You could save a few bytes in some sqlite internal structs if you'd
use C bitfields for boolean flags:
For example:
struct MemPage {
u8 isInit; /* True if previously initialized. MUST BE FIRST! */
u8 idxShift; /* True if Cell indices have changed */
u8 nOverflow; /* Number of overflow cell bodies in aCell[] */
u8 intKey; /* True if intkey flag is set */
u8 leaf; /* True if leaf flag is set */
u8 zeroData; /* True if table stores keys only */
u8 leafData; /* True if tables stores data on leaves only */
u8 hasData; /* True if this page stores data */
u8 hdrOffset; /* 100 for page 1. 0 otherwise */
u8 childPtrSize; /* 0 if leaf==1. 4 if leaf==0 */
u16 maxLocal; /* Copy of Btree.maxLocal or Btree.maxLeaf */
u16 minLocal; /* Copy of Btree.minLocal or Btree.minLeaf */
u16 cellOffset; /* Index in aData of first cell pointer */
u16 idxParent; /* Index in parent of this node */
u16 nFree; /* Number of free bytes on the page */
u16 nCell; /* Number of cells on this page, local and ovfl */
struct _OvflCell { /* Cells that will not fit on aData[] */
u8 *pCell; /* Pointers to the body of the overflow cell */
u16 idx; /* Insert this cell before idx-th non-overflow cell */
} aOvfl[5];
BtShared *pBt; /* Pointer back to BTree structure */
u8 *aData; /* Pointer back to the start of the page */
DbPage *pDbPage; /* Pager page handle */
Pgno pgno; /* Page number for this page */
MemPage *pParent; /* The parent of this page. NULL for root */
};
struct MemPage2 {
u8 nOverflow; /* Number of overflow cell bodies in aCell[] */
u8 childPtrSize; /* 0 if leaf==1. 4 if leaf==0 */
u8 hdrOffset; /* 100 for page 1. 0 otherwise */
u8 isInit:1; /* True if previously initialized. MUST BE FIRST! */
u8 idxShift:1; /* True if Cell indices have changed */
u8 intKey:1; /* True if intkey flag is set */
u8 leaf:1; /* True if leaf flag is set */
u8 zeroData:1; /* True if table stores keys only */
u8 leafData:1; /* True if tables stores data on leaves only */
u8 hasData:1; /* True if this page stores data */
u16 maxLocal; /* Copy of Btree.maxLocal or Btree.maxLeaf */
u16 minLocal; /* Copy of Btree.minLocal or Btree.minLeaf */
u16 cellOffset; /* Index in aData of first cell pointer */
u16 idxParent; /* Index in parent of this node */
u16 nFree; /* Number of free bytes on the page */
u16 nCell; /* Number of cells on this page, local and ovfl */
struct _OvflCell { /* Cells that will not fit on aData[] */
u8 *pCell; /* Pointers to the body of the overflow cell */
u16 idx; /* Insert this cell before idx-th non-overflow cell */
} aOvfl[5];
BtShared *pBt; /* Pointer back to BTree structure */
u8 *aData; /* Pointer back to the start of the page */
DbPage *pDbPage; /* Pager page handle */
Pgno pgno; /* Page number for this page */
MemPage *pParent; /* The parent of this page. NULL for root */
};
sizeof(struct MemPage) = 84
sizeof(struct MemPage2) = 76
Or is there a C portability issue?
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