1 /* 2 ** 2001 September 15 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 ** Utility functions used throughout sqlite. 13 ** 14 ** This file contains functions for allocating memory, comparing 15 ** strings, and stuff like that. 16 ** 17 ** $Id: util.c,v 1.211 2007/08/21 19:33:57 drh Exp $ 18 */ 19 #include "sqliteInt.h" 20 #include <stdarg.h> 21 #include <ctype.h> 22 23 24 /* 25 ** Set the most recent error code and error string for the sqlite 26 ** handle "db". The error code is set to "err_code". 27 ** 28 ** If it is not NULL, string zFormat specifies the format of the 29 ** error string in the style of the printf functions: The following 30 ** format characters are allowed: 31 ** 32 ** %s Insert a string 33 ** %z A string that should be freed after use 34 ** %d Insert an integer 35 ** %T Insert a token 36 ** %S Insert the first element of a SrcList 37 ** 38 ** zFormat and any string tokens that follow it are assumed to be 39 ** encoded in UTF-8. 40 ** 41 ** To clear the most recent error for sqlite handle "db", sqlite3Error 42 ** should be called with err_code set to SQLITE_OK and zFormat set 43 ** to NULL. 44 */ 45 void sqlite3Error(sqlite3 *db, int err_code, const char *zFormat, ...){ 46 if( db && (db->pErr || (db->pErr = sqlite3ValueNew(db))!=0) ){ 47 db->errCode = err_code; 48 if( zFormat ){ 49 char *z; 50 va_list ap; 51 va_start(ap, zFormat); 52 z = sqlite3VMPrintf(db, zFormat, ap); 53 va_end(ap); 54 sqlite3ValueSetStr(db->pErr, -1, z, SQLITE_UTF8, sqlite3_free); 55 }else{ 56 sqlite3ValueSetStr(db->pErr, 0, 0, SQLITE_UTF8, SQLITE_STATIC); 57 } 58 } 59 } 60 61 /* 62 ** Add an error message to pParse->zErrMsg and increment pParse->nErr. 63 ** The following formatting characters are allowed: 64 ** 65 ** %s Insert a string 66 ** %z A string that should be freed after use 67 ** %d Insert an integer 68 ** %T Insert a token 69 ** %S Insert the first element of a SrcList 70 ** 71 ** This function should be used to report any error that occurs whilst 72 ** compiling an SQL statement (i.e. within sqlite3_prepare()). The 73 ** last thing the sqlite3_prepare() function does is copy the error 74 ** stored by this function into the database handle using sqlite3Error(). 75 ** Function sqlite3Error() should be used during statement execution 76 ** (sqlite3_step() etc.). 77 */ 78 void sqlite3ErrorMsg(Parse *pParse, const char *zFormat, ...){ 79 va_list ap; 80 pParse->nErr++; 81 sqlite3_free(pParse->zErrMsg); 82 va_start(ap, zFormat); 83 pParse->zErrMsg = sqlite3VMPrintf(pParse->db, zFormat, ap); 84 va_end(ap); 85 if( pParse->rc==SQLITE_OK ){ 86 pParse->rc = SQLITE_ERROR; 87 } 88 } 89 90 /* 91 ** Clear the error message in pParse, if any 92 */ 93 void sqlite3ErrorClear(Parse *pParse){ 94 sqlite3_free(pParse->zErrMsg); 95 pParse->zErrMsg = 0; 96 pParse->nErr = 0; 97 } 98 99 /* 100 ** Convert an SQL-style quoted string into a normal string by removing 101 ** the quote characters. The conversion is done in-place. If the 102 ** input does not begin with a quote character, then this routine 103 ** is a no-op. 104 ** 105 ** 2002-Feb-14: This routine is extended to remove MS-Access style 106 ** brackets from around identifers. For example: "[a-b-c]" becomes 107 ** "a-b-c". 108 */ 109 void sqlite3Dequote(char *z){ 110 int quote; 111 int i, j; 112 if( z==0 ) return; 113 quote = z[0]; 114 switch( quote ){ 115 case '\'': break; 116 case '"': break; 117 case '`': break; /* For MySQL compatibility */ 118 case '[': quote = ']'; break; /* For MS SqlServer compatibility */ 119 default: return; 120 } 121 for(i=1, j=0; z[i]; i++){ 122 if( z[i]==quote ){ 123 if( z[i+1]==quote ){ 124 z[j++] = quote; 125 i++; 126 }else{ 127 z[j++] = 0; 128 break; 129 } 130 }else{ 131 z[j++] = z[i]; 132 } 133 } 134 } 135 136 /* An array to map all upper-case characters into their corresponding 137 ** lower-case character. 138 */ 139 const unsigned char sqlite3UpperToLower[] = { 140 #ifdef SQLITE_ASCII 141 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 142 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 143 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 144 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 97, 98, 99,100,101,102,103, 145 104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121, 146 122, 91, 92, 93, 94, 95, 96, 97, 98, 99,100,101,102,103,104,105,106,107, 147 108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125, 148 126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143, 149 144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161, 150 162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179, 151 180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197, 152 198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215, 153 216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233, 154 234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251, 155 252,253,254,255 156 #endif 157 #ifdef SQLITE_EBCDIC 158 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, /* 0x */ 159 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, /* 1x */ 160 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, /* 2x */ 161 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, /* 3x */ 162 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, /* 4x */ 163 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, /* 5x */ 164 96, 97, 66, 67, 68, 69, 70, 71, 72, 73,106,107,108,109,110,111, /* 6x */ 165 112, 81, 82, 83, 84, 85, 86, 87, 88, 89,122,123,124,125,126,127, /* 7x */ 166 128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143, /* 8x */ 167 144,145,146,147,148,149,150,151,152,153,154,155,156,157,156,159, /* 9x */ 168 160,161,162,163,164,165,166,167,168,169,170,171,140,141,142,175, /* Ax */ 169 176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191, /* Bx */ 170 192,129,130,131,132,133,134,135,136,137,202,203,204,205,206,207, /* Cx */ 171 208,145,146,147,148,149,150,151,152,153,218,219,220,221,222,223, /* Dx */ 172 224,225,162,163,164,165,166,167,168,169,232,203,204,205,206,207, /* Ex */ 173 239,240,241,242,243,244,245,246,247,248,249,219,220,221,222,255, /* Fx */ 174 #endif 175 }; 176 #define UpperToLower sqlite3UpperToLower 177 178 /* 179 ** Some systems have stricmp(). Others have strcasecmp(). Because 180 ** there is no consistency, we will define our own. 181 */ 182 int sqlite3StrICmp(const char *zLeft, const char *zRight){ 183 register unsigned char *a, *b; 184 a = (unsigned char *)zLeft; 185 b = (unsigned char *)zRight; 186 while( *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; } 187 return UpperToLower[*a] - UpperToLower[*b]; 188 } 189 int sqlite3StrNICmp(const char *zLeft, const char *zRight, int N){ 190 register unsigned char *a, *b; 191 a = (unsigned char *)zLeft; 192 b = (unsigned char *)zRight; 193 while( N-- > 0 && *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; } 194 return N<0 ? 0 : UpperToLower[*a] - UpperToLower[*b]; 195 } 196 197 /* 198 ** Return TRUE if z is a pure numeric string. Return FALSE if the 199 ** string contains any character which is not part of a number. If 200 ** the string is numeric and contains the '.' character, set *realnum 201 ** to TRUE (otherwise FALSE). 202 ** 203 ** An empty string is considered non-numeric. 204 */ 205 int sqlite3IsNumber(const char *z, int *realnum, u8 enc){ 206 int incr = (enc==SQLITE_UTF8?1:2); 207 if( enc==SQLITE_UTF16BE ) z++; 208 if( *z=='-' || *z=='+' ) z += incr; 209 if( !isdigit(*(u8*)z) ){ 210 return 0; 211 } 212 z += incr; 213 if( realnum ) *realnum = 0; 214 while( isdigit(*(u8*)z) ){ z += incr; } 215 if( *z=='.' ){ 216 z += incr; 217 if( !isdigit(*(u8*)z) ) return 0; 218 while( isdigit(*(u8*)z) ){ z += incr; } 219 if( realnum ) *realnum = 1; 220 } 221 if( *z=='e' || *z=='E' ){ 222 z += incr; 223 if( *z=='+' || *z=='-' ) z += incr; 224 if( !isdigit(*(u8*)z) ) return 0; 225 while( isdigit(*(u8*)z) ){ z += incr; } 226 if( realnum ) *realnum = 1; 227 } 228 return *z==0; 229 } 230 231 /* 232 ** The string z[] is an ascii representation of a real number. 233 ** Convert this string to a double. 234 ** 235 ** This routine assumes that z[] really is a valid number. If it 236 ** is not, the result is undefined. 237 ** 238 ** This routine is used instead of the library atof() function because 239 ** the library atof() might want to use "," as the decimal point instead 240 ** of "." depending on how locale is set. But that would cause problems 241 ** for SQL. So this routine always uses "." regardless of locale. 242 */ 243 int sqlite3AtoF(const char *z, double *pResult){ 244 #ifndef SQLITE_OMIT_FLOATING_POINT 245 int sign = 1; 246 const char *zBegin = z; 247 LONGDOUBLE_TYPE v1 = 0.0; 248 while( isspace(*(u8*)z) ) z++; 249 if( *z=='-' ){ 250 sign = -1; 251 z++; 252 }else if( *z=='+' ){ 253 z++; 254 } 255 while( isdigit(*(u8*)z) ){ 256 v1 = v1*10.0 + (*z - '0'); 257 z++; 258 } 259 if( *z=='.' ){ 260 LONGDOUBLE_TYPE divisor = 1.0; 261 z++; 262 while( isdigit(*(u8*)z) ){ 263 v1 = v1*10.0 + (*z - '0'); 264 divisor *= 10.0; 265 z++; 266 } 267 v1 /= divisor; 268 } 269 if( *z=='e' || *z=='E' ){ 270 int esign = 1; 271 int eval = 0; 272 LONGDOUBLE_TYPE scale = 1.0; 273 z++; 274 if( *z=='-' ){ 275 esign = -1; 276 z++; 277 }else if( *z=='+' ){ 278 z++; 279 } 280 while( isdigit(*(u8*)z) ){ 281 eval = eval*10 + *z - '0'; 282 z++; 283 } 284 while( eval>=64 ){ scale *= 1.0e+64; eval -= 64; } 285 while( eval>=16 ){ scale *= 1.0e+16; eval -= 16; } 286 while( eval>=4 ){ scale *= 1.0e+4; eval -= 4; } 287 while( eval>=1 ){ scale *= 1.0e+1; eval -= 1; } 288 if( esign<0 ){ 289 v1 /= scale; 290 }else{ 291 v1 *= scale; 292 } 293 } 294 *pResult = sign<0 ? -v1 : v1; 295 return z - zBegin; 296 #else 297 return sqlite3Atoi64(z, pResult); 298 #endif /* SQLITE_OMIT_FLOATING_POINT */ 299 } 300 301 /* 302 ** Compare the 19-character string zNum against the text representation 303 ** value 2^63: 9223372036854775808. Return negative, zero, or positive 304 ** if zNum is less than, equal to, or greater than the string. 305 ** 306 ** Unlike memcmp() this routine is guaranteed to return the difference 307 ** in the values of the last digit if the only difference is in the 308 ** last digit. So, for example, 309 ** 310 ** compare2pow63("9223372036854775800") 311 ** 312 ** will return -8. 313 */ 314 static int compare2pow63(const char *zNum){ 315 int c; 316 c = memcmp(zNum,"922337203685477580",18); 317 if( c==0 ){ 318 c = zNum[18] - '8'; 319 } 320 return c; 321 } 322 323 324 /* 325 ** Return TRUE if zNum is a 64-bit signed integer and write 326 ** the value of the integer into *pNum. If zNum is not an integer 327 ** or is an integer that is too large to be expressed with 64 bits, 328 ** then return false. 329 ** 330 ** When this routine was originally written it dealt with only 331 ** 32-bit numbers. At that time, it was much faster than the 332 ** atoi() library routine in RedHat 7.2. 333 */ 334 int sqlite3Atoi64(const char *zNum, i64 *pNum){ 335 i64 v = 0; 336 int neg; 337 int i, c; 338 while( isspace(*(u8*)zNum) ) zNum++; 339 if( *zNum=='-' ){ 340 neg = 1; 341 zNum++; 342 }else if( *zNum=='+' ){ 343 neg = 0; 344 zNum++; 345 }else{ 346 neg = 0; 347 } 348 while( zNum[0]=='0' ){ zNum++; } /* Skip over leading zeros. Ticket #2454 */ 349 for(i=0; (c=zNum[i])>='0' && c<='9'; i++){ 350 v = v*10 + c - '0'; 351 } 352 *pNum = neg ? -v : v; 353 if( c!=0 || i==0 || i>19 ){ 354 /* zNum is empty or contains non-numeric text or is longer 355 ** than 19 digits (thus guaranting that it is too large) */ 356 return 0; 357 }else if( i<19 ){ 358 /* Less than 19 digits, so we know that it fits in 64 bits */ 359 return 1; 360 }else{ 361 /* 19-digit numbers must be no larger than 9223372036854775807 if positive 362 ** or 9223372036854775808 if negative. Note that 9223372036854665808 363 ** is 2^63. */ 364 return compare2pow63(zNum)<neg; 365 } 366 } 367 368 /* 369 ** The string zNum represents an integer. There might be some other 370 ** information following the integer too, but that part is ignored. 371 ** If the integer that the prefix of zNum represents will fit in a 372 ** 64-bit signed integer, return TRUE. Otherwise return FALSE. 373 ** 374 ** This routine returns FALSE for the string -9223372036854775808 even that 375 ** that number will, in theory fit in a 64-bit integer. Positive 376 ** 9223373036854775808 will not fit in 64 bits. So it seems safer to return 377 ** false. 378 */ 379 int sqlite3FitsIn64Bits(const char *zNum){ 380 int i, c; 381 int neg = 0; 382 if( *zNum=='-' ){ 383 neg = 1; 384 zNum++; 385 }else if( *zNum=='+' ){ 386 zNum++; 387 } 388 while( *zNum=='0' ){ 389 zNum++; /* Skip leading zeros. Ticket #2454 */ 390 } 391 for(i=0; (c=zNum[i])>='0' && c<='9'; i++){} 392 if( i<19 ){ 393 /* Guaranteed to fit if less than 19 digits */ 394 return 1; 395 }else if( i>19 ){ 396 /* Guaranteed to be too big if greater than 19 digits */ 397 return 0; 398 }else{ 399 /* Compare against 2^63. */ 400 return compare2pow63(zNum)<neg; 401 } 402 } 403 404 /* 405 ** If zNum represents an integer that will fit in 32-bits, then set 406 ** *pValue to that integer and return true. Otherwise return false. 407 ** 408 ** Any non-numeric characters that following zNum are ignored. 409 ** This is different from sqlite3Atoi64() which requires the 410 ** input number to be zero-terminated. 411 */ 412 int sqlite3GetInt32(const char *zNum, int *pValue){ 413 sqlite_int64 v = 0; 414 int i, c; 415 int neg = 0; 416 if( zNum[0]=='-' ){ 417 neg = 1; 418 zNum++; 419 }else if( zNum[0]=='+' ){ 420 zNum++; 421 } 422 while( zNum[0]=='0' ) zNum++; 423 for(i=0; i<10 && (c = zNum[i] - '0')>=0 && c<=9; i++){ 424 v = v*10 + c; 425 } 426 if( i>9 ){ 427 return 0; 428 } 429 if( v-neg>2147483647 ){ 430 return 0; 431 } 432 if( neg ){ 433 v = -v; 434 } 435 *pValue = (int)v; 436 return 1; 437 } 438 439 /* 440 ** Check to make sure we have a valid db pointer. This test is not 441 ** foolproof but it does provide some measure of protection against 442 ** misuse of the interface such as passing in db pointers that are 443 ** NULL or which have been previously closed. If this routine returns 444 ** TRUE it means that the db pointer is invalid and should not be 445 ** dereferenced for any reason. The calling function should invoke 446 ** SQLITE_MISUSE immediately. 447 */ 448 int sqlite3SafetyCheck(sqlite3 *db){ 449 int magic; 450 if( db==0 ) return 1; 451 magic = db->magic; 452 if( magic!=SQLITE_MAGIC_CLOSED && 453 magic!=SQLITE_MAGIC_OPEN && 454 magic!=SQLITE_MAGIC_BUSY ) return 1; 455 return 0; 456 } 457 458 /* 459 ** The variable-length integer encoding is as follows: 460 ** 461 ** KEY: 462 ** A = 0xxxxxxx 7 bits of data and one flag bit 463 ** B = 1xxxxxxx 7 bits of data and one flag bit 464 ** C = xxxxxxxx 8 bits of data 465 ** 466 ** 7 bits - A 467 ** 14 bits - BA 468 ** 21 bits - BBA 469 ** 28 bits - BBBA 470 ** 35 bits - BBBBA 471 ** 42 bits - BBBBBA 472 ** 49 bits - BBBBBBA 473 ** 56 bits - BBBBBBBA 474 ** 64 bits - BBBBBBBBC 475 */ 476 477 /* 478 ** Write a 64-bit variable-length integer to memory starting at p[0]. 479 ** The length of data write will be between 1 and 9 bytes. The number 480 ** of bytes written is returned. 481 ** 482 ** A variable-length integer consists of the lower 7 bits of each byte 483 ** for all bytes that have the 8th bit set and one byte with the 8th 484 ** bit clear. Except, if we get to the 9th byte, it stores the full 485 ** 8 bits and is the last byte. 486 */ 487 int sqlite3PutVarint(unsigned char *p, u64 v){ 488 int i, j, n; 489 u8 buf[10]; 490 if( v & (((u64)0xff000000)<<32) ){ 491 p[8] = v; 492 v >>= 8; 493 for(i=7; i>=0; i--){ 494 p[i] = (v & 0x7f) | 0x80; 495 v >>= 7; 496 } 497 return 9; 498 } 499 n = 0; 500 do{ 501 buf[n++] = (v & 0x7f) | 0x80; 502 v >>= 7; 503 }while( v!=0 ); 504 buf[0] &= 0x7f; 505 assert( n<=9 ); 506 for(i=0, j=n-1; j>=0; j--, i++){ 507 p[i] = buf[j]; 508 } 509 return n; 510 } 511 512 /* 513 ** Read a 64-bit variable-length integer from memory starting at p[0]. 514 ** Return the number of bytes read. The value is stored in *v. 515 */ 516 int sqlite3GetVarint(const unsigned char *p, u64 *v){ 517 u32 x; 518 u64 x64; 519 int n; 520 unsigned char c; 521 if( ((c = p[0]) & 0x80)==0 ){ 522 *v = c; 523 return 1; 524 } 525 x = c & 0x7f; 526 if( ((c = p[1]) & 0x80)==0 ){ 527 *v = (x<<7) | c; 528 return 2; 529 } 530 x = (x<<7) | (c&0x7f); 531 if( ((c = p[2]) & 0x80)==0 ){ 532 *v = (x<<7) | c; 533 return 3; 534 } 535 x = (x<<7) | (c&0x7f); 536 if( ((c = p[3]) & 0x80)==0 ){ 537 *v = (x<<7) | c; 538 return 4; 539 } 540 x64 = (x<<7) | (c&0x7f); 541 n = 4; 542 do{ 543 c = p[n++]; 544 if( n==9 ){ 545 x64 = (x64<<8) | c; 546 break; 547 } 548 x64 = (x64<<7) | (c&0x7f); 549 }while( (c & 0x80)!=0 ); 550 *v = x64; 551 return n; 552 } 553 554 /* 555 ** Read a 32-bit variable-length integer from memory starting at p[0]. 556 ** Return the number of bytes read. The value is stored in *v. 557 */ 558 int sqlite3GetVarint32(const unsigned char *p, u32 *v){ 559 u32 x; 560 int n; 561 unsigned char c; 562 if( ((signed char*)p)[0]>=0 ){ 563 *v = p[0]; 564 return 1; 565 } 566 x = p[0] & 0x7f; 567 if( ((signed char*)p)[1]>=0 ){ 568 *v = (x<<7) | p[1]; 569 return 2; 570 } 571 x = (x<<7) | (p[1] & 0x7f); 572 n = 2; 573 do{ 574 x = (x<<7) | ((c = p[n++])&0x7f); 575 }while( (c & 0x80)!=0 && n<9 ); 576 *v = x; 577 return n; 578 } 579 580 /* 581 ** Return the number of bytes that will be needed to store the given 582 ** 64-bit integer. 583 */ 584 int sqlite3VarintLen(u64 v){ 585 int i = 0; 586 do{ 587 i++; 588 v >>= 7; 589 }while( v!=0 && i<9 ); 590 return i; 591 } 592 593 594 /* 595 ** Read or write a four-byte big-endian integer value. 596 */ 597 u32 sqlite3Get4byte(const u8 *p){ 598 return (p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3]; 599 } 600 void sqlite3Put4byte(unsigned char *p, u32 v){ 601 p[0] = v>>24; 602 p[1] = v>>16; 603 p[2] = v>>8; 604 p[3] = v; 605 } 606 607 608 609 #if !defined(SQLITE_OMIT_BLOB_LITERAL) || defined(SQLITE_HAS_CODEC) \ 610 || defined(SQLITE_TEST) 611 /* 612 ** Translate a single byte of Hex into an integer. 613 */ 614 static int hexToInt(int h){ 615 if( h>='0' && h<='9' ){ 616 return h - '0'; 617 }else if( h>='a' && h<='f' ){ 618 return h - 'a' + 10; 619 }else{ 620 assert( h>='A' && h<='F' ); 621 return h - 'A' + 10; 622 } 623 } 624 #endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC || SQLITE_TEST */ 625 626 #if !defined(SQLITE_OMIT_BLOB_LITERAL) || defined(SQLITE_HAS_CODEC) 627 /* 628 ** Convert a BLOB literal of the form "x'hhhhhh'" into its binary 629 ** value. Return a pointer to its binary value. Space to hold the 630 ** binary value has been obtained from malloc and must be freed by 631 ** the calling routine. 632 */ 633 void *sqlite3HexToBlob(sqlite3 *db, const char *z){ 634 char *zBlob; 635 int i; 636 int n = strlen(z); 637 if( n%2 ) return 0; 638 639 zBlob = (char *)sqlite3DbMallocRaw(db, n/2); 640 if( zBlob ){ 641 for(i=0; i<n; i+=2){ 642 zBlob[i/2] = (hexToInt(z[i])<<4) | hexToInt(z[i+1]); 643 } 644 } 645 return zBlob; 646 } 647 #endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */ 648 649 650 /* 651 ** Change the sqlite.magic from SQLITE_MAGIC_OPEN to SQLITE_MAGIC_BUSY. 652 ** Return an error (non-zero) if the magic was not SQLITE_MAGIC_OPEN 653 ** when this routine is called. 654 ** 655 ** This routine is called when entering an SQLite API. The SQLITE_MAGIC_OPEN 656 ** value indicates that the database connection passed into the API is 657 ** open and is not being used by another thread. By changing the value 658 ** to SQLITE_MAGIC_BUSY we indicate that the connection is in use. 659 ** sqlite3SafetyOff() below will change the value back to SQLITE_MAGIC_OPEN 660 ** when the API exits. 661 ** 662 ** This routine is a attempt to detect if two threads use the 663 ** same sqlite* pointer at the same time. There is a race 664 ** condition so it is possible that the error is not detected. 665 ** But usually the problem will be seen. The result will be an 666 ** error which can be used to debug the application that is 667 ** using SQLite incorrectly. 668 ** 669 ** Ticket #202: If db->magic is not a valid open value, take care not 670 ** to modify the db structure at all. It could be that db is a stale 671 ** pointer. In other words, it could be that there has been a prior 672 ** call to sqlite3_close(db) and db has been deallocated. And we do 673 ** not want to write into deallocated memory. 674 */ 675 int sqlite3SafetyOn(sqlite3 *db){ 676 if( db->magic==SQLITE_MAGIC_OPEN ){ 677 db->magic = SQLITE_MAGIC_BUSY; 678 return 0; 679 }else if( db->magic==SQLITE_MAGIC_BUSY ){ 680 db->magic = SQLITE_MAGIC_ERROR; 681 db->u1.isInterrupted = 1; 682 } 683 return 1; 684 } 685 686 /* 687 ** Change the magic from SQLITE_MAGIC_BUSY to SQLITE_MAGIC_OPEN. 688 ** Return an error (non-zero) if the magic was not SQLITE_MAGIC_BUSY 689 ** when this routine is called. 690 */ 691 int sqlite3SafetyOff(sqlite3 *db){ 692 if( db->magic==SQLITE_MAGIC_BUSY ){ 693 db->magic = SQLITE_MAGIC_OPEN; 694 return 0; 695 }else { 696 db->magic = SQLITE_MAGIC_ERROR; 697 db->u1.isInterrupted = 1; 698 return 1; 699 } 700 } 701