/* coalesce free blocks */
static void *coalesce(void *bp){
size_t prevAllocBit = getPrevAlloc(getHeader(bp));
size_t nextAllocBit = getAlloc(getHeader(nextBlock(bp)));
size_t size = getSize(getHeader(bp));
size_t index;
size_t prevPAlloc;
/* both the previous and next block allocated */
if (prevAllocBit && nextAllocBit) {
setPrevFree(getHeader(nextBlock(bp)));
}
/* Only previous block is free */
else if (!prevAllocBit && nextAllocBit) {
size += getSize(getHeader(prevBlock(bp)));
prevPAlloc = getPrevAlloc(getHeader(prevBlock(bp)));
deleteListNode(prevBlock(bp));
put(getFooter(bp), size);
bp = prevBlock(bp);
put(getHeader(bp), pack(size, prevPAlloc, 0));
setPrevFree(getHeader(nextBlock(bp)));
}
/* Only next block is free */
else if (prevAllocBit && !nextAllocBit) {
size += getSize(getHeader(nextBlock(bp)));
deleteListNode(nextBlock(bp));
put(getHeader(bp), pack(size, prevAllocBit, 0));
put(getFooter(bp), size);
}
/* Both previous and next block are free */
else {
size += getSize(getHeader(prevBlock(bp))) +
getSize(getFooter(nextBlock(bp)));
prevPAlloc = getPrevAlloc(getHeader(prevBlock(bp)));
deleteListNode(nextBlock(bp));
deleteListNode(prevBlock(bp));
put(getHeader(prevBlock(bp)), pack(size, prevPAlloc, 0));
put(getFooter(nextBlock(bp)), size);
bp = prevBlock(bp);
}
index = getIndex(size);
insertListNode(bp, index);
return bp;
}
/* Place a block to bp. If bp is larger than asize by more than the minimum
block size, then split the block into two part, otherwize just set
the whole block allocated
*/
static void place(void *bp, size_t asize){
size_t csize = getSize(getHeader(bp));
size_t prevAllocBit = getPrevAlloc(getHeader(bp));
size_t index;
deleteListNode(bp);
// Split the block
if ((csize - asize) >= (2 * DSIZE)) {
// Allocate the first part
put(getHeader(bp), pack(asize, prevAllocBit, 1));
// Set the remaining part free
bp = nextBlock(bp);
put(getHeader(bp), pack((csize - asize), prevAllocBit, 0));
put(getFooter(bp), pack((csize - asize), 0, 0));
// Insert the free part into free list
index = getIndex(csize - asize);
insertListNode(bp, index);
}
// No split
else{
put(getHeader(bp), pack(csize, prevAllocBit, 1));
setPrevAlloc(getHeader(nextBlock(bp)));
}
}
ElemType pop(Stack * stack){
ElemType x = NULL;
ListNode * node;
if(stack->size > 0){
node = getFirst(stack->elem);
x = node->data;
deleteListNode(node);
stack->size--;
}
return x;
}