Use clampInt (#231)

Replace min(max(...), ...) with clampInt.

Author: jmr

s2/builder_snapper.go

@@ -435,8 +435,8 @@ func (sf IntLatLngSnapper) exponentForMaxSnapRadius(snapRadius s1.Angle) int {
 	// There can be small errors in the calculation above, so to ensure that
 	// this function is the inverse of minSnapRadiusForExponent we subtract a
 	// small error tolerance.
-	return max(minIntSnappingExponent,
-		min(maxIntSnappingExponent, int(math.Ceil(exponent-2*dblEpsilon))))
+	return clampInt(int(math.Ceil(exponent-2*dblEpsilon)),
+		minIntSnappingExponent, maxIntSnappingExponent)
 }
 
 // MinVertexSeparation reports the minimum separation between vertices depending on

s2/regioncoverer.go

@@ -336,24 +336,24 @@ func (c *coverer) coveringInternal(region Region) {
 // newCoverer returns an instance of coverer.
 func (rc *RegionCoverer) newCoverer() *coverer {
 	return &coverer{
-		minLevel: max(0, min(MaxLevel, rc.MinLevel)),
-		MaxLevel: max(0, min(MaxLevel, rc.MaxLevel)),
-		levelMod: max(1, min(3, rc.LevelMod)),
+		minLevel: clampInt(rc.MinLevel, 0, MaxLevel),
+		MaxLevel: clampInt(rc.MaxLevel, 0, MaxLevel),
+		levelMod: clampInt(rc.LevelMod, 1, 3),
 		maxCells: rc.MaxCells,
 	}
 }
 
 // Covering returns a CellUnion that covers the given region and satisfies the various restrictions.
 func (rc *RegionCoverer) Covering(region Region) CellUnion {
 	covering := rc.CellUnion(region)
-	covering.Denormalize(max(0, min(MaxLevel, rc.MinLevel)), max(1, min(3, rc.LevelMod)))
+	covering.Denormalize(clampInt(rc.MinLevel, 0, MaxLevel), clampInt(rc.LevelMod, 1, 3))
 	return covering
 }
 
 // InteriorCovering returns a CellUnion that is contained within the given region and satisfies the various restrictions.
 func (rc *RegionCoverer) InteriorCovering(region Region) CellUnion {
 	intCovering := rc.InteriorCellUnion(region)
-	intCovering.Denormalize(max(0, min(MaxLevel, rc.MinLevel)), max(1, min(3, rc.LevelMod)))
+	intCovering.Denormalize(clampInt(rc.MinLevel, 0, MaxLevel), clampInt(rc.LevelMod, 1, 3))
 	return intCovering
 }