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sscanf: Use strtof() instead of strtod() if a short floating point value was requested. The should help performance with MCUs with 32-bit FPU support

This commit is contained in:
Gregory Nutt 2016-10-22 13:42:43 -06:00
parent d08596a653
commit 177239feae
1 changed files with 35 additions and 16 deletions
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51
libc/stdio/lib_sscanf.c
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@ -511,9 +511,9 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
else if (strchr("aAfFeEgG", *fmt) != NULL)
{
#ifdef CONFIG_HAVE_DOUBLE
FAR double_t *pd = NULL;
FAR double *pd = NULL;
#endif
FAR float *pf = NULL;
FAR float *pf = NULL;
linfo("vsscanf: Performing floating point conversion\n");
@ -531,7 +531,7 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
#ifdef CONFIG_HAVE_DOUBLE
if (lflag)
{
pd = va_arg(ap, FAR double_t *);
pd = va_arg(ap, FAR double *);
*pd = 0.0;
}
else
@ -581,22 +581,11 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
FAR char *endptr;
int errsave;
double_t dvalue;
/* Preserve the errno value */
errsave = get_errno();
set_errno(0);
dvalue = strtod(tmp, &endptr);
/* Check if the number was successfully converted */
if (tmp == endptr || get_errno() == ERANGE)
{
return count;
}
set_errno(errsave);
/* We have to check whether we need to return a float
* or a double.
@ -605,14 +594,44 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
#ifdef CONFIG_HAVE_DOUBLE
if (lflag)
{
/* Get the converted double value */
double dvalue = strtod(tmp, &endptr);
/* Check if the number was successfully converted */
if (tmp == endptr || get_errno() == ERANGE)
{
return count;
}
set_errno(errsave);
/* Return the double value */
linfo("vsscanf: Return %f to %p\n", dvalue, pd);
*pd = dvalue;
}
else
#endif
{
linfo("vsscanf: Return %f to %p\n", dvalue, pf);
*pf = (float)dvalue;
/* Get the converted float value */
float fvalue = strtof(tmp, &endptr);
/* Check if the number was successfully converted */
if (tmp == endptr || get_errno() == ERANGE)
{
return count;
}
set_errno(errsave);
/* Return the float value */
linfo("vsscanf: Return %f to %p\n", (double)fvalue, pf);
*pf = fvalue;
}
count++;