|
浅析μC/GUI-v3.98之GUI_ALLOC_AllocZero()内存申请转句柄hWin函数
文章来源:http://gliethttp.cublog.cn
-------------------------------------------------------------------------------------
1.GUI_ALLOC_AllocZero()
gui/core/GUI_ALLOC_AllocZero.c
GUI_HMEM GUI_ALLOC_AllocZero(GUI_ALLOC_DATATYPE Size) {
GUI_HMEM hMem;
GUI_LOCK();
GUI_DEBUG_LOG2("\nGUI_ALLOC_Alloc... requesting %d, %d avail", Size, GUI_ALLOC_GetMaxSize());
hMem = GUI_ALLOC_AllocNoInit(Size); //申请size大小的内存空间,返回对该内存空间的目录索引
if (hMem) {
GUI_MEMSET((U8*)GUI_ALLOC_h2p(hMem), 0, Size); //填充0
}
GUI_UNLOCK();
return hMem;
}
-------------------------------------------------------------------------------------
2.GUI_ALLOC_AllocNoInit()函数
gui/core/GUIAlloc.c
GUI_HMEM GUI_ALLOC_AllocNoInit(GUI_ALLOC_DATATYPE Size) {
GUI_HMEM hMem;
if (Size == 0) {
return (GUI_HMEM)0;
}
GUI_LOCK();
GUI_DEBUG_LOG2("\nGUI_ALLOC_AllocNoInit... requesting %d, %d avail", Size, GUI_ALLOC.NumFreeBytes);
hMem = _Alloc(Size); //申请size大小的内存空间,返回对该内存空间的目录索引
GUI_DEBUG_LOG1("\nGUI_ALLOC_AllocNoInit : Handle", hMem);
GUI_UNLOCK();
return hMem;
}
-------------------------------------------------------------------------------------
3._Alloc()函数
gui/core/GUIAlloc.c
static GUI_HMEM _Alloc(GUI_ALLOC_DATATYPE size) {
GUI_HMEM hMemNew, hMemIns;
_CheckInit(); //检测GUI_ALLOC内存监控变量单元是否初始化,若未初始化,初始化之
size = _Size2LegalSize(size); //处理器字节对齐,可以是2字节,4字节
/* Check if memory is available at all ...*/
if (size > _GetNumFreeBytes()) { //返回空闲字节数GUI_ALLOC.NumFreeBytes
GUI_DEBUG_WARN1("GUI_ALLOC_Alloc: Insufficient memory configured (Trying to alloc % bytes)", size);
return 0;
}
/* Locate free handle */
if ((hMemNew = _FindFreeHandle()) == 0) { //2007-07-09 gliethttp申请内存空间的目录索引
return 0;
}
/* Locate or Create hole of sufficient size */
hMemIns = _FindHole(size); //查找紧邻的两个已用单元之间是否有size大小夹缝空间
#if GUI_ALLOC_AUTDEFRAG
if (hMemIns == -1) {
if (_LockCnt == 0) {
hMemIns = _CreateHole(size); //没有夹缝空间,创建全新的内存单元,同时整理内存碎片
}
}
#endif
/* Occupy hole */
if (hMemIns==-1) {
GUI_DEBUG_ERROROUT1("GUI_ALLOC_Alloc: Could not allocate %d bytes",size);
return 0;
}
{
GUI_ALLOC_DATATYPE Off = aBlock[hMemIns].Off + aBlock[hMemIns].Size;//空闲内存起始地址偏移量Off
int Next = aBlock[hMemIns].Next; //如果hMemIns是夹缝空间,那么将新单元hMemNew插入到hMemIns和hMemIns.Next之间
aBlock[hMemNew].Size = size;
aBlock[hMemNew].Off = Off;
if ((aBlock[hMemNew].Next = Next) >0) {
aBlock[Next].Prev = hMemNew; //如果hMemIns是夹缝空间,完善双向链表
}
aBlock[hMemNew].Prev = hMemIns;
aBlock[hMemIns].Next = hMemNew;
}
/* Keep track of number of blocks and av. memory */
GUI_ALLOC.NumUsedBlocks++; //内存维护变量单元的更新
GUI_ALLOC.NumFreeBlocks--;
if (GUI_ALLOC.NumFreeBlocksMin > GUI_ALLOC.NumFreeBlocks) {
GUI_ALLOC.NumFreeBlocksMin = GUI_ALLOC.NumFreeBlocks;
}
GUI_ALLOC.NumUsedBytes += size;
GUI_ALLOC.NumFreeBytes -= size;
if (GUI_ALLOC.NumFreeBytesMin > GUI_ALLOC.NumFreeBytes) {
GUI_ALLOC.NumFreeBytesMin = GUI_ALLOC.NumFreeBytes;
}
return hMemNew; //返回申请到的内存空间的目录索引
}
-------------------------------------------------------------------------------------
4._FindFreeHandle()函数
gui/core/GUIAlloc.c
static GUI_HMEM _FindFreeHandle(void) {
int i;
for (i = _FirstFreeHandle; i < GUI_MAXBLOCKS; i++) {
if (aBlock[i].Size == 0) {
_FirstFreeHandle = i; //申请内存空间的目录索引,aBlock[i].Size==0表示该目录空闲
return i;
}
}
GUI_DEBUG_ERROROUT1("Insufficient memory handles configured (GUI_MAXBLOCKS == %d (See GUIConf.h))", GUI_MAXBLOCKS);
return GUI_HMEM_NULL;
}
-------------------------------------------------------------------------------------
4._FindHole()函数
gui/core/GUIAlloc.c
static GUI_HMEM _FindHole(GUI_ALLOC_DATATYPE Size) {
int i, iNext;
for (i=0; (iNext = aBlock[i].Next) != 0; i = iNext) {
GUI_ALLOC_DATATYPE NumFreeBytes = aBlock[iNext].Off- (aBlock[i].Off+aBlock[i].Size);
if (NumFreeBytes>=Size) { //查找紧邻的两个已用单元之间是否有size大小空间
return i;
}
}
/* Check last block */
if (GUI_ALLOC_SIZE - (aBlock[i].Off+aBlock[i].Size) >= Size) {
return i;
}
return -1; //无
}
-------------------------------------------------------------------------------------
4._CreateHole()函数
gui/core/GUIAlloc.c
static GUI_HMEM _CreateHole(GUI_ALLOC_DATATYPE Size) {
int i, iNext;
int r = -1;
for (i=0; (iNext =aBlock[i].Next) !=0; i= iNext) { //创建全新的内存单元,同时整理内存碎片
GUI_ALLOC_DATATYPE NumFreeBytes = aBlock[iNext].Off- (aBlock[i].Off+aBlock[i].Size);
if (NumFreeBytes < Size) {
GUI_ALLOC_DATATYPE NumBytesBeforeBlock = aBlock[iNext].Off - (aBlock[i].Off+aBlock[i].Size);
if (NumBytesBeforeBlock) { //如果两个毗邻的内存块之间存在间隙,整理之
U8* pData = &GUI_Heap.abHeap[aBlock[iNext].Off];
memmove(pData-NumBytesBeforeBlock, pData, aBlock[iNext].Size);
aBlock[iNext].Off -=NumBytesBeforeBlock;
}
}
}
/* Check last block */
if (GUI_ALLOC_SIZE - (aBlock[i].Off+aBlock[i].Size) >= Size) {//没有超过内存上界,返回最后一个内存单元的目录索引,
r = i; //aBlock[r].Off+aBlock[r].Size即空闲内存的起始地址
}
return r;
}
|
