From 6f5b0dc8d9905a28322a95e5bab813854c16b5f4 Mon Sep 17 00:00:00 2001
From: KristofferC <kcarlsson89@gmail.com>
Date: Tue, 5 May 2020 11:48:37 +0200
Subject: [PATCH 1/2] add better implementations for generic findprev findnext
 for AbstractString

---
 base/strings/search.jl | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/base/strings/search.jl b/base/strings/search.jl
index 9dec4f1db66cc..3db59b68aac35 100644
--- a/base/strings/search.jl
+++ b/base/strings/search.jl
@@ -127,16 +127,17 @@ findfirst(ch::AbstractChar, string::AbstractString) = findfirst(==(ch), string)
 function findnext(testf::Function, s::AbstractString, i::Integer)
     i = Int(i)
     z = ncodeunits(s) + 1
-    1 ≤ i ≤ z || throw(BoundsError(s, i))
+    1 ≤ i ≤ z || throw(BoundsError(s, i))
     @inbounds i == z || isvalid(s, i) || string_index_err(s, i)
-    for (j, d) in pairs(SubString(s, i))
-        if testf(d)
-            return i + j - 1
-        end
+    e = lastindex(s)
+    @inbounds while i <= e
+        testf(s[i]) && return i
+        i = nextind(s, i)
     end
     return nothing
 end
 
+
 in(c::AbstractChar, s::AbstractString) = (findfirst(isequal(c),s)!==nothing)
 
 function _searchindex(s::Union{AbstractString,ByteArray},
@@ -334,18 +335,16 @@ findlast(ch::AbstractChar, string::AbstractString) = findlast(==(ch), string)
 
 # AbstractString implementation of the generic findprev interface
 function findprev(testf::Function, s::AbstractString, i::Integer)
-    if i < 1
-        return i == 0 ? nothing : throw(BoundsError(s, i))
-    end
-    n = ncodeunits(s)
-    if i > n
-        return i == n+1 ? nothing : throw(BoundsError(s, i))
+    i = Int(i)
+    z = ncodeunits(s) + 1
+    0 ≤ i ≤ z || throw(BoundsError(s, i))
+    i == z && return nothing
+    @inbounds i == 0 || isvalid(s, i) || string_index_err(s, i)
+    @inbounds while i >= 1
+        testf(s[i]) && return i
+        i = prevind(s, i)
     end
-    # r[reverseind(r,i)] == reverse(r)[i] == s[i]
-    # s[reverseind(s,j)] == reverse(s)[j] == r[j]
-    r = reverse(s)
-    j = findnext(testf, r, reverseind(r, i))
-    j === nothing ? nothing : reverseind(s, j)
+    return nothing
 end
 
 function _rsearchindex(s::AbstractString,

From 30b8419b93a30adef008bd7319c8cfbfce3aada9 Mon Sep 17 00:00:00 2001
From: KristofferC <kcarlsson89@gmail.com>
Date: Wed, 6 May 2020 15:02:30 +0200
Subject: [PATCH 2/2] tweak inbounds usage

---
 base/strings/search.jl | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/base/strings/search.jl b/base/strings/search.jl
index 3db59b68aac35..9d2fdf73afff4 100644
--- a/base/strings/search.jl
+++ b/base/strings/search.jl
@@ -130,9 +130,9 @@ function findnext(testf::Function, s::AbstractString, i::Integer)
     1 ≤ i ≤ z || throw(BoundsError(s, i))
     @inbounds i == z || isvalid(s, i) || string_index_err(s, i)
     e = lastindex(s)
-    @inbounds while i <= e
-        testf(s[i]) && return i
-        i = nextind(s, i)
+    while i <= e
+        testf(@inbounds s[i]) && return i
+        i = @inbounds nextind(s, i)
     end
     return nothing
 end
@@ -340,9 +340,9 @@ function findprev(testf::Function, s::AbstractString, i::Integer)
     0 ≤ i ≤ z || throw(BoundsError(s, i))
     i == z && return nothing
     @inbounds i == 0 || isvalid(s, i) || string_index_err(s, i)
-    @inbounds while i >= 1
-        testf(s[i]) && return i
-        i = prevind(s, i)
+    while i >= 1
+        testf(@inbounds s[i]) && return i
+        i = @inbounds prevind(s, i)
     end
     return nothing
 end