CMAP under vs2005+

From:
Tommy <tommy767@gmail.com>
Newsgroups:
microsoft.public.vc.language
Date:
Wed, 22 Oct 2008 21:53:51 -0400
Message-ID:
<#XGVnJLNJHA.5060@TK2MSFTNGP02.phx.gbl>
This is a multi-part message in MIME format.
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Hi,

Under VC6, I had a wrapper CMAP template, which I called CMapEx which
I used for many years as a way to map case insensitive key strings to
objects.

In other words, using an example with the traditional CMap class
collection:

     CMap<CString, const char *,CString, const char *> map;

     map["key1"] = "ext 2223";
     map["KEY1"] = "ext 2223";
     map["kEy2"] = "ext 2225";
     map["Key2"] = "ext 2225";

However, this is four unique keys. So CMapEx allowed me to do this in
a case insensitive manner:

     CMapEx<CString, const char *> map;

     map["key1"] = "ext 2223";
     map["KEY1"] = "ext 2223"; // Overrides first key1
     map["kEy2"] = "ext 2225";
     map["Key2"] = "ext 2225"; // Overrides first kEy2

There would be only two keys here.

CMapEx was been extremely valuable in my software compiled under VC6,
and now that I am moving to VS2005, of course, I am coming across some
afx template compatibility issues.

I guess I would like to ask if A) is it possible with a compiler
define or something that make afxtempl.h behavior the same? or B) is
there is a alternative approach, maybe using std c/c++ template that
will give me the same case insensitive collection behavior?

CMapEx (mapex.h) was designed using vc6.0 afxtempl.h as a starting
point and I attempted to migrated the vc8.0 afxtempl.h differences,
but the vc8 compiler is giving me template errors with the
implementation, i.e,, like with one of the assignments above. So
maybe I am expecting too much here and should probably CMapEx based on
afxtempl.h for a more reliable version not dependend on afxtempl.h.

If is possible to use CMap with an unique HashKey function unique to
CMapEx wrapper for CMAP so I can make the hash case insensitive?

Any tips?

I attached mapex.h. Maybe the changes necessary are more simple than I
know off hand.

--

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 filename="mapex.h"

//---------------------------------------------------------------------
// File : mapex.h
// About:
//
// A extended CMap template specifically for using case-insensitive
// string keys. No need to force the keys to one case. Any objects
// can be used for the map value parameter.
//
// Usage:
//
// CMapEx<VALUE, ARG_VALUE> object;
//
// Example:
//
// CMapEx<CString, const char *> map;
//
// map["key1"] = "ext 2223";
// map["KEY1"] = "ext 2223"; << overrides the first "key1"
// map["kEy2"] = "ext 2225";
// map["Key2"] = "ext 2225"; << override the first "kEy2"
//
// printf("count: %d\n",map.GetCount()); // SHOULD BE 2
//
//
// Reference:
//
// v:\vstudio\vc98\mfc\include\afx.h
// v:\vstudio\vc98\mfc\include\afxtempl.h
//
//---------------------------------------------------------------------

#ifndef __MAP_EX_H__
#define __MAP_EX_H__

#ifndef __AFXTEMPL_H__
    #include <afxtempl.h>
#endif

////////////////////////////////////////////////////////////////////
// CMapEx class uses the CMap template with string based keys.
//

#define TKEYSTR CString
#define TKEYARG LPCTSTR

template<class VALUE, class ARG_VALUE>
class CMapEx : public CMap<TKEYSTR, TKEYARG, VALUE, ARG_VALUE>
{
   typedef CMap inherited;
public:
    CMapEx(int nBlockSize = 10);
    CMapEx(const CMapEx &x);

private:
// new variables
   POSITION pos;
public:
// new function:
    BOOL First(TKEYSTR &key, VALUE &rValue)
    {
       pos = GetStartPosition();
       if (!pos) return FALSE;
       GetNextAssoc(pos, key, rValue);
       return TRUE;
    }

    BOOL Next(TKEYSTR &key, VALUE &rValue)
    {
       if (!pos) return FALSE;
       GetNextAssoc(pos, key, rValue);
       return TRUE;
    }

    DWORD GetSize() { return GetCount(); } // 451.2

// Overriding Public Members
public:

    void SetAt(TKEYARG key, ARG_VALUE newValue);
    VALUE& operator[](TKEYARG key);
    void GetNextAssoc(POSITION& rNextPosition, CString& rKey, VALUE& rValue) const;
    BOOL Lookup(TKEYARG key, VALUE& rValue) const;
    BOOL RemoveKey(TKEYARG key);

// Overriding Protected members
protected:
    CAssoc* NewAssoc();
    void FreeAssoc(CAssoc*);
    CAssoc* GetAssocAt(TKEYARG, UINT&) const;

// Private internal members
private:
    UINT HashString(TKEYARG key) const;
    BOOL CompareKeys(TKEYARG key1, TKEYARG key2) const;

// Protected internal members
protected:

};

//--------------------------------------------------------------------------

template<class VALUE, class ARG_VALUE>
inline CMapEx<VALUE, ARG_VALUE>::CMapEx(int nBlockSize)
    :CMap<TKEYSTR, TKEYARG, VALUE, ARG_VALUE>(nBlockSize)
{
    pos = NULL;
}

template<class VALUE, class ARG_VALUE>
inline CMapEx<VALUE, ARG_VALUE>::CMapEx(const CMapEx &x)
{
    *this = x;
    pos = NULL;
}

template<class VALUE, class ARG_VALUE>
AFX_INLINE void CMapEx<VALUE, ARG_VALUE>::SetAt(TKEYARG key, ARG_VALUE newValue)
{
    (*this)[key] = newValue;
}

template<class VALUE, class ARG_VALUE>
VALUE& CMapEx<VALUE, ARG_VALUE>::operator[](TKEYARG key)
{
    ASSERT_VALID(this);

    UINT nHash;
    CAssoc* pAssoc;
    if ((pAssoc = GetAssocAt(key, nHash)) == NULL)
    {
        if (m_pHashTable == NULL)
            InitHashTable(m_nHashTableSize);

        // it doesn't exist, add a new Association
        pAssoc = NewAssoc();
        pAssoc->nHashValue = nHash;
        pAssoc->key = key;
        // 'pAssoc->value' is a constructed object, nothing more

        // put into hash table
        pAssoc->pNext = m_pHashTable[nHash];
        m_pHashTable[nHash] = pAssoc;
    }
    return pAssoc->value; // return new reference
}

template<class VALUE, class ARG_VALUE>
CMapEx<VALUE, ARG_VALUE>::CAssoc*
CMapEx<VALUE, ARG_VALUE>::NewAssoc()
{
    if (m_pFreeList == NULL)
    {
        // add another block
        CPlex* newBlock = CPlex::Create(m_pBlocks, m_nBlockSize, sizeof(CMapEx::CAssoc));
        // chain them into free list
        CMapEx::CAssoc* pAssoc = (CMapEx::CAssoc*) newBlock->data();
        // free in reverse order to make it easier to debug
        pAssoc += m_nBlockSize - 1;
        for (int i = m_nBlockSize-1; i >= 0; i--, pAssoc--)
        {
            pAssoc->pNext = m_pFreeList;
            m_pFreeList = pAssoc;
        }
    }
    ASSERT(m_pFreeList != NULL); // we must have something

    CMapEx::CAssoc* pAssoc = m_pFreeList;
    m_pFreeList = m_pFreeList->pNext;
    m_nCount++;
    ASSERT(m_nCount > 0); // make sure we don't overflow
    ConstructElements(&pAssoc->key, 1);
    ConstructElements<VALUE>(&pAssoc->value, 1); // special construct values
    return pAssoc;
}

template<class VALUE, class ARG_VALUE>
void CMapEx<VALUE, ARG_VALUE>::FreeAssoc(CMapEx::CAssoc* pAssoc)
{
    DestructElements<VALUE>(&pAssoc->value, 1);
    DestructElements(&pAssoc->key, 1);
    pAssoc->pNext = m_pFreeList;
    m_pFreeList = pAssoc;
    m_nCount--;
    ASSERT(m_nCount >= 0); // make sure we don't underflow

    // if no more elements, cleanup completely
    if (m_nCount == 0)
        RemoveAll();
}

template<class VALUE, class ARG_VALUE>
CMapEx<VALUE, ARG_VALUE>::CAssoc*
CMapEx<VALUE, ARG_VALUE>::GetAssocAt(TKEYARG key, UINT& nHash) const

{
    nHash = HashString(key) % m_nHashTableSize;

    if (m_pHashTable == 0) return 0;

    CAssoc* pAssoc;
    for (pAssoc = m_pHashTable[nHash]; pAssoc != 0; pAssoc = pAssoc->pNext)
    {
        if (CompareKeys(pAssoc->key, key))
            return pAssoc;
    }
    return 0;
}

template<class VALUE, class ARG_VALUE>
BOOL CMapEx<VALUE, ARG_VALUE>::Lookup(TKEYARG key, VALUE& rValue) const
{

    ASSERT_VALID(this);

    UINT nHash;
    CAssoc* pAssoc = GetAssocAt(key, nHash);
    if (pAssoc == NULL)
        return FALSE; // not in map

    rValue = pAssoc->value;
    return TRUE;
}

template<class VALUE, class ARG_VALUE>
BOOL CMapEx<VALUE, ARG_VALUE>::RemoveKey(TKEYARG key)
// remove key - return TRUE if removed
{

    ASSERT_VALID(this);

    if (m_pHashTable == NULL)
        return FALSE; // nothing in the table

    CAssoc** ppAssocPrev;
    ppAssocPrev = &m_pHashTable[HashString(key) % m_nHashTableSize];

    CAssoc* pAssoc;
    for (pAssoc = *ppAssocPrev; pAssoc != NULL; pAssoc = pAssoc->pNext)
    {
        if (CompareKeys(pAssoc->key, key))
        {
            // remove it
            *ppAssocPrev = pAssoc->pNext; // remove from list
            FreeAssoc(pAssoc);
            return TRUE;
        }
        ppAssocPrev = &pAssoc->pNext;
    }
    return FALSE; // not found
}

template<class VALUE, class ARG_VALUE>
void CMapEx<VALUE, ARG_VALUE>::GetNextAssoc(POSITION& rNextPosition,
     CString& rKey, VALUE& rValue) const
{
    ASSERT_VALID(this);
    ASSERT(m_pHashTable != NULL); // never call on empty map

    CAssoc* pAssocRet = (CAssoc*)rNextPosition;
    ASSERT(pAssocRet != NULL);

    if (pAssocRet == (CAssoc*) BEFORE_START_POSITION)
    {
        // find the first association
        for (UINT nBucket = 0; nBucket < m_nHashTableSize; nBucket++)
            if ((pAssocRet = m_pHashTable[nBucket]) != NULL)
                break;
        ASSERT(pAssocRet != NULL); // must find something
    }

    // find next association
    ASSERT(AfxIsValidAddress(pAssocRet, sizeof(CAssoc)));
    CAssoc* pAssocNext;
    if ((pAssocNext = pAssocRet->pNext) == NULL)
    {
        // go to next bucket
        for (UINT nBucket = pAssocRet->nHashValue + 1;
          nBucket < m_nHashTableSize; nBucket++)
            if ((pAssocNext = m_pHashTable[nBucket]) != NULL)
                break;
    }

    rNextPosition = (POSITION) pAssocNext;

    // fill in return data
    rKey = pAssocRet->key;
    rValue = pAssocRet->value;
}

template<class VALUE, class ARG_VALUE>
AFX_INLINE UINT CMapEx<VALUE, ARG_VALUE>::HashString(TKEYARG Key) const
{
    LPCSTR key = Key;
    UINT nHash = 0;
    while (*key) {
      nHash = (nHash<<5) + nHash + towlower(*key++);
    }
    return nHash;
}

template<class VALUE, class ARG_VALUE>
AFX_INLINE BOOL CMapEx<VALUE, ARG_VALUE>::CompareKeys(TKEYARG key1, TKEYARG key2) const
{
    return stricmp(key1,key2) == 0;
}

//------------------------------------------------------------------------

typedef CMapEx<BOOL, BOOL> CMapBoolEx;
typedef CMapEx<DWORD, DWORD> CMapDWordEx;
typedef CMapEx<CString, const char *> CMapStringEx;

#endif

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