1// This may look like C code, but it is really -*- C++ -*- 2/* 3Copyright (C) 1988 Free Software Foundation 4 written by Doug Lea (dl@rocky.oswego.edu) 5 6This file is part of GNU CC. 7 8GNU CC is distributed in the hope that it will be useful, 9but WITHOUT ANY WARRANTY. No author or distributor 10accepts responsibility to anyone for the consequences of using it 11or for whether it serves any particular purpose or works at all, 12unless he says so in writing. Refer to the GNU CC General Public 13License for full details. 14 15Everyone is granted permission to copy, modify and redistribute 16GNU CC, but only under the conditions described in the 17GNU CC General Public License. A copy of this license is 18supposed to have been given to you along with GNU CC so you 19can know your rights and responsibilities. It should be in a 20file named COPYING. Among other things, the copyright notice 21and this notice must be preserved on all copies. 22*/ 23 24#ifdef __GNUG__ 25#pragma implementation 26#endif 27#include "<T>.<C>.VHMap.h" 28 29/* codes for status fields */ 30 31#define EMPTYCELL 0 32#define VALIDCELL 1 33#define DELETEDCELL 2 34 35 36<T><C>VHMap::<T><C>VHMap(<C&> dflt, unsigned int sz) 37 :<T><C>Map(dflt) 38{ 39 tab = new <T>[size = sz]; 40 cont = new <C>[size]; 41 status = new char[size]; 42 for (unsigned int i = 0; i < size; ++i) status[i] = EMPTYCELL; 43} 44 45<T><C>VHMap::<T><C>VHMap(<T><C>VHMap& a) : <T><C>Map(a.def) 46{ 47 tab = new <T>[size = a.size]; 48 cont = new <C>[size]; 49 status = new char[size]; 50 for (unsigned int i = 0; i < size; ++i) status[i] = EMPTYCELL; 51 count = 0; 52 for (Pix p = a.first(); p; a.next(p)) (*this)[a.key(p)] = a.contents(p); 53} 54 55 56/* 57 * hashing method: double hash based on high bits of hash fct, 58 * followed by linear probe. Can't do too much better if table 59 * sizes not constrained to be prime. 60*/ 61 62 63static inline unsigned int doublehashinc(unsigned int h, unsigned int s) 64{ 65 unsigned int dh = ((h / s) % s); 66 return (dh > 1)? dh : 1; 67} 68 69Pix <T><C>VHMap::seek(<T&> key) 70{ 71 unsigned int hashval = <T>HASH(key); 72 unsigned int h = hashval % size; 73 for (unsigned int i = 0; i <= size; ++i) 74 { 75 if (status[h] == EMPTYCELL) 76 return 0; 77 else if (status[h] == VALIDCELL && <T>EQ(key, tab[h])) 78 return Pix(&tab[h]); 79 if (i == 0) 80 h = (h + doublehashinc(hashval, size)) % size; 81 else if (++h >= size) 82 h -= size; 83 } 84 return 0; 85} 86 87 88<C>& <T><C>VHMap::operator [](<T&> item) 89{ 90 if (size <= count + 1) 91 resize(); 92 93 unsigned int bestspot = size; 94 unsigned int hashval = <T>HASH(item); 95 unsigned int h = hashval % size; 96 for (unsigned int i = 0; i <= size; ++i) 97 { 98 if (status[h] == EMPTYCELL) 99 { 100 ++count; 101 if (bestspot >= size) bestspot = h; 102 tab[bestspot] = item; 103 status[bestspot] = VALIDCELL; 104 cont[bestspot] = def; 105 return cont[bestspot]; 106 } 107 else if (status[h] == DELETEDCELL) 108 { 109 if (bestspot >= size) bestspot = h; 110 } 111 else if (<T>EQ(tab[h],item)) 112 return cont[h]; 113 114 if (i == 0) 115 h = (h + doublehashinc(hashval, size)) % size; 116 else if (++h >= size) 117 h -= size; 118 } 119 120 ++count; 121 status[bestspot] = VALIDCELL; 122 tab[bestspot] = item; 123 cont[bestspot] = def; 124 return cont[bestspot]; 125} 126 127 128void <T><C>VHMap::del(<T&> key) 129{ 130 unsigned int hashval = <T>HASH(key); 131 unsigned int h = hashval % size; 132 for (unsigned int i = 0; i <= size; ++i) 133 { 134 if (status[h] == EMPTYCELL) 135 return; 136 else if (status[h] == VALIDCELL && <T>EQ(key, tab[h])) 137 { 138 status[h] = DELETEDCELL; 139 --count; 140 return; 141 } 142 if (i == 0) 143 h = (h + doublehashinc(hashval, size)) % size; 144 else if (++h >= size) 145 h -= size; 146 } 147} 148 149 150void <T><C>VHMap::clear() 151{ 152 for (unsigned int i = 0; i < size; ++i) status[i] = EMPTYCELL; 153 count = 0; 154} 155 156void <T><C>VHMap::resize(unsigned int newsize) 157{ 158 if (newsize <= count) 159 { 160 newsize = DEFAULT_INITIAL_CAPACITY; 161 while (newsize <= count) newsize <<= 1; 162 } 163 <T>* oldtab = tab; 164 <C>* oldcont = cont; 165 char* oldstatus = status; 166 unsigned int oldsize = size; 167 tab = new <T>[size = newsize]; 168 cont = new <C>[size]; 169 status = new char[size]; 170 for (unsigned int i = 0; i < size; ++i) status[i] = EMPTYCELL; 171 count = 0; 172 for (i = 0; i < oldsize; ++i) 173 if (oldstatus[i] == VALIDCELL) 174 (*this)[oldtab[i]] = oldcont[i]; 175 delete [oldsize] oldtab; 176 delete [oldsize] oldcont; 177 delete oldstatus; 178} 179 180Pix <T><C>VHMap::first() 181{ 182 for (unsigned int pos = 0; pos < size; ++pos) 183 if (status[pos] == VALIDCELL) return Pix(&tab[pos]); 184 return 0; 185} 186 187void <T><C>VHMap::next(Pix& i) 188{ 189 if (i == 0) return; 190 unsigned int pos = ((unsigned)i - (unsigned)tab) / sizeof(<T>) + 1; 191 for (; pos < size; ++pos) 192 if (status[pos] == VALIDCELL) 193 { 194 i = Pix(&tab[pos]); 195 return; 196 } 197 i = 0; 198} 199 200 201int <T><C>VHMap::OK() 202{ 203 int v = tab != 0; 204 v &= status != 0; 205 int n = 0; 206 for (unsigned int i = 0; i < size; ++i) 207 { 208 if (status[i] == VALIDCELL) ++n; 209 else if (status[i] != DELETEDCELL && status[i] != EMPTYCELL) 210 v = 0; 211 } 212 v &= n == count; 213 if (!v) error("invariant failure"); 214 return v; 215} 216