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strtof(), strtod(): handle NaN and Infinity

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This commit is contained in:
Florian Meißner
2023-06-05 23:04:25 +00:00
committed by Jeremy Soller
parent fe02a5bd98
commit b66df46f33
5 changed files with 114 additions and 61 deletions
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src/macros.rs
+74 -61
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@@ -227,19 +227,19 @@ macro_rules! strto_impl {
num
}};
}
#[macro_export]
macro_rules! strto_float_impl {
($type:ident, $s:expr, $endptr:expr) => {{
let mut s = $s;
let endptr = $endptr;
// TODO: Handle named floats: NaN, Inf...
while ctype::isspace(*s as c_int) != 0 {
s = s.offset(1);
}
let mut result: $type = 0.0;
let mut exponent: Option<$type> = None;
let mut radix = 10;
let result_sign = match *s as u8 {
@@ -254,75 +254,88 @@ macro_rules! strto_float_impl {
_ => 1.0,
};
if *s as u8 == b'0' && *s.offset(1) as u8 == b'x' {
s = s.offset(2);
radix = 16;
}
let rust_s = CStr::from_ptr(s).to_string_lossy();
while let Some(digit) = (*s as u8 as char).to_digit(radix) {
result *= radix as $type;
result += digit as $type;
s = s.offset(1);
}
// detect NaN, Inf
if rust_s.to_lowercase().starts_with("inf") {
result = $type::INFINITY;
s = s.offset(3);
} else if rust_s.to_lowercase().starts_with("nan") {
// we cannot signal negative NaN in LLVM backed languages
// https://github.com/rust-lang/rust/issues/73328 , https://github.com/rust-lang/rust/issues/81261
result = $type::NAN;
s = s.offset(3);
} else {
if *s as u8 == b'0' && *s.offset(1) as u8 == b'x' {
s = s.offset(2);
radix = 16;
}
if *s as u8 == b'.' {
s = s.offset(1);
let mut i = 1.0;
while let Some(digit) = (*s as u8 as char).to_digit(radix) {
i *= radix as $type;
result += digit as $type / i;
result *= radix as $type;
result += digit as $type;
s = s.offset(1);
}
}
let s_before_exponent = s;
let exponent = match (*s as u8, radix) {
(b'e' | b'E', 10) | (b'p' | b'P', 16) => {
if *s as u8 == b'.' {
s = s.offset(1);
let is_exponent_positive = match *s as u8 {
b'-' => {
s = s.offset(1);
false
}
b'+' => {
s = s.offset(1);
true
}
_ => true,
};
// Exponent digits are always in base 10.
if (*s as u8 as char).is_digit(10) {
let mut exponent_value = 0;
while let Some(digit) = (*s as u8 as char).to_digit(10) {
exponent_value *= 10;
exponent_value += digit;
s = s.offset(1);
}
let exponent_base = match radix {
10 => 10u128,
16 => 2u128,
_ => unreachable!(),
};
if is_exponent_positive {
Some(exponent_base.pow(exponent_value) as $type)
} else {
Some(1.0 / (exponent_base.pow(exponent_value) as $type))
}
} else {
// Exponent had no valid digits after 'e'/'p' and '+'/'-', rollback
s = s_before_exponent;
None
let mut i = 1.0;
while let Some(digit) = (*s as u8 as char).to_digit(radix) {
i *= radix as $type;
result += digit as $type / i;
s = s.offset(1);
}
}
_ => None,
};
let s_before_exponent = s;
exponent = match (*s as u8, radix) {
(b'e' | b'E', 10) | (b'p' | b'P', 16) => {
s = s.offset(1);
let is_exponent_positive = match *s as u8 {
b'-' => {
s = s.offset(1);
false
}
b'+' => {
s = s.offset(1);
true
}
_ => true,
};
// Exponent digits are always in base 10.
if (*s as u8 as char).is_digit(10) {
let mut exponent_value = 0;
while let Some(digit) = (*s as u8 as char).to_digit(10) {
exponent_value *= 10;
exponent_value += digit;
s = s.offset(1);
}
let exponent_base = match radix {
10 => 10u128,
16 => 2u128,
_ => unreachable!(),
};
if is_exponent_positive {
Some(exponent_base.pow(exponent_value) as $type)
} else {
Some(1.0 / (exponent_base.pow(exponent_value) as $type))
}
} else {
// Exponent had no valid digits after 'e'/'p' and '+'/'-', rollback
s = s_before_exponent;
None
}
}
_ => None,
};
}
if !endptr.is_null() {
// This is stupid, but apparently strto* functions want