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Overview
Comment:Add the exprNodeCopy() routine that will safely memcpy() an Expr node that might be a size-reduced node.
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SHA3-256:a874c649960ba2e2b2fd380d08c02a45884a1060d3922be8847729008ca6766e
User & Date: drh 2019-01-05 21:56:12
Context
2019-05-07
02:57
Add the exprNodeCopy() routine that will safely memcpy() an Expr node that might be a size-reduced node. Leaf check-in: ab2ba8e7 user: drh tags: expr-node-copy-patch
2019-01-06
02:06
The page size becomes fixed as soon as page1 from a non-empty database file is read. check-in: 6064584d user: drh tags: trunk
01:46
Give symbolic names to the special prepared statements used to implement incremental blob I/O. Leaf check-in: 2a1cc632 user: drh tags: named-blob-I/O
2019-01-05
21:56
Add the exprNodeCopy() routine that will safely memcpy() an Expr node that might be a size-reduced node. check-in: a874c649 user: drh tags: trunk
21:09
If the OP_ParseSchema opcode with a non-NULL P4 operand does not parse any rows out of the sqlite_master table, that indicates that the sqlite_master table is corrupt, so raise an SQLITE_CORRUPT error. check-in: 598d7358 user: drh tags: trunk
Changes
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Changes to src/expr.c.

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** EXPR_REDUCEDSIZE or EXPR_TOKENONLYSIZE.
*/
static int exprStructSize(Expr *p){
  if( ExprHasProperty(p, EP_TokenOnly) ) return EXPR_TOKENONLYSIZE;
  if( ExprHasProperty(p, EP_Reduced) ) return EXPR_REDUCEDSIZE;
  return EXPR_FULLSIZE;
}











/*
** The dupedExpr*Size() routines each return the number of bytes required
** to store a copy of an expression or expression tree.  They differ in
** how much of the tree is measured.
**
**     dupedExprStructSize()     Size of only the Expr structure 
................................................................................
      assert( !ExprHasProperty(pExpr, EP_xIsSelect) && pExpr->x.pList );
      assert(pExpr->x.pList->nExpr > 0);
      pEList = pExpr->x.pList;
      aListelem = pEList->a;
      nExpr = pEList->nExpr;
      endLabel = sqlite3VdbeMakeLabel(pParse);
      if( (pX = pExpr->pLeft)!=0 ){
        tempX = *pX;
        testcase( pX->op==TK_COLUMN );
        exprToRegister(&tempX, exprCodeVector(pParse, &tempX, &regFree1));
        testcase( regFree1==0 );
        memset(&opCompare, 0, sizeof(opCompare));
        opCompare.op = TK_EQ;
        opCompare.pLeft = &tempX;
        pTest = &opCompare;
................................................................................
){
 Expr exprAnd;     /* The AND operator in  x>=y AND x<=z  */
  Expr compLeft;    /* The  x>=y  term */
  Expr compRight;   /* The  x<=z  term */
  Expr exprX;       /* The  x  subexpression */
  int regFree1 = 0; /* Temporary use register */


  memset(&compLeft, 0, sizeof(Expr));
  memset(&compRight, 0, sizeof(Expr));
  memset(&exprAnd, 0, sizeof(Expr));

  assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
  exprX = *pExpr->pLeft;
  exprAnd.op = TK_AND;
  exprAnd.pLeft = &compLeft;
  exprAnd.pRight = &compRight;
  compLeft.op = TK_GE;
  compLeft.pLeft = &exprX;
  compLeft.pRight = pExpr->x.pList->a[0].pExpr;
  compRight.op = TK_LE;







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** EXPR_REDUCEDSIZE or EXPR_TOKENONLYSIZE.
*/
static int exprStructSize(Expr *p){
  if( ExprHasProperty(p, EP_TokenOnly) ) return EXPR_TOKENONLYSIZE;
  if( ExprHasProperty(p, EP_Reduced) ) return EXPR_REDUCEDSIZE;
  return EXPR_FULLSIZE;
}

/*
** Copy the complete content of an Expr node, taking care not to read
** past the end of the structure for a reduced-size version of the source
** Expr.
*/
static void exprNodeCopy(Expr *pDest, Expr *pSrc){
  memset(pDest, 0, sizeof(Expr));
  memcpy(pDest, pSrc, exprStructSize(pSrc));
}

/*
** The dupedExpr*Size() routines each return the number of bytes required
** to store a copy of an expression or expression tree.  They differ in
** how much of the tree is measured.
**
**     dupedExprStructSize()     Size of only the Expr structure 
................................................................................
      assert( !ExprHasProperty(pExpr, EP_xIsSelect) && pExpr->x.pList );
      assert(pExpr->x.pList->nExpr > 0);
      pEList = pExpr->x.pList;
      aListelem = pEList->a;
      nExpr = pEList->nExpr;
      endLabel = sqlite3VdbeMakeLabel(pParse);
      if( (pX = pExpr->pLeft)!=0 ){
        exprNodeCopy(&tempX, pX);
        testcase( pX->op==TK_COLUMN );
        exprToRegister(&tempX, exprCodeVector(pParse, &tempX, &regFree1));
        testcase( regFree1==0 );
        memset(&opCompare, 0, sizeof(opCompare));
        opCompare.op = TK_EQ;
        opCompare.pLeft = &tempX;
        pTest = &opCompare;
................................................................................
){
 Expr exprAnd;     /* The AND operator in  x>=y AND x<=z  */
  Expr compLeft;    /* The  x>=y  term */
  Expr compRight;   /* The  x<=z  term */
  Expr exprX;       /* The  x  subexpression */
  int regFree1 = 0; /* Temporary use register */


  memset(&compLeft, 0, sizeof(Expr));
  memset(&compRight, 0, sizeof(Expr));
  memset(&exprAnd, 0, sizeof(Expr));

  assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
  exprNodeCopy(&exprX, pExpr->pLeft);
  exprAnd.op = TK_AND;
  exprAnd.pLeft = &compLeft;
  exprAnd.pRight = &compRight;
  compLeft.op = TK_GE;
  compLeft.pLeft = &exprX;
  compLeft.pRight = pExpr->x.pList->a[0].pExpr;
  compRight.op = TK_LE;