database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-08-01 03:47:19 +03:00
Code Activity

Merge bk-internal.mysql.com:/home/bk/mysql-4.1-maint

Browse Source 
into  polly.local:/home/kaa/src/maint/m41-maint--07OGk
This commit is contained in:
unknown
2006-09-22 19:50:16 +04:00
parent c9983fcf0d e749f9eb67
commit 41c25e0185
3 changed files with 61 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
mysql-test/r/type_float.result
View File

@ -272,3 +272,10 @@ desc t3;
Field Type Null Key Default Extra
a double 0
drop table t1,t2,t3;
select 1e-308, 1.00000001e-300, 100000000e-300;
1e-308 1.00000001e-300 100000000e-300
0 1.00000001e-300 1e-292
select 10e307;
10e307
1e+308
End of 4.1 tests

11
mysql-test/t/type_float.test
View File

@ -179,4 +179,13 @@ show warnings;
desc t3;
drop table t1,t2,t3;
# End of 4.1 tests
#
# Bug #22129: A small double precision number becomes zero
#
# check if underflows are detected correctly
select 1e-308, 1.00000001e-300, 100000000e-300;
# check if overflows are detected correctly
select 10e307;
--echo End of 4.1 tests

69
strings/strtod.c
View File

@ -30,7 +30,8 @@
#include <m_ctype.h>
#define MAX_DBL_EXP 308
#define MAX_RESULT_FOR_MAX_EXP 1.79769313486232
#define MAX_RESULT_FOR_MAX_EXP 1.7976931348623157
#define MIN_RESULT_FOR_MIN_EXP 2.225073858507202
static double scaler10[] = {
1.0, 1e10, 1e20, 1e30, 1e40, 1e50, 1e60, 1e70, 1e80, 1e90
};
@ -57,10 +58,11 @@ double my_strtod(const char *str, char **end_ptr, int *error)
{
double result= 0.0;
uint negative= 0, ndigits, dec_digits= 0, neg_exp= 0;
int exp= 0, digits_after_dec_point= 0;
int exp= 0, digits_after_dec_point= 0, tmp_exp;
const char *old_str, *end= *end_ptr, *start_of_number;
char next_char;
my_bool overflow=0;
double scaler= 1.0;
*error= 0;
if (str >= end)
@ -91,6 +93,7 @@ double my_strtod(const char *str, char **end_ptr, int *error)
while ((next_char= *str) >= '0' && next_char <= '9')
{
result= result*10.0 + (next_char - '0');
scaler= scaler*10.0;
if (++str == end)
{
next_char= 0; /* Found end of string */
@ -114,6 +117,7 @@ double my_strtod(const char *str, char **end_ptr, int *error)
{
result= result*10.0 + (next_char - '0');
digits_after_dec_point++;
scaler= scaler*10.0;
if (++str == end)
{
next_char= 0;
@ -144,39 +148,54 @@ double my_strtod(const char *str, char **end_ptr, int *error)
} while (str < end && my_isdigit(&my_charset_latin1, *str));
}
}
if ((exp= (neg_exp ? exp + digits_after_dec_point :
exp - digits_after_dec_point)))
tmp_exp= neg_exp ? exp + digits_after_dec_point : exp - digits_after_dec_point;
if (tmp_exp)
{
double scaler;
int order;
/*
Check for underflow/overflow.
order is such an integer number that f = C * 10 ^ order,
where f is the resulting floating point number and 1 <= C < 10.
Here we compute the modulus
*/
order= exp + (neg_exp ? -1 : 1) * (ndigits - 1);
if (order < 0)
order= -order;
if (order >= MAX_DBL_EXP && result)
{
double c;
/* Compute modulus of C (see comment above) */
c= result / scaler * 10.0;
if (neg_exp)
{
if (order > MAX_DBL_EXP || c < MIN_RESULT_FOR_MIN_EXP)
{
result= 0.0;
goto done;
}
}
else
{
if (order > MAX_DBL_EXP || c > MAX_RESULT_FOR_MAX_EXP)
{
overflow= 1;
goto done;
}
}
}
exp= tmp_exp;
if (exp < 0)
{
exp= -exp;
neg_exp= 1; /* neg_exp was 0 before */
}
if (exp + ndigits >= MAX_DBL_EXP + 1 && result)
{
/*
This is not 100 % as we actually will give an owerflow for
17E307 but not for 1.7E308 but lets cut some corners to make life
simpler
*/
if (exp + ndigits > MAX_DBL_EXP + 1 ||
result >= MAX_RESULT_FOR_MAX_EXP)
{
if (neg_exp)
result= 0.0;
else
overflow= 1;
goto done;
}
}
scaler= 1.0;
while (exp >= 100)
{
scaler*= 1.0e100;
result= neg_exp ? result/1.0e100 : result*1.0e100;
exp-= 100;
}
scaler*= scaler10[exp/10]*scaler1[exp%10];
scaler= scaler10[exp/10]*scaler1[exp%10];
if (neg_exp)
result/= scaler;
else