Commit e749f9eb authored by unknown's avatar unknown
Browse files

Merge polly.local:/tmp/22129/bug22129/my41-bug22129 

into  polly.local:/home/kaa/src/maint/m41-maint--07OGk


strings/strtod.c:
  Auto merged
parents 608e10e0 2299727e

mysql-test/r/type_float.result

+7 −0
Original line number Diff line number Diff line
@@ -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

mysql-test/t/type_float.test

+10 −1
Original line number Diff line number Diff line
@@ -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

strings/strtod.c

+43 −24
Original line number Diff line number Diff line
@@ -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)))

  {

    double scaler;

    if (exp < 0)

    {

      exp= -exp;

      neg_exp= 1;                               /* neg_exp was 0 before */

    }

    if (exp + ndigits >= MAX_DBL_EXP + 1 && result)

  tmp_exp= neg_exp ? exp + digits_after_dec_point : exp - digits_after_dec_point;

  if (tmp_exp)

  {

    int order;

    /*

        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

      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

    */

      if (exp + ndigits > MAX_DBL_EXP + 1 ||

          result >= MAX_RESULT_FOR_MAX_EXP)

      {

    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;

        }

      }

    scaler= 1.0;

    }



    exp= tmp_exp;

    if (exp < 0)

    {

      exp= -exp;

      neg_exp= 1;                               /* neg_exp was 0 before */

    }

    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