[rustc.git] / src / libcore / fmt / num.rs

// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! Integer and floating-point number formatting

#![allow(deprecated)]

// FIXME: #6220 Implement floating point formatting

use prelude::v1::*;

use fmt;
use num::Zero;
use ops::{Div, Rem, Sub};
use str;
use slice;
use ptr;
use mem;

#[doc(hidden)]
trait Int: Zero + PartialEq + PartialOrd + Div<Output=Self> + Rem<Output=Self> +
           Sub<Output=Self> + Copy {
    fn from_u8(u: u8) -> Self;
    fn to_u8(&self) -> u8;
    fn to_u32(&self) -> u32;
    fn to_u64(&self) -> u64;
}

macro_rules! doit {
    ($($t:ident)*) => ($(impl Int for $t {
        fn from_u8(u: u8) -> $t { u as $t }
        fn to_u8(&self) -> u8 { *self as u8 }
        fn to_u32(&self) -> u32 { *self as u32 }
        fn to_u64(&self) -> u64 { *self as u64 }
    })*)
}
doit! { i8 i16 i32 i64 isize u8 u16 u32 u64 usize }

/// A type that represents a specific radix
#[doc(hidden)]
trait GenericRadix {
    /// The number of digits.
    fn base(&self) -> u8;

    /// A radix-specific prefix string.
    fn prefix(&self) -> &'static str {
        ""
    }

    /// Converts an integer to corresponding radix digit.
    fn digit(&self, 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 64
        // characters for a base 2 number.
        let zero = T::zero();
        let is_nonnegative = x >= zero;
        let mut buf = [0; 64];
        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 = 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 = 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 = unsafe { str::from_utf8_unchecked(&buf[curr..]) };
        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 decimal (base 10) radix
#[derive(Clone, PartialEq)]
struct Decimal;

/// 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 {
            fn base(&self) -> u8 { $base }
            fn prefix(&self) -> &'static str { $prefix }
            fn digit(&self, 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 ...  2 => b'0' + x }
radix! { Octal,     8, "0o", x @  0 ...  7 => b'0' + x }
radix! { Decimal,  10, "",   x @  0 ...  9 => 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 {
            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                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 }

const DEC_DIGITS_LUT: &'static[u8] =
    b"0001020304050607080910111213141516171819\
      2021222324252627282930313233343536373839\
      4041424344454647484950515253545556575859\
      6061626364656667686970717273747576777879\
      8081828384858687888990919293949596979899";

macro_rules! impl_Display {
    ($($t:ident),*: $conv_fn:ident) => ($(
    #[stable(feature = "rust1", since = "1.0.0")]
    impl fmt::Display for $t {
        #[allow(unused_comparisons)]
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            let is_nonnegative = *self >= 0;
            let mut n = if is_nonnegative {
                self.$conv_fn()
            } else {
                // convert the negative num to positive by summing 1 to it's 2 complement
                (!self.$conv_fn()).wrapping_add(1)
            };
            let mut buf: [u8; 20] = unsafe { mem::uninitialized() };
            let mut curr = buf.len() as isize;
            let buf_ptr = buf.as_mut_ptr();
            let lut_ptr = DEC_DIGITS_LUT.as_ptr();

            unsafe {
                // eagerly decode 4 characters at a time
                if <$t>::max_value() as u64 >= 10000 {
                    while n >= 10000 {
                        let rem = (n % 10000) as isize;
                        n /= 10000;

                        let d1 = (rem / 100) << 1;
                        let d2 = (rem % 100) << 1;
                        curr -= 4;
                        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) + 48;
                } else {
                    let d1 = n << 1;
                    curr -= 2;
                    ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
                }
            }

            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)
        }
    })*);
}

impl_Display!(i8, u8, i16, u16, i32, u32: to_u32);
impl_Display!(i64, u64: to_u64);
#[cfg(target_pointer_width = "32")]
impl_Display!(isize, usize: to_u32);
#[cfg(target_pointer_width = "64")]
impl_Display!(isize, usize: to_u64);
Commit	Line	Data
1a4d82fc JJ	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.
	4	//
	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.
	10
	11	//! Integer and floating-point number formatting
	12
9cc50fc6 SL	13	#![allow(deprecated)]
9cc50fc6 SL	14
1a4d82fc JJ	15	// FIXME: #6220 Implement floating point formatting
1a4d82fc JJ	16
e9174d1e	17	use prelude::v1::*;
9346a6ac	18
1a4d82fc	19	use fmt;
9346a6ac AL	20	use num::Zero;
9346a6ac AL	21	use ops::{Div, Rem, Sub};
1a4d82fc	22	use str;
c1a9b12d SL	23	use slice;
	24	use ptr;
	25	use mem;
1a4d82fc	26
9346a6ac AL	27	#[doc(hidden)]
	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;
c1a9b12d SL	32	fn to_u32(&self) -> u32;
c1a9b12d SL	33	fn to_u64(&self) -> u64;
9346a6ac AL	34	}
	35
	36	macro_rules! doit {
	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 }
c1a9b12d SL	40	fn to_u32(&self) -> u32 { *self as u32 }
c1a9b12d SL	41	fn to_u64(&self) -> u64 { *self as u64 }
9346a6ac AL	42	})*)
	43	}
	44	doit! { i8 i16 i32 i64 isize u8 u16 u32 u64 usize }
	45
1a4d82fc JJ	46	/// A type that represents a specific radix
	47	#[doc(hidden)]
	48	trait GenericRadix {
	49	/// The number of digits.
	50	fn base(&self) -> u8;
	51
	52	/// A radix-specific prefix string.
b039eaaf SL	53	fn prefix(&self) -> &'static str {
	54	""
	55	}
1a4d82fc JJ	56
	57	/// Converts an integer to corresponding radix digit.
	58	fn digit(&self, x: u8) -> u8;
	59
	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.
9346a6ac	64	let zero = T::zero();
9cc50fc6	65	let is_nonnegative = x >= zero;
c34b1796	66	let mut buf = [0; 64];
1a4d82fc	67	let mut curr = buf.len();
9346a6ac	68	let base = T::from_u8(self.base());
9cc50fc6	69	if is_nonnegative {
1a4d82fc JJ	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() {
9346a6ac AL	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.
1a4d82fc	76	curr -= 1;
b039eaaf SL	77	if x == zero {
	78	// No more digits left to accumulate.
	79	break
	80	};
1a4d82fc JJ	81	}
	82	} else {
	83	// Do the same as above, but accounting for two's complement.
	84	for byte in buf.iter_mut().rev() {
9346a6ac AL	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.
1a4d82fc	88	curr -= 1;
b039eaaf SL	89	if x == zero {
	90	// No more digits left to accumulate.
	91	break
	92	};
1a4d82fc JJ	93	}
	94	}
	95	let buf = unsafe { str::from_utf8_unchecked(&buf[curr..]) };
9cc50fc6	96	f.pad_integral(is_nonnegative, self.prefix(), buf)
1a4d82fc JJ	97	}
	98	}
	99
	100	/// A binary (base 2) radix
	101	#[derive(Clone, PartialEq)]
	102	struct Binary;
	103
	104	/// An octal (base 8) radix
	105	#[derive(Clone, PartialEq)]
	106	struct Octal;
	107
	108	/// A decimal (base 10) radix
	109	#[derive(Clone, PartialEq)]
	110	struct Decimal;
	111
	112	/// A hexadecimal (base 16) radix, formatted with lower-case characters
	113	#[derive(Clone, PartialEq)]
	114	struct LowerHex;
	115
	116	/// A hexadecimal (base 16) radix, formatted with upper-case characters
	117	#[derive(Clone, PartialEq)]
c34b1796	118	struct UpperHex;
1a4d82fc JJ	119
	120	macro_rules! radix {
	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 {
	126	match x {
	127	$($x => $conv,)+
	128	x => panic!("number not in the range 0..{}: {}", self.base() - 1, x),
	129	}
	130	}
	131	}
	132	}
	133	}
	134
	135	radix! { Binary, 2, "0b", x @ 0 ... 2 => b'0' + x }
	136	radix! { Octal, 8, "0o", x @ 0 ... 7 => b'0' + x }
	137	radix! { Decimal, 10, "", x @ 0 ... 9 => b'0' + x }
	138	radix! { LowerHex, 16, "0x", x @ 0 ... 9 => b'0' + x,
	139	x @ 10 ... 15 => b'a' + (x - 10) }
	140	radix! { UpperHex, 16, "0x", x @ 0 ... 9 => b'0' + x,
	141	x @ 10 ... 15 => b'A' + (x - 10) }
	142
1a4d82fc JJ	143	macro_rules! int_base {
1a4d82fc JJ	144	($Trait:ident for $T:ident as $U:ident -> $Radix:ident) => {
85aaf69f	145	#[stable(feature = "rust1", since = "1.0.0")]
1a4d82fc JJ	146	impl fmt::$Trait for $T {
	147	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	148	$Radix.fmt_int(*self as $U, f)
	149	}
	150	}
	151	}
	152	}
	153
c34b1796 AL	154	macro_rules! debug {
c34b1796 AL	155	($T:ident) => {
85aaf69f SL	156	#[stable(feature = "rust1", since = "1.0.0")]
85aaf69f SL	157	impl fmt::Debug for $T {
1a4d82fc	158	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
85aaf69f	159	fmt::Display::fmt(self, f)
1a4d82fc JJ	160	}
	161	}
	162	}
	163	}
c1a9b12d	164
1a4d82fc JJ	165	macro_rules! integer {
1a4d82fc JJ	166	($Int:ident, $Uint:ident) => {
1a4d82fc JJ	167	int_base! { Binary for $Int as $Uint -> Binary }
	168	int_base! { Octal for $Int as $Uint -> Octal }
	169	int_base! { LowerHex for $Int as $Uint -> LowerHex }
	170	int_base! { UpperHex for $Int as $Uint -> UpperHex }
c34b1796	171	debug! { $Int }
1a4d82fc	172
1a4d82fc JJ	173	int_base! { Binary for $Uint as $Uint -> Binary }
	174	int_base! { Octal for $Uint as $Uint -> Octal }
	175	int_base! { LowerHex for $Uint as $Uint -> LowerHex }
	176	int_base! { UpperHex for $Uint as $Uint -> UpperHex }
c34b1796	177	debug! { $Uint }
1a4d82fc JJ	178	}
1a4d82fc JJ	179	}
c34b1796	180	integer! { isize, usize }
1a4d82fc JJ	181	integer! { i8, u8 }
	182	integer! { i16, u16 }
	183	integer! { i32, u32 }
	184	integer! { i64, u64 }
c1a9b12d SL	185
	186	const DEC_DIGITS_LUT: &'static[u8] =
	187	b"0001020304050607080910111213141516171819\
	188	2021222324252627282930313233343536373839\
	189	4041424344454647484950515253545556575859\
	190	6061626364656667686970717273747576777879\
	191	8081828384858687888990919293949596979899";
	192
	193	macro_rules! impl_Display {
	194	($($t:ident),*: $conv_fn:ident) => ($(
92a42be0	195	#[stable(feature = "rust1", since = "1.0.0")]
c1a9b12d SL	196	impl fmt::Display for $t {
	197	#[allow(unused_comparisons)]
	198	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
9cc50fc6 SL	199	let is_nonnegative = *self >= 0;
9cc50fc6 SL	200	let mut n = if is_nonnegative {
c1a9b12d SL	201	self.$conv_fn()
	202	} else {
	203	// convert the negative num to positive by summing 1 to it's 2 complement
	204	(!self.$conv_fn()).wrapping_add(1)
	205	};
	206	let mut buf: [u8; 20] = unsafe { mem::uninitialized() };
	207	let mut curr = buf.len() as isize;
	208	let buf_ptr = buf.as_mut_ptr();
	209	let lut_ptr = DEC_DIGITS_LUT.as_ptr();
	210
	211	unsafe {
	212	// eagerly decode 4 characters at a time
	213	if <$t>::max_value() as u64 >= 10000 {
	214	while n >= 10000 {
	215	let rem = (n % 10000) as isize;
	216	n /= 10000;
	217
	218	let d1 = (rem / 100) << 1;
	219	let d2 = (rem % 100) << 1;
	220	curr -= 4;
	221	ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
	222	ptr::copy_nonoverlapping(lut_ptr.offset(d2), buf_ptr.offset(curr + 2), 2);
	223	}
	224	}
	225
	226	// if we reach here numbers are <= 9999, so at most 4 chars long
	227	let mut n = n as isize; // possibly reduce 64bit math
	228
	229	// decode 2 more chars, if > 2 chars
	230	if n >= 100 {
	231	let d1 = (n % 100) << 1;
	232	n /= 100;
	233	curr -= 2;
	234	ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
	235	}
	236
	237	// decode last 1 or 2 chars
	238	if n < 10 {
	239	curr -= 1;
	240	*buf_ptr.offset(curr) = (n as u8) + 48;
	241	} else {
	242	let d1 = n << 1;
	243	curr -= 2;
	244	ptr::copy_nonoverlapping(lut_ptr.offset(d1), buf_ptr.offset(curr), 2);
	245	}
	246	}
	247
	248	let buf_slice = unsafe {
	249	str::from_utf8_unchecked(
	250	slice::from_raw_parts(buf_ptr.offset(curr), buf.len() - curr as usize))
	251	};
9cc50fc6	252	f.pad_integral(is_nonnegative, "", buf_slice)
c1a9b12d SL	253	}
	254	})*);
	255	}
	256
	257	impl_Display!(i8, u8, i16, u16, i32, u32: to_u32);
	258	impl_Display!(i64, u64: to_u64);
	259	#[cfg(target_pointer_width = "32")]
	260	impl_Display!(isize, usize: to_u32);
	261	#[cfg(target_pointer_width = "64")]
	262	impl_Display!(isize, usize: to_u64);