From e63471f7a33133861b5c703ee1e3ec599bff9c16 Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Mon, 28 Aug 2023 20:59:37 +0000
Subject: [PATCH] Drop `memchr` dependency

While `memchr` has served us well, it finally bumped its MSRV
substantially such that its no longer really practical in a
particularly MSRV-constrained environment (e.g. when building on
machines with validated toolchains or Debian stable).

Luckily, its barely used, and not really worth retaining. A trivial
scan should be something LLVM can optimize at least somewhat
reasonably.
---
 Cargo.toml         | 1 -
 src/io/buffered.rs | 6 +++---
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 68e2fef..116541e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,7 +9,6 @@ repository = "https://github.com/bbqsrc/core2"
 categories = ["no-std"]
 
 [dependencies]
-memchr = { version = "2", default-features = false }
 
 [features]
 default = ["std"]
diff --git a/src/io/buffered.rs b/src/io/buffered.rs
index 4a03c93..f5cbca7 100644
--- a/src/io/buffered.rs
+++ b/src/io/buffered.rs
@@ -808,7 +808,7 @@ impl<'a, W: Write, const S: usize> Write for LineWriterShim<'a, W, S> {
     /// writer, it will also flush the existing buffer if it ends with a
     /// newline, even if the incoming data does not contain any newlines.
     fn write(&mut self, buf: &[u8]) -> Result<usize> {
-        let newline_idx = match memchr::memrchr(b'\n', buf) {
+        let newline_idx = match buf.iter().rev().position(|b| *b == b'\n') {
             // If there are no new newlines (that is, if this write is less than
             // one line), just do a regular buffered write (which may flush if
             // we exceed the inner buffer's size)
@@ -866,7 +866,7 @@ impl<'a, W: Write, const S: usize> Write for LineWriterShim<'a, W, S> {
         } else {
             let scan_area = &buf[flushed..];
             let scan_area = &scan_area[..self.buffer.capacity()];
-            match memchr::memrchr(b'\n', scan_area) {
+            match scan_area.iter().rev().position(|b| *b == b'\n') {
                 Some(newline_idx) => &scan_area[..newline_idx + 1],
                 None => scan_area,
             }
@@ -889,7 +889,7 @@ impl<'a, W: Write, const S: usize> Write for LineWriterShim<'a, W, S> {
     /// writer, it will also flush the existing buffer if it contains any
     /// newlines, even if the incoming data does not contain any newlines.
     fn write_all(&mut self, buf: &[u8]) -> Result<()> {
-        match memchr::memrchr(b'\n', buf) {
+        match buf.iter().rev().position(|b| *b == b'\n') {
             // If there are no new newlines (that is, if this write is less than
             // one line), just do a regular buffered write (which may flush if
             // we exceed the inner buffer's size)