From 6c38f1a50348b7e2474a4bed72b592d0496a6273 Mon Sep 17 00:00:00 2001
From: Folkert <folkert@folkertdev.nl>
Date: Wed, 6 Mar 2024 20:02:01 +0100
Subject: [PATCH] `enum Rav1dChromaSamplePosition`: make a real enum

---
 include/dav1d/headers.rs | 41 +++++++++++++++++++++++++++++++---------
 src/obu.rs               |  9 ++++-----
 2 files changed, 36 insertions(+), 14 deletions(-)

diff --git a/include/dav1d/headers.rs b/include/dav1d/headers.rs
index 2cb311117..371dcfd41 100644
--- a/include/dav1d/headers.rs
+++ b/include/dav1d/headers.rs
@@ -562,14 +562,37 @@ pub(crate) const _RAV1D_MC_BT709: Rav1dMatrixCoefficients = DAV1D_MC_BT709;
 pub(crate) const RAV1D_MC_IDENTITY: Rav1dMatrixCoefficients = DAV1D_MC_IDENTITY;
 
 pub type Dav1dChromaSamplePosition = c_uint;
-pub const DAV1D_CHR_COLOCATED: Dav1dChromaSamplePosition = 2;
-pub const DAV1D_CHR_VERTICAL: Dav1dChromaSamplePosition = 1;
-pub const DAV1D_CHR_UNKNOWN: Dav1dChromaSamplePosition = 0;
+pub const DAV1D_CHR_UNKNOWN: Dav1dChromaSamplePosition =
+    Rav1dChromaSamplePosition::Unknown as Dav1dChromaSamplePosition;
+pub const DAV1D_CHR_VERTICAL: Dav1dChromaSamplePosition =
+    Rav1dChromaSamplePosition::_Vertical as Dav1dChromaSamplePosition;
+pub const DAV1D_CHR_COLOCATED: Dav1dChromaSamplePosition =
+    Rav1dChromaSamplePosition::_Colocated as Dav1dChromaSamplePosition;
 
-pub(crate) type Rav1dChromaSamplePosition = c_uint;
-pub(crate) const _RAV1D_CHR_COLOCATED: Rav1dChromaSamplePosition = DAV1D_CHR_COLOCATED;
-pub(crate) const _RAV1D_CHR_VERTICAL: Rav1dChromaSamplePosition = DAV1D_CHR_VERTICAL;
-pub(crate) const RAV1D_CHR_UNKNOWN: Rav1dChromaSamplePosition = DAV1D_CHR_UNKNOWN;
+#[derive(Clone, Copy, PartialEq, Eq, FromRepr)]
+pub enum Rav1dChromaSamplePosition {
+    Unknown = 0,
+    /// Horizontally co-located with (0, 0) luma sample, vertical position
+    /// in the middle between two luma samples
+    _Vertical = 1,
+    /// co-located with (0, 0) luma sample
+    _Colocated = 2,
+    _Reserved = 3,
+}
+
+impl From<Rav1dChromaSamplePosition> for Dav1dChromaSamplePosition {
+    fn from(value: Rav1dChromaSamplePosition) -> Self {
+        value as Dav1dChromaSamplePosition
+    }
+}
+
+impl TryFrom<Dav1dChromaSamplePosition> for Rav1dChromaSamplePosition {
+    type Error = ();
+
+    fn try_from(value: Dav1dChromaSamplePosition) -> Result<Self, Self::Error> {
+        Self::from_repr(value as usize).ok_or(())
+    }
+}
 
 #[repr(C)]
 pub struct Rav1dContentLightLevel {
@@ -1039,7 +1062,7 @@ impl From<Dav1dSequenceHeader> for Rav1dSequenceHeader {
             pri,
             trc,
             mtrx,
-            chr,
+            chr: chr.try_into().unwrap(),
             hbd,
             color_range,
             num_operating_points,
@@ -1154,7 +1177,7 @@ impl From<Rav1dSequenceHeader> for Dav1dSequenceHeader {
             pri,
             trc,
             mtrx,
-            chr,
+            chr: chr.into(),
             hbd,
             color_range,
             num_operating_points,
diff --git a/src/obu.rs b/src/obu.rs
index 5d4594e01..bc719d923 100644
--- a/src/obu.rs
+++ b/src/obu.rs
@@ -41,7 +41,6 @@ use crate::include::dav1d::headers::Rav1dSequenceHeaderOperatingPoint;
 use crate::include::dav1d::headers::Rav1dTransferCharacteristics;
 use crate::include::dav1d::headers::Rav1dTxfmMode;
 use crate::include::dav1d::headers::Rav1dWarpedMotionParams;
-use crate::include::dav1d::headers::RAV1D_CHR_UNKNOWN;
 use crate::include::dav1d::headers::RAV1D_COLOR_PRI_BT709;
 use crate::include::dav1d::headers::RAV1D_COLOR_PRI_UNKNOWN;
 use crate::include::dav1d::headers::RAV1D_MAX_CDEF_STRENGTHS;
@@ -415,7 +414,7 @@ fn parse_seq_hdr(c: &mut Rav1dContext, gb: &mut GetBits) -> Rav1dResult<Rav1dSeq
         layout = Rav1dPixelLayout::I400;
         ss_ver = 1;
         ss_hor = ss_ver;
-        chr = RAV1D_CHR_UNKNOWN;
+        chr = Rav1dChromaSamplePosition::Unknown;
     } else if pri == RAV1D_COLOR_PRI_BT709 && trc == RAV1D_TRC_SRGB && mtrx == RAV1D_MC_IDENTITY {
         layout = Rav1dPixelLayout::I444;
         color_range = 1;
@@ -426,7 +425,7 @@ fn parse_seq_hdr(c: &mut Rav1dContext, gb: &mut GetBits) -> Rav1dResult<Rav1dSeq
         // Default initialization.
         ss_hor = Default::default();
         ss_ver = Default::default();
-        chr = Default::default();
+        chr = Rav1dChromaSamplePosition::Unknown;
     } else {
         color_range = gb.get_bit() as c_int;
         match profile {
@@ -470,9 +469,9 @@ fn parse_seq_hdr(c: &mut Rav1dContext, gb: &mut GetBits) -> Rav1dResult<Rav1dSeq
             _ => unreachable!(), // TODO(kkysen) Make `profile` an `enum` so this isn't needed.
         }
         chr = if ss_hor & ss_ver != 0 {
-            gb.get_bits(2) as Rav1dChromaSamplePosition
+            Rav1dChromaSamplePosition::from_repr(gb.get_bits(2) as usize).unwrap()
         } else {
-            RAV1D_CHR_UNKNOWN
+            Rav1dChromaSamplePosition::Unknown
         };
     }
     if c.strict_std_compliance && mtrx == RAV1D_MC_IDENTITY && layout != Rav1dPixelLayout::I444 {