Adding upstream version 3.45.1.upstream/3.45.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2025 insertions, 0 deletions

diff --git a/src/vdbemem.c b/src/vdbemem.c
new file mode 100644
index 0000000..d527164
--- /dev/null
+++ b/src/vdbemem.c
@@ -0,0 +1,2025 @@
+/*
+** 2004 May 26
+**
+** The author disclaims copyright to this source code.  In place of
+** 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.
+**
+*************************************************************************
+**
+** This file contains code use to manipulate "Mem" structure.  A "Mem"
+** stores a single value in the VDBE.  Mem is an opaque structure visible
+** only within the VDBE.  Interface routines refer to a Mem using the
+** name sqlite_value
+*/
+#include "sqliteInt.h"
+#include "vdbeInt.h"
+
+/* True if X is a power of two.  0 is considered a power of two here.
+** In other words, return true if X has at most one bit set.
+*/
+#define ISPOWEROF2(X)  (((X)&((X)-1))==0)
+
+#ifdef SQLITE_DEBUG
+/*
+** Check invariants on a Mem object.
+**
+** This routine is intended for use inside of assert() statements, like
+** this:    assert( sqlite3VdbeCheckMemInvariants(pMem) );
+*/
+int sqlite3VdbeCheckMemInvariants(Mem *p){
+  /* If MEM_Dyn is set then Mem.xDel!=0.  
+  ** Mem.xDel might not be initialized if MEM_Dyn is clear.
+  */
+  assert( (p->flags & MEM_Dyn)==0 || p->xDel!=0 );
+
+  /* MEM_Dyn may only be set if Mem.szMalloc==0.  In this way we
+  ** ensure that if Mem.szMalloc>0 then it is safe to do
+  ** Mem.z = Mem.zMalloc without having to check Mem.flags&MEM_Dyn.
+  ** That saves a few cycles in inner loops. */
+  assert( (p->flags & MEM_Dyn)==0 || p->szMalloc==0 );
+
+  /* Cannot have more than one of MEM_Int, MEM_Real, or MEM_IntReal */
+  assert( ISPOWEROF2(p->flags & (MEM_Int|MEM_Real|MEM_IntReal)) );
+
+  if( p->flags & MEM_Null ){
+    /* Cannot be both MEM_Null and some other type */
+    assert( (p->flags & (MEM_Int|MEM_Real|MEM_Str|MEM_Blob|MEM_Agg))==0 );
+
+    /* If MEM_Null is set, then either the value is a pure NULL (the usual
+    ** case) or it is a pointer set using sqlite3_bind_pointer() or
+    ** sqlite3_result_pointer().  If a pointer, then MEM_Term must also be
+    ** set.
+    */
+    if( (p->flags & (MEM_Term|MEM_Subtype))==(MEM_Term|MEM_Subtype) ){
+      /* This is a pointer type.  There may be a flag to indicate what to
+      ** do with the pointer. */
+      assert( ((p->flags&MEM_Dyn)!=0 ? 1 : 0) +
+              ((p->flags&MEM_Ephem)!=0 ? 1 : 0) +
+              ((p->flags&MEM_Static)!=0 ? 1 : 0) <= 1 );
+
+      /* No other bits set */
+      assert( (p->flags & ~(MEM_Null|MEM_Term|MEM_Subtype|MEM_FromBind
+                           |MEM_Dyn|MEM_Ephem|MEM_Static))==0 );
+    }else{
+      /* A pure NULL might have other flags, such as MEM_Static, MEM_Dyn,
+      ** MEM_Ephem, MEM_Cleared, or MEM_Subtype */
+    }
+  }else{
+    /* The MEM_Cleared bit is only allowed on NULLs */
+    assert( (p->flags & MEM_Cleared)==0 );
+  }
+
+  /* The szMalloc field holds the correct memory allocation size */
+  assert( p->szMalloc==0
+       || (p->flags==MEM_Undefined 
+           && p->szMalloc<=sqlite3DbMallocSize(p->db,p->zMalloc))
+       || p->szMalloc==sqlite3DbMallocSize(p->db,p->zMalloc));
+
+  /* If p holds a string or blob, the Mem.z must point to exactly
+  ** one of the following:
+  **
+  **   (1) Memory in Mem.zMalloc and managed by the Mem object
+  **   (2) Memory to be freed using Mem.xDel
+  **   (3) An ephemeral string or blob
+  **   (4) A static string or blob
+  */
+  if( (p->flags & (MEM_Str|MEM_Blob)) && p->n>0 ){
+    assert( 
+      ((p->szMalloc>0 && p->z==p->zMalloc)? 1 : 0) +
+      ((p->flags&MEM_Dyn)!=0 ? 1 : 0) +
+      ((p->flags&MEM_Ephem)!=0 ? 1 : 0) +
+      ((p->flags&MEM_Static)!=0 ? 1 : 0) == 1
+    );
+  }
+  return 1;
+}
+#endif
+
+/*
+** Render a Mem object which is one of MEM_Int, MEM_Real, or MEM_IntReal
+** into a buffer.
+*/
+static void vdbeMemRenderNum(int sz, char *zBuf, Mem *p){
+  StrAccum acc;
+  assert( p->flags & (MEM_Int|MEM_Real|MEM_IntReal) );
+  assert( sz>22 );
+  if( p->flags & MEM_Int ){
+#if GCC_VERSION>=7000000
+    /* Work-around for GCC bug
+    ** https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96270 */
+    i64 x;
+    assert( (p->flags&MEM_Int)*2==sizeof(x) );
+    memcpy(&x, (char*)&p->u, (p->flags&MEM_Int)*2);
+    p->n = sqlite3Int64ToText(x, zBuf);
+#else
+    p->n = sqlite3Int64ToText(p->u.i, zBuf);
+#endif
+  }else{
+    sqlite3StrAccumInit(&acc, 0, zBuf, sz, 0);
+    sqlite3_str_appendf(&acc, "%!.15g", 
+         (p->flags & MEM_IntReal)!=0 ? (double)p->u.i : p->u.r);
+    assert( acc.zText==zBuf && acc.mxAlloc<=0 );
+    zBuf[acc.nChar] = 0; /* Fast version of sqlite3StrAccumFinish(&acc) */
+    p->n = acc.nChar;
+  }
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** Validity checks on pMem.  pMem holds a string.
+**
+** (1) Check that string value of pMem agrees with its integer or real value.
+** (2) Check that the string is correctly zero terminated
+**
+** A single int or real value always converts to the same strings.  But
+** many different strings can be converted into the same int or real.
+** If a table contains a numeric value and an index is based on the
+** corresponding string value, then it is important that the string be
+** derived from the numeric value, not the other way around, to ensure
+** that the index and table are consistent.  See ticket
+** https://www.sqlite.org/src/info/343634942dd54ab (2018-01-31) for
+** an example.
+**
+** This routine looks at pMem to verify that if it has both a numeric
+** representation and a string representation then the string rep has
+** been derived from the numeric and not the other way around.  It returns
+** true if everything is ok and false if there is a problem.
+**
+** This routine is for use inside of assert() statements only.
+*/
+int sqlite3VdbeMemValidStrRep(Mem *p){
+  Mem tmp;
+  char zBuf[100];
+  char *z;
+  int i, j, incr;
+  if( (p->flags & MEM_Str)==0 ) return 1;
+  if( p->db && p->db->mallocFailed ) return 1;
+  if( p->flags & MEM_Term ){
+    /* Insure that the string is properly zero-terminated.  Pay particular
+    ** attention to the case where p->n is odd */
+    if( p->szMalloc>0 && p->z==p->zMalloc ){
+      assert( p->enc==SQLITE_UTF8 || p->szMalloc >= ((p->n+1)&~1)+2 );
+      assert( p->enc!=SQLITE_UTF8 || p->szMalloc >= p->n+1 );
+    }
+    assert( p->z[p->n]==0 );
+    assert( p->enc==SQLITE_UTF8 || p->z[(p->n+1)&~1]==0 );
+    assert( p->enc==SQLITE_UTF8 || p->z[((p->n+1)&~1)+1]==0 );
+  }
+  if( (p->flags & (MEM_Int|MEM_Real|MEM_IntReal))==0 ) return 1;
+  memcpy(&tmp, p, sizeof(tmp));
+  vdbeMemRenderNum(sizeof(zBuf), zBuf, &tmp);
+  z = p->z;
+  i = j = 0;
+  incr = 1;
+  if( p->enc!=SQLITE_UTF8 ){
+    incr = 2;
+    if( p->enc==SQLITE_UTF16BE ) z++;
+  }
+  while( zBuf[j] ){
+    if( zBuf[j++]!=z[i] ) return 0;
+    i += incr;
+  }
+  return 1;
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** If pMem is an object with a valid string representation, this routine
+** ensures the internal encoding for the string representation is
+** 'desiredEnc', one of SQLITE_UTF8, SQLITE_UTF16LE or SQLITE_UTF16BE.
+**
+** If pMem is not a string object, or the encoding of the string
+** representation is already stored using the requested encoding, then this
+** routine is a no-op.
+**
+** SQLITE_OK is returned if the conversion is successful (or not required).
+** SQLITE_NOMEM may be returned if a malloc() fails during conversion
+** between formats.
+*/
+int sqlite3VdbeChangeEncoding(Mem *pMem, int desiredEnc){
+#ifndef SQLITE_OMIT_UTF16
+  int rc;
+#endif
+  assert( pMem!=0 );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( desiredEnc==SQLITE_UTF8 || desiredEnc==SQLITE_UTF16LE
+           || desiredEnc==SQLITE_UTF16BE );
+  if( !(pMem->flags&MEM_Str) ){
+    pMem->enc = desiredEnc;
+    return SQLITE_OK;
+  }
+  if( pMem->enc==desiredEnc ){
+    return SQLITE_OK;
+  }
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+#ifdef SQLITE_OMIT_UTF16
+  return SQLITE_ERROR;
+#else
+
+  /* MemTranslate() may return SQLITE_OK or SQLITE_NOMEM. If NOMEM is returned,
+  ** then the encoding of the value may not have changed.
+  */
+  rc = sqlite3VdbeMemTranslate(pMem, (u8)desiredEnc);
+  assert(rc==SQLITE_OK    || rc==SQLITE_NOMEM);
+  assert(rc==SQLITE_OK    || pMem->enc!=desiredEnc);
+  assert(rc==SQLITE_NOMEM || pMem->enc==desiredEnc);
+  return rc;
+#endif
+}
+
+/*
+** Make sure pMem->z points to a writable allocation of at least n bytes.
+**
+** If the bPreserve argument is true, then copy of the content of
+** pMem->z into the new allocation.  pMem must be either a string or
+** blob if bPreserve is true.  If bPreserve is false, any prior content
+** in pMem->z is discarded.
+*/
+SQLITE_NOINLINE int sqlite3VdbeMemGrow(Mem *pMem, int n, int bPreserve){
+  assert( sqlite3VdbeCheckMemInvariants(pMem) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  testcase( pMem->db==0 );
+
+  /* If the bPreserve flag is set to true, then the memory cell must already
+  ** contain a valid string or blob value.  */
+  assert( bPreserve==0 || pMem->flags&(MEM_Blob|MEM_Str) );
+  testcase( bPreserve && pMem->z==0 );
+
+  assert( pMem->szMalloc==0
+       || (pMem->flags==MEM_Undefined 
+           && pMem->szMalloc<=sqlite3DbMallocSize(pMem->db,pMem->zMalloc))
+       || pMem->szMalloc==sqlite3DbMallocSize(pMem->db,pMem->zMalloc));
+  if( pMem->szMalloc>0 && bPreserve && pMem->z==pMem->zMalloc ){
+    if( pMem->db ){
+      pMem->z = pMem->zMalloc = sqlite3DbReallocOrFree(pMem->db, pMem->z, n);
+    }else{
+      pMem->zMalloc = sqlite3Realloc(pMem->z, n);
+      if( pMem->zMalloc==0 ) sqlite3_free(pMem->z);
+      pMem->z = pMem->zMalloc;
+    }
+    bPreserve = 0;
+  }else{
+    if( pMem->szMalloc>0 ) sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
+    pMem->zMalloc = sqlite3DbMallocRaw(pMem->db, n);
+  }
+  if( pMem->zMalloc==0 ){
+    sqlite3VdbeMemSetNull(pMem);
+    pMem->z = 0;
+    pMem->szMalloc = 0;
+    return SQLITE_NOMEM_BKPT;
+  }else{
+    pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->zMalloc);
+  }
+
+  if( bPreserve && pMem->z ){
+    assert( pMem->z!=pMem->zMalloc );
+    memcpy(pMem->zMalloc, pMem->z, pMem->n);
+  }
+  if( (pMem->flags&MEM_Dyn)!=0 ){
+    assert( pMem->xDel!=0 && pMem->xDel!=SQLITE_DYNAMIC );
+    pMem->xDel((void *)(pMem->z));
+  }
+
+  pMem->z = pMem->zMalloc;
+  pMem->flags &= ~(MEM_Dyn|MEM_Ephem|MEM_Static);
+  return SQLITE_OK;
+}
+
+/*
+** Change the pMem->zMalloc allocation to be at least szNew bytes.
+** If pMem->zMalloc already meets or exceeds the requested size, this
+** routine is a no-op.
+**
+** Any prior string or blob content in the pMem object may be discarded.
+** The pMem->xDel destructor is called, if it exists.  Though MEM_Str
+** and MEM_Blob values may be discarded, MEM_Int, MEM_Real, MEM_IntReal,
+** and MEM_Null values are preserved.
+**
+** Return SQLITE_OK on success or an error code (probably SQLITE_NOMEM)
+** if unable to complete the resizing.
+*/
+int sqlite3VdbeMemClearAndResize(Mem *pMem, int szNew){
+  assert( CORRUPT_DB || szNew>0 );
+  assert( (pMem->flags & MEM_Dyn)==0 || pMem->szMalloc==0 );
+  if( pMem->szMalloc<szNew ){
+    return sqlite3VdbeMemGrow(pMem, szNew, 0);
+  }
+  assert( (pMem->flags & MEM_Dyn)==0 );
+  pMem->z = pMem->zMalloc;
+  pMem->flags &= (MEM_Null|MEM_Int|MEM_Real|MEM_IntReal);
+  return SQLITE_OK;
+}
+
+/*
+** If pMem is already a string, detect if it is a zero-terminated
+** string, or make it into one if possible, and mark it as such.
+**
+** This is an optimization.  Correct operation continues even if
+** this routine is a no-op.
+*/
+void sqlite3VdbeMemZeroTerminateIfAble(Mem *pMem){
+  if( (pMem->flags & (MEM_Str|MEM_Term|MEM_Ephem|MEM_Static))!=MEM_Str ){
+    /* pMem must be a string, and it cannot be an ephemeral or static string */
+    return;
+  }
+  if( pMem->enc!=SQLITE_UTF8 ) return;
+  if( NEVER(pMem->z==0) ) return;
+  if( pMem->flags & MEM_Dyn ){
+    if( pMem->xDel==sqlite3_free
+     && sqlite3_msize(pMem->z) >= (u64)(pMem->n+1)
+    ){
+      pMem->z[pMem->n] = 0;
+      pMem->flags |= MEM_Term;
+      return;
+    }
+    if( pMem->xDel==sqlite3RCStrUnref ){
+      /* Blindly assume that all RCStr objects are zero-terminated */
+      pMem->flags |= MEM_Term;
+      return;
+    }
+  }else if( pMem->szMalloc >= pMem->n+1 ){
+    pMem->z[pMem->n] = 0;
+    pMem->flags |= MEM_Term;
+    return;
+  }
+}
+
+/*
+** It is already known that pMem contains an unterminated string.
+** Add the zero terminator.
+**
+** Three bytes of zero are added.  In this way, there is guaranteed
+** to be a double-zero byte at an even byte boundary in order to
+** terminate a UTF16 string, even if the initial size of the buffer
+** is an odd number of bytes.
+*/
+static SQLITE_NOINLINE int vdbeMemAddTerminator(Mem *pMem){
+  if( sqlite3VdbeMemGrow(pMem, pMem->n+3, 1) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  pMem->z[pMem->n] = 0;
+  pMem->z[pMem->n+1] = 0;
+  pMem->z[pMem->n+2] = 0;
+  pMem->flags |= MEM_Term;
+  return SQLITE_OK;
+}
+
+/*
+** Change pMem so that its MEM_Str or MEM_Blob value is stored in
+** MEM.zMalloc, where it can be safely written.
+**
+** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
+*/
+int sqlite3VdbeMemMakeWriteable(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  if( (pMem->flags & (MEM_Str|MEM_Blob))!=0 ){
+    if( ExpandBlob(pMem) ) return SQLITE_NOMEM;
+    if( pMem->szMalloc==0 || pMem->z!=pMem->zMalloc ){
+      int rc = vdbeMemAddTerminator(pMem);
+      if( rc ) return rc;
+    }
+  }
+  pMem->flags &= ~MEM_Ephem;
+#ifdef SQLITE_DEBUG
+  pMem->pScopyFrom = 0;
+#endif
+
+  return SQLITE_OK;
+}
+
+/*
+** If the given Mem* has a zero-filled tail, turn it into an ordinary
+** blob stored in dynamically allocated space.
+*/
+#ifndef SQLITE_OMIT_INCRBLOB
+int sqlite3VdbeMemExpandBlob(Mem *pMem){
+  int nByte;
+  assert( pMem!=0 );
+  assert( pMem->flags & MEM_Zero );
+  assert( (pMem->flags&MEM_Blob)!=0 || MemNullNochng(pMem) );
+  testcase( sqlite3_value_nochange(pMem) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+
+  /* Set nByte to the number of bytes required to store the expanded blob. */
+  nByte = pMem->n + pMem->u.nZero;
+  if( nByte<=0 ){
+    if( (pMem->flags & MEM_Blob)==0 ) return SQLITE_OK;
+    nByte = 1;
+  }
+  if( sqlite3VdbeMemGrow(pMem, nByte, 1) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  assert( pMem->z!=0 );
+  assert( sqlite3DbMallocSize(pMem->db,pMem->z) >= nByte );
+
+  memset(&pMem->z[pMem->n], 0, pMem->u.nZero);
+  pMem->n += pMem->u.nZero;
+  pMem->flags &= ~(MEM_Zero|MEM_Term);
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** Make sure the given Mem is \u0000 terminated.
+*/
+int sqlite3VdbeMemNulTerminate(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  testcase( (pMem->flags & (MEM_Term|MEM_Str))==(MEM_Term|MEM_Str) );
+  testcase( (pMem->flags & (MEM_Term|MEM_Str))==0 );
+  if( (pMem->flags & (MEM_Term|MEM_Str))!=MEM_Str ){
+    return SQLITE_OK;   /* Nothing to do */
+  }else{
+    return vdbeMemAddTerminator(pMem);
+  }
+}
+
+/*
+** Add MEM_Str to the set of representations for the given Mem.  This
+** routine is only called if pMem is a number of some kind, not a NULL
+** or a BLOB.
+**
+** Existing representations MEM_Int, MEM_Real, or MEM_IntReal are invalidated
+** if bForce is true but are retained if bForce is false.
+**
+** A MEM_Null value will never be passed to this function. This function is
+** used for converting values to text for returning to the user (i.e. via
+** sqlite3_value_text()), or for ensuring that values to be used as btree
+** keys are strings. In the former case a NULL pointer is returned the
+** user and the latter is an internal programming error.
+*/
+int sqlite3VdbeMemStringify(Mem *pMem, u8 enc, u8 bForce){
+  const int nByte = 32;
+
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !(pMem->flags&MEM_Zero) );
+  assert( !(pMem->flags&(MEM_Str|MEM_Blob)) );
+  assert( pMem->flags&(MEM_Int|MEM_Real|MEM_IntReal) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+
+  if( sqlite3VdbeMemClearAndResize(pMem, nByte) ){
+    pMem->enc = 0;
+    return SQLITE_NOMEM_BKPT;
+  }
+
+  vdbeMemRenderNum(nByte, pMem->z, pMem);
+  assert( pMem->z!=0 );
+  assert( pMem->n==(int)sqlite3Strlen30NN(pMem->z) );
+  pMem->enc = SQLITE_UTF8;
+  pMem->flags |= MEM_Str|MEM_Term;
+  if( bForce ) pMem->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal);
+  sqlite3VdbeChangeEncoding(pMem, enc);
+  return SQLITE_OK;
+}
+
+/*
+** Memory cell pMem contains the context of an aggregate function.
+** This routine calls the finalize method for that function.  The
+** result of the aggregate is stored back into pMem.
+**
+** Return SQLITE_ERROR if the finalizer reports an error.  SQLITE_OK
+** otherwise.
+*/
+int sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){
+  sqlite3_context ctx;
+  Mem t;
+  assert( pFunc!=0 );
+  assert( pMem!=0 );
+  assert( pMem->db!=0 );
+  assert( pFunc->xFinalize!=0 );
+  assert( (pMem->flags & MEM_Null)!=0 || pFunc==pMem->u.pDef );
+  assert( sqlite3_mutex_held(pMem->db->mutex) );
+  memset(&ctx, 0, sizeof(ctx));
+  memset(&t, 0, sizeof(t));
+  t.flags = MEM_Null;
+  t.db = pMem->db;
+  ctx.pOut = &t;
+  ctx.pMem = pMem;
+  ctx.pFunc = pFunc;
+  ctx.enc = ENC(t.db);
+  pFunc->xFinalize(&ctx); /* IMP: R-24505-23230 */
+  assert( (pMem->flags & MEM_Dyn)==0 );
+  if( pMem->szMalloc>0 ) sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
+  memcpy(pMem, &t, sizeof(t));
+  return ctx.isError;
+}
+
+/*
+** Memory cell pAccum contains the context of an aggregate function.
+** This routine calls the xValue method for that function and stores
+** the results in memory cell pMem.
+**
+** SQLITE_ERROR is returned if xValue() reports an error. SQLITE_OK 
+** otherwise.
+*/
+#ifndef SQLITE_OMIT_WINDOWFUNC
+int sqlite3VdbeMemAggValue(Mem *pAccum, Mem *pOut, FuncDef *pFunc){
+  sqlite3_context ctx;
+  assert( pFunc!=0 );
+  assert( pFunc->xValue!=0 );
+  assert( (pAccum->flags & MEM_Null)!=0 || pFunc==pAccum->u.pDef );
+  assert( pAccum->db!=0 );
+  assert( sqlite3_mutex_held(pAccum->db->mutex) );
+  memset(&ctx, 0, sizeof(ctx));
+  sqlite3VdbeMemSetNull(pOut);
+  ctx.pOut = pOut;
+  ctx.pMem = pAccum;
+  ctx.pFunc = pFunc;
+  ctx.enc = ENC(pAccum->db);
+  pFunc->xValue(&ctx);
+  return ctx.isError;
+}
+#endif /* SQLITE_OMIT_WINDOWFUNC */
+
+/*
+** If the memory cell contains a value that must be freed by
+** invoking the external callback in Mem.xDel, then this routine
+** will free that value.  It also sets Mem.flags to MEM_Null.
+**
+** This is a helper routine for sqlite3VdbeMemSetNull() and
+** for sqlite3VdbeMemRelease().  Use those other routines as the
+** entry point for releasing Mem resources.
+*/
+static SQLITE_NOINLINE void vdbeMemClearExternAndSetNull(Mem *p){
+  assert( p->db==0 || sqlite3_mutex_held(p->db->mutex) );
+  assert( VdbeMemDynamic(p) );
+  if( p->flags&MEM_Agg ){
+    sqlite3VdbeMemFinalize(p, p->u.pDef);
+    assert( (p->flags & MEM_Agg)==0 );
+    testcase( p->flags & MEM_Dyn );
+  }
+  if( p->flags&MEM_Dyn ){
+    assert( p->xDel!=SQLITE_DYNAMIC && p->xDel!=0 );
+    p->xDel((void *)p->z);
+  }
+  p->flags = MEM_Null;
+}
+
+/*
+** Release memory held by the Mem p, both external memory cleared
+** by p->xDel and memory in p->zMalloc.
+**
+** This is a helper routine invoked by sqlite3VdbeMemRelease() in
+** the unusual case where there really is memory in p that needs
+** to be freed.
+*/
+static SQLITE_NOINLINE void vdbeMemClear(Mem *p){
+  if( VdbeMemDynamic(p) ){
+    vdbeMemClearExternAndSetNull(p);
+  }
+  if( p->szMalloc ){
+    sqlite3DbFreeNN(p->db, p->zMalloc);
+    p->szMalloc = 0;
+  }
+  p->z = 0;
+}
+
+/*
+** Release any memory resources held by the Mem.  Both the memory that is
+** free by Mem.xDel and the Mem.zMalloc allocation are freed.
+**
+** Use this routine prior to clean up prior to abandoning a Mem, or to
+** reset a Mem back to its minimum memory utilization.
+**
+** Use sqlite3VdbeMemSetNull() to release just the Mem.xDel space
+** prior to inserting new content into the Mem.
+*/
+void sqlite3VdbeMemRelease(Mem *p){
+  assert( sqlite3VdbeCheckMemInvariants(p) );
+  if( VdbeMemDynamic(p) || p->szMalloc ){
+    vdbeMemClear(p);
+  }
+}
+
+/* Like sqlite3VdbeMemRelease() but faster for cases where we
+** know in advance that the Mem is not MEM_Dyn or MEM_Agg.
+*/
+void sqlite3VdbeMemReleaseMalloc(Mem *p){
+  assert( !VdbeMemDynamic(p) );
+  if( p->szMalloc ) vdbeMemClear(p);
+}
+
+/*
+** Return some kind of integer value which is the best we can do
+** at representing the value that *pMem describes as an integer.
+** If pMem is an integer, then the value is exact.  If pMem is
+** a floating-point then the value returned is the integer part.
+** If pMem is a string or blob, then we make an attempt to convert
+** it into an integer and return that.  If pMem represents an
+** an SQL-NULL value, return 0.
+**
+** If pMem represents a string value, its encoding might be changed.
+*/
+static SQLITE_NOINLINE i64 memIntValue(const Mem *pMem){
+  i64 value = 0;
+  sqlite3Atoi64(pMem->z, &value, pMem->n, pMem->enc);
+  return value;
+}
+i64 sqlite3VdbeIntValue(const Mem *pMem){
+  int flags;
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+  flags = pMem->flags;
+  if( flags & (MEM_Int|MEM_IntReal) ){
+    testcase( flags & MEM_IntReal );
+    return pMem->u.i;
+  }else if( flags & MEM_Real ){
+    return sqlite3RealToI64(pMem->u.r);
+  }else if( (flags & (MEM_Str|MEM_Blob))!=0 && pMem->z!=0 ){
+    return memIntValue(pMem);
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Return the best representation of pMem that we can get into a
+** double.  If pMem is already a double or an integer, return its
+** value.  If it is a string or blob, try to convert it to a double.
+** If it is a NULL, return 0.0.
+*/
+static SQLITE_NOINLINE double memRealValue(Mem *pMem){
+  /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+  double val = (double)0;
+  sqlite3AtoF(pMem->z, &val, pMem->n, pMem->enc);
+  return val;
+}
+double sqlite3VdbeRealValue(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+  if( pMem->flags & MEM_Real ){
+    return pMem->u.r;
+  }else if( pMem->flags & (MEM_Int|MEM_IntReal) ){
+    testcase( pMem->flags & MEM_IntReal );
+    return (double)pMem->u.i;
+  }else if( pMem->flags & (MEM_Str|MEM_Blob) ){
+    return memRealValue(pMem);
+  }else{
+    /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
+    return (double)0;
+  }
+}
+
+/*
+** Return 1 if pMem represents true, and return 0 if pMem represents false.
+** Return the value ifNull if pMem is NULL.  
+*/
+int sqlite3VdbeBooleanValue(Mem *pMem, int ifNull){
+  testcase( pMem->flags & MEM_IntReal );
+  if( pMem->flags & (MEM_Int|MEM_IntReal) ) return pMem->u.i!=0;
+  if( pMem->flags & MEM_Null ) return ifNull;
+  return sqlite3VdbeRealValue(pMem)!=0.0;
+}
+
+/*
+** The MEM structure is already a MEM_Real or MEM_IntReal. Try to 
+** make it a MEM_Int if we can.
+*/
+void sqlite3VdbeIntegerAffinity(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->flags & (MEM_Real|MEM_IntReal) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+  if( pMem->flags & MEM_IntReal ){
+    MemSetTypeFlag(pMem, MEM_Int);
+  }else{
+    i64 ix = sqlite3RealToI64(pMem->u.r);
+
+    /* Only mark the value as an integer if
+    **
+    **    (1) the round-trip conversion real->int->real is a no-op, and
+    **    (2) The integer is neither the largest nor the smallest
+    **        possible integer (ticket #3922)
+    **
+    ** The second and third terms in the following conditional enforces
+    ** the second condition under the assumption that addition overflow causes
+    ** values to wrap around.
+    */
+    if( pMem->u.r==ix && ix>SMALLEST_INT64 && ix<LARGEST_INT64 ){
+      pMem->u.i = ix;
+      MemSetTypeFlag(pMem, MEM_Int);
+    }
+  }
+}
+
+/*
+** Convert pMem to type integer.  Invalidate any prior representations.
+*/
+int sqlite3VdbeMemIntegerify(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+  pMem->u.i = sqlite3VdbeIntValue(pMem);
+  MemSetTypeFlag(pMem, MEM_Int);
+  return SQLITE_OK;
+}
+
+/*
+** Convert pMem so that it is of type MEM_Real.
+** Invalidate any prior representations.
+*/
+int sqlite3VdbeMemRealify(Mem *pMem){
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( EIGHT_BYTE_ALIGNMENT(pMem) );
+
+  pMem->u.r = sqlite3VdbeRealValue(pMem);
+  MemSetTypeFlag(pMem, MEM_Real);
+  return SQLITE_OK;
+}
+
+/* Compare a floating point value to an integer.  Return true if the two
+** values are the same within the precision of the floating point value.
+**
+** This function assumes that i was obtained by assignment from r1.
+**
+** For some versions of GCC on 32-bit machines, if you do the more obvious
+** comparison of "r1==(double)i" you sometimes get an answer of false even
+** though the r1 and (double)i values are bit-for-bit the same.
+*/
+int sqlite3RealSameAsInt(double r1, sqlite3_int64 i){
+  double r2 = (double)i;
+  return r1==0.0
+      || (memcmp(&r1, &r2, sizeof(r1))==0
+          && i >= -2251799813685248LL && i < 2251799813685248LL);
+}
+
+/* Convert a floating point value to its closest integer.  Do so in
+** a way that avoids 'outside the range of representable values' warnings
+** from UBSAN.
+*/
+i64 sqlite3RealToI64(double r){
+  if( r<-9223372036854774784.0 ) return SMALLEST_INT64;
+  if( r>+9223372036854774784.0 ) return LARGEST_INT64;
+  return (i64)r;
+}
+
+/*
+** Convert pMem so that it has type MEM_Real or MEM_Int.
+** Invalidate any prior representations.
+**
+** Every effort is made to force the conversion, even if the input
+** is a string that does not look completely like a number.  Convert
+** as much of the string as we can and ignore the rest.
+*/
+int sqlite3VdbeMemNumerify(Mem *pMem){
+  assert( pMem!=0 );
+  testcase( pMem->flags & MEM_Int );
+  testcase( pMem->flags & MEM_Real );
+  testcase( pMem->flags & MEM_IntReal );
+  testcase( pMem->flags & MEM_Null );
+  if( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null))==0 ){
+    int rc;
+    sqlite3_int64 ix;
+    assert( (pMem->flags & (MEM_Blob|MEM_Str))!=0 );
+    assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+    rc = sqlite3AtoF(pMem->z, &pMem->u.r, pMem->n, pMem->enc);
+    if( ((rc==0 || rc==1) && sqlite3Atoi64(pMem->z, &ix, pMem->n, pMem->enc)<=1)
+     || sqlite3RealSameAsInt(pMem->u.r, (ix = sqlite3RealToI64(pMem->u.r)))
+    ){
+      pMem->u.i = ix;
+      MemSetTypeFlag(pMem, MEM_Int);
+    }else{
+      MemSetTypeFlag(pMem, MEM_Real);
+    }
+  }
+  assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null))!=0 );
+  pMem->flags &= ~(MEM_Str|MEM_Blob|MEM_Zero);
+  return SQLITE_OK;
+}
+
+/*
+** Cast the datatype of the value in pMem according to the affinity
+** "aff".  Casting is different from applying affinity in that a cast
+** is forced.  In other words, the value is converted into the desired
+** affinity even if that results in loss of data.  This routine is
+** used (for example) to implement the SQL "cast()" operator.
+*/
+int sqlite3VdbeMemCast(Mem *pMem, u8 aff, u8 encoding){
+  if( pMem->flags & MEM_Null ) return SQLITE_OK;
+  switch( aff ){
+    case SQLITE_AFF_BLOB: {   /* Really a cast to BLOB */
+      if( (pMem->flags & MEM_Blob)==0 ){
+        sqlite3ValueApplyAffinity(pMem, SQLITE_AFF_TEXT, encoding);
+        assert( pMem->flags & MEM_Str || pMem->db->mallocFailed );
+        if( pMem->flags & MEM_Str ) MemSetTypeFlag(pMem, MEM_Blob);
+      }else{
+        pMem->flags &= ~(MEM_TypeMask&~MEM_Blob);
+      }
+      break;
+    }
+    case SQLITE_AFF_NUMERIC: {
+      sqlite3VdbeMemNumerify(pMem);
+      break;
+    }
+    case SQLITE_AFF_INTEGER: {
+      sqlite3VdbeMemIntegerify(pMem);
+      break;
+    }
+    case SQLITE_AFF_REAL: {
+      sqlite3VdbeMemRealify(pMem);
+      break;
+    }
+    default: {
+      int rc;
+      assert( aff==SQLITE_AFF_TEXT );
+      assert( MEM_Str==(MEM_Blob>>3) );
+      pMem->flags |= (pMem->flags&MEM_Blob)>>3;
+      sqlite3ValueApplyAffinity(pMem, SQLITE_AFF_TEXT, encoding);
+      assert( pMem->flags & MEM_Str || pMem->db->mallocFailed );
+      pMem->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal|MEM_Blob|MEM_Zero);
+      if( encoding!=SQLITE_UTF8 ) pMem->n &= ~1;
+      rc = sqlite3VdbeChangeEncoding(pMem, encoding);
+      if( rc ) return rc;
+      sqlite3VdbeMemZeroTerminateIfAble(pMem);
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Initialize bulk memory to be a consistent Mem object.
+**
+** The minimum amount of initialization feasible is performed.
+*/
+void sqlite3VdbeMemInit(Mem *pMem, sqlite3 *db, u16 flags){
+  assert( (flags & ~MEM_TypeMask)==0 );
+  pMem->flags = flags;
+  pMem->db = db;
+  pMem->szMalloc = 0;
+}
+
+
+/*
+** Delete any previous value and set the value stored in *pMem to NULL.
+**
+** This routine calls the Mem.xDel destructor to dispose of values that
+** require the destructor.  But it preserves the Mem.zMalloc memory allocation.
+** To free all resources, use sqlite3VdbeMemRelease(), which both calls this
+** routine to invoke the destructor and deallocates Mem.zMalloc.
+**
+** Use this routine to reset the Mem prior to insert a new value.
+**
+** Use sqlite3VdbeMemRelease() to complete erase the Mem prior to abandoning it.
+*/
+void sqlite3VdbeMemSetNull(Mem *pMem){
+  if( VdbeMemDynamic(pMem) ){
+    vdbeMemClearExternAndSetNull(pMem);
+  }else{
+    pMem->flags = MEM_Null;
+  }
+}
+void sqlite3ValueSetNull(sqlite3_value *p){
+  sqlite3VdbeMemSetNull((Mem*)p); 
+}
+
+/*
+** Delete any previous value and set the value to be a BLOB of length
+** n containing all zeros.
+*/
+#ifndef SQLITE_OMIT_INCRBLOB
+void sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
+  sqlite3VdbeMemRelease(pMem);
+  pMem->flags = MEM_Blob|MEM_Zero;
+  pMem->n = 0;
+  if( n<0 ) n = 0;
+  pMem->u.nZero = n;
+  pMem->enc = SQLITE_UTF8;
+  pMem->z = 0;
+}
+#else
+int sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
+  int nByte = n>0?n:1;
+  if( sqlite3VdbeMemGrow(pMem, nByte, 0) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+  assert( pMem->z!=0 );
+  assert( sqlite3DbMallocSize(pMem->db, pMem->z)>=nByte );
+  memset(pMem->z, 0, nByte);
+  pMem->n = n>0?n:0;
+  pMem->flags = MEM_Blob;
+  pMem->enc = SQLITE_UTF8;
+  return SQLITE_OK;
+}
+#endif
+
+/*
+** The pMem is known to contain content that needs to be destroyed prior
+** to a value change.  So invoke the destructor, then set the value to
+** a 64-bit integer.
+*/
+static SQLITE_NOINLINE void vdbeReleaseAndSetInt64(Mem *pMem, i64 val){
+  sqlite3VdbeMemSetNull(pMem);
+  pMem->u.i = val;
+  pMem->flags = MEM_Int;
+}
+
+/*
+** Delete any previous value and set the value stored in *pMem to val,
+** manifest type INTEGER.
+*/
+void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
+  if( VdbeMemDynamic(pMem) ){
+    vdbeReleaseAndSetInt64(pMem, val);
+  }else{
+    pMem->u.i = val;
+    pMem->flags = MEM_Int;
+  }
+}
+
+/* A no-op destructor */
+void sqlite3NoopDestructor(void *p){ UNUSED_PARAMETER(p); }
+
+/*
+** Set the value stored in *pMem should already be a NULL.
+** Also store a pointer to go with it.
+*/
+void sqlite3VdbeMemSetPointer(
+  Mem *pMem,
+  void *pPtr,
+  const char *zPType,
+  void (*xDestructor)(void*)
+){
+  assert( pMem->flags==MEM_Null );
+  vdbeMemClear(pMem);
+  pMem->u.zPType = zPType ? zPType : "";
+  pMem->z = pPtr;
+  pMem->flags = MEM_Null|MEM_Dyn|MEM_Subtype|MEM_Term;
+  pMem->eSubtype = 'p';
+  pMem->xDel = xDestructor ? xDestructor : sqlite3NoopDestructor;
+}
+
+#ifndef SQLITE_OMIT_FLOATING_POINT
+/*
+** Delete any previous value and set the value stored in *pMem to val,
+** manifest type REAL.
+*/
+void sqlite3VdbeMemSetDouble(Mem *pMem, double val){
+  sqlite3VdbeMemSetNull(pMem);
+  if( !sqlite3IsNaN(val) ){
+    pMem->u.r = val;
+    pMem->flags = MEM_Real;
+  }
+}
+#endif
+
+#ifdef SQLITE_DEBUG
+/*
+** Return true if the Mem holds a RowSet object.  This routine is intended
+** for use inside of assert() statements.
+*/
+int sqlite3VdbeMemIsRowSet(const Mem *pMem){
+  return (pMem->flags&(MEM_Blob|MEM_Dyn))==(MEM_Blob|MEM_Dyn)
+         && pMem->xDel==sqlite3RowSetDelete;
+}
+#endif
+
+/*
+** Delete any previous value and set the value of pMem to be an
+** empty boolean index.
+**
+** Return SQLITE_OK on success and SQLITE_NOMEM if a memory allocation
+** error occurs.
+*/
+int sqlite3VdbeMemSetRowSet(Mem *pMem){
+  sqlite3 *db = pMem->db;
+  RowSet *p;
+  assert( db!=0 );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  sqlite3VdbeMemRelease(pMem);
+  p = sqlite3RowSetInit(db);
+  if( p==0 ) return SQLITE_NOMEM;
+  pMem->z = (char*)p;
+  pMem->flags = MEM_Blob|MEM_Dyn;
+  pMem->xDel = sqlite3RowSetDelete;
+  return SQLITE_OK;
+}
+
+/*
+** Return true if the Mem object contains a TEXT or BLOB that is
+** too large - whose size exceeds SQLITE_MAX_LENGTH.
+*/
+int sqlite3VdbeMemTooBig(Mem *p){
+  assert( p->db!=0 );
+  if( p->flags & (MEM_Str|MEM_Blob) ){
+    int n = p->n;
+    if( p->flags & MEM_Zero ){
+      n += p->u.nZero;
+    }
+    return n>p->db->aLimit[SQLITE_LIMIT_LENGTH];
+  }
+  return 0; 
+}
+
+#ifdef SQLITE_DEBUG
+/*
+** This routine prepares a memory cell for modification by breaking
+** its link to a shallow copy and by marking any current shallow
+** copies of this cell as invalid.
+**
+** This is used for testing and debugging only - to help ensure that shallow
+** copies (created by OP_SCopy) are not misused.
+*/
+void sqlite3VdbeMemAboutToChange(Vdbe *pVdbe, Mem *pMem){
+  int i;
+  Mem *pX;
+  for(i=1, pX=pVdbe->aMem+1; i<pVdbe->nMem; i++, pX++){
+    if( pX->pScopyFrom==pMem ){
+      u16 mFlags;
+      if( pVdbe->db->flags & SQLITE_VdbeTrace ){
+        sqlite3DebugPrintf("Invalidate R[%d] due to change in R[%d]\n",
+          (int)(pX - pVdbe->aMem), (int)(pMem - pVdbe->aMem));
+      }
+      /* If pX is marked as a shallow copy of pMem, then try to verify that
+      ** no significant changes have been made to pX since the OP_SCopy.
+      ** A significant change would indicated a missed call to this
+      ** function for pX.  Minor changes, such as adding or removing a
+      ** dual type, are allowed, as long as the underlying value is the
+      ** same. */
+      mFlags = pMem->flags & pX->flags & pX->mScopyFlags;
+      assert( (mFlags&(MEM_Int|MEM_IntReal))==0 || pMem->u.i==pX->u.i );
+      
+      /* pMem is the register that is changing.  But also mark pX as
+      ** undefined so that we can quickly detect the shallow-copy error */
+      pX->flags = MEM_Undefined;
+      pX->pScopyFrom = 0;
+    }
+  }
+  pMem->pScopyFrom = 0;
+}
+#endif /* SQLITE_DEBUG */
+
+/*
+** Make an shallow copy of pFrom into pTo.  Prior contents of
+** pTo are freed.  The pFrom->z field is not duplicated.  If
+** pFrom->z is used, then pTo->z points to the same thing as pFrom->z
+** and flags gets srcType (either MEM_Ephem or MEM_Static).
+*/
+static SQLITE_NOINLINE void vdbeClrCopy(Mem *pTo, const Mem *pFrom, int eType){
+  vdbeMemClearExternAndSetNull(pTo);
+  assert( !VdbeMemDynamic(pTo) );
+  sqlite3VdbeMemShallowCopy(pTo, pFrom, eType);
+}
+void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
+  assert( !sqlite3VdbeMemIsRowSet(pFrom) );
+  assert( pTo->db==pFrom->db );
+  if( VdbeMemDynamic(pTo) ){ vdbeClrCopy(pTo,pFrom,srcType); return; }
+  memcpy(pTo, pFrom, MEMCELLSIZE);
+  if( (pFrom->flags&MEM_Static)==0 ){
+    pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
+    assert( srcType==MEM_Ephem || srcType==MEM_Static );
+    pTo->flags |= srcType;
+  }
+}
+
+/*
+** Make a full copy of pFrom into pTo.  Prior contents of pTo are
+** freed before the copy is made.
+*/
+int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
+  int rc = SQLITE_OK;
+
+  assert( !sqlite3VdbeMemIsRowSet(pFrom) );
+  if( VdbeMemDynamic(pTo) ) vdbeMemClearExternAndSetNull(pTo);
+  memcpy(pTo, pFrom, MEMCELLSIZE);
+  pTo->flags &= ~MEM_Dyn;
+  if( pTo->flags&(MEM_Str|MEM_Blob) ){
+    if( 0==(pFrom->flags&MEM_Static) ){
+      pTo->flags |= MEM_Ephem;
+      rc = sqlite3VdbeMemMakeWriteable(pTo);
+    }
+  }
+
+  return rc;
+}
+
+/*
+** Transfer the contents of pFrom to pTo. Any existing value in pTo is
+** freed. If pFrom contains ephemeral data, a copy is made.
+**
+** pFrom contains an SQL NULL when this routine returns.
+*/
+void sqlite3VdbeMemMove(Mem *pTo, Mem *pFrom){
+  assert( pFrom->db==0 || sqlite3_mutex_held(pFrom->db->mutex) );
+  assert( pTo->db==0 || sqlite3_mutex_held(pTo->db->mutex) );
+  assert( pFrom->db==0 || pTo->db==0 || pFrom->db==pTo->db );
+
+  sqlite3VdbeMemRelease(pTo);
+  memcpy(pTo, pFrom, sizeof(Mem));
+  pFrom->flags = MEM_Null;
+  pFrom->szMalloc = 0;
+}
+
+/*
+** Change the value of a Mem to be a string or a BLOB.
+**
+** The memory management strategy depends on the value of the xDel
+** parameter. If the value passed is SQLITE_TRANSIENT, then the 
+** string is copied into a (possibly existing) buffer managed by the 
+** Mem structure. Otherwise, any existing buffer is freed and the
+** pointer copied.
+**
+** If the string is too large (if it exceeds the SQLITE_LIMIT_LENGTH
+** size limit) then no memory allocation occurs.  If the string can be
+** stored without allocating memory, then it is.  If a memory allocation
+** is required to store the string, then value of pMem is unchanged.  In
+** either case, SQLITE_TOOBIG is returned.
+**
+** The "enc" parameter is the text encoding for the string, or zero
+** to store a blob.
+**
+** If n is negative, then the string consists of all bytes up to but
+** excluding the first zero character.  The n parameter must be
+** non-negative for blobs.
+*/
+int sqlite3VdbeMemSetStr(
+  Mem *pMem,          /* Memory cell to set to string value */
+  const char *z,      /* String pointer */
+  i64 n,              /* Bytes in string, or negative */
+  u8 enc,             /* Encoding of z.  0 for BLOBs */
+  void (*xDel)(void*) /* Destructor function */
+){
+  i64 nByte = n;      /* New value for pMem->n */
+  int iLimit;         /* Maximum allowed string or blob size */
+  u16 flags;          /* New value for pMem->flags */
+
+  assert( pMem!=0 );
+  assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  assert( enc!=0 || n>=0 );
+
+  /* If z is a NULL pointer, set pMem to contain an SQL NULL. */
+  if( !z ){
+    sqlite3VdbeMemSetNull(pMem);
+    return SQLITE_OK;
+  }
+
+  if( pMem->db ){
+    iLimit = pMem->db->aLimit[SQLITE_LIMIT_LENGTH];
+  }else{
+    iLimit = SQLITE_MAX_LENGTH;
+  }
+  if( nByte<0 ){
+    assert( enc!=0 );
+    if( enc==SQLITE_UTF8 ){
+      nByte = strlen(z);
+    }else{
+      for(nByte=0; nByte<=iLimit && (z[nByte] | z[nByte+1]); nByte+=2){}
+    }
+    flags= MEM_Str|MEM_Term;
+  }else if( enc==0 ){
+    flags = MEM_Blob;
+    enc = SQLITE_UTF8;
+  }else{
+    flags = MEM_Str;
+  }
+  if( nByte>iLimit ){
+    if( xDel && xDel!=SQLITE_TRANSIENT ){
+      if( xDel==SQLITE_DYNAMIC ){
+        sqlite3DbFree(pMem->db, (void*)z);
+      }else{
+        xDel((void*)z);
+      }
+    }
+    sqlite3VdbeMemSetNull(pMem);
+    return sqlite3ErrorToParser(pMem->db, SQLITE_TOOBIG);
+  }
+
+  /* The following block sets the new values of Mem.z and Mem.xDel. It
+  ** also sets a flag in local variable "flags" to indicate the memory
+  ** management (one of MEM_Dyn or MEM_Static).
+  */
+  if( xDel==SQLITE_TRANSIENT ){
+    i64 nAlloc = nByte;
+    if( flags&MEM_Term ){
+      nAlloc += (enc==SQLITE_UTF8?1:2);
+    }
+    testcase( nAlloc==0 );
+    testcase( nAlloc==31 );
+    testcase( nAlloc==32 );
+    if( sqlite3VdbeMemClearAndResize(pMem, (int)MAX(nAlloc,32)) ){
+      return SQLITE_NOMEM_BKPT;
+    }
+    memcpy(pMem->z, z, nAlloc);
+  }else{
+    sqlite3VdbeMemRelease(pMem);
+    pMem->z = (char *)z;
+    if( xDel==SQLITE_DYNAMIC ){
+      pMem->zMalloc = pMem->z;
+      pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->zMalloc);
+    }else{
+      pMem->xDel = xDel;
+      flags |= ((xDel==SQLITE_STATIC)?MEM_Static:MEM_Dyn);
+    }
+  }
+
+  pMem->n = (int)(nByte & 0x7fffffff);
+  pMem->flags = flags;
+  pMem->enc = enc;
+
+#ifndef SQLITE_OMIT_UTF16
+  if( enc>SQLITE_UTF8 && sqlite3VdbeMemHandleBom(pMem) ){
+    return SQLITE_NOMEM_BKPT;
+  }
+#endif
+
+
+  return SQLITE_OK;
+}
+
+/*
+** Move data out of a btree key or data field and into a Mem structure.
+** The data is payload from the entry that pCur is currently pointing
+** to.  offset and amt determine what portion of the data or key to retrieve.
+** The result is written into the pMem element.
+**
+** The pMem object must have been initialized.  This routine will use
+** pMem->zMalloc to hold the content from the btree, if possible.  New
+** pMem->zMalloc space will be allocated if necessary.  The calling routine
+** is responsible for making sure that the pMem object is eventually
+** destroyed.
+**
+** If this routine fails for any reason (malloc returns NULL or unable
+** to read from the disk) then the pMem is left in an inconsistent state.
+*/
+int sqlite3VdbeMemFromBtree(
+  BtCursor *pCur,   /* Cursor pointing at record to retrieve. */
+  u32 offset,       /* Offset from the start of data to return bytes from. */
+  u32 amt,          /* Number of bytes to return. */
+  Mem *pMem         /* OUT: Return data in this Mem structure. */
+){
+  int rc;
+  pMem->flags = MEM_Null;
+  if( sqlite3BtreeMaxRecordSize(pCur)<offset+amt ){
+    return SQLITE_CORRUPT_BKPT;
+  }
+  if( SQLITE_OK==(rc = sqlite3VdbeMemClearAndResize(pMem, amt+1)) ){
+    rc = sqlite3BtreePayload(pCur, offset, amt, pMem->z);
+    if( rc==SQLITE_OK ){
+      pMem->z[amt] = 0;   /* Overrun area used when reading malformed records */
+      pMem->flags = MEM_Blob;
+      pMem->n = (int)amt;
+    }else{
+      sqlite3VdbeMemRelease(pMem);
+    }
+  }
+  return rc;
+}
+int sqlite3VdbeMemFromBtreeZeroOffset(
+  BtCursor *pCur,   /* Cursor pointing at record to retrieve. */
+  u32 amt,          /* Number of bytes to return. */
+  Mem *pMem         /* OUT: Return data in this Mem structure. */
+){
+  u32 available = 0;  /* Number of bytes available on the local btree page */
+  int rc = SQLITE_OK; /* Return code */
+
+  assert( sqlite3BtreeCursorIsValid(pCur) );
+  assert( !VdbeMemDynamic(pMem) );
+
+  /* Note: the calls to BtreeKeyFetch() and DataFetch() below assert() 
+  ** that both the BtShared and database handle mutexes are held. */
+  assert( !sqlite3VdbeMemIsRowSet(pMem) );
+  pMem->z = (char *)sqlite3BtreePayloadFetch(pCur, &available);
+  assert( pMem->z!=0 );
+
+  if( amt<=available ){
+    pMem->flags = MEM_Blob|MEM_Ephem;
+    pMem->n = (int)amt;
+  }else{
+    rc = sqlite3VdbeMemFromBtree(pCur, 0, amt, pMem);
+  }
+
+  return rc;
+}
+
+/*
+** The pVal argument is known to be a value other than NULL.
+** Convert it into a string with encoding enc and return a pointer
+** to a zero-terminated version of that string.
+*/
+static SQLITE_NOINLINE const void *valueToText(sqlite3_value* pVal, u8 enc){
+  assert( pVal!=0 );
+  assert( pVal->db==0 || sqlite3_mutex_held(pVal->db->mutex) );
+  assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );
+  assert( !sqlite3VdbeMemIsRowSet(pVal) );
+  assert( (pVal->flags & (MEM_Null))==0 );
+  if( pVal->flags & (MEM_Blob|MEM_Str) ){
+    if( ExpandBlob(pVal) ) return 0;
+    pVal->flags |= MEM_Str;
+    if( pVal->enc != (enc & ~SQLITE_UTF16_ALIGNED) ){
+      sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
+    }
+    if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&SQLITE_PTR_TO_INT(pVal->z)) ){
+      assert( (pVal->flags & (MEM_Ephem|MEM_Static))!=0 );
+      if( sqlite3VdbeMemMakeWriteable(pVal)!=SQLITE_OK ){
+        return 0;
+      }
+    }
+    sqlite3VdbeMemNulTerminate(pVal); /* IMP: R-31275-44060 */
+  }else{
+    sqlite3VdbeMemStringify(pVal, enc, 0);
+    assert( 0==(1&SQLITE_PTR_TO_INT(pVal->z)) );
+  }
+  assert(pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) || pVal->db==0
+              || pVal->db->mallocFailed );
+  if( pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) ){
+    assert( sqlite3VdbeMemValidStrRep(pVal) );
+    return pVal->z;
+  }else{
+    return 0;
+  }
+}
+
+/* This function is only available internally, it is not part of the
+** external API. It works in a similar way to sqlite3_value_text(),
+** except the data returned is in the encoding specified by the second
+** parameter, which must be one of SQLITE_UTF16BE, SQLITE_UTF16LE or
+** SQLITE_UTF8.
+**
+** (2006-02-16:)  The enc value can be or-ed with SQLITE_UTF16_ALIGNED.
+** If that is the case, then the result must be aligned on an even byte
+** boundary.
+*/
+const void *sqlite3ValueText(sqlite3_value* pVal, u8 enc){
+  if( !pVal ) return 0;
+  assert( pVal->db==0 || sqlite3_mutex_held(pVal->db->mutex) );
+  assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );
+  assert( !sqlite3VdbeMemIsRowSet(pVal) );
+  if( (pVal->flags&(MEM_Str|MEM_Term))==(MEM_Str|MEM_Term) && pVal->enc==enc ){
+    assert( sqlite3VdbeMemValidStrRep(pVal) );
+    return pVal->z;
+  }
+  if( pVal->flags&MEM_Null ){
+    return 0;
+  }
+  return valueToText(pVal, enc);
+}
+
+/* Return true if sqlit3_value object pVal is a string or blob value
+** that uses the destructor specified in the second argument.
+**
+** TODO:  Maybe someday promote this interface into a published API so
+** that third-party extensions can get access to it?
+*/
+int sqlite3ValueIsOfClass(const sqlite3_value *pVal, void(*xFree)(void*)){
+  if( ALWAYS(pVal!=0)
+   && ALWAYS((pVal->flags & (MEM_Str|MEM_Blob))!=0)
+   && (pVal->flags & MEM_Dyn)!=0
+   && pVal->xDel==xFree
+  ){
+    return 1;
+  }else{
+    return 0;
+  }
+}
+
+/*
+** Create a new sqlite3_value object.
+*/
+sqlite3_value *sqlite3ValueNew(sqlite3 *db){
+  Mem *p = sqlite3DbMallocZero(db, sizeof(*p));
+  if( p ){
+    p->flags = MEM_Null;
+    p->db = db;
+  }
+  return p;
+}
+
+/*
+** Context object passed by sqlite3Stat4ProbeSetValue() through to 
+** valueNew(). See comments above valueNew() for details.
+*/
+struct ValueNewStat4Ctx {
+  Parse *pParse;
+  Index *pIdx;
+  UnpackedRecord **ppRec;
+  int iVal;
+};
+
+/*
+** Allocate and return a pointer to a new sqlite3_value object. If
+** the second argument to this function is NULL, the object is allocated
+** by calling sqlite3ValueNew().
+**
+** Otherwise, if the second argument is non-zero, then this function is 
+** being called indirectly by sqlite3Stat4ProbeSetValue(). If it has not
+** already been allocated, allocate the UnpackedRecord structure that 
+** that function will return to its caller here. Then return a pointer to
+** an sqlite3_value within the UnpackedRecord.a[] array.
+*/
+static sqlite3_value *valueNew(sqlite3 *db, struct ValueNewStat4Ctx *p){
+#ifdef SQLITE_ENABLE_STAT4
+  if( p ){
+    UnpackedRecord *pRec = p->ppRec[0];
+
+    if( pRec==0 ){
+      Index *pIdx = p->pIdx;      /* Index being probed */
+      int nByte;                  /* Bytes of space to allocate */
+      int i;                      /* Counter variable */
+      int nCol = pIdx->nColumn;   /* Number of index columns including rowid */
+  
+      nByte = sizeof(Mem) * nCol + ROUND8(sizeof(UnpackedRecord));
+      pRec = (UnpackedRecord*)sqlite3DbMallocZero(db, nByte);
+      if( pRec ){
+        pRec->pKeyInfo = sqlite3KeyInfoOfIndex(p->pParse, pIdx);
+        if( pRec->pKeyInfo ){
+          assert( pRec->pKeyInfo->nAllField==nCol );
+          assert( pRec->pKeyInfo->enc==ENC(db) );
+          pRec->aMem = (Mem *)((u8*)pRec + ROUND8(sizeof(UnpackedRecord)));
+          for(i=0; i<nCol; i++){
+            pRec->aMem[i].flags = MEM_Null;
+            pRec->aMem[i].db = db;
+          }
+        }else{
+          sqlite3DbFreeNN(db, pRec);
+          pRec = 0;
+        }
+      }
+      if( pRec==0 ) return 0;
+      p->ppRec[0] = pRec;
+    }
+  
+    pRec->nField = p->iVal+1;
+    sqlite3VdbeMemSetNull(&pRec->aMem[p->iVal]);
+    return &pRec->aMem[p->iVal];
+  }
+#else
+  UNUSED_PARAMETER(p);
+#endif /* defined(SQLITE_ENABLE_STAT4) */
+  return sqlite3ValueNew(db);
+}
+
+/*
+** The expression object indicated by the second argument is guaranteed
+** to be a scalar SQL function. If
+**
+**   * all function arguments are SQL literals,
+**   * one of the SQLITE_FUNC_CONSTANT or _SLOCHNG function flags is set, and
+**   * the SQLITE_FUNC_NEEDCOLL function flag is not set,
+**
+** then this routine attempts to invoke the SQL function. Assuming no
+** error occurs, output parameter (*ppVal) is set to point to a value 
+** object containing the result before returning SQLITE_OK.
+**
+** Affinity aff is applied to the result of the function before returning.
+** If the result is a text value, the sqlite3_value object uses encoding 
+** enc.
+**
+** If the conditions above are not met, this function returns SQLITE_OK
+** and sets (*ppVal) to NULL. Or, if an error occurs, (*ppVal) is set to
+** NULL and an SQLite error code returned.
+*/
+#ifdef SQLITE_ENABLE_STAT4
+static int valueFromFunction(
+  sqlite3 *db,                    /* The database connection */
+  const Expr *p,                  /* The expression to evaluate */
+  u8 enc,                         /* Encoding to use */
+  u8 aff,                         /* Affinity to use */
+  sqlite3_value **ppVal,          /* Write the new value here */
+  struct ValueNewStat4Ctx *pCtx   /* Second argument for valueNew() */
+){
+  sqlite3_context ctx;            /* Context object for function invocation */
+  sqlite3_value **apVal = 0;      /* Function arguments */
+  int nVal = 0;                   /* Size of apVal[] array */
+  FuncDef *pFunc = 0;             /* Function definition */
+  sqlite3_value *pVal = 0;        /* New value */
+  int rc = SQLITE_OK;             /* Return code */
+  ExprList *pList = 0;            /* Function arguments */
+  int i;                          /* Iterator variable */
+
+  assert( pCtx!=0 );
+  assert( (p->flags & EP_TokenOnly)==0 );
+  assert( ExprUseXList(p) );
+  pList = p->x.pList;
+  if( pList ) nVal = pList->nExpr;
+  assert( !ExprHasProperty(p, EP_IntValue) );
+  pFunc = sqlite3FindFunction(db, p->u.zToken, nVal, enc, 0);
+#ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
+  if( pFunc==0 ) return SQLITE_OK;
+#endif
+  assert( pFunc );
+  if( (pFunc->funcFlags & (SQLITE_FUNC_CONSTANT|SQLITE_FUNC_SLOCHNG))==0
+   || (pFunc->funcFlags & (SQLITE_FUNC_NEEDCOLL|SQLITE_FUNC_RUNONLY))!=0
+  ){
+    return SQLITE_OK;
+  }
+
+  if( pList ){
+    apVal = (sqlite3_value**)sqlite3DbMallocZero(db, sizeof(apVal[0]) * nVal);
+    if( apVal==0 ){
+      rc = SQLITE_NOMEM_BKPT;
+      goto value_from_function_out;
+    }
+    for(i=0; i<nVal; i++){
+      rc = sqlite3ValueFromExpr(db, pList->a[i].pExpr, enc, aff, &apVal[i]);
+      if( apVal[i]==0 || rc!=SQLITE_OK ) goto value_from_function_out;
+    }
+  }
+
+  pVal = valueNew(db, pCtx);
+  if( pVal==0 ){
+    rc = SQLITE_NOMEM_BKPT;
+    goto value_from_function_out;
+  }
+
+  memset(&ctx, 0, sizeof(ctx));
+  ctx.pOut = pVal;
+  ctx.pFunc = pFunc;
+  ctx.enc = ENC(db);
+  pFunc->xSFunc(&ctx, nVal, apVal);
+  if( ctx.isError ){
+    rc = ctx.isError;
+    sqlite3ErrorMsg(pCtx->pParse, "%s", sqlite3_value_text(pVal));
+  }else{
+    sqlite3ValueApplyAffinity(pVal, aff, SQLITE_UTF8);
+    assert( rc==SQLITE_OK );
+    rc = sqlite3VdbeChangeEncoding(pVal, enc);
+    if( NEVER(rc==SQLITE_OK && sqlite3VdbeMemTooBig(pVal)) ){
+      rc = SQLITE_TOOBIG;
+      pCtx->pParse->nErr++;
+    }
+  }
+
+ value_from_function_out:
+  if( rc!=SQLITE_OK ){
+    pVal = 0;
+    pCtx->pParse->rc = rc;
+  }
+  if( apVal ){
+    for(i=0; i<nVal; i++){
+      sqlite3ValueFree(apVal[i]);
+    }
+    sqlite3DbFreeNN(db, apVal);
+  }
+
+  *ppVal = pVal;
+  return rc;
+}
+#else
+# define valueFromFunction(a,b,c,d,e,f) SQLITE_OK
+#endif /* defined(SQLITE_ENABLE_STAT4) */
+
+/*
+** Extract a value from the supplied expression in the manner described
+** above sqlite3ValueFromExpr(). Allocate the sqlite3_value object
+** using valueNew().
+**
+** If pCtx is NULL and an error occurs after the sqlite3_value object
+** has been allocated, it is freed before returning. Or, if pCtx is not
+** NULL, it is assumed that the caller will free any allocated object
+** in all cases.
+*/
+static int valueFromExpr(
+  sqlite3 *db,                    /* The database connection */
+  const Expr *pExpr,              /* The expression to evaluate */
+  u8 enc,                         /* Encoding to use */
+  u8 affinity,                    /* Affinity to use */
+  sqlite3_value **ppVal,          /* Write the new value here */
+  struct ValueNewStat4Ctx *pCtx   /* Second argument for valueNew() */
+){
+  int op;
+  char *zVal = 0;
+  sqlite3_value *pVal = 0;
+  int negInt = 1;
+  const char *zNeg = "";
+  int rc = SQLITE_OK;
+
+  assert( pExpr!=0 );
+  while( (op = pExpr->op)==TK_UPLUS || op==TK_SPAN ) pExpr = pExpr->pLeft;
+  if( op==TK_REGISTER ) op = pExpr->op2;
+
+  /* Compressed expressions only appear when parsing the DEFAULT clause
+  ** on a table column definition, and hence only when pCtx==0.  This
+  ** check ensures that an EP_TokenOnly expression is never passed down
+  ** into valueFromFunction(). */
+  assert( (pExpr->flags & EP_TokenOnly)==0 || pCtx==0 );
+
+  if( op==TK_CAST ){
+    u8 aff;
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+    aff = sqlite3AffinityType(pExpr->u.zToken,0);
+    rc = valueFromExpr(db, pExpr->pLeft, enc, aff, ppVal, pCtx);
+    testcase( rc!=SQLITE_OK );
+    if( *ppVal ){
+#ifdef SQLITE_ENABLE_STAT4
+      rc = ExpandBlob(*ppVal);
+#else
+      /* zero-blobs only come from functions, not literal values.  And
+      ** functions are only processed under STAT4 */
+      assert( (ppVal[0][0].flags & MEM_Zero)==0 );
+#endif
+      sqlite3VdbeMemCast(*ppVal, aff, enc);
+      sqlite3ValueApplyAffinity(*ppVal, affinity, enc);
+    }
+    return rc;
+  }
+
+  /* Handle negative integers in a single step.  This is needed in the
+  ** case when the value is -9223372036854775808.
+  */
+  if( op==TK_UMINUS
+   && (pExpr->pLeft->op==TK_INTEGER || pExpr->pLeft->op==TK_FLOAT) ){
+    pExpr = pExpr->pLeft;
+    op = pExpr->op;
+    negInt = -1;
+    zNeg = "-";
+  }
+
+  if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
+    pVal = valueNew(db, pCtx);
+    if( pVal==0 ) goto no_mem;
+    if( ExprHasProperty(pExpr, EP_IntValue) ){
+      sqlite3VdbeMemSetInt64(pVal, (i64)pExpr->u.iValue*negInt);
+    }else{
+      zVal = sqlite3MPrintf(db, "%s%s", zNeg, pExpr->u.zToken);
+      if( zVal==0 ) goto no_mem;
+      sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
+    }
+    if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_BLOB ){
+      sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, SQLITE_UTF8);
+    }else{
+      sqlite3ValueApplyAffinity(pVal, affinity, SQLITE_UTF8);
+    }
+    assert( (pVal->flags & MEM_IntReal)==0 );
+    if( pVal->flags & (MEM_Int|MEM_IntReal|MEM_Real) ){
+      testcase( pVal->flags & MEM_Int );
+      testcase( pVal->flags & MEM_Real );
+      pVal->flags &= ~MEM_Str;
+    }
+    if( enc!=SQLITE_UTF8 ){
+      rc = sqlite3VdbeChangeEncoding(pVal, enc);
+    }
+  }else if( op==TK_UMINUS ) {
+    /* This branch happens for multiple negative signs.  Ex: -(-5) */
+    if( SQLITE_OK==valueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal,pCtx) 
+     && pVal!=0
+    ){
+      sqlite3VdbeMemNumerify(pVal);
+      if( pVal->flags & MEM_Real ){
+        pVal->u.r = -pVal->u.r;
+      }else if( pVal->u.i==SMALLEST_INT64 ){
+#ifndef SQLITE_OMIT_FLOATING_POINT
+        pVal->u.r = -(double)SMALLEST_INT64;
+#else
+        pVal->u.r = LARGEST_INT64;
+#endif
+        MemSetTypeFlag(pVal, MEM_Real);
+      }else{
+        pVal->u.i = -pVal->u.i;
+      }
+      sqlite3ValueApplyAffinity(pVal, affinity, enc);
+    }
+  }else if( op==TK_NULL ){
+    pVal = valueNew(db, pCtx);
+    if( pVal==0 ) goto no_mem;
+    sqlite3VdbeMemSetNull(pVal);
+  }
+#ifndef SQLITE_OMIT_BLOB_LITERAL
+  else if( op==TK_BLOB ){
+    int nVal;
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+    assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
+    assert( pExpr->u.zToken[1]=='\'' );
+    pVal = valueNew(db, pCtx);
+    if( !pVal ) goto no_mem;
+    zVal = &pExpr->u.zToken[2];
+    nVal = sqlite3Strlen30(zVal)-1;
+    assert( zVal[nVal]=='\'' );
+    sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
+                         0, SQLITE_DYNAMIC);
+  }
+#endif
+#ifdef SQLITE_ENABLE_STAT4
+  else if( op==TK_FUNCTION && pCtx!=0 ){
+    rc = valueFromFunction(db, pExpr, enc, affinity, &pVal, pCtx);
+  }
+#endif
+  else if( op==TK_TRUEFALSE ){
+    assert( !ExprHasProperty(pExpr, EP_IntValue) );
+    pVal = valueNew(db, pCtx);
+    if( pVal ){
+      pVal->flags = MEM_Int;
+      pVal->u.i = pExpr->u.zToken[4]==0;
+      sqlite3ValueApplyAffinity(pVal, affinity, enc);
+    }
+  }
+
+  *ppVal = pVal;
+  return rc;
+
+no_mem:
+#ifdef SQLITE_ENABLE_STAT4
+  if( pCtx==0 || NEVER(pCtx->pParse->nErr==0) )
+#endif
+    sqlite3OomFault(db);
+  sqlite3DbFree(db, zVal);
+  assert( *ppVal==0 );
+#ifdef SQLITE_ENABLE_STAT4
+  if( pCtx==0 ) sqlite3ValueFree(pVal);
+#else
+  assert( pCtx==0 ); sqlite3ValueFree(pVal);
+#endif
+  return SQLITE_NOMEM_BKPT;
+}
+
+/*
+** Create a new sqlite3_value object, containing the value of pExpr.
+**
+** This only works for very simple expressions that consist of one constant
+** token (i.e. "5", "5.1", "'a string'"). If the expression can
+** be converted directly into a value, then the value is allocated and
+** a pointer written to *ppVal. The caller is responsible for deallocating
+** the value by passing it to sqlite3ValueFree() later on. If the expression
+** cannot be converted to a value, then *ppVal is set to NULL.
+*/
+int sqlite3ValueFromExpr(
+  sqlite3 *db,              /* The database connection */
+  const Expr *pExpr,        /* The expression to evaluate */
+  u8 enc,                   /* Encoding to use */
+  u8 affinity,              /* Affinity to use */
+  sqlite3_value **ppVal     /* Write the new value here */
+){
+  return pExpr ? valueFromExpr(db, pExpr, enc, affinity, ppVal, 0) : 0;
+}
+
+#ifdef SQLITE_ENABLE_STAT4
+/*
+** Attempt to extract a value from pExpr and use it to construct *ppVal.
+**
+** If pAlloc is not NULL, then an UnpackedRecord object is created for
+** pAlloc if one does not exist and the new value is added to the
+** UnpackedRecord object.
+**
+** A value is extracted in the following cases:
+**
+**  * (pExpr==0). In this case the value is assumed to be an SQL NULL,
+**
+**  * The expression is a bound variable, and this is a reprepare, or
+**
+**  * The expression is a literal value.
+**
+** On success, *ppVal is made to point to the extracted value.  The caller
+** is responsible for ensuring that the value is eventually freed.
+*/
+static int stat4ValueFromExpr(
+  Parse *pParse,                  /* Parse context */
+  Expr *pExpr,                    /* The expression to extract a value from */
+  u8 affinity,                    /* Affinity to use */
+  struct ValueNewStat4Ctx *pAlloc,/* How to allocate space.  Or NULL */
+  sqlite3_value **ppVal           /* OUT: New value object (or NULL) */
+){
+  int rc = SQLITE_OK;
+  sqlite3_value *pVal = 0;
+  sqlite3 *db = pParse->db;
+
+  /* Skip over any TK_COLLATE nodes */
+  pExpr = sqlite3ExprSkipCollate(pExpr);
+
+  assert( pExpr==0 || pExpr->op!=TK_REGISTER || pExpr->op2!=TK_VARIABLE );
+  if( !pExpr ){
+    pVal = valueNew(db, pAlloc);
+    if( pVal ){
+      sqlite3VdbeMemSetNull((Mem*)pVal);
+    }
+  }else if( pExpr->op==TK_VARIABLE && (db->flags & SQLITE_EnableQPSG)==0 ){
+    Vdbe *v;
+    int iBindVar = pExpr->iColumn;
+    sqlite3VdbeSetVarmask(pParse->pVdbe, iBindVar);
+    if( (v = pParse->pReprepare)!=0 ){
+      pVal = valueNew(db, pAlloc);
+      if( pVal ){
+        rc = sqlite3VdbeMemCopy((Mem*)pVal, &v->aVar[iBindVar-1]);
+        sqlite3ValueApplyAffinity(pVal, affinity, ENC(db));
+        pVal->db = pParse->db;
+      }
+    }
+  }else{
+    rc = valueFromExpr(db, pExpr, ENC(db), affinity, &pVal, pAlloc);
+  }
+
+  assert( pVal==0 || pVal->db==db );
+  *ppVal = pVal;
+  return rc;
+}
+
+/*
+** This function is used to allocate and populate UnpackedRecord 
+** structures intended to be compared against sample index keys stored 
+** in the sqlite_stat4 table.
+**
+** A single call to this function populates zero or more fields of the
+** record starting with field iVal (fields are numbered from left to
+** right starting with 0). A single field is populated if:
+**
+**  * (pExpr==0). In this case the value is assumed to be an SQL NULL,
+**
+**  * The expression is a bound variable, and this is a reprepare, or
+**
+**  * The sqlite3ValueFromExpr() function is able to extract a value 
+**    from the expression (i.e. the expression is a literal value).
+**
+** Or, if pExpr is a TK_VECTOR, one field is populated for each of the
+** vector components that match either of the two latter criteria listed
+** above.
+**
+** Before any value is appended to the record, the affinity of the 
+** corresponding column within index pIdx is applied to it. Before
+** this function returns, output parameter *pnExtract is set to the
+** number of values appended to the record.
+**
+** When this function is called, *ppRec must either point to an object
+** allocated by an earlier call to this function, or must be NULL. If it
+** is NULL and a value can be successfully extracted, a new UnpackedRecord
+** is allocated (and *ppRec set to point to it) before returning.
+**
+** Unless an error is encountered, SQLITE_OK is returned. It is not an
+** error if a value cannot be extracted from pExpr. If an error does
+** occur, an SQLite error code is returned.
+*/
+int sqlite3Stat4ProbeSetValue(
+  Parse *pParse,                  /* Parse context */
+  Index *pIdx,                    /* Index being probed */
+  UnpackedRecord **ppRec,         /* IN/OUT: Probe record */
+  Expr *pExpr,                    /* The expression to extract a value from */
+  int nElem,                      /* Maximum number of values to append */
+  int iVal,                       /* Array element to populate */
+  int *pnExtract                  /* OUT: Values appended to the record */
+){
+  int rc = SQLITE_OK;
+  int nExtract = 0;
+
+  if( pExpr==0 || pExpr->op!=TK_SELECT ){
+    int i;
+    struct ValueNewStat4Ctx alloc;
+
+    alloc.pParse = pParse;
+    alloc.pIdx = pIdx;
+    alloc.ppRec = ppRec;
+
+    for(i=0; i<nElem; i++){
+      sqlite3_value *pVal = 0;
+      Expr *pElem = (pExpr ? sqlite3VectorFieldSubexpr(pExpr, i) : 0);
+      u8 aff = sqlite3IndexColumnAffinity(pParse->db, pIdx, iVal+i);
+      alloc.iVal = iVal+i;
+      rc = stat4ValueFromExpr(pParse, pElem, aff, &alloc, &pVal);
+      if( !pVal ) break;
+      nExtract++;
+    }
+  }
+
+  *pnExtract = nExtract;
+  return rc;
+}
+
+/*
+** Attempt to extract a value from expression pExpr using the methods
+** as described for sqlite3Stat4ProbeSetValue() above. 
+**
+** If successful, set *ppVal to point to a new value object and return 
+** SQLITE_OK. If no value can be extracted, but no other error occurs
+** (e.g. OOM), return SQLITE_OK and set *ppVal to NULL. Or, if an error
+** does occur, return an SQLite error code. The final value of *ppVal
+** is undefined in this case.
+*/
+int sqlite3Stat4ValueFromExpr(
+  Parse *pParse,                  /* Parse context */
+  Expr *pExpr,                    /* The expression to extract a value from */
+  u8 affinity,                    /* Affinity to use */
+  sqlite3_value **ppVal           /* OUT: New value object (or NULL) */
+){
+  return stat4ValueFromExpr(pParse, pExpr, affinity, 0, ppVal);
+}
+
+/*
+** Extract the iCol-th column from the nRec-byte record in pRec.  Write
+** the column value into *ppVal.  If *ppVal is initially NULL then a new
+** sqlite3_value object is allocated.
+**
+** If *ppVal is initially NULL then the caller is responsible for 
+** ensuring that the value written into *ppVal is eventually freed.
+*/
+int sqlite3Stat4Column(
+  sqlite3 *db,                    /* Database handle */
+  const void *pRec,               /* Pointer to buffer containing record */
+  int nRec,                       /* Size of buffer pRec in bytes */
+  int iCol,                       /* Column to extract */
+  sqlite3_value **ppVal           /* OUT: Extracted value */
+){
+  u32 t = 0;                      /* a column type code */
+  int nHdr;                       /* Size of the header in the record */
+  int iHdr;                       /* Next unread header byte */
+  int iField;                     /* Next unread data byte */
+  int szField = 0;                /* Size of the current data field */
+  int i;                          /* Column index */
+  u8 *a = (u8*)pRec;              /* Typecast byte array */
+  Mem *pMem = *ppVal;             /* Write result into this Mem object */
+
+  assert( iCol>0 );
+  iHdr = getVarint32(a, nHdr);
+  if( nHdr>nRec || iHdr>=nHdr ) return SQLITE_CORRUPT_BKPT;
+  iField = nHdr;
+  for(i=0; i<=iCol; i++){
+    iHdr += getVarint32(&a[iHdr], t);
+    testcase( iHdr==nHdr );
+    testcase( iHdr==nHdr+1 );
+    if( iHdr>nHdr ) return SQLITE_CORRUPT_BKPT;
+    szField = sqlite3VdbeSerialTypeLen(t);
+    iField += szField;
+  }
+  testcase( iField==nRec );
+  testcase( iField==nRec+1 );
+  if( iField>nRec ) return SQLITE_CORRUPT_BKPT;
+  if( pMem==0 ){
+    pMem = *ppVal = sqlite3ValueNew(db);
+    if( pMem==0 ) return SQLITE_NOMEM_BKPT;
+  }
+  sqlite3VdbeSerialGet(&a[iField-szField], t, pMem);
+  pMem->enc = ENC(db);
+  return SQLITE_OK;
+}
+
+/*
+** Unless it is NULL, the argument must be an UnpackedRecord object returned
+** by an earlier call to sqlite3Stat4ProbeSetValue(). This call deletes
+** the object.
+*/
+void sqlite3Stat4ProbeFree(UnpackedRecord *pRec){
+  if( pRec ){
+    int i;
+    int nCol = pRec->pKeyInfo->nAllField;
+    Mem *aMem = pRec->aMem;
+    sqlite3 *db = aMem[0].db;
+    for(i=0; i<nCol; i++){
+      sqlite3VdbeMemRelease(&aMem[i]);
+    }
+    sqlite3KeyInfoUnref(pRec->pKeyInfo);
+    sqlite3DbFreeNN(db, pRec);
+  }
+}
+#endif /* ifdef SQLITE_ENABLE_STAT4 */
+
+/*
+** Change the string value of an sqlite3_value object
+*/
+void sqlite3ValueSetStr(
+  sqlite3_value *v,     /* Value to be set */
+  int n,                /* Length of string z */
+  const void *z,        /* Text of the new string */
+  u8 enc,               /* Encoding to use */
+  void (*xDel)(void*)   /* Destructor for the string */
+){
+  if( v ) sqlite3VdbeMemSetStr((Mem *)v, z, n, enc, xDel);
+}
+
+/*
+** Free an sqlite3_value object
+*/
+void sqlite3ValueFree(sqlite3_value *v){
+  if( !v ) return;
+  sqlite3VdbeMemRelease((Mem *)v);
+  sqlite3DbFreeNN(((Mem*)v)->db, v);
+}
+
+/*
+** The sqlite3ValueBytes() routine returns the number of bytes in the
+** sqlite3_value object assuming that it uses the encoding "enc".
+** The valueBytes() routine is a helper function.
+*/
+static SQLITE_NOINLINE int valueBytes(sqlite3_value *pVal, u8 enc){
+  return valueToText(pVal, enc)!=0 ? pVal->n : 0;
+}
+int sqlite3ValueBytes(sqlite3_value *pVal, u8 enc){
+  Mem *p = (Mem*)pVal;
+  assert( (p->flags & MEM_Null)==0 || (p->flags & (MEM_Str|MEM_Blob))==0 );
+  if( (p->flags & MEM_Str)!=0 && pVal->enc==enc ){
+    return p->n;
+  }
+  if( (p->flags & MEM_Str)!=0 && enc!=SQLITE_UTF8 && pVal->enc!=SQLITE_UTF8 ){
+    return p->n;
+  }
+  if( (p->flags & MEM_Blob)!=0 ){
+    if( p->flags & MEM_Zero ){
+      return p->n + p->u.nZero;
+    }else{
+      return p->n;
+    }
+  }
+  if( p->flags & MEM_Null ) return 0;
+  return valueBytes(pVal, enc);
+}