tor-browser

uvector.h (12954B)

---

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
**********************************************************************
*   Copyright (C) 1999-2016, International Business Machines
*   Corporation 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"
#include "unicode/uobject.h"
#include "cmemory.h"
#include "uarrsort.h"
#include "uelement.h"

U_NAMESPACE_BEGIN

/**
* Ultralightweight C++ implementation of a `void*` vector
* that is (mostly) compatible with java.util.Vector.
*
* 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.
*
* *Design notes*
*
* 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 *do* avoid indexing off into the weeds.
*
* Since we don't have garbage collection, UVector was given the
* option to *own* 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.
*
* *Error Handling* Functions that can fail, from out of memory conditions
* for example, include a UErrorCode parameter. Any function called
* with an error code already indicating a failure will not modify the
* vector in any way.
*
* For vectors that have a deleter function, any failure in inserting
* an element into the vector will instead delete the element that
* could not be adopted. This simplifies object ownership
* management around calls to `addElement()` and `insertElementAt()`;
* error or no, the function always takes ownership of an incoming object
* from the caller.
*
* 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 function, 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 UObject {
   // NOTE: UVector uses the UElement (union of void* and int32_t) as
   // its basic storage type.  It uses UElementsAreEqual as its
   // comparison function.  It uses UObjectDeleter as its deleter
   // function.  This allows sharing of support functions with UHashtable.

private:
   int32_t count = 0;

   int32_t capacity = 0;

   UElement* elements = nullptr;

   UObjectDeleter *deleter = nullptr;

   UElementsAreEqual *comparer = nullptr;

public:
   UVector(UErrorCode &status);

   UVector(int32_t initialCapacity, UErrorCode &status);

   UVector(UObjectDeleter *d, UElementsAreEqual *c, UErrorCode &status);

   UVector(UObjectDeleter *d, UElementsAreEqual *c, int32_t initialCapacity, UErrorCode &status);

   virtual ~UVector();

   /**
    * Assign this object to another (make this a copy of 'other').
    * Use the 'assign' function to assign each element.
    */
   void assign(const UVector& other, UElementAssigner *assign, UErrorCode &ec);

   /**
    * Compare this vector with another.  They will be considered
    * equal if they are of the same size and all elements are equal,
    * as compared using this object's comparer.
    */
   bool operator==(const UVector& other) const;

   /**
    * Equivalent to !operator==()
    */
   inline bool operator!=(const UVector& other) const {return !operator==(other);}

   //------------------------------------------------------------
   // java.util.Vector API
   //------------------------------------------------------------

   /**
    * Add an element at the end of the vector.
    * For use only with vectors that do not adopt their elements, which is to say,
    * have not set an element deleter function. See `adoptElement()`.
    */
   void addElement(void *obj, UErrorCode &status);

   /**
    * Add an element at the end of the vector.
    * For use only with vectors that adopt their elements, which is to say,
    * have set an element deleter function. See `addElement()`.
    *
    * If the element cannot be successfully added, it will be deleted. This is
    * normal ICU _adopt_ behavior - one way or another ownership of the incoming
    * object is transferred from the caller.
    *
    * `addElement()` and `adoptElement()` are separate functions to make it easier
    * to see what the function is doing at call sites. Having a single combined function,
    * as in earlier versions of UVector, had proved to be error-prone.
    */
   void adoptElement(void *obj, UErrorCode &status);

   void addElement(int32_t elem, UErrorCode &status);

   void setElementAt(void* obj, int32_t index);

   void setElementAt(int32_t elem, int32_t index);

   void insertElementAt(void* obj, int32_t index, UErrorCode &status);

   void insertElementAt(int32_t elem, int32_t index, UErrorCode &status);
   
   void* elementAt(int32_t index) const;

   int32_t elementAti(int32_t index) const;

   UBool equals(const UVector &other) const;

   inline void* firstElement() const {return elementAt(0);}

   inline void* lastElement() const {return elementAt(count-1);}

   inline int32_t lastElementi() const {return elementAti(count-1);}

   int32_t indexOf(void* obj, int32_t startIndex = 0) const;

   int32_t indexOf(int32_t obj, int32_t startIndex = 0) const;

   inline UBool contains(void* obj) const {return indexOf(obj) >= 0;}

   inline UBool contains(int32_t obj) const {return indexOf(obj) >= 0;}

   UBool containsAll(const UVector& other) const;

   UBool removeAll(const UVector& other);

   UBool retainAll(const UVector& other);

   void removeElementAt(int32_t index);

   UBool removeElement(void* obj);

   void removeAllElements();

   inline int32_t size() const {return count;}

   inline UBool isEmpty() const {return count == 0;}

   UBool ensureCapacity(int32_t minimumCapacity, UErrorCode &status);

   /**
    * Change the size of this vector as follows: If newSize is
    * smaller, then truncate the array, possibly deleting held
    * elements for i >= newSize.  If newSize is larger, grow the
    * array, filling in new slots with nullptr.
    */
   void setSize(int32_t newSize, UErrorCode &status);

   /**
    * Fill in the given array with all elements of this vector.
    */
   void** toArray(void** result) const;

   //------------------------------------------------------------
   // New API
   //------------------------------------------------------------

   UObjectDeleter *setDeleter(UObjectDeleter *d);
   bool hasDeleter() {return deleter != nullptr;}

   UElementsAreEqual *setComparer(UElementsAreEqual *c);

   inline void* operator[](int32_t index) const {return elementAt(index);}

   /**
    * 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);

   /**
    * Returns true if this vector contains none of the elements
    * of the given vector.
    * @param other vector to be checked for containment
    * @return true if the test condition is met
    */
   UBool containsNone(const UVector& other) const;

   /**
    * Insert the given object into this vector at its sorted position
    * as defined by 'compare'.  The current elements are assumed to
    * be sorted already.
    */
   void sortedInsert(void* obj, UElementComparator *compare, UErrorCode& ec);

   /**
    * Insert the given integer into this vector at its sorted position
    * as defined by 'compare'.  The current elements are assumed to
    * be sorted already.
    */
   void sortedInsert(int32_t obj, UElementComparator *compare, UErrorCode& ec);

   /**
    * Sort the contents of the vector, assuming that the contents of the
    * vector are of type int32_t.
    */
   void sorti(UErrorCode &ec);

   /**
     * Sort the contents of this vector, using a caller-supplied function
     * to do the comparisons.  (It's confusing that
     *  UVector's UElementComparator function is different from the
     *  UComparator function type defined in uarrsort.h)
     */
   void sort(UElementComparator *compare, UErrorCode &ec);

   /**
    * Stable sort the contents of this vector using a caller-supplied function
    * of type UComparator to do the comparison.  Provides more flexibility
    * than UVector::sort() because an additional user parameter can be passed to
    * the comparison function.
    */
   void sortWithUComparator(UComparator *compare, const void *context, UErrorCode &ec);

   /**
    * ICU "poor man's RTTI", returns a UClassID for this class.
    */
   static UClassID U_EXPORT2 getStaticClassID();

   /**
    * ICU "poor man's RTTI", returns a UClassID for the actual class.
    */
   virtual UClassID getDynamicClassID() const override;

private:
   int32_t indexOf(UElement key, int32_t startIndex = 0, int8_t hint = 0) const;

   void sortedInsert(UElement e, UElementComparator *compare, UErrorCode& ec);

public:
   // Disallow
   UVector(const UVector&) = delete;

   // Disallow
   UVector& operator=(const UVector&) = delete;

};


/**
* Ultralightweight C++ implementation of a `void*` 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.
*
* *Design notes*
*
* The element at index `n-1` is (of course) the top of the
* stack.
*
* The poorly named `empty()` 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(UErrorCode &status);

   UStack(int32_t initialCapacity, UErrorCode &status);

   UStack(UObjectDeleter *d, UElementsAreEqual *c, UErrorCode &status);

   UStack(UObjectDeleter *d, UElementsAreEqual *c, int32_t initialCapacity, UErrorCode &status);

   virtual ~UStack();

   // It's okay not to have a virtual destructor (in UVector)
   // because UStack has no special cleanup to do.

   inline UBool empty() const {return isEmpty();}

   inline void* peek() const {return lastElement();}

   inline int32_t peeki() const {return lastElementi();}
   
   /**
    * Pop and return an element from the stack.
    * For stacks with a deleter function, the caller takes ownership
    * of the popped element.
    */
   void* pop();
   
   int32_t popi();
   
   inline void* push(void* obj, UErrorCode &status) {
       if (hasDeleter()) {
           adoptElement(obj, status);
           return (U_SUCCESS(status)) ? obj : nullptr;
       } else {
           addElement(obj, status);
           return obj;
       }
   }

   inline int32_t push(int32_t i, UErrorCode &status) {
       addElement(i, status);
       return i;
   }

   /*
   If the object o occurs as an item in this stack,
   this method returns the 1-based distance from the top of the stack.
   */
   int32_t search(void* obj) const;

   /**
    * ICU "poor man's RTTI", returns a UClassID for this class.
    */
   static UClassID U_EXPORT2 getStaticClassID();

   /**
    * ICU "poor man's RTTI", returns a UClassID for the actual class.
    */
   virtual UClassID getDynamicClassID() const override;

   // Disallow
   UStack(const UStack&) = delete;

   // Disallow
   UStack& operator=(const UStack&) = delete;
};

U_NAMESPACE_END

#endif