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Diffstat (limited to 'contrib/groff/troff/dictionary.cc')
| -rw-r--r-- | contrib/groff/troff/dictionary.cc | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/contrib/groff/troff/dictionary.cc b/contrib/groff/troff/dictionary.cc new file mode 100644 index 0000000..fc71e3c --- /dev/null +++ b/contrib/groff/troff/dictionary.cc @@ -0,0 +1,212 @@ +// -*- C++ -*- +/* Copyright (C) 1989, 1990, 1991, 1992 Free Software Foundation, Inc. + Written by James Clark (jjc@jclark.com) + +This file is part of groff. + +groff 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, or (at your option) any later +version. + +groff 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 groff; see the file COPYING. If not, write to the Free Software +Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + + +#include "troff.h" +#include "symbol.h" +#include "dictionary.h" + +// is `p' a good size for a hash table + +static int is_good_size(int p) +{ + const int SMALL = 10; + unsigned i; + for (i = 2; i <= p/2; i++) + if (p % i == 0) + return 0; + for (i = 0x100; i != 0; i <<= 8) + if (i % p <= SMALL || i % p > p - SMALL) + return 0; + return 1; +} + +dictionary::dictionary(int n) : threshold(0.5), factor(1.5), used(0), size(n) +{ + table = new association[n]; +} + +// see Knuth, Sorting and Searching, p518, Algorithm L +// we can't use double-hashing because we want a remove function + +void *dictionary::lookup(symbol s, void *v) +{ + int i; + for (i = int(s.hash() % size); + table[i].v != 0; + i == 0 ? i = size - 1: --i) + if (s == table[i].s) { + if (v != 0) { + void *temp = table[i].v; + table[i].v = v; + return temp; + } + else + return table[i].v; + } + if (v == 0) + return 0; + ++used; + table[i].v = v; + table[i].s = s; + if ((double)used/(double)size >= threshold || used + 1 >= size) { + int old_size = size; + size = int(size*factor); + while (!is_good_size(size)) + ++size; + association *old_table = table; + table = new association[size]; + used = 0; + for (i = 0; i < old_size; i++) + if (old_table[i].v != 0) + (void)lookup(old_table[i].s, old_table[i].v); + a_delete old_table; + } + return 0; +} + +void *dictionary::lookup(const char *p) +{ + symbol s(p, MUST_ALREADY_EXIST); + if (s.is_null()) + return 0; + else + return lookup(s); +} + +// see Knuth, Sorting and Searching, p527, Algorithm R + +void *dictionary::remove(symbol s) +{ + // this relies on the fact that we are using linear probing + int i; + for (i = int(s.hash() % size); + table[i].v != 0 && s != table[i].s; + i == 0 ? i = size - 1: --i) + ; + void *p = table[i].v; + while (table[i].v != 0) { + table[i].v = 0; + int j = i; + int r; + do { + --i; + if (i < 0) + i = size - 1; + if (table[i].v == 0) + break; + r = int(table[i].s.hash() % size); + } while ((i <= r && r < j) || (r < j && j < i) || (j < i && i <= r)); + table[j] = table[i]; + } + if (p != 0) + --used; + return p; +} + +dictionary_iterator::dictionary_iterator(dictionary &d) : dict(&d), i(0) +{ +} + +int dictionary_iterator::get(symbol *sp, void **vp) +{ + for (; i < dict->size; i++) + if (dict->table[i].v) { + *sp = dict->table[i].s; + *vp = dict->table[i].v; + i++; + return 1; + } + return 0; +} + +object_dictionary_iterator::object_dictionary_iterator(object_dictionary &od) + : di(od.d) +{ +} + +object::object() : rcount(0) +{ +} + +object::~object() +{ +} + +void object::add_reference() +{ + rcount += 1; +} + +void object::remove_reference() +{ + if (--rcount == 0) + delete this; +} + +object_dictionary::object_dictionary(int n) : d(n) +{ +} + +object *object_dictionary::lookup(symbol nm) +{ + return (object *)d.lookup(nm); +} + +void object_dictionary::define(symbol nm, object *obj) +{ + obj->add_reference(); + obj = (object *)d.lookup(nm, obj); + if (obj) + obj->remove_reference(); +} + +void object_dictionary::rename(symbol oldnm, symbol newnm) +{ + object *obj = (object *)d.remove(oldnm); + if (obj) { + obj = (object *)d.lookup(newnm, obj); + if (obj) + obj->remove_reference(); + } +} + +void object_dictionary::remove(symbol nm) +{ + object *obj = (object *)d.remove(nm); + if (obj) + obj->remove_reference(); +} + +// Return non-zero if oldnm was defined. + +int object_dictionary::alias(symbol newnm, symbol oldnm) +{ + object *obj = (object *)d.lookup(oldnm); + if (obj) { + obj->add_reference(); + obj = (object *)d.lookup(newnm, obj); + if (obj) + obj->remove_reference(); + return 1; + } + return 0; +} + |
