From 0641dac7f0aa6c055fca8ab633ad85859d0ddd97 Mon Sep 17 00:00:00 2001
From: mat <github@matdoes.dev>
Date: Thu, 23 Mar 2023 20:20:13 -0500
Subject: simd number arrays

---
 azalea-nbt/src/encode.rs | 73 +++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 69 insertions(+), 4 deletions(-)

(limited to 'azalea-nbt/src/encode.rs')

diff --git a/azalea-nbt/src/encode.rs b/azalea-nbt/src/encode.rs
index bf56c223..f5195327 100755
--- a/azalea-nbt/src/encode.rs
+++ b/azalea-nbt/src/encode.rs
@@ -2,6 +2,7 @@ use crate::tag::*;
 use azalea_buf::McBufWritable;
 use byteorder::{WriteBytesExt, BE};
 use flate2::write::{GzEncoder, ZlibEncoder};
+use packed_simd_2::{i32x16, i32x2, i32x4, i32x8, i64x2, i64x4, i64x8};
 use std::io::Write;
 
 #[inline(always)]
@@ -81,14 +82,78 @@ fn write_list(writer: &mut impl Write, value: &NbtList) {
         }
         NbtList::Int(l) => {
             writer.write_i32::<BE>(l.len() as i32).unwrap();
-            for &v in l {
-                writer.write_i32::<BE>(v).unwrap();
+            // flip the bits to big endian with simd
+            let l = l.as_slice();
+            let mut position = 0;
+            // x16
+            while l.len() - position >= 16 {
+                let l = unsafe { i32x16::from_slice_unaligned_unchecked(&l[position..]) };
+                l.to_be();
+                let l = unsafe { std::mem::transmute::<i32x16, [u8; 64]>(l) };
+                writer.write_all(&l).unwrap();
+                position += 16;
+            }
+            // x8
+            if l.len() - position >= 8 {
+                let l = unsafe { i32x8::from_slice_unaligned_unchecked(&l[position..]) };
+                l.to_be();
+                let l = unsafe { std::mem::transmute::<i32x8, [u8; 32]>(l) };
+                writer.write_all(&l).unwrap();
+                position += 8;
+            }
+            // x4
+            if l.len() - position >= 4 {
+                let l = unsafe { i32x4::from_slice_unaligned_unchecked(&l[position..]) };
+                l.to_be();
+                let l = unsafe { std::mem::transmute::<i32x4, [u8; 16]>(l) };
+                writer.write_all(&l).unwrap();
+                position += 4;
+            }
+            // x2
+            if l.len() - position >= 2 {
+                let l = unsafe { i32x2::from_slice_unaligned_unchecked(&l[position..]) };
+                l.to_be();
+                let l = unsafe { std::mem::transmute::<i32x2, [u8; 8]>(l) };
+                writer.write_all(&l).unwrap();
+                position += 2;
+            }
+            // x1 ... just a normal write_i32
+            if l.len() - position >= 1 {
+                writer.write_i32::<BE>(l[position]).unwrap();
             }
         }
         NbtList::Long(l) => {
             writer.write_i32::<BE>(l.len() as i32).unwrap();
-            for &v in l {
-                writer.write_i64::<BE>(v).unwrap();
+            // flip the bits to big endian with simd
+            let l = l.as_slice();
+            let mut position = 0;
+            // x16
+            while l.len() - position >= 8 {
+                let l = unsafe { i64x8::from_slice_unaligned_unchecked(&l[position..]) };
+                l.to_be();
+                let l = unsafe { std::mem::transmute::<i64x8, [u8; 64]>(l) };
+                writer.write_all(&l).unwrap();
+                position += 8;
+            }
+            // x4
+            if l.len() - position >= 4 {
+                let l = unsafe { i64x4::from_slice_unaligned_unchecked(&l[position..]) };
+                l.to_be();
+                let l = unsafe { std::mem::transmute::<i64x4, [u8; 32]>(l) };
+                writer.write_all(&l).unwrap();
+                position += 4;
+            }
+            // x2
+            if l.len() - position >= 2 {
+                let l = unsafe { i64x2::from_slice_unaligned_unchecked(&l[position..]) };
+                l.to_be();
+                let l = unsafe { std::mem::transmute::<i64x2, [u8; 16]>(l) };
+                writer.write_all(&l).unwrap();
+                position += 2;
+            }
+            // x1 ... just a normal write_i32
+            if l.len() - position >= 1 {
+                writer.write_i64::<BE>(l[position]).unwrap();
             }
         }
         NbtList::Float(l) => {
-- 
cgit v1.2.3