From d318878c5fb164a29bbd7c12dafd564dfec16c8b Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Wed, 20 Nov 2024 14:31:27 +0100
Subject: [PATCH] Reduce integer `Display` implementation size
---
library/core/src/fmt/num.rs | 96 ++++++++++++++++++-------------------
1 file changed, 48 insertions(+), 48 deletions(-)
diff --git a/library/core/src/fmt/num.rs b/library/core/src/fmt/num.rs
index f2d7e0f481e..01b5d46a8f6 100644
--- a/library/core/src/fmt/num.rs
+++ b/library/core/src/fmt/num.rs
@@ -199,32 +199,12 @@ static DEC_DIGITS_LUT: &[u8; 200] = b"0001020304050607080910111213141516171819\
8081828384858687888990919293949596979899";
macro_rules! impl_Display {
- ($($t:ident $(as $positive:ident)? named $name:ident,)* ; as $u:ident via $conv_fn:ident named $gen_name:ident) => {
+ ($($signed:ident, $unsigned:ident,)* ; as $u:ident via $conv_fn:ident named $gen_name:ident) => {
$(
#[stable(feature = "rust1", since = "1.0.0")]
- impl fmt::Display for $t {
+ impl fmt::Display for $unsigned {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- // If it's a signed integer.
- $(
- let is_nonnegative = *self >= 0;
-
- #[cfg(not(feature = "optimize_for_size"))]
- {
- if !is_nonnegative {
- // convert the negative num to positive by summing 1 to its 2s complement
- return (!self as $positive).wrapping_add(1)._fmt(false, f);
- }
- }
- #[cfg(feature = "optimize_for_size")]
- {
- if !is_nonnegative {
- // convert the negative num to positive by summing 1 to its 2s complement
- return $gen_name((!self.$conv_fn()).wrapping_add(1), false, f);
- }
- }
- )?
- // If it's a positive integer.
#[cfg(not(feature = "optimize_for_size"))]
{
self._fmt(true, f)
@@ -236,10 +216,40 @@ macro_rules! impl_Display {
}
}
+ #[stable(feature = "rust1", since = "1.0.0")]
+ impl fmt::Display for $signed {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ let is_nonnegative = *self >= 0;
+
+ if !is_nonnegative {
+ #[cfg(not(feature = "optimize_for_size"))]
+ {
+ // convert the negative num to positive by summing 1 to its 2s complement
+ return (!self as $unsigned).wrapping_add(1)._fmt(false, f);
+ }
+ #[cfg(feature = "optimize_for_size")]
+ {
+ // convert the negative num to positive by summing 1 to its 2s complement
+ return $gen_name((!self.$conv_fn()).wrapping_add(1), false, f);
+ }
+ }
+
+ // If it's a positive integer.
+ #[cfg(not(feature = "optimize_for_size"))]
+ {
+ (*self as $unsigned)._fmt(true, f)
+ }
+ #[cfg(feature = "optimize_for_size")]
+ {
+ $gen_name(self.$conv_fn(), true, f)
+ }
+ }
+ }
+
#[cfg(not(feature = "optimize_for_size"))]
- impl $t {
- fn _fmt(mut self: $t, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- const SIZE: usize = $t::MAX.ilog(10) as usize + 1;
+ impl $unsigned {
+ fn _fmt(mut self, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ const SIZE: usize = $unsigned::MAX.ilog(10) as usize + 1;
let mut buf = [MaybeUninit::<u8>::uninit(); SIZE];
let mut curr = SIZE;
let buf_ptr = MaybeUninit::slice_as_mut_ptr(&mut buf);
@@ -258,7 +268,7 @@ macro_rules! impl_Display {
#[allow(unused_comparisons)]
// This block will be removed for smaller types at compile time and in the worst
// case, it will prevent to have the `10000` literal to overflow for `i8` and `u8`.
- if core::mem::size_of::<$t>() >= 2 {
+ if core::mem::size_of::<$unsigned>() >= 2 {
// eagerly decode 4 characters at a time
while self >= 10000 {
let rem = (self % 10000) as usize;
@@ -312,8 +322,8 @@ macro_rules! impl_Display {
#[cfg(feature = "optimize_for_size")]
fn $gen_name(mut n: $u, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- // 2^128 is about 3*10^38, so 39 gives an extra byte of space
- let mut buf = [MaybeUninit::<u8>::uninit(); 39];
+ const SIZE: usize = $u::MAX.ilog(10) as usize + 1;
+ let mut buf = [MaybeUninit::<u8>::uninit(); SIZE];
let mut curr = buf.len();
let buf_ptr = MaybeUninit::slice_as_mut_ptr(&mut buf);
@@ -523,16 +533,11 @@ impl_Debug! {
mod imp {
use super::*;
impl_Display!(
- i8 as u8 named fmt_i8,
- u8 named fmt_u8,
- i16 as u16 named fmt_i16,
- u16 named fmt_u16,
- i32 as u32 named fmt_i32,
- u32 named fmt_u32,
- i64 as u64 named fmt_i64,
- u64 named fmt_u64,
- isize as usize named fmt_isize,
- usize named fmt_usize,
+ i8, u8,
+ i16, u16,
+ i32, u32,
+ i64, u64,
+ isize, usize,
; as u64 via to_u64 named fmt_u64
);
impl_Exp!(
@@ -545,18 +550,13 @@ mod imp {
mod imp {
use super::*;
impl_Display!(
- i8 as u8 named fmt_i8,
- u8 named fmt_u8,
- i16 as u16 named fmt_i16,
- u16 named fmt_u16,
- i32 as u32 named fmt_i32,
- u32 named fmt_u32,
- isize as usize named fmt_isize,
- usize named fmt_usize,
+ i8, u8,
+ i16, u16,
+ i32, u32,
+ isize, usize,
; as u32 via to_u32 named fmt_u32);
impl_Display!(
- i64 as u64 named fmt_i64,
- u64 named fmt_u64,
+ i64, u64,
; as u64 via to_u64 named fmt_u64);
impl_Exp!(i8, u8, i16, u16, i32, u32, isize, usize as u32 via to_u32 named exp_u32);