more TDB

source/libs/tdb/src/db/tdbBtree.c

@@ -690,7 +690,6 @@ static int tdbBtreeBalanceNonRoot(SBTree *pBt, SPage *pParent, int idx) {
   int nNews = 0;
   int cntNews[5] = {0};  // TODO: maybe 5 is not enough
   int szNews[5] = {0};
-  int maxPageCapacity;  // TODO
 
   {  // Get how many new pages are needed and the new distribution
 
@@ -699,11 +698,12 @@ static int tdbBtreeBalanceNonRoot(SBTree *pBt, SPage *pParent, int idx) {
       SPage *pPage = pOlds[i];
       SCell *pCell;
       int    cellBytes;
+
       for (int cIdx = 0; cIdx < TDB_PAGE_TOTAL_CELLS(pPage); cIdx++) {
         pCell = tdbPageGetCell(pPage, cIdx);
         cellBytes = TDB_BYTES_CELL_TAKEN(pPage, pCell);
 
-        if (szNews[nNews] + cellBytes > maxPageCapacity) {
+        if (szNews[nNews] + cellBytes > TDB_PAGE_USABLE_SIZE(pPage)) {
           nNews++;
         }
         cntNews[nNews]++;

source/libs/tdb/src/inc/tdbPage.h

@@ -99,6 +99,7 @@ struct SPage {
 
 // APIs
 #define TDB_PAGE_TOTAL_CELLS(pPage)        ((pPage)->nOverflow + (pPage)->pPageMethods->getCellNum(pPage))
+#define TDB_PAGE_USABLE_SIZE(pPage)        ((u8 *)(pPage)->pPageFtr - (pPage)->pCellIdx)
 #define TDB_BYTES_CELL_TAKEN(pPage, pCell) ((*(pPage)->xCellSize)(pPage, pCell) + (pPage)->pPageMethods->szOffset)
 
 int  tdbPageCreate(int pageSize, SPage **ppPage, void *(*xMalloc)(void *, size_t), void *arg);