// This may look like C code, but it is really -*- C++ -*- /* Copyright (C) 1988 Free Software Foundation written by Doug Lea (dl@rocky.oswego.edu) This file is part of GNU CC. GNU CC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY. No author or distributor accepts responsibility to anyone for the consequences of using it or for whether it serves any particular purpose or works at all, unless he says so in writing. Refer to the GNU CC General Public License for full details. Everyone is granted permission to copy, modify and redistribute GNU CC, but only under the conditions described in the GNU CC General Public License. A copy of this license is supposed to have been given to you along with GNU CC so you can know your rights and responsibilities. It should be in a file named COPYING. Among other things, the copyright notice and this notice must be preserved on all copies. */ #ifdef __GNUG__ #pragma implementation #endif #include ".CHSet.h" // A CHSet is implemented as an array (tab) of buckets, each of which // contains a pointer to a list of CHNodes. Each node contains a // pointer to the next node in the list, and a pointer to the . // The end of the list is marked by a next node pointer which is odd // when considered as an integer (least significant bit = 1). The // assumption is that CHNodes will all begin on even addresses. If // the odd pointer is right-shifted by one bit, it becomes the index // within the tab array of the next bucket (that is, bucket i has // next bucket pointer 2*(i+1)+1). // The bucket pointers are initialized by the constructor and // used to support the next(Pix&) method. // This implementation is not portable to machines with different // pointer and integer sizes, or on which CHNodes might be aligned on // odd byte boundaries, but allows the same pointer to be used for // chaining within a bucket and to the next bucket. static inline int goodCHptr(CHNode* t) { return ((((unsigned)t) & 1) == 0); } static inline CHNode* index_to_CHptr(int i) { return (CHNode*)((i << 1) + 1); } static inline int CHptr_to_index(CHNode* t) { return ( ((unsigned) t) >> 1); } CHSet::CHSet(unsigned int sz) { tab = (CHNode**)(new CHNodePtr[size = sz]); for (unsigned int i = 0; i < size; ++i) tab[i] = index_to_CHptr(i+1); count = 0; } CHSet::CHSet(CHSet& a) { tab = (CHNode**)(new CHNodePtr[size = a.size]); for (unsigned int i = 0; i < size; ++i) tab[i] = index_to_CHptr(i+1); count = 0; for (Pix p = a.first(); p; a.next(p)) add(a(p)); } Pix CHSet::seek( key) { unsigned int h = HASH(key) % size; for (CHNode* t = tab[h]; goodCHptr(t); t = t->tl) if (EQ(key, t->hd)) return Pix(t); return 0; } Pix CHSet::add( item) { unsigned int h = HASH(item) % size; for (CHNode* t = tab[h]; goodCHptr(t); t = t->tl) if (EQ(item, t->hd)) return Pix(t); ++count; t = new CHNode(item, tab[h]); tab[h] = t; return Pix(t); } void CHSet::del( key) { unsigned int h = HASH(key) % size; CHNode* t = tab[h]; CHNode* trail = t; while (goodCHptr(t)) { if (EQ(key, t->hd)) { if (trail == t) tab[h] = t->tl; else trail->tl = t->tl; delete t; --count; return; } trail = t; t = t->tl; } } void CHSet::clear() { for (unsigned int i = 0; i < size; ++i) { CHNode* p = tab[i]; tab[i] = index_to_CHptr(i+1); while (goodCHptr(p)) { CHNode* nxt = p->tl; delete(p); p = nxt; } } count = 0; } Pix CHSet::first() { for (unsigned int i = 0; i < size; ++i) if (goodCHptr(tab[i])) return Pix(tab[i]); return 0; } void CHSet::next(Pix& p) { if (p == 0) return; CHNode* t = ((CHNode*)p)->tl; if (goodCHptr(t)) p = Pix(t); else { for (unsigned int i = CHptr_to_index(t); i < size; ++i) { if (goodCHptr(tab[i])) { p = Pix(tab[i]); return; } } p = 0; } } int CHSet::operator == (CHSet& b) { if (count != b.count) return 0; else { CHNode* p; for (unsigned int i = 0; i < size; ++i) for (p = tab[i]; goodCHptr(p); p = p->tl) if (b.seek(p->hd) == 0) return 0; for (i = 0; i < b.size; ++i) for (p = b.tab[i]; goodCHptr(p); p = p->tl) if (seek(p->hd) == 0) return 0; return 1; } } int CHSet::operator <= (CHSet& b) { if (count > b.count) return 0; else { for (unsigned int i = 0; i < size; ++i) for (CHNode* p = tab[i]; goodCHptr(p); p = p->tl) if (b.seek(p->hd) == 0) return 0; return 1; } } void CHSet::operator |= (CHSet& b) { if (&b == this || b.count == 0) return; for (unsigned int i = 0; i < b.size; ++i) for (CHNode* p = b.tab[i]; goodCHptr(p); p = p->tl) add(p->hd); } void CHSet::operator &= (CHSet& b) { for (unsigned int i = 0; i < size; ++i) { CHNode* t = tab[i]; CHNode* trail = t; while (goodCHptr(t)) { CHNode* nxt = t->tl; if (b.seek(t->hd) == 0) { if (trail == tab[i]) trail = tab[i] = nxt; else trail->tl = nxt; delete t; --count; } else trail = t; t = nxt; } } } void CHSet::operator -= (CHSet& b) { for (unsigned int i = 0; i < size; ++i) { CHNode* t = tab[i]; CHNode* trail = t; while (goodCHptr(t)) { CHNode* nxt = t->tl; if (b.seek(t->hd) != 0) { if (trail == tab[i]) trail = tab[i] = nxt; else trail->tl = nxt; delete t; --count; } else trail = t; t = nxt; } } } int CHSet::OK() { int v = tab != 0; int n = 0; for (unsigned int i = 0; i < size; ++i) { for (CHNode* p = tab[i]; goodCHptr(p); p = p->tl) ++n; v &= CHptr_to_index(p) == i + 1; } v &= count == n; if (!v) error("invariant failure"); return v; }