improve performance of parse (#28787)

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