SQLite

2.8.13

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.130 2004/05/27 09:28:42 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

char const *sqlite3AffinityString(char affinity){
  switch( affinity ){
    case SQLITE_AFF_INTEGER: return "i";

      */
      pExpr->iTable = pParse->nTab++;
      memset(&keyInfo, 0, sizeof(keyInfo));
      keyInfo.nField = 1;
      keyInfo.aColl[0] = pParse->db->pDfltColl;
      sqlite3VdbeOp3(v, OP_OpenTemp, pExpr->iTable, 0, \
           (char*)&keyInfo, P3_KEYINFO);


      if( pExpr->pSelect ){
        /* Case 1:     expr IN (SELECT ...)
        **
        ** Generate code to write the results of the select into the temporary
        ** table allocated and opened above.
        */

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.342 2004/05/28 01:39:01 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

/* Temporary - this is useful in conjunction with prettyPrintMem whilst
** debugging. 
*/
char zGdbBuf[100];
#endif

/*
** Move data out of a btree key or data field and into a Mem structure.
** The data or key is taken from the entry that pCur is currently pointing
** to.  offset and amt determine what portion of the data or key to retrieve.
** key is true to get the key or false to get data.  The result is written
** into the pMem element.
*/
static int getBtreeMem(
  BtCursor *pCur,   /* Cursor pointing at record to retrieve. */
  int offset,       /* Offset from the start of data to return bytes from. */
  int amt,          /* Number of bytes to return. */
  int key,          /* If true, retrieve from the btree key, not data. */
  Mem *pMem         /* OUT: Return data in this Mem structure. */
){
  char *zData;

  if( key ){
    zData = (char *)sqlite3BtreeKeyFetch(pCur, offset+amt);
  }else{
    zData = (char *)sqlite3BtreeDataFetch(pCur, offset+amt);
  }

  if( zData ){
    pMem->z = &zData[offset];
    pMem->n = amt;
    pMem->flags = MEM_Blob|MEM_Ephem;
  }else{
    int rc;
    if( amt>NBFS-2 ){
      zData = (char *)sqliteMallocRaw(amt+2);
      if( !zData ){
        return SQLITE_NOMEM;
      }
      pMem->flags = MEM_Blob|MEM_Dyn|MEM_Term;
    }else{
      zData = &(pMem->zShort[0]);
      pMem->flags = MEM_Blob|MEM_Short|MEM_Term;
    }
    pMem->z = zData;
    pMem->enc = 0;
    pMem->type = SQLITE3_BLOB;

    if( key ){
      rc = sqlite3BtreeKey(pCur, offset, amt, zData);
    }else{
      rc = sqlite3BtreeData(pCur, offset, amt, zData);
    }
    zData[amt] = 0;
    zData[amt+1] = 0;
    if( rc!=SQLITE_OK ){
      if( amt>NBFS ){
        sqliteFree(zData);
      }
      return rc;
    }
  }

  return SQLITE_OK;
}


#ifdef VDBE_PROFILE
/*
** The following routine only works on pentium-class processors.
** It uses the RDTSC opcode to read cycle count value out of the
** processor and returns that value.  This can be used for high-res
** profiling.

*/
case OP_SetNumColumns: {
  assert( (pOp->p1)<p->nCursor );
  p->apCsr[pOp->p1]->nField = pOp->p2;
  break;
}






/* Opcode: Column P1 P2 *
**
** Interpret the data that cursor P1 points to as a structure built using
** the MakeRecord instruction.  (See the MakeRecord opcode for additional
** information about the format of the data.) Push onto the stack the value
** of the P2-th column contained in the data.
**
** If the KeyAsData opcode has previously executed on this cursor, then the
** field might be extracted from the key rather than the data.
**
** If P1 is negative, then the record is stored on the stack rather than in
** a table.  For P1==-1, the top of the stack is used.  For P1==-2, the
** next on the stack is used.  And so forth.  The value pushed is always
** just a pointer into the record which is stored further down on the
** stack.  The column value is not copied. The number of columns in the
** record is stored on the stack just above the record itself.
*/

case OP_Column: {
  int payloadSize;   /* Number of bytes in the record */
  int p1 = pOp->p1;  /* P1 value of the opcode */
  int p2 = pOp->p2;  /* column number to retrieve */
  Cursor *pC = 0;    /* The VDBE cursor */
  char *zRec;        /* Pointer to record-data from stack or pseudo-table. */
  BtCursor *pCrsr;   /* The BTree cursor */

        zData = (char*)sqlite3BtreeDataFetch(pCrsr, sz);
      }
    }
    idx = sqlite3GetVarint32(zData, &szHdr);

    /* Get the complete header text */
    if( !zRec ){
      rc = getBtreeMem(pCrsr, 0, szHdr, pC->keyAsData, &sMem);
      if( rc!=SQLITE_OK ){
        goto abort_due_to_error;
      }
      zData = sMem.z;
    }

    /* Scan the header and use it to fill in the aType[] and aOffset[]

  /* Get the column information.
  */
  if( zRec ){
    zData = &zRec[aOffset[p2]];
  }else{
    len = sqlite3VdbeSerialTypeLen(aType[p2]);
    getBtreeMem(pCrsr, aOffset[p2], len, pC->keyAsData, &sMem);
    zData = sMem.z;
  }
  sqlite3VdbeSerialGet(zData, aType[p2], pTos);
  pTos->enc = db->enc;
  if( rc!=SQLITE_OK ){
    goto abort_due_to_error;
  }
  Release(&sMem);

  /* Release the aType[] memory if we are not dealing with cursor */
  if( !pC ){
    sqliteFree(aType);
  }
  break;
}

/* Opcode MakeRecord P1 * P3
**
** Convert the top P1 entries of the stack into a single entry
** suitable for use as a data record in a database table.  The
** details of the format are irrelavant as long as the OP_Column
** opcode can decode the record later.  Refer to source code
** comments for the details of the record format.
**
** P3 may be a string that is P1 characters long.  The nth character of the
** string indicates the column affinity that should be used for the nth
** field of the index key (i.e. the first character of P3 corresponds to the
** lowest element on the stack).
**
**  Character      Column affinity
**  ------------------------------
**  'n'            NUMERIC
**  'i'            INTEGER
**  't'            TEXT
**  'o'            NONE
**
** If P3 is NULL then all index fields have the affinity NONE.
*/
case OP_MakeRecord: {
  /* Assuming the record contains N fields, the record format looks
  ** like this:
  **
  ** --------------------------------------------------------------------------
  ** | header-siz | type 0 | type 1 | ... | type N-1 | data0 | ... | data N-1 | 
  ** --------------------------------------------------------------------------
  **
  ** Data(0) is taken from the lowest element of the stack and data(N-1) is
  ** the top of the stack.
  **
  ** Each type field is a varint representing the serial type of the 
  ** corresponding data element (see sqlite3VdbeSerialType()). The
  ** num-fields field is also a varint storing N.
  ** 
  ** TODO: Even when the record is short enough for Mem::zShort, this opcode
  **   allocates it dynamically.
  */
  int nField = pOp->p1;
  unsigned char *zNewRecord;
  unsigned char *zCsr;
  char *zAffinity;
  Mem *pRec;
  int nData = 0;     /* Number of bytes of data space */
  int nHdr = 0;      /* Number of bytes of header space */
  int nByte = 0;     /* Space required for this record */

  Mem *pData0 = &pTos[1-nField];
  assert( pData0>=p->aStack );
  zAffinity = pOp->p3;

  /* Loop through the elements that will make up the record to figure
  ** out how much space is required for the new record.
  */
  for(pRec=pData0; pRec<=pTos; pRec++){
    u32 serial_type;
    if( zAffinity ){
      applyAffinity(pRec, zAffinity[pRec-pData0], db->enc);
    }
    serial_type = sqlite3VdbeSerialType(pRec);
    nData += sqlite3VdbeSerialTypeLen(serial_type);
    nHdr += sqlite3VarintLen(serial_type);
  }
  nHdr += sqlite3VarintLen(nHdr);
  nByte = nHdr+nData;

  if( nByte>MAX_BYTES_PER_ROW ){
    rc = SQLITE_TOOBIG;
    goto abort_due_to_error;
  }

  /* Allocate space for the new record. */
  zNewRecord = sqliteMallocRaw(nByte);
  if( !zNewRecord ){
    goto no_mem;
  }

  /* Write the record */
  zCsr = zNewRecord;
  zCsr += sqlite3PutVarint(zCsr, nHdr);
  for(pRec=pData0; pRec<=pTos; pRec++){
    u32 serial_type = sqlite3VdbeSerialType(pRec);
    zCsr += sqlite3PutVarint(zCsr, serial_type);      /* serial type */
  }
  for(pRec=pData0; pRec<=pTos; pRec++){
    zCsr += sqlite3VdbeSerialPut(zCsr, pRec);  /* serial data */
  }

  /* If zCsr has not been advanced exactly nByte bytes, then one
  ** of the sqlite3PutVarint() or sqlite3VdbeSerialPut() calls above
  ** failed. This indicates a corrupted memory cell or code bug.
  */
  if( zCsr!=(zNewRecord+nByte) ){
    rc = SQLITE_INTERNAL;
    goto abort_due_to_error;
  }

  /* Pop nField entries from the stack and push the new entry on */
  popStack(&pTos, nField);
  pTos++;
  pTos->n = nByte;
  pTos->z = zNewRecord;
  pTos->flags = MEM_Blob | MEM_Dyn;

  break;
}

/* Opcode: MakeKey P1 P2 P3
**
** Convert the top P1 entries of the stack into a single entry suitable
** for use as the key in an index. If P2 is zero, then the original 

**  'n'            NUMERIC
**  'i'            INTEGER
**  't'            TEXT
**  'o'            NONE
**
** If P3 is NULL then datatype coercion occurs.
*/






















case OP_MakeKey:
case OP_MakeIdxKey: {
  Mem *pRec;
  Mem *pData0;
  int nField;
  u64 rowid;
  int nByte = 0;
  int addRowid;
  int containsNull = 0;
  char *zKey;      /* The new key */
  int offset = 0;
  char *zAffinity = pOp->p3;
 
  nField = pOp->p1;
  assert( zAffinity==0 || strlen(zAffinity)>=nField );


  pData0 = &pTos[1-nField];
  assert( pData0>=p->aStack );




























  addRowid = ((pOp->opcode==OP_MakeIdxKey)?1:0);


  /* Loop through the P1 elements that will make up the new index
  ** key. Call applyAffinity() to perform any conversion required
  ** the column affinity string P3 to modify stack elements in place.
  ** Set containsNull to 1 if a NULL value is encountered.
  **
  ** Once the value has been coerced, figure out how much space is required
  ** to store the coerced values serial-type and blob, and add this
  ** quantity to nByte.
  **
  ** TODO: Figure out if the in-place coercion causes a problem for
  ** OP_MakeKey when P2 is 0 (used by DISTINCT).
  */
  for(pRec=pData0; pRec<=pTos; pRec++){
    u32 serial_type;
    if( zAffinity ){
      applyAffinity(pRec, zAffinity[pRec-pData0], db->enc);
    }
    if( pRec->flags&MEM_Null ){
      containsNull = 1;
    }
    serial_type = sqlite3VdbeSerialType(pRec);
    nByte += sqlite3VarintLen(serial_type);
    nByte += sqlite3VdbeSerialTypeLen(serial_type);

  }

  /* If we have to append a varint rowid to this record, set 'rowid'
  ** to the value of the rowid and increase nByte by the amount of space
  ** required to store it and the 0x00 seperator byte.
  */
  if( addRowid ){
    pRec = &pTos[0-nField];
    assert( pRec>=p->aStack );
    Integerify(pRec, db->enc);
    rowid = pRec->i;

    nByte += sqlite3VarintLen(rowid);
    nByte++;
  }
  




  if( nByte>MAX_BYTES_PER_ROW ){
    rc = SQLITE_TOOBIG;
    goto abort_due_to_error;
  }

  /* Allocate space for the new key */
  zKey = (char *)sqliteMallocRaw(nByte);
  if( !zKey ){
    goto no_mem;
  }
  
  /* Build the key in the buffer pointed to by zKey. */


  for(pRec=pData0; pRec<=pTos; pRec++){
    u32 serial_type = sqlite3VdbeSerialType(pRec);



    offset += sqlite3PutVarint(&zKey[offset], serial_type);


    offset += sqlite3VdbeSerialPut(&zKey[offset], pRec);
  }
  if( addRowid ){
    zKey[offset++] = '\0';
    offset += sqlite3PutVarint(&zKey[offset], rowid);
  }
  assert( offset==nByte );








  /* Pop the consumed values off the stack and push on the new key. */

  if( addRowid||(pOp->p2==0) ){
    popStack(&pTos, nField+addRowid);
  }
  pTos++;
  pTos->flags = MEM_Blob|MEM_Dyn;
  pTos->z = zKey;
  pTos->n = nByte;

  /* If P2 is non-zero, and if the key contains a NULL value, and if this
  ** was an OP_MakeIdxKey instruction, not OP_MakeKey, jump to P2.
  */
  if( pOp->p2 && containsNull && addRowid ){
    pc = pOp->p2 - 1;
  }

** The top of the stack is an integer record number.  Call this
** record number R.  The next on the stack is an index key created
** using MakeIdxKey.  Call it K.  This instruction pops R from the
** stack but it leaves K unchanged.
**
** P1 is an index.  So it has no data and its key consists of a
** record generated by OP_MakeIdxKey.  This key contains one or more
** fields followed by a varint ROWID.
**
** This instruction asks if there is an entry in P1 where the
** fields matches K but the rowid is different from R.
** If there is no such entry, then there is an immediate
** jump to P2.  If any entry does exist where the index string
** matches K but the record number is not R, then the record
** number for that entry is pushed onto the stack and control
** falls through to the next instruction.

  pCrsr = pCx->pCursor;
  if( pCrsr!=0 ){
    int res, rc;
    i64 v;         /* The record number on the P1 entry that matches K */
    char *zKey;    /* The value of K */
    int nKey;      /* Number of bytes in K */
    int len;       /* Number of bytes in K without the rowid at the end */


    /* Make sure K is a string and make zKey point to K
    */
    Stringify(pNos, db->enc);
    zKey = pNos->z;
    nKey = pNos->n;

    assert( nKey >= 2 );
    len = nKey-2;
    while( zKey[len] && --len );

    /* Search for an entry in P1 where all but the last four bytes match K.
    ** If there is no such entry, jump immediately to P2.
    */
    assert( pCx->deferredMoveto==0 );
    pCx->cacheValid = 0;
    rc = sqlite3BtreeMoveto(pCrsr, zKey, len, &res);

    if( rc!=SQLITE_OK ) goto abort_due_to_error;
    if( res>0 ){
      pc = pOp->p2 - 1;
      break;
    }

    /* At this point, pCrsr is pointing to an entry in P1 where all but
    ** the final varint (the rowid) matches K.  Check to see if the
    ** final varint is different from R.  If it equals R then jump
    ** immediately to P2.
    */
    rc = sqlite3VdbeIdxRowid(pCrsr, &v);
    if( rc!=SQLITE_OK ){
      goto abort_due_to_error;
    }
    if( v==R ){

    v = keyToInt(v);
  }
  pTos->i = v;
  pTos->flags = MEM_Int;
  break;
}

/* Opcode: IdxColumn P1 * *
**
** P1 is a cursor opened on an index. Push the first field from the
** current index key onto the stack.
*/
case OP_IdxColumn: {
  char *zData;
  i64 n;
  u32 serial_type;
  int len;
  int freeZData = 0;
  BtCursor *pCsr;

  assert( 0==p->apCsr[pOp->p1]->intKey );
  pCsr = p->apCsr[pOp->p1]->pCursor;
  rc = sqlite3BtreeKeySize(pCsr, &n);
  if( rc!=SQLITE_OK ){
    goto abort_due_to_error;
  }
  if( n>10 ) n = 10;

  zData = (char *)sqlite3BtreeKeyFetch(pCsr, n);
  assert( zData );

  len = sqlite3GetVarint32(zData, &serial_type);
  n = sqlite3VdbeSerialTypeLen(serial_type);

  zData = (char *)sqlite3BtreeKeyFetch(pCsr, len+n);
  if( !zData ){
    zData = (char *)sqliteMalloc(n);
    if( !zData ){
      goto no_mem;
    }
    rc = sqlite3BtreeKey(pCsr, len, n, zData);
    if( rc!=SQLITE_OK ){
      sqliteFree(zData);
      goto abort_due_to_error;
    }
    freeZData = 1;
    len = 0;
  }

  pTos++;
  sqlite3VdbeSerialGet(&zData[len], serial_type, pTos);
  pTos->enc = db->enc;
  if( freeZData ){
    sqliteFree(zData);
  }
  break;
}

/* Opcode: FullKey P1 * *
**
** Extract the complete key from the record that cursor P1 is currently
** pointing to and push the key onto the stack as a string.
**
** Compare this opcode to Recno.  The Recno opcode extracts the first
** 4 bytes of the key and pushes those bytes onto the stack as an

  assert( pTos->flags & MEM_Blob );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int nKey = pTos->n;
    const char *zKey = pTos->z;
    if( pOp->p2 ){
      int res;
      int len;
      u64 n;
   
      /* 'len' is the length of the key minus the rowid at the end */
      len = nKey-2;
      while( zKey[len] && --len );

      rc = sqlite3BtreeMoveto(pCrsr, zKey, len, &res);
      if( rc!=SQLITE_OK ) goto abort_due_to_error;
      while( res!=0 ){
        int c;
        sqlite3BtreeKeySize(pCrsr, &n);
        if( n==nKey && 
            sqlite3VdbeIdxKeyCompare(pC, len, zKey, &c)==SQLITE_OK
            && c==0
        ){
          rc = SQLITE_CONSTRAINT;
          if( pOp->p3 && pOp->p3[0] ){
            sqlite3SetString(&p->zErrMsg, pOp->p3, (char*)0);
          }
          goto abort_due_to_error;
        }
        if( res<0 ){

    pTos->flags = MEM_Null;
  }
  break;
}

/* Opcode: IdxGT P1 P2 *
**
** Compare the top of the stack against the key on the index entry that
** cursor P1 is currently pointing to.  Ignore the ROWID of the




** index entry.  If the index entry is greater than the top of the stack
** then jump to P2.  Otherwise fall through to the next instruction.
** In either case, the stack is popped once.
*/
/* Opcode: IdxGE P1 P2 P3
**
** Compare the top of the stack against the key on the index entry that
** cursor P1 is currently pointing to.  Ignore the ROWID of the
** index entry.  If the index in the cursor is greater than or equal to 

** the top of the stack
** then jump to P2.  Otherwise fall through to the next instruction.
** In either case, the stack is popped once.
**
** If P3 is the "+" string (or any other non-NULL string) then the
** index taken from the top of the stack is temporarily increased by
** an epsilon prior to the comparison.  This make the opcode work
** like IdxGT except that if the key from the stack is a prefix of
** the key in the cursor, the result is false whereas it would be
** true with IdxGT.
*/
/* Opcode: IdxLT P1 P2 P3
**
** Compare the top of the stack against the key on the index entry that
** cursor P1 is currently pointing to.  Ignore the ROWID of the


** index entry.  If the index entry is less than the top of the stack
** then jump to P2.  Otherwise fall through to the next instruction.
** In either case, the stack is popped once.
**
** If P3 is the "+" string (or any other non-NULL string) then the
** index taken from the top of the stack is temporarily increased by
** an epsilon prior to the comparison.  This makes the opcode work
** like IdxLE.
*/
case OP_IdxLT:
case OP_IdxGT:
case OP_IdxGE: {
  int i= pOp->p1;
  BtCursor *pCrsr;
  Cursor *pC;

  assert( i>=0 && i<p->nCursor );
  assert( pTos>=p->aStack );
  if( (pCrsr = (pC = p->apCsr[i])->pCursor)!=0 ){
    int res, rc;
 

    Stringify(pTos, db->enc);
    assert( pC->deferredMoveto==0 );
    *pC->pIncrKey = pOp->p3!=0;
    assert( pOp->p3==0 || pOp->opcode!=OP_IdxGT );
    rc = sqlite3VdbeIdxKeyCompare(pC, pTos->n, pTos->z, &res);
    *pC->pIncrKey = 0;
    if( rc!=SQLITE_OK ){

**
** The index entry is always popped from the stack.
*/
case OP_IdxIsNull: {
  int i = pOp->p1;
  int k, n;
  const char *z;


  assert( pTos>=p->aStack );
  assert( pTos->flags & MEM_Blob );
  z = pTos->z;
  n = pTos->n;

  for(k=0; k<n && i>0; i--){
    u32 serial_type;
    k += sqlite3GetVarint32(&z[k], &serial_type);
    if( serial_type==6 ){   /* Serial type 6 is a NULL */
      pc = pOp->p2-1;
      break;
    }
    k += sqlite3VdbeSerialTypeLen(serial_type);
  }
  Release(pTos);
  pTos--;
  break;
}

/* Opcode: Destroy P1 P2 *