avoid a copy in readuntil (JuliaLang#19946)

avoid a copy in readuntil
tekverkp · Jan 21, 2017 · b07b6dd · b07b6dd
1 parent 17b9724
commit b07b6dd
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/base/io.jl b/base/io.jl
@@ -390,9 +390,13 @@ function read(s::IO, ::Type{Char})
  return Char(c)
 end
 
+# readuntil_string is useful below since it has
+# an optimized method for s::IOStream
+readuntil_string(s::IO, delim::UInt8) = String(readuntil(s, delim))
+
 function readuntil(s::IO, delim::Char)
  if delim < Char(0x80)
- return String(readuntil(s, delim % UInt8))
+ return readuntil_string(s, delim % UInt8)
  end
  out = IOBuffer()
  while !eof(s)

diff --git a/base/iostream.jl b/base/iostream.jl
@@ -225,6 +225,11 @@ function readuntil(s::IOStream, delim::UInt8)
  ccall(:jl_readuntil, Array{UInt8,1}, (Ptr{Void}, UInt8, UInt8), s.ios, delim, 0)
 end
 
+# like readuntil, above, but returns a String without requiring a copy
+function readuntil_string(s::IOStream, delim::UInt8)
+ ccall(:jl_readuntil, Ref{String}, (Ptr{Void}, UInt8, UInt8), s.ios, delim, 1)
+end
+
 function readline(s::IOStream)
  ccall(:jl_readuntil, Ref{String}, (Ptr{Void}, UInt8, UInt8), s.ios, '\n', 1)
 end