From 2e4896cc7ca45ddba63301de73c377bdf9db1d50 Mon Sep 17 00:00:00 2001
From: Frank Denis <github@pureftpd.org>
Date: Wed, 23 Aug 2023 10:52:04 +0200
Subject: [PATCH] Revert "Hasher::write_u*() are expected keep the native
 endianness"

This reverts commit e5264daafb255555180ce2db42343d5f617d55f8.
---
 src/sip.rs    | 12 +++++++++---
 src/sip128.rs | 12 +++++++++---
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/sip.rs b/src/sip.rs
index 4ce2c1f..2e1e307 100644
--- a/src/sip.rs
+++ b/src/sip.rs
@@ -296,6 +296,12 @@ impl<S: Sip> Hasher<S> {
     // The hashing of multi-byte integers depends on endianness. E.g.:
     // - little-endian: `write_u32(0xDDCCBBAA)` == `write([0xAA, 0xBB, 0xCC, 0xDD])`
     // - big-endian:    `write_u32(0xDDCCBBAA)` == `write([0xDD, 0xCC, 0xBB, 0xAA])`
+    //
+    // This function does the right thing for little-endian hardware. On
+    // big-endian hardware `x` must be byte-swapped first to give the right
+    // behaviour. After any byte-swapping, the input must be zero-extended to
+    // 64-bits. The caller is responsible for the byte-swapping and
+    // zero-extension.
     #[inline]
     fn short_write<T>(&mut self, _x: T, x: u64) {
         let size = mem::size_of::<T>();
@@ -437,7 +443,7 @@ impl hash::Hasher for SipHasher24 {
 impl<S: Sip> hash::Hasher for Hasher<S> {
     #[inline]
     fn write_usize(&mut self, i: usize) {
-        self.short_write(i, i as u64);
+        self.short_write(i, i.to_le() as u64);
     }
 
     #[inline]
@@ -447,12 +453,12 @@ impl<S: Sip> hash::Hasher for Hasher<S> {
 
     #[inline]
     fn write_u32(&mut self, i: u32) {
-        self.short_write(i, i as u64);
+        self.short_write(i, i.to_le() as u64);
     }
 
     #[inline]
     fn write_u64(&mut self, i: u64) {
-        self.short_write(i, i);
+        self.short_write(i, i.to_le());
     }
 
     #[inline]
diff --git a/src/sip128.rs b/src/sip128.rs
index a953783..5ed14e8 100644
--- a/src/sip128.rs
+++ b/src/sip128.rs
@@ -341,6 +341,12 @@ impl<S: Sip> Hasher<S> {
     // The hashing of multi-byte integers depends on endianness. E.g.:
     // - little-endian: `write_u32(0xDDCCBBAA)` == `write([0xAA, 0xBB, 0xCC, 0xDD])`
     // - big-endian:    `write_u32(0xDDCCBBAA)` == `write([0xDD, 0xCC, 0xBB, 0xAA])`
+    //
+    // This function does the right thing for little-endian hardware. On
+    // big-endian hardware `x` must be byte-swapped first to give the right
+    // behaviour. After any byte-swapping, the input must be zero-extended to
+    // 64-bits. The caller is responsible for the byte-swapping and
+    // zero-extension.
     #[inline]
     fn short_write<T>(&mut self, _x: T, x: u64) {
         let size = mem::size_of::<T>();
@@ -505,7 +511,7 @@ impl hash::Hasher for SipHasher24 {
 impl<S: Sip> hash::Hasher for Hasher<S> {
     #[inline]
     fn write_usize(&mut self, i: usize) {
-        self.short_write(i, i as u64);
+        self.short_write(i, i.to_le() as u64);
     }
 
     #[inline]
@@ -515,12 +521,12 @@ impl<S: Sip> hash::Hasher for Hasher<S> {
 
     #[inline]
     fn write_u32(&mut self, i: u32) {
-        self.short_write(i, i as u64);
+        self.short_write(i, i.to_le() as u64);
     }
 
     #[inline]
     fn write_u64(&mut self, i: u64) {
-        self.short_write(i, i);
+        self.short_write(i, i.to_le());
     }
 
     #[inline]