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/* Copyright (C) 2000 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/*
A quicker atof. About 2-10 times faster than standard atof on sparc.
This don't handle iee-options (NaN...) and the presission :s is a little
less for some high exponential numbers (+-1 at 14th place).
Returns 0.0 if overflow or wrong number.
Must be inited with init_my_atof to handle possibly overflows.
*/
#include <my_global.h>
#ifdef USE_MY_ATOF /* Skipp if we don't want it */
#include <m_ctype.h>
#include <floatingpoint.h>
#include <signal.h>
/* Read a double. If float is wrong return 0.
float ::= [space]* [sign] {digit}+ decimal-point {digit}+ [exponent] |
[sign] {digit}+ [decimal-point {digit}*] exponent |
[sign] {digit}+ decimal-point [{digit}*] exponent |
[sign] decimal-point {digit}* exponent |
exponent :: = exponent-marker [sign] {digit}+
exponent-marker ::= E e
*/
#define is_exponent_marker(ch) (ch == 'E' || ch == 'e')
static void my_atof_overflow _A((int sig,int code, struct sigcontext *scp,
char *addr));
static int parse_sign _A((char **str));
static void parse_float_number_part _A((char **str,double *number, int *length));
static void parse_decimal_number_part _A((char **str,double *number));
static int parse_int_number_part _A((char **str,uint *number));
static int volatile overflow,in_my_atof;
static sigfpe_handler_type old_overflow_handler;
void init_my_atof()
{
old_overflow_handler = (sigfpe_handler_type)
ieee_handler("get", "overflow", old_overflow_handler);
VOID(ieee_handler("set", "overflow", my_atof_overflow));
return;
}
static void my_atof_overflow(sig, code, scp, addr)
int sig;
int code;
struct sigcontext *scp;
char *addr;
{
if (!in_my_atof)
old_overflow_handler(sig,code,scp,addr);
else
overflow=1;
return;
}
double my_atof(src)
const char *src;
{
int sign, exp_sign; /* is number negative (+1) or positive (-1) */
int length_before_point;
double after_point; /* Number after decimal point and before exp */
uint exponent; /* Exponent value */
double exp_log,exp_val;
char *tmp_src;
double result_number;
tmp_src = (char*) src;
while (isspace(tmp_src[0]))
tmp_src++; /* Skipp pre-space */
sign = parse_sign(&tmp_src);
overflow=0;
in_my_atof=1;
parse_float_number_part(&tmp_src, &result_number, &length_before_point);
if (*tmp_src == '.')
{
tmp_src++;
parse_decimal_number_part(&tmp_src, &after_point);
result_number += after_point;
}
else if (length_before_point == 0)
{
in_my_atof=0;
return 0.0;
}
if (is_exponent_marker(*tmp_src))
{
tmp_src++;
exp_sign = parse_sign(&tmp_src);
overflow|=parse_int_number_part(&tmp_src, &exponent);
exp_log=10.0; exp_val=1.0;
for (;;)
{
if (exponent & 1)
{
exp_val*= exp_log;
exponent--;
}
if (!exponent)
break;
exp_log*=exp_log;
exponent>>=1;
}
if (exp_sign < 0)
result_number*=exp_val;
else
result_number/=exp_val;
}
if (sign > 0)
result_number= -result_number;
in_my_atof=0;
if (overflow)
return 0.0;
return result_number;
}
static int parse_sign(str)
char **str;
{
if (**str == '-')
{
(*str)++;
return 1;
}
if (**str == '+')
(*str)++;
return -1;
}
/* Get number with may be separated with ',' */
static void parse_float_number_part(str, number, length)
char **str;
double *number;
int *length;
{
*number = 0;
*length = 0;
for (;;)
{
while (isdigit(**str))
{
(*length)++;
*number = (*number * 10) + (**str - '0');
(*str)++;
}
if (**str != ',')
return; /* Skipp possibly ',' */
(*str)++;
}
}
static void parse_decimal_number_part(str, number)
char **str;
double *number;
{
double exp_log;
*number = 0;
exp_log=1/10.0;
while (isdigit(**str))
{
*number+= (**str - '0')*exp_log;
exp_log/=10;
(*str)++;
}
}
/* Parses int suitably for exponent */
static int parse_int_number_part(str, number)
char **str;
uint *number;
{
*number = 0;
while (isdigit(**str))
{
if (*number >= ((uint) ~0)/10)
return 1; /* Don't overflow */
*number = (*number * 10) + **str - '0';
(*str)++;
}
return 0;
}
#endif
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