From 8ad8ec679fe8ff970c075fb327d5b97f61a48220 Mon Sep 17 00:00:00 2001
From: Vincent Rabaud <vrabaud@users.noreply.github.com>
Date: Tue, 7 Mar 2023 13:05:38 +0100
Subject: [PATCH] Merge pull request #22441 from vrabaud:hls_while

In case of huge (and probably invalid) input, make sure we do not
rely only on the while loops for truncation.

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
---
 modules/imgproc/src/color_hsv.simd.hpp | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/modules/imgproc/src/color_hsv.simd.hpp b/modules/imgproc/src/color_hsv.simd.hpp
index 424a6d1494..0c30564a12 100644
--- a/modules/imgproc/src/color_hsv.simd.hpp
+++ b/modules/imgproc/src/color_hsv.simd.hpp
@@ -419,6 +419,14 @@ inline void HSV2RGB_simd(const v_float32& h, const v_float32& s, const v_float32
 }
 #endif
 
+// Compute the sector and the new H for HSV and HLS 2 RGB conversions.
+inline void ComputeSectorAndClampedH(float& h, int &sector) {
+    sector = cvFloor(h);
+    h -= sector;
+    sector %= 6;
+    sector += sector < 0 ? 6 : 0;
+}
+
 
 inline void HSV2RGB_native(float h, float s, float v,
                            float& b, float& g, float& r,
@@ -433,14 +441,7 @@ inline void HSV2RGB_native(float h, float s, float v,
         float tab[4];
         int sector;
         h *= hscale;
-        h = fmod(h, 6.f);
-        sector = cvFloor(h);
-        h -= sector;
-        if( (unsigned)sector >= 6u )
-        {
-            sector = 0;
-            h = 0.f;
-        }
+        ComputeSectorAndClampedH(h, sector);
 
         tab[0] = v;
         tab[1] = v*(1.f - s);
@@ -987,13 +988,7 @@ struct HLS2RGB_f
                 float p1 = 2*l - p2;
 
                 h *= hscale;
-                // We need both loops to clamp (e.g. for h == -1e-40).
-                while( h < 0 ) h += 6;
-                while( h >= 6 ) h -= 6;
-
-                CV_DbgAssert( 0 <= h && h < 6 );
-                sector = cvFloor(h);
-                h -= sector;
+                ComputeSectorAndClampedH(h, sector);
 
                 tab[0] = p2;
                 tab[1] = p1;