Do not use internal Base.first_utf8_byte

Project.toml

@@ -1,7 +1,7 @@
 name = "StringViews"
 uuid = "354b36f9-a18e-4713-926e-db85100087ba"
 authors = ["Steven G. Johnson <stevenj@alum.mit.edu>"]
-version = "1.3.5"
+version = "1.3.6"
 
 [compat]
 julia = "1.6"

src/search.jl

@@ -2,17 +2,22 @@
 
 nothing_sentinel(x) = iszero(x) ? nothing : x
 
+function first_utf8_byte(x::Char)::UInt8
+    u = reinterpret(UInt32, x)
+    (u >> 24) % UInt8
+end
+
 function Base.findnext(pred::Base.Fix2{<:Union{typeof(isequal),typeof(==)},<:AbstractChar},
                   s::StringViewAndSub, i::Integer)
     if i < 1 || i > sizeof(s)
         i == sizeof(s) + 1 && return nothing
         throw(BoundsError(s, i))
     end
     @inbounds isvalid(s, i) || Base.string_index_err(s, i)
-    c = pred.x
+    c = Char(pred.x)::Char
     c ≤ '\x7f' && return nothing_sentinel(Base._search(s, c % UInt8, i))
     while true
-        i = Base._search(s, Base.first_utf8_byte(c), i)
+        i = Base._search(s, first_utf8_byte(c), i)
         i == 0 && return nothing
         pred(s[i]) && return i
         i = nextind(s, i)
@@ -45,7 +50,7 @@ function Base.findprev(pred::Base.Fix2{<:Union{typeof(isequal),typeof(==)},<:Abs
                   s::StringViewAndSub, i::Integer)
     c = pred.x
     c ≤ '\x7f' && return nothing_sentinel(Base._rsearch(s, c % UInt8, i))
-    b = Base.first_utf8_byte(c)
+    b = first_utf8_byte(c)
     while true
         i = Base._rsearch(s, b, i)
         i == 0 && return nothing

test/runtests.jl

@@ -142,6 +142,11 @@ end
         pat = r"(\.[\d]{3})\d+" => s"\g<1>"
         @test replace(String(copy(v)), pat) == replace(StringView(v), pat)
     end
+
+    @test findfirst(==('ø'), StringView("abc")) === nothing
+    @test findfirst(==('ø'), StringView("abæø")) == 5
+    @test findlast(==('ø'), StringView("abc")) === nothing
+    @test findlast(==('ø'), StringView("abæø")) == 5
 end
 
 @testset "replace" begin