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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
commit36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/ryu/src/buffer/mod.rs
parentInitial commit. (diff)
downloadfirefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz
firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/ryu/src/buffer/mod.rs')
-rw-r--r--third_party/rust/ryu/src/buffer/mod.rs170
1 files changed, 170 insertions, 0 deletions
diff --git a/third_party/rust/ryu/src/buffer/mod.rs b/third_party/rust/ryu/src/buffer/mod.rs
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+use crate::raw;
+use core::mem::MaybeUninit;
+use core::{slice, str};
+#[cfg(feature = "no-panic")]
+use no_panic::no_panic;
+
+const NAN: &str = "NaN";
+const INFINITY: &str = "inf";
+const NEG_INFINITY: &str = "-inf";
+
+/// Safe API for formatting floating point numbers to text.
+///
+/// ## Example
+///
+/// ```
+/// let mut buffer = ryu::Buffer::new();
+/// let printed = buffer.format_finite(1.234);
+/// assert_eq!(printed, "1.234");
+/// ```
+pub struct Buffer {
+ bytes: [MaybeUninit<u8>; 24],
+}
+
+impl Buffer {
+ /// This is a cheap operation; you don't need to worry about reusing buffers
+ /// for efficiency.
+ #[inline]
+ #[cfg_attr(feature = "no-panic", no_panic)]
+ pub fn new() -> Self {
+ let bytes = [MaybeUninit::<u8>::uninit(); 24];
+ Buffer { bytes }
+ }
+
+ /// Print a floating point number into this buffer and return a reference to
+ /// its string representation within the buffer.
+ ///
+ /// # Special cases
+ ///
+ /// This function formats NaN as the string "NaN", positive infinity as
+ /// "inf", and negative infinity as "-inf" to match std::fmt.
+ ///
+ /// If your input is known to be finite, you may get better performance by
+ /// calling the `format_finite` method instead of `format` to avoid the
+ /// checks for special cases.
+ #[cfg_attr(feature = "no-panic", inline)]
+ #[cfg_attr(feature = "no-panic", no_panic)]
+ pub fn format<F: Float>(&mut self, f: F) -> &str {
+ if f.is_nonfinite() {
+ f.format_nonfinite()
+ } else {
+ self.format_finite(f)
+ }
+ }
+
+ /// Print a floating point number into this buffer and return a reference to
+ /// its string representation within the buffer.
+ ///
+ /// # Special cases
+ ///
+ /// This function **does not** check for NaN or infinity. If the input
+ /// number is not a finite float, the printed representation will be some
+ /// correctly formatted but unspecified numerical value.
+ ///
+ /// Please check [`is_finite`] yourself before calling this function, or
+ /// check [`is_nan`] and [`is_infinite`] and handle those cases yourself.
+ ///
+ /// [`is_finite`]: https://doc.rust-lang.org/std/primitive.f64.html#method.is_finite
+ /// [`is_nan`]: https://doc.rust-lang.org/std/primitive.f64.html#method.is_nan
+ /// [`is_infinite`]: https://doc.rust-lang.org/std/primitive.f64.html#method.is_infinite
+ #[inline]
+ #[cfg_attr(feature = "no-panic", no_panic)]
+ pub fn format_finite<F: Float>(&mut self, f: F) -> &str {
+ unsafe {
+ let n = f.write_to_ryu_buffer(self.bytes.as_mut_ptr() as *mut u8);
+ debug_assert!(n <= self.bytes.len());
+ let slice = slice::from_raw_parts(self.bytes.as_ptr() as *const u8, n);
+ str::from_utf8_unchecked(slice)
+ }
+ }
+}
+
+impl Copy for Buffer {}
+
+impl Clone for Buffer {
+ #[inline]
+ fn clone(&self) -> Self {
+ Buffer::new()
+ }
+}
+
+impl Default for Buffer {
+ #[inline]
+ #[cfg_attr(feature = "no-panic", no_panic)]
+ fn default() -> Self {
+ Buffer::new()
+ }
+}
+
+/// A floating point number, f32 or f64, that can be written into a
+/// [`ryu::Buffer`][Buffer].
+///
+/// This trait is sealed and cannot be implemented for types outside of the
+/// `ryu` crate.
+pub trait Float: Sealed {}
+impl Float for f32 {}
+impl Float for f64 {}
+
+pub trait Sealed: Copy {
+ fn is_nonfinite(self) -> bool;
+ fn format_nonfinite(self) -> &'static str;
+ unsafe fn write_to_ryu_buffer(self, result: *mut u8) -> usize;
+}
+
+impl Sealed for f32 {
+ #[inline]
+ fn is_nonfinite(self) -> bool {
+ const EXP_MASK: u32 = 0x7f800000;
+ let bits = self.to_bits();
+ bits & EXP_MASK == EXP_MASK
+ }
+
+ #[cold]
+ #[cfg_attr(feature = "no-panic", inline)]
+ fn format_nonfinite(self) -> &'static str {
+ const MANTISSA_MASK: u32 = 0x007fffff;
+ const SIGN_MASK: u32 = 0x80000000;
+ let bits = self.to_bits();
+ if bits & MANTISSA_MASK != 0 {
+ NAN
+ } else if bits & SIGN_MASK != 0 {
+ NEG_INFINITY
+ } else {
+ INFINITY
+ }
+ }
+
+ #[inline]
+ unsafe fn write_to_ryu_buffer(self, result: *mut u8) -> usize {
+ raw::format32(self, result)
+ }
+}
+
+impl Sealed for f64 {
+ #[inline]
+ fn is_nonfinite(self) -> bool {
+ const EXP_MASK: u64 = 0x7ff0000000000000;
+ let bits = self.to_bits();
+ bits & EXP_MASK == EXP_MASK
+ }
+
+ #[cold]
+ #[cfg_attr(feature = "no-panic", inline)]
+ fn format_nonfinite(self) -> &'static str {
+ const MANTISSA_MASK: u64 = 0x000fffffffffffff;
+ const SIGN_MASK: u64 = 0x8000000000000000;
+ let bits = self.to_bits();
+ if bits & MANTISSA_MASK != 0 {
+ NAN
+ } else if bits & SIGN_MASK != 0 {
+ NEG_INFINITY
+ } else {
+ INFINITY
+ }
+ }
+
+ #[inline]
+ unsafe fn write_to_ryu_buffer(self, result: *mut u8) -> usize {
+ raw::format64(self, result)
+ }
+}