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
);