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
15 // FIXME: #6220 Implement floating point formatting
21 use ops::{Div, Rem, Sub};
28 trait Int: Zero + PartialEq + PartialOrd + Div<Output=Self> + Rem<Output=Self> +
29 Sub<Output=Self> + Copy {
30 fn from_u8(u: u8) -> Self;
31 fn to_u8(&self) -> u8;
32 fn to_u32(&self) -> u32;
33 fn to_u64(&self) -> u64;
37 ($($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_u32(&self) -> u32 { *self as u32 }
41 fn to_u64(&self) -> u64 { *self as u64 }
44 doit! { i8 i16 i32 i64 isize u8 u16 u32 u64 usize }
46 /// A type that represents a specific radix
49 /// The number of digits.
52 /// A radix-specific prefix string.
53 fn prefix(&self) -> &'static str {
57 /// Converts an integer to corresponding radix digit.
58 fn digit(&self, x: u8) -> u8;
60 /// Format an integer using the radix using a formatter.
61 fn fmt_int<T: Int>(&self, mut x: T, f: &mut fmt::Formatter) -> fmt::Result {
62 // The radix can be as low as 2, so we need a buffer of at least 64
63 // characters for a base 2 number.
65 let is_nonnegative = x >= zero;
66 let mut buf = [0; 64];
67 let mut curr = buf.len();
68 let base = T::from_u8(self.base());
70 // Accumulate each digit of the number from the least significant
71 // to the most significant figure.
72 for byte in buf.iter_mut().rev() {
73 let n = x % base; // Get the current place value.
74 x = x / base; // Deaccumulate the number.
75 *byte = self.digit(n.to_u8()); // Store the digit in the buffer.
78 // No more digits left to accumulate.
83 // Do the same as above, but accounting for two's complement.
84 for byte in buf.iter_mut().rev() {
85 let n = zero - (x % base); // Get the current place value.
86 x = x / base; // Deaccumulate the number.
87 *byte = self.digit(n.to_u8()); // Store the digit in the buffer.
90 // No more digits left to accumulate.
95 let buf = unsafe { str::from_utf8_unchecked(&buf[curr..]) };
96 f.pad_integral(is_nonnegative, self.prefix(), buf)
100 /// A binary (base 2) radix
101 #[derive(Clone, PartialEq)]
104 /// An octal (base 8) radix
105 #[derive(Clone, PartialEq)]
108 /// A decimal (base 10) radix
109 #[derive(Clone, PartialEq)]
112 /// A hexadecimal (base 16) radix, formatted with lower-case characters
113 #[derive(Clone, PartialEq)]
116 /// A hexadecimal (base 16) radix, formatted with upper-case characters
117 #[derive(Clone, PartialEq)]
121 ($T:ident, $base:expr, $prefix:expr, $($x:pat => $conv:expr),+) => {
122 impl GenericRadix for $T {
123 fn base(&self) -> u8 { $base }
124 fn prefix(&self) -> &'static str { $prefix }
125 fn digit(&self, x: u8) -> u8 {
128 x => panic!("number not in the range 0..{}: {}", self.base() - 1, x),
135 radix! { Binary, 2, "0b", x @ 0 ... 2 => b'0' + x }
136 radix! { Octal, 8, "0o", x @ 0 ... 7 => b'0' + x }
137 radix! { Decimal, 10, "", x @ 0 ... 9 => b'0' + x }
138 radix! { LowerHex, 16, "0x", x @ 0 ... 9 => b'0' + x,
139 x @ 10 ... 15 => b'a' + (x - 10) }
140 radix! { UpperHex, 16, "0x", x @ 0 ... 9 => b'0' + x,
141 x @ 10 ... 15 => b'A' + (x - 10) }
143 /// A radix with in the range of `2..36`.
144 #[derive(Clone, Copy, PartialEq)]
145 #[unstable(feature = "fmt_radix",
146 reason = "may be renamed or move to a different module",
148 #[rustc_deprecated(since = "1.7.0", reason = "not used enough to stabilize")]
154 fn new(base: u8) -> Radix {
155 assert!(2 <= base && base <= 36,
156 "the base must be in the range of 2..36: {}",
162 impl GenericRadix for Radix {
163 fn base(&self) -> u8 {
166 fn digit(&self, x: u8) -> u8 {
168 x @ 0 ... 9 => b'0' + x,
169 x if x < self.base() => b'a' + (x - 10),
170 x => panic!("number not in the range 0..{}: {}", self.base() - 1, x),
175 /// A helper type for formatting radixes.
176 #[unstable(feature = "fmt_radix",
177 reason = "may be renamed or move to a different module",
179 #[rustc_deprecated(since = "1.7.0", reason = "not used enough to stabilize")]
180 #[derive(Copy, Clone)]
181 pub struct RadixFmt<T, R>(T, R);
183 /// Constructs a radix formatter in the range of `2..36`.
188 /// #![feature(fmt_radix)]
190 /// use std::fmt::radix;
191 /// assert_eq!(format!("{}", radix(55, 36)), "1j".to_string());
193 #[unstable(feature = "fmt_radix",
194 reason = "may be renamed or move to a different module",
196 #[rustc_deprecated(since = "1.7.0", reason = "not used enough to stabilize")]
197 pub fn radix<T>(x: T, base: u8) -> RadixFmt<T, Radix> {
198 RadixFmt(x, Radix::new(base))
201 macro_rules! radix_fmt {
202 ($T:ty as $U:ty, $fmt:ident) => {
203 #[stable(feature = "rust1", since = "1.0.0")]
204 impl fmt::Debug for RadixFmt<$T, Radix> {
205 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
206 fmt::Display::fmt(self, f)
209 #[stable(feature = "rust1", since = "1.0.0")]
210 impl fmt::Display for RadixFmt<$T, Radix> {
211 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
212 match *self { RadixFmt(ref x, radix) => radix.$fmt(*x as $U, f) }
218 macro_rules! int_base {
219 ($Trait:ident for $T:ident as $U:ident -> $Radix:ident) => {
220 #[stable(feature = "rust1", since = "1.0.0")]
221 impl fmt::$Trait for $T {
222 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
223 $Radix.fmt_int(*self as $U, f)
231 #[stable(feature = "rust1", since = "1.0.0")]
232 impl fmt::Debug for $T {
233 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
234 fmt::Display::fmt(self, f)
240 macro_rules! integer {
241 ($Int:ident, $Uint:ident) => {
242 int_base! { Binary for $Int as $Uint -> Binary }
243 int_base! { Octal for $Int as $Uint -> Octal }
244 int_base! { LowerHex for $Int as $Uint -> LowerHex }
245 int_base! { UpperHex for $Int as $Uint -> UpperHex }
246 radix_fmt! { $Int as $Int, fmt_int }
249 int_base! { Binary for $Uint as $Uint -> Binary }
250 int_base! { Octal for $Uint as $Uint -> Octal }
251 int_base! { LowerHex for $Uint as $Uint -> LowerHex }
252 int_base! { UpperHex for $Uint as $Uint -> UpperHex }
253 radix_fmt! { $Uint as $Uint, fmt_int }
257 integer! { isize, usize }
259 integer! { i16, u16 }
260 integer! { i32, u32 }
261 integer! { i64, u64 }
263 const DEC_DIGITS_LUT: &'static[u8] =
264 b"0001020304050607080910111213141516171819\
265 2021222324252627282930313233343536373839\
266 4041424344454647484950515253545556575859\
267 6061626364656667686970717273747576777879\
268 8081828384858687888990919293949596979899";
270 macro_rules! impl_Display {
271 ($($t:ident),*: $conv_fn:ident) => ($(
272 #[stable(feature = "rust1", since = "1.0.0")]
273 impl fmt::Display for $t {
274 #[allow(unused_comparisons)]
275 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
276 let is_nonnegative = *self >= 0;
277 let mut n = if is_nonnegative {
280 // convert the negative num to positive by summing 1 to it's 2 complement
281 (!self.$conv_fn()).wrapping_add(1)
283 let mut buf: [u8; 20] = unsafe { mem::uninitialized() };
284 let mut curr = buf.len() as isize;
285 let buf_ptr = buf.as_mut_ptr();
286 let lut_ptr = DEC_DIGITS_LUT.as_ptr();
289 // eagerly decode 4 characters at a time
290 if <$t>::max_value() as u64 >= 10000 {
292 let rem = (n % 10000) as isize;
295 let d1 = (rem / 100) << 1;
296 let d2 = (rem % 100) << 1;
298 ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
299 ptr::copy_nonoverlapping(lut_ptr.offset(d2), buf_ptr.offset(curr + 2), 2);
303 // if we reach here numbers are <= 9999, so at most 4 chars long
304 let mut n = n as isize; // possibly reduce 64bit math
306 // decode 2 more chars, if > 2 chars
308 let d1 = (n % 100) << 1;
311 ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
314 // decode last 1 or 2 chars
317 *buf_ptr.offset(curr) = (n as u8) + 48;
321 ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
325 let buf_slice = unsafe {
326 str::from_utf8_unchecked(
327 slice::from_raw_parts(buf_ptr.offset(curr), buf.len() - curr as usize))
329 f.pad_integral(is_nonnegative, "", buf_slice)
334 impl_Display!(i8, u8, i16, u16, i32, u32: to_u32);
335 impl_Display!(i64, u64: to_u64);
336 #[cfg(target_pointer_width = "32")]
337 impl_Display!(isize, usize: to_u32);
338 #[cfg(target_pointer_width = "64")]
339 impl_Display!(isize, usize: to_u64);