An Image Decoder Based on IImgCtx

// DirMng.cpp
//

#include "stdafx.h"
#include "DirMng.h"
#include "SrchDir.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

CDirManager g_DirManager;

/////////////////////////////////////////////////////////////////////////////
// CDirManager

IMPLEMENT_DYNCREATE(CDirManager, CObject)

/////////////////////////////////////////////////////////////////////////////
// CDirManager construction/destruction

CDirManager::CDirManager()
{
	// TODO: add construction code here
	lstrcpy(m_szFiles, "*.jpg;*.jpeg;*.gif;*.bmp;*.dib;*.png;*.tif;*.tiff;*.wmf;*.emf;*.ico");
	m_uiTotalFilesInDir = 0;
	m_pInfoHeader = NULL;
	m_pCurrentInfo = NULL;
}

CDirManager::~CDirManager()
{
	ClearBuffer();
}

/////////////////////////////////////////////////////////////////////////////
// CDirManager diagnostics

#ifdef _DEBUG
void CDirManager::Dump(CDumpContext& dc) const
{
	CObject::Dump(dc);
}
#endif //_DEBUG

/////////////////////////////////////////////////////////////////////////////
// ͨ�ö��ּ����㷨, ����˵���μ�bsearch
// pHead: ������ָ��	pValue��Ҫ������ֵ
// lElements��������Ԫ�ظ���	iSize������Ԫ����ռ�ֽ���
// compare����������Ԫ�ش�С�Ļص�����
// ����ֵ���Ҳ���ʱ������ӽ���ֵ
void* FindEle(void* pHead, void* pValue,
					 long lElements, int iSize,
					 int (__cdecl* compare) (const void *, const void *))
{
	BYTE *pHigh, *pLow, *pMid;

	pLow = (BYTE*)pHead;
	pHigh = (BYTE*)pHead;
	pHigh += ((lElements-1)*iSize);

	while (pLow <= pHigh)
	{
		// �����۰�ָ��
		{
			unsigned long u = pHigh-pLow;
			u /= iSize;
			u /= 2;
			u *= iSize;
			pMid = pLow;
			pMid += u;
		}

		int iCalc = (*compare)((const void*)pValue, (const void*)pMid);

		if (iCalc < 0)
			pHigh = pMid - iSize;
		else if (iCalc > 0)
			pLow = pMid + iSize;
		else
			return (void*)pMid;
	}

	BYTE* pRet = max(pLow, pHigh);
	pRet = max((BYTE*)pHead, pRet);
	pRet = min(pRet, ((BYTE*)pHead)+((lElements-1)*iSize));
	return pRet;
}

/////////////////////////////////////////////////////////////////////////////

void CDirManager::ClearBuffer()
{
	m_uiTotalFilesInDir = 0;
	if (m_pInfoHeader)
	{
		delete [] m_pInfoHeader;
		m_pInfoHeader = NULL;
	}
}

void CDirManager::OpenDir(const char* pszDir)
{
	ClearBuffer();

	if (pszDir == NULL)
		return;
	if (*pszDir == '\0')
		return;

	{
		CDirCounter dircounter;
		m_uiTotalFilesInDir = dircounter.GetFilesInDir(pszDir, m_szFiles);
		m_pInfoHeader = new FILE_INFO[m_uiTotalFilesInDir];
	}
	if (m_pInfoHeader)
	{
		CDirInfo dirinfo;
		dirinfo.GetDirInfo(pszDir, m_szFiles, m_pInfoHeader);
	}
	else
		m_uiTotalFilesInDir = 0;

	Resort();
	m_pCurrentInfo = m_pInfoHeader;
}

void CDirManager::OpenFileInDir(const char* pszFile)
{
	char szDir[_MAX_PATH];
	char drive[_MAX_DRIVE];
	char dir[_MAX_DIR];

	if (pszFile && (*pszFile != '\0'))
	{
		_splitpath(pszFile, drive, dir, NULL, NULL);
		lstrcpy(szDir, drive);
		lstrcat(szDir, dir);

		OpenDir(szDir);
		AllocateFile(pszFile);
	}
}

const char* CDirManager::NextFile()
{
	BOOL bLastOne = FALSE;

	if (m_uiTotalFilesInDir == 0)
	{
		m_pCurrentInfo = NULL;
		MessageBeep(0xFFFFFFFF);
		bLastOne = TRUE;
	}
	else
	{
		m_pCurrentInfo++;
		if (m_pCurrentInfo >= (m_pInfoHeader + m_uiTotalFilesInDir))
		{
			if (m_uiTotalFilesInDir)
				m_pCurrentInfo = m_pInfoHeader + m_uiTotalFilesInDir - 1;
			MessageBeep(0xFFFFFFFF);
			bLastOne = TRUE;
		}
	}

	if (bLastOne) return NULL;

	if (m_pCurrentInfo == NULL)
		return NULL;

	return (const char*)m_pCurrentInfo->strFileName;
}

const char* CDirManager::PreFile()
{
	//if (m_pCurrentInfo == NULL) return NULL;
	//if (m_pInfoHeader == NULL) return NULL;

	BOOL bLastOne = FALSE;

	if (m_uiTotalFilesInDir == 0)
	{
		m_pCurrentInfo = NULL;
		MessageBeep(0xFFFFFFFF);
		bLastOne = TRUE;
	}
	else
	{
		m_pCurrentInfo--;
		if (m_pCurrentInfo < m_pInfoHeader)
		{
			m_pCurrentInfo = m_pInfoHeader;
			MessageBeep(0xFFFFFFFF);
			bLastOne = TRUE;
		}
	}

	if (bLastOne) return NULL;

	if (m_pCurrentInfo == NULL)
		return NULL;

	return (const char*)m_pCurrentInfo->strFileName;
}

const char* CDirManager::FirstFile()
{
	if (m_pCurrentInfo == NULL) return NULL;
	if (m_pInfoHeader == NULL) return NULL;
	if (m_uiTotalFilesInDir == 0) return NULL;
	m_pCurrentInfo = m_pInfoHeader;

	return (const char*)m_pCurrentInfo->strFileName;
}

const char* CDirManager::LastFile()
{
	if (m_pCurrentInfo == NULL) return NULL;
	if (m_pInfoHeader == NULL) return NULL;
	if (m_uiTotalFilesInDir == 0) return NULL;
	m_pCurrentInfo = m_pInfoHeader + m_uiTotalFilesInDir - 1;

	return (const char*)m_pCurrentInfo->strFileName;
}

void CDirManager::Resort()
{
	if (m_uiTotalFilesInDir)
		qsort((void*)m_pInfoHeader, m_uiTotalFilesInDir, sizeof(FILE_INFO), Compare);
}

void CDirManager::AllocateFile(const char* pszPath)
{
	if (m_pInfoHeader == NULL)
	{
		m_pCurrentInfo = NULL;
		return;
	}

	if (pszPath == NULL)
		return;
	if (*pszPath == '\0')
		return;

	FILE_INFO temp;
	temp.strFileName = pszPath;
	m_pCurrentInfo = (FILE_INFO*)FindEle((void*)m_pInfoHeader, (void*)&temp,
				 m_uiTotalFilesInDir, sizeof(FILE_INFO),Compare);
}

// ���򡢼�������ıȽϺ���
int CDirManager::Compare(const void *arg1, const void *arg2)
{
	int iRet = 0;

	FILE_INFO* p1 = (FILE_INFO*)arg1;
	FILE_INFO* p2 = (FILE_INFO*)arg2;
	return strcmpi(p1->strFileName, p2->strFileName);
}

int CDirManager::GetCurrentFileIndex()
{
	if (m_uiTotalFilesInDir == 0)
		return 0;

	return (m_pCurrentInfo - m_pInfoHeader + 1);
}

UINT CDirManager::TotalFilesInDir()
{
	return m_uiTotalFilesInDir;
}