src/vdbemem.c

   1 /*
   2 ** 2004 May 26
   3 **
   4 ** The author disclaims copyright to this source code.  In place of
   5 ** a legal notice, here is a blessing:
   6 **
   7 **    May you do good and not evil.
   8 **    May you find forgiveness for yourself and forgive others.
   9 **    May you share freely, never taking more than you give.
  10 **
  11 *************************************************************************
  12 **
  13 ** This file contains code use to manipulate "Mem" structure.  A "Mem"
  14 ** stores a single value in the VDBE.  Mem is an opaque structure visible
  15 ** only within the VDBE.  Interface routines refer to a Mem using the
  16 ** name sqlite_value
  17 */
  18 #include "sqliteInt.h"
  19 #include "vdbeInt.h"
  20
  21 /* True if X is a power of two.  0 is considered a power of two here.
  22 ** In other words, return true if X has at most one bit set.
  23 */
  24 #define ISPOWEROF2(X)  (((X)&((X)-1))==0)
  25
  26 #ifdef SQLITE_DEBUG
  27 /*
  28 ** Check invariants on a Mem object.
  29 **
  30 ** This routine is intended for use inside of assert() statements, like
  31 ** this:    assert( sqlite3VdbeCheckMemInvariants(pMem) );
  32 */
  33 int sqlite3VdbeCheckMemInvariants(Mem *p){
  34   /* If MEM_Dyn is set then Mem.xDel!=0.
  35   ** Mem.xDel might not be initialized if MEM_Dyn is clear.
  36   */
  37   assert( (p->flags & MEM_Dyn)==0 || p->xDel!=0 );
  38
  39   /* MEM_Dyn may only be set if Mem.szMalloc==0.  In this way we
  40   ** ensure that if Mem.szMalloc>0 then it is safe to do
  41   ** Mem.z = Mem.zMalloc without having to check Mem.flags&MEM_Dyn.
  42   ** That saves a few cycles in inner loops. */
  43   assert( (p->flags & MEM_Dyn)==0 || p->szMalloc==0 );
  44
  45   /* Cannot have more than one of MEM_Int, MEM_Real, or MEM_IntReal */
  46   assert( ISPOWEROF2(p->flags & (MEM_Int|MEM_Real|MEM_IntReal)) );
  47
  48   if( p->flags & MEM_Null ){
  49     /* Cannot be both MEM_Null and some other type */
  50     assert( (p->flags & (MEM_Int|MEM_Real|MEM_Str|MEM_Blob|MEM_Agg))==0 );
  51
  52     /* If MEM_Null is set, then either the value is a pure NULL (the usual
  53     ** case) or it is a pointer set using sqlite3_bind_pointer() or
  54     ** sqlite3_result_pointer().  If a pointer, then MEM_Term must also be
  55     ** set.
  56     */
  57     if( (p->flags & (MEM_Term|MEM_Subtype))==(MEM_Term|MEM_Subtype) ){
  58       /* This is a pointer type.  There may be a flag to indicate what to
  59       ** do with the pointer. */
  60       assert( ((p->flags&MEM_Dyn)!=0 ? 1 : 0) +
  61               ((p->flags&MEM_Ephem)!=0 ? 1 : 0) +
  62               ((p->flags&MEM_Static)!=0 ? 1 : 0) <= 1 );
  63
  64       /* No other bits set */
  65       assert( (p->flags & ~(MEM_Null|MEM_Term|MEM_Subtype|MEM_FromBind
  66                            |MEM_Dyn|MEM_Ephem|MEM_Static))==0 );
  67     }else{
  68       /* A pure NULL might have other flags, such as MEM_Static, MEM_Dyn,
  69       ** MEM_Ephem, MEM_Cleared, or MEM_Subtype */
  70     }
  71   }else{
  72     /* The MEM_Cleared bit is only allowed on NULLs */
  73     assert( (p->flags & MEM_Cleared)==0 );
  74   }
  75
  76   /* The szMalloc field holds the correct memory allocation size */
  77   assert( p->szMalloc==0
  78        || (p->flags==MEM_Undefined
  79            && p->szMalloc<=sqlite3DbMallocSize(p->db,p->zMalloc))
  80        || p->szMalloc==sqlite3DbMallocSize(p->db,p->zMalloc));
  81
  82   /* If p holds a string or blob, the Mem.z must point to exactly
  83   ** one of the following:
  84   **
  85   **   (1) Memory in Mem.zMalloc and managed by the Mem object
  86   **   (2) Memory to be freed using Mem.xDel
  87   **   (3) An ephemeral string or blob
  88   **   (4) A static string or blob
  89   */
  90   if( (p->flags & (MEM_Str|MEM_Blob)) && p->n>0 ){
  91     assert(
  92       ((p->szMalloc>0 && p->z==p->zMalloc)? 1 : 0) +
  93       ((p->flags&MEM_Dyn)!=0 ? 1 : 0) +
  94       ((p->flags&MEM_Ephem)!=0 ? 1 : 0) +
  95       ((p->flags&MEM_Static)!=0 ? 1 : 0) == 1
  96     );
  97   }
  98   return 1;
  99 }
 100 #endif
 101
 102 /*
 103 ** Render a Mem object which is one of MEM_Int, MEM_Real, or MEM_IntReal
 104 ** into a buffer.
 105 */
 106 static void vdbeMemRenderNum(int sz, char *zBuf, Mem *p){
 107   StrAccum acc;
 108   assert( p->flags & (MEM_Int|MEM_Real|MEM_IntReal) );
 109   assert( sz>22 );
 110   if( p->flags & MEM_Int ){
 111 #if GCC_VERSION>=7000000
 112     /* Work-around for GCC bug
 113     ** https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96270 */
 114     i64 x;
 115     assert( (p->flags&MEM_Int)*2==sizeof(x) );
 116     memcpy(&x, (char*)&p->u, (p->flags&MEM_Int)*2);
 117     p->n = sqlite3Int64ToText(x, zBuf);
 118 #else
 119     p->n = sqlite3Int64ToText(p->u.i, zBuf);
 120 #endif
 121   }else{
 122     sqlite3StrAccumInit(&acc, 0, zBuf, sz, 0);
 123     sqlite3_str_appendf(&acc, "%!.15g",
 124          (p->flags & MEM_IntReal)!=0 ? (double)p->u.i : p->u.r);
 125     assert( acc.zText==zBuf && acc.mxAlloc<=0 );
 126     zBuf[acc.nChar] = 0; /* Fast version of sqlite3StrAccumFinish(&acc) */
 127     p->n = acc.nChar;
 128   }
 129 }
 130
 131 #ifdef SQLITE_DEBUG
 132 /*
 133 ** Validity checks on pMem.  pMem holds a string.
 134 **
 135 ** (1) Check that string value of pMem agrees with its integer or real value.
 136 ** (2) Check that the string is correctly zero terminated
 137 **
 138 ** A single int or real value always converts to the same strings.  But
 139 ** many different strings can be converted into the same int or real.
 140 ** If a table contains a numeric value and an index is based on the
 141 ** corresponding string value, then it is important that the string be
 142 ** derived from the numeric value, not the other way around, to ensure
 143 ** that the index and table are consistent.  See ticket
 144 ** https://www.sqlite.org/src/info/343634942dd54ab (2018-01-31) for
 145 ** an example.
 146 **
 147 ** This routine looks at pMem to verify that if it has both a numeric
 148 ** representation and a string representation then the string rep has
 149 ** been derived from the numeric and not the other way around.  It returns
 150 ** true if everything is ok and false if there is a problem.
 151 **
 152 ** This routine is for use inside of assert() statements only.
 153 */
 154 int sqlite3VdbeMemValidStrRep(Mem *p){
 155   Mem tmp;
 156   char zBuf[100];
 157   char *z;
 158   int i, j, incr;
 159   if( (p->flags & MEM_Str)==0 ) return 1;
 160   if( p->db && p->db->mallocFailed ) return 1;
 161   if( p->flags & MEM_Term ){
 162     /* Insure that the string is properly zero-terminated.  Pay particular
 163     ** attention to the case where p->n is odd */
 164     if( p->szMalloc>0 && p->z==p->zMalloc ){
 165       assert( p->enc==SQLITE_UTF8 || p->szMalloc >= ((p->n+1)&~1)+2 );
 166       assert( p->enc!=SQLITE_UTF8 || p->szMalloc >= p->n+1 );
 167     }
 168     assert( p->z[p->n]==0 );
 169     assert( p->enc==SQLITE_UTF8 || p->z[(p->n+1)&~1]==0 );
 170     assert( p->enc==SQLITE_UTF8 || p->z[((p->n+1)&~1)+1]==0 );
 171   }
 172   if( (p->flags & (MEM_Int|MEM_Real|MEM_IntReal))==0 ) return 1;
 173   memcpy(&tmp, p, sizeof(tmp));
 174   vdbeMemRenderNum(sizeof(zBuf), zBuf, &tmp);
 175   z = p->z;
 176   i = j = 0;
 177   incr = 1;
 178   if( p->enc!=SQLITE_UTF8 ){
 179     incr = 2;
 180     if( p->enc==SQLITE_UTF16BE ) z++;
 181   }
 182   while( zBuf[j] ){
 183     if( zBuf[j++]!=z[i] ) return 0;
 184     i += incr;
 185   }
 186   return 1;
 187 }
 188 #endif /* SQLITE_DEBUG */
 189
 190 /*
 191 ** If pMem is an object with a valid string representation, this routine
 192 ** ensures the internal encoding for the string representation is
 193 ** 'desiredEnc', one of SQLITE_UTF8, SQLITE_UTF16LE or SQLITE_UTF16BE.
 194 **
 195 ** If pMem is not a string object, or the encoding of the string
 196 ** representation is already stored using the requested encoding, then this
 197 ** routine is a no-op.
 198 **
 199 ** SQLITE_OK is returned if the conversion is successful (or not required).
 200 ** SQLITE_NOMEM may be returned if a malloc() fails during conversion
 201 ** between formats.
 202 */
 203 int sqlite3VdbeChangeEncoding(Mem *pMem, int desiredEnc){
 204 #ifndef SQLITE_OMIT_UTF16
 205   int rc;
 206 #endif
 207   assert( pMem!=0 );
 208   assert( !sqlite3VdbeMemIsRowSet(pMem) );
 209   assert( desiredEnc==SQLITE_UTF8 || desiredEnc==SQLITE_UTF16LE
 210            || desiredEnc==SQLITE_UTF16BE );
 211   if( !(pMem->flags&MEM_Str) ){
 212     pMem->enc = desiredEnc;
 213     return SQLITE_OK;
 214   }
 215   if( pMem->enc==desiredEnc ){
 216     return SQLITE_OK;
 217   }
 218   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 219 #ifdef SQLITE_OMIT_UTF16
 220   return SQLITE_ERROR;
 221 #else
 222
 223   /* MemTranslate() may return SQLITE_OK or SQLITE_NOMEM. If NOMEM is returned,
 224   ** then the encoding of the value may not have changed.
 225   */
 226   rc = sqlite3VdbeMemTranslate(pMem, (u8)desiredEnc);
 227   assert(rc==SQLITE_OK    || rc==SQLITE_NOMEM);
 228   assert(rc==SQLITE_OK    || pMem->enc!=desiredEnc);
 229   assert(rc==SQLITE_NOMEM || pMem->enc==desiredEnc);
 230   return rc;
 231 #endif
 232 }
 233
 234 /*
 235 ** Make sure pMem->z points to a writable allocation of at least n bytes.
 236 **
 237 ** If the bPreserve argument is true, then copy of the content of
 238 ** pMem->z into the new allocation.  pMem must be either a string or
 239 ** blob if bPreserve is true.  If bPreserve is false, any prior content
 240 ** in pMem->z is discarded.
 241 */
 242 SQLITE_NOINLINE int sqlite3VdbeMemGrow(Mem *pMem, int n, int bPreserve){
 243   assert( sqlite3VdbeCheckMemInvariants(pMem) );
 244   assert( !sqlite3VdbeMemIsRowSet(pMem) );
 245   testcase( pMem->db==0 );
 246
 247   /* If the bPreserve flag is set to true, then the memory cell must already
 248   ** contain a valid string or blob value.  */
 249   assert( bPreserve==0 || pMem->flags&(MEM_Blob|MEM_Str) );
 250   testcase( bPreserve && pMem->z==0 );
 251
 252   assert( pMem->szMalloc==0
 253        || (pMem->flags==MEM_Undefined
 254            && pMem->szMalloc<=sqlite3DbMallocSize(pMem->db,pMem->zMalloc))
 255        || pMem->szMalloc==sqlite3DbMallocSize(pMem->db,pMem->zMalloc));
 256   if( pMem->szMalloc>0 && bPreserve && pMem->z==pMem->zMalloc ){
 257     if( pMem->db ){
 258       pMem->z = pMem->zMalloc = sqlite3DbReallocOrFree(pMem->db, pMem->z, n);
 259     }else{
 260       pMem->zMalloc = sqlite3Realloc(pMem->z, n);
 261       if( pMem->zMalloc==0 ) sqlite3_free(pMem->z);
 262       pMem->z = pMem->zMalloc;
 263     }
 264     bPreserve = 0;
 265   }else{
 266     if( pMem->szMalloc>0 ) sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
 267     pMem->zMalloc = sqlite3DbMallocRaw(pMem->db, n);
 268   }
 269   if( pMem->zMalloc==0 ){
 270     sqlite3VdbeMemSetNull(pMem);
 271     pMem->z = 0;
 272     pMem->szMalloc = 0;
 273     return SQLITE_NOMEM_BKPT;
 274   }else{
 275     pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->zMalloc);
 276   }
 277
 278   if( bPreserve && pMem->z ){
 279     assert( pMem->z!=pMem->zMalloc );
 280     memcpy(pMem->zMalloc, pMem->z, pMem->n);
 281   }
 282   if( (pMem->flags&MEM_Dyn)!=0 ){
 283     assert( pMem->xDel!=0 && pMem->xDel!=SQLITE_DYNAMIC );
 284     pMem->xDel((void *)(pMem->z));
 285   }
 286
 287   pMem->z = pMem->zMalloc;
 288   pMem->flags &= ~(MEM_Dyn|MEM_Ephem|MEM_Static);
 289   return SQLITE_OK;
 290 }
 291
 292 /*
 293 ** Change the pMem->zMalloc allocation to be at least szNew bytes.
 294 ** If pMem->zMalloc already meets or exceeds the requested size, this
 295 ** routine is a no-op.
 296 **
 297 ** Any prior string or blob content in the pMem object may be discarded.
 298 ** The pMem->xDel destructor is called, if it exists.  Though MEM_Str
 299 ** and MEM_Blob values may be discarded, MEM_Int, MEM_Real, MEM_IntReal,
 300 ** and MEM_Null values are preserved.
 301 **
 302 ** Return SQLITE_OK on success or an error code (probably SQLITE_NOMEM)
 303 ** if unable to complete the resizing.
 304 */
 305 int sqlite3VdbeMemClearAndResize(Mem *pMem, int szNew){
 306   assert( CORRUPT_DB || szNew>0 );
 307   assert( (pMem->flags & MEM_Dyn)==0 || pMem->szMalloc==0 );
 308   if( pMem->szMalloc<szNew ){
 309     return sqlite3VdbeMemGrow(pMem, szNew, 0);
 310   }
 311   assert( (pMem->flags & MEM_Dyn)==0 );
 312   pMem->z = pMem->zMalloc;
 313   pMem->flags &= (MEM_Null|MEM_Int|MEM_Real|MEM_IntReal);
 314   return SQLITE_OK;
 315 }
 316
 317 /*
 318 ** It is already known that pMem contains an unterminated string.
 319 ** Add the zero terminator.
 320 **
 321 ** Three bytes of zero are added.  In this way, there is guaranteed
 322 ** to be a double-zero byte at an even byte boundary in order to
 323 ** terminate a UTF16 string, even if the initial size of the buffer
 324 ** is an odd number of bytes.
 325 */
 326 static SQLITE_NOINLINE int vdbeMemAddTerminator(Mem *pMem){
 327   if( sqlite3VdbeMemGrow(pMem, pMem->n+3, 1) ){
 328     return SQLITE_NOMEM_BKPT;
 329   }
 330   pMem->z[pMem->n] = 0;
 331   pMem->z[pMem->n+1] = 0;
 332   pMem->z[pMem->n+2] = 0;
 333   pMem->flags |= MEM_Term;
 334   return SQLITE_OK;
 335 }
 336
 337 /*
 338 ** Change pMem so that its MEM_Str or MEM_Blob value is stored in
 339 ** MEM.zMalloc, where it can be safely written.
 340 **
 341 ** Return SQLITE_OK on success or SQLITE_NOMEM if malloc fails.
 342 */
 343 int sqlite3VdbeMemMakeWriteable(Mem *pMem){
 344   assert( pMem!=0 );
 345   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 346   assert( !sqlite3VdbeMemIsRowSet(pMem) );
 347   if( (pMem->flags & (MEM_Str|MEM_Blob))!=0 ){
 348     if( ExpandBlob(pMem) ) return SQLITE_NOMEM;
 349     if( pMem->szMalloc==0 || pMem->z!=pMem->zMalloc ){
 350       int rc = vdbeMemAddTerminator(pMem);
 351       if( rc ) return rc;
 352     }
 353   }
 354   pMem->flags &= ~MEM_Ephem;
 355 #ifdef SQLITE_DEBUG
 356   pMem->pScopyFrom = 0;
 357 #endif
 358
 359   return SQLITE_OK;
 360 }
 361
 362 /*
 363 ** If the given Mem* has a zero-filled tail, turn it into an ordinary
 364 ** blob stored in dynamically allocated space.
 365 */
 366 #ifndef SQLITE_OMIT_INCRBLOB
 367 int sqlite3VdbeMemExpandBlob(Mem *pMem){
 368   int nByte;
 369   assert( pMem!=0 );
 370   assert( pMem->flags & MEM_Zero );
 371   assert( (pMem->flags&MEM_Blob)!=0 || MemNullNochng(pMem) );
 372   testcase( sqlite3_value_nochange(pMem) );
 373   assert( !sqlite3VdbeMemIsRowSet(pMem) );
 374   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 375
 376   /* Set nByte to the number of bytes required to store the expanded blob. */
 377   nByte = pMem->n + pMem->u.nZero;
 378   if( nByte<=0 ){
 379     if( (pMem->flags & MEM_Blob)==0 ) return SQLITE_OK;
 380     nByte = 1;
 381   }
 382   if( sqlite3VdbeMemGrow(pMem, nByte, 1) ){
 383     return SQLITE_NOMEM_BKPT;
 384   }
 385   assert( pMem->z!=0 );
 386   assert( sqlite3DbMallocSize(pMem->db,pMem->z) >= nByte );
 387
 388   memset(&pMem->z[pMem->n], 0, pMem->u.nZero);
 389   pMem->n += pMem->u.nZero;
 390   pMem->flags &= ~(MEM_Zero|MEM_Term);
 391   return SQLITE_OK;
 392 }
 393 #endif
 394
 395 /*
 396 ** Make sure the given Mem is \u0000 terminated.
 397 */
 398 int sqlite3VdbeMemNulTerminate(Mem *pMem){
 399   assert( pMem!=0 );
 400   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 401   testcase( (pMem->flags & (MEM_Term|MEM_Str))==(MEM_Term|MEM_Str) );
 402   testcase( (pMem->flags & (MEM_Term|MEM_Str))==0 );
 403   if( (pMem->flags & (MEM_Term|MEM_Str))!=MEM_Str ){
 404     return SQLITE_OK;   /* Nothing to do */
 405   }else{
 406     return vdbeMemAddTerminator(pMem);
 407   }
 408 }
 409
 410 /*
 411 ** Add MEM_Str to the set of representations for the given Mem.  This
 412 ** routine is only called if pMem is a number of some kind, not a NULL
 413 ** or a BLOB.
 414 **
 415 ** Existing representations MEM_Int, MEM_Real, or MEM_IntReal are invalidated
 416 ** if bForce is true but are retained if bForce is false.
 417 **
 418 ** A MEM_Null value will never be passed to this function. This function is
 419 ** used for converting values to text for returning to the user (i.e. via
 420 ** sqlite3_value_text()), or for ensuring that values to be used as btree
 421 ** keys are strings. In the former case a NULL pointer is returned the
 422 ** user and the latter is an internal programming error.
 423 */
 424 int sqlite3VdbeMemStringify(Mem *pMem, u8 enc, u8 bForce){
 425   const int nByte = 32;
 426
 427   assert( pMem!=0 );
 428   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 429   assert( !(pMem->flags&MEM_Zero) );
 430   assert( !(pMem->flags&(MEM_Str|MEM_Blob)) );
 431   assert( pMem->flags&(MEM_Int|MEM_Real|MEM_IntReal) );
 432   assert( !sqlite3VdbeMemIsRowSet(pMem) );
 433   assert( EIGHT_BYTE_ALIGNMENT(pMem) );
 434
 435
 436   if( sqlite3VdbeMemClearAndResize(pMem, nByte) ){
 437     pMem->enc = 0;
 438     return SQLITE_NOMEM_BKPT;
 439   }
 440
 441   vdbeMemRenderNum(nByte, pMem->z, pMem);
 442   assert( pMem->z!=0 );
 443   assert( pMem->n==(int)sqlite3Strlen30NN(pMem->z) );
 444   pMem->enc = SQLITE_UTF8;
 445   pMem->flags |= MEM_Str|MEM_Term;
 446   if( bForce ) pMem->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal);
 447   sqlite3VdbeChangeEncoding(pMem, enc);
 448   return SQLITE_OK;
 449 }
 450
 451 /*
 452 ** Memory cell pMem contains the context of an aggregate function.
 453 ** This routine calls the finalize method for that function.  The
 454 ** result of the aggregate is stored back into pMem.
 455 **
 456 ** Return SQLITE_ERROR if the finalizer reports an error.  SQLITE_OK
 457 ** otherwise.
 458 */
 459 int sqlite3VdbeMemFinalize(Mem *pMem, FuncDef *pFunc){
 460   sqlite3_context ctx;
 461   Mem t;
 462   assert( pFunc!=0 );
 463   assert( pMem!=0 );
 464   assert( pMem->db!=0 );
 465   assert( pFunc->xFinalize!=0 );
 466   assert( (pMem->flags & MEM_Null)!=0 || pFunc==pMem->u.pDef );
 467   assert( sqlite3_mutex_held(pMem->db->mutex) );
 468   memset(&ctx, 0, sizeof(ctx));
 469   memset(&t, 0, sizeof(t));
 470   t.flags = MEM_Null;
 471   t.db = pMem->db;
 472   ctx.pOut = &t;
 473   ctx.pMem = pMem;
 474   ctx.pFunc = pFunc;
 475   ctx.enc = ENC(t.db);
 476   pFunc->xFinalize(&ctx); /* IMP: R-24505-23230 */
 477   assert( (pMem->flags & MEM_Dyn)==0 );
 478   if( pMem->szMalloc>0 ) sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
 479   memcpy(pMem, &t, sizeof(t));
 480   return ctx.isError;
 481 }
 482
 483 /*
 484 ** Memory cell pAccum contains the context of an aggregate function.
 485 ** This routine calls the xValue method for that function and stores
 486 ** the results in memory cell pMem.
 487 **
 488 ** SQLITE_ERROR is returned if xValue() reports an error. SQLITE_OK
 489 ** otherwise.
 490 */
 491 #ifndef SQLITE_OMIT_WINDOWFUNC
 492 int sqlite3VdbeMemAggValue(Mem *pAccum, Mem *pOut, FuncDef *pFunc){
 493   sqlite3_context ctx;
 494   assert( pFunc!=0 );
 495   assert( pFunc->xValue!=0 );
 496   assert( (pAccum->flags & MEM_Null)!=0 || pFunc==pAccum->u.pDef );
 497   assert( pAccum->db!=0 );
 498   assert( sqlite3_mutex_held(pAccum->db->mutex) );
 499   memset(&ctx, 0, sizeof(ctx));
 500   sqlite3VdbeMemSetNull(pOut);
 501   ctx.pOut = pOut;
 502   ctx.pMem = pAccum;
 503   ctx.pFunc = pFunc;
 504   ctx.enc = ENC(pAccum->db);
 505   pFunc->xValue(&ctx);
 506   return ctx.isError;
 507 }
 508 #endif /* SQLITE_OMIT_WINDOWFUNC */
 509
 510 /*
 511 ** If the memory cell contains a value that must be freed by
 512 ** invoking the external callback in Mem.xDel, then this routine
 513 ** will free that value.  It also sets Mem.flags to MEM_Null.
 514 **
 515 ** This is a helper routine for sqlite3VdbeMemSetNull() and
 516 ** for sqlite3VdbeMemRelease().  Use those other routines as the
 517 ** entry point for releasing Mem resources.
 518 */
 519 static SQLITE_NOINLINE void vdbeMemClearExternAndSetNull(Mem *p){
 520   assert( p->db==0 || sqlite3_mutex_held(p->db->mutex) );
 521   assert( VdbeMemDynamic(p) );
 522   if( p->flags&MEM_Agg ){
 523     sqlite3VdbeMemFinalize(p, p->u.pDef);
 524     assert( (p->flags & MEM_Agg)==0 );
 525     testcase( p->flags & MEM_Dyn );
 526   }
 527   if( p->flags&MEM_Dyn ){
 528     assert( p->xDel!=SQLITE_DYNAMIC && p->xDel!=0 );
 529     p->xDel((void *)p->z);
 530   }
 531   p->flags = MEM_Null;
 532 }
 533
 534 /*
 535 ** Release memory held by the Mem p, both external memory cleared
 536 ** by p->xDel and memory in p->zMalloc.
 537 **
 538 ** This is a helper routine invoked by sqlite3VdbeMemRelease() in
 539 ** the unusual case where there really is memory in p that needs
 540 ** to be freed.
 541 */
 542 static SQLITE_NOINLINE void vdbeMemClear(Mem *p){
 543   if( VdbeMemDynamic(p) ){
 544     vdbeMemClearExternAndSetNull(p);
 545   }
 546   if( p->szMalloc ){
 547     sqlite3DbFreeNN(p->db, p->zMalloc);
 548     p->szMalloc = 0;
 549   }
 550   p->z = 0;
 551 }
 552
 553 /*
 554 ** Release any memory resources held by the Mem.  Both the memory that is
 555 ** free by Mem.xDel and the Mem.zMalloc allocation are freed.
 556 **
 557 ** Use this routine prior to clean up prior to abandoning a Mem, or to
 558 ** reset a Mem back to its minimum memory utilization.
 559 **
 560 ** Use sqlite3VdbeMemSetNull() to release just the Mem.xDel space
 561 ** prior to inserting new content into the Mem.
 562 */
 563 void sqlite3VdbeMemRelease(Mem *p){
 564   assert( sqlite3VdbeCheckMemInvariants(p) );
 565   if( VdbeMemDynamic(p) || p->szMalloc ){
 566     vdbeMemClear(p);
 567   }
 568 }
 569
 570 /* Like sqlite3VdbeMemRelease() but faster for cases where we
 571 ** know in advance that the Mem is not MEM_Dyn or MEM_Agg.
 572 */
 573 void sqlite3VdbeMemReleaseMalloc(Mem *p){
 574   assert( !VdbeMemDynamic(p) );
 575   if( p->szMalloc ) vdbeMemClear(p);
 576 }
 577
 578 /*
 579 ** Convert a 64-bit IEEE double into a 64-bit signed integer.
 580 ** If the double is out of range of a 64-bit signed integer then
 581 ** return the closest available 64-bit signed integer.
 582 */
 583 static SQLITE_NOINLINE i64 doubleToInt64(double r){
 584 #ifdef SQLITE_OMIT_FLOATING_POINT
 585   /* When floating-point is omitted, double and int64 are the same thing */
 586   return r;
 587 #else
 588   /*
 589   ** Many compilers we encounter do not define constants for the
 590   ** minimum and maximum 64-bit integers, or they define them
 591   ** inconsistently.  And many do not understand the "LL" notation.
 592   ** So we define our own static constants here using nothing
 593   ** larger than a 32-bit integer constant.
 594   */
 595   static const i64 maxInt = LARGEST_INT64;
 596   static const i64 minInt = SMALLEST_INT64;
 597
 598   if( r<=(double)minInt ){
 599     return minInt;
 600   }else if( r>=(double)maxInt ){
 601     return maxInt;
 602   }else{
 603     return (i64)r;
 604   }
 605 #endif
 606 }
 607
 608 /*
 609 ** Return some kind of integer value which is the best we can do
 610 ** at representing the value that *pMem describes as an integer.
 611 ** If pMem is an integer, then the value is exact.  If pMem is
 612 ** a floating-point then the value returned is the integer part.
 613 ** If pMem is a string or blob, then we make an attempt to convert
 614 ** it into an integer and return that.  If pMem represents an
 615 ** an SQL-NULL value, return 0.
 616 **
 617 ** If pMem represents a string value, its encoding might be changed.
 618 */
 619 static SQLITE_NOINLINE i64 memIntValue(const Mem *pMem){
 620   i64 value = 0;
 621   sqlite3Atoi64(pMem->z, &value, pMem->n, pMem->enc);
 622   return value;
 623 }
 624 i64 sqlite3VdbeIntValue(const Mem *pMem){
 625   int flags;
 626   assert( pMem!=0 );
 627   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 628   assert( EIGHT_BYTE_ALIGNMENT(pMem) );
 629   flags = pMem->flags;
 630   if( flags & (MEM_Int|MEM_IntReal) ){
 631     testcase( flags & MEM_IntReal );
 632     return pMem->u.i;
 633   }else if( flags & MEM_Real ){
 634     return doubleToInt64(pMem->u.r);
 635   }else if( (flags & (MEM_Str|MEM_Blob))!=0 && pMem->z!=0 ){
 636     return memIntValue(pMem);
 637   }else{
 638     return 0;
 639   }
 640 }
 641
 642 /*
 643 ** Return the best representation of pMem that we can get into a
 644 ** double.  If pMem is already a double or an integer, return its
 645 ** value.  If it is a string or blob, try to convert it to a double.
 646 ** If it is a NULL, return 0.0.
 647 */
 648 static SQLITE_NOINLINE double memRealValue(Mem *pMem){
 649   /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
 650   double val = (double)0;
 651   sqlite3AtoF(pMem->z, &val, pMem->n, pMem->enc);
 652   return val;
 653 }
 654 double sqlite3VdbeRealValue(Mem *pMem){
 655   assert( pMem!=0 );
 656   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 657   assert( EIGHT_BYTE_ALIGNMENT(pMem) );
 658   if( pMem->flags & MEM_Real ){
 659     return pMem->u.r;
 660   }else if( pMem->flags & (MEM_Int|MEM_IntReal) ){
 661     testcase( pMem->flags & MEM_IntReal );
 662     return (double)pMem->u.i;
 663   }else if( pMem->flags & (MEM_Str|MEM_Blob) ){
 664     return memRealValue(pMem);
 665   }else{
 666     /* (double)0 In case of SQLITE_OMIT_FLOATING_POINT... */
 667     return (double)0;
 668   }
 669 }
 670
 671 /*
 672 ** Return 1 if pMem represents true, and return 0 if pMem represents false.
 673 ** Return the value ifNull if pMem is NULL.
 674 */
 675 int sqlite3VdbeBooleanValue(Mem *pMem, int ifNull){
 676   testcase( pMem->flags & MEM_IntReal );
 677   if( pMem->flags & (MEM_Int|MEM_IntReal) ) return pMem->u.i!=0;
 678   if( pMem->flags & MEM_Null ) return ifNull;
 679   return sqlite3VdbeRealValue(pMem)!=0.0;
 680 }
 681
 682 /*
 683 ** The MEM structure is already a MEM_Real or MEM_IntReal. Try to
 684 ** make it a MEM_Int if we can.
 685 */
 686 void sqlite3VdbeIntegerAffinity(Mem *pMem){
 687   assert( pMem!=0 );
 688   assert( pMem->flags & (MEM_Real|MEM_IntReal) );
 689   assert( !sqlite3VdbeMemIsRowSet(pMem) );
 690   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 691   assert( EIGHT_BYTE_ALIGNMENT(pMem) );
 692
 693   if( pMem->flags & MEM_IntReal ){
 694     MemSetTypeFlag(pMem, MEM_Int);
 695   }else{
 696     i64 ix = doubleToInt64(pMem->u.r);
 697
 698     /* Only mark the value as an integer if
 699     **
 700     **    (1) the round-trip conversion real->int->real is a no-op, and
 701     **    (2) The integer is neither the largest nor the smallest
 702     **        possible integer (ticket #3922)
 703     **
 704     ** The second and third terms in the following conditional enforces
 705     ** the second condition under the assumption that addition overflow causes
 706     ** values to wrap around.
 707     */
 708     if( pMem->u.r==ix && ix>SMALLEST_INT64 && ix<LARGEST_INT64 ){
 709       pMem->u.i = ix;
 710       MemSetTypeFlag(pMem, MEM_Int);
 711     }
 712   }
 713 }
 714
 715 /*
 716 ** Convert pMem to type integer.  Invalidate any prior representations.
 717 */
 718 int sqlite3VdbeMemIntegerify(Mem *pMem){
 719   assert( pMem!=0 );
 720   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 721   assert( !sqlite3VdbeMemIsRowSet(pMem) );
 722   assert( EIGHT_BYTE_ALIGNMENT(pMem) );
 723
 724   pMem->u.i = sqlite3VdbeIntValue(pMem);
 725   MemSetTypeFlag(pMem, MEM_Int);
 726   return SQLITE_OK;
 727 }
 728
 729 /*
 730 ** Convert pMem so that it is of type MEM_Real.
 731 ** Invalidate any prior representations.
 732 */
 733 int sqlite3VdbeMemRealify(Mem *pMem){
 734   assert( pMem!=0 );
 735   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 736   assert( EIGHT_BYTE_ALIGNMENT(pMem) );
 737
 738   pMem->u.r = sqlite3VdbeRealValue(pMem);
 739   MemSetTypeFlag(pMem, MEM_Real);
 740   return SQLITE_OK;
 741 }
 742
 743 /* Compare a floating point value to an integer.  Return true if the two
 744 ** values are the same within the precision of the floating point value.
 745 **
 746 ** This function assumes that i was obtained by assignment from r1.
 747 **
 748 ** For some versions of GCC on 32-bit machines, if you do the more obvious
 749 ** comparison of "r1==(double)i" you sometimes get an answer of false even
 750 ** though the r1 and (double)i values are bit-for-bit the same.
 751 */
 752 int sqlite3RealSameAsInt(double r1, sqlite3_int64 i){
 753   double r2 = (double)i;
 754   return r1==0.0
 755       || (memcmp(&r1, &r2, sizeof(r1))==0
 756           && i >= -2251799813685248LL && i < 2251799813685248LL);
 757 }
 758
 759 /* Convert a floating point value to its closest integer.  Do so in
 760 ** a way that avoids 'outside the range of representable values' warnings
 761 ** from UBSAN.
 762 */
 763 i64 sqlite3RealToI64(double r){
 764   if( r<=(double)SMALLEST_INT64 ) return SMALLEST_INT64;
 765   if( r>=(double)LARGEST_INT64) return LARGEST_INT64;
 766   return (i64)r;
 767 }
 768
 769 /*
 770 ** Convert pMem so that it has type MEM_Real or MEM_Int.
 771 ** Invalidate any prior representations.
 772 **
 773 ** Every effort is made to force the conversion, even if the input
 774 ** is a string that does not look completely like a number.  Convert
 775 ** as much of the string as we can and ignore the rest.
 776 */
 777 int sqlite3VdbeMemNumerify(Mem *pMem){
 778   assert( pMem!=0 );
 779   testcase( pMem->flags & MEM_Int );
 780   testcase( pMem->flags & MEM_Real );
 781   testcase( pMem->flags & MEM_IntReal );
 782   testcase( pMem->flags & MEM_Null );
 783   if( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null))==0 ){
 784     int rc;
 785     sqlite3_int64 ix;
 786     assert( (pMem->flags & (MEM_Blob|MEM_Str))!=0 );
 787     assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
 788     rc = sqlite3AtoF(pMem->z, &pMem->u.r, pMem->n, pMem->enc);
 789     if( ((rc==0 || rc==1) && sqlite3Atoi64(pMem->z, &ix, pMem->n, pMem->enc)<=1)
 790      || sqlite3RealSameAsInt(pMem->u.r, (ix = sqlite3RealToI64(pMem->u.r)))
 791     ){
 792       pMem->u.i = ix;
 793       MemSetTypeFlag(pMem, MEM_Int);
 794     }else{
 795       MemSetTypeFlag(pMem, MEM_Real);
 796     }
 797   }
 798   assert( (pMem->flags & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Null))!=0 );
 799   pMem->flags &= ~(MEM_Str|MEM_Blob|MEM_Zero);
 800   return SQLITE_OK;
 801 }
 802
 803 /*
 804 ** Cast the datatype of the value in pMem according to the affinity
 805 ** "aff".  Casting is different from applying affinity in that a cast
 806 ** is forced.  In other words, the value is converted into the desired
 807 ** affinity even if that results in loss of data.  This routine is
 808 ** used (for example) to implement the SQL "cast()" operator.
 809 */
 810 int sqlite3VdbeMemCast(Mem *pMem, u8 aff, u8 encoding){
 811   if( pMem->flags & MEM_Null ) return SQLITE_OK;
 812   switch( aff ){
 813     case SQLITE_AFF_BLOB: {   /* Really a cast to BLOB */
 814       if( (pMem->flags & MEM_Blob)==0 ){
 815         sqlite3ValueApplyAffinity(pMem, SQLITE_AFF_TEXT, encoding);
 816         assert( pMem->flags & MEM_Str || pMem->db->mallocFailed );
 817         if( pMem->flags & MEM_Str ) MemSetTypeFlag(pMem, MEM_Blob);
 818       }else{
 819         pMem->flags &= ~(MEM_TypeMask&~MEM_Blob);
 820       }
 821       break;
 822     }
 823     case SQLITE_AFF_NUMERIC: {
 824       sqlite3VdbeMemNumerify(pMem);
 825       break;
 826     }
 827     case SQLITE_AFF_INTEGER: {
 828       sqlite3VdbeMemIntegerify(pMem);
 829       break;
 830     }
 831     case SQLITE_AFF_REAL: {
 832       sqlite3VdbeMemRealify(pMem);
 833       break;
 834     }
 835     default: {
 836       assert( aff==SQLITE_AFF_TEXT );
 837       assert( MEM_Str==(MEM_Blob>>3) );
 838       pMem->flags |= (pMem->flags&MEM_Blob)>>3;
 839       sqlite3ValueApplyAffinity(pMem, SQLITE_AFF_TEXT, encoding);
 840       assert( pMem->flags & MEM_Str || pMem->db->mallocFailed );
 841       pMem->flags &= ~(MEM_Int|MEM_Real|MEM_IntReal|MEM_Blob|MEM_Zero);
 842       if( encoding!=SQLITE_UTF8 ) pMem->n &= ~1;
 843       return sqlite3VdbeChangeEncoding(pMem, encoding);
 844     }
 845   }
 846   return SQLITE_OK;
 847 }
 848
 849 /*
 850 ** Initialize bulk memory to be a consistent Mem object.
 851 **
 852 ** The minimum amount of initialization feasible is performed.
 853 */
 854 void sqlite3VdbeMemInit(Mem *pMem, sqlite3 *db, u16 flags){
 855   assert( (flags & ~MEM_TypeMask)==0 );
 856   pMem->flags = flags;
 857   pMem->db = db;
 858   pMem->szMalloc = 0;
 859 }
 860
 861
 862 /*
 863 ** Delete any previous value and set the value stored in *pMem to NULL.
 864 **
 865 ** This routine calls the Mem.xDel destructor to dispose of values that
 866 ** require the destructor.  But it preserves the Mem.zMalloc memory allocation.
 867 ** To free all resources, use sqlite3VdbeMemRelease(), which both calls this
 868 ** routine to invoke the destructor and deallocates Mem.zMalloc.
 869 **
 870 ** Use this routine to reset the Mem prior to insert a new value.
 871 **
 872 ** Use sqlite3VdbeMemRelease() to complete erase the Mem prior to abandoning it.
 873 */
 874 void sqlite3VdbeMemSetNull(Mem *pMem){
 875   if( VdbeMemDynamic(pMem) ){
 876     vdbeMemClearExternAndSetNull(pMem);
 877   }else{
 878     pMem->flags = MEM_Null;
 879   }
 880 }
 881 void sqlite3ValueSetNull(sqlite3_value *p){
 882   sqlite3VdbeMemSetNull((Mem*)p);
 883 }
 884
 885 /*
 886 ** Delete any previous value and set the value to be a BLOB of length
 887 ** n containing all zeros.
 888 */
 889 #ifndef SQLITE_OMIT_INCRBLOB
 890 void sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
 891   sqlite3VdbeMemRelease(pMem);
 892   pMem->flags = MEM_Blob|MEM_Zero;
 893   pMem->n = 0;
 894   if( n<0 ) n = 0;
 895   pMem->u.nZero = n;
 896   pMem->enc = SQLITE_UTF8;
 897   pMem->z = 0;
 898 }
 899 #else
 900 int sqlite3VdbeMemSetZeroBlob(Mem *pMem, int n){
 901   int nByte = n>0?n:1;
 902   if( sqlite3VdbeMemGrow(pMem, nByte, 0) ){
 903     return SQLITE_NOMEM_BKPT;
 904   }
 905   assert( pMem->z!=0 );
 906   assert( sqlite3DbMallocSize(pMem->db, pMem->z)>=nByte );
 907   memset(pMem->z, 0, nByte);
 908   pMem->n = n>0?n:0;
 909   pMem->flags = MEM_Blob;
 910   pMem->enc = SQLITE_UTF8;
 911   return SQLITE_OK;
 912 }
 913 #endif
 914
 915 /*
 916 ** The pMem is known to contain content that needs to be destroyed prior
 917 ** to a value change.  So invoke the destructor, then set the value to
 918 ** a 64-bit integer.
 919 */
 920 static SQLITE_NOINLINE void vdbeReleaseAndSetInt64(Mem *pMem, i64 val){
 921   sqlite3VdbeMemSetNull(pMem);
 922   pMem->u.i = val;
 923   pMem->flags = MEM_Int;
 924 }
 925
 926 /*
 927 ** Delete any previous value and set the value stored in *pMem to val,
 928 ** manifest type INTEGER.
 929 */
 930 void sqlite3VdbeMemSetInt64(Mem *pMem, i64 val){
 931   if( VdbeMemDynamic(pMem) ){
 932     vdbeReleaseAndSetInt64(pMem, val);
 933   }else{
 934     pMem->u.i = val;
 935     pMem->flags = MEM_Int;
 936   }
 937 }
 938
 939 /* A no-op destructor */
 940 void sqlite3NoopDestructor(void *p){ UNUSED_PARAMETER(p); }
 941
 942 /*
 943 ** Set the value stored in *pMem should already be a NULL.
 944 ** Also store a pointer to go with it.
 945 */
 946 void sqlite3VdbeMemSetPointer(
 947   Mem *pMem,
 948   void *pPtr,
 949   const char *zPType,
 950   void (*xDestructor)(void*)
 951 ){
 952   assert( pMem->flags==MEM_Null );
 953   vdbeMemClear(pMem);
 954   pMem->u.zPType = zPType ? zPType : "";
 955   pMem->z = pPtr;
 956   pMem->flags = MEM_Null|MEM_Dyn|MEM_Subtype|MEM_Term;
 957   pMem->eSubtype = 'p';
 958   pMem->xDel = xDestructor ? xDestructor : sqlite3NoopDestructor;
 959 }
 960
 961 #ifndef SQLITE_OMIT_FLOATING_POINT
 962 /*
 963 ** Delete any previous value and set the value stored in *pMem to val,
 964 ** manifest type REAL.
 965 */
 966 void sqlite3VdbeMemSetDouble(Mem *pMem, double val){
 967   sqlite3VdbeMemSetNull(pMem);
 968   if( !sqlite3IsNaN(val) ){
 969     pMem->u.r = val;
 970     pMem->flags = MEM_Real;
 971   }
 972 }
 973 #endif
 974
 975 #ifdef SQLITE_DEBUG
 976 /*
 977 ** Return true if the Mem holds a RowSet object.  This routine is intended
 978 ** for use inside of assert() statements.
 979 */
 980 int sqlite3VdbeMemIsRowSet(const Mem *pMem){
 981   return (pMem->flags&(MEM_Blob|MEM_Dyn))==(MEM_Blob|MEM_Dyn)
 982          && pMem->xDel==sqlite3RowSetDelete;
 983 }
 984 #endif
 985
 986 /*
 987 ** Delete any previous value and set the value of pMem to be an
 988 ** empty boolean index.
 989 **
 990 ** Return SQLITE_OK on success and SQLITE_NOMEM if a memory allocation
 991 ** error occurs.
 992 */
 993 int sqlite3VdbeMemSetRowSet(Mem *pMem){
 994   sqlite3 *db = pMem->db;
 995   RowSet *p;
 996   assert( db!=0 );
 997   assert( !sqlite3VdbeMemIsRowSet(pMem) );
 998   sqlite3VdbeMemRelease(pMem);
 999   p = sqlite3RowSetInit(db);
1000   if( p==0 ) return SQLITE_NOMEM;
1001   pMem->z = (char*)p;
1002   pMem->flags = MEM_Blob|MEM_Dyn;
1003   pMem->xDel = sqlite3RowSetDelete;
1004   return SQLITE_OK;
1005 }
1006
1007 /*
1008 ** Return true if the Mem object contains a TEXT or BLOB that is
1009 ** too large - whose size exceeds SQLITE_MAX_LENGTH.
1010 */
1011 int sqlite3VdbeMemTooBig(Mem *p){
1012   assert( p->db!=0 );
1013   if( p->flags & (MEM_Str|MEM_Blob) ){
1014     int n = p->n;
1015     if( p->flags & MEM_Zero ){
1016       n += p->u.nZero;
1017     }
1018     return n>p->db->aLimit[SQLITE_LIMIT_LENGTH];
1019   }
1020   return 0;
1021 }
1022
1023 #ifdef SQLITE_DEBUG
1024 /*
1025 ** This routine prepares a memory cell for modification by breaking
1026 ** its link to a shallow copy and by marking any current shallow
1027 ** copies of this cell as invalid.
1028 **
1029 ** This is used for testing and debugging only - to help ensure that shallow
1030 ** copies (created by OP_SCopy) are not misused.
1031 */
1032 void sqlite3VdbeMemAboutToChange(Vdbe *pVdbe, Mem *pMem){
1033   int i;
1034   Mem *pX;
1035   for(i=1, pX=pVdbe->aMem+1; i<pVdbe->nMem; i++, pX++){
1036     if( pX->pScopyFrom==pMem ){
1037       u16 mFlags;
1038       if( pVdbe->db->flags & SQLITE_VdbeTrace ){
1039         sqlite3DebugPrintf("Invalidate R[%d] due to change in R[%d]\n",
1040           (int)(pX - pVdbe->aMem), (int)(pMem - pVdbe->aMem));
1041       }
1042       /* If pX is marked as a shallow copy of pMem, then try to verify that
1043       ** no significant changes have been made to pX since the OP_SCopy.
1044       ** A significant change would indicated a missed call to this
1045       ** function for pX.  Minor changes, such as adding or removing a
1046       ** dual type, are allowed, as long as the underlying value is the
1047       ** same. */
1048       mFlags = pMem->flags & pX->flags & pX->mScopyFlags;
1049       assert( (mFlags&(MEM_Int|MEM_IntReal))==0 || pMem->u.i==pX->u.i );
1050
1051       /* pMem is the register that is changing.  But also mark pX as
1052       ** undefined so that we can quickly detect the shallow-copy error */
1053       pX->flags = MEM_Undefined;
1054       pX->pScopyFrom = 0;
1055     }
1056   }
1057   pMem->pScopyFrom = 0;
1058 }
1059 #endif /* SQLITE_DEBUG */
1060
1061 /*
1062 ** Make an shallow copy of pFrom into pTo.  Prior contents of
1063 ** pTo are freed.  The pFrom->z field is not duplicated.  If
1064 ** pFrom->z is used, then pTo->z points to the same thing as pFrom->z
1065 ** and flags gets srcType (either MEM_Ephem or MEM_Static).
1066 */
1067 static SQLITE_NOINLINE void vdbeClrCopy(Mem *pTo, const Mem *pFrom, int eType){
1068   vdbeMemClearExternAndSetNull(pTo);
1069   assert( !VdbeMemDynamic(pTo) );
1070   sqlite3VdbeMemShallowCopy(pTo, pFrom, eType);
1071 }
1072 void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
1073   assert( !sqlite3VdbeMemIsRowSet(pFrom) );
1074   assert( pTo->db==pFrom->db );
1075   if( VdbeMemDynamic(pTo) ){ vdbeClrCopy(pTo,pFrom,srcType); return; }
1076   memcpy(pTo, pFrom, MEMCELLSIZE);
1077   if( (pFrom->flags&MEM_Static)==0 ){
1078     pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
1079     assert( srcType==MEM_Ephem || srcType==MEM_Static );
1080     pTo->flags |= srcType;
1081   }
1082 }
1083
1084 /*
1085 ** Make a full copy of pFrom into pTo.  Prior contents of pTo are
1086 ** freed before the copy is made.
1087 */
1088 int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
1089   int rc = SQLITE_OK;
1090
1091   assert( !sqlite3VdbeMemIsRowSet(pFrom) );
1092   if( VdbeMemDynamic(pTo) ) vdbeMemClearExternAndSetNull(pTo);
1093   memcpy(pTo, pFrom, MEMCELLSIZE);
1094   pTo->flags &= ~MEM_Dyn;
1095   if( pTo->flags&(MEM_Str|MEM_Blob) ){
1096     if( 0==(pFrom->flags&MEM_Static) ){
1097       pTo->flags |= MEM_Ephem;
1098       rc = sqlite3VdbeMemMakeWriteable(pTo);
1099     }
1100   }
1101
1102   return rc;
1103 }
1104
1105 /*
1106 ** Transfer the contents of pFrom to pTo. Any existing value in pTo is
1107 ** freed. If pFrom contains ephemeral data, a copy is made.
1108 **
1109 ** pFrom contains an SQL NULL when this routine returns.
1110 */
1111 void sqlite3VdbeMemMove(Mem *pTo, Mem *pFrom){
1112   assert( pFrom->db==0 || sqlite3_mutex_held(pFrom->db->mutex) );
1113   assert( pTo->db==0 || sqlite3_mutex_held(pTo->db->mutex) );
1114   assert( pFrom->db==0 || pTo->db==0 || pFrom->db==pTo->db );
1115
1116   sqlite3VdbeMemRelease(pTo);
1117   memcpy(pTo, pFrom, sizeof(Mem));
1118   pFrom->flags = MEM_Null;
1119   pFrom->szMalloc = 0;
1120 }
1121
1122 /*
1123 ** Change the value of a Mem to be a string or a BLOB.
1124 **
1125 ** The memory management strategy depends on the value of the xDel
1126 ** parameter. If the value passed is SQLITE_TRANSIENT, then the
1127 ** string is copied into a (possibly existing) buffer managed by the
1128 ** Mem structure. Otherwise, any existing buffer is freed and the
1129 ** pointer copied.
1130 **
1131 ** If the string is too large (if it exceeds the SQLITE_LIMIT_LENGTH
1132 ** size limit) then no memory allocation occurs.  If the string can be
1133 ** stored without allocating memory, then it is.  If a memory allocation
1134 ** is required to store the string, then value of pMem is unchanged.  In
1135 ** either case, SQLITE_TOOBIG is returned.
1136 **
1137 ** The "enc" parameter is the text encoding for the string, or zero
1138 ** to store a blob.
1139 **
1140 ** If n is negative, then the string consists of all bytes up to but
1141 ** excluding the first zero character.  The n parameter must be
1142 ** non-negative for blobs.
1143 */
1144 int sqlite3VdbeMemSetStr(
1145   Mem *pMem,          /* Memory cell to set to string value */
1146   const char *z,      /* String pointer */
1147   i64 n,              /* Bytes in string, or negative */
1148   u8 enc,             /* Encoding of z.  0 for BLOBs */
1149   void (*xDel)(void*) /* Destructor function */
1150 ){
1151   i64 nByte = n;      /* New value for pMem->n */
1152   int iLimit;         /* Maximum allowed string or blob size */
1153   u16 flags;          /* New value for pMem->flags */
1154
1155   assert( pMem!=0 );
1156   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
1157   assert( !sqlite3VdbeMemIsRowSet(pMem) );
1158   assert( enc!=0 || n>=0 );
1159
1160   /* If z is a NULL pointer, set pMem to contain an SQL NULL. */
1161   if( !z ){
1162     sqlite3VdbeMemSetNull(pMem);
1163     return SQLITE_OK;
1164   }
1165
1166   if( pMem->db ){
1167     iLimit = pMem->db->aLimit[SQLITE_LIMIT_LENGTH];
1168   }else{
1169     iLimit = SQLITE_MAX_LENGTH;
1170   }
1171   if( nByte<0 ){
1172     assert( enc!=0 );
1173     if( enc==SQLITE_UTF8 ){
1174       nByte = strlen(z);
1175     }else{
1176       for(nByte=0; nByte<=iLimit && (z[nByte] | z[nByte+1]); nByte+=2){}
1177     }
1178     flags= MEM_Str|MEM_Term;
1179   }else if( enc==0 ){
1180     flags = MEM_Blob;
1181     enc = SQLITE_UTF8;
1182   }else{
1183     flags = MEM_Str;
1184   }
1185   if( nByte>iLimit ){
1186     if( xDel && xDel!=SQLITE_TRANSIENT ){
1187       if( xDel==SQLITE_DYNAMIC ){
1188         sqlite3DbFree(pMem->db, (void*)z);
1189       }else{
1190         xDel((void*)z);
1191       }
1192     }
1193     sqlite3VdbeMemSetNull(pMem);
1194     return sqlite3ErrorToParser(pMem->db, SQLITE_TOOBIG);
1195   }
1196
1197   /* The following block sets the new values of Mem.z and Mem.xDel. It
1198   ** also sets a flag in local variable "flags" to indicate the memory
1199   ** management (one of MEM_Dyn or MEM_Static).
1200   */
1201   if( xDel==SQLITE_TRANSIENT ){
1202     i64 nAlloc = nByte;
1203     if( flags&MEM_Term ){
1204       nAlloc += (enc==SQLITE_UTF8?1:2);
1205     }
1206     testcase( nAlloc==0 );
1207     testcase( nAlloc==31 );
1208     testcase( nAlloc==32 );
1209     if( sqlite3VdbeMemClearAndResize(pMem, (int)MAX(nAlloc,32)) ){
1210       return SQLITE_NOMEM_BKPT;
1211     }
1212     memcpy(pMem->z, z, nAlloc);
1213   }else{
1214     sqlite3VdbeMemRelease(pMem);
1215     pMem->z = (char *)z;
1216     if( xDel==SQLITE_DYNAMIC ){
1217       pMem->zMalloc = pMem->z;
1218       pMem->szMalloc = sqlite3DbMallocSize(pMem->db, pMem->zMalloc);
1219     }else{
1220       pMem->xDel = xDel;
1221       flags |= ((xDel==SQLITE_STATIC)?MEM_Static:MEM_Dyn);
1222     }
1223   }
1224
1225   pMem->n = (int)(nByte & 0x7fffffff);
1226   pMem->flags = flags;
1227   pMem->enc = enc;
1228
1229 #ifndef SQLITE_OMIT_UTF16
1230   if( enc>SQLITE_UTF8 && sqlite3VdbeMemHandleBom(pMem) ){
1231     return SQLITE_NOMEM_BKPT;
1232   }
1233 #endif
1234
1235
1236   return SQLITE_OK;
1237 }
1238
1239 /*
1240 ** Move data out of a btree key or data field and into a Mem structure.
1241 ** The data is payload from the entry that pCur is currently pointing
1242 ** to.  offset and amt determine what portion of the data or key to retrieve.
1243 ** The result is written into the pMem element.
1244 **
1245 ** The pMem object must have been initialized.  This routine will use
1246 ** pMem->zMalloc to hold the content from the btree, if possible.  New
1247 ** pMem->zMalloc space will be allocated if necessary.  The calling routine
1248 ** is responsible for making sure that the pMem object is eventually
1249 ** destroyed.
1250 **
1251 ** If this routine fails for any reason (malloc returns NULL or unable
1252 ** to read from the disk) then the pMem is left in an inconsistent state.
1253 */
1254 int sqlite3VdbeMemFromBtree(
1255   BtCursor *pCur,   /* Cursor pointing at record to retrieve. */
1256   u32 offset,       /* Offset from the start of data to return bytes from. */
1257   u32 amt,          /* Number of bytes to return. */
1258   Mem *pMem         /* OUT: Return data in this Mem structure. */
1259 ){
1260   int rc;
1261   pMem->flags = MEM_Null;
1262   if( sqlite3BtreeMaxRecordSize(pCur)<offset+amt ){
1263     return SQLITE_CORRUPT_BKPT;
1264   }
1265   if( SQLITE_OK==(rc = sqlite3VdbeMemClearAndResize(pMem, amt+1)) ){
1266     rc = sqlite3BtreePayload(pCur, offset, amt, pMem->z);
1267     if( rc==SQLITE_OK ){
1268       pMem->z[amt] = 0;   /* Overrun area used when reading malformed records */
1269       pMem->flags = MEM_Blob;
1270       pMem->n = (int)amt;
1271     }else{
1272       sqlite3VdbeMemRelease(pMem);
1273     }
1274   }
1275   return rc;
1276 }
1277 int sqlite3VdbeMemFromBtreeZeroOffset(
1278   BtCursor *pCur,   /* Cursor pointing at record to retrieve. */
1279   u32 amt,          /* Number of bytes to return. */
1280   Mem *pMem         /* OUT: Return data in this Mem structure. */
1281 ){
1282   u32 available = 0;  /* Number of bytes available on the local btree page */
1283   int rc = SQLITE_OK; /* Return code */
1284
1285   assert( sqlite3BtreeCursorIsValid(pCur) );
1286   assert( !VdbeMemDynamic(pMem) );
1287
1288   /* Note: the calls to BtreeKeyFetch() and DataFetch() below assert()
1289   ** that both the BtShared and database handle mutexes are held. */
1290   assert( !sqlite3VdbeMemIsRowSet(pMem) );
1291   pMem->z = (char *)sqlite3BtreePayloadFetch(pCur, &available);
1292   assert( pMem->z!=0 );
1293
1294   if( amt<=available ){
1295     pMem->flags = MEM_Blob|MEM_Ephem;
1296     pMem->n = (int)amt;
1297   }else{
1298     rc = sqlite3VdbeMemFromBtree(pCur, 0, amt, pMem);
1299   }
1300
1301   return rc;
1302 }
1303
1304 /*
1305 ** The pVal argument is known to be a value other than NULL.
1306 ** Convert it into a string with encoding enc and return a pointer
1307 ** to a zero-terminated version of that string.
1308 */
1309 static SQLITE_NOINLINE const void *valueToText(sqlite3_value* pVal, u8 enc){
1310   assert( pVal!=0 );
1311   assert( pVal->db==0 || sqlite3_mutex_held(pVal->db->mutex) );
1312   assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );
1313   assert( !sqlite3VdbeMemIsRowSet(pVal) );
1314   assert( (pVal->flags & (MEM_Null))==0 );
1315   if( pVal->flags & (MEM_Blob|MEM_Str) ){
1316     if( ExpandBlob(pVal) ) return 0;
1317     pVal->flags |= MEM_Str;
1318     if( pVal->enc != (enc & ~SQLITE_UTF16_ALIGNED) ){
1319       sqlite3VdbeChangeEncoding(pVal, enc & ~SQLITE_UTF16_ALIGNED);
1320     }
1321     if( (enc & SQLITE_UTF16_ALIGNED)!=0 && 1==(1&SQLITE_PTR_TO_INT(pVal->z)) ){
1322       assert( (pVal->flags & (MEM_Ephem|MEM_Static))!=0 );
1323       if( sqlite3VdbeMemMakeWriteable(pVal)!=SQLITE_OK ){
1324         return 0;
1325       }
1326     }
1327     sqlite3VdbeMemNulTerminate(pVal); /* IMP: R-31275-44060 */
1328   }else{
1329     sqlite3VdbeMemStringify(pVal, enc, 0);
1330     assert( 0==(1&SQLITE_PTR_TO_INT(pVal->z)) );
1331   }
1332   assert(pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) || pVal->db==0
1333               || pVal->db->mallocFailed );
1334   if( pVal->enc==(enc & ~SQLITE_UTF16_ALIGNED) ){
1335     assert( sqlite3VdbeMemValidStrRep(pVal) );
1336     return pVal->z;
1337   }else{
1338     return 0;
1339   }
1340 }
1341
1342 /* This function is only available internally, it is not part of the
1343 ** external API. It works in a similar way to sqlite3_value_text(),
1344 ** except the data returned is in the encoding specified by the second
1345 ** parameter, which must be one of SQLITE_UTF16BE, SQLITE_UTF16LE or
1346 ** SQLITE_UTF8.
1347 **
1348 ** (2006-02-16:)  The enc value can be or-ed with SQLITE_UTF16_ALIGNED.
1349 ** If that is the case, then the result must be aligned on an even byte
1350 ** boundary.
1351 */
1352 const void *sqlite3ValueText(sqlite3_value* pVal, u8 enc){
1353   if( !pVal ) return 0;
1354   assert( pVal->db==0 || sqlite3_mutex_held(pVal->db->mutex) );
1355   assert( (enc&3)==(enc&~SQLITE_UTF16_ALIGNED) );
1356   assert( !sqlite3VdbeMemIsRowSet(pVal) );
1357   if( (pVal->flags&(MEM_Str|MEM_Term))==(MEM_Str|MEM_Term) && pVal->enc==enc ){
1358     assert( sqlite3VdbeMemValidStrRep(pVal) );
1359     return pVal->z;
1360   }
1361   if( pVal->flags&MEM_Null ){
1362     return 0;
1363   }
1364   return valueToText(pVal, enc);
1365 }
1366
1367 /*
1368 ** Create a new sqlite3_value object.
1369 */
1370 sqlite3_value *sqlite3ValueNew(sqlite3 *db){
1371   Mem *p = sqlite3DbMallocZero(db, sizeof(*p));
1372   if( p ){
1373     p->flags = MEM_Null;
1374     p->db = db;
1375   }
1376   return p;
1377 }
1378
1379 /*
1380 ** Context object passed by sqlite3Stat4ProbeSetValue() through to
1381 ** valueNew(). See comments above valueNew() for details.
1382 */
1383 struct ValueNewStat4Ctx {
1384   Parse *pParse;
1385   Index *pIdx;
1386   UnpackedRecord **ppRec;
1387   int iVal;
1388 };
1389
1390 /*
1391 ** Allocate and return a pointer to a new sqlite3_value object. If
1392 ** the second argument to this function is NULL, the object is allocated
1393 ** by calling sqlite3ValueNew().
1394 **
1395 ** Otherwise, if the second argument is non-zero, then this function is
1396 ** being called indirectly by sqlite3Stat4ProbeSetValue(). If it has not
1397 ** already been allocated, allocate the UnpackedRecord structure that
1398 ** that function will return to its caller here. Then return a pointer to
1399 ** an sqlite3_value within the UnpackedRecord.a[] array.
1400 */
1401 static sqlite3_value *valueNew(sqlite3 *db, struct ValueNewStat4Ctx *p){
1402 #ifdef SQLITE_ENABLE_STAT4
1403   if( p ){
1404     UnpackedRecord *pRec = p->ppRec[0];
1405
1406     if( pRec==0 ){
1407       Index *pIdx = p->pIdx;      /* Index being probed */
1408       int nByte;                  /* Bytes of space to allocate */
1409       int i;                      /* Counter variable */
1410       int nCol = pIdx->nColumn;   /* Number of index columns including rowid */
1411
1412       nByte = sizeof(Mem) * nCol + ROUND8(sizeof(UnpackedRecord));
1413       pRec = (UnpackedRecord*)sqlite3DbMallocZero(db, nByte);
1414       if( pRec ){
1415         pRec->pKeyInfo = sqlite3KeyInfoOfIndex(p->pParse, pIdx);
1416         if( pRec->pKeyInfo ){
1417           assert( pRec->pKeyInfo->nAllField==nCol );
1418           assert( pRec->pKeyInfo->enc==ENC(db) );
1419           pRec->aMem = (Mem *)((u8*)pRec + ROUND8(sizeof(UnpackedRecord)));
1420           for(i=0; i<nCol; i++){
1421             pRec->aMem[i].flags = MEM_Null;
1422             pRec->aMem[i].db = db;
1423           }
1424         }else{
1425           sqlite3DbFreeNN(db, pRec);
1426           pRec = 0;
1427         }
1428       }
1429       if( pRec==0 ) return 0;
1430       p->ppRec[0] = pRec;
1431     }
1432
1433     pRec->nField = p->iVal+1;
1434     return &pRec->aMem[p->iVal];
1435   }
1436 #else
1437   UNUSED_PARAMETER(p);
1438 #endif /* defined(SQLITE_ENABLE_STAT4) */
1439   return sqlite3ValueNew(db);
1440 }
1441
1442 /*
1443 ** The expression object indicated by the second argument is guaranteed
1444 ** to be a scalar SQL function. If
1445 **
1446 **   * all function arguments are SQL literals,
1447 **   * one of the SQLITE_FUNC_CONSTANT or _SLOCHNG function flags is set, and
1448 **   * the SQLITE_FUNC_NEEDCOLL function flag is not set,
1449 **
1450 ** then this routine attempts to invoke the SQL function. Assuming no
1451 ** error occurs, output parameter (*ppVal) is set to point to a value
1452 ** object containing the result before returning SQLITE_OK.
1453 **
1454 ** Affinity aff is applied to the result of the function before returning.
1455 ** If the result is a text value, the sqlite3_value object uses encoding
1456 ** enc.
1457 **
1458 ** If the conditions above are not met, this function returns SQLITE_OK
1459 ** and sets (*ppVal) to NULL. Or, if an error occurs, (*ppVal) is set to
1460 ** NULL and an SQLite error code returned.
1461 */
1462 #ifdef SQLITE_ENABLE_STAT4
1463 static int valueFromFunction(
1464   sqlite3 *db,                    /* The database connection */
1465   const Expr *p,                  /* The expression to evaluate */
1466   u8 enc,                         /* Encoding to use */
1467   u8 aff,                         /* Affinity to use */
1468   sqlite3_value **ppVal,          /* Write the new value here */
1469   struct ValueNewStat4Ctx *pCtx   /* Second argument for valueNew() */
1470 ){
1471   sqlite3_context ctx;            /* Context object for function invocation */
1472   sqlite3_value **apVal = 0;      /* Function arguments */
1473   int nVal = 0;                   /* Size of apVal[] array */
1474   FuncDef *pFunc = 0;             /* Function definition */
1475   sqlite3_value *pVal = 0;        /* New value */
1476   int rc = SQLITE_OK;             /* Return code */
1477   ExprList *pList = 0;            /* Function arguments */
1478   int i;                          /* Iterator variable */
1479
1480   assert( pCtx!=0 );
1481   assert( (p->flags & EP_TokenOnly)==0 );
1482   assert( ExprUseXList(p) );
1483   pList = p->x.pList;
1484   if( pList ) nVal = pList->nExpr;
1485   assert( !ExprHasProperty(p, EP_IntValue) );
1486   pFunc = sqlite3FindFunction(db, p->u.zToken, nVal, enc, 0);
1487 #ifdef SQLITE_ENABLE_UNKNOWN_SQL_FUNCTION
1488   if( pFunc==0 ) return SQLITE_OK;
1489 #endif
1490   assert( pFunc );
1491   if( (pFunc->funcFlags & (SQLITE_FUNC_CONSTANT|SQLITE_FUNC_SLOCHNG))==0
1492    || (pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL)
1493   ){
1494     return SQLITE_OK;
1495   }
1496
1497   if( pList ){
1498     apVal = (sqlite3_value**)sqlite3DbMallocZero(db, sizeof(apVal[0]) * nVal);
1499     if( apVal==0 ){
1500       rc = SQLITE_NOMEM_BKPT;
1501       goto value_from_function_out;
1502     }
1503     for(i=0; i<nVal; i++){
1504       rc = sqlite3ValueFromExpr(db, pList->a[i].pExpr, enc, aff, &apVal[i]);
1505       if( apVal[i]==0 || rc!=SQLITE_OK ) goto value_from_function_out;
1506     }
1507   }
1508
1509   pVal = valueNew(db, pCtx);
1510   if( pVal==0 ){
1511     rc = SQLITE_NOMEM_BKPT;
1512     goto value_from_function_out;
1513   }
1514
1515   memset(&ctx, 0, sizeof(ctx));
1516   ctx.pOut = pVal;
1517   ctx.pFunc = pFunc;
1518   ctx.enc = ENC(db);
1519   pFunc->xSFunc(&ctx, nVal, apVal);
1520   if( ctx.isError ){
1521     rc = ctx.isError;
1522     sqlite3ErrorMsg(pCtx->pParse, "%s", sqlite3_value_text(pVal));
1523   }else{
1524     sqlite3ValueApplyAffinity(pVal, aff, SQLITE_UTF8);
1525     assert( rc==SQLITE_OK );
1526     rc = sqlite3VdbeChangeEncoding(pVal, enc);
1527     if( NEVER(rc==SQLITE_OK && sqlite3VdbeMemTooBig(pVal)) ){
1528       rc = SQLITE_TOOBIG;
1529       pCtx->pParse->nErr++;
1530     }
1531   }
1532
1533  value_from_function_out:
1534   if( rc!=SQLITE_OK ){
1535     pVal = 0;
1536     pCtx->pParse->rc = rc;
1537   }
1538   if( apVal ){
1539     for(i=0; i<nVal; i++){
1540       sqlite3ValueFree(apVal[i]);
1541     }
1542     sqlite3DbFreeNN(db, apVal);
1543   }
1544
1545   *ppVal = pVal;
1546   return rc;
1547 }
1548 #else
1549 # define valueFromFunction(a,b,c,d,e,f) SQLITE_OK
1550 #endif /* defined(SQLITE_ENABLE_STAT4) */
1551
1552 /*
1553 ** Extract a value from the supplied expression in the manner described
1554 ** above sqlite3ValueFromExpr(). Allocate the sqlite3_value object
1555 ** using valueNew().
1556 **
1557 ** If pCtx is NULL and an error occurs after the sqlite3_value object
1558 ** has been allocated, it is freed before returning. Or, if pCtx is not
1559 ** NULL, it is assumed that the caller will free any allocated object
1560 ** in all cases.
1561 */
1562 static int valueFromExpr(
1563   sqlite3 *db,                    /* The database connection */
1564   const Expr *pExpr,              /* The expression to evaluate */
1565   u8 enc,                         /* Encoding to use */
1566   u8 affinity,                    /* Affinity to use */
1567   sqlite3_value **ppVal,          /* Write the new value here */
1568   struct ValueNewStat4Ctx *pCtx   /* Second argument for valueNew() */
1569 ){
1570   int op;
1571   char *zVal = 0;
1572   sqlite3_value *pVal = 0;
1573   int negInt = 1;
1574   const char *zNeg = "";
1575   int rc = SQLITE_OK;
1576
1577   assert( pExpr!=0 );
1578   while( (op = pExpr->op)==TK_UPLUS || op==TK_SPAN ) pExpr = pExpr->pLeft;
1579   if( op==TK_REGISTER ) op = pExpr->op2;
1580
1581   /* Compressed expressions only appear when parsing the DEFAULT clause
1582   ** on a table column definition, and hence only when pCtx==0.  This
1583   ** check ensures that an EP_TokenOnly expression is never passed down
1584   ** into valueFromFunction(). */
1585   assert( (pExpr->flags & EP_TokenOnly)==0 || pCtx==0 );
1586
1587   if( op==TK_CAST ){
1588     u8 aff;
1589     assert( !ExprHasProperty(pExpr, EP_IntValue) );
1590     aff = sqlite3AffinityType(pExpr->u.zToken,0);
1591     rc = valueFromExpr(db, pExpr->pLeft, enc, aff, ppVal, pCtx);
1592     testcase( rc!=SQLITE_OK );
1593     if( *ppVal ){
1594 #ifdef SQLITE_ENABLE_STAT4
1595       rc = ExpandBlob(*ppVal);
1596 #else
1597       /* zero-blobs only come from functions, not literal values.  And
1598       ** functions are only processed under STAT4 */
1599       assert( (ppVal[0][0].flags & MEM_Zero)==0 );
1600 #endif
1601       sqlite3VdbeMemCast(*ppVal, aff, enc);
1602       sqlite3ValueApplyAffinity(*ppVal, affinity, enc);
1603     }
1604     return rc;
1605   }
1606
1607   /* Handle negative integers in a single step.  This is needed in the
1608   ** case when the value is -9223372036854775808.
1609   */
1610   if( op==TK_UMINUS
1611    && (pExpr->pLeft->op==TK_INTEGER || pExpr->pLeft->op==TK_FLOAT) ){
1612     pExpr = pExpr->pLeft;
1613     op = pExpr->op;
1614     negInt = -1;
1615     zNeg = "-";
1616   }
1617
1618   if( op==TK_STRING || op==TK_FLOAT || op==TK_INTEGER ){
1619     pVal = valueNew(db, pCtx);
1620     if( pVal==0 ) goto no_mem;
1621     if( ExprHasProperty(pExpr, EP_IntValue) ){
1622       sqlite3VdbeMemSetInt64(pVal, (i64)pExpr->u.iValue*negInt);
1623     }else{
1624       zVal = sqlite3MPrintf(db, "%s%s", zNeg, pExpr->u.zToken);
1625       if( zVal==0 ) goto no_mem;
1626       sqlite3ValueSetStr(pVal, -1, zVal, SQLITE_UTF8, SQLITE_DYNAMIC);
1627     }
1628     if( (op==TK_INTEGER || op==TK_FLOAT ) && affinity==SQLITE_AFF_BLOB ){
1629       sqlite3ValueApplyAffinity(pVal, SQLITE_AFF_NUMERIC, SQLITE_UTF8);
1630     }else{
1631       sqlite3ValueApplyAffinity(pVal, affinity, SQLITE_UTF8);
1632     }
1633     assert( (pVal->flags & MEM_IntReal)==0 );
1634     if( pVal->flags & (MEM_Int|MEM_IntReal|MEM_Real) ){
1635       testcase( pVal->flags & MEM_Int );
1636       testcase( pVal->flags & MEM_Real );
1637       pVal->flags &= ~MEM_Str;
1638     }
1639     if( enc!=SQLITE_UTF8 ){
1640       rc = sqlite3VdbeChangeEncoding(pVal, enc);
1641     }
1642   }else if( op==TK_UMINUS ) {
1643     /* This branch happens for multiple negative signs.  Ex: -(-5) */
1644     if( SQLITE_OK==valueFromExpr(db,pExpr->pLeft,enc,affinity,&pVal,pCtx)
1645      && pVal!=0
1646     ){
1647       sqlite3VdbeMemNumerify(pVal);
1648       if( pVal->flags & MEM_Real ){
1649         pVal->u.r = -pVal->u.r;
1650       }else if( pVal->u.i==SMALLEST_INT64 ){
1651 #ifndef SQLITE_OMIT_FLOATING_POINT
1652         pVal->u.r = -(double)SMALLEST_INT64;
1653 #else
1654         pVal->u.r = LARGEST_INT64;
1655 #endif
1656         MemSetTypeFlag(pVal, MEM_Real);
1657       }else{
1658         pVal->u.i = -pVal->u.i;
1659       }
1660       sqlite3ValueApplyAffinity(pVal, affinity, enc);
1661     }
1662   }else if( op==TK_NULL ){
1663     pVal = valueNew(db, pCtx);
1664     if( pVal==0 ) goto no_mem;
1665     sqlite3VdbeMemSetNull(pVal);
1666   }
1667 #ifndef SQLITE_OMIT_BLOB_LITERAL
1668   else if( op==TK_BLOB ){
1669     int nVal;
1670     assert( !ExprHasProperty(pExpr, EP_IntValue) );
1671     assert( pExpr->u.zToken[0]=='x' || pExpr->u.zToken[0]=='X' );
1672     assert( pExpr->u.zToken[1]=='\'' );
1673     pVal = valueNew(db, pCtx);
1674     if( !pVal ) goto no_mem;
1675     zVal = &pExpr->u.zToken[2];
1676     nVal = sqlite3Strlen30(zVal)-1;
1677     assert( zVal[nVal]=='\'' );
1678     sqlite3VdbeMemSetStr(pVal, sqlite3HexToBlob(db, zVal, nVal), nVal/2,
1679                          0, SQLITE_DYNAMIC);
1680   }
1681 #endif
1682 #ifdef SQLITE_ENABLE_STAT4
1683   else if( op==TK_FUNCTION && pCtx!=0 ){
1684     rc = valueFromFunction(db, pExpr, enc, affinity, &pVal, pCtx);
1685   }
1686 #endif
1687   else if( op==TK_TRUEFALSE ){
1688     assert( !ExprHasProperty(pExpr, EP_IntValue) );
1689     pVal = valueNew(db, pCtx);
1690     if( pVal ){
1691       pVal->flags = MEM_Int;
1692       pVal->u.i = pExpr->u.zToken[4]==0;
1693     }
1694   }
1695
1696   *ppVal = pVal;
1697   return rc;
1698
1699 no_mem:
1700 #ifdef SQLITE_ENABLE_STAT4
1701   if( pCtx==0 || NEVER(pCtx->pParse->nErr==0) )
1702 #endif
1703     sqlite3OomFault(db);
1704   sqlite3DbFree(db, zVal);
1705   assert( *ppVal==0 );
1706 #ifdef SQLITE_ENABLE_STAT4
1707   if( pCtx==0 ) sqlite3ValueFree(pVal);
1708 #else
1709   assert( pCtx==0 ); sqlite3ValueFree(pVal);
1710 #endif
1711   return SQLITE_NOMEM_BKPT;
1712 }
1713
1714 /*
1715 ** Create a new sqlite3_value object, containing the value of pExpr.
1716 **
1717 ** This only works for very simple expressions that consist of one constant
1718 ** token (i.e. "5", "5.1", "'a string'"). If the expression can
1719 ** be converted directly into a value, then the value is allocated and
1720 ** a pointer written to *ppVal. The caller is responsible for deallocating
1721 ** the value by passing it to sqlite3ValueFree() later on. If the expression
1722 ** cannot be converted to a value, then *ppVal is set to NULL.
1723 */
1724 int sqlite3ValueFromExpr(
1725   sqlite3 *db,              /* The database connection */
1726   const Expr *pExpr,        /* The expression to evaluate */
1727   u8 enc,                   /* Encoding to use */
1728   u8 affinity,              /* Affinity to use */
1729   sqlite3_value **ppVal     /* Write the new value here */
1730 ){
1731   return pExpr ? valueFromExpr(db, pExpr, enc, affinity, ppVal, 0) : 0;
1732 }
1733
1734 #ifdef SQLITE_ENABLE_STAT4
1735 /*
1736 ** Attempt to extract a value from pExpr and use it to construct *ppVal.
1737 **
1738 ** If pAlloc is not NULL, then an UnpackedRecord object is created for
1739 ** pAlloc if one does not exist and the new value is added to the
1740 ** UnpackedRecord object.
1741 **
1742 ** A value is extracted in the following cases:
1743 **
1744 **  * (pExpr==0). In this case the value is assumed to be an SQL NULL,
1745 **
1746 **  * The expression is a bound variable, and this is a reprepare, or
1747 **
1748 **  * The expression is a literal value.
1749 **
1750 ** On success, *ppVal is made to point to the extracted value.  The caller
1751 ** is responsible for ensuring that the value is eventually freed.
1752 */
1753 static int stat4ValueFromExpr(
1754   Parse *pParse,                  /* Parse context */
1755   Expr *pExpr,                    /* The expression to extract a value from */
1756   u8 affinity,                    /* Affinity to use */
1757   struct ValueNewStat4Ctx *pAlloc,/* How to allocate space.  Or NULL */
1758   sqlite3_value **ppVal           /* OUT: New value object (or NULL) */
1759 ){
1760   int rc = SQLITE_OK;
1761   sqlite3_value *pVal = 0;
1762   sqlite3 *db = pParse->db;
1763
1764   /* Skip over any TK_COLLATE nodes */
1765   pExpr = sqlite3ExprSkipCollate(pExpr);
1766
1767   assert( pExpr==0 || pExpr->op!=TK_REGISTER || pExpr->op2!=TK_VARIABLE );
1768   if( !pExpr ){
1769     pVal = valueNew(db, pAlloc);
1770     if( pVal ){
1771       sqlite3VdbeMemSetNull((Mem*)pVal);
1772     }
1773   }else if( pExpr->op==TK_VARIABLE && (db->flags & SQLITE_EnableQPSG)==0 ){
1774     Vdbe *v;
1775     int iBindVar = pExpr->iColumn;
1776     sqlite3VdbeSetVarmask(pParse->pVdbe, iBindVar);
1777     if( (v = pParse->pReprepare)!=0 ){
1778       pVal = valueNew(db, pAlloc);
1779       if( pVal ){
1780         rc = sqlite3VdbeMemCopy((Mem*)pVal, &v->aVar[iBindVar-1]);
1781         sqlite3ValueApplyAffinity(pVal, affinity, ENC(db));
1782         pVal->db = pParse->db;
1783       }
1784     }
1785   }else{
1786     rc = valueFromExpr(db, pExpr, ENC(db), affinity, &pVal, pAlloc);
1787   }
1788
1789   assert( pVal==0 || pVal->db==db );
1790   *ppVal = pVal;
1791   return rc;
1792 }
1793
1794 /*
1795 ** This function is used to allocate and populate UnpackedRecord
1796 ** structures intended to be compared against sample index keys stored
1797 ** in the sqlite_stat4 table.
1798 **
1799 ** A single call to this function populates zero or more fields of the
1800 ** record starting with field iVal (fields are numbered from left to
1801 ** right starting with 0). A single field is populated if:
1802 **
1803 **  * (pExpr==0). In this case the value is assumed to be an SQL NULL,
1804 **
1805 **  * The expression is a bound variable, and this is a reprepare, or
1806 **
1807 **  * The sqlite3ValueFromExpr() function is able to extract a value
1808 **    from the expression (i.e. the expression is a literal value).
1809 **
1810 ** Or, if pExpr is a TK_VECTOR, one field is populated for each of the
1811 ** vector components that match either of the two latter criteria listed
1812 ** above.
1813 **
1814 ** Before any value is appended to the record, the affinity of the
1815 ** corresponding column within index pIdx is applied to it. Before
1816 ** this function returns, output parameter *pnExtract is set to the
1817 ** number of values appended to the record.
1818 **
1819 ** When this function is called, *ppRec must either point to an object
1820 ** allocated by an earlier call to this function, or must be NULL. If it
1821 ** is NULL and a value can be successfully extracted, a new UnpackedRecord
1822 ** is allocated (and *ppRec set to point to it) before returning.
1823 **
1824 ** Unless an error is encountered, SQLITE_OK is returned. It is not an
1825 ** error if a value cannot be extracted from pExpr. If an error does
1826 ** occur, an SQLite error code is returned.
1827 */
1828 int sqlite3Stat4ProbeSetValue(
1829   Parse *pParse,                  /* Parse context */
1830   Index *pIdx,                    /* Index being probed */
1831   UnpackedRecord **ppRec,         /* IN/OUT: Probe record */
1832   Expr *pExpr,                    /* The expression to extract a value from */
1833   int nElem,                      /* Maximum number of values to append */
1834   int iVal,                       /* Array element to populate */
1835   int *pnExtract                  /* OUT: Values appended to the record */
1836 ){
1837   int rc = SQLITE_OK;
1838   int nExtract = 0;
1839
1840   if( pExpr==0 || pExpr->op!=TK_SELECT ){
1841     int i;
1842     struct ValueNewStat4Ctx alloc;
1843
1844     alloc.pParse = pParse;
1845     alloc.pIdx = pIdx;
1846     alloc.ppRec = ppRec;
1847
1848     for(i=0; i<nElem; i++){
1849       sqlite3_value *pVal = 0;
1850       Expr *pElem = (pExpr ? sqlite3VectorFieldSubexpr(pExpr, i) : 0);
1851       u8 aff = sqlite3IndexColumnAffinity(pParse->db, pIdx, iVal+i);
1852       alloc.iVal = iVal+i;
1853       rc = stat4ValueFromExpr(pParse, pElem, aff, &alloc, &pVal);
1854       if( !pVal ) break;
1855       nExtract++;
1856     }
1857   }
1858
1859   *pnExtract = nExtract;
1860   return rc;
1861 }
1862
1863 /*
1864 ** Attempt to extract a value from expression pExpr using the methods
1865 ** as described for sqlite3Stat4ProbeSetValue() above.
1866 **
1867 ** If successful, set *ppVal to point to a new value object and return
1868 ** SQLITE_OK. If no value can be extracted, but no other error occurs
1869 ** (e.g. OOM), return SQLITE_OK and set *ppVal to NULL. Or, if an error
1870 ** does occur, return an SQLite error code. The final value of *ppVal
1871 ** is undefined in this case.
1872 */
1873 int sqlite3Stat4ValueFromExpr(
1874   Parse *pParse,                  /* Parse context */
1875   Expr *pExpr,                    /* The expression to extract a value from */
1876   u8 affinity,                    /* Affinity to use */
1877   sqlite3_value **ppVal           /* OUT: New value object (or NULL) */
1878 ){
1879   return stat4ValueFromExpr(pParse, pExpr, affinity, 0, ppVal);
1880 }
1881
1882 /*
1883 ** Extract the iCol-th column from the nRec-byte record in pRec.  Write
1884 ** the column value into *ppVal.  If *ppVal is initially NULL then a new
1885 ** sqlite3_value object is allocated.
1886 **
1887 ** If *ppVal is initially NULL then the caller is responsible for
1888 ** ensuring that the value written into *ppVal is eventually freed.
1889 */
1890 int sqlite3Stat4Column(
1891   sqlite3 *db,                    /* Database handle */
1892   const void *pRec,               /* Pointer to buffer containing record */
1893   int nRec,                       /* Size of buffer pRec in bytes */
1894   int iCol,                       /* Column to extract */
1895   sqlite3_value **ppVal           /* OUT: Extracted value */
1896 ){
1897   u32 t = 0;                      /* a column type code */
1898   int nHdr;                       /* Size of the header in the record */
1899   int iHdr;                       /* Next unread header byte */
1900   int iField;                     /* Next unread data byte */
1901   int szField = 0;                /* Size of the current data field */
1902   int i;                          /* Column index */
1903   u8 *a = (u8*)pRec;              /* Typecast byte array */
1904   Mem *pMem = *ppVal;             /* Write result into this Mem object */
1905
1906   assert( iCol>0 );
1907   iHdr = getVarint32(a, nHdr);
1908   if( nHdr>nRec || iHdr>=nHdr ) return SQLITE_CORRUPT_BKPT;
1909   iField = nHdr;
1910   for(i=0; i<=iCol; i++){
1911     iHdr += getVarint32(&a[iHdr], t);
1912     testcase( iHdr==nHdr );
1913     testcase( iHdr==nHdr+1 );
1914     if( iHdr>nHdr ) return SQLITE_CORRUPT_BKPT;
1915     szField = sqlite3VdbeSerialTypeLen(t);
1916     iField += szField;
1917   }
1918   testcase( iField==nRec );
1919   testcase( iField==nRec+1 );
1920   if( iField>nRec ) return SQLITE_CORRUPT_BKPT;
1921   if( pMem==0 ){
1922     pMem = *ppVal = sqlite3ValueNew(db);
1923     if( pMem==0 ) return SQLITE_NOMEM_BKPT;
1924   }
1925   sqlite3VdbeSerialGet(&a[iField-szField], t, pMem);
1926   pMem->enc = ENC(db);
1927   return SQLITE_OK;
1928 }
1929
1930 /*
1931 ** Unless it is NULL, the argument must be an UnpackedRecord object returned
1932 ** by an earlier call to sqlite3Stat4ProbeSetValue(). This call deletes
1933 ** the object.
1934 */
1935 void sqlite3Stat4ProbeFree(UnpackedRecord *pRec){
1936   if( pRec ){
1937     int i;
1938     int nCol = pRec->pKeyInfo->nAllField;
1939     Mem *aMem = pRec->aMem;
1940     sqlite3 *db = aMem[0].db;
1941     for(i=0; i<nCol; i++){
1942       sqlite3VdbeMemRelease(&aMem[i]);
1943     }
1944     sqlite3KeyInfoUnref(pRec->pKeyInfo);
1945     sqlite3DbFreeNN(db, pRec);
1946   }
1947 }
1948 #endif /* ifdef SQLITE_ENABLE_STAT4 */
1949
1950 /*
1951 ** Change the string value of an sqlite3_value object
1952 */
1953 void sqlite3ValueSetStr(
1954   sqlite3_value *v,     /* Value to be set */
1955   int n,                /* Length of string z */
1956   const void *z,        /* Text of the new string */
1957   u8 enc,               /* Encoding to use */
1958   void (*xDel)(void*)   /* Destructor for the string */
1959 ){
1960   if( v ) sqlite3VdbeMemSetStr((Mem *)v, z, n, enc, xDel);
1961 }
1962
1963 /*
1964 ** Free an sqlite3_value object
1965 */
1966 void sqlite3ValueFree(sqlite3_value *v){
1967   if( !v ) return;
1968   sqlite3VdbeMemRelease((Mem *)v);
1969   sqlite3DbFreeNN(((Mem*)v)->db, v);
1970 }
1971
1972 /*
1973 ** The sqlite3ValueBytes() routine returns the number of bytes in the
1974 ** sqlite3_value object assuming that it uses the encoding "enc".
1975 ** The valueBytes() routine is a helper function.
1976 */
1977 static SQLITE_NOINLINE int valueBytes(sqlite3_value *pVal, u8 enc){
1978   return valueToText(pVal, enc)!=0 ? pVal->n : 0;
1979 }
1980 int sqlite3ValueBytes(sqlite3_value *pVal, u8 enc){
1981   Mem *p = (Mem*)pVal;
1982   assert( (p->flags & MEM_Null)==0 || (p->flags & (MEM_Str|MEM_Blob))==0 );
1983   if( (p->flags & MEM_Str)!=0 && pVal->enc==enc ){
1984     return p->n;
1985   }
1986   if( (p->flags & MEM_Str)!=0 && enc!=SQLITE_UTF8 && pVal->enc!=SQLITE_UTF8 ){
1987     return p->n;
1988   }
1989   if( (p->flags & MEM_Blob)!=0 ){
1990     if( p->flags & MEM_Zero ){
1991       return p->n + p->u.nZero;
1992     }else{
1993       return p->n;
1994     }
1995   }
1996   if( p->flags & MEM_Null ) return 0;
1997   return valueBytes(pVal, enc);
1998 }