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 $T {
161 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
162 if f.debug_lower_hex() {
163 fmt::LowerHex::fmt(self, f)
164 } else if f.debug_upper_hex() {
165 fmt::UpperHex::fmt(self, f)
167 fmt::Display::fmt(self, f)
174 macro_rules! integer {
175 ($Int:ident, $Uint:ident) => {
176 int_base! { Binary for $Int as $Uint -> Binary }
177 int_base! { Octal for $Int as $Uint -> Octal }
178 int_base! { LowerHex for $Int as $Uint -> LowerHex }
179 int_base! { UpperHex for $Int as $Uint -> UpperHex }
182 int_base! { Binary for $Uint as $Uint -> Binary }
183 int_base! { Octal for $Uint as $Uint -> Octal }
184 int_base! { LowerHex for $Uint as $Uint -> LowerHex }
185 int_base! { UpperHex for $Uint as $Uint -> UpperHex }
189 integer! { isize, usize }
191 integer! { i16, u16 }
192 integer! { i32, u32 }
193 integer! { i64, u64 }
194 integer! { i128, u128 }
196 const DEC_DIGITS_LUT: &'static[u8] =
197 b"0001020304050607080910111213141516171819\
198 2021222324252627282930313233343536373839\
199 4041424344454647484950515253545556575859\
200 6061626364656667686970717273747576777879\
201 8081828384858687888990919293949596979899";
203 macro_rules! impl_Display {
204 ($($t:ident),*: $conv_fn:ident) => ($(
205 #[stable(feature = "rust1", since = "1.0.0")]
206 impl fmt::Display for $t {
207 #[allow(unused_comparisons)]
208 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
209 let is_nonnegative = *self >= 0;
210 let mut n = if is_nonnegative {
213 // convert the negative num to positive by summing 1 to it's 2 complement
214 (!self.$conv_fn()).wrapping_add(1)
216 let mut buf: [u8; 39] = unsafe { mem::uninitialized() };
217 let mut curr = buf.len() as isize;
218 let buf_ptr = buf.as_mut_ptr();
219 let lut_ptr = DEC_DIGITS_LUT.as_ptr();
222 // need at least 16 bits for the 4-characters-at-a-time to work.
223 if ::mem::size_of::<$t>() >= 2 {
224 // eagerly decode 4 characters at a time
226 let rem = (n % 10000) as isize;
229 let d1 = (rem / 100) << 1;
230 let d2 = (rem % 100) << 1;
232 ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
233 ptr::copy_nonoverlapping(lut_ptr.offset(d2), buf_ptr.offset(curr + 2), 2);
237 // if we reach here numbers are <= 9999, so at most 4 chars long
238 let mut n = n as isize; // possibly reduce 64bit math
240 // decode 2 more chars, if > 2 chars
242 let d1 = (n % 100) << 1;
245 ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
248 // decode last 1 or 2 chars
251 *buf_ptr.offset(curr) = (n as u8) + b'0';
255 ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
259 let buf_slice = unsafe {
260 str::from_utf8_unchecked(
261 slice::from_raw_parts(buf_ptr.offset(curr), buf.len() - curr as usize))
263 f.pad_integral(is_nonnegative, "", buf_slice)
268 impl_Display!(i8, u8, i16, u16, i32, u32: to_u32);
269 impl_Display!(i64, u64: to_u64);
270 impl_Display!(i128, u128: to_u128);
271 #[cfg(target_pointer_width = "16")]
272 impl_Display!(isize, usize: to_u16);
273 #[cfg(target_pointer_width = "32")]
274 impl_Display!(isize, usize: to_u32);
275 #[cfg(target_pointer_width = "64")]
276 impl_Display!(isize, usize: to_u64);