Utility中内存分配策略的示例分析

typedef unsigned int size_t;void *malloc(size_t nBytes);void *calloc(size_t elemNum, size_t elemSize);void *realloc(void *pBlock, size_t newSize);void free(void *ptr);

typedef int _Vx_STATUS;typedef _Vx_STATUS STATUS;STATUS cfree(char *pBlock);

void *memXxxAlloc    (    PART_ID  partId,  /* memory partition to allocate from */    unsigned nBytes,  /* number of bytes to allocate */    unsigned alignment/* boundary to align to */    ){    ...    DL_NODE *pNode = DLL_FIRST(&partId->freeList);    ...    while(pNode != NULL)        {        /* fits if:         *    - blocksize > requested size + extra room for alignment or,         *    - block is already aligned and exactly the right size         */        if ((NODE_TO_HDR (pNode)->nWords > nWordsExtra) ||            ((NODE_TO_HDR (pNode)->nWords == nWords) &&             (ALIGNED (HDR_TO_BLOCK(NODE_TO_HDR(pNode)), alignment))))            break;        pNode = DLL_NEXT (pNode);        }    ...    }

AVLU_NODE *avlXxxGet    (    AVLU_TREE root, /* root node pointer */    UINT      key   /* search key */    )    {    AVLU_NODE *pNode;    AVLU_NODE *pSuccessor;    pNode = root;    pSuccessor = NULL;    while (pNode != NULL)        {        if (key >= pNode->key)            {            pNode = pNode->right;            }        else            {            pSuccessor = pNode;            pNode = pNode->left;            }        }    return (pSuccessor);    }