sl@0: /*
sl@0: ** 2004 May 26
sl@0: **
sl@0: ** The author disclaims copyright to this source code.  In place of
sl@0: ** a legal notice, here is a blessing:
sl@0: **
sl@0: **    May you do good and not evil.
sl@0: **    May you find forgiveness for yourself and forgive others.
sl@0: **    May you share freely, never taking more than you give.
sl@0: **
sl@0: *************************************************************************
sl@0: **
sl@0: ** This file contains code use to manipulate "Mem" structure.  A "Mem"
sl@0: ** stores a single value in the VDBE.  Mem is an opaque structure visible
sl@0: ** only within the VDBE.  Interface routines refer to a Mem using the
sl@0: ** name sqlite_value
sl@0: **
sl@0: ** $Id: vdbemem.c,v 1.121 2008/08/01 20:10:09 drh Exp $
sl@0: */
sl@0: #include "sqliteInt.h"
sl@0: #include <ctype.h>
sl@0: #include "vdbeInt.h"
sl@0: 
sl@0: /*
sl@0: ** Call sqlite3VdbeMemExpandBlob() on the supplied value (type Mem*)
sl@0: ** P if required.
sl@0: */
sl@0: #define expandBlob(P) (((P)->flags&MEM_Zero)?sqlite3VdbeMemExpandBlob(P):0)
sl@0: 
sl@0: /*
sl@0: ** If pMem is an object with a valid string representation, this routine
sl@0: ** ensures the internal encoding for the string representation is
sl@0: ** 'desiredEnc', one of SQLITE_UTF8, SQLITE_UTF16LE or SQLITE_UTF16BE.
sl@0: **
sl@0: ** If pMem is not a string object, or the encoding of the string
sl@0: ** representation is already stored using the requested encoding, then this
sl@0: ** routine is a no-op.
sl@0: **
sl@0: ** SQLITE_OK is returned if the conversion is successful (or not required).
sl@0: ** SQLITE_NOMEM may be returned if a malloc() fails during conversion
sl@0: ** between formats.
sl@0: */
sl@0: int sqlite3VdbeChangeEncoding(Mem *pMem, int desiredEnc){
sl@0:   int rc;
sl@0:   if( !(pMem->flags&MEM_Str) || pMem->enc==desiredEnc ){
sl@0:     return SQLITE_OK;
sl@0:   }
sl@0:   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0: #ifdef SQLITE_OMIT_UTF16
sl@0:   return SQLITE_ERROR;
sl@0: #else
sl@0: 
sl@0:   /* MemTranslate() may return SQLITE_OK or SQLITE_NOMEM. If NOMEM is returned,
sl@0:   ** then the encoding of the value may not have changed.
sl@0:   */
sl@0:   rc = sqlite3VdbeMemTranslate(pMem, desiredEnc);
sl@0:   assert(rc==SQLITE_OK    || rc==SQLITE_NOMEM);
sl@0:   assert(rc==SQLITE_OK    || pMem->enc!=desiredEnc);
sl@0:   assert(rc==SQLITE_NOMEM || pMem->enc==desiredEnc);
sl@0:   return rc;
sl@0: #endif
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Make sure pMem->z points to a writable allocation of at least 
sl@0: ** n bytes.
sl@0: **
sl@0: ** If the memory cell currently contains string or blob data
sl@0: ** and the third argument passed to this function is true, the 
sl@0: ** current content of the cell is preserved. Otherwise, it may
sl@0: ** be discarded.  
sl@0: **
sl@0: ** This function sets the MEM_Dyn flag and clears any xDel callback.
sl@0: ** It also clears MEM_Ephem and MEM_Static. If the preserve flag is 
sl@0: ** not set, Mem.n is zeroed.
sl@0: */
sl@0: int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve){
sl@0:   assert( 1 >=
sl@0:     ((pMem->zMalloc && pMem->zMalloc==pMem->z) ? 1 : 0) +
sl@0:     (((pMem->flags&MEM_Dyn)&&pMem->xDel) ? 1 : 0) + 
sl@0:     ((pMem->flags&MEM_Ephem) ? 1 : 0) + 
sl@0:     ((pMem->flags&MEM_Static) ? 1 : 0)
sl@0:   );
sl@0: 
sl@0:   if( n<32 ) n = 32;
sl@0:   if( sqlite3DbMallocSize(pMem->db, pMem->zMalloc)<n ){
sl@0:     if( preserve && pMem->z==pMem->zMalloc ){
sl@0:       pMem->z = pMem->zMalloc = sqlite3DbReallocOrFree(pMem->db, pMem->z, n);
sl@0:       if( !pMem->z ){
sl@0:         pMem->flags = MEM_Null;
sl@0:       }
sl@0:       preserve = 0;
sl@0:     }else{
sl@0:       sqlite3DbFree(pMem->db, pMem->zMalloc);
sl@0:       pMem->zMalloc = sqlite3DbMallocRaw(pMem->db, n);
sl@0:     }
sl@0:   }
sl@0: 
sl@0:   if( preserve && pMem->z && pMem->zMalloc && pMem->z!=pMem->zMalloc ){
sl@0:     memcpy(pMem->zMalloc, pMem->z, pMem->n);
sl@0:   }
sl@0:   if( pMem->flags&MEM_Dyn && pMem->xDel ){
sl@0:     pMem->xDel((void *)(pMem->z));
sl@0:   }
sl@0: 
sl@0:   pMem->z = pMem->zMalloc;
sl@0:   pMem->flags &= ~(MEM_Ephem|MEM_Static);
sl@0:   pMem->xDel = 0;
sl@0:   return (pMem->z ? SQLITE_OK : SQLITE_NOMEM);
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Make the given Mem object MEM_Dyn.  In other words, make it so
sl@0: ** that any TEXT or BLOB content is stored in memory obtained from
sl@0: ** malloc().  In this way, we know that the memory is safe to be
sl@0: ** overwritten or altered.
sl@0: **
sl@0: ** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
sl@0: */
sl@0: int sqlite3VdbeMemMakeWriteable(Mem *pMem){
sl@0:   int f;
sl@0:   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0:   expandBlob(pMem);
sl@0:   f = pMem->flags;
sl@0:   if( (f&(MEM_Str|MEM_Blob)) && pMem->z!=pMem->zMalloc ){
sl@0:     if( sqlite3VdbeMemGrow(pMem, pMem->n + 2, 1) ){
sl@0:       return SQLITE_NOMEM;
sl@0:     }
sl@0:     pMem->z[pMem->n] = 0;
sl@0:     pMem->z[pMem->n+1] = 0;
sl@0:     pMem->flags |= MEM_Term;
sl@0:   }
sl@0: 
sl@0:   return SQLITE_OK;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** If the given Mem* has a zero-filled tail, turn it into an ordinary
sl@0: ** blob stored in dynamically allocated space.
sl@0: */
sl@0: #ifndef SQLITE_OMIT_INCRBLOB
sl@0: int sqlite3VdbeMemExpandBlob(Mem *pMem){
sl@0:   if( pMem->flags & MEM_Zero ){
sl@0:     int nByte;
sl@0:     assert( pMem->flags&MEM_Blob );
sl@0:     assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0: 
sl@0:     /* Set nByte to the number of bytes required to store the expanded blob. */
sl@0:     nByte = pMem->n + pMem->u.i;
sl@0:     if( nByte<=0 ){
sl@0:       nByte = 1;
sl@0:     }
sl@0:     if( sqlite3VdbeMemGrow(pMem, nByte, 1) ){
sl@0:       return SQLITE_NOMEM;
sl@0:     }
sl@0: 
sl@0:     memset(&pMem->z[pMem->n], 0, pMem->u.i);
sl@0:     pMem->n += pMem->u.i;
sl@0:     pMem->flags &= ~(MEM_Zero|MEM_Term);
sl@0:   }
sl@0:   return SQLITE_OK;
sl@0: }
sl@0: #endif
sl@0: 
sl@0: 
sl@0: /*
sl@0: ** Make sure the given Mem is \u0000 terminated.
sl@0: */
sl@0: int sqlite3VdbeMemNulTerminate(Mem *pMem){
sl@0:   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0:   if( (pMem->flags & MEM_Term)!=0 || (pMem->flags & MEM_Str)==0 ){
sl@0:     return SQLITE_OK;   /* Nothing to do */
sl@0:   }
sl@0:   if( sqlite3VdbeMemGrow(pMem, pMem->n+2, 1) ){
sl@0:     return SQLITE_NOMEM;
sl@0:   }
sl@0:   pMem->z[pMem->n] = 0;
sl@0:   pMem->z[pMem->n+1] = 0;
sl@0:   pMem->flags |= MEM_Term;
sl@0:   return SQLITE_OK;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Add MEM_Str to the set of representations for the given Mem.  Numbers
sl@0: ** are converted using sqlite3_snprintf().  Converting a BLOB to a string
sl@0: ** is a no-op.
sl@0: **
sl@0: ** Existing representations MEM_Int and MEM_Real are *not* invalidated.
sl@0: **
sl@0: ** A MEM_Null value will never be passed to this function. This function is
sl@0: ** used for converting values to text for returning to the user (i.e. via
sl@0: ** sqlite3_value_text()), or for ensuring that values to be used as btree
sl@0: ** keys are strings. In the former case a NULL pointer is returned the
sl@0: ** user and the later is an internal programming error.
sl@0: */
sl@0: int sqlite3VdbeMemStringify(Mem *pMem, int enc){
sl@0:   int rc = SQLITE_OK;
sl@0:   int fg = pMem->flags;
sl@0:   const int nByte = 32;
sl@0: 
sl@0:   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0:   assert( !(fg&MEM_Zero) );
sl@0:   assert( !(fg&(MEM_Str|MEM_Blob)) );
sl@0:   assert( fg&(MEM_Int|MEM_Real) );
sl@0: 
sl@0:   if( sqlite3VdbeMemGrow(pMem, nByte, 0) ){
sl@0:     return SQLITE_NOMEM;
sl@0:   }
sl@0: 
sl@0:   /* For a Real or Integer, use sqlite3_mprintf() to produce the UTF-8
sl@0:   ** string representation of the value. Then, if the required encoding
sl@0:   ** is UTF-16le or UTF-16be do a translation.
sl@0:   ** 
sl@0:   ** FIX ME: It would be better if sqlite3_snprintf() could do UTF-16.
sl@0:   */
sl@0:   if( fg & MEM_Int ){
sl@0:     sqlite3_snprintf(nByte, pMem->z, "%lld", pMem->u.i);
sl@0:   }else{
sl@0:     assert( fg & MEM_Real );
sl@0:     sqlite3_snprintf(nByte, pMem->z, "%!.15g", pMem->r);
sl@0:   }
sl@0:   pMem->n = strlen(pMem->z);
sl@0:   pMem->enc = SQLITE_UTF8;
sl@0:   pMem->flags |= MEM_Str|MEM_Term;
sl@0:   sqlite3VdbeChangeEncoding(pMem, enc);
sl@0:   return rc;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Memory cell pMem contains the context of an aggregate function.
sl@0: ** This routine calls the finalize method for that function.  The
sl@0: ** result of the aggregate is stored back into pMem.
sl@0: **
sl@0: ** Return SQLITE_ERROR if the finalizer reports an error.  SQLITE_OK
sl@0: ** otherwise.
sl@0: */
sl@0: int sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){
sl@0:   int rc = SQLITE_OK;
sl@0:   if( pFunc && pFunc->xFinalize ){
sl@0:     sqlite3_context ctx;
sl@0:     assert( (pMem->flags & MEM_Null)!=0 || pFunc==pMem->u.pDef );
sl@0:     assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0:     ctx.s.flags = MEM_Null;
sl@0:     ctx.s.db = pMem->db;
sl@0:     ctx.s.zMalloc = 0;
sl@0:     ctx.pMem = pMem;
sl@0:     ctx.pFunc = pFunc;
sl@0:     ctx.isError = 0;
sl@0:     pFunc->xFinalize(&ctx);
sl@0:     assert( 0==(pMem->flags&MEM_Dyn) && !pMem->xDel );
sl@0:     sqlite3DbFree(pMem->db, pMem->zMalloc);
sl@0:     *pMem = ctx.s;
sl@0:     rc = (ctx.isError?SQLITE_ERROR:SQLITE_OK);
sl@0:   }
sl@0:   return rc;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** If the memory cell contains a string value that must be freed by
sl@0: ** invoking an external callback, free it now. Calling this function
sl@0: ** does not free any Mem.zMalloc buffer.
sl@0: */
sl@0: void sqlite3VdbeMemReleaseExternal(Mem *p){
sl@0:   assert( p->db==0 || sqlite3_mutex_held(p->db->mutex) );
sl@0:   if( p->flags&MEM_Agg ){
sl@0:     sqlite3VdbeMemFinalize(p, p->u.pDef);
sl@0:     assert( (p->flags & MEM_Agg)==0 );
sl@0:     sqlite3VdbeMemRelease(p);
sl@0:   }else if( p->flags&MEM_Dyn && p->xDel ){
sl@0:     p->xDel((void *)p->z);
sl@0:     p->xDel = 0;
sl@0:   }
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Release any memory held by the Mem. This may leave the Mem in an
sl@0: ** inconsistent state, for example with (Mem.z==0) and
sl@0: ** (Mem.type==SQLITE_TEXT).
sl@0: */
sl@0: void sqlite3VdbeMemRelease(Mem *p){
sl@0:   sqlite3VdbeMemReleaseExternal(p);
sl@0:   sqlite3DbFree(p->db, p->zMalloc);
sl@0:   p->z = 0;
sl@0:   p->zMalloc = 0;
sl@0:   p->xDel = 0;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Convert a 64-bit IEEE double into a 64-bit signed integer.
sl@0: ** If the double is too large, return 0x8000000000000000.
sl@0: **
sl@0: ** Most systems appear to do this simply by assigning
sl@0: ** variables and without the extra range tests.  But
sl@0: ** there are reports that windows throws an expection
sl@0: ** if the floating point value is out of range. (See ticket #2880.)
sl@0: ** Because we do not completely understand the problem, we will
sl@0: ** take the conservative approach and always do range tests
sl@0: ** before attempting the conversion.
sl@0: */
sl@0: static i64 doubleToInt64(double r){
sl@0:   /*
sl@0:   ** Many compilers we encounter do not define constants for the
sl@0:   ** minimum and maximum 64-bit integers, or they define them
sl@0:   ** inconsistently.  And many do not understand the "LL" notation.
sl@0:   ** So we define our own static constants here using nothing
sl@0:   ** larger than a 32-bit integer constant.
sl@0:   */
sl@0:   static const i64 maxInt = LARGEST_INT64;
sl@0:   static const i64 minInt = SMALLEST_INT64;
sl@0: 
sl@0:   if( r<(double)minInt ){
sl@0:     return minInt;
sl@0:   }else if( r>(double)maxInt ){
sl@0:     return minInt;
sl@0:   }else{
sl@0:     return (i64)r;
sl@0:   }
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Return some kind of integer value which is the best we can do
sl@0: ** at representing the value that *pMem describes as an integer.
sl@0: ** If pMem is an integer, then the value is exact.  If pMem is
sl@0: ** a floating-point then the value returned is the integer part.
sl@0: ** If pMem is a string or blob, then we make an attempt to convert
sl@0: ** it into a integer and return that.  If pMem is NULL, return 0.
sl@0: **
sl@0: ** If pMem is a string, its encoding might be changed.
sl@0: */
sl@0: i64 sqlite3VdbeIntValue(Mem *pMem){
sl@0:   int flags;
sl@0:   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0:   flags = pMem->flags;
sl@0:   if( flags & MEM_Int ){
sl@0:     return pMem->u.i;
sl@0:   }else if( flags & MEM_Real ){
sl@0:     return doubleToInt64(pMem->r);
sl@0:   }else if( flags & (MEM_Str|MEM_Blob) ){
sl@0:     i64 value;
sl@0:     pMem->flags |= MEM_Str;
sl@0:     if( sqlite3VdbeChangeEncoding(pMem, SQLITE_UTF8)
sl@0:        || sqlite3VdbeMemNulTerminate(pMem) ){
sl@0:       return 0;
sl@0:     }
sl@0:     assert( pMem->z );
sl@0:     sqlite3Atoi64(pMem->z, &value);
sl@0:     return value;
sl@0:   }else{
sl@0:     return 0;
sl@0:   }
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Return the best representation of pMem that we can get into a
sl@0: ** double.  If pMem is already a double or an integer, return its
sl@0: ** value.  If it is a string or blob, try to convert it to a double.
sl@0: ** If it is a NULL, return 0.0.
sl@0: */
sl@0: double sqlite3VdbeRealValue(Mem *pMem){
sl@0:   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0:   if( pMem->flags & MEM_Real ){
sl@0:     return pMem->r;
sl@0:   }else if( pMem->flags & MEM_Int ){
sl@0:     return (double)pMem->u.i;
sl@0:   }else if( pMem->flags & (MEM_Str|MEM_Blob) ){
sl@0:     double val = 0.0;
sl@0:     pMem->flags |= MEM_Str;
sl@0:     if( sqlite3VdbeChangeEncoding(pMem, SQLITE_UTF8)
sl@0:        || sqlite3VdbeMemNulTerminate(pMem) ){
sl@0:       return 0.0;
sl@0:     }
sl@0:     assert( pMem->z );
sl@0:     sqlite3AtoF(pMem->z, &val);
sl@0:     return val;
sl@0:   }else{
sl@0:     return 0.0;
sl@0:   }
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** The MEM structure is already a MEM_Real.  Try to also make it a
sl@0: ** MEM_Int if we can.
sl@0: */
sl@0: void sqlite3VdbeIntegerAffinity(Mem *pMem){
sl@0:   assert( pMem->flags & MEM_Real );
sl@0:   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0: 
sl@0:   pMem->u.i = doubleToInt64(pMem->r);
sl@0:   if( pMem->r==(double)pMem->u.i ){
sl@0:     pMem->flags |= MEM_Int;
sl@0:   }
sl@0: }
sl@0: 
sl@0: static void setTypeFlag(Mem *pMem, int f){
sl@0:   MemSetTypeFlag(pMem, f);
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Convert pMem to type integer.  Invalidate any prior representations.
sl@0: */
sl@0: int sqlite3VdbeMemIntegerify(Mem *pMem){
sl@0:   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0:   pMem->u.i = sqlite3VdbeIntValue(pMem);
sl@0:   setTypeFlag(pMem, MEM_Int);
sl@0:   return SQLITE_OK;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Convert pMem so that it is of type MEM_Real.
sl@0: ** Invalidate any prior representations.
sl@0: */
sl@0: int sqlite3VdbeMemRealify(Mem *pMem){
sl@0:   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0:   pMem->r = sqlite3VdbeRealValue(pMem);
sl@0:   setTypeFlag(pMem, MEM_Real);
sl@0:   return SQLITE_OK;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Convert pMem so that it has types MEM_Real or MEM_Int or both.
sl@0: ** Invalidate any prior representations.
sl@0: */
sl@0: int sqlite3VdbeMemNumerify(Mem *pMem){
sl@0:   double r1, r2;
sl@0:   i64 i;
sl@0:   assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_Null))==0 );
sl@0:   assert( (pMem->flags & (MEM_Blob|MEM_Str))!=0 );
sl@0:   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0:   r1 = sqlite3VdbeRealValue(pMem);
sl@0:   i = doubleToInt64(r1);
sl@0:   r2 = (double)i;
sl@0:   if( r1==r2 ){
sl@0:     sqlite3VdbeMemIntegerify(pMem);
sl@0:   }else{
sl@0:     pMem->r = r1;
sl@0:     setTypeFlag(pMem, MEM_Real);
sl@0:   }
sl@0:   return SQLITE_OK;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Delete any previous value and set the value stored in *pMem to NULL.
sl@0: */
sl@0: void sqlite3VdbeMemSetNull(Mem *pMem){
sl@0:   setTypeFlag(pMem, MEM_Null);
sl@0:   pMem->type = SQLITE_NULL;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Delete any previous value and set the value to be a BLOB of length
sl@0: ** n containing all zeros.
sl@0: */
sl@0: void sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
sl@0:   sqlite3VdbeMemRelease(pMem);
sl@0:   setTypeFlag(pMem, MEM_Blob);
sl@0:   pMem->flags = MEM_Blob|MEM_Zero;
sl@0:   pMem->type = SQLITE_BLOB;
sl@0:   pMem->n = 0;
sl@0:   if( n<0 ) n = 0;
sl@0:   pMem->u.i = n;
sl@0:   pMem->enc = SQLITE_UTF8;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Delete any previous value and set the value stored in *pMem to val,
sl@0: ** manifest type INTEGER.
sl@0: */
sl@0: void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
sl@0:   sqlite3VdbeMemRelease(pMem);
sl@0:   pMem->u.i = val;
sl@0:   pMem->flags = MEM_Int;
sl@0:   pMem->type = SQLITE_INTEGER;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Delete any previous value and set the value stored in *pMem to val,
sl@0: ** manifest type REAL.
sl@0: */
sl@0: void sqlite3VdbeMemSetDouble(Mem *pMem, double val){
sl@0:   if( sqlite3IsNaN(val) ){
sl@0:     sqlite3VdbeMemSetNull(pMem);
sl@0:   }else{
sl@0:     sqlite3VdbeMemRelease(pMem);
sl@0:     pMem->r = val;
sl@0:     pMem->flags = MEM_Real;
sl@0:     pMem->type = SQLITE_FLOAT;
sl@0:   }
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Return true if the Mem object contains a TEXT or BLOB that is
sl@0: ** too large - whose size exceeds SQLITE_MAX_LENGTH.
sl@0: */
sl@0: int sqlite3VdbeMemTooBig(Mem *p){
sl@0:   assert( p->db!=0 );
sl@0:   if( p->flags & (MEM_Str|MEM_Blob) ){
sl@0:     int n = p->n;
sl@0:     if( p->flags & MEM_Zero ){
sl@0:       n += p->u.i;
sl@0:     }
sl@0:     return n>p->db->aLimit[SQLITE_LIMIT_LENGTH];
sl@0:   }
sl@0:   return 0; 
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Size of struct Mem not including the Mem.zMalloc member.
sl@0: */
sl@0: #define MEMCELLSIZE (size_t)(&(((Mem *)0)->zMalloc))
sl@0: 
sl@0: /*
sl@0: ** Make an shallow copy of pFrom into pTo.  Prior contents of
sl@0: ** pTo are freed.  The pFrom->z field is not duplicated.  If
sl@0: ** pFrom->z is used, then pTo->z points to the same thing as pFrom->z
sl@0: ** and flags gets srcType (either MEM_Ephem or MEM_Static).
sl@0: */
sl@0: void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
sl@0:   sqlite3VdbeMemReleaseExternal(pTo);
sl@0:   memcpy(pTo, pFrom, MEMCELLSIZE);
sl@0:   pTo->xDel = 0;
sl@0:   if( (pFrom->flags&MEM_Dyn)!=0 || pFrom->z==pFrom->zMalloc ){
sl@0:     pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
sl@0:     assert( srcType==MEM_Ephem || srcType==MEM_Static );
sl@0:     pTo->flags |= srcType;
sl@0:   }
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Make a full copy of pFrom into pTo.  Prior contents of pTo are
sl@0: ** freed before the copy is made.
sl@0: */
sl@0: int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
sl@0:   int rc = SQLITE_OK;
sl@0: 
sl@0:   sqlite3VdbeMemReleaseExternal(pTo);
sl@0:   memcpy(pTo, pFrom, MEMCELLSIZE);
sl@0:   pTo->flags &= ~MEM_Dyn;
sl@0: 
sl@0:   if( pTo->flags&(MEM_Str|MEM_Blob) ){
sl@0:     if( 0==(pFrom->flags&MEM_Static) ){
sl@0:       pTo->flags |= MEM_Ephem;
sl@0:       rc = sqlite3VdbeMemMakeWriteable(pTo);
sl@0:     }
sl@0:   }
sl@0: 
sl@0:   return rc;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Transfer the contents of pFrom to pTo. Any existing value in pTo is
sl@0: ** freed. If pFrom contains ephemeral data, a copy is made.
sl@0: **
sl@0: ** pFrom contains an SQL NULL when this routine returns.
sl@0: */
sl@0: void sqlite3VdbeMemMove(Mem *pTo, Mem *pFrom){
sl@0:   assert( pFrom->db==0 || sqlite3_mutex_held(pFrom->db->mutex) );
sl@0:   assert( pTo->db==0 || sqlite3_mutex_held(pTo->db->mutex) );
sl@0:   assert( pFrom->db==0 || pTo->db==0 || pFrom->db==pTo->db );
sl@0: 
sl@0:   sqlite3VdbeMemRelease(pTo);
sl@0:   memcpy(pTo, pFrom, sizeof(Mem));
sl@0:   pFrom->flags = MEM_Null;
sl@0:   pFrom->xDel = 0;
sl@0:   pFrom->zMalloc = 0;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Change the value of a Mem to be a string or a BLOB.
sl@0: **
sl@0: ** The memory management strategy depends on the value of the xDel
sl@0: ** parameter. If the value passed is SQLITE_TRANSIENT, then the 
sl@0: ** string is copied into a (possibly existing) buffer managed by the 
sl@0: ** Mem structure. Otherwise, any existing buffer is freed and the
sl@0: ** pointer copied.
sl@0: */
sl@0: int sqlite3VdbeMemSetStr(
sl@0:   Mem *pMem,          /* Memory cell to set to string value */
sl@0:   const char *z,      /* String pointer */
sl@0:   int n,              /* Bytes in string, or negative */
sl@0:   u8 enc,             /* Encoding of z.  0 for BLOBs */
sl@0:   void (*xDel)(void*) /* Destructor function */
sl@0: ){
sl@0:   int nByte = n;      /* New value for pMem->n */
sl@0:   int iLimit;         /* Maximum allowed string or blob size */
sl@0:   int flags = 0;      /* New value for pMem->flags */
sl@0: 
sl@0:   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
sl@0: 
sl@0:   /* If z is a NULL pointer, set pMem to contain an SQL NULL. */
sl@0:   if( !z ){
sl@0:     sqlite3VdbeMemSetNull(pMem);
sl@0:     return SQLITE_OK;
sl@0:   }
sl@0: 
sl@0:   if( pMem->db ){
sl@0:     iLimit = pMem->db->aLimit[SQLITE_LIMIT_LENGTH];
sl@0:   }else{
sl@0:     iLimit = SQLITE_MAX_LENGTH;
sl@0:   }
sl@0:   flags = (enc==0?MEM_Blob:MEM_Str);
sl@0:   if( nByte<0 ){
sl@0:     assert( enc!=0 );
sl@0:     if( enc==SQLITE_UTF8 ){
sl@0:       for(nByte=0; nByte<=iLimit && z[nByte]; nByte++){}
sl@0:     }else{
sl@0:       for(nByte=0; nByte<=iLimit && (z[nByte] | z[nByte+1]); nByte+=2){}
sl@0:     }
sl@0:     flags |= MEM_Term;
sl@0:   }
sl@0:   if( nByte>iLimit ){
sl@0:     return SQLITE_TOOBIG;
sl@0:   }
sl@0: 
sl@0:   /* The following block sets the new values of Mem.z and Mem.xDel. It
sl@0:   ** also sets a flag in local variable "flags" to indicate the memory
sl@0:   ** management (one of MEM_Dyn or MEM_Static).
sl@0:   */
sl@0:   if( xDel==SQLITE_TRANSIENT ){
sl@0:     int nAlloc = nByte;
sl@0:     if( flags&MEM_Term ){
sl@0:       nAlloc += (enc==SQLITE_UTF8?1:2);
sl@0:     }
sl@0:     if( sqlite3VdbeMemGrow(pMem, nAlloc, 0) ){
sl@0:       return SQLITE_NOMEM;
sl@0:     }
sl@0:     memcpy(pMem->z, z, nAlloc);
sl@0:   }else if( xDel==SQLITE_DYNAMIC ){
sl@0:     sqlite3VdbeMemRelease(pMem);
sl@0:     pMem->zMalloc = pMem->z = (char *)z;
sl@0:     pMem->xDel = 0;
sl@0:   }else{
sl@0:     sqlite3VdbeMemRelease(pMem);
sl@0:     pMem->z = (char *)z;
sl@0:     pMem->xDel = xDel;
sl@0:     flags |= ((xDel==SQLITE_STATIC)?MEM_Static:MEM_Dyn);
sl@0:   }
sl@0: 
sl@0:   pMem->n = nByte;
sl@0:   pMem->flags = flags;
sl@0:   pMem->enc = (enc==0 ? SQLITE_UTF8 : enc);
sl@0:   pMem->type = (enc==0 ? SQLITE_BLOB : SQLITE_TEXT);
sl@0: 
sl@0: #ifndef SQLITE_OMIT_UTF16
sl@0:   if( pMem->enc!=SQLITE_UTF8 && sqlite3VdbeMemHandleBom(pMem) ){
sl@0:     return SQLITE_NOMEM;
sl@0:   }
sl@0: #endif
sl@0: 
sl@0:   return SQLITE_OK;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Compare the values contained by the two memory cells, returning
sl@0: ** negative, zero or positive if pMem1 is less than, equal to, or greater
sl@0: ** than pMem2. Sorting order is NULL's first, followed by numbers (integers
sl@0: ** and reals) sorted numerically, followed by text ordered by the collating
sl@0: ** sequence pColl and finally blob's ordered by memcmp().
sl@0: **
sl@0: ** Two NULL values are considered equal by this function.
sl@0: */
sl@0: int sqlite3MemCompare(const Mem *pMem1, const Mem *pMem2, const CollSeq *pColl){
sl@0:   int rc;
sl@0:   int f1, f2;
sl@0:   int combined_flags;
sl@0: 
sl@0:   /* Interchange pMem1 and pMem2 if the collating sequence specifies
sl@0:   ** DESC order.
sl@0:   */
sl@0:   f1 = pMem1->flags;
sl@0:   f2 = pMem2->flags;
sl@0:   combined_flags = f1|f2;
sl@0:  
sl@0:   /* If one value is NULL, it is less than the other. If both values
sl@0:   ** are NULL, return 0.
sl@0:   */
sl@0:   if( combined_flags&MEM_Null ){
sl@0:     return (f2&MEM_Null) - (f1&MEM_Null);
sl@0:   }
sl@0: 
sl@0:   /* If one value is a number and the other is not, the number is less.
sl@0:   ** If both are numbers, compare as reals if one is a real, or as integers
sl@0:   ** if both values are integers.
sl@0:   */
sl@0:   if( combined_flags&(MEM_Int|MEM_Real) ){
sl@0:     if( !(f1&(MEM_Int|MEM_Real)) ){
sl@0:       return 1;
sl@0:     }
sl@0:     if( !(f2&(MEM_Int|MEM_Real)) ){
sl@0:       return -1;
sl@0:     }
sl@0:     if( (f1 & f2 & MEM_Int)==0 ){
sl@0:       double r1, r2;
sl@0:       if( (f1&MEM_Real)==0 ){
sl@0:         r1 = pMem1->u.i;
sl@0:       }else{
sl@0:         r1 = pMem1->r;
sl@0:       }
sl@0:       if( (f2&MEM_Real)==0 ){
sl@0:         r2 = pMem2->u.i;
sl@0:       }else{
sl@0:         r2 = pMem2->r;
sl@0:       }
sl@0:       if( r1<r2 ) return -1;
sl@0:       if( r1>r2 ) return 1;
sl@0:       return 0;
sl@0:     }else{
sl@0:       assert( f1&MEM_Int );
sl@0:       assert( f2&MEM_Int );
sl@0:       if( pMem1->u.i < pMem2->u.i ) return -1;
sl@0:       if( pMem1->u.i > pMem2->u.i ) return 1;
sl@0:       return 0;
sl@0:     }
sl@0:   }
sl@0: 
sl@0:   /* If one value is a string and the other is a blob, the string is less.
sl@0:   ** If both are strings, compare using the collating functions.
sl@0:   */
sl@0:   if( combined_flags&MEM_Str ){
sl@0:     if( (f1 & MEM_Str)==0 ){
sl@0:       return 1;
sl@0:     }
sl@0:     if( (f2 & MEM_Str)==0 ){
sl@0:       return -1;
sl@0:     }
sl@0: 
sl@0:     assert( pMem1->enc==pMem2->enc );
sl@0:     assert( pMem1->enc==SQLITE_UTF8 || 
sl@0:             pMem1->enc==SQLITE_UTF16LE || pMem1->enc==SQLITE_UTF16BE );
sl@0: 
sl@0:     /* The collation sequence must be defined at this point, even if
sl@0:     ** the user deletes the collation sequence after the vdbe program is
sl@0:     ** compiled (this was not always the case).
sl@0:     */
sl@0:     assert( !pColl || pColl->xCmp );
sl@0: 
sl@0:     if( pColl ){
sl@0:       if( pMem1->enc==pColl->enc ){
sl@0:         /* The strings are already in the correct encoding.  Call the
sl@0:         ** comparison function directly */
sl@0:         return pColl->xCmp(pColl->pUser,pMem1->n,pMem1->z,pMem2->n,pMem2->z);
sl@0:       }else{
sl@0:         u8 origEnc = pMem1->enc;
sl@0:         const void *v1, *v2;
sl@0:         int n1, n2;
sl@0:         /* Convert the strings into the encoding that the comparison
sl@0:         ** function expects */
sl@0:         v1 = sqlite3ValueText((sqlite3_value*)pMem1, pColl->enc);
sl@0:         n1 = v1==0 ? 0 : pMem1->n;
sl@0:         assert( n1==sqlite3ValueBytes((sqlite3_value*)pMem1, pColl->enc) );
sl@0:         v2 = sqlite3ValueText((sqlite3_value*)pMem2, pColl->enc);
sl@0:         n2 = v2==0 ? 0 : pMem2->n;
sl@0:         assert( n2==sqlite3ValueBytes((sqlite3_value*)pMem2, pColl->enc) );
sl@0:         /* Do the comparison */
sl@0:         rc = pColl->xCmp(pColl->pUser, n1, v1, n2, v2);
sl@0:         /* Convert the strings back into the database encoding */
sl@0:         sqlite3ValueText((sqlite3_value*)pMem1, origEnc);
sl@0:         sqlite3ValueText((sqlite3_value*)pMem2, origEnc);
sl@0:         return rc;
sl@0:       }
sl@0:     }
sl@0:     /* If a NULL pointer was passed as the collate function, fall through
sl@0:     ** to the blob case and use memcmp().  */
sl@0:   }
sl@0:  
sl@0:   /* Both values must be blobs.  Compare using memcmp().  */
sl@0:   rc = memcmp(pMem1->z, pMem2->z, (pMem1->n>pMem2->n)?pMem2->n:pMem1->n);
sl@0:   if( rc==0 ){
sl@0:     rc = pMem1->n - pMem2->n;
sl@0:   }
sl@0:   return rc;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Move data out of a btree key or data field and into a Mem structure.
sl@0: ** The data or key is taken from the entry that pCur is currently pointing
sl@0: ** to.  offset and amt determine what portion of the data or key to retrieve.
sl@0: ** key is true to get the key or false to get data.  The result is written
sl@0: ** into the pMem element.
sl@0: **
sl@0: ** The pMem structure is assumed to be uninitialized.  Any prior content
sl@0: ** is overwritten without being freed.
sl@0: **
sl@0: ** If this routine fails for any reason (malloc returns NULL or unable
sl@0: ** to read from the disk) then the pMem is left in an inconsistent state.
sl@0: */
sl@0: int sqlite3VdbeMemFromBtree(
sl@0:   BtCursor *pCur,   /* Cursor pointing at record to retrieve. */
sl@0:   int offset,       /* Offset from the start of data to return bytes from. */
sl@0:   int amt,          /* Number of bytes to return. */
sl@0:   int key,          /* If true, retrieve from the btree key, not data. */
sl@0:   Mem *pMem         /* OUT: Return data in this Mem structure. */
sl@0: ){
sl@0:   char *zData;       /* Data from the btree layer */
sl@0:   int available = 0; /* Number of bytes available on the local btree page */
sl@0:   sqlite3 *db;       /* Database connection */
sl@0:   int rc = SQLITE_OK;
sl@0: 
sl@0:   db = sqlite3BtreeCursorDb(pCur);
sl@0:   assert( sqlite3_mutex_held(db->mutex) );
sl@0:   if( key ){
sl@0:     zData = (char *)sqlite3BtreeKeyFetch(pCur, &available);
sl@0:   }else{
sl@0:     zData = (char *)sqlite3BtreeDataFetch(pCur, &available);
sl@0:   }
sl@0:   assert( zData!=0 );
sl@0: 
sl@0:   if( offset+amt<=available && ((pMem->flags&MEM_Dyn)==0 || pMem->xDel) ){
sl@0:     sqlite3VdbeMemRelease(pMem);
sl@0:     pMem->z = &zData[offset];
sl@0:     pMem->flags = MEM_Blob|MEM_Ephem;
sl@0:   }else if( SQLITE_OK==(rc = sqlite3VdbeMemGrow(pMem, amt+2, 0)) ){
sl@0:     pMem->flags = MEM_Blob|MEM_Dyn|MEM_Term;
sl@0:     pMem->enc = 0;
sl@0:     pMem->type = SQLITE_BLOB;
sl@0:     if( key ){
sl@0:       rc = sqlite3BtreeKey(pCur, offset, amt, pMem->z);
sl@0:     }else{
sl@0:       rc = sqlite3BtreeData(pCur, offset, amt, pMem->z);
sl@0:     }
sl@0:     pMem->z[amt] = 0;
sl@0:     pMem->z[amt+1] = 0;
sl@0:     if( rc!=SQLITE_OK ){
sl@0:       sqlite3VdbeMemRelease(pMem);
sl@0:     }
sl@0:   }
sl@0:   pMem->n = amt;
sl@0: 
sl@0:   return rc;
sl@0: }
sl@0: 
sl@0: #if 0
sl@0: /*
sl@0: ** Perform various checks on the memory cell pMem. An assert() will
sl@0: ** fail if pMem is internally inconsistent.
sl@0: */
sl@0: void sqlite3VdbeMemSanity(Mem *pMem){
sl@0:   int flags = pMem->flags;
sl@0:   assert( flags!=0 );  /* Must define some type */
sl@0:   if( flags & (MEM_Str|MEM_Blob) ){
sl@0:     int x = flags & (MEM_Static|MEM_Dyn|MEM_Ephem|MEM_Short);
sl@0:     assert( x!=0 );            /* Strings must define a string subtype */
sl@0:     assert( (x & (x-1))==0 );  /* Only one string subtype can be defined */
sl@0:     assert( pMem->z!=0 );      /* Strings must have a value */
sl@0:     /* Mem.z points to Mem.zShort iff the subtype is MEM_Short */
sl@0:     assert( (x & MEM_Short)==0 || pMem->z==pMem->zShort );
sl@0:     assert( (x & MEM_Short)!=0 || pMem->z!=pMem->zShort );
sl@0:     /* No destructor unless there is MEM_Dyn */
sl@0:     assert( pMem->xDel==0 || (pMem->flags & MEM_Dyn)!=0 );
sl@0: 
sl@0:     if( (flags & MEM_Str) ){
sl@0:       assert( pMem->enc==SQLITE_UTF8 || 
sl@0:               pMem->enc==SQLITE_UTF16BE ||
sl@0:               pMem->enc==SQLITE_UTF16LE 
sl@0:       );
sl@0:       /* If the string is UTF-8 encoded and nul terminated, then pMem->n
sl@0:       ** must be the length of the string.  (Later:)  If the database file
sl@0:       ** has been corrupted, '\000' characters might have been inserted
sl@0:       ** into the middle of the string.  In that case, the strlen() might
sl@0:       ** be less.
sl@0:       */
sl@0:       if( pMem->enc==SQLITE_UTF8 && (flags & MEM_Term) ){ 
sl@0:         assert( strlen(pMem->z)<=pMem->n );
sl@0:         assert( pMem->z[pMem->n]==0 );
sl@0:       }
sl@0:     }
sl@0:   }else{
sl@0:     /* Cannot define a string subtype for non-string objects */
sl@0:     assert( (pMem->flags & (MEM_Static|MEM_Dyn|MEM_Ephem|MEM_Short))==0 );
sl@0:     assert( pMem->xDel==0 );
sl@0:   }
sl@0:   /* MEM_Null excludes all other types */
sl@0:   assert( (pMem->flags&(MEM_Str|MEM_Int|MEM_Real|MEM_Blob))==0
sl@0:           || (pMem->flags&MEM_Null)==0 );
sl@0:   /* If the MEM is both real and integer, the values are equal */
sl@0:   assert( (pMem->flags & (MEM_Int|MEM_Real))!=(MEM_Int|MEM_Real) 
sl@0:           || pMem->r==pMem->u.i );
sl@0: }
sl@0: #endif
sl@0: 
sl@0: /* This function is only available internally, it is not part of the
sl@0: ** external API. It works in a similar way to sqlite3_value_text(),
sl@0: ** except the data returned is in the encoding specified by the second
sl@0: ** parameter, which must be one of SQLITE_UTF16BE, SQLITE_UTF16LE or
sl@0: ** SQLITE_UTF8.
sl@0: **
sl@0: ** (2006-02-16:)  The enc value can be or-ed with SQLITE_UTF16_ALIGNED.
sl@0: ** If that is the case, then the result must be aligned on an even byte
sl@0: ** boundary.
sl@0: */
sl@0: const void *sqlite3ValueText(sqlite3_value* pVal, u8 enc){
sl@0:   if( !pVal ) return 0;
sl@0: 
sl@0:   assert( pVal->db==0 || sqlite3_mutex_held(pVal->db->mutex) );
sl@0:   assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );
sl@0: 
sl@0:   if( pVal->flags&MEM_Null ){
sl@0:     return 0;
sl@0:   }
sl@0:   assert( (MEM_Blob>>3) == MEM_Str );
sl@0:   pVal->flags |= (pVal->flags & MEM_Blob)>>3;
sl@0:   expandBlob(pVal);
sl@0:   if( pVal->flags&MEM_Str ){
sl@0:     sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
sl@0:     if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&SQLITE_PTR_TO_INT(pVal->z)) ){
sl@0:       assert( (pVal->flags & (MEM_Ephem|MEM_Static))!=0 );
sl@0:       if( sqlite3VdbeMemMakeWriteable(pVal)!=SQLITE_OK ){
sl@0:         return 0;
sl@0:       }
sl@0:     }
sl@0:     sqlite3VdbeMemNulTerminate(pVal);
sl@0:   }else{
sl@0:     assert( (pVal->flags&MEM_Blob)==0 );
sl@0:     sqlite3VdbeMemStringify(pVal, enc);
sl@0:     assert( 0==(1&(int)pVal->z) );
sl@0:   }
sl@0:   assert(pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) || pVal->db==0
sl@0:               || pVal->db->mallocFailed );
sl@0:   if( pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) ){
sl@0:     return pVal->z;
sl@0:   }else{
sl@0:     return 0;
sl@0:   }
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Create a new sqlite3_value object.
sl@0: */
sl@0: sqlite3_value *sqlite3ValueNew(sqlite3 *db){
sl@0:   Mem *p = sqlite3DbMallocZero(db, sizeof(*p));
sl@0:   if( p ){
sl@0:     p->flags = MEM_Null;
sl@0:     p->type = SQLITE_NULL;
sl@0:     p->db = db;
sl@0:   }
sl@0:   return p;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Create a new sqlite3_value object, containing the value of pExpr.
sl@0: **
sl@0: ** This only works for very simple expressions that consist of one constant
sl@0: ** token (i.e. "5", "5.1", "'a string'"). If the expression can
sl@0: ** be converted directly into a value, then the value is allocated and
sl@0: ** a pointer written to *ppVal. The caller is responsible for deallocating
sl@0: ** the value by passing it to sqlite3ValueFree() later on. If the expression
sl@0: ** cannot be converted to a value, then *ppVal is set to NULL.
sl@0: */
sl@0: int sqlite3ValueFromExpr(
sl@0:   sqlite3 *db,              /* The database connection */
sl@0:   Expr *pExpr,              /* The expression to evaluate */
sl@0:   u8 enc,                   /* Encoding to use */
sl@0:   u8 affinity,              /* Affinity to use */
sl@0:   sqlite3_value **ppVal     /* Write the new value here */
sl@0: ){
sl@0:   int op;
sl@0:   char *zVal = 0;
sl@0:   sqlite3_value *pVal = 0;
sl@0: 
sl@0:   if( !pExpr ){
sl@0:     *ppVal = 0;
sl@0:     return SQLITE_OK;
sl@0:   }
sl@0:   op = pExpr->op;
sl@0: 
sl@0:   if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
sl@0:     zVal = sqlite3DbStrNDup(db, (char*)pExpr->token.z, pExpr->token.n);
sl@0:     pVal = sqlite3ValueNew(db);
sl@0:     if( !zVal || !pVal ) goto no_mem;
sl@0:     sqlite3Dequote(zVal);
sl@0:     sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
sl@0:     if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_NONE ){
sl@0:       sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, enc);
sl@0:     }else{
sl@0:       sqlite3ValueApplyAffinity(pVal, affinity, enc);
sl@0:     }
sl@0:   }else if( op==TK_UMINUS ) {
sl@0:     if( SQLITE_OK==sqlite3ValueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal) ){
sl@0:       pVal->u.i = -1 * pVal->u.i;
sl@0:       pVal->r = -1.0 * pVal->r;
sl@0:     }
sl@0:   }
sl@0: #ifndef SQLITE_OMIT_BLOB_LITERAL
sl@0:   else if( op==TK_BLOB ){
sl@0:     int nVal;
sl@0:     assert( pExpr->token.n>=3 );
sl@0:     assert( pExpr->token.z[0]=='x' || pExpr->token.z[0]=='X' );
sl@0:     assert( pExpr->token.z[1]=='\'' );
sl@0:     assert( pExpr->token.z[pExpr->token.n-1]=='\'' );
sl@0:     pVal = sqlite3ValueNew(db);
sl@0:     nVal = pExpr->token.n - 3;
sl@0:     zVal = (char*)pExpr->token.z + 2;
sl@0:     sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
sl@0:                          0, SQLITE_DYNAMIC);
sl@0:   }
sl@0: #endif
sl@0: 
sl@0:   *ppVal = pVal;
sl@0:   return SQLITE_OK;
sl@0: 
sl@0: no_mem:
sl@0:   db->mallocFailed = 1;
sl@0:   sqlite3DbFree(db, zVal);
sl@0:   sqlite3ValueFree(pVal);
sl@0:   *ppVal = 0;
sl@0:   return SQLITE_NOMEM;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Change the string value of an sqlite3_value object
sl@0: */
sl@0: void sqlite3ValueSetStr(
sl@0:   sqlite3_value *v,     /* Value to be set */
sl@0:   int n,                /* Length of string z */
sl@0:   const void *z,        /* Text of the new string */
sl@0:   u8 enc,               /* Encoding to use */
sl@0:   void (*xDel)(void*)   /* Destructor for the string */
sl@0: ){
sl@0:   if( v ) sqlite3VdbeMemSetStr((Mem *)v, z, n, enc, xDel);
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Free an sqlite3_value object
sl@0: */
sl@0: void sqlite3ValueFree(sqlite3_value *v){
sl@0:   if( !v ) return;
sl@0:   sqlite3VdbeMemRelease((Mem *)v);
sl@0:   sqlite3DbFree(((Mem*)v)->db, v);
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Return the number of bytes in the sqlite3_value object assuming
sl@0: ** that it uses the encoding "enc"
sl@0: */
sl@0: int sqlite3ValueBytes(sqlite3_value *pVal, u8 enc){
sl@0:   Mem *p = (Mem*)pVal;
sl@0:   if( (p->flags & MEM_Blob)!=0 || sqlite3ValueText(pVal, enc) ){
sl@0:     if( p->flags & MEM_Zero ){
sl@0:       return p->n+p->u.i;
sl@0:     }else{
sl@0:       return p->n;
sl@0:     }
sl@0:   }
sl@0:   return 0;
sl@0: }