68         if ((g = (hc & 0xf0000000)) == 0) {
  69           hc ^= g >> 24;
  70           hc ^= g;
  71         }
  72       }
  73     }
  74   }
  75   return hc;
  76 }
  77
  78 // Tell compiler that a variable is intentionally unused.
  79 inline void unused(void *) { }
  80
  81 symbol::symbol(const char *p, int how)
  82 {
  83   if (p == 0) {
  84     s = 0;
  85     return;
  86   }
  87   if (*p == 0) {
  88     s = "";
  89     return;
  90   }
  91   if (table == 0) {
  92     table_size = table_sizes[0];
  93     table = (const char **)new char*[table_size];
  94     for (int i = 0; i < table_size; i++)
  95       table[i] = 0;
  96     table_used = 0;
  97   }
  98   unsigned int hc = hash_string(p);
  99   const char **pp;
 100   for (pp = table + hc % table_size;
 101        *pp != 0;
 102        (pp == table ? pp = table + table_size - 1 : --pp))
 103     if (strcmp(p, *pp) == 0) {
 104       s = *pp;
 105       return;
 106     }
 107   if (how == MUST_ALREADY_EXIST) {
 108     s = 0;
 109     return;
 110   }
 111   if (table_used  >= table_size - 1 || table_used >= table_size*FULL_MAX) {
 112     const char **old_table = table;
 113     unsigned int old_table_size = table_size;
 114     int i;
 115     for (i = 1; table_sizes[i] <= old_table_size; i++)
 116       if (table_sizes[i] == 0)
 117         fatal("too many symbols");
 118     table_size = table_sizes[i];
 119     table_used = 0;
 120     table = (const char **)new char*[table_size];
 121     for (i = 0; i < table_size; i++)
 122       table[i] = 0;
 123     for (pp = old_table + old_table_size - 1;
 124          pp >= old_table;
 125          --pp) {
 126            symbol temp(*pp, 1); /* insert it into the new table */
 127            unused(&temp);
 128          }
 129     a_delete old_table;
 130     for (pp = table + hc % table_size;
 131          *pp != 0;
 132          (pp == table ? pp = table + table_size - 1 : --pp))
 133       ;
 134   }
 135   ++table_used;
 136   if (how == DONT_STORE) {
 137     s = *pp = p;
 138   }
 139   else {
 140     int len = strlen(p)+1;
 141     if (block == 0 || block_size < len) {
 142       block_size = len > BLOCK_SIZE ? len : BLOCK_SIZE;
 143       block = new char [block_size];
 144     }
 145     (void)strcpy(block, p);
 146     s = *pp = block;
 147     block += len;
 148     block_size -= len;
 149   }
 150 }
 151
 152 symbol concat(symbol s1, symbol s2)
 153 {
 154   char *buf = new char [strlen(s1.contents()) + strlen(s2.contents()) + 1];
 155   strcpy(buf, s1.contents());
 156   strcat(buf, s2.contents());
 157   symbol res(buf);
 158   a_delete buf;
 159   return res;
 160 }
 161
 162 // s-it2-mode