/*
 * Copyright 2001-2010, Haiku, Inc.
 * Distributed under the terms of the MIT License.
 */

#ifndef __TEXT_VIEW_SUPPORT_BUFFER__H__
#define __TEXT_VIEW_SUPPORT_BUFFER__H__

#include <cstdlib>
#include <cstring>

#include <OS.h>
#include <SupportDefs.h>


// _BTextViewSupportBuffer_ class ----------------------------------------------
template <class T>
class _BTextViewSupportBuffer_ {

public:
                                _BTextViewSupportBuffer_(int32 inExtraCount = 0, int32 inCount = 0);
virtual                 ~_BTextViewSupportBuffer_();

                void    InsertItemsAt(int32 inNumItems, int32 inAtIndex, const T* inItem);
                void    RemoveItemsAt(int32 inNumItems, int32 inAtIndex);

                int32   ItemCount() const;

protected:
                int32   fExtraCount;
                int32   fItemCount;
                int32   fBufferCount;
                T*              fBuffer;
};


template <class T>
_BTextViewSupportBuffer_<T>::_BTextViewSupportBuffer_(int32 inExtraCount,
                                                                                                          int32 inCount)
        :       fExtraCount(inExtraCount),
                fItemCount(inCount),
                fBufferCount(fExtraCount + fItemCount),
                fBuffer(NULL)
{
        fBuffer = (T*)calloc(fExtraCount + fItemCount, sizeof(T));
}


template <class T>
_BTextViewSupportBuffer_<T>::~_BTextViewSupportBuffer_()
{
        free(fBuffer);
}


template <class T>
void
_BTextViewSupportBuffer_<T>::InsertItemsAt(int32 inNumItems,
                                                                                                int32 inAtIndex,
                                                                                                const T* inItem)
{
        if (inNumItems < 1)
                return;

        inAtIndex = (inAtIndex > fItemCount) ? fItemCount : inAtIndex;
        inAtIndex = (inAtIndex < 0) ? 0 : inAtIndex;

        int32 delta = inNumItems * sizeof(T);
        int32 logSize = fItemCount * sizeof(T);
        if ((logSize + delta) >= fBufferCount) {
                fBufferCount = logSize + delta + (fExtraCount * sizeof(T));
                fBuffer = (T*)realloc((void*)fBuffer, fBufferCount);
                if (fBuffer == NULL)
                        debugger("InsertItemsAt(): reallocation failed");
        }

        T* loc = fBuffer + inAtIndex;
        memmove((void*)(loc + inNumItems), (void*)loc,
                (fItemCount - inAtIndex) * sizeof(T));
        memcpy((void*)loc, (void*)inItem, delta);

        fItemCount += inNumItems;
}


template <class T>
void
_BTextViewSupportBuffer_<T>::RemoveItemsAt(int32 inNumItems,
                                                                                                int32 inAtIndex)
{
        if (inNumItems < 1)
                return;

        inAtIndex = (inAtIndex > fItemCount - 1) ? (fItemCount - 1) : inAtIndex;
        inAtIndex = (inAtIndex < 0) ? 0 : inAtIndex;

        T* loc = fBuffer + inAtIndex;
        memmove(loc, loc + inNumItems,
                        (fItemCount - (inNumItems + inAtIndex)) * sizeof(T));

        int32 delta = inNumItems * sizeof(T);
        int32 logSize = fItemCount * sizeof(T);
        uint32 extraSize = fBufferCount - (logSize - delta);
        if (extraSize > (fExtraCount * sizeof(T))) {
                fBufferCount = (logSize - delta) + (fExtraCount * sizeof(T));
                fBuffer = (T*)realloc(fBuffer, fBufferCount);
                if (fBuffer == NULL)
                        debugger("RemoveItemsAt(): reallocation failed");
        }

        fItemCount -= inNumItems;
}


template<class T>
inline int32
_BTextViewSupportBuffer_<T>::ItemCount() const
{
        return fItemCount;
}


#endif // __TEXT_VIEW_SUPPORT_BUFFER__H__