[100分][新手问题] 帮我看看这段代码哪里发生了内存泄漏，刚学不懂。
HRGN BitmapToRegion(HBITMAP hBmp, COLORREF crTransparentColor, COLORREF crTolerance, const LPRECT prcSrounce)
{
HRGN hRgn = NULL;
if (hBmp)
{
// Create a memory DC inside which we will scan the bitmap content
HDC hMemDC = CreateCompatibleDC(NULL);
if (hMemDC)
{
// Get bitmap size
BITMAP bm;
GetObject(hBmp, sizeof(bm), &bm);
// Create a 32 bits depth bitmap and select it into the memory DC
BITMAPINFOHEADER RGB32BITSBITMAPINFO = {
sizeof(BITMAPINFOHEADER), // biSize
bm.bmWidth, // biWidth;
bm.bmHeight, // biHeight;
1, // biPlanes;
32, // biBitCount
BI_RGB, // biCompression;
0, // biSizeImage;
0, // biXPelsPerMeter;
0, // biYPelsPerMeter;
0, // biClrUsed;
0 // biClrImportant;
};
VOID * pbits32;
HBITMAP hbm32 = CreateDIBSection(hMemDC, (BITMAPINFO *)&RGB32BITSBITMAPINFO, DIB_RGB_COLORS, &pbits32, NULL, 0);
if (hbm32)
{
HBITMAP holdBmp = (HBITMAP)SelectObject(hMemDC, hbm32);
// Create a DC just to copy the bitmap into the memory DC
HDC hDC = CreateCompatibleDC(hMemDC);
if (hDC)
{
// Get how many bytes per row we have for the bitmap bits (rounded up to 32 bits)
BITMAP bm32;
GetObject(hbm32, sizeof(bm32), &bm32);
while (bm32.bmWidthBytes % 4)
bm32.bmWidthBytes++;
// Copy the bitmap into the memory DC
HBITMAP holdBmp = (HBITMAP)SelectObject(hDC, hBmp);
RECT rcSource; //
if(prcSrounce)
{
rcSource = *prcSrounce;
//
bm.bmWidth = prcSrounce-> right - prcSrounce-> left;
bm.bmHeight = prcSrounce-> bottom - prcSrounce-> top;
}
else
SetRect(&rcSource, 0, 0, bm.bmWidth, bm.bmHeight);
BitBlt(hMemDC, 0, 0, rcSource.right-rcSource.left, rcSource.bottom-rcSource.top, hDC, rcSource.left, rcSource.top, SRCCOPY);
#if 0
HDC hdc = ::GetDC(0);
BitBlt(hdc, 0, 0, rcSource.right-rcSource.left, rcSource.bottom-rcSource.top, hMemDC, 0, 0, SRCCOPY);
ReleaseDC(0, hdc);
#endif
// For better performances, we will use the ExtCreateRegion() function to create the
// region. This function take a RGNDATA structure on entry. We will add rectangles by
// amount of ALLOC_UNIT number in this structure.
#define ALLOC_UNIT 100
DWORD maxRects = ALLOC_UNIT;
HANDLE hData = GlobalAlloc(GMEM_MOVEABLE, sizeof(RGNDATAHEADER) + (sizeof(RECT) * maxRects)); ////// BoundsChecker报这行有内存泄漏
RGNDATA *pData = (RGNDATA *)GlobalLock(hData);
pData-> rdh.dwSize = sizeof(RGNDATAHEADER);
pData-> rdh.iType = RDH_RECTANGLES;
pData-> rdh.nCount = pData-> rdh.nRgnSize = 0;
SetRect(&pData-> rdh.rcBound, MAXLONG, MAXLONG, 0, 0);
// Keep on hand highest and lowest values for the "transparent " pixels
BYTE lr = GetRValue(crTransparentColor);
BYTE lg = GetGValue(crTransparentColor);
BYTE lb = GetBValue(crTransparentColor);
BYTE hr = min(0xff, lr + GetRValue(crTolerance));
BYTE hg = min(0xff, lg + GetGValue(crTolerance));
BYTE hb = min(0xff, lb + GetBValue(crTolerance));
// Scan each bitmap row from bottom to top (the bitmap is inverted vertically)
BYTE *p32 = (BYTE *)bm32.bmBits + (bm32.bmHeight - 1) * bm32.bmWidthBytes;
for (int y = 0; y < bm.bmHeight; y++)
{
// Scan each bitmap pixel from left to right
for (int x = 0; x < bm.bmWidth; x++)
{
// Search for a continuous range of "non transparent pixels "
int x0 = x;
LONG *p = (LONG *)p32 + x;
while (x < bm.bmWidth)
{
BYTE b = GetRValue(*p);
if (b > = lr && b <= hr)
{
b = GetGValue(*p);
if (b > = lg && b <= hg)
{
b = GetBValue(*p);
if (b > = lb && b <= hb)
// This pixel is "transparent "
break;
}
}
p++;
x++;
}
if (x > x0)
{
// Add the pixels (x0, y) to (x, y+1) as a new rectangle in the region
if (pData-> rdh.nCount > = maxRects)
{
GlobalUnlock(hData);
maxRects += ALLOC_UNIT;
hData = GlobalReAlloc(hData, sizeof(RGNDATAHEADER) + (sizeof(RECT) * maxRects), GMEM_MOVEABLE);
pData = (RGNDATA *)GlobalLock(hData);
}
RECT *pr = (RECT *)&pData-> Buffer;
SetRect(&pr[pData-> rdh.nCount], x0, y, x, y+1);
if (x0 < pData-> rdh.rcBound.left)
pData-> rdh.rcBound.left = x0;
if (y < pData-> rdh.rcBound.top)
pData-> rdh.rcBound.top = y;
if (x > pData-> rdh.rcBound.right)
pData-> rdh.rcBound.right = x;
if (y+1 > pData-> rdh.rcBound.bottom)
pData-> rdh.rcBound.bottom = y+1;
pData-> rdh.nCount++;
// On Windows98, ExtCreateRegion() may fail if the number of rectangles is too
// large (ie: > 4000). Therefore, we have to create the region by multiple steps.
if (pData-> rdh.nCount == 2000)
{
HRGN h = ExtCreateRegion(NULL, sizeof(RGNDATAHEADER) + (sizeof(RECT) * maxRects), pData);
if (hRgn)
{
CombineRgn(hRgn, hRgn, h, RGN_OR);
DeleteObject(h);
}
else
hRgn = h;
pData-> rdh.nCount = 0;
SetRect(&pData-> rdh.rcBound, MAXLONG, MAXLONG, 0, 0);
}
}
}
// Go to next row (remember, the bitmap is inverted vertically)
p32 -= bm32.bmWidthBytes;
}
// Create or extend the region with the remaining rectangles
HRGN h = ExtCreateRegion(NULL, sizeof(RGNDATAHEADER) + (sizeof(RECT) * maxRects), pData);
if (hRgn)
{
CombineRgn(hRgn, hRgn, h, RGN_OR);
DeleteObject(h);
}
else
hRgn = h;
// Clean up
::SelectObject(hDC, holdBmp);
::DeleteDC(hDC);
}
DeleteObject(SelectObject(hMemDC, holdBmp));
}
DeleteDC(hMemDC);
}
}
return hRgn;
}
-------------------------------------------------------
我用BoundsChecker检测，报HANDLE hData = GlobalAlloc(GMEM_MOVEABLE, sizeof(RGNDATAHEADER) + (sizeof(RECT) * maxRects));这句有内存泄漏。
帮忙看看！怎么解决。
[解决办法]
你要用GlobalFree将内存释放才行
[解决办法]
GlobalAlloc有一种情况下要用就是CreateStreamOnHGlobal
GlobalAlloc在Win16中就已经有了，这个函数返回一个句柄，通过这个句柄，两个进程可以共享一块内存
GlobalAlloc/GlobalFree
[解决办法]
呵呵，要先unlock，才能free
所以
GlobalUnlock(hData);
GlobalFree(hData);
[解决办法]
VOID * pbits32;
[解决办法]
恩
[解决办法]
bmBitmap是一个结构体，由于建立在栈上在函数执行完之后会自动释放
[解决办法]
没办法判断一个指针是否已经被释放了，所以要在释放指针后赋值为NULL，就是为了避免野指针，上面这种情况看来只能靠良好的编程习惯业解决了，在释放a时，也同时把b给赋值为NULL.
[解决办法]
mark
[解决办法]
好复杂啊
[解决办法]
这么麻烦