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Overview
| Comment: | Faster and smaller implementation of sqlite3AtoF() based on a suggestion from Cezary H. Noweta. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
fd2e0e7a770c2ce9355068aad1024c3d |
| User & Date: | drh 2017-12-26 14:46:20.800 |
Context
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2017-12-27
| ||
| 18:19 | Enhance the Lemon parser generator so that it creates a faster parser at the cost of slightly larger parser tables. Add the ability to measure coverage of the generated state machine when compiling with the -DYYCONVERGE option. In SQLite, add the SQLITE_TESTCTRL_PARSER_COVERAGE test-control to query the new parser coverage feature. (check-in: 1b22b42e59 user: drh tags: trunk) | |
|
2017-12-26
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| 18:14 | Merge bug fixes from trunk. (check-in: d76e12066f user: drh tags: lemon-improvements) | |
| 14:46 | Faster and smaller implementation of sqlite3AtoF() based on a suggestion from Cezary H. Noweta. (check-in: fd2e0e7a77 user: drh tags: trunk) | |
| 14:32 | Fix crashes that could occur if SQL NULL values were passed to the built-in FTS5 snippet function. Edit: breaks amalgamation builds. (check-in: 6a790b67a0 user: dan tags: trunk) | |
Changes
Changes to src/util.c.
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return 1;
}
a = (unsigned char *)zLeft;
b = (unsigned char *)zRight;
while( N-- > 0 && *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
return N<0 ? 0 : UpperToLower[*a] - UpperToLower[*b];
}
/*
** The string z[] is an text representation of a real number.
** Convert this string to a double and write it into *pResult.
**
** The string z[] is length bytes in length (bytes, not characters) and
** uses the encoding enc. The string is not necessarily zero-terminated.
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return 1;
}
a = (unsigned char *)zLeft;
b = (unsigned char *)zRight;
while( N-- > 0 && *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
return N<0 ? 0 : UpperToLower[*a] - UpperToLower[*b];
}
/*
** Compute 10 to the E-th power. Examples: E==1 results in 10.
** E==2 results in 100. E==50 results in 1.0e50.
**
** This routine only works for values of E between 1 and 341.
*/
static LONGDOUBLE_TYPE sqlite3Pow10(int E){
LONGDOUBLE_TYPE x = 10.0;
LONGDOUBLE_TYPE r = 1.0;
while(1){
if( E & 1 ) r *= x;
E >>= 1;
if( E==0 ) break;
x *= x;
}
return r;
}
/*
** The string z[] is an text representation of a real number.
** Convert this string to a double and write it into *pResult.
**
** The string z[] is length bytes in length (bytes, not characters) and
** uses the encoding enc. The string is not necessarily zero-terminated.
|
| ︙ | ︙ | |||
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/* adjust the sign of significand */
s = sign<0 ? -s : s;
if( e==0 ){ /*OPTIMIZATION-IF-TRUE*/
result = (double)s;
}else{
| < | < < | < | 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 |
/* adjust the sign of significand */
s = sign<0 ? -s : s;
if( e==0 ){ /*OPTIMIZATION-IF-TRUE*/
result = (double)s;
}else{
/* attempt to handle extremely small/large numbers better */
if( e>307 ){ /*OPTIMIZATION-IF-TRUE*/
if( e<342 ){ /*OPTIMIZATION-IF-TRUE*/
LONGDOUBLE_TYPE scale = sqlite3Pow10(e-308);
if( esign<0 ){
result = s / scale;
result /= 1.0e+308;
}else{
result = s * scale;
result *= 1.0e+308;
}
}else{ assert( e>=342 );
if( esign<0 ){
result = 0.0*s;
}else{
#ifdef INFINITY
result = INFINITY*s;
#else
result = 1e308*1e308*s; /* Infinity */
#endif
}
}
}else{
LONGDOUBLE_TYPE scale = sqlite3Pow10(e);
if( esign<0 ){
result = s / scale;
}else{
result = s * scale;
}
}
}
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