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Overview
| Comment: | Performance enhancement in sqlite3AtoF(). About 8% faster. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
81721aa54587e20d031d528fb6b74d91 |
| User & Date: | drh 2019-05-25 18:17:53.260 |
Context
|
2019-05-27
| ||
| 00:29 | Improved rounding even on systems with an 8-byte "long double" type. (check-in: 15202aee15 user: drh tags: trunk) | |
|
2019-05-25
| ||
| 18:17 | Performance enhancement in sqlite3AtoF(). About 8% faster. (check-in: 81721aa545 user: drh tags: trunk) | |
| 17:41 | Use "long double" literals to initialize an array of "long double" objects. (check-in: 2e2ebad3ab user: drh tags: trunk) | |
Changes
Changes to src/util.c.
| ︙ | ︙ | |||
419 420 421 422 423 424 425 | int sign = 1; /* sign of significand */ i64 s = 0; /* significand */ int d = 0; /* adjust exponent for shifting decimal point */ int esign = 1; /* sign of exponent */ int e = 0; /* exponent */ int eValid = 1; /* True exponent is either not used or is well-formed */ double result; | | | 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 |
int sign = 1; /* sign of significand */
i64 s = 0; /* significand */
int d = 0; /* adjust exponent for shifting decimal point */
int esign = 1; /* sign of exponent */
int e = 0; /* exponent */
int eValid = 1; /* True exponent is either not used or is well-formed */
double result;
int nDigit = 0; /* Number of digits processed */
int nonNum = 0; /* True if input contains UTF16 with high byte non-zero */
assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
*pResult = 0.0; /* Default return value, in case of an error */
if( enc==SQLITE_UTF8 ){
incr = 1;
|
| ︙ | ︙ | |||
450 451 452 453 454 455 456 |
sign = -1;
z+=incr;
}else if( *z=='+' ){
z+=incr;
}
/* copy max significant digits to significand */
| | | < | | | | > > > | | 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 |
sign = -1;
z+=incr;
}else if( *z=='+' ){
z+=incr;
}
/* copy max significant digits to significand */
while( z<zEnd && sqlite3Isdigit(*z) ){
s = s*10 + (*z - '0');
z+=incr; nDigit++;
if( s>=((LARGEST_INT64-9)/10) ){
/* skip non-significant significand digits
** (increase exponent by d to shift decimal left) */
while( z<zEnd && sqlite3Isdigit(*z) ){ z+=incr; d++; }
}
}
if( z>=zEnd ) goto do_atof_calc;
/* if decimal point is present */
if( *z=='.' ){
z+=incr;
/* copy digits from after decimal to significand
** (decrease exponent by d to shift decimal right) */
while( z<zEnd && sqlite3Isdigit(*z) ){
if( s<((LARGEST_INT64-9)/10) ){
s = s*10 + (*z - '0');
d--;
nDigit++;
}
z+=incr;
}
}
if( z>=zEnd ) goto do_atof_calc;
/* if exponent is present */
if( *z=='e' || *z=='E' ){
z+=incr;
|
| ︙ | ︙ | |||
577 578 579 580 581 582 583 |
}
}
/* store the result */
*pResult = result;
/* return true if number and no extra non-whitespace chracters after */
| | | 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 |
}
}
/* store the result */
*pResult = result;
/* return true if number and no extra non-whitespace chracters after */
return z==zEnd && nDigit>0 && eValid && nonNum==0;
#else
return !sqlite3Atoi64(z, pResult, length, enc);
#endif /* SQLITE_OMIT_FLOATING_POINT */
}
/*
** Compare the 19-character string zNum against the text representation
|
| ︙ | ︙ |