scuffed-code/icu4c/source/common/uvector.h

246 lines
6.9 KiB
C++

/*
**********************************************************************
* Copyright (C) 1999, International Business Machines
* Corporation and others. All Rights Reserved.
**********************************************************************
* Copyright (C) 1999 Alan Liu and others. All rights reserved.
**********************************************************************
* Date Name Description
* 10/22/99 alan Creation. This is an internal header.
* It should not be exported.
**********************************************************************
*/
#ifndef UVECTOR_H
#define UVECTOR_H
#include "unicode/utypes.h"
/**
* <p>Ultralightweight C++ implementation of a <tt>void*</tt> vector
* that is (mostly) compatible with java.util.Vector.
*
* <p>This is a very simple implementation, written to satisfy an
* immediate porting need. As such, it is not completely fleshed out,
* and it aims for simplicity and conformity. Nonetheless, it serves
* its purpose (porting code from java that uses java.util.Vector)
* well, and it could be easily made into a more robust vector class.
*
* <p><b>Design notes</b>
*
* <p>There is index bounds checking, but little is done about it. If
* indices are out of bounds, either nothing happens, or zero is
* returned. We <em>do</em> avoid indexing off into the weeds.
*
* <p>There is detection of out of memory, but the handling is very
* coarse-grained -- similar to UnicodeString's protocol, but even
* coarser. The class contains <em>one static flag</em> that is set
* when any call to <tt>new</tt> returns zero. This allows the caller
* to use several vectors and make just one check at the end to see if
* a memory failure occurred. This is more efficient than making a
* check after each call on each vector when doing many operations on
* multiple vectors. The single static flag works best when memory
* failures are infrequent, and when recovery options are limited or
* nonexistent.
*
* <p>Since we don't have garbage collection, UVector was given the
* option to <em>own</em>its contents. To employ this, set a deleter
* function. The deleter is called on a void* pointer when that
* pointer is released by the vector, either when the vector itself is
* destructed, or when a call to setElementAt() overwrites an element,
* or when a call to remove() or one of its variants explicitly
* removes an element. If no deleter is set, or the deleter is set to
* zero, then it is assumed that the caller will delete elements as
* needed.
*
* <p>In order to implement methods such as contains() and indexOf(),
* UVector needs a way to compare objects for equality. To do so, it
* uses a comparison frunction, or "comparer." If the comparer is not
* set, or is set to zero, then all such methods will act as if the
* vector contains no element. That is, indexOf() will always return
* -1, contains() will always return FALSE, etc.
*
* <p><b>To do</b>
*
* <p>Improve the handling of index out of bounds errors.
*
* @author Alan Liu
*/
class U_COMMON_API UVector {
public:
typedef void (*Deleter)(void*);
typedef bool_t (*Comparer)(void*, void*);
private:
int32_t count;
int32_t capacity;
void** elements;
Deleter deleter;
Comparer comparer;
static bool_t outOfMemory;
public:
UVector(int32_t initialCapacity = 8);
UVector(Deleter d, Comparer c, int32_t initialCapacity = 8);
~UVector();
//------------------------------------------------------------
// java.util.Vector API
//------------------------------------------------------------
void addElement(void* obj);
void setElementAt(void* obj, int32_t index);
void insertElementAt(void* obj, int32_t index);
void* elementAt(int32_t index) const;
void* firstElement(void) const;
void* lastElement(void) const;
int32_t indexOf(void* obj, int32_t startIndex = 0) const;
bool_t contains(void* obj) const;
void removeElementAt(int32_t index);
bool_t removeElement(void* obj);
void removeAllElements();
int32_t size(void) const;
bool_t isEmpty(void) const;
bool_t ensureCapacity(int32_t minimumCapacity);
//------------------------------------------------------------
// New API
//------------------------------------------------------------
Deleter setDeleter(Deleter d);
Comparer setComparer(Comparer c);
static bool_t isOutOfMemory(void);
void* operator[](int32_t index) const;
/**
* Removes the element at the given index from this vector and
* transfer ownership of it to the caller. After this call, the
* caller owns the result and must delete it and the vector entry
* at 'index' is removed, shifting all subsequent entries back by
* one index and shortening the size of the vector by one. If the
* index is out of range or if there is no item at the given index
* then 0 is returned and the vector is unchanged.
*/
void* orphanElementAt(int32_t index);
private:
void _init(int32_t initialCapacity);
// Disallow
UVector(const UVector&);
// Disallow
UVector& operator=(const UVector&);
};
/**
* <p>Ultralightweight C++ implementation of a <tt>void*</tt> stack
* that is (mostly) compatible with java.util.Stack. As in java, this
* is merely a paper thin layer around UVector. See the UVector
* documentation for further information.
*
* <p><b>Design notes</b>
*
* <p>The element at index <tt>n-1</tt> is (of course) the top of the
* stack.
*
* <p>The poorly named <tt>empty()</tt> method doesn't empty the
* stack; it determines if the stack is empty.
*
* @author Alan Liu
*/
class U_COMMON_API UStack : public UVector {
public:
UStack(int32_t initialCapacity = 8);
UStack(Deleter d, Comparer c, int32_t initialCapacity = 8);
// It's okay not to have a virtual destructor (in UVector)
// because UStack has no special cleanup to do.
bool_t empty(void) const;
void* peek(void) const;
void* pop(void);
void* push(void* obj);
int32_t search(void* obj) const;
private:
// Disallow
UStack(const UStack&);
// Disallow
UStack& operator=(const UStack&);
};
// UVector inlines
inline int32_t UVector::size(void) const {
return count;
}
inline bool_t UVector::isEmpty(void) const {
return count == 0;
}
inline bool_t UVector::contains(void* obj) const {
return indexOf(obj) >= 0;
}
inline void* UVector::firstElement(void) const {
return elementAt(0);
}
inline void* UVector::lastElement(void) const {
return elementAt(count-1);
}
inline void* UVector::operator[](int32_t index) const {
return elementAt(index);
}
// UStack inlines
inline bool_t UStack::empty(void) const {
return isEmpty();
}
inline void* UStack::peek(void) const {
return lastElement();
}
inline void* UStack::push(void* obj) {
addElement(obj);
return obj;
}
#endif