// © 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(void) const {return elementAt(0);}

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

    inline int32_t lastElementi(void) 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(void) const {return count;}

    inline UBool isEmpty(void) 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 NULL.

     */

    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(void) const {return isEmpty();}

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

    inline int32_t peeki(void) 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(void);

    int32_t popi(void);

    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