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The btree.c module compiles and links and passes some tests. Many tests

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still fail, though. (CVS 1321)

FossilOrigin-Name: d394b2b217d4d728f9eba397262bf9d36195719e
This commit is contained in:
drh
2004-05-07 17:57:49 +00:00
parent a34b676483
commit de64713041
8 changed files with 225 additions and 182 deletions
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110
src/btree.c
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@@ -9,7 +9,7 @@
** May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.110 2004/05/07 13:30:42 drh Exp $
** $Id: btree.c,v 1.111 2004/05/07 17:57:50 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
@@ -57,7 +57,7 @@
** of that header is as follows:
**
** OFFSET SIZE DESCRIPTION
** 0 16 Header string: "SQLite version 3"
** 0 16 Header string: "SQLite format 3\000"
** 16 2 Page size in bytes.
** 18 1 File format write version
** 19 1 File format read version
@@ -187,16 +187,16 @@ typedef struct MemPage MemPage;
/*
** This is a magic string that appears at the beginning of every
** SQLite database in order to identify the file as a real database.
** 0123456789 123456 */
static const char zMagicHeader[] = "SQLite version 3";
** 123456789 123456 */
static const char zMagicHeader[] = "SQLite format 3";
/*
** Page type flags. An ORed combination of these flags appear as the
** first byte of every BTree page.
*/
#define PTF_LEAF 0x01
#define PTF_INTKEY 0x01
#define PTF_ZERODATA 0x02
#define PTF_INTKEY 0x04
#define PTF_LEAF 0x04
/* Idea for the future: PTF_LEAFDATA */
/*
@@ -210,6 +210,7 @@ static const char zMagicHeader[] = "SQLite version 3";
** The pageDestructor() routine handles that chore.
*/
struct MemPage {
u32 notUsed;
struct Btree *pBt; /* Pointer back to BTree structure */
unsigned char *aData; /* Pointer back to the start of the page */
u8 isInit; /* True if previously initialized */
@@ -326,10 +327,10 @@ static unsigned int getVarint(unsigned char *p, u64 *pResult){
static unsigned int putVarint(unsigned char *p, u64 v){
int i = 0;
do{
p[i++] = v & 0x7f;
p[i++] = (v & 0x7f) | 0x80;
v >>= 7;
}while( v!=0 );
p[i-1] |= 0x80;
p[i-1] &= 0x7f;
return i;
}
@@ -354,7 +355,7 @@ static void parseCellHeader(
}else{
n += getVarint(&pCell[n], pnData);
}
n += getVarint(pCell, pnKey);
n += getVarint(&pCell[n], pnKey);
*pnHeader = n;
}
@@ -489,9 +490,10 @@ static int allocateSpace(MemPage *pPage, int nByte){
assert( pc>0 && size>=nByte );
assert( pc+size<=pPage->pBt->pageSize );
if( size>nByte+4 ){
put2byte(&data[addr], pc+nByte);
put2byte(&data[pc+size], get2byte(&data[pc]));
put2byte(&data[pc+size+2], size-nByte);
int newStart = pc+nByte;
put2byte(&data[addr], newStart);
put2byte(&data[newStart], get2byte(&data[pc]));
put2byte(&data[newStart+2], size-nByte);
}else{
put2byte(&data[addr], get2byte(&data[pc]));
data[hdr+5] += size-nByte;
@@ -691,7 +693,7 @@ static int initPage(
assert( pPage->pBt!=0 );
assert( pParent==0 || pParent->pBt==pPage->pBt );
assert( pPage->pgno==sqlite3pager_pagenumber(pPage->aData) );
assert( pPage->aData == &((unsigned char*)pPage)[pPage->pBt->pageSize] );
assert( pPage->aData == &((unsigned char*)pPage)[-pPage->pBt->pageSize] );
assert( pPage->isInit==0 || pPage->pParent==pParent );
if( pPage->isInit ) return SQLITE_OK;
assert( pPage->pParent==0 );
@@ -700,7 +702,8 @@ static int initPage(
sqlite3pager_ref(pParent->aData);
}
pPage->nCell = pPage->nCellAlloc = 0;
pPage->hdrOffset = hdr = pPage->pgno==1 ? 100 : 0;
assert( pPage->hdrOffset==(pPage->pgno==1 ? 100 : 0) );
hdr = pPage->hdrOffset;
data = pPage->aData;
c = data[hdr];
pPage->intKey = (c & PTF_INTKEY)!=0;
@@ -722,8 +725,8 @@ static int initPage(
pc = get2byte(&data[hdr+3]);
for(i=0; pc>0; i++){
pPage->aCell[i] = &data[pc];
pc = get2byte(&data[pc]);
sumCell += cellSize(pPage, &data[pc]);
pc = get2byte(&data[pc]);
}
/* Compute the total free space on the page */
@@ -746,6 +749,7 @@ static int initPage(
return SQLITE_CORRUPT;
}
pPage->isInit = 1;
return SQLITE_OK;
}
@@ -762,12 +766,13 @@ static void zeroPage(MemPage *pPage, int flags){
assert( sqlite3pager_iswriteable(data) );
memset(&data[hdr], 0, pBt->pageSize - hdr);
data[hdr] = flags;
first = hdr + 6 + 4*((flags&0x01)!=0);
first = hdr + 6 + 4*((flags&PTF_LEAF)==0);
put2byte(&data[hdr+1], first);
put2byte(&data[first+2], pBt->pageSize - first);
sqliteFree(pPage->aCell);
pPage->aCell = 0;
pPage->nCell = 0;
pPage->nCellAlloc = 0;
pPage->nFree = pBt->pageSize - first;
pPage->intKey = (flags & PTF_INTKEY)!=0;
pPage->leaf = (flags & PTF_LEAF)!=0;
@@ -789,10 +794,30 @@ static int getPage(Btree *pBt, Pgno pgno, MemPage **ppPage){
pPage->aData = aData;
pPage->pBt = pBt;
pPage->pgno = pgno;
pPage->hdrOffset = pPage->pgno==1 ? 100 : 0;
*ppPage = pPage;
return SQLITE_OK;
}
/*
** Get a page from the pager and initialize it. This routine
** is just a convenience wrapper around separate calls to
** getPage() and initPage().
*/
static int getAndInitPage(
Btree *pBt, /* The database file */
Pgno pgno, /* Number of the page to get */
MemPage **ppPage, /* Write the page pointer here */
MemPage *pParent /* Parent of the page */
){
int rc;
rc = getPage(pBt, pgno, ppPage);
if( rc==SQLITE_OK ){
rc = initPage(*ppPage, pParent);
}
return rc;
}
/*
** Release a MemPage. This should be called once for each prior
** call to getPage.
@@ -988,7 +1013,7 @@ static int newDatabase(Btree *pBt){
MemPage *pP1;
unsigned char *data;
int rc;
if( sqlite3pager_pagecount(pBt->pPager)>1 ) return SQLITE_OK;
if( sqlite3pager_pagecount(pBt->pPager)>0 ) return SQLITE_OK;
pP1 = pBt->pPage1;
assert( pP1!=0 );
data = pP1->aData;
@@ -1231,11 +1256,7 @@ int sqlite3BtreeCursor(
goto create_cursor_exception;
}
pCur->pgnoRoot = (Pgno)iTable;
rc = getPage(pBt, pCur->pgnoRoot, &pCur->pPage);
if( rc!=SQLITE_OK ){
goto create_cursor_exception;
}
rc = initPage(pCur->pPage, 0);
rc = getAndInitPage(pBt, pCur->pgnoRoot, &pCur->pPage, 0);
if( rc!=SQLITE_OK ){
goto create_cursor_exception;
}
@@ -1338,7 +1359,7 @@ int sqlite3BtreeKeySize(BtCursor *pCur, u64 *pSize){
}else{
unsigned char *cell = pPage->aCell[pCur->idx];
cell += 2; /* Skip the offset to the next cell */
if( pPage->leaf ){
if( !pPage->leaf ){
cell += 4; /* Skip the child pointer */
}
if( !pPage->zeroData ){
@@ -1378,7 +1399,7 @@ static int getPayload(
assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
aPayload = pPage->aCell[pCur->idx];
aPayload += 2; /* Skip the next cell index */
if( pPage->leaf ){
if( !pPage->leaf ){
aPayload += 4; /* Skip the child pointer */
}
if( pPage->zeroData ){
@@ -1497,7 +1518,7 @@ void *sqlite3BtreeKeyFetch(BtCursor *pCur){
assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
aPayload = pPage->aCell[pCur->idx];
aPayload += 2; /* Skip the next cell index */
if( pPage->leaf ){
if( !pPage->leaf ){
aPayload += 4; /* Skip the child pointer */
}
if( !pPage->zeroData ){
@@ -1530,7 +1551,7 @@ int sqlite3BtreeDataSize(BtCursor *pCur, u32 *pSize){
u64 size;
cell = pPage->aCell[pCur->idx];
cell += 2; /* Skip the offset to the next cell */
if( pPage->leaf ){
if( !pPage->leaf ){
cell += 4; /* Skip the child pointer */
}
getVarint(cell, &size);
@@ -1572,9 +1593,7 @@ static int moveToChild(BtCursor *pCur, u32 newPgno){
MemPage *pOldPage;
Btree *pBt = pCur->pBt;
rc = getPage(pBt, newPgno, &pNewPage);
if( rc ) return rc;
rc = initPage(pNewPage, pCur->pPage);
rc = getAndInitPage(pBt, newPgno, &pNewPage, pCur->pPage);
if( rc ) return rc;
pNewPage->idxParent = pCur->idx;
pOldPage = pCur->pPage;
@@ -1600,7 +1619,7 @@ static int moveToChild(BtCursor *pCur, u32 newPgno){
static int isRootPage(MemPage *pPage){
MemPage *pParent = pPage->pParent;
assert( pParent==0 || pParent->isInit );
if( pParent || (pParent->pgno==1 && pParent->nCell==0) ) return 1;
if( pParent==0 || (pParent->pgno==1 && pParent->nCell==0) ) return 1;
return 0;
}
@@ -1666,9 +1685,7 @@ static int moveToRoot(BtCursor *pCur){
int rc;
Btree *pBt = pCur->pBt;
rc = getPage(pBt, pCur->pgnoRoot, &pRoot);
if( rc ) return rc;
rc = initPage(pRoot, 0);
rc = getAndInitPage(pBt, pCur->pgnoRoot, &pRoot, 0);
if( rc ) return rc;
releasePage(pCur->pPage);
pCur->pPage = pRoot;
@@ -1807,7 +1824,7 @@ int sqlite3BtreeMoveto(BtCursor *pCur, const void *pKey, u64 nKey, int *pRes){
void *pCellKey;
u64 nCellKey;
pCur->idx = (lwr+upr)/2;
nCellKey = sqlite3BtreeKeySize(pCur, &nCellKey);
sqlite3BtreeKeySize(pCur, &nCellKey);
if( pPage->intKey ){
if( nCellKey<nKey ){
c = -1;
@@ -2211,6 +2228,7 @@ static int fillInCell(
if( n>nSrc ) n = nSrc;
memcpy(pPayload, pSrc, n);
nPayload -= n;
pPayload += n;
nSrc -= n;
spaceLeft -= n;
if( nSrc==0 ){
@@ -2285,13 +2303,15 @@ static void reparentChildPages(MemPage *pPage){
** the linked list.
*/
static void dropCell(MemPage *pPage, int idx, int sz){
int j;
int j, pc;
assert( idx>=0 && idx<pPage->nCell );
assert( sz==cellSize(pPage, pPage->aCell[idx]) );
assert( sqlite3pager_iswriteable(pPage->aData) );
assert( pPage->aCell[idx]>=pPage->aData );
assert( pPage->aCell[idx]<&pPage->aData[pPage->pBt->pageSize-sz] );
freeSpace(pPage, idx, sz);
pc = Addr(pPage->aCell[idx]) - Addr(pPage->aData);
assert( pc>pPage->hdrOffset && pc+sz<=pPage->pBt->pageSize );
freeSpace(pPage, pc, sz);
for(j=idx; j<pPage->nCell-1; j++){
pPage->aCell[j] = pPage->aCell[j+1];
}
@@ -2344,7 +2364,7 @@ static void relinkCellList(MemPage *pPage){
assert( sqlite3pager_iswriteable(pPage->aData) );
idxFrom = pPage->hdrOffset+3;
for(i=0; i<pPage->nCell; i++){
int idx = Addr(pPage->aCell[i]) - Addr(pPage);
int idx = Addr(pPage->aCell[i]) - Addr(pPage->aData);
assert( idx>pPage->hdrOffset && idx<pPage->pBt->pageSize );
put2byte(&pPage->aData[idxFrom], idx);
idxFrom = idx;
@@ -2620,9 +2640,7 @@ static int balance(MemPage *pPage){
}else{
break;
}
rc = getPage(pBt, pgnoOld[i], &apOld[i]);
if( rc ) goto balance_cleanup;
rc = initPage(apOld[i], pParent);
rc = getAndInitPage(pBt, pgnoOld[i], &apOld[i], pParent);
if( rc ) goto balance_cleanup;
apOld[i]->idxParent = k;
apCopy[i] = 0;
@@ -3053,7 +3071,7 @@ int sqlite3BtreeCreateTable(Btree *pBt, int *piTable, int flags){
rc = allocatePage(pBt, &pRoot, &pgnoRoot, 0);
if( rc ) return rc;
assert( sqlite3pager_iswriteable(pRoot->aData) );
zeroPage(pRoot, flags);
zeroPage(pRoot, flags | PTF_LEAF);
sqlite3pager_unref(pRoot->aData);
*piTable = (int)pgnoRoot;
return SQLITE_OK;
@@ -3074,12 +3092,10 @@ static int clearDatabasePage(
unsigned char *pCell;
int i;
rc = getPage(pBt, pgno, &pPage);
rc = getAndInitPage(pBt, pgno, &pPage, pParent);
if( rc ) return rc;
rc = sqlite3pager_write(pPage->aData);
if( rc ) return rc;
rc = initPage(pPage, pParent);
if( rc ) return rc;
for(i=0; i<pPage->nCell; i++){
pCell = pPage->aCell[i];
if( !pPage->leaf ){
@@ -3183,8 +3199,8 @@ int sqlite3BtreeUpdateMeta(Btree *pBt, int idx, u32 iMeta){
if( !pBt->inTrans ){
return pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
}
rc = sqlite3pager_get(pBt->pPager, 1, (void**)&pP1);
if( rc ) return rc;
assert( pBt->pPage1!=0 );
pP1 = pBt->pPage1->aData;
rc = sqlite3pager_write(pP1);
if( rc ) return rc;
put4byte(&pP1[36 + idx*4], iMeta);
@@ -3218,7 +3234,7 @@ int sqlite3BtreePageDump(Btree *pBt, int pgno, int recursive){
printf("PAGE %d: flags=0x%02x frag=%d\n", pgno,
pPage->aData[pPage->hdrOffset], pPage->aData[pPage->hdrOffset+5]);
i = 0;
hdrOffset = pgno==1 ? 100 : 0;
assert( pPage->hdrOffset == (pgno==1 ? 100 : 0) );
idx = get2byte(&pPage->aData[hdrOffset+3]);
while( idx>0 && idx<=pBt->pageSize ){
u64 nData, nKey;