| // Copyright 2013-2015 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. |
| |
| //! Utilities for formatting and printing strings. |
| |
| #![stable(feature = "rust1", since = "1.0.0")] |
| |
| use prelude::v1::*; |
| |
| use cell::{UnsafeCell, Cell, RefCell, Ref, RefMut, BorrowState}; |
| use marker::PhantomData; |
| use mem; |
| use num::flt2dec; |
| use ops::Deref; |
| use result; |
| use slice; |
| use str; |
| |
| #[unstable(feature = "fmt_flags_align", issue = "27726")] |
| /// Possible alignments returned by `Formatter::align` |
| #[derive(Debug)] |
| pub enum Alignment { |
| /// Indication that contents should be left-aligned. |
| Left, |
| /// Indication that contents should be right-aligned. |
| Right, |
| /// Indication that contents should be center-aligned. |
| Center, |
| /// No alignment was requested. |
| Unknown, |
| } |
| |
| #[stable(feature = "debug_builders", since = "1.2.0")] |
| pub use self::builders::{DebugStruct, DebugTuple, DebugSet, DebugList, DebugMap}; |
| |
| mod num; |
| mod builders; |
| |
| #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
| issue = "0")] |
| #[doc(hidden)] |
| pub mod rt { |
| pub mod v1; |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| /// The type returned by formatter methods. |
| pub type Result = result::Result<(), Error>; |
| |
| /// The error type which is returned from formatting a message into a stream. |
| /// |
| /// This type does not support transmission of an error other than that an error |
| /// occurred. Any extra information must be arranged to be transmitted through |
| /// some other means. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[derive(Copy, Clone, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)] |
| pub struct Error; |
| |
| /// A collection of methods that are required to format a message into a stream. |
| /// |
| /// This trait is the type which this modules requires when formatting |
| /// information. This is similar to the standard library's `io::Write` trait, |
| /// but it is only intended for use in libcore. |
| /// |
| /// This trait should generally not be implemented by consumers of the standard |
| /// library. The `write!` macro accepts an instance of `io::Write`, and the |
| /// `io::Write` trait is favored over implementing this trait. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub trait Write { |
| /// Writes a slice of bytes into this writer, returning whether the write |
| /// succeeded. |
| /// |
| /// This method can only succeed if the entire byte slice was successfully |
| /// written, and this method will not return until all data has been |
| /// written or an error occurs. |
| /// |
| /// # Errors |
| /// |
| /// This function will return an instance of `Error` on error. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn write_str(&mut self, s: &str) -> Result; |
| |
| /// Writes a `char` into this writer, returning whether the write succeeded. |
| /// |
| /// A single `char` may be encoded as more than one byte. |
| /// This method can only succeed if the entire byte sequence was successfully |
| /// written, and this method will not return until all data has been |
| /// written or an error occurs. |
| /// |
| /// # Errors |
| /// |
| /// This function will return an instance of `Error` on error. |
| #[stable(feature = "fmt_write_char", since = "1.1.0")] |
| fn write_char(&mut self, c: char) -> Result { |
| self.write_str(unsafe { |
| str::from_utf8_unchecked(c.encode_utf8().as_slice()) |
| }) |
| } |
| |
| /// Glue for usage of the `write!` macro with implementors of this trait. |
| /// |
| /// This method should generally not be invoked manually, but rather through |
| /// the `write!` macro itself. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn write_fmt(&mut self, args: Arguments) -> Result { |
| // This Adapter is needed to allow `self` (of type `&mut |
| // Self`) to be cast to a Write (below) without |
| // requiring a `Sized` bound. |
| struct Adapter<'a,T: ?Sized +'a>(&'a mut T); |
| |
| impl<'a, T: ?Sized> Write for Adapter<'a, T> |
| where T: Write |
| { |
| fn write_str(&mut self, s: &str) -> Result { |
| self.0.write_str(s) |
| } |
| |
| fn write_char(&mut self, c: char) -> Result { |
| self.0.write_char(c) |
| } |
| |
| fn write_fmt(&mut self, args: Arguments) -> Result { |
| self.0.write_fmt(args) |
| } |
| } |
| |
| write(&mut Adapter(self), args) |
| } |
| } |
| |
| #[stable(feature = "fmt_write_blanket_impl", since = "1.4.0")] |
| impl<'a, W: Write + ?Sized> Write for &'a mut W { |
| fn write_str(&mut self, s: &str) -> Result { |
| (**self).write_str(s) |
| } |
| |
| fn write_char(&mut self, c: char) -> Result { |
| (**self).write_char(c) |
| } |
| |
| fn write_fmt(&mut self, args: Arguments) -> Result { |
| (**self).write_fmt(args) |
| } |
| } |
| |
| /// A struct to represent both where to emit formatting strings to and how they |
| /// should be formatted. A mutable version of this is passed to all formatting |
| /// traits. |
| #[allow(missing_debug_implementations)] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub struct Formatter<'a> { |
| flags: u32, |
| fill: char, |
| align: rt::v1::Alignment, |
| width: Option<usize>, |
| precision: Option<usize>, |
| |
| buf: &'a mut (Write+'a), |
| curarg: slice::Iter<'a, ArgumentV1<'a>>, |
| args: &'a [ArgumentV1<'a>], |
| } |
| |
| // NB. Argument is essentially an optimized partially applied formatting function, |
| // equivalent to `exists T.(&T, fn(&T, &mut Formatter) -> Result`. |
| |
| enum Void {} |
| |
| /// This struct represents the generic "argument" which is taken by the Xprintf |
| /// family of functions. It contains a function to format the given value. At |
| /// compile time it is ensured that the function and the value have the correct |
| /// types, and then this struct is used to canonicalize arguments to one type. |
| #[derive(Copy)] |
| #[allow(missing_debug_implementations)] |
| #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
| issue = "0")] |
| #[doc(hidden)] |
| pub struct ArgumentV1<'a> { |
| value: &'a Void, |
| formatter: fn(&Void, &mut Formatter) -> Result, |
| } |
| |
| #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
| issue = "0")] |
| impl<'a> Clone for ArgumentV1<'a> { |
| fn clone(&self) -> ArgumentV1<'a> { |
| *self |
| } |
| } |
| |
| impl<'a> ArgumentV1<'a> { |
| #[inline(never)] |
| fn show_usize(x: &usize, f: &mut Formatter) -> Result { |
| Display::fmt(x, f) |
| } |
| |
| #[doc(hidden)] |
| #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
| issue = "0")] |
| pub fn new<'b, T>(x: &'b T, |
| f: fn(&T, &mut Formatter) -> Result) -> ArgumentV1<'b> { |
| unsafe { |
| ArgumentV1 { |
| formatter: mem::transmute(f), |
| value: mem::transmute(x) |
| } |
| } |
| } |
| |
| #[doc(hidden)] |
| #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
| issue = "0")] |
| pub fn from_usize(x: &usize) -> ArgumentV1 { |
| ArgumentV1::new(x, ArgumentV1::show_usize) |
| } |
| |
| fn as_usize(&self) -> Option<usize> { |
| if self.formatter as usize == ArgumentV1::show_usize as usize { |
| Some(unsafe { *(self.value as *const _ as *const usize) }) |
| } else { |
| None |
| } |
| } |
| } |
| |
| // flags available in the v1 format of format_args |
| #[derive(Copy, Clone)] |
| #[allow(dead_code)] // SignMinus isn't currently used |
| enum FlagV1 { SignPlus, SignMinus, Alternate, SignAwareZeroPad, } |
| |
| impl<'a> Arguments<'a> { |
| /// When using the format_args!() macro, this function is used to generate the |
| /// Arguments structure. |
| #[doc(hidden)] #[inline] |
| #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
| issue = "0")] |
| pub fn new_v1(pieces: &'a [&'a str], |
| args: &'a [ArgumentV1<'a>]) -> Arguments<'a> { |
| Arguments { |
| pieces: pieces, |
| fmt: None, |
| args: args |
| } |
| } |
| |
| /// This function is used to specify nonstandard formatting parameters. |
| /// The `pieces` array must be at least as long as `fmt` to construct |
| /// a valid Arguments structure. Also, any `Count` within `fmt` that is |
| /// `CountIsParam` or `CountIsNextParam` has to point to an argument |
| /// created with `argumentusize`. However, failing to do so doesn't cause |
| /// unsafety, but will ignore invalid . |
| #[doc(hidden)] #[inline] |
| #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
| issue = "0")] |
| pub fn new_v1_formatted(pieces: &'a [&'a str], |
| args: &'a [ArgumentV1<'a>], |
| fmt: &'a [rt::v1::Argument]) -> Arguments<'a> { |
| Arguments { |
| pieces: pieces, |
| fmt: Some(fmt), |
| args: args |
| } |
| } |
| } |
| |
| /// This structure represents a safely precompiled version of a format string |
| /// and its arguments. This cannot be generated at runtime because it cannot |
| /// safely be done so, so no constructors are given and the fields are private |
| /// to prevent modification. |
| /// |
| /// The `format_args!` macro will safely create an instance of this structure |
| /// and pass it to a function or closure, passed as the first argument. The |
| /// macro validates the format string at compile-time so usage of the `write` |
| /// and `format` functions can be safely performed. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[derive(Copy, Clone)] |
| pub struct Arguments<'a> { |
| // Format string pieces to print. |
| pieces: &'a [&'a str], |
| |
| // Placeholder specs, or `None` if all specs are default (as in "{}{}"). |
| fmt: Option<&'a [rt::v1::Argument]>, |
| |
| // Dynamic arguments for interpolation, to be interleaved with string |
| // pieces. (Every argument is preceded by a string piece.) |
| args: &'a [ArgumentV1<'a>], |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a> Debug for Arguments<'a> { |
| fn fmt(&self, fmt: &mut Formatter) -> Result { |
| Display::fmt(self, fmt) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a> Display for Arguments<'a> { |
| fn fmt(&self, fmt: &mut Formatter) -> Result { |
| write(fmt.buf, *self) |
| } |
| } |
| |
| /// Format trait for the `?` character. |
| /// |
| /// `Debug` should format the output in a programmer-facing, debugging context. |
| /// |
| /// Generally speaking, you should just `derive` a `Debug` implementation. |
| /// |
| /// When used with the alternate format specifier `#?`, the output is pretty-printed. |
| /// |
| /// For more information on formatters, see [the module-level documentation][module]. |
| /// |
| /// [module]: ../../std/fmt/index.html |
| /// |
| /// This trait can be used with `#[derive]` if all fields implement `Debug`. When |
| /// `derive`d for structs, it will use the name of the `struct`, then `{`, then a |
| /// comma-separated list of each field's name and `Debug` value, then `}`. For |
| /// `enum`s, it will use the name of the variant and, if applicable, `(`, then the |
| /// `Debug` values of the fields, then `)`. |
| /// |
| /// # Examples |
| /// |
| /// Deriving an implementation: |
| /// |
| /// ``` |
| /// #[derive(Debug)] |
| /// struct Point { |
| /// x: i32, |
| /// y: i32, |
| /// } |
| /// |
| /// let origin = Point { x: 0, y: 0 }; |
| /// |
| /// println!("The origin is: {:?}", origin); |
| /// ``` |
| /// |
| /// Manually implementing: |
| /// |
| /// ``` |
| /// use std::fmt; |
| /// |
| /// struct Point { |
| /// x: i32, |
| /// y: i32, |
| /// } |
| /// |
| /// impl fmt::Debug for Point { |
| /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| /// write!(f, "Point {{ x: {}, y: {} }}", self.x, self.y) |
| /// } |
| /// } |
| /// |
| /// let origin = Point { x: 0, y: 0 }; |
| /// |
| /// println!("The origin is: {:?}", origin); |
| /// ``` |
| /// |
| /// This outputs: |
| /// |
| /// ```text |
| /// The origin is: Point { x: 0, y: 0 } |
| /// ``` |
| /// |
| /// There are a number of `debug_*` methods on `Formatter` to help you with manual |
| /// implementations, such as [`debug_struct`][debug_struct]. |
| /// |
| /// `Debug` implementations using either `derive` or the debug builder API |
| /// on `Formatter` support pretty printing using the alternate flag: `{:#?}`. |
| /// |
| /// [debug_struct]: ../../std/fmt/struct.Formatter.html#method.debug_struct |
| /// |
| /// Pretty printing with `#?`: |
| /// |
| /// ``` |
| /// #[derive(Debug)] |
| /// struct Point { |
| /// x: i32, |
| /// y: i32, |
| /// } |
| /// |
| /// let origin = Point { x: 0, y: 0 }; |
| /// |
| /// println!("The origin is: {:#?}", origin); |
| /// ``` |
| /// |
| /// This outputs: |
| /// |
| /// ```text |
| /// The origin is: Point { |
| /// x: 0, |
| /// y: 0 |
| /// } |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[rustc_on_unimplemented = "`{Self}` cannot be formatted using `:?`; if it is \ |
| defined in your crate, add `#[derive(Debug)]` or \ |
| manually implement it"] |
| #[lang = "debug_trait"] |
| pub trait Debug { |
| /// Formats the value using the given formatter. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn fmt(&self, &mut Formatter) -> Result; |
| } |
| |
| /// Format trait for an empty format, `{}`. |
| /// |
| /// `Display` is similar to [`Debug`][debug], but `Display` is for user-facing |
| /// output, and so cannot be derived. |
| /// |
| /// [debug]: trait.Debug.html |
| /// |
| /// For more information on formatters, see [the module-level documentation][module]. |
| /// |
| /// [module]: ../../std/fmt/index.html |
| /// |
| /// # Examples |
| /// |
| /// Implementing `Display` on a type: |
| /// |
| /// ``` |
| /// use std::fmt; |
| /// |
| /// struct Point { |
| /// x: i32, |
| /// y: i32, |
| /// } |
| /// |
| /// impl fmt::Display for Point { |
| /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| /// write!(f, "({}, {})", self.x, self.y) |
| /// } |
| /// } |
| /// |
| /// let origin = Point { x: 0, y: 0 }; |
| /// |
| /// println!("The origin is: {}", origin); |
| /// ``` |
| #[rustc_on_unimplemented = "`{Self}` cannot be formatted with the default \ |
| formatter; try using `:?` instead if you are using \ |
| a format string"] |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub trait Display { |
| /// Formats the value using the given formatter. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn fmt(&self, &mut Formatter) -> Result; |
| } |
| |
| /// Format trait for the `o` character. |
| /// |
| /// The `Octal` trait should format its output as a number in base-8. |
| /// |
| /// The alternate flag, `#`, adds a `0o` in front of the output. |
| /// |
| /// For more information on formatters, see [the module-level documentation][module]. |
| /// |
| /// [module]: ../../std/fmt/index.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage with `i32`: |
| /// |
| /// ``` |
| /// let x = 42; // 42 is '52' in octal |
| /// |
| /// assert_eq!(format!("{:o}", x), "52"); |
| /// assert_eq!(format!("{:#o}", x), "0o52"); |
| /// ``` |
| /// |
| /// Implementing `Octal` on a type: |
| /// |
| /// ``` |
| /// use std::fmt; |
| /// |
| /// struct Length(i32); |
| /// |
| /// impl fmt::Octal for Length { |
| /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| /// let val = self.0; |
| /// |
| /// write!(f, "{:o}", val) // delegate to i32's implementation |
| /// } |
| /// } |
| /// |
| /// let l = Length(9); |
| /// |
| /// println!("l as octal is: {:o}", l); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub trait Octal { |
| /// Formats the value using the given formatter. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn fmt(&self, &mut Formatter) -> Result; |
| } |
| |
| /// Format trait for the `b` character. |
| /// |
| /// The `Binary` trait should format its output as a number in binary. |
| /// |
| /// The alternate flag, `#`, adds a `0b` in front of the output. |
| /// |
| /// For more information on formatters, see [the module-level documentation][module]. |
| /// |
| /// [module]: ../../std/fmt/index.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage with `i32`: |
| /// |
| /// ``` |
| /// let x = 42; // 42 is '101010' in binary |
| /// |
| /// assert_eq!(format!("{:b}", x), "101010"); |
| /// assert_eq!(format!("{:#b}", x), "0b101010"); |
| /// ``` |
| /// |
| /// Implementing `Binary` on a type: |
| /// |
| /// ``` |
| /// use std::fmt; |
| /// |
| /// struct Length(i32); |
| /// |
| /// impl fmt::Binary for Length { |
| /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| /// let val = self.0; |
| /// |
| /// write!(f, "{:b}", val) // delegate to i32's implementation |
| /// } |
| /// } |
| /// |
| /// let l = Length(107); |
| /// |
| /// println!("l as binary is: {:b}", l); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub trait Binary { |
| /// Formats the value using the given formatter. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn fmt(&self, &mut Formatter) -> Result; |
| } |
| |
| /// Format trait for the `x` character. |
| /// |
| /// The `LowerHex` trait should format its output as a number in hexadecimal, with `a` through `f` |
| /// in lower case. |
| /// |
| /// The alternate flag, `#`, adds a `0x` in front of the output. |
| /// |
| /// For more information on formatters, see [the module-level documentation][module]. |
| /// |
| /// [module]: ../../std/fmt/index.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage with `i32`: |
| /// |
| /// ``` |
| /// let x = 42; // 42 is '2a' in hex |
| /// |
| /// assert_eq!(format!("{:x}", x), "2a"); |
| /// assert_eq!(format!("{:#x}", x), "0x2a"); |
| /// ``` |
| /// |
| /// Implementing `LowerHex` on a type: |
| /// |
| /// ``` |
| /// use std::fmt; |
| /// |
| /// struct Length(i32); |
| /// |
| /// impl fmt::LowerHex for Length { |
| /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| /// let val = self.0; |
| /// |
| /// write!(f, "{:x}", val) // delegate to i32's implementation |
| /// } |
| /// } |
| /// |
| /// let l = Length(9); |
| /// |
| /// println!("l as hex is: {:x}", l); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub trait LowerHex { |
| /// Formats the value using the given formatter. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn fmt(&self, &mut Formatter) -> Result; |
| } |
| |
| /// Format trait for the `X` character. |
| /// |
| /// The `UpperHex` trait should format its output as a number in hexadecimal, with `A` through `F` |
| /// in upper case. |
| /// |
| /// The alternate flag, `#`, adds a `0x` in front of the output. |
| /// |
| /// For more information on formatters, see [the module-level documentation][module]. |
| /// |
| /// [module]: ../../std/fmt/index.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage with `i32`: |
| /// |
| /// ``` |
| /// let x = 42; // 42 is '2A' in hex |
| /// |
| /// assert_eq!(format!("{:X}", x), "2A"); |
| /// assert_eq!(format!("{:#X}", x), "0x2A"); |
| /// ``` |
| /// |
| /// Implementing `UpperHex` on a type: |
| /// |
| /// ``` |
| /// use std::fmt; |
| /// |
| /// struct Length(i32); |
| /// |
| /// impl fmt::UpperHex for Length { |
| /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| /// let val = self.0; |
| /// |
| /// write!(f, "{:X}", val) // delegate to i32's implementation |
| /// } |
| /// } |
| /// |
| /// let l = Length(9); |
| /// |
| /// println!("l as hex is: {:X}", l); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub trait UpperHex { |
| /// Formats the value using the given formatter. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn fmt(&self, &mut Formatter) -> Result; |
| } |
| |
| /// Format trait for the `p` character. |
| /// |
| /// The `Pointer` trait should format its output as a memory location. This is commonly presented |
| /// as hexadecimal. |
| /// |
| /// For more information on formatters, see [the module-level documentation][module]. |
| /// |
| /// [module]: ../../std/fmt/index.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage with `&i32`: |
| /// |
| /// ``` |
| /// let x = &42; |
| /// |
| /// let address = format!("{:p}", x); // this produces something like '0x7f06092ac6d0' |
| /// ``` |
| /// |
| /// Implementing `Pointer` on a type: |
| /// |
| /// ``` |
| /// use std::fmt; |
| /// |
| /// struct Length(i32); |
| /// |
| /// impl fmt::Pointer for Length { |
| /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| /// // use `as` to convert to a `*const T`, which implements Pointer, which we can use |
| /// |
| /// write!(f, "{:p}", self as *const Length) |
| /// } |
| /// } |
| /// |
| /// let l = Length(42); |
| /// |
| /// println!("l is in memory here: {:p}", l); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub trait Pointer { |
| /// Formats the value using the given formatter. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn fmt(&self, &mut Formatter) -> Result; |
| } |
| |
| /// Format trait for the `e` character. |
| /// |
| /// The `LowerExp` trait should format its output in scientific notation with a lower-case `e`. |
| /// |
| /// For more information on formatters, see [the module-level documentation][module]. |
| /// |
| /// [module]: ../../std/fmt/index.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage with `i32`: |
| /// |
| /// ``` |
| /// let x = 42.0; // 42.0 is '4.2e1' in scientific notation |
| /// |
| /// assert_eq!(format!("{:e}", x), "4.2e1"); |
| /// ``` |
| /// |
| /// Implementing `LowerExp` on a type: |
| /// |
| /// ``` |
| /// use std::fmt; |
| /// |
| /// struct Length(i32); |
| /// |
| /// impl fmt::LowerExp for Length { |
| /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| /// let val = self.0; |
| /// write!(f, "{}e1", val / 10) |
| /// } |
| /// } |
| /// |
| /// let l = Length(100); |
| /// |
| /// println!("l in scientific notation is: {:e}", l); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub trait LowerExp { |
| /// Formats the value using the given formatter. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn fmt(&self, &mut Formatter) -> Result; |
| } |
| |
| /// Format trait for the `E` character. |
| /// |
| /// The `UpperExp` trait should format its output in scientific notation with an upper-case `E`. |
| /// |
| /// For more information on formatters, see [the module-level documentation][module]. |
| /// |
| /// [module]: ../../std/fmt/index.html |
| /// |
| /// # Examples |
| /// |
| /// Basic usage with `f32`: |
| /// |
| /// ``` |
| /// let x = 42.0; // 42.0 is '4.2E1' in scientific notation |
| /// |
| /// assert_eq!(format!("{:E}", x), "4.2E1"); |
| /// ``` |
| /// |
| /// Implementing `UpperExp` on a type: |
| /// |
| /// ``` |
| /// use std::fmt; |
| /// |
| /// struct Length(i32); |
| /// |
| /// impl fmt::UpperExp for Length { |
| /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| /// let val = self.0; |
| /// write!(f, "{}E1", val / 10) |
| /// } |
| /// } |
| /// |
| /// let l = Length(100); |
| /// |
| /// println!("l in scientific notation is: {:E}", l); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub trait UpperExp { |
| /// Formats the value using the given formatter. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| fn fmt(&self, &mut Formatter) -> Result; |
| } |
| |
| /// The `write` function takes an output stream, a precompiled format string, |
| /// and a list of arguments. The arguments will be formatted according to the |
| /// specified format string into the output stream provided. |
| /// |
| /// # Arguments |
| /// |
| /// * output - the buffer to write output to |
| /// * args - the precompiled arguments generated by `format_args!` |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// use std::fmt; |
| /// |
| /// let mut output = String::new(); |
| /// fmt::write(&mut output, format_args!("Hello {}!", "world")) |
| /// .expect("Error occurred while trying to write in String"); |
| /// assert_eq!(output, "Hello world!"); |
| /// ``` |
| /// |
| /// Please note that using [`write!`][write_macro] might be preferrable. Example: |
| /// |
| /// ``` |
| /// use std::fmt::Write; |
| /// |
| /// let mut output = String::new(); |
| /// write!(&mut output, "Hello {}!", "world") |
| /// .expect("Error occurred while trying to write in String"); |
| /// assert_eq!(output, "Hello world!"); |
| /// ``` |
| /// |
| /// [write_macro]: ../../std/macro.write!.html |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn write(output: &mut Write, args: Arguments) -> Result { |
| let mut formatter = Formatter { |
| flags: 0, |
| width: None, |
| precision: None, |
| buf: output, |
| align: rt::v1::Alignment::Unknown, |
| fill: ' ', |
| args: args.args, |
| curarg: args.args.iter(), |
| }; |
| |
| let mut pieces = args.pieces.iter(); |
| |
| match args.fmt { |
| None => { |
| // We can use default formatting parameters for all arguments. |
| for (arg, piece) in args.args.iter().zip(pieces.by_ref()) { |
| formatter.buf.write_str(*piece)?; |
| (arg.formatter)(arg.value, &mut formatter)?; |
| } |
| } |
| Some(fmt) => { |
| // Every spec has a corresponding argument that is preceded by |
| // a string piece. |
| for (arg, piece) in fmt.iter().zip(pieces.by_ref()) { |
| formatter.buf.write_str(*piece)?; |
| formatter.run(arg)?; |
| } |
| } |
| } |
| |
| // There can be only one trailing string piece left. |
| if let Some(piece) = pieces.next() { |
| formatter.buf.write_str(*piece)?; |
| } |
| |
| Ok(()) |
| } |
| |
| impl<'a> Formatter<'a> { |
| |
| // First up is the collection of functions used to execute a format string |
| // at runtime. This consumes all of the compile-time statics generated by |
| // the format! syntax extension. |
| fn run(&mut self, arg: &rt::v1::Argument) -> Result { |
| // Fill in the format parameters into the formatter |
| self.fill = arg.format.fill; |
| self.align = arg.format.align; |
| self.flags = arg.format.flags; |
| self.width = self.getcount(&arg.format.width); |
| self.precision = self.getcount(&arg.format.precision); |
| |
| // Extract the correct argument |
| let value = match arg.position { |
| rt::v1::Position::Next => { *self.curarg.next().unwrap() } |
| rt::v1::Position::At(i) => self.args[i], |
| }; |
| |
| // Then actually do some printing |
| (value.formatter)(value.value, self) |
| } |
| |
| fn getcount(&mut self, cnt: &rt::v1::Count) -> Option<usize> { |
| match *cnt { |
| rt::v1::Count::Is(n) => Some(n), |
| rt::v1::Count::Implied => None, |
| rt::v1::Count::Param(i) => { |
| self.args[i].as_usize() |
| } |
| rt::v1::Count::NextParam => { |
| self.curarg.next().and_then(|arg| arg.as_usize()) |
| } |
| } |
| } |
| |
| // Helper methods used for padding and processing formatting arguments that |
| // all formatting traits can use. |
| |
| /// Performs the correct padding for an integer which has already been |
| /// emitted into a str. The str should *not* contain the sign for the |
| /// integer, that will be added by this method. |
| /// |
| /// # Arguments |
| /// |
| /// * is_nonnegative - whether the original integer was either positive or zero. |
| /// * prefix - if the '#' character (Alternate) is provided, this |
| /// is the prefix to put in front of the number. |
| /// * buf - the byte array that the number has been formatted into |
| /// |
| /// This function will correctly account for the flags provided as well as |
| /// the minimum width. It will not take precision into account. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn pad_integral(&mut self, |
| is_nonnegative: bool, |
| prefix: &str, |
| buf: &str) |
| -> Result { |
| use char::CharExt; |
| |
| let mut width = buf.len(); |
| |
| let mut sign = None; |
| if !is_nonnegative { |
| sign = Some('-'); width += 1; |
| } else if self.sign_plus() { |
| sign = Some('+'); width += 1; |
| } |
| |
| let mut prefixed = false; |
| if self.alternate() { |
| prefixed = true; width += prefix.chars().count(); |
| } |
| |
| // Writes the sign if it exists, and then the prefix if it was requested |
| let write_prefix = |f: &mut Formatter| { |
| if let Some(c) = sign { |
| f.buf.write_str(unsafe { |
| str::from_utf8_unchecked(c.encode_utf8().as_slice()) |
| })?; |
| } |
| if prefixed { f.buf.write_str(prefix) } |
| else { Ok(()) } |
| }; |
| |
| // The `width` field is more of a `min-width` parameter at this point. |
| match self.width { |
| // If there's no minimum length requirements then we can just |
| // write the bytes. |
| None => { |
| write_prefix(self)?; self.buf.write_str(buf) |
| } |
| // Check if we're over the minimum width, if so then we can also |
| // just write the bytes. |
| Some(min) if width >= min => { |
| write_prefix(self)?; self.buf.write_str(buf) |
| } |
| // The sign and prefix goes before the padding if the fill character |
| // is zero |
| Some(min) if self.sign_aware_zero_pad() => { |
| self.fill = '0'; |
| write_prefix(self)?; |
| self.with_padding(min - width, rt::v1::Alignment::Right, |f| { |
| f.buf.write_str(buf) |
| }) |
| } |
| // Otherwise, the sign and prefix goes after the padding |
| Some(min) => { |
| self.with_padding(min - width, rt::v1::Alignment::Right, |f| { |
| write_prefix(f)?; f.buf.write_str(buf) |
| }) |
| } |
| } |
| } |
| |
| /// This function takes a string slice and emits it to the internal buffer |
| /// after applying the relevant formatting flags specified. The flags |
| /// recognized for generic strings are: |
| /// |
| /// * width - the minimum width of what to emit |
| /// * fill/align - what to emit and where to emit it if the string |
| /// provided needs to be padded |
| /// * precision - the maximum length to emit, the string is truncated if it |
| /// is longer than this length |
| /// |
| /// Notably this function ignored the `flag` parameters |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn pad(&mut self, s: &str) -> Result { |
| // Make sure there's a fast path up front |
| if self.width.is_none() && self.precision.is_none() { |
| return self.buf.write_str(s); |
| } |
| // The `precision` field can be interpreted as a `max-width` for the |
| // string being formatted. |
| let s = if let Some(max) = self.precision { |
| // If our string is longer that the precision, then we must have |
| // truncation. However other flags like `fill`, `width` and `align` |
| // must act as always. |
| if let Some((i, _)) = s.char_indices().skip(max).next() { |
| &s[..i] |
| } else { |
| &s |
| } |
| } else { |
| &s |
| }; |
| // The `width` field is more of a `min-width` parameter at this point. |
| match self.width { |
| // If we're under the maximum length, and there's no minimum length |
| // requirements, then we can just emit the string |
| None => self.buf.write_str(s), |
| // If we're under the maximum width, check if we're over the minimum |
| // width, if so it's as easy as just emitting the string. |
| Some(width) if s.chars().count() >= width => { |
| self.buf.write_str(s) |
| } |
| // If we're under both the maximum and the minimum width, then fill |
| // up the minimum width with the specified string + some alignment. |
| Some(width) => { |
| let align = rt::v1::Alignment::Left; |
| self.with_padding(width - s.chars().count(), align, |me| { |
| me.buf.write_str(s) |
| }) |
| } |
| } |
| } |
| |
| /// Runs a callback, emitting the correct padding either before or |
| /// afterwards depending on whether right or left alignment is requested. |
| fn with_padding<F>(&mut self, padding: usize, default: rt::v1::Alignment, |
| f: F) -> Result |
| where F: FnOnce(&mut Formatter) -> Result, |
| { |
| use char::CharExt; |
| let align = match self.align { |
| rt::v1::Alignment::Unknown => default, |
| _ => self.align |
| }; |
| |
| let (pre_pad, post_pad) = match align { |
| rt::v1::Alignment::Left => (0, padding), |
| rt::v1::Alignment::Right | |
| rt::v1::Alignment::Unknown => (padding, 0), |
| rt::v1::Alignment::Center => (padding / 2, (padding + 1) / 2), |
| }; |
| |
| let fill = self.fill.encode_utf8(); |
| let fill = unsafe { |
| str::from_utf8_unchecked(fill.as_slice()) |
| }; |
| |
| for _ in 0..pre_pad { |
| self.buf.write_str(fill)?; |
| } |
| |
| f(self)?; |
| |
| for _ in 0..post_pad { |
| self.buf.write_str(fill)?; |
| } |
| |
| Ok(()) |
| } |
| |
| /// Takes the formatted parts and applies the padding. |
| /// Assumes that the caller already has rendered the parts with required precision, |
| /// so that `self.precision` can be ignored. |
| fn pad_formatted_parts(&mut self, formatted: &flt2dec::Formatted) -> Result { |
| if let Some(mut width) = self.width { |
| // for the sign-aware zero padding, we render the sign first and |
| // behave as if we had no sign from the beginning. |
| let mut formatted = formatted.clone(); |
| let mut align = self.align; |
| let old_fill = self.fill; |
| if self.sign_aware_zero_pad() { |
| // a sign always goes first |
| let sign = unsafe { str::from_utf8_unchecked(formatted.sign) }; |
| self.buf.write_str(sign)?; |
| |
| // remove the sign from the formatted parts |
| formatted.sign = b""; |
| width = if width < sign.len() { 0 } else { width - sign.len() }; |
| align = rt::v1::Alignment::Right; |
| self.fill = '0'; |
| } |
| |
| // remaining parts go through the ordinary padding process. |
| let len = formatted.len(); |
| let ret = if width <= len { // no padding |
| self.write_formatted_parts(&formatted) |
| } else { |
| self.with_padding(width - len, align, |f| { |
| f.write_formatted_parts(&formatted) |
| }) |
| }; |
| self.fill = old_fill; |
| ret |
| } else { |
| // this is the common case and we take a shortcut |
| self.write_formatted_parts(formatted) |
| } |
| } |
| |
| fn write_formatted_parts(&mut self, formatted: &flt2dec::Formatted) -> Result { |
| fn write_bytes(buf: &mut Write, s: &[u8]) -> Result { |
| buf.write_str(unsafe { str::from_utf8_unchecked(s) }) |
| } |
| |
| if !formatted.sign.is_empty() { |
| write_bytes(self.buf, formatted.sign)?; |
| } |
| for part in formatted.parts { |
| match *part { |
| flt2dec::Part::Zero(mut nzeroes) => { |
| const ZEROES: &'static str = // 64 zeroes |
| "0000000000000000000000000000000000000000000000000000000000000000"; |
| while nzeroes > ZEROES.len() { |
| self.buf.write_str(ZEROES)?; |
| nzeroes -= ZEROES.len(); |
| } |
| if nzeroes > 0 { |
| self.buf.write_str(&ZEROES[..nzeroes])?; |
| } |
| } |
| flt2dec::Part::Num(mut v) => { |
| let mut s = [0; 5]; |
| let len = part.len(); |
| for c in s[..len].iter_mut().rev() { |
| *c = b'0' + (v % 10) as u8; |
| v /= 10; |
| } |
| write_bytes(self.buf, &s[..len])?; |
| } |
| flt2dec::Part::Copy(buf) => { |
| write_bytes(self.buf, buf)?; |
| } |
| } |
| } |
| Ok(()) |
| } |
| |
| /// Writes some data to the underlying buffer contained within this |
| /// formatter. |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn write_str(&mut self, data: &str) -> Result { |
| self.buf.write_str(data) |
| } |
| |
| /// Writes some formatted information into this instance |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn write_fmt(&mut self, fmt: Arguments) -> Result { |
| write(self.buf, fmt) |
| } |
| |
| /// Flags for formatting (packed version of rt::Flag) |
| #[stable(feature = "rust1", since = "1.0.0")] |
| pub fn flags(&self) -> u32 { self.flags } |
| |
| /// Character used as 'fill' whenever there is alignment |
| #[stable(feature = "fmt_flags", since = "1.5.0")] |
| pub fn fill(&self) -> char { self.fill } |
| |
| /// Flag indicating what form of alignment was requested |
| #[unstable(feature = "fmt_flags_align", reason = "method was just created", |
| issue = "27726")] |
| pub fn align(&self) -> Alignment { |
| match self.align { |
| rt::v1::Alignment::Left => Alignment::Left, |
| rt::v1::Alignment::Right => Alignment::Right, |
| rt::v1::Alignment::Center => Alignment::Center, |
| rt::v1::Alignment::Unknown => Alignment::Unknown, |
| } |
| } |
| |
| /// Optionally specified integer width that the output should be |
| #[stable(feature = "fmt_flags", since = "1.5.0")] |
| pub fn width(&self) -> Option<usize> { self.width } |
| |
| /// Optionally specified precision for numeric types |
| #[stable(feature = "fmt_flags", since = "1.5.0")] |
| pub fn precision(&self) -> Option<usize> { self.precision } |
| |
| /// Determines if the `+` flag was specified. |
| #[stable(feature = "fmt_flags", since = "1.5.0")] |
| pub fn sign_plus(&self) -> bool { self.flags & (1 << FlagV1::SignPlus as u32) != 0 } |
| |
| /// Determines if the `-` flag was specified. |
| #[stable(feature = "fmt_flags", since = "1.5.0")] |
| pub fn sign_minus(&self) -> bool { self.flags & (1 << FlagV1::SignMinus as u32) != 0 } |
| |
| /// Determines if the `#` flag was specified. |
| #[stable(feature = "fmt_flags", since = "1.5.0")] |
| pub fn alternate(&self) -> bool { self.flags & (1 << FlagV1::Alternate as u32) != 0 } |
| |
| /// Determines if the `0` flag was specified. |
| #[stable(feature = "fmt_flags", since = "1.5.0")] |
| pub fn sign_aware_zero_pad(&self) -> bool { |
| self.flags & (1 << FlagV1::SignAwareZeroPad as u32) != 0 |
| } |
| |
| /// Creates a `DebugStruct` builder designed to assist with creation of |
| /// `fmt::Debug` implementations for structs. |
| /// |
| /// # Examples |
| /// |
| /// ```rust |
| /// use std::fmt; |
| /// |
| /// struct Foo { |
| /// bar: i32, |
| /// baz: String, |
| /// } |
| /// |
| /// impl fmt::Debug for Foo { |
| /// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { |
| /// fmt.debug_struct("Foo") |
| /// .field("bar", &self.bar) |
| /// .field("baz", &self.baz) |
| /// .finish() |
| /// } |
| /// } |
| /// |
| /// // prints "Foo { bar: 10, baz: "Hello World" }" |
| /// println!("{:?}", Foo { bar: 10, baz: "Hello World".to_string() }); |
| /// ``` |
| #[stable(feature = "debug_builders", since = "1.2.0")] |
| #[inline] |
| pub fn debug_struct<'b>(&'b mut self, name: &str) -> DebugStruct<'b, 'a> { |
| builders::debug_struct_new(self, name) |
| } |
| |
| /// Creates a `DebugTuple` builder designed to assist with creation of |
| /// `fmt::Debug` implementations for tuple structs. |
| /// |
| /// # Examples |
| /// |
| /// ```rust |
| /// use std::fmt; |
| /// |
| /// struct Foo(i32, String); |
| /// |
| /// impl fmt::Debug for Foo { |
| /// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { |
| /// fmt.debug_tuple("Foo") |
| /// .field(&self.0) |
| /// .field(&self.1) |
| /// .finish() |
| /// } |
| /// } |
| /// |
| /// // prints "Foo(10, "Hello World")" |
| /// println!("{:?}", Foo(10, "Hello World".to_string())); |
| /// ``` |
| #[stable(feature = "debug_builders", since = "1.2.0")] |
| #[inline] |
| pub fn debug_tuple<'b>(&'b mut self, name: &str) -> DebugTuple<'b, 'a> { |
| builders::debug_tuple_new(self, name) |
| } |
| |
| /// Creates a `DebugList` builder designed to assist with creation of |
| /// `fmt::Debug` implementations for list-like structures. |
| /// |
| /// # Examples |
| /// |
| /// ```rust |
| /// use std::fmt; |
| /// |
| /// struct Foo(Vec<i32>); |
| /// |
| /// impl fmt::Debug for Foo { |
| /// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { |
| /// fmt.debug_list().entries(self.0.iter()).finish() |
| /// } |
| /// } |
| /// |
| /// // prints "[10, 11]" |
| /// println!("{:?}", Foo(vec![10, 11])); |
| /// ``` |
| #[stable(feature = "debug_builders", since = "1.2.0")] |
| #[inline] |
| pub fn debug_list<'b>(&'b mut self) -> DebugList<'b, 'a> { |
| builders::debug_list_new(self) |
| } |
| |
| /// Creates a `DebugSet` builder designed to assist with creation of |
| /// `fmt::Debug` implementations for set-like structures. |
| /// |
| /// # Examples |
| /// |
| /// ```rust |
| /// use std::fmt; |
| /// |
| /// struct Foo(Vec<i32>); |
| /// |
| /// impl fmt::Debug for Foo { |
| /// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { |
| /// fmt.debug_set().entries(self.0.iter()).finish() |
| /// } |
| /// } |
| /// |
| /// // prints "{10, 11}" |
| /// println!("{:?}", Foo(vec![10, 11])); |
| /// ``` |
| #[stable(feature = "debug_builders", since = "1.2.0")] |
| #[inline] |
| pub fn debug_set<'b>(&'b mut self) -> DebugSet<'b, 'a> { |
| builders::debug_set_new(self) |
| } |
| |
| /// Creates a `DebugMap` builder designed to assist with creation of |
| /// `fmt::Debug` implementations for map-like structures. |
| /// |
| /// # Examples |
| /// |
| /// ```rust |
| /// use std::fmt; |
| /// |
| /// struct Foo(Vec<(String, i32)>); |
| /// |
| /// impl fmt::Debug for Foo { |
| /// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { |
| /// fmt.debug_map().entries(self.0.iter().map(|&(ref k, ref v)| (k, v))).finish() |
| /// } |
| /// } |
| /// |
| /// // prints "{"A": 10, "B": 11}" |
| /// println!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])); |
| /// ``` |
| #[stable(feature = "debug_builders", since = "1.2.0")] |
| #[inline] |
| pub fn debug_map<'b>(&'b mut self) -> DebugMap<'b, 'a> { |
| builders::debug_map_new(self) |
| } |
| } |
| |
| #[stable(since = "1.2.0", feature = "formatter_write")] |
| impl<'a> Write for Formatter<'a> { |
| fn write_str(&mut self, s: &str) -> Result { |
| self.buf.write_str(s) |
| } |
| |
| fn write_char(&mut self, c: char) -> Result { |
| self.buf.write_char(c) |
| } |
| |
| fn write_fmt(&mut self, args: Arguments) -> Result { |
| write(self.buf, args) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Display for Error { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| Display::fmt("an error occurred when formatting an argument", f) |
| } |
| } |
| |
| // Implementations of the core formatting traits |
| |
| macro_rules! fmt_refs { |
| ($($tr:ident),*) => { |
| $( |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T: ?Sized + $tr> $tr for &'a T { |
| fn fmt(&self, f: &mut Formatter) -> Result { $tr::fmt(&**self, f) } |
| } |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T: ?Sized + $tr> $tr for &'a mut T { |
| fn fmt(&self, f: &mut Formatter) -> Result { $tr::fmt(&**self, f) } |
| } |
| )* |
| } |
| } |
| |
| fmt_refs! { Debug, Display, Octal, Binary, LowerHex, UpperHex, LowerExp, UpperExp } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Debug for bool { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| Display::fmt(self, f) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Display for bool { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| Display::fmt(if *self { "true" } else { "false" }, f) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Debug for str { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| f.write_char('"')?; |
| let mut from = 0; |
| for (i, c) in self.char_indices() { |
| let esc = c.escape_debug(); |
| // If char needs escaping, flush backlog so far and write, else skip |
| if esc.len() != 1 { |
| f.write_str(&self[from..i])?; |
| for c in esc { |
| f.write_char(c)?; |
| } |
| from = i + c.len_utf8(); |
| } |
| } |
| f.write_str(&self[from..])?; |
| f.write_char('"') |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Display for str { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| f.pad(self) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Debug for char { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| f.write_char('\'')?; |
| for c in self.escape_debug() { |
| f.write_char(c)? |
| } |
| f.write_char('\'') |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Display for char { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| if f.width.is_none() && f.precision.is_none() { |
| f.write_char(*self) |
| } else { |
| f.pad(unsafe { |
| str::from_utf8_unchecked(self.encode_utf8().as_slice()) |
| }) |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized> Pointer for *const T { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| let old_width = f.width; |
| let old_flags = f.flags; |
| |
| // The alternate flag is already treated by LowerHex as being special- |
| // it denotes whether to prefix with 0x. We use it to work out whether |
| // or not to zero extend, and then unconditionally set it to get the |
| // prefix. |
| if f.alternate() { |
| f.flags |= 1 << (FlagV1::SignAwareZeroPad as u32); |
| |
| if let None = f.width { |
| f.width = Some(((mem::size_of::<usize>() * 8) / 4) + 2); |
| } |
| } |
| f.flags |= 1 << (FlagV1::Alternate as u32); |
| |
| let ret = LowerHex::fmt(&(*self as *const () as usize), f); |
| |
| f.width = old_width; |
| f.flags = old_flags; |
| |
| ret |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized> Pointer for *mut T { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| Pointer::fmt(&(*self as *const T), f) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T: ?Sized> Pointer for &'a T { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| Pointer::fmt(&(*self as *const T), f) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'a, T: ?Sized> Pointer for &'a mut T { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| Pointer::fmt(&(&**self as *const T), f) |
| } |
| } |
| |
| // Common code of floating point Debug and Display. |
| fn float_to_decimal_common<T>(fmt: &mut Formatter, num: &T, negative_zero: bool) -> Result |
| where T: flt2dec::DecodableFloat |
| { |
| let force_sign = fmt.sign_plus(); |
| let sign = match (force_sign, negative_zero) { |
| (false, false) => flt2dec::Sign::Minus, |
| (false, true) => flt2dec::Sign::MinusRaw, |
| (true, false) => flt2dec::Sign::MinusPlus, |
| (true, true) => flt2dec::Sign::MinusPlusRaw, |
| }; |
| |
| let mut buf = [0; 1024]; // enough for f32 and f64 |
| let mut parts = [flt2dec::Part::Zero(0); 16]; |
| let formatted = if let Some(precision) = fmt.precision { |
| flt2dec::to_exact_fixed_str(flt2dec::strategy::grisu::format_exact, *num, sign, |
| precision, false, &mut buf, &mut parts) |
| } else { |
| flt2dec::to_shortest_str(flt2dec::strategy::grisu::format_shortest, *num, sign, |
| 0, false, &mut buf, &mut parts) |
| }; |
| fmt.pad_formatted_parts(&formatted) |
| } |
| |
| // Common code of floating point LowerExp and UpperExp. |
| fn float_to_exponential_common<T>(fmt: &mut Formatter, num: &T, upper: bool) -> Result |
| where T: flt2dec::DecodableFloat |
| { |
| let force_sign = fmt.sign_plus(); |
| let sign = match force_sign { |
| false => flt2dec::Sign::Minus, |
| true => flt2dec::Sign::MinusPlus, |
| }; |
| |
| let mut buf = [0; 1024]; // enough for f32 and f64 |
| let mut parts = [flt2dec::Part::Zero(0); 16]; |
| let formatted = if let Some(precision) = fmt.precision { |
| // 1 integral digit + `precision` fractional digits = `precision + 1` total digits |
| flt2dec::to_exact_exp_str(flt2dec::strategy::grisu::format_exact, *num, sign, |
| precision + 1, upper, &mut buf, &mut parts) |
| } else { |
| flt2dec::to_shortest_exp_str(flt2dec::strategy::grisu::format_shortest, *num, sign, |
| (0, 0), upper, &mut buf, &mut parts) |
| }; |
| fmt.pad_formatted_parts(&formatted) |
| } |
| |
| macro_rules! floating { ($ty:ident) => { |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Debug for $ty { |
| fn fmt(&self, fmt: &mut Formatter) -> Result { |
| float_to_decimal_common(fmt, self, true) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Display for $ty { |
| fn fmt(&self, fmt: &mut Formatter) -> Result { |
| float_to_decimal_common(fmt, self, false) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl LowerExp for $ty { |
| fn fmt(&self, fmt: &mut Formatter) -> Result { |
| float_to_exponential_common(fmt, self, false) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl UpperExp for $ty { |
| fn fmt(&self, fmt: &mut Formatter) -> Result { |
| float_to_exponential_common(fmt, self, true) |
| } |
| } |
| } } |
| floating! { f32 } |
| floating! { f64 } |
| |
| // Implementation of Display/Debug for various core types |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> Debug for *const T { |
| fn fmt(&self, f: &mut Formatter) -> Result { Pointer::fmt(self, f) } |
| } |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T> Debug for *mut T { |
| fn fmt(&self, f: &mut Formatter) -> Result { Pointer::fmt(self, f) } |
| } |
| |
| macro_rules! peel { |
| ($name:ident, $($other:ident,)*) => (tuple! { $($other,)* }) |
| } |
| |
| macro_rules! tuple { |
| () => (); |
| ( $($name:ident,)+ ) => ( |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<$($name:Debug),*> Debug for ($($name,)*) { |
| #[allow(non_snake_case, unused_assignments, deprecated)] |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| let mut builder = f.debug_tuple(""); |
| let ($(ref $name,)*) = *self; |
| $( |
| builder.field($name); |
| )* |
| |
| builder.finish() |
| } |
| } |
| peel! { $($name,)* } |
| ) |
| } |
| |
| tuple! { T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: Debug> Debug for [T] { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| f.debug_list().entries(self.iter()).finish() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl Debug for () { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| f.pad("()") |
| } |
| } |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized> Debug for PhantomData<T> { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| f.pad("PhantomData") |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: Copy + Debug> Debug for Cell<T> { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| f.debug_struct("Cell") |
| .field("value", &self.get()) |
| .finish() |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized + Debug> Debug for RefCell<T> { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| match self.borrow_state() { |
| BorrowState::Unused | BorrowState::Reading => { |
| f.debug_struct("RefCell") |
| .field("value", &self.borrow()) |
| .finish() |
| } |
| BorrowState::Writing => { |
| f.debug_struct("RefCell") |
| .field("value", &"<borrowed>") |
| .finish() |
| } |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'b, T: ?Sized + Debug> Debug for Ref<'b, T> { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| Debug::fmt(&**self, f) |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<'b, T: ?Sized + Debug> Debug for RefMut<'b, T> { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| Debug::fmt(&*(self.deref()), f) |
| } |
| } |
| |
| #[stable(feature = "core_impl_debug", since = "1.9.0")] |
| impl<T: ?Sized + Debug> Debug for UnsafeCell<T> { |
| fn fmt(&self, f: &mut Formatter) -> Result { |
| f.pad("UnsafeCell") |
| } |
| } |
| |
| // If you expected tests to be here, look instead at the run-pass/ifmt.rs test, |
| // it's a lot easier than creating all of the rt::Piece structures here. |
