void coalesceIfNecessary(buffer* aBuffer) {
if (aBuffer->size == 8192) {
removeBufferFromFreeList(aBuffer, getFreeList(aBuffer->size));
if (debug) printf("Coalesced to max size\n");
freeListPointers* freeLists = (freeListPointers*)entryPoint->ptr;
pageHeaderInfo* pageHeader = (void*)aBuffer->start - sizeof(pageHeaderInfo);
if (debug) printf("The start is at %p and the page header is at %p\n", aBuffer->start, pageHeader);
free_page(pageHeader->pageInfo);
freeLists->numAllocatedPages--;
if (freeLists->numAllocatedPages == 0) {
free_page(entryPoint);
entryPoint = 0;
}
return;
}
buffer* buddy = getBuddy(aBuffer);
if (debug) printf("Trying to coalesce a buffer of size %i\n", aBuffer->size);
if (!buddy->isAllocated && buddy->size == aBuffer->size) {
freeListInfo* freeList = getFreeList(buddy->size);
removeBufferFromFreeList(buddy, freeList);
removeBufferFromFreeList(aBuffer, freeList);
buffer* parent = buddy < aBuffer ? buddy : aBuffer;
parent->size = parent->size*2;
addBufferToFreeList(parent, getFreeList(parent->size));
coalesceIfNecessary(parent);
}
}
void splitLargerList(int size) {
freeListInfo* freeList;
if (size != 8192) {
freeList = getFreeList(size*2);
freeListInfo* smallFreeList = getFreeList(size);
if (freeList->nextBuffer == 0) {
if (debug) printf("Splitting %i into %i\n", size*2, size);
splitLargerList(size*2);
}
splitLargeBufferToSmallBuffer(freeList, smallFreeList, size);
return;
}
freeList = getFreeList(size);
if (freeList->nextBuffer == 0) {
kpage_t* page = get_page();
freeListPointers* freeLists = (freeListPointers*)entryPoint->ptr;
freeLists->numAllocatedPages++;
pageHeaderInfo* pageHeader = (pageHeaderInfo*)page->ptr;
pageHeader->pageInfo = page;
pageHeader->nextPage = 0;
addPageToFreeList(pageHeader, freeList);
void* pageBegin = page->ptr + sizeof(pageHeaderInfo);
int numBuffers = (page->size - sizeof(pageHeaderInfo)) / size;
numBuffers = numBuffers == 0 ? 1 : numBuffers;
if (debug) printf("of size %i at %p with %i buffers\n", page->size, pageBegin, numBuffers);
int i;
buffer* aBuffer = 0;
for (i = 0; i < numBuffers; i++) {
aBuffer = (pageBegin + i * size);
if (debug) printf("Buffer %i starts at %p ", i + 1, aBuffer);
aBuffer->header = 0;
aBuffer->start = pageBegin;
aBuffer->isAllocated = 0;
aBuffer->size = size;
if (debug) printf("and points to %p\n", aBuffer->header);
addBufferToFreeList(aBuffer, freeList);
}
}
}
KeyPageAddr KeyFile::fetchNewPage(bool leafPage) {
KeyPageAddr addr;
KeyPage page(m_pageInfo);
KeyPageAddr freeList = getFreeList();
if(freeList == DB_NULLADDR) {
try {
addr = getLast() + 1;
page.init(leafPage);
writePage(addr, page);
setLast(addr);
} catch(sqlca) {
return DB_NULLADDR;
}
} else {
try {
addr = freeList;
readPage(freeList, page);
logPage( freeList, page);
freeList = page.getNextFree();
setFreeList(freeList,-1);
page.init(leafPage);
writePage(addr, page);
} catch(sqlca) {
return DB_NULLADDR;
}
}
return addr;
}
void*
kma_malloc(kma_size_t size)
{
if (debug) printf("\nREQUEST %i\n", size);
if (entryPoint == 0) {
entryPoint = getEntryPoint();
}
int adjustedSize = size + sizeof(buffer);
int bufferSize = getBufferSize(adjustedSize);
freeListInfo* freeList = getFreeList(bufferSize);
if (freeList == NULL) {
return NULL;
}
getSpaceIfNeeded(freeList, bufferSize);
return getNextBuffer(freeList);
}
void KeyFile::releasePage(KeyPageAddr addr) {
KeyPage page(m_pageInfo);
page.setNextFree(getFreeList());
writePage(addr, page);
setFreeList(addr,1);
}
