diff options
Diffstat (limited to 'src/libcore/fmt/num.rs')
| -rw-r--r-- | src/libcore/fmt/num.rs | 463 |
1 files changed, 0 insertions, 463 deletions
diff --git a/src/libcore/fmt/num.rs b/src/libcore/fmt/num.rs deleted file mode 100644 index 7d77e33d743..00000000000 --- a/src/libcore/fmt/num.rs +++ /dev/null @@ -1,463 +0,0 @@ -//! Integer and floating-point number formatting - -use crate::fmt; -use crate::mem::MaybeUninit; -use crate::num::flt2dec; -use crate::ops::{Div, Rem, Sub}; -use crate::ptr; -use crate::slice; -use crate::str; - -#[doc(hidden)] -trait Int: - PartialEq + PartialOrd + Div<Output = Self> + Rem<Output = Self> + Sub<Output = Self> + Copy -{ - fn zero() -> Self; - fn from_u8(u: u8) -> Self; - fn to_u8(&self) -> u8; - fn to_u16(&self) -> u16; - fn to_u32(&self) -> u32; - fn to_u64(&self) -> u64; - fn to_u128(&self) -> u128; -} - -macro_rules! doit { - ($($t:ident)*) => ($(impl Int for $t { - fn zero() -> Self { 0 } - fn from_u8(u: u8) -> Self { u as Self } - fn to_u8(&self) -> u8 { *self as u8 } - fn to_u16(&self) -> u16 { *self as u16 } - fn to_u32(&self) -> u32 { *self as u32 } - fn to_u64(&self) -> u64 { *self as u64 } - fn to_u128(&self) -> u128 { *self as u128 } - })*) -} -doit! { i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize } - -/// A type that represents a specific radix -#[doc(hidden)] -trait GenericRadix { - /// The number of digits. - const BASE: u8; - - /// A radix-specific prefix string. - const PREFIX: &'static str; - - /// Converts an integer to corresponding radix digit. - fn digit(x: u8) -> u8; - - /// Format an integer using the radix using a formatter. - fn fmt_int<T: Int>(&self, mut x: T, f: &mut fmt::Formatter<'_>) -> fmt::Result { - // The radix can be as low as 2, so we need a buffer of at least 128 - // characters for a base 2 number. - let zero = T::zero(); - let is_nonnegative = x >= zero; - let mut buf = [MaybeUninit::<u8>::uninit(); 128]; - let mut curr = buf.len(); - let base = T::from_u8(Self::BASE); - if is_nonnegative { - // Accumulate each digit of the number from the least significant - // to the most significant figure. - for byte in buf.iter_mut().rev() { - let n = x % base; // Get the current place value. - x = x / base; // Deaccumulate the number. - byte.write(Self::digit(n.to_u8())); // Store the digit in the buffer. - curr -= 1; - if x == zero { - // No more digits left to accumulate. - break; - }; - } - } else { - // Do the same as above, but accounting for two's complement. - for byte in buf.iter_mut().rev() { - let n = zero - (x % base); // Get the current place value. - x = x / base; // Deaccumulate the number. - byte.write(Self::digit(n.to_u8())); // Store the digit in the buffer. - curr -= 1; - if x == zero { - // No more digits left to accumulate. - break; - }; - } - } - let buf = &buf[curr..]; - // SAFETY: The only chars in `buf` are created by `Self::digit` which are assumed to be - // valid UTF-8 - let buf = unsafe { - str::from_utf8_unchecked(slice::from_raw_parts(MaybeUninit::first_ptr(buf), buf.len())) - }; - f.pad_integral(is_nonnegative, Self::PREFIX, buf) - } -} - -/// A binary (base 2) radix -#[derive(Clone, PartialEq)] -struct Binary; - -/// An octal (base 8) radix -#[derive(Clone, PartialEq)] -struct Octal; - -/// A hexadecimal (base 16) radix, formatted with lower-case characters -#[derive(Clone, PartialEq)] -struct LowerHex; - -/// A hexadecimal (base 16) radix, formatted with upper-case characters -#[derive(Clone, PartialEq)] -struct UpperHex; - -macro_rules! radix { - ($T:ident, $base:expr, $prefix:expr, $($x:pat => $conv:expr),+) => { - impl GenericRadix for $T { - const BASE: u8 = $base; - const PREFIX: &'static str = $prefix; - fn digit(x: u8) -> u8 { - match x { - $($x => $conv,)+ - x => panic!("number not in the range 0..={}: {}", Self::BASE - 1, x), - } - } - } - } -} - -radix! { Binary, 2, "0b", x @ 0 ..= 1 => b'0' + x } -radix! { Octal, 8, "0o", x @ 0 ..= 7 => b'0' + x } -radix! { LowerHex, 16, "0x", x @ 0 ..= 9 => b'0' + x, -x @ 10 ..= 15 => b'a' + (x - 10) } -radix! { UpperHex, 16, "0x", x @ 0 ..= 9 => b'0' + x, -x @ 10 ..= 15 => b'A' + (x - 10) } - -macro_rules! int_base { - ($Trait:ident for $T:ident as $U:ident -> $Radix:ident) => { - #[stable(feature = "rust1", since = "1.0.0")] - impl fmt::$Trait for $T { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - $Radix.fmt_int(*self as $U, f) - } - } - }; -} - -macro_rules! debug { - ($T:ident) => { - #[stable(feature = "rust1", since = "1.0.0")] - impl fmt::Debug for $T { - #[inline] - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - if f.debug_lower_hex() { - fmt::LowerHex::fmt(self, f) - } else if f.debug_upper_hex() { - fmt::UpperHex::fmt(self, f) - } else { - fmt::Display::fmt(self, f) - } - } - } - }; -} - -macro_rules! integer { - ($Int:ident, $Uint:ident) => { - int_base! { Binary for $Int as $Uint -> Binary } - int_base! { Octal for $Int as $Uint -> Octal } - int_base! { LowerHex for $Int as $Uint -> LowerHex } - int_base! { UpperHex for $Int as $Uint -> UpperHex } - debug! { $Int } - - int_base! { Binary for $Uint as $Uint -> Binary } - int_base! { Octal for $Uint as $Uint -> Octal } - int_base! { LowerHex for $Uint as $Uint -> LowerHex } - int_base! { UpperHex for $Uint as $Uint -> UpperHex } - debug! { $Uint } - }; -} -integer! { isize, usize } -integer! { i8, u8 } -integer! { i16, u16 } -integer! { i32, u32 } -integer! { i64, u64 } -integer! { i128, u128 } - -static DEC_DIGITS_LUT: &[u8; 200] = b"0001020304050607080910111213141516171819\ - 2021222324252627282930313233343536373839\ - 4041424344454647484950515253545556575859\ - 6061626364656667686970717273747576777879\ - 8081828384858687888990919293949596979899"; - -macro_rules! impl_Display { - ($($t:ident),* as $u:ident via $conv_fn:ident named $name:ident) => { - fn $name(mut n: $u, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::Result { - // 2^128 is about 3*10^38, so 39 gives an extra byte of space - let mut buf = [MaybeUninit::<u8>::uninit(); 39]; - let mut curr = buf.len() as isize; - let buf_ptr = MaybeUninit::first_ptr_mut(&mut buf); - let lut_ptr = DEC_DIGITS_LUT.as_ptr(); - - // SAFETY: Since `d1` and `d2` are always less than or equal to `198`, we - // can copy from `lut_ptr[d1..d1 + 1]` and `lut_ptr[d2..d2 + 1]`. To show - // that it's OK to copy into `buf_ptr`, notice that at the beginning - // `curr == buf.len() == 39 > log(n)` since `n < 2^128 < 10^39`, and at - // each step this is kept the same as `n` is divided. Since `n` is always - // non-negative, this means that `curr > 0` so `buf_ptr[curr..curr + 1]` - // is safe to access. - unsafe { - // need at least 16 bits for the 4-characters-at-a-time to work. - assert!(crate::mem::size_of::<$u>() >= 2); - - // eagerly decode 4 characters at a time - while n >= 10000 { - let rem = (n % 10000) as isize; - n /= 10000; - - let d1 = (rem / 100) << 1; - let d2 = (rem % 100) << 1; - curr -= 4; - - // We are allowed to copy to `buf_ptr[curr..curr + 3]` here since - // otherwise `curr < 0`. But then `n` was originally at least `10000^10` - // which is `10^40 > 2^128 > n`. - ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2); - ptr::copy_nonoverlapping(lut_ptr.offset(d2), buf_ptr.offset(curr + 2), 2); - } - - // if we reach here numbers are <= 9999, so at most 4 chars long - let mut n = n as isize; // possibly reduce 64bit math - - // decode 2 more chars, if > 2 chars - if n >= 100 { - let d1 = (n % 100) << 1; - n /= 100; - curr -= 2; - ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2); - } - - // decode last 1 or 2 chars - if n < 10 { - curr -= 1; - *buf_ptr.offset(curr) = (n as u8) + b'0'; - } else { - let d1 = n << 1; - curr -= 2; - ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2); - } - } - - // SAFETY: `curr` > 0 (since we made `buf` large enough), and all the chars are valid - // UTF-8 since `DEC_DIGITS_LUT` is - let buf_slice = unsafe { - str::from_utf8_unchecked( - slice::from_raw_parts(buf_ptr.offset(curr), buf.len() - curr as usize)) - }; - f.pad_integral(is_nonnegative, "", buf_slice) - } - - $( - #[stable(feature = "rust1", since = "1.0.0")] - impl fmt::Display for $t { - #[allow(unused_comparisons)] - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - let is_nonnegative = *self >= 0; - let n = if is_nonnegative { - self.$conv_fn() - } else { - // convert the negative num to positive by summing 1 to it's 2 complement - (!self.$conv_fn()).wrapping_add(1) - }; - $name(n, is_nonnegative, f) - } - })* - }; -} - -macro_rules! impl_Exp { - ($($t:ident),* as $u:ident via $conv_fn:ident named $name:ident) => { - fn $name( - mut n: $u, - is_nonnegative: bool, - upper: bool, - f: &mut fmt::Formatter<'_> - ) -> fmt::Result { - let (mut n, mut exponent, trailing_zeros, added_precision) = { - let mut exponent = 0; - // count and remove trailing decimal zeroes - while n % 10 == 0 && n >= 10 { - n /= 10; - exponent += 1; - } - let trailing_zeros = exponent; - - let (added_precision, subtracted_precision) = match f.precision() { - Some(fmt_prec) => { - // number of decimal digits minus 1 - let mut tmp = n; - let mut prec = 0; - while tmp >= 10 { - tmp /= 10; - prec += 1; - } - (fmt_prec.saturating_sub(prec), prec.saturating_sub(fmt_prec)) - } - None => (0,0) - }; - for _ in 1..subtracted_precision { - n/=10; - exponent += 1; - } - if subtracted_precision != 0 { - let rem = n % 10; - n /= 10; - exponent += 1; - // round up last digit - if rem >= 5 { - n += 1; - } - } - (n, exponent, trailing_zeros, added_precision) - }; - - // 39 digits (worst case u128) + . = 40 - // Since `curr` always decreases by the number of digits copied, this means - // that `curr >= 0`. - let mut buf = [MaybeUninit::<u8>::uninit(); 40]; - let mut curr = buf.len() as isize; //index for buf - let buf_ptr = MaybeUninit::first_ptr_mut(&mut buf); - let lut_ptr = DEC_DIGITS_LUT.as_ptr(); - - // decode 2 chars at a time - while n >= 100 { - let d1 = ((n % 100) as isize) << 1; - curr -= 2; - // SAFETY: `d1 <= 198`, so we can copy from `lut_ptr[d1..d1 + 2]` since - // `DEC_DIGITS_LUT` has a length of 200. - unsafe { - ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2); - } - n /= 100; - exponent += 2; - } - // n is <= 99, so at most 2 chars long - let mut n = n as isize; // possibly reduce 64bit math - // decode second-to-last character - if n >= 10 { - curr -= 1; - // SAFETY: Safe since `40 > curr >= 0` (see comment) - unsafe { - *buf_ptr.offset(curr) = (n as u8 % 10_u8) + b'0'; - } - n /= 10; - exponent += 1; - } - // add decimal point iff >1 mantissa digit will be printed - if exponent != trailing_zeros || added_precision != 0 { - curr -= 1; - // SAFETY: Safe since `40 > curr >= 0` - unsafe { - *buf_ptr.offset(curr) = b'.'; - } - } - - // SAFETY: Safe since `40 > curr >= 0` - let buf_slice = unsafe { - // decode last character - curr -= 1; - *buf_ptr.offset(curr) = (n as u8) + b'0'; - - let len = buf.len() - curr as usize; - slice::from_raw_parts(buf_ptr.offset(curr), len) - }; - - // stores 'e' (or 'E') and the up to 2-digit exponent - let mut exp_buf = [MaybeUninit::<u8>::uninit(); 3]; - let exp_ptr = MaybeUninit::first_ptr_mut(&mut exp_buf); - // SAFETY: In either case, `exp_buf` is written within bounds and `exp_ptr[..len]` - // is contained within `exp_buf` since `len <= 3`. - let exp_slice = unsafe { - *exp_ptr.offset(0) = if upper {b'E'} else {b'e'}; - let len = if exponent < 10 { - *exp_ptr.offset(1) = (exponent as u8) + b'0'; - 2 - } else { - let off = exponent << 1; - ptr::copy_nonoverlapping(lut_ptr.offset(off), exp_ptr.offset(1), 2); - 3 - }; - slice::from_raw_parts(exp_ptr, len) - }; - - let parts = &[ - flt2dec::Part::Copy(buf_slice), - flt2dec::Part::Zero(added_precision), - flt2dec::Part::Copy(exp_slice) - ]; - let sign = if !is_nonnegative { - "-" - } else if f.sign_plus() { - "+" - } else { - "" - }; - let formatted = flt2dec::Formatted{sign, parts}; - f.pad_formatted_parts(&formatted) - } - - $( - #[stable(feature = "integer_exp_format", since = "1.42.0")] - impl fmt::LowerExp for $t { - #[allow(unused_comparisons)] - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - let is_nonnegative = *self >= 0; - let n = if is_nonnegative { - self.$conv_fn() - } else { - // convert the negative num to positive by summing 1 to it's 2 complement - (!self.$conv_fn()).wrapping_add(1) - }; - $name(n, is_nonnegative, false, f) - } - })* - $( - #[stable(feature = "integer_exp_format", since = "1.42.0")] - impl fmt::UpperExp for $t { - #[allow(unused_comparisons)] - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - let is_nonnegative = *self >= 0; - let n = if is_nonnegative { - self.$conv_fn() - } else { - // convert the negative num to positive by summing 1 to it's 2 complement - (!self.$conv_fn()).wrapping_add(1) - }; - $name(n, is_nonnegative, true, f) - } - })* - }; -} - -// Include wasm32 in here since it doesn't reflect the native pointer size, and -// often cares strongly about getting a smaller code size. -#[cfg(any(target_pointer_width = "64", target_arch = "wasm32"))] -mod imp { - use super::*; - impl_Display!( - i8, u8, i16, u16, i32, u32, i64, u64, usize, isize - as u64 via to_u64 named fmt_u64 - ); - impl_Exp!( - i8, u8, i16, u16, i32, u32, i64, u64, usize, isize - as u64 via to_u64 named exp_u64 - ); -} - -#[cfg(not(any(target_pointer_width = "64", target_arch = "wasm32")))] -mod imp { - use super::*; - impl_Display!(i8, u8, i16, u16, i32, u32, isize, usize as u32 via to_u32 named fmt_u32); - impl_Display!(i64, u64 as u64 via to_u64 named fmt_u64); - impl_Exp!(i8, u8, i16, u16, i32, u32, isize, usize as u32 via to_u32 named exp_u32); - impl_Exp!(i64, u64 as u64 via to_u64 named exp_u64); -} - -impl_Display!(i128, u128 as u128 via to_u128 named fmt_u128); -impl_Exp!(i128, u128 as u128 via to_u128 named exp_u128); |