** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.253 2005/03/21 04:04:02 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
................................................................................
** If this routine fails for any reason, it might leave the database
** in a corrupted state.  So if this routine fails, the database should
** be rolled back.
*/
static int balance_nonroot(MemPage *pPage){
  MemPage *pParent;            /* The parent of pPage */
  Btree *pBt;                  /* The whole database */
  int nCell = 0;               /* Number of cells in aCell[] */

  int nOld;                    /* Number of pages in apOld[] */
  int nNew;                    /* Number of pages in apNew[] */
  int nDiv;                    /* Number of cells in apDiv[] */
  int i, j, k;                 /* Loop counters */
  int idx;                     /* Index of pPage in pParent->aCell[] */
  int nxDiv;                   /* Next divider slot in pParent->aCell[] */
  int rc;                      /* The return code */
  int leafCorrection;          /* 4 if pPage is a leaf.  0 if not */
  int leafData;                /* True if pPage is a leaf of a LEAFDATA tree */
  int usableSpace;             /* Bytes in pPage beyond the header */
  int pageFlags;               /* Value of pPage->aData[0] */
  int subtotal;                /* Subtotal of bytes in cells on one page */
  int iSpace = 0;              /* First unused byte of aSpace[] */
  int mxCellPerPage;           /* Maximum number of cells in one page */
  MemPage *apOld[NB];          /* pPage and up to two siblings */
  Pgno pgnoOld[NB];            /* Page numbers for each page in apOld[] */
  MemPage *apCopy[NB];         /* Private copies of apOld[] pages */
  MemPage *apNew[NB+2];        /* pPage and up to NB siblings after balancing */
  Pgno pgnoNew[NB+2];          /* Page numbers for each page in apNew[] */
  int idxDiv[NB];              /* Indices of divider cells in pParent */
  u8 *apDiv[NB];               /* Divider cells in pParent */
................................................................................
    ** TODO: Check the siblings to the left of pPage. It may be that
    ** they are not full and no new page is required.
    */
    return balance_quick(pPage, pParent);
  }
#endif

  /*
  ** Allocate space for memory structures
  */
  mxCellPerPage = MX_CELL(pBt);
  apCell = sqliteMallocRaw( 
       (mxCellPerPage+2)*NB*(sizeof(u8*)+sizeof(int))
     + sizeof(MemPage)*NB
     + pBt->psAligned*(5+NB)
     + (ISAUTOVACUUM ? (mxCellPerPage+2)*NN*2 : 0)
  );
  if( apCell==0 ){
    return SQLITE_NOMEM;
  }
  szCell = (int*)&apCell[(mxCellPerPage+2)*NB];
  aCopy[0] = (u8*)&szCell[(mxCellPerPage+2)*NB];
  for(i=1; i<NB; i++){
    aCopy[i] = &aCopy[i-1][pBt->psAligned+sizeof(MemPage)];
  }
  aSpace = &aCopy[NB-1][pBt->psAligned+sizeof(MemPage)];
#ifndef SQLITE_OMIT_AUTOVACUUM
  if( pBt->autoVacuum ){
    aFrom = &aSpace[5*pBt->psAligned];
  }
#endif
  
  /*
  ** Find the cell in the parent page whose left child points back
  ** to pPage.  The "idx" variable is the index of that cell.  If pPage
  ** is the rightmost child of pParent then set idx to pParent->nCell 
  */
  if( pParent->idxShift ){
    Pgno pgno;
................................................................................
    }
    rc = getAndInitPage(pBt, pgnoOld[i], &apOld[i], pParent);
    if( rc ) goto balance_cleanup;
    apOld[i]->idxParent = k;
    apCopy[i] = 0;
    assert( i==nOld );
    nOld++;

  }



























  /*
  ** Make copies of the content of pPage and its siblings into aOld[].
  ** The rest of this function will use data from the copies rather
  ** that the original pages since the original pages will be in the
  ** process of being overwritten.
  */
  for(i=0; i<nOld; i++){
................................................................................
  nCell = 0;
  leafCorrection = pPage->leaf*4;
  leafData = pPage->leafData && pPage->leaf;
  for(i=0; i<nOld; i++){
    MemPage *pOld = apCopy[i];
    int limit = pOld->nCell+pOld->nOverflow;
    for(j=0; j<limit; j++){

      apCell[nCell] = findOverflowCell(pOld, j);
      szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
#ifndef SQLITE_OMIT_AUTOVACUUM
      if( pBt->autoVacuum ){
        int a;
        aFrom[nCell] = i;
        for(a=0; a<pOld->nOverflow; a++){
................................................................................
        ** are duplicates of keys on the child pages.  We need to remove
        ** the divider cells from pParent, but the dividers cells are not
        ** added to apCell[] because they are duplicates of child cells.
        */
        dropCell(pParent, nxDiv, sz);
      }else{
        u8 *pTemp;

        szCell[nCell] = sz;
        pTemp = &aSpace[iSpace];
        iSpace += sz;
        assert( iSpace<=pBt->psAligned*5 );
        memcpy(pTemp, apDiv[i], sz);
        apCell[nCell] = pTemp+leafCorrection;
#ifndef SQLITE_OMIT_AUTOVACUUM
................................................................................
  **   cntNew[i]: Index in apCell[] and szCell[] for the first cell to
  **              the right of the i-th sibling page.
  ** usableSpace: Number of bytes of space available on each sibling.
  ** 
  */
  usableSpace = pBt->usableSize - 12 + leafCorrection;
  for(subtotal=k=i=0; i<nCell; i++){

    subtotal += szCell[i] + 2;
    if( subtotal > usableSpace ){
      szNew[k] = subtotal - szCell[i];
      cntNew[k] = i;
      if( leafData ){ i--; }
      subtotal = 0;
      k++;
................................................................................
    int szRight = szNew[i];  /* Size of sibling on the right */
    int szLeft = szNew[i-1]; /* Size of sibling on the left */
    int r;              /* Index of right-most cell in left sibling */
    int d;              /* Index of first cell to the left of right sibling */

    r = cntNew[i-1] - 1;
    d = r + 1 - leafData;


    while( szRight==0 || szRight+szCell[d]+2<=szLeft-(szCell[r]+2) ){
      szRight += szCell[d] + 2;
      szLeft -= szCell[r] + 2;
      cntNew[i-1]--;
      r = cntNew[i-1] - 1;
      d = r + 1 - leafData;
    }
................................................................................
  /*
  ** Evenly distribute the data in apCell[] across the new pages.
  ** Insert divider cells into pParent as necessary.
  */
  j = 0;
  for(i=0; i<nNew; i++){
    /* Assemble the new sibling page. */

    MemPage *pNew = apNew[i];
    assert( pNew->pgno==pgnoNew[i] );
    assemblePage(pNew, cntNew[i]-j, &apCell[j], &szCell[j]);
    assert( pNew->nCell>0 );
    assert( pNew->nOverflow==0 );

#ifndef SQLITE_OMIT_AUTOVACUUM
................................................................................
    /* If this is an auto-vacuum database, update the pointer map entries
    ** that point to the siblings that were rearranged. These can be: left
    ** children of cells, the right-child of the page, or overflow pages
    ** pointed to by cells.
    */
    if( pBt->autoVacuum ){
      for(k=j; k<cntNew[i]; k++){

        if( aFrom[k]==0xFF || apCopy[aFrom[k]]->pgno!=pNew->pgno ){
          rc = ptrmapPutOvfl(pNew, k-j);
          if( rc!=SQLITE_OK ){
            goto balance_cleanup;
          }
        }
      }
................................................................................
    /* If the sibling page assembled above was not the right-most sibling,
    ** insert a divider cell into the parent page.
    */
    if( i<nNew-1 && j<nCell ){
      u8 *pCell;
      u8 *pTemp;
      int sz;


      pCell = apCell[j];
      sz = szCell[j] + leafCorrection;
      if( !pNew->leaf ){
        memcpy(&pNew->aData[8], pCell, 4);
        pTemp = 0;
      }else if( leafData ){
	/* If the tree is a leaf-data tree, and the siblings are leaves, 

** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.254 2005/03/28 08:44:07 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
................................................................................
** If this routine fails for any reason, it might leave the database
** in a corrupted state.  So if this routine fails, the database should
** be rolled back.
*/
static int balance_nonroot(MemPage *pPage){
  MemPage *pParent;            /* The parent of pPage */
  Btree *pBt;                  /* The whole database */
  int nCell = 0;               /* Number of cells in apCell[] */
  int nMaxCells = 0;           /* Allocated size of apCell, szCell, aFrom. */
  int nOld;                    /* Number of pages in apOld[] */
  int nNew;                    /* Number of pages in apNew[] */
  int nDiv;                    /* Number of cells in apDiv[] */
  int i, j, k;                 /* Loop counters */
  int idx;                     /* Index of pPage in pParent->aCell[] */
  int nxDiv;                   /* Next divider slot in pParent->aCell[] */
  int rc;                      /* The return code */
  int leafCorrection;          /* 4 if pPage is a leaf.  0 if not */
  int leafData;                /* True if pPage is a leaf of a LEAFDATA tree */
  int usableSpace;             /* Bytes in pPage beyond the header */
  int pageFlags;               /* Value of pPage->aData[0] */
  int subtotal;                /* Subtotal of bytes in cells on one page */
  int iSpace = 0;              /* First unused byte of aSpace[] */

  MemPage *apOld[NB];          /* pPage and up to two siblings */
  Pgno pgnoOld[NB];            /* Page numbers for each page in apOld[] */
  MemPage *apCopy[NB];         /* Private copies of apOld[] pages */
  MemPage *apNew[NB+2];        /* pPage and up to NB siblings after balancing */
  Pgno pgnoNew[NB+2];          /* Page numbers for each page in apNew[] */
  int idxDiv[NB];              /* Indices of divider cells in pParent */
  u8 *apDiv[NB];               /* Divider cells in pParent */
................................................................................
    ** TODO: Check the siblings to the left of pPage. It may be that
    ** they are not full and no new page is required.
    */
    return balance_quick(pPage, pParent);
  }
#endif


























  /*
  ** Find the cell in the parent page whose left child points back
  ** to pPage.  The "idx" variable is the index of that cell.  If pPage
  ** is the rightmost child of pParent then set idx to pParent->nCell 
  */
  if( pParent->idxShift ){
    Pgno pgno;
................................................................................
    }
    rc = getAndInitPage(pBt, pgnoOld[i], &apOld[i], pParent);
    if( rc ) goto balance_cleanup;
    apOld[i]->idxParent = k;
    apCopy[i] = 0;
    assert( i==nOld );
    nOld++;
    nMaxCells += 1+apOld[i]->nCell+apOld[i]->nOverflow;
  }

  /*
  ** Allocate space for memory structures
  */
  apCell = sqliteMallocRaw( 
       nMaxCells*sizeof(u8*)                           /* apCell */
     + nMaxCells*sizeof(int)                           /* szCell */
     + sizeof(MemPage)*NB                              /* aCopy */
     + pBt->psAligned*(5+NB)                           /* aSpace */
     + (ISAUTOVACUUM ? nMaxCells : 0)     /* aFrom */
  );
  if( apCell==0 ){
    rc = SQLITE_NOMEM;
    goto balance_cleanup;
  }
  szCell = (int*)&apCell[nMaxCells];
  aCopy[0] = (u8*)&szCell[nMaxCells];
  for(i=1; i<NB; i++){
    aCopy[i] = &aCopy[i-1][pBt->psAligned+sizeof(MemPage)];
  }
  aSpace = &aCopy[NB-1][pBt->psAligned+sizeof(MemPage)];
#ifndef SQLITE_OMIT_AUTOVACUUM
  if( pBt->autoVacuum ){
    aFrom = &aSpace[5*pBt->psAligned];
  }
#endif
  
  /*
  ** Make copies of the content of pPage and its siblings into aOld[].
  ** The rest of this function will use data from the copies rather
  ** that the original pages since the original pages will be in the
  ** process of being overwritten.
  */
  for(i=0; i<nOld; i++){
................................................................................
  nCell = 0;
  leafCorrection = pPage->leaf*4;
  leafData = pPage->leafData && pPage->leaf;
  for(i=0; i<nOld; i++){
    MemPage *pOld = apCopy[i];
    int limit = pOld->nCell+pOld->nOverflow;
    for(j=0; j<limit; j++){
      assert( nCell<nMaxCells );
      apCell[nCell] = findOverflowCell(pOld, j);
      szCell[nCell] = cellSizePtr(pOld, apCell[nCell]);
#ifndef SQLITE_OMIT_AUTOVACUUM
      if( pBt->autoVacuum ){
        int a;
        aFrom[nCell] = i;
        for(a=0; a<pOld->nOverflow; a++){
................................................................................
        ** are duplicates of keys on the child pages.  We need to remove
        ** the divider cells from pParent, but the dividers cells are not
        ** added to apCell[] because they are duplicates of child cells.
        */
        dropCell(pParent, nxDiv, sz);
      }else{
        u8 *pTemp;
        assert( nCell<nMaxCells );
        szCell[nCell] = sz;
        pTemp = &aSpace[iSpace];
        iSpace += sz;
        assert( iSpace<=pBt->psAligned*5 );
        memcpy(pTemp, apDiv[i], sz);
        apCell[nCell] = pTemp+leafCorrection;
#ifndef SQLITE_OMIT_AUTOVACUUM
................................................................................
  **   cntNew[i]: Index in apCell[] and szCell[] for the first cell to
  **              the right of the i-th sibling page.
  ** usableSpace: Number of bytes of space available on each sibling.
  ** 
  */
  usableSpace = pBt->usableSize - 12 + leafCorrection;
  for(subtotal=k=i=0; i<nCell; i++){
    assert( i<nMaxCells );
    subtotal += szCell[i] + 2;
    if( subtotal > usableSpace ){
      szNew[k] = subtotal - szCell[i];
      cntNew[k] = i;
      if( leafData ){ i--; }
      subtotal = 0;
      k++;
................................................................................
    int szRight = szNew[i];  /* Size of sibling on the right */
    int szLeft = szNew[i-1]; /* Size of sibling on the left */
    int r;              /* Index of right-most cell in left sibling */
    int d;              /* Index of first cell to the left of right sibling */

    r = cntNew[i-1] - 1;
    d = r + 1 - leafData;
    assert( d<nMaxCells );
    assert( r<nMaxCells );
    while( szRight==0 || szRight+szCell[d]+2<=szLeft-(szCell[r]+2) ){
      szRight += szCell[d] + 2;
      szLeft -= szCell[r] + 2;
      cntNew[i-1]--;
      r = cntNew[i-1] - 1;
      d = r + 1 - leafData;
    }
................................................................................
  /*
  ** Evenly distribute the data in apCell[] across the new pages.
  ** Insert divider cells into pParent as necessary.
  */
  j = 0;
  for(i=0; i<nNew; i++){
    /* Assemble the new sibling page. */
    assert( j<nMaxCells );
    MemPage *pNew = apNew[i];
    assert( pNew->pgno==pgnoNew[i] );
    assemblePage(pNew, cntNew[i]-j, &apCell[j], &szCell[j]);
    assert( pNew->nCell>0 );
    assert( pNew->nOverflow==0 );

#ifndef SQLITE_OMIT_AUTOVACUUM
................................................................................
    /* If this is an auto-vacuum database, update the pointer map entries
    ** that point to the siblings that were rearranged. These can be: left
    ** children of cells, the right-child of the page, or overflow pages
    ** pointed to by cells.
    */
    if( pBt->autoVacuum ){
      for(k=j; k<cntNew[i]; k++){
        assert( k<nMaxCells );
        if( aFrom[k]==0xFF || apCopy[aFrom[k]]->pgno!=pNew->pgno ){
          rc = ptrmapPutOvfl(pNew, k-j);
          if( rc!=SQLITE_OK ){
            goto balance_cleanup;
          }
        }
      }
................................................................................
    /* If the sibling page assembled above was not the right-most sibling,
    ** insert a divider cell into the parent page.
    */
    if( i<nNew-1 && j<nCell ){
      u8 *pCell;
      u8 *pTemp;
      int sz;

      assert( j<nMaxCells );
      pCell = apCell[j];
      sz = szCell[j] + leafCorrection;
      if( !pNew->leaf ){
        memcpy(&pNew->aData[8], pCell, 4);
        pTemp = 0;
      }else if( leafData ){
	/* If the tree is a leaf-data tree, and the siblings are leaves, 

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.199 2005/03/28 03:39:56 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
#define DATA_TO_PGHDR(D)  (&((PgHdr*)(D))[-1])
#define PGHDR_TO_EXTRA(G,P) ((void*)&((char*)(&(G)[1]))[(P)->psAligned])
#define PGHDR_TO_HIST(P,PGR)  \
            ((PgHistory*)&((char*)(&(P)[1]))[(PGR)->psAligned+(PGR)->nExtra])

/*
** How big to make the hash table used for locating in-memory pages
** by page number.

*/
#define N_PG_HASH 2048







/*
** Hash a page number
*/
#define pager_hash(PN)  ((PN)&(N_PG_HASH-1))

/*

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.200 2005/03/28 08:44:07 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
#define DATA_TO_PGHDR(D)  (&((PgHdr*)(D))[-1])
#define PGHDR_TO_EXTRA(G,P) ((void*)&((char*)(&(G)[1]))[(P)->psAligned])
#define PGHDR_TO_HIST(P,PGR)  \
            ((PgHistory*)&((char*)(&(P)[1]))[(PGR)->psAligned+(PGR)->nExtra])

/*
** How big to make the hash table used for locating in-memory pages
** by page number. This macro looks a little silly, but is evaluated
** at compile-time, not run-time (at least for gcc this is true).
*/
#define N_PG_HASH (\
  (MAX_PAGES>1024)?2048: \
  (MAX_PAGES>512)?1024: \
  (MAX_PAGES>256)?512: \
  (MAX_PAGES>128)?256: \
  (MAX_PAGES>64)?128:64 \
)

/*
** Hash a page number
*/
#define pager_hash(PN)  ((PN)&(N_PG_HASH-1))

/*

*/
void sqlite3VdbeTrace(Vdbe *p, FILE *trace){
  p->trace = trace;
}

/*
** Resize the Vdbe.aOp array so that it contains at least N


** elements.
*/
static void resizeOpArray(Vdbe *p, int N){




  if( p->nOpAlloc<N ){
    int oldSize = p->nOpAlloc;
    p->nOpAlloc = N+100;
    p->aOp = sqliteRealloc(p->aOp, p->nOpAlloc*sizeof(Op));
    if( p->aOp ){
      memset(&p->aOp[oldSize], 0, (p->nOpAlloc-oldSize)*sizeof(Op));
    }
  }
................................................................................

/*
** Loop through the program looking for P2 values that are negative.
** Each such value is a label.  Resolve the label by setting the P2
** value to its correct non-zero value.
**
** This routine is called once after all opcodes have been inserted.




*/
static void resolveP2Values(Vdbe *p){
  int i;

  Op *pOp;
  int *aLabel = p->aLabel;
  if( aLabel==0 ) return;
  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){










    if( pOp->p2>=0 ) continue;
    assert( -1-pOp->p2<p->nLabel );
    pOp->p2 = aLabel[-1-pOp->p2];
  }
  sqliteFree(p->aLabel);
  p->aLabel = 0;

}

/*
** Return the address of the next instruction to be inserted.
*/
int sqlite3VdbeCurrentAddr(Vdbe *p){
  assert( p->magic==VDBE_MAGIC_INIT );
................................................................................

  assert( p!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );

  /* There should be at least one opcode.
  */
  assert( p->nOp>0 );








  /* No instruction ever pushes more than a single element onto the
  ** stack.  And the stack never grows on successive executions of the
  ** same loop.  So the total number of instructions is an upper bound
  ** on the maximum stack depth required.
  **
  ** Allocation all the stack space we will ever need.
  */
  if( p->aStack==0 ){

    resolveP2Values(p);

    assert( nVar>=0 );
    n = isExplain ? 10 : p->nOp;
    p->aStack = sqliteMalloc(
        n*sizeof(p->aStack[0])         /* aStack */
      + n*sizeof(Mem*)                 /* apArg */
      + nVar*sizeof(Mem)               /* aVar */
      + nVar*sizeof(char*)             /* azVar */
      + nMem*sizeof(Mem)               /* aMem */
      + nCursor*sizeof(Cursor*)        /* apCsr */
      + nAgg*sizeof(Agg)               /* Aggregate contexts */
    );
    if( !sqlite3_malloc_failed ){
      p->aMem = &p->aStack[n];
      p->nMem = nMem;
      p->aVar = &p->aMem[nMem];
      p->nVar = nVar;
      p->okVar = 0;
      p->apArg = (Mem**)&p->aVar[nVar];
      p->azVar = (char**)&p->apArg[n];
      p->apCsr = (Cursor**)&p->azVar[nVar];
      if( nAgg>0 ){
        p->nAgg = nAgg;
        p->apAgg = (Agg*)&p->apCsr[nCursor];
      }
      p->nCursor = nCursor;
      for(n=0; n<nVar; n++){

*/
void sqlite3VdbeTrace(Vdbe *p, FILE *trace){
  p->trace = trace;
}

/*
** Resize the Vdbe.aOp array so that it contains at least N
** elements. If the Vdbe is in VDBE_MAGIC_RUN state, then
** the Vdbe.aOp array will be sized to contain exactly N 
** elements.
*/
static void resizeOpArray(Vdbe *p, int N){
  if( p->magic==VDBE_MAGIC_RUN ){
    assert( N==p->nOp );
    p->nOpAlloc = N;
    p->aOp = sqliteRealloc(p->aOp, N*sizeof(Op));
  }else if( p->nOpAlloc<N ){
    int oldSize = p->nOpAlloc;
    p->nOpAlloc = N+100;
    p->aOp = sqliteRealloc(p->aOp, p->nOpAlloc*sizeof(Op));
    if( p->aOp ){
      memset(&p->aOp[oldSize], 0, (p->nOpAlloc-oldSize)*sizeof(Op));
    }
  }
................................................................................

/*
** Loop through the program looking for P2 values that are negative.
** Each such value is a label.  Resolve the label by setting the P2
** value to its correct non-zero value.
**
** This routine is called once after all opcodes have been inserted.
**
** Variable *pMaxFuncArgs is set to the maximum value of any P1 argument 
** to an OP_Function or P2 to an OP_AggFunc opcode. This is used by 
** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.
*/
static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs){
  int i;
  int nMax = 0;
  Op *pOp;
  int *aLabel = p->aLabel;
  if( aLabel==0 ) return;
  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
    u8 opcode = pOp->opcode;

    /* Todo: Maybe OP_AggFunc should change to use P1 in the same
     * way as OP_Function. */
    if( opcode==OP_Function ){
      if( pOp->p1>nMax ) nMax = pOp->p1;
    }else if( opcode==OP_AggFunc ){
      if( pOp->p2>nMax ) nMax = pOp->p2;
    }

    if( pOp->p2>=0 ) continue;
    assert( -1-pOp->p2<p->nLabel );
    pOp->p2 = aLabel[-1-pOp->p2];
  }
  sqliteFree(p->aLabel);
  p->aLabel = 0;
  *pMaxFuncArgs = nMax;
}

/*
** Return the address of the next instruction to be inserted.
*/
int sqlite3VdbeCurrentAddr(Vdbe *p){
  assert( p->magic==VDBE_MAGIC_INIT );
................................................................................

  assert( p!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );

  /* There should be at least one opcode.
  */
  assert( p->nOp>0 );

  /* Set the magic to VDBE_MAGIC_RUN sooner rather than later. This
   * is because the call to resizeOpArray() below may shrink the
   * p->aOp[] array to save memory if called when in VDBE_MAGIC_RUN 
   * state.
   */
  p->magic = VDBE_MAGIC_RUN;

  /* No instruction ever pushes more than a single element onto the
  ** stack.  And the stack never grows on successive executions of the
  ** same loop.  So the total number of instructions is an upper bound
  ** on the maximum stack depth required.
  **
  ** Allocation all the stack space we will ever need.
  */
  if( p->aStack==0 ){
    int nArg;       /* Maximum number of args passed to a user function. */
    resolveP2Values(p, &nArg);
    resizeOpArray(p, p->nOp);
    assert( nVar>=0 );
    n = isExplain ? 10 : p->nOp;
    p->aStack = sqliteMalloc(
        n*sizeof(p->aStack[0])         /* aStack */
      + nArg*sizeof(Mem*)              /* apArg */
      + nVar*sizeof(Mem)               /* aVar */
      + nVar*sizeof(char*)             /* azVar */
      + nMem*sizeof(Mem)               /* aMem */
      + nCursor*sizeof(Cursor*)        /* apCsr */
      + nAgg*sizeof(Agg)               /* Aggregate contexts */
    );
    if( !sqlite3_malloc_failed ){
      p->aMem = &p->aStack[n];
      p->nMem = nMem;
      p->aVar = &p->aMem[nMem];
      p->nVar = nVar;
      p->okVar = 0;
      p->apArg = (Mem**)&p->aVar[nVar];
      p->azVar = (char**)&p->apArg[nArg];
      p->apCsr = (Cursor**)&p->azVar[nVar];
      if( nAgg>0 ){
        p->nAgg = nAgg;
        p->apAgg = (Agg*)&p->apCsr[nCursor];
      }
      p->nCursor = nCursor;
      for(n=0; n<nVar; n++){

application binary (or interpreter) and the second argument the name of the
text file that contains the collected stderr output.

If all goes well a summary of unfreed allocations is printed out. If the
GNU C library is in use and SQLITE_DEBUG is 3 or greater a stack trace is
printed out for each unmatched allocation.





Example:

$ ./testfixture ../sqlite/test/select1.test 2> memtrace.out
$ tclsh $argv0 ./testfixture memtrace.out
"








# If stack traces are enabled, the 'addr2line' program is called to
# translate a binary stack address into a human-readable form.
set addr2line addr2line

if { [llength $argv]!=2 } {
  puts "Usage: $argv0 <binary file> <mem trace file>"
  puts ""
  puts [string trim $doco]
  exit -1






















}











proc process_input {input_file array_name} {
  upvar $array_name mem 
  set input [open $input_file]

  set MALLOC {([[:digit:]]+) malloc ([[:digit:]]+) bytes at 0x([[:xdigit:]]+)}
  # set STACK {^[[:digit:]]+: STACK: (.*)$}
................................................................................

    } elseif { [regexp $MALLOC $line dummy mallocid bytes addr]  } {
      # If this is a 'malloc' line, set an entry in the mem array. Each entry
      # is a list of length three, the number of bytes allocated , the malloc
      # number and the stack dump when it was allocated.
      set mem($addr) [list $bytes "malloc $mallocid" $stack]
      set stack ""












    } elseif { [regexp $FREE $line dummy bytes addr] } {
      # If this is a 'free' line, remove the entry from the mem array. If the 
      # entry does not exist, or is the wrong number of bytes, announce a
      # problem. This is more likely a bug in the regular expressions for
      # this script than an SQLite defect.
      if { [lindex $mem($addr) 0] != $bytes } {
        error "byte count mismatch"
      }
      unset mem($addr) 




    } elseif { [regexp $REALLOC $line dummy mallocid ob b oa a] } {
      # If it is a realloc line, remove the old mem entry and add a new one.


      unset mem($oa);


      set mem($a) [list $b "realloc $mallocid" $stack]

      set stack ""









    } else {
      # puts "REJECT: $line"
    }


  }

  close $input
}

process_input [lindex $argv 1] mem
set exe [lindex $argv 0]



foreach key [array names mem] {
  set bytes [lindex $mem($key) 0]
  set mallocid [lindex $mem($key) 1]
  set stack [lindex $mem($key) 2]
  puts "Leaked $bytes bytes at 0x$key: $mallocid"
  foreach frame [lrange $stack 1 10] {
    foreach {f l} [split [exec $addr2line -f --exe=$exe $frame] \n] {}
    puts [format "%-30s %s" $f $l]
  }
  if {[llength $stack]>0 } {puts ""}
}

application binary (or interpreter) and the second argument the name of the
text file that contains the collected stderr output.

If all goes well a summary of unfreed allocations is printed out. If the
GNU C library is in use and SQLITE_DEBUG is 3 or greater a stack trace is
printed out for each unmatched allocation.

If the \"-r <n>\" option is passed, then the program stops and prints out
the state of the heap immediately after the <n>th call to malloc() or
realloc().

Example:

$ ./testfixture ../sqlite/test/select1.test 2> memtrace.out
$ tclsh $argv0 ?-r <malloc-number>? ./testfixture memtrace.out
"
if { [llength $argv]!=2 && [llength $argv]!=4 } {
  set prg [file tail $argv0]
  puts "Usage: $prg ?-r <malloc-number>? <binary file> <mem trace file>"
  puts ""
  puts [string trim $doco]
  exit -1
}

# If stack traces are enabled, the 'addr2line' program is called to
# translate a binary stack address into a human-readable form.
set addr2line addr2line






# When the SQLITE_MEMDEBUG is set as described above, SQLite prints
# out a line for each malloc(), realloc() or free() call that the
# library makes. If SQLITE_MEMDEBUG is 3, then a stack trace is printed
# out before each malloc() and realloc() line.
#
# This program parses each line the SQLite library outputs and updates
# the following global Tcl variables to reflect the "current" state of
# the heap used by SQLite.
#
set nBytes 0               ;# Total number of bytes currently allocated.
set nMalloc 0              ;# Total number of malloc()/realloc() calls.
set nPeak 0                ;# Peak of nBytes.
set iPeak 0                ;# nMalloc when nPeak was set.
#
# More detailed state information is stored in the $memmap array. 
# Each key in the memmap array is the address of a chunk of memory
# currently allocated from the heap. The value is a list of the 
# following form
# 
#     {<number-of-bytes> <malloc id> <stack trace>}
#
array unset memmap

# The executable program being analyzed.
if {[llength $argv]==2} {
  set exe [lindex $argv 0]
  set memfile [lindex $argv 1]
  set report_at -1
} else {
  set exe [lindex $argv 2]
  set memfile [lindex $argv 3]
  set report_at [lindex $argv 1]
}

proc process_input {input_file array_name} {
  upvar $array_name mem 
  set input [open $input_file]

  set MALLOC {([[:digit:]]+) malloc ([[:digit:]]+) bytes at 0x([[:xdigit:]]+)}
  # set STACK {^[[:digit:]]+: STACK: (.*)$}
................................................................................

    } elseif { [regexp $MALLOC $line dummy mallocid bytes addr]  } {
      # If this is a 'malloc' line, set an entry in the mem array. Each entry
      # is a list of length three, the number of bytes allocated , the malloc
      # number and the stack dump when it was allocated.
      set mem($addr) [list $bytes "malloc $mallocid" $stack]
      set stack ""

      # Increase the current heap usage
      incr ::nBytes $bytes

      # Increase the number of malloc() calls
      incr ::nMalloc

      if {$::nBytes > $::nPeak} {
        set ::nPeak $::nBytes
        set ::iPeak $::nMalloc
      }

    } elseif { [regexp $FREE $line dummy bytes addr] } {
      # If this is a 'free' line, remove the entry from the mem array. If the 
      # entry does not exist, or is the wrong number of bytes, announce a
      # problem. This is more likely a bug in the regular expressions for
      # this script than an SQLite defect.
      if { [lindex $mem($addr) 0] != $bytes } {
        error "byte count mismatch"
      }
      unset mem($addr) 

      # Decrease the current heap usage
      incr ::nBytes [expr -1 * $bytes]

    } elseif { [regexp $REALLOC $line dummy mallocid ob b oa a] } {

      # "free" the old allocation in the internal model:
      incr ::nBytes [expr -1 * $ob]
      unset mem($oa);

      # "malloc" the new allocation
      set mem($a) [list $b "realloc $mallocid" $stack]
      incr ::nBytes $b
      set stack ""

      # Increase the number of malloc() calls
      incr ::nMalloc

      if {$::nBytes > $::nPeak} {
        set ::nPeak $::nBytes
        set ::iPeak $::nMalloc
      }

    } else {
      # puts "REJECT: $line"
    }

    if {$::nMalloc==$::report_at} report
  }

  close $input
}

proc printstack {stack} {
  set fcount 10
  if {[llength $stack]<10} {
    set fcount [llength $stack]
  }





  foreach frame [lrange $stack 1 $fcount] {
    foreach {f l} [split [exec $::addr2line -f --exe=$::exe $frame] \n] {}
    puts [format "%-30s %s" $f $l]
  }
  if {[llength $stack]>0 } {puts ""}
}

proc report {} {

  foreach key [array names ::memmap] {
    set stack [lindex $::memmap($key) 2]
    set bytes [lindex $::memmap($key) 0]
    lappend summarymap($stack) $bytes
  }

  foreach stack [array names summarymap] {
    set allocs $summarymap($stack)
    set sum 0
    foreach a $allocs {
      incr sum $a
    }
    lappend sorted [list $sum $stack]
  }

  set sorted [lsort -integer -index 0 $sorted]
  foreach s $sorted {
    set sum [lindex $s 0]
    set stack [lindex $s 1]
    set allocs $summarymap($stack)
    puts "$sum bytes in [llength $allocs] chunks ($allocs)"
    printstack $stack
  }

  # Print out summary statistics
  puts "Total allocations            : $::nMalloc"
  puts "Total outstanding allocations: [array size ::memmap]" 
  puts "Current heap usage           : $::nBytes bytes"
  puts "Peak heap usage              : $::nPeak bytes (malloc #$::iPeak)"

  exit
}

process_input $memfile memmap
report