1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Integer and floating-point number formatting
17 use ops::{Div, Rem, Sub};
24 trait Int: PartialEq + PartialOrd + Div<Output=Self> + Rem<Output=Self> +
25 Sub<Output=Self> + Copy {
27 fn from_u8(u: u8) -> Self;
28 fn to_u8(&self) -> u8;
29 fn to_u16(&self) -> u16;
30 fn to_u32(&self) -> u32;
31 fn to_u64(&self) -> u64;
32 fn to_u128(&self) -> u128;
36 ($($t:ident)*) => ($(impl Int for $t {
38 fn from_u8(u: u8) -> $t { u as $t }
39 fn to_u8(&self) -> u8 { *self as u8 }
40 fn to_u16(&self) -> u16 { *self as u16 }
41 fn to_u32(&self) -> u32 { *self as u32 }
42 fn to_u64(&self) -> u64 { *self as u64 }
43 fn to_u128(&self) -> u128 { *self as u128 }
46 doit! { i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize }
48 /// A type that represents a specific radix
51 /// The number of digits.
54 /// A radix-specific prefix string.
55 fn prefix(&self) -> &'static str {
59 /// Converts an integer to corresponding radix digit.
60 fn digit(&self, x: u8) -> u8;
62 /// Format an integer using the radix using a formatter.
63 fn fmt_int<T: Int>(&self, mut x: T, f: &mut fmt::Formatter) -> fmt::Result {
64 // The radix can be as low as 2, so we need a buffer of at least 128
65 // characters for a base 2 number.
67 let is_nonnegative = x >= zero;
68 let mut buf = [0; 128];
69 let mut curr = buf.len();
70 let base = T::from_u8(self.base());
72 // Accumulate each digit of the number from the least significant
73 // to the most significant figure.
74 for byte in buf.iter_mut().rev() {
75 let n = x % base; // Get the current place value.
76 x = x / base; // Deaccumulate the number.
77 *byte = self.digit(n.to_u8()); // Store the digit in the buffer.
80 // No more digits left to accumulate.
85 // Do the same as above, but accounting for two's complement.
86 for byte in buf.iter_mut().rev() {
87 let n = zero - (x % base); // Get the current place value.
88 x = x / base; // Deaccumulate the number.
89 *byte = self.digit(n.to_u8()); // Store the digit in the buffer.
92 // No more digits left to accumulate.
97 let buf = unsafe { str::from_utf8_unchecked(&buf[curr..]) };
98 f.pad_integral(is_nonnegative, self.prefix(), buf)
102 /// A binary (base 2) radix
103 #[derive(Clone, PartialEq)]
106 /// An octal (base 8) radix
107 #[derive(Clone, PartialEq)]
110 /// A decimal (base 10) radix
111 #[derive(Clone, PartialEq)]
114 /// A hexadecimal (base 16) radix, formatted with lower-case characters
115 #[derive(Clone, PartialEq)]
118 /// A hexadecimal (base 16) radix, formatted with upper-case characters
119 #[derive(Clone, PartialEq)]
123 ($T:ident, $base:expr, $prefix:expr, $($x:pat => $conv:expr),+) => {
124 impl GenericRadix for $T {
125 fn base(&self) -> u8 { $base }
126 fn prefix(&self) -> &'static str { $prefix }
127 fn digit(&self, x: u8) -> u8 {
130 x => panic!("number not in the range 0..{}: {}", self.base() - 1, x),
137 radix! { Binary, 2, "0b", x @ 0 ... 1 => b'0' + x }
138 radix! { Octal, 8, "0o", x @ 0 ... 7 => b'0' + x }
139 radix! { Decimal, 10, "", x @ 0 ... 9 => b'0' + x }
140 radix! { LowerHex, 16, "0x", x @ 0 ... 9 => b'0' + x,
141 x @ 10 ... 15 => b'a' + (x - 10) }
142 radix! { UpperHex, 16, "0x", x @ 0 ... 9 => b'0' + x,
143 x @ 10 ... 15 => b'A' + (x - 10) }
145 macro_rules! int_base {
146 ($Trait:ident for $T:ident as $U:ident -> $Radix:ident) => {
147 #[stable(feature = "rust1", since = "1.0.0")]
148 impl fmt::$Trait for $T {
149 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
150 $Radix.fmt_int(*self as $U, f)
158 #[stable(feature = "rust1", since = "1.0.0")]
159 impl fmt::Debug for $T {
161 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
162 fmt::Display::fmt(self, f)
168 macro_rules! integer {
169 ($Int:ident, $Uint:ident) => {
170 int_base! { Binary for $Int as $Uint -> Binary }
171 int_base! { Octal for $Int as $Uint -> Octal }
172 int_base! { LowerHex for $Int as $Uint -> LowerHex }
173 int_base! { UpperHex for $Int as $Uint -> UpperHex }
176 int_base! { Binary for $Uint as $Uint -> Binary }
177 int_base! { Octal for $Uint as $Uint -> Octal }
178 int_base! { LowerHex for $Uint as $Uint -> LowerHex }
179 int_base! { UpperHex for $Uint as $Uint -> UpperHex }
183 integer! { isize, usize }
185 integer! { i16, u16 }
186 integer! { i32, u32 }
187 integer! { i64, u64 }
188 integer! { i128, u128 }
190 const DEC_DIGITS_LUT: &'static[u8] =
191 b"0001020304050607080910111213141516171819\
192 2021222324252627282930313233343536373839\
193 4041424344454647484950515253545556575859\
194 6061626364656667686970717273747576777879\
195 8081828384858687888990919293949596979899";
197 macro_rules! impl_Display {
198 ($($t:ident),*: $conv_fn:ident) => ($(
199 #[stable(feature = "rust1", since = "1.0.0")]
200 impl fmt::Display for $t {
201 #[allow(unused_comparisons)]
202 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
203 let is_nonnegative = *self >= 0;
204 let mut n = if is_nonnegative {
207 // convert the negative num to positive by summing 1 to it's 2 complement
208 (!self.$conv_fn()).wrapping_add(1)
210 let mut buf: [u8; 39] = unsafe { mem::uninitialized() };
211 let mut curr = buf.len() as isize;
212 let buf_ptr = buf.as_mut_ptr();
213 let lut_ptr = DEC_DIGITS_LUT.as_ptr();
216 // need at least 16 bits for the 4-characters-at-a-time to work.
217 if ::mem::size_of::<$t>() >= 2 {
218 // eagerly decode 4 characters at a time
220 let rem = (n % 10000) as isize;
223 let d1 = (rem / 100) << 1;
224 let d2 = (rem % 100) << 1;
226 ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
227 ptr::copy_nonoverlapping(lut_ptr.offset(d2), buf_ptr.offset(curr + 2), 2);
231 // if we reach here numbers are <= 9999, so at most 4 chars long
232 let mut n = n as isize; // possibly reduce 64bit math
234 // decode 2 more chars, if > 2 chars
236 let d1 = (n % 100) << 1;
239 ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
242 // decode last 1 or 2 chars
245 *buf_ptr.offset(curr) = (n as u8) + b'0';
249 ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
253 let buf_slice = unsafe {
254 str::from_utf8_unchecked(
255 slice::from_raw_parts(buf_ptr.offset(curr), buf.len() - curr as usize))
257 f.pad_integral(is_nonnegative, "", buf_slice)
262 impl_Display!(i8, u8, i16, u16, i32, u32: to_u32);
263 impl_Display!(i64, u64: to_u64);
264 impl_Display!(i128, u128: to_u128);
265 #[cfg(target_pointer_width = "16")]
266 impl_Display!(isize, usize: to_u16);
267 #[cfg(target_pointer_width = "32")]
268 impl_Display!(isize, usize: to_u32);
269 #[cfg(target_pointer_width = "64")]
270 impl_Display!(isize, usize: to_u64);