From b259c6104553ff0ddf49fea6b6f568ac28aed848 Mon Sep 17 00:00:00 2001
From: Khyber Sen <kkysen@gmail.com>
Date: Tue, 24 Oct 2023 02:20:56 -0700
Subject: [PATCH] `static ss_size_mul`: Make an `EnumMap`.

---
 include/dav1d/headers.rs |  9 +++++++++
 src/decode.rs            | 25 +++++++++++++++----------
 src/enum_map.rs          |  5 +----
 3 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/include/dav1d/headers.rs b/include/dav1d/headers.rs
index d4eeee3fb..23d5f4117 100644
--- a/include/dav1d/headers.rs
+++ b/include/dav1d/headers.rs
@@ -1,3 +1,4 @@
+use crate::src::enum_map::EnumKey;
 use std::ffi::c_int;
 use std::ffi::c_uint;
 use std::ops::BitAnd;
@@ -208,6 +209,14 @@ pub(crate) enum Rav1dPixelLayout {
     I444,
 }
 
+impl EnumKey<4> for Rav1dPixelLayout {
+    const VALUES: [Self; 4] = [Self::I400, Self::I420, Self::I422, Self::I444];
+
+    fn as_usize(self) -> usize {
+        self as usize
+    }
+}
+
 impl BitAnd for Rav1dPixelLayout {
     type Output = bool;
 
diff --git a/src/decode.rs b/src/decode.rs
index 189198bc8..82ee4d9e6 100644
--- a/src/decode.rs
+++ b/src/decode.rs
@@ -42,6 +42,9 @@ use crate::src::ctx::CaseSet;
 use crate::src::data::rav1d_data_props_copy;
 use crate::src::data::rav1d_data_unref_internal;
 use crate::src::dequant_tables::dav1d_dq_tbl;
+use crate::src::enum_map::enum_map;
+use crate::src::enum_map::DefaultValue;
+use crate::src::enum_map::EnumMap;
 use crate::src::env::av1_get_bwd_ref_1_ctx;
 use crate::src::env::av1_get_bwd_ref_ctx;
 use crate::src::env::av1_get_fwd_ref_1_ctx;
@@ -3809,15 +3812,17 @@ fn reset_context(ctx: &mut BlockContext, keyframe: bool, pass: c_int) {
     ctx.pal_sz.0.fill(0);
 }
 
+impl DefaultValue for [u8; 2] {
+    const DEFAULT: Self = [0; 2];
+}
+
 /// `{ Y+U+V, Y+U } * 4`
-static ss_size_mul: [[u8; 2]; 4] = {
-    let mut a = [[0; 2]; 4];
-    a[Rav1dPixelLayout::I400 as usize] = [4, 4];
-    a[Rav1dPixelLayout::I420 as usize] = [6, 5];
-    a[Rav1dPixelLayout::I422 as usize] = [8, 6];
-    a[Rav1dPixelLayout::I444 as usize] = [12, 8];
-    a
-};
+static ss_size_mul: EnumMap<Rav1dPixelLayout, [u8; 2], 4> = enum_map!(Rav1dPixelLayout => [u8; 2]; match key {
+    I400 => [4, 4],
+    I420 => [6, 5],
+    I422 => [8, 6],
+    I444 => [12, 8],
+});
 
 unsafe fn setup_tile(
     ts: &mut Rav1dTileState,
@@ -3834,7 +3839,7 @@ unsafe fn setup_tile(
     let row_sb_end = (*f.frame_hdr).tiling.row_start_sb[tile_row + 1] as c_int;
     let sb_shift = f.sb_shift;
 
-    let size_mul = &ss_size_mul[f.cur.p.layout as usize];
+    let size_mul = &ss_size_mul[f.cur.p.layout];
     for p in 0..2 {
         ts.frame_thread[p].pal_idx = if !(f.frame_thread.pal_idx).is_null() {
             f.frame_thread
@@ -4290,7 +4295,7 @@ pub(crate) unsafe fn rav1d_decode_frame_init(f: &mut Rav1dFrameContext) -> Rav1d
     }
 
     let num_sb128 = f.sb128w * f.sb128h;
-    let size_mul = &ss_size_mul[f.cur.p.layout as usize];
+    let size_mul = &ss_size_mul[f.cur.p.layout];
     let hbd = ((*f.seq_hdr).hbd != 0) as c_int;
     if c.n_fc > 1 {
         let mut tile_idx = 0;
diff --git a/src/enum_map.rs b/src/enum_map.rs
index c74ff568d..0cc6d96be 100644
--- a/src/enum_map.rs
+++ b/src/enum_map.rs
@@ -31,7 +31,6 @@ where
 {
     /// Create an [`EnumMap`] from an existing array
     /// where the array's indices correspond to `K`'s values `as usize`.
-    #[allow(dead_code)]
     pub const fn new(array: [V; N]) -> Self {
         Self {
             array,
@@ -46,7 +45,7 @@ where
     V: DefaultValue,
 {
     /// Create an [`EnumMap`] with default values when `V: ` [`DefaultValue`].
-    #[allow(dead_code)]
+    #[allow(dead_code)] // TODO(kkysen) remove when used
     pub const fn default() -> Self {
         Self {
             array: [V::DEFAULT; N],
@@ -87,7 +86,6 @@ where
 /// but it also doesn't yet work in `const` contexts.
 ///
 /// [`MaybeUninit`]: std::mem::MaybeUninit
-#[allow(unused_macros)]
 macro_rules! enum_map {
     ($K:ty => $V:ty; match key { $($t:tt)* }) => {{
         use $crate::src::enum_map::EnumKey;
@@ -106,5 +104,4 @@ macro_rules! enum_map {
     }};
 }
 
-#[allow(unused_imports)]
 pub(crate) use enum_map;