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Diffstat (limited to 'src/context/cdcirclist.h')
-rw-r--r-- | src/context/cdcirclist.h | 418 |
1 files changed, 418 insertions, 0 deletions
diff --git a/src/context/cdcirclist.h b/src/context/cdcirclist.h new file mode 100644 index 000000000..cc6b60217 --- /dev/null +++ b/src/context/cdcirclist.h @@ -0,0 +1,418 @@ +/********************* */ +/*! \file cdcirclist.h + ** \verbatim + ** Original author: mdeters + ** Major contributors: none + ** Minor contributors (to current version): none + ** This file is part of the CVC4 prototype. + ** Copyright (c) 2009, 2010, 2011 The Analysis of Computer Systems Group (ACSys) + ** Courant Institute of Mathematical Sciences + ** New York University + ** See the file COPYING in the top-level source directory for licensing + ** information.\endverbatim + ** + ** \brief Context-dependent circular list class + ** + ** Context-dependent circular list class. + **/ + +#include "cvc4_private.h" + +#ifndef __CVC4__CONTEXT__CDCIRCLIST_H +#define __CVC4__CONTEXT__CDCIRCLIST_H + +#include <iterator> +#include <memory> +#include <string> +#include <sstream> + +#include "context/context.h" +#include "context/context_mm.h" +#include "context/cdcirclist_forward.h" +#include "context/cdo.h" +#include "util/Assert.h" + +namespace CVC4 { +namespace context { + +// CDO for pointers in particular, adds * and -> operators +template <class T> +class CDPtr : public CDO<T*> { + typedef CDO<T*> super; + + // private copy ctor + CDPtr(const CDPtr<T>& cdptr) : + super(cdptr) { + } + +public: + + CDPtr(Context* context, T* data = NULL) : + super(context, data) { + } + + CDPtr(bool allocatedInCMM, Context* context, T* data = NULL) : + super(allocatedInCMM, context, data) { + } + + // undesirable to put this here, since CDO<> does it already (?) + virtual ~CDPtr() throw(AssertionException) { this->destroy(); } + + virtual ContextObj* save(ContextMemoryManager* pCMM) { + Debug("context") << "save cdptr " << this << " (value " << super::get() << ")"; + ContextObj* p = new(pCMM) CDPtr<T>(*this); + Debug("context") << " to " << p << std::endl; + return p; + } + + virtual void restore(ContextObj* pContextObj) { + Debug("context") << "restore cdptr " << this << " (using " << pContextObj << ") from " << super::get(); + this->super::restore(pContextObj); + Debug("context") << " to " << super::get() << std::endl; + } + + CDPtr<T>& operator=(T* data) { + Debug("context") << "set " << this << " from " << super::get(); + super::set(data); + Debug("context") << " to " << super::get() << std::endl; + return *this; + } + // assignment is just like using the underlying ptr + CDPtr<T>& operator=(const CDPtr<T>& cdptr) { + return *this = cdptr.get(); + } + + T& operator*() { return *super::get(); } + T* operator->() { return super::get(); } + const T& operator*() const { return *super::get(); } + const T* operator->() const { return super::get(); } +};/* class CDPtr<T> */ + + +/** + * Class representing a single link in a CDCircList<>. + * + * The underlying T object is immutable, only the structure of the + * list is mutable, so only that's backtracked. + */ +template <class T, class AllocatorT> +class CDCircElement { + typedef CDCircElement<T, AllocatorT> elt_t; + const T d_t; + CDPtr<elt_t> d_prev; + CDPtr<elt_t> d_next; + friend class CDCircList<T, AllocatorT>; +public: + CDCircElement(Context* context, const T& t, + elt_t* prev = NULL, elt_t* next = NULL) : + d_t(t), + d_prev(true, context, prev), + d_next(true, context, next) { + } + + CDPtr<elt_t>& next() { return d_next; } + CDPtr<elt_t>& prev() { return d_prev; } + elt_t* next() const { return d_next; } + elt_t* prev() const { return d_prev; } + T element() const { return d_t; } +};/* class CDCircElement<> */ + + +/** + * Generic context-dependent circular list. Items themselves are not + * context dependent, only the forward and backward links. This + * allows two lists to be spliced together in constant time (see + * concat()). The list *structure* is mutable (things can be spliced + * in, removed, added, the list can be cleared, etc.) in a + * context-dependent manner, but the list items are immutable. To + * replace an item A in the list with B, A must be removed and + * B added in the same location. + */ +template <class T, class AllocatorT> +class CDCircList : public ContextObj { +public: + + /** List carrier element type */ + typedef CDCircElement<T, AllocatorT> elt_t; + /** The value type with which this CDCircList<> was instantiated. */ + typedef T value_type; + /** The allocator type with which this CDCircList<> was instantiated. */ + typedef AllocatorT Allocator; + +private: + + /** Head element of the circular list */ + CDPtr<elt_t> d_head; + /** The context with which we're associated */ + Context* d_context; + /** Our allocator */ + typename Allocator::template rebind< CDCircElement<T, AllocatorT> >::other d_allocator; + +public: + + CDCircList(Context* context, const Allocator& alloc = Allocator()) : + ContextObj(context), + d_head(context, NULL), + d_context(context), + d_allocator(alloc) { + } + + CDCircList(bool allocatedInCMM, Context* context, const Allocator& alloc = Allocator()) : + ContextObj(allocatedInCMM, context), + d_head(allocatedInCMM, context, NULL), + d_context(context), + d_allocator(alloc) { + Debug("cdcirclist") << "head " << &d_head << " in cmm ? " << allocatedInCMM << std::endl; + } + + ~CDCircList() throw(AssertionException) { + // by context contract, call destroy() here + destroy(); + } + + void clear() { + d_head = NULL; + } + + bool empty() const { + return d_head == NULL; + } + + CDPtr<elt_t>& head() { + return d_head; + } + + CDPtr<elt_t>& tail() { + return empty() ? d_head : d_head->d_prev; + } + + const elt_t* head() const { + return d_head; + } + + const elt_t* tail() const { + return empty() ? d_head : d_head->d_prev; + } + + T front() const { + Assert(! empty()); + return head()->element(); + } + + T back() const { + Assert(! empty()); + return tail()->element(); + } + + void push_back(const T& t) { + if(Debug.isOn("cdcirclist:paranoid")) { + debugCheck(); + } + // FIXME LEAK! (should alloc in CMM, no?) + elt_t* x = d_allocator.allocate(1); + if(empty()) { + // zero-element case + new(x) elt_t(d_context, t, x, x); + d_head = x; + } else { + // N-element case + new(x) elt_t(d_context, t, d_head->d_prev, d_head); + d_head->d_prev->d_next = x; + d_head->d_prev = x; + } + } + + /** + * Concatenate two lists. This modifies both: afterward, the two + * lists might have different heads, but they will have the same + * elements in the same (circular) order. + */ + void concat(CDCircList<T, AllocatorT>& l) { + Assert(this != &l, "cannot concat a list with itself"); + + if(d_head == NULL) { + d_head = l.d_head; + return; + } else if(l.d_head == NULL) { + l.d_head = d_head; + return; + } + + // splice together the two circular lists + CDPtr<elt_t> &l1head = head(), &l2head = l.head(); + CDPtr<elt_t> &l1tail = tail(), &l2tail = l.tail(); + // l2tail will change underneath us in what's below (because it's + // the same as l2head->prev()), so we have to keep a regular + // pointer to it + elt_t* oldl2tail = l2tail; + + Debug("cdcirclist") << "concat1 " << this << " " << &l << std::endl; + l1tail->next() = l2head; + Debug("cdcirclist") << "concat2" << std::endl; + l2head->prev() = l1tail; + + Debug("cdcirclist") << "concat3" << std::endl; + oldl2tail->next() = l1head; + Debug("cdcirclist") << "concat4" << std::endl; + l1head->prev() = oldl2tail; + Debug("cdcirclist") << "concat5" << std::endl; + } + + class iterator { + const CDCircList<T, AllocatorT>* d_list; + const elt_t* d_current; + friend class CDCircList<T, AllocatorT>; + public: + iterator(const CDCircList<T, AllocatorT>* list, const elt_t* first) : + d_list(list), + d_current(first) { + } + iterator(const iterator& other) : + d_list(other.d_list), + d_current(other.d_current) { + } + + bool operator==(const iterator& other) const { + return d_list == other.d_list && d_current == other.d_current; + } + bool operator!=(const iterator& other) const { + return !(*this == other); + } + iterator& operator++() { + Assert(d_current != NULL, "iterator already off the end"); + if(d_current == d_list->tail()) { + d_current = NULL; + } else { + d_current = d_current->next(); + } + return *this; + } + iterator operator++(int) { + const elt_t* old = d_current; + ++*this; + return iterator(d_list, old); + } + iterator& operator--() { + // undefined to go off the beginning, but don't have a check for that + if(d_current == NULL) { + d_current = d_list->tail(); + } else { + d_current = d_current->prev(); + } + return *this; + } + iterator operator--(int) { + const elt_t* old = d_current; + --*this; + return iterator(d_list, old); + } + T operator*() { + Assert(d_current != NULL, "iterator already off the end"); + return d_current->element(); + } + };/* class CDCircList<>::iterator */ + + // list elements are immutable + typedef iterator const_iterator; + + iterator begin() { + if(Debug.isOn("cdcirclist:paranoid")) { + debugCheck(); + } + return iterator(this, head()); + } + + iterator end() { + if(Debug.isOn("cdcirclist:paranoid")) { + debugCheck(); + } + return iterator(this, NULL); + } + + const_iterator begin() const { + return const_iterator(this, head()); + } + + const_iterator end() const { + return const_iterator(this, NULL); + } + + iterator erase(iterator pos) { + Assert(pos.d_current != NULL); + if(pos.d_current->prev() == pos.d_current) { + // one-elt list + d_head = NULL; + return iterator(this, NULL); + } else { + // N-elt list + if(pos.d_current == d_head) { + // removing list head + elt_t *pHead = head(), *pTail = tail(); + pTail->next() = pHead->next(); + pHead->next()->prev() = pTail; + d_head = pHead->next(); + return iterator(this, d_head); + // can't free old head, because of backtracking + } else { + // not removing list head + const elt_t *elt = pos.d_current; + elt_t *prev = pos.d_current->prev(); + prev->next() = elt->next(); + elt->next()->prev() = prev; + return iterator(this, elt->next()); + // can't free elt, because of backtracking + } + } + } + +private: + + // do not permit copy/assignment + CDCircList(const CDCircList<T, AllocatorT>&) CVC4_UNUSED; + CDCircList<T, AllocatorT>& operator=(const CDCircList<T, AllocatorT>&) CVC4_UNUSED; + +public: + /** Check internal structure and invariants of the list */ + void debugCheck() const { + elt_t* p = d_head; + Debug("cdcirclist") << "this is " << this << std::endl; + if(p == NULL) { + Debug("cdcirclist") << "head[" << &d_head << "] is NULL : " << d_context->getLevel() << std::endl; + // empty list + return; + } + Debug("cdcirclist") << "head[" << &d_head << "] is " << p << " next " << p->d_next << " prev " << p->d_prev << " : " << d_context->getLevel() << std::endl;//p->d_t << std::endl; + do { + elt_t* p_last = p; + p = p->d_next; + if(p == NULL) { + Debug("cdcirclist") << "****** ERROR ON LINE ABOVE, next == NULL ******" << std::endl; + break; + } + Debug("cdcirclist") << " p is " << p << " next " << p->d_next << " prev " << p->d_prev << " : " << std::endl;//p->d_t << std::endl; + if(p->d_prev != p_last) { + Debug("cdcirclist") << "****** ERROR ON LINE ABOVE, prev != last ******" << std::endl; + } + //Assert(p->d_prev == p_last); + Assert(p != NULL); + } while(p != d_head); + } + +private: + + // Nothing to save; the elements take care of themselves + virtual ContextObj* save(ContextMemoryManager* pCMM) { + Unreachable(); + } + + // Similarly, nothing to restore + virtual void restore(ContextObj* data) { + Unreachable(); + } + +};/* class CDCircList<> */ + +}/* CVC4::context namespace */ +}/* CVC4 namespace */ + +#endif /* __CVC4__CONTEXT__CDCIRCLIST_H */ |