SQLite

**
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** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.288 2004/05/14 11:00:53 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

  pTos->n = nBytes;
  pTos->z = zNewRecord;
  pTos->flags = MEM_Str | 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.  The top P1 records are
** converted to strings and merged.  The null-terminators 
** are retained and used as separators.
** The lowest entry in the stack is the first field and the top of the
** stack becomes the last.
**
** If P2 is not zero, then the original entries remain on the stack
** and the new key is pushed on top.  If P2 is zero, the original
** data is popped off the stack first then the new key is pushed
** back in its place.
**
** P3 is a string that is P1 characters long.  Each character is either
** an 'n' or a 't' to indicates if the argument should be intepreted as
** numeric or text type.  The first character of P3 corresponds to the
** lowest element on the stack.  If P3 is NULL then all arguments are
** assumed to be of the numeric type.
**
** The type makes a difference in that text-type fields may not be 
** introduced by 'b' (as described in the next paragraph).  The
** first character of a text-type field must be either 'a' (if it is NULL)
** or 'c'.  Numeric fields will be introduced by 'b' if their content
** looks like a well-formed number.  Otherwise the 'a' or 'c' will be
** used.
**
** The key is a concatenation of fields.  Each field is terminated by
** a single 0x00 character.  A NULL field is introduced by an 'a' and
** is followed immediately by its 0x00 terminator.  A numeric field is
** introduced by a single character 'b' and is followed by a sequence
** of characters that represent the number such that a comparison of
** the character string using memcpy() sorts the numbers in numerical
** order.  The character strings for numbers are generated using the
** sqlite3RealToSortable() function.  A text field is introduced by a
** 'c' character and is followed by the exact text of the field.  The
** use of an 'a', 'b', or 'c' character at the beginning of each field
** guarantees that NULLs sort before numbers and that numbers sort
** before text.  0x00 characters do not occur except as separators
** between fields.
**
** See also: MakeIdxKey, SortMakeKey
*/
/* Opcode: MakeIdxKey P1 P2 P3
**
** Convert the top P1 entries of the stack into a single entry suitable
** for use as the key in an index.  In addition, take one additional integer
** off of the stack, treat that integer as an eight-byte record number, and
** append the integer to the key.  Thus a total of P1+1 entries are
** popped from the stack for this instruction and a single entry is pushed
** back.  The first P1 entries that are popped are strings and the last
** entry (the lowest on the stack) is an integer record number.
**
** The converstion of the first P1 string entries occurs just like in
** MakeKey.  Each entry is separated from the others by a null.
** The entire concatenation is null-terminated.  The lowest entry
** in the stack is the first field and the top of the stack becomes the
** last.
**
** If P2 is not zero and one or more of the P1 entries that go into the
** generated key is NULL, then jump to P2 after the new key has been
** pushed on the stack.  In other words, jump to P2 if the key is
** guaranteed to be unique.  This jump can be used to skip a subsequent
** uniqueness test.
**
** P3 is a string that is P1 characters long.  Each character is either
** an 'n' or a 't' to indicates if the argument should be numeric or
** text.  The first character corresponds to the lowest element on the
** stack.  If P3 is null then all arguments are assumed to be numeric.
**
** See also:  MakeKey, SortMakeKey
*/
case OP_MakeIdxKey2:
case OP_MakeKey2: {
  char *zNewKey;
  int nByte;
  int nField;
  int addRowid;
  int i, j;
  int containsNull = 0;
  Mem *pRec;
  char zTemp[NBFS];

  addRowid = pOp->opcode==OP_MakeIdxKey;
  nField = pOp->p1;
  pRec = &pTos[1-nField];
  assert( pRec>=p->aStack );
  nByte = 0;
  for(j=0, i=0; i<nField; i++, j++, pRec++){
    int flags = pRec->flags;
    int len;
    char *z;
    if( flags & MEM_Null ){
      nByte += 2;
      containsNull = 1;
    }else if( pOp->p3 && pOp->p3[j]=='t' ){
      Stringify(pRec);
      pRec->flags &= ~(MEM_Int|MEM_Real);
      nByte += pRec->n+1;
    }else if( (flags & (MEM_Real|MEM_Int))!=0 || sqlite3IsNumber(pRec->z, 0) ){
      if( (flags & (MEM_Real|MEM_Int))==MEM_Int ){
        pRec->r = pRec->i;
      }else if( (flags & (MEM_Real|MEM_Int))==0 ){
        pRec->r = sqlite3AtoF(pRec->z, 0);
      }
      Release(pRec);
      z = pRec->zShort;
      sqlite3RealToSortable(pRec->r, z);
      len = strlen(z);
      pRec->z = 0;
      pRec->flags = MEM_Real;
      pRec->n = len+1;
      nByte += pRec->n+1;
    }else{
      nByte += pRec->n+1;
    }
  }
  if( nByte+sizeof(u32)>MAX_BYTES_PER_ROW ){
    rc = SQLITE_TOOBIG;
    goto abort_due_to_error;
  }
  if( addRowid ) nByte += sizeof(i64);
  if( nByte<=NBFS ){
    zNewKey = zTemp;
  }else{
    zNewKey = sqliteMallocRaw( nByte );
    if( zNewKey==0 ) goto no_mem;
  }
  j = 0;
  pRec = &pTos[1-nField];
  for(i=0; i<nField; i++, pRec++){
    if( pRec->flags & MEM_Null ){
      zNewKey[j++] = 'a';
      zNewKey[j++] = 0;
    }else if( pRec->flags==MEM_Real ){
      zNewKey[j++] = 'b';
      memcpy(&zNewKey[j], pRec->zShort, pRec->n);
      j += pRec->n;
    }else{
      assert( pRec->flags & MEM_Str );
      zNewKey[j++] = 'c';
      memcpy(&zNewKey[j], pRec->z, pRec->n);
      j += pRec->n;
    }
  }
  if( addRowid ){
    i64 iKey;
    pRec = &pTos[-nField];
    assert( pRec>=p->aStack );
    Integerify(pRec);
    iKey = intToKey(pRec->i);
    memcpy(&zNewKey[j], &iKey, sizeof(i64));
    popStack(&pTos, nField+1);
    if( pOp->p2 && containsNull ) pc = pOp->p2 - 1;
  }else{
    if( pOp->p2==0 ) popStack(&pTos, nField);
  }
  pTos++;
  pTos->n = nByte;
  if( nByte<=NBFS ){
    assert( zNewKey==zTemp );
    pTos->z = pTos->zShort;
    memcpy(pTos->zShort, zTemp, nByte);
    pTos->flags = MEM_Str | MEM_Short;
  }else{
    pTos->z = zNewKey;
    pTos->flags = MEM_Str | 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 not zero, then the original 
** entries are popped off the stack. If P2 is zero, the original entries
** remain on the stack.
**

  */
  if( pOp->p2 && containsNull && addRowid ){
    pc = pOp->p2 - 1;
  }
  break;
}

/* Opcode: IncrKey * * *
**
** The top of the stack should contain an index key generated by
** The MakeKey opcode.  This routine increases the least significant
** byte of that key by one.  This is used so that the MoveTo opcode
** will move to the first entry greater than the key rather than to
** the key itself.
**
*/
case OP_IncrKey: {
  assert( pTos>=p->aStack );
  /* The IncrKey opcode is only applied to keys generated by
  ** MakeKey or MakeIdxKey and the results of those operands
  ** are always dynamic strings or zShort[] strings.  So we
  ** are always free to modify the string in place.
  */
  assert( pTos->flags & (MEM_Dyn|MEM_Short) );
  /*
  ** FIX ME: This technique is now broken due to manifest types in index
  ** keys.
  */
  assert(0);
  pTos->z[pTos->n-1]++;
  break;
}

/* Opcode: Checkpoint P1 * *
**
** Begin a checkpoint.  A checkpoint is the beginning of a operation that
** is part of a larger transaction but which might need to be rolled back
** itself without effecting the containing transaction.  A checkpoint will
** be automatically committed or rollback when the VDBE halts.
**

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.
**
** $Id: where.c,v 1.92 2004/05/14 11:00:53 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by an AND operator.

      sqlite3VdbeAddOp(v, OP_Goto, 0, brk);
      sqlite3VdbeAddOp(v, OP_MakeKey, nColumn, 0);
      sqlite3AddIdxKeyType(v, pIdx);
      sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 0);
      if( nColumn==pIdx->nColumn || pLevel->bRev ){
        testOp = OP_IdxGT;
      }else{
/*
        sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
        sqlite3VdbeAddOp(v, OP_IncrKey, 0, 0);
        sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
*/
        testOp = OP_IdxGE;
      }
      if( pLevel->bRev ){
        /* Scan in reverse order */
        /* sqlite3VdbeAddOp(v, OP_IncrKey, 0, 0); */
        sqlite3VdbeAddOp(v, OP_MoveLt, pLevel->iCur, brk);
        sqlite3VdbeChangeP3(v, -1, "+", P3_STATIC);
        start = sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
        sqlite3VdbeAddOp(v, OP_IdxLT, pLevel->iCur, brk);
        pLevel->op = OP_Prev;
      }else{
        /* Scan in the forward order */

        int nCol = nEqColumn + (score & 1);
        pLevel->iMem = pParse->nMem++;
        sqlite3VdbeAddOp(v, OP_NotNull, -nCol, sqlite3VdbeCurrentAddr(v)+3);
        sqlite3VdbeAddOp(v, OP_Pop, nCol, 0);
        sqlite3VdbeAddOp(v, OP_Goto, 0, brk);
        sqlite3VdbeAddOp(v, OP_MakeKey, nCol, 0);
        sqlite3AddIdxKeyType(v, pIdx);
/*
        if( leFlag ){
          sqlite3VdbeAddOp(v, OP_IncrKey, 0, 0);
        }
*/
        if( pLevel->bRev ){
          sqlite3VdbeAddOp(v, OP_MoveLt, pLevel->iCur, brk);
          if( !geFlag ){
            sqlite3VdbeChangeP3(v, -1, "+", P3_STATIC);
          }
        }else{
          sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);

      if( nEqColumn>0 || (score&2)!=0 ){
        int nCol = nEqColumn + ((score&2)!=0);
        sqlite3VdbeAddOp(v, OP_NotNull, -nCol, sqlite3VdbeCurrentAddr(v)+3);
        sqlite3VdbeAddOp(v, OP_Pop, nCol, 0);
        sqlite3VdbeAddOp(v, OP_Goto, 0, brk);
        sqlite3VdbeAddOp(v, OP_MakeKey, nCol, 0);
        sqlite3AddIdxKeyType(v, pIdx);
/*
        if( !geFlag ){
          sqlite3VdbeAddOp(v, OP_IncrKey, 0, 0);
        }
*/
        if( pLevel->bRev ){
          pLevel->iMem = pParse->nMem++;
          sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
          testOp = OP_IdxLT;
        }else{
          sqlite3VdbeAddOp(v, OP_MoveTo, pLevel->iCur, brk);
          if( !geFlag ){