/*
** Read a varint from the stream of data accessed by p. Set *pnOut to
** the value read.
*/
static int vdbeSorterIterVarint(sqlite3 *db, VdbeSorterIter *p, u64 *pnOut){
int iBuf;
iBuf = p->iReadOff % p->nBuffer;
if( iBuf && (p->nBuffer-iBuf)>=9 ){
p->iReadOff += sqlite3GetVarint(&p->aBuffer[iBuf], pnOut);
}else{
u8 aVarint[16], *a;
int i = 0, rc;
do{
rc = vdbeSorterIterRead(db, p, 1, &a);
if( rc ) return rc;
aVarint[(i++)&0xf] = a[0];
}while( (a[0]&0x80)!=0 );
sqlite3GetVarint(aVarint, pnOut);
}
return SQLITE_OK;
}
static int statDecodePage(Btree *pBt, StatPage *p){
int nUnused;
int iOff;
int nHdr;
int isLeaf;
int szPage;
u8 *aData = sqlite3PagerGetData(p->pPg);
u8 *aHdr = &aData[p->iPgno==1 ? 100 : 0];
p->flags = aHdr[0];
p->nCell = get2byte(&aHdr[3]);
p->nMxPayload = 0;
isLeaf = (p->flags==0x0A || p->flags==0x0D);
nHdr = 12 - isLeaf*4 + (p->iPgno==1)*100;
nUnused = get2byte(&aHdr[5]) - nHdr - 2*p->nCell;
nUnused += (int)aHdr[7];
iOff = get2byte(&aHdr[1]);
while( iOff ){
nUnused += get2byte(&aData[iOff+2]);
iOff = get2byte(&aData[iOff]);
}
p->nUnused = nUnused;
p->iRightChildPg = isLeaf ? 0 : sqlite3Get4byte(&aHdr[8]);
szPage = sqlite3BtreeGetPageSize(pBt);
if( p->nCell ){
int i; /* Used to iterate through cells */
int nUsable; /* Usable bytes per page */
sqlite3BtreeEnter(pBt);
nUsable = szPage - sqlite3BtreeGetReserveNoMutex(pBt);
sqlite3BtreeLeave(pBt);
p->aCell = sqlite3_malloc64((p->nCell+1) * sizeof(StatCell));
if( p->aCell==0 ) return SQLITE_NOMEM_BKPT;
memset(p->aCell, 0, (p->nCell+1) * sizeof(StatCell));
for(i=0; i<p->nCell; i++){
StatCell *pCell = &p->aCell[i];
iOff = get2byte(&aData[nHdr+i*2]);
if( !isLeaf ){
pCell->iChildPg = sqlite3Get4byte(&aData[iOff]);
iOff += 4;
}
if( p->flags==0x05 ){
/* A table interior node. nPayload==0. */
}else{
u32 nPayload; /* Bytes of payload total (local+overflow) */
int nLocal; /* Bytes of payload stored locally */
iOff += getVarint32(&aData[iOff], nPayload);
if( p->flags==0x0D ){
u64 dummy;
iOff += sqlite3GetVarint(&aData[iOff], &dummy);
}
if( nPayload>(u32)p->nMxPayload ) p->nMxPayload = nPayload;
getLocalPayload(nUsable, p->flags, nPayload, &nLocal);
pCell->nLocal = nLocal;
assert( nLocal>=0 );
assert( nPayload>=(u32)nLocal );
assert( nLocal<=(nUsable-35) );
if( nPayload>(u32)nLocal ){
int j;
int nOvfl = ((nPayload - nLocal) + nUsable-4 - 1) / (nUsable - 4);
pCell->nLastOvfl = (nPayload-nLocal) - (nOvfl-1) * (nUsable-4);
pCell->nOvfl = nOvfl;
pCell->aOvfl = sqlite3_malloc64(sizeof(u32)*nOvfl);
if( pCell->aOvfl==0 ) return SQLITE_NOMEM_BKPT;
pCell->aOvfl[0] = sqlite3Get4byte(&aData[iOff+nLocal]);
for(j=1; j<nOvfl; j++){
int rc;
u32 iPrev = pCell->aOvfl[j-1];
DbPage *pPg = 0;
rc = sqlite3PagerGet(sqlite3BtreePager(pBt), iPrev, &pPg, 0);
if( rc!=SQLITE_OK ){
assert( pPg==0 );
return rc;
}
pCell->aOvfl[j] = sqlite3Get4byte(sqlite3PagerGetData(pPg));
sqlite3PagerUnref(pPg);
}
}
}
}
}
return SQLITE_OK;
}
