From 699b588210e92ccd9b526df689698a5d4b24d87f Mon Sep 17 00:00:00 2001
From: Kristoffer Carlsson <kristoffer.carlsson@chalmers.se>
Date: Wed, 22 Aug 2018 12:10:22 +0200
Subject: [PATCH] improve performance of parse (#28787)

(cherry picked from commit 81850b6eaa7cc079005db752d1e381f7fb654196)
---
 base/parse.jl | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/base/parse.jl b/base/parse.jl
index d0037ca6a6574e..50b76e0577eb10 100644
--- a/base/parse.jl
+++ b/base/parse.jl
@@ -106,14 +106,21 @@ function tryparse_internal(::Type{T}, s::AbstractString, startpos::Int, endpos::
         return nothing
     end
 
-    base = convert(T,base)
-    m::T = div(typemax(T)-base+1,base)
+    base = convert(T, base)
+    m::T = div(typemax(T) - base + 1, base)
     n::T = 0
     a::Int = base <= 36 ? 10 : 36
+    _0 = UInt32('0')
+    _9 = UInt32('9')
+    _A = UInt32('A')
+    _a = UInt32('a')
+    _Z = UInt32('Z')
+    _z = UInt32('z')
     while n <= m
-        d::T = '0' <= c <= '9' ? c-'0'    :
-               'A' <= c <= 'Z' ? c-'A'+10 :
-               'a' <= c <= 'z' ? c-'a'+a  : base
+        _c = UInt32(c)
+        d::T = _0 <= _c <= _9 ? _c-_0             :
+               _A <= _c <= _Z ? _c-_A+ UInt32(10) :
+               _a <= _c <= _z ? _c-_a+a           : base
         if d >= base
             raise && throw(ArgumentError("invalid base $base digit $(repr(c)) in $(repr(SubString(s,startpos,endpos)))"))
             return nothing
@@ -129,9 +136,10 @@ function tryparse_internal(::Type{T}, s::AbstractString, startpos::Int, endpos::
     end
     (T <: Signed) && (n *= sgn)
     while !isspace(c)
-        d::T = '0' <= c <= '9' ? c-'0'    :
-        'A' <= c <= 'Z' ? c-'A'+10 :
-            'a' <= c <= 'z' ? c-'a'+a  : base
+        _c = UInt32(c)
+        d::T = _0 <= _c <= _9 ? _c-_0             :
+               _A <= _c <= _Z ? _c-_A+ UInt32(10) :
+               _a <= _c <= _z ? _c-_a+a           : base
         if d >= base
             raise && throw(ArgumentError("invalid base $base digit $(repr(c)) in $(repr(SubString(s,startpos,endpos)))"))
             return nothing