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use core::fmt;
use awint_internals::*;
use const_fn::const_fn;
use SerdeError::*;
use crate::Bits;
/// Runs all pre serialization checks except for equal width and `Overflow`
/// checks
const fn verify_for_bytes_(src: &[u8], radix: u8) -> Result<(), SerdeError> {
if radix < 2 || radix > 36 {
return Err(InvalidRadix)
}
const_for!(i in {0..src.len()} {
let b = src[i];
if b == b'_' {
continue;
}
let in_decimal_range = b'0' <= b && b < b'0'.wrapping_add(if radix < 10 {radix} else {10});
let in_lower_range = (radix > 10)
&& (b'a' <= b)
&& (b < b'a'.wrapping_add(radix).wrapping_sub(10));
let in_upper_range = (radix > 10)
&& (b'A' <= b)
&& (b < b'A'.wrapping_add(radix).wrapping_sub(10));
if radix <= 10 {
if !in_decimal_range {
return Err(InvalidChar)
}
} else if !(in_decimal_range || in_lower_range || in_upper_range) {
return Err(InvalidChar)
}
});
Ok(())
}
/// # `const` string representation conversion
///
/// Note: the `awint_ext` crate has higher level allocating functions
/// `Awi::bits_to_string_radix`, `Awi::bits_to_vec_radix`, and
/// `<Awi as FromStr>::from_str`
impl Bits {
/// A version of [Bits::bytes_radix_] optimized for power of two
/// radixes
#[doc(hidden)]
#[const_fn(cfg(feature = "const_support"))]
pub const fn power_of_two_bytes_(
&mut self,
sign: Option<bool>,
src: &[u8],
radix: u8,
pad: &mut Self,
) -> Result<(), SerdeError> {
if self.bw() != pad.bw() {
return Err(NonEqualWidths)
}
if !radix.is_power_of_two() {
return Err(InvalidRadix)
}
let log2 = radix.trailing_zeros() as usize;
if let Err(e) = verify_for_bytes_(src, radix) {
return Err(e)
}
// the accumulator
pad.zero_();
let mut shl = 0;
const_for!(i in {0..src.len()}.rev() {
let b = src[i];
if b == b'_' {
continue;
}
let char_digit = if b <= b'9' {
b.wrapping_sub(b'0')
} else if b <= b'Z' {
b.wrapping_sub(b'A').wrapping_add(10)
} else {
b.wrapping_sub(b'a').wrapping_add(10)
} as Digit;
pad.digit_or_(char_digit, shl);
shl += log2;
if shl >= self.bw() {
let tmp = if let Some(tmp) = BITS
.wrapping_sub(char_digit.leading_zeros() as usize).checked_add(shl) {
if let Some(tmp) = tmp.checked_sub(log2) {
tmp
} else {
return Err(Overflow)
}
} else {
return Err(Overflow)
};
// check that the last digit did not cross the end
if tmp > self.bw() {
return Err(Overflow)
}
// there may be a bunch of leading zeros, so do not return an error yet
const_for!(j in {0..i} {
match src[j] {
b'_' | b'0' => (),
_ => return Err(Overflow)
}
});
break
}
});
if let Some(sign) = sign {
if sign {
if pad.lz() == 0 && !pad.is_imin() {
// These cannot be represented as negative
return Err(Overflow)
}
// handles `imin` correctly
pad.neg_(true);
} else if pad.lz() == 0 {
// These cannot be represented as positive
return Err(Overflow)
}
}
self.copy_(pad).unwrap();
Ok(())
}
/// Assigns to `self` the integer value represented by `src` in the given
/// `radix`. If `src` should be interpreted as unsigned, `sign` should be
/// `None`, otherwise it should be set to the sign. In order for this
/// function to be `const`, two scratchpads `pad0` and `pad1` with the
/// same bitwidth as `self` must be supplied, which can be mutated by
/// the function in arbitrary ways.
///
/// # Errors
///
/// `self` is not mutated if an error occurs. See [crate::SerdeError] for
/// error conditions. The characters `0..=9`, `a..=z`, and `A..=Z` are
/// allowed depending on the radix. The char `_` is ignored, and all
/// other chars result in an error. `src` cannot be empty. The value of
/// the string must be representable in the bitwidth of `self` with the
/// specified sign, otherwise an overflow error is returned.
#[const_fn(cfg(feature = "const_support"))]
pub const fn bytes_radix_(
&mut self,
sign: Option<bool>,
src: &[u8],
radix: u8,
pad0: &mut Self,
pad1: &mut Self,
) -> Result<(), SerdeError> {
if (self.bw() != pad0.bw()) || (self.bw() != pad1.bw()) {
return Err(NonEqualWidths)
}
if radix.is_power_of_two() {
return self.power_of_two_bytes_(sign, src, radix, pad0)
}
if let Err(e) = verify_for_bytes_(src, radix) {
return Err(e)
}
// the accumulator
pad0.zero_();
// contains the radix exponential
pad1.uone_();
const_for!(i in {0..src.len()}.rev() {
let b = src[i];
if b == b'_' {
continue;
}
let char_digit = if radix <= 10 || b <= b'9' {
b.wrapping_sub(b'0')
} else if b <= b'Z' {
b.wrapping_sub(b'A').wrapping_add(10)
} else {
b.wrapping_sub(b'a').wrapping_add(10)
} as Digit;
let o0 = pad0.digit_mul_add_(pad1, char_digit).unwrap();
if o0 {
return Err(Overflow)
}
let o1 = pad1.digit_cin_mul_(0, radix as Digit);
if o1 != 0 {
// there may be a bunch of leading zeros, so do not return an error yet
const_for!(j in {0..i} {
match src[j] {
b'_' | b'0' => (),
_ => return Err(Overflow)
}
});
break
}
});
if let Some(sign) = sign {
if sign {
if pad0.lz() == 0 && !pad0.is_imin() {
// These cannot be represented as negative
return Err(Overflow)
}
// handles `imin` correctly
pad0.neg_(true);
} else if pad0.lz() == 0 {
// These cannot be represented as positive
return Err(Overflow)
}
}
self.copy_(pad0).unwrap();
Ok(())
}
/// Assigns the `[u8]` representation of `self` to `dst` (sign indicators,
/// prefixes, and postfixes not included). `signed` specifies if `self`
/// should be interpreted as signed. `radix` specifies the radix, and
/// `upper` specifies if letters should be uppercase. In order for this
/// function to be `const`, a scratchpad `pad` with the same bitwidth as
/// `self` must be supplied. Note that if `dst.len()` is more than what
/// is needed to store the representation, the leading bytes will all be
/// set to b'0'.
///
/// # Errors
///
/// Note: If an error is returned, `dst` may be set to anything
///
/// This function can fail from `NonEqualWidths`, `InvalidRadix`, and
/// `Overflow` (if `dst` cannot represent the value of `self`). See
/// [crate::SerdeError].
#[const_fn(cfg(feature = "const_support"))]
pub const fn to_bytes_radix(
&self,
signed: bool,
dst: &mut [u8],
radix: u8,
upper: bool,
pad: &mut Self,
) -> Result<(), SerdeError> {
// there's going to be a lot of potential for downstream confusion if we do not
// check
self.assert_cleared_unused_bits();
if self.bw() != pad.bw() {
return Err(NonEqualWidths)
}
if radix < 2 || radix > 36 {
return Err(InvalidRadix)
}
pad.copy_(self).unwrap();
// happens to do the right thing to `imin`
pad.neg_(signed && pad.msb());
const_for!(i in {0..dst.len()}.rev() {
let rem = pad.digit_udivide_inplace_(radix as Digit).unwrap() as u8;
if rem < 10 {
dst[i] = b'0'.wrapping_add(rem);
} else if upper {
dst[i] = b'A'.wrapping_add(rem).wrapping_sub(10);
} else {
dst[i] = b'a'.wrapping_add(rem).wrapping_sub(10);
}
});
if !pad.is_zero() {
Err(Overflow)
} else {
Ok(())
}
}
/// Writes the bits content as hexadecimal to `f`, with underscores every 8
/// digits. I have decided on including the "0x" prefix and bitwidth suffix
/// always, because it is confusing in `assert_` debugging otherwise.
#[inline]
pub(crate) fn debug_format_hexadecimal(
&self,
f: &mut fmt::Formatter,
upper: bool,
) -> fmt::Result {
self.assert_cleared_unused_bits();
f.write_fmt(format_args!("0x"))?;
const_for!(j0 in {0..(self.bw() >> 2).wrapping_add(1)}.rev() {
if (self.get_digit(j0 << 2) & 0b1111) != 0 {
// we have reached the first nonzero character
const_for!(j1 in {0..j0.wrapping_add(1)}.rev() {
let mut char_digit = (self.get_digit(j1 << 2) & 0b1111) as u8;
if char_digit < 10 {
char_digit += b'0';
} else if upper {
char_digit += b'A'.wrapping_sub(10);
} else {
char_digit += b'a'.wrapping_sub(10);
}
// Safety: we strictly capped the range of possible values above with `& 0b1111`
let c = unsafe { char::from_u32_unchecked(char_digit as u32) };
f.write_fmt(format_args!("{c}"))?;
if ((j1 % 8) == 0) && (j1 != 0) {
f.write_fmt(format_args!("_"))?;
}
});
break
}
if j0 == 0 {
// we have reached the end without printing anything, print at least one '0'
f.write_fmt(format_args!("{}", '0'))?;
}
});
f.write_fmt(format_args!("_u{}", self.bw()))
}
#[inline]
pub(crate) fn debug_format_octal(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.assert_cleared_unused_bits();
f.write_fmt(format_args!("0o"))?;
const_for!(j0 in {0..(self.bw() / 3).wrapping_add(1)}.rev() {
if (self.get_digit(j0.wrapping_mul(3)) & 0b111) != 0 {
// we have reached the first nonzero character
const_for!(j1 in {0..j0.wrapping_add(1)}.rev() {
let mut char_digit = (self.get_digit(j1.wrapping_mul(3)) & 0b111) as u8;
char_digit += b'0';
// Safety: we strictly capped the range of possible values above with `& 0b111`
let c = unsafe { char::from_u32_unchecked(char_digit as u32) };
if let Err(e) = f.write_fmt(format_args!("{c}")) {
return Err(e)
}
if ((j1 % 8) == 0) && (j1 != 0) {
f.write_fmt(format_args!("_"))?;
}
});
break
}
if j0 == 0 {
// we have reached the end without printing anything, print at least one '0'
f.write_fmt(format_args!("{}", '0'))?;
}
});
f.write_fmt(format_args!("_u{}", self.bw()))
}
// TODO this could be optimized
#[inline]
pub(crate) fn debug_format_binary(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.assert_cleared_unused_bits();
f.write_fmt(format_args!("0b"))?;
const_for!(j0 in {0..self.bw()}.rev() {
if (self.get_digit(j0) & 0b1) != 0 {
// we have reached the first nonzero character
const_for!(j1 in {0..(j0 + 1)}.rev() {
let mut char_digit = (self.get_digit(j1) & 0b1) as u8;
char_digit += b'0';
// Safety: we strictly capped the range of possible values above with `& 0b1`
let c = unsafe { char::from_u32_unchecked(char_digit as u32) };
if let Err(e) = f.write_fmt(format_args!("{c}")) {
return Err(e)
}
if ((j1 % 8) == 0) && (j1 != 0) {
f.write_fmt(format_args!("_"))?;
}
});
break
}
if j0 == 0 {
// we have reached the end without printing anything, print at least one '0'
f.write_fmt(format_args!("{}", '0'))?;
}
});
f.write_fmt(format_args!("_u{}", self.bw()))
}
}