JL_DLLEXPORT jl_nullable_float32_t jl_try_substrtof(char *str, size_t offset, size_t len)
{
char *p;
char *bstr = str+offset;
char *pend = bstr+len;
char *tofree = NULL;
int hasvalue = 0;
errno = 0;
if (!(*pend == '\0' || isspace((unsigned char)*pend) || *pend == ',')) {
// confusing data outside substring. must copy.
char *newstr;
if (len + 1 < jl_page_size) {
newstr = (char*)alloca(len + 1);
}
else {
newstr = tofree = (char*)malloc(len + 1);
}
memcpy(newstr, bstr, len);
newstr[len] = 0;
bstr = newstr;
pend = bstr+len;
}
#if defined(_OS_WINDOWS_) && !defined(_COMPILER_MINGW_)
float out = (float)jl_strtod_c(bstr, &p);
#else
float out = jl_strtof_c(bstr, &p);
#endif
if (errno==ERANGE && (out==0 || out==HUGE_VALF || out==-HUGE_VALF)) {
hasvalue = 0;
}
else if (p == bstr) {
hasvalue = 0;
}
else {
// Deal with case where the substring might be something like "1 ",
// which is OK, and "1 X", which we don't allow.
hasvalue = substr_isspace(p, pend) ? 1 : 0;
}
if (__unlikely(tofree))
free(tofree);
jl_nullable_float32_t ret = {(uint8_t)hasvalue, out};
return ret;
}