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/*
* gawk wrapper for strtod
*/
/*
* Stupid version of System V strtod(3) library routine.
* Does no overflow/underflow checking.
*
* A real number is defined to be
* optional leading white space
* optional sign
* string of digits with optional decimal point
* optional 'e' or 'E'
* followed by optional sign or space
* followed by an integer
*
* if ptr is not NULL a pointer to the character terminating the
* scan is returned in *ptr. If no number formed, *ptr is set to str
* and 0 is returned.
*
* For speed, we don't do the conversion ourselves. Instead, we find
* the end of the number and then call atof() to do the dirty work.
* This bought us a 10% speedup on a sample program at uunet.uu.net.
*
* Fall 2000: Changed to enforce C89 semantics, so that 0x... returns 0.
* C99 has hexadecimal floating point numbers.
*
* Summer 2001. Try to make it smarter, so that a string like "0000"
* doesn't look like we failed. Sigh.
*
* Xmass 2002. Fix a bug in ptr determination, eg. for "0e0".
*/
#if 0
#include <ctype.h>
#endif
extern double atof();
double
gawk_strtod(s, ptr)
register const char *s;
register const char **ptr;
{
const char *start = s; /* save original start of string */
const char *begin = NULL; /* where the number really begins */
int dig = 0;
int dig0 = 0;
/* optional white space */
while (isspace(*s))
s++;
begin = s;
/* optional sign */
if (*s == '+' || *s == '-')
s++;
/* string of digits with optional decimal point */
while (*s == '0') {
s++;
dig0++;
}
while (isdigit(*s)) {
s++;
dig++;
}
if (*s == '.') {
s++;
while (*s == '0') {
s++;
dig0++;
}
while (isdigit(*s)) {
s++;
dig++;
}
}
dig0 += dig; /* any digit has appeared */
/*
* optional 'e' or 'E'
* if a digit (or at least zero) was seen
* followed by optional sign
* followed by an integer
*/
if (dig0
&& (*s == 'e' || *s == 'E')
&& (isdigit(s[1])
|| ((s[1] == '-' || s[1] == '+') && isdigit(s[2])))) {
s++;
if (*s == '+' || *s == '-')
s++;
while (isdigit(*s))
s++;
}
/* In case we haven't found a number, set ptr to start. */
if (ptr)
*ptr = (dig0 ? s : start);
/* Go for it. */
return (dig ? atof(begin) : 0.0);
}
#ifdef TEST
int
main(argc, argv)
int argc;
char **argv;
{
double d;
char *p;
for (argc--, argv++; argc; argc--, argv++) {
d = strtod (*argv, & p);
printf ("%lf [%s]\n", d, p);
}
return 0;
}
#endif
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