speed up cmp(SubString,SubString)

About 1.5x faster. Helps with JuliaLang#8826.
tknopp · Nov 14, 2014 · cf7f24f · cf7f24f
1 parent dff8e03
commit cf7f24f
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/base/string.jl b/base/string.jl
@@ -654,6 +654,14 @@ end
 
 isascii(s::SubString{ASCIIString}) = true
 
+function cmp{T<:ByteString,S<:ByteString}(a::SubString{T}, b::SubString{S})
+ na = sizeof(a)
+ nb = sizeof(b)
+ c = ccall(:memcmp, Int32, (Ptr{UInt8}, Ptr{UInt8}, UInt),
+ pointer(a), pointer(b), min(na,nb))
+ c < 0 ? -1 : c > 0 ? +1 : cmp(na,nb)
+end
+
 ## hashing strings ##
 
 const memhash = UInt === UInt64 ? :memhash_seed : :memhash32_seed