From 1b6a04ca5504955c571d1c97504fb45ea0befee4 Mon Sep 17 00:00:00 2001
From: Valentin Popov <valentin@popov.link>
Date: Mon, 8 Jan 2024 01:21:28 +0400
Subject: Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
---
vendor/image/src/codecs/webp/transform.rs | 77 +++++++++++++++++++++++++++++++
1 file changed, 77 insertions(+)
create mode 100644 vendor/image/src/codecs/webp/transform.rs
(limited to 'vendor/image/src/codecs/webp/transform.rs')
diff --git a/vendor/image/src/codecs/webp/transform.rs b/vendor/image/src/codecs/webp/transform.rs
new file mode 100644
index 0000000..3b3ef5a
--- /dev/null
+++ b/vendor/image/src/codecs/webp/transform.rs
@@ -0,0 +1,77 @@
+static CONST1: i64 = 20091;
+static CONST2: i64 = 35468;
+
+pub(crate) fn idct4x4(block: &mut [i32]) {
+ // The intermediate results may overflow the types, so we stretch the type.
+ fn fetch(block: &mut [i32], idx: usize) -> i64 {
+ i64::from(block[idx])
+ }
+
+ for i in 0usize..4 {
+ let a1 = fetch(block, i) + fetch(block, 8 + i);
+ let b1 = fetch(block, i) - fetch(block, 8 + i);
+
+ let t1 = (fetch(block, 4 + i) * CONST2) >> 16;
+ let t2 = fetch(block, 12 + i) + ((fetch(block, 12 + i) * CONST1) >> 16);
+ let c1 = t1 - t2;
+
+ let t1 = fetch(block, 4 + i) + ((fetch(block, 4 + i) * CONST1) >> 16);
+ let t2 = (fetch(block, 12 + i) * CONST2) >> 16;
+ let d1 = t1 + t2;
+
+ block[i] = (a1 + d1) as i32;
+ block[4 + i] = (b1 + c1) as i32;
+ block[4 * 3 + i] = (a1 - d1) as i32;
+ block[4 * 2 + i] = (b1 - c1) as i32;
+ }
+
+ for i in 0usize..4 {
+ let a1 = fetch(block, 4 * i) + fetch(block, 4 * i + 2);
+ let b1 = fetch(block, 4 * i) - fetch(block, 4 * i + 2);
+
+ let t1 = (fetch(block, 4 * i + 1) * CONST2) >> 16;
+ let t2 = fetch(block, 4 * i + 3) + ((fetch(block, 4 * i + 3) * CONST1) >> 16);
+ let c1 = t1 - t2;
+
+ let t1 = fetch(block, 4 * i + 1) + ((fetch(block, 4 * i + 1) * CONST1) >> 16);
+ let t2 = (fetch(block, 4 * i + 3) * CONST2) >> 16;
+ let d1 = t1 + t2;
+
+ block[4 * i] = ((a1 + d1 + 4) >> 3) as i32;
+ block[4 * i + 3] = ((a1 - d1 + 4) >> 3) as i32;
+ block[4 * i + 1] = ((b1 + c1 + 4) >> 3) as i32;
+ block[4 * i + 2] = ((b1 - c1 + 4) >> 3) as i32;
+ }
+}
+
+// 14.3
+pub(crate) fn iwht4x4(block: &mut [i32]) {
+ for i in 0usize..4 {
+ let a1 = block[i] + block[12 + i];
+ let b1 = block[4 + i] + block[8 + i];
+ let c1 = block[4 + i] - block[8 + i];
+ let d1 = block[i] - block[12 + i];
+
+ block[i] = a1 + b1;
+ block[4 + i] = c1 + d1;
+ block[8 + i] = a1 - b1;
+ block[12 + i] = d1 - c1;
+ }
+
+ for i in 0usize..4 {
+ let a1 = block[4 * i] + block[4 * i + 3];
+ let b1 = block[4 * i + 1] + block[4 * i + 2];
+ let c1 = block[4 * i + 1] - block[4 * i + 2];
+ let d1 = block[4 * i] - block[4 * i + 3];
+
+ let a2 = a1 + b1;
+ let b2 = c1 + d1;
+ let c2 = a1 - b1;
+ let d2 = d1 - c1;
+
+ block[4 * i] = (a2 + 3) >> 3;
+ block[4 * i + 1] = (b2 + 3) >> 3;
+ block[4 * i + 2] = (c2 + 3) >> 3;
+ block[4 * i + 3] = (d2 + 3) >> 3;
+ }
+}
--
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