sdfsd.idr

import Data.Buffer

-- Redefining this here to modify it
%foreign "scheme:blodwen-new-buffer"
prim_newBuffer' : Int -> PrimIO Buffer

export
newBuffer' : HasIO io => (bytes : Int) -> io Buffer
newBuffer' size = primIO $ prim_newBuffer' size
-- No Maybe, if we can't allocate memory then die.

-- does nothing, Buffer is managed by scheme gc atm
free : HasIO io => Buffer -> io ()
free _ = pure ()

export
withAlloc : HasIO io => (bytes : Int) -> (Buffer -> io a) -> io a
withAlloc size act = do buf <- newBuffer' size
                        res <- act buf
                        free buf
                        pure res

{-
Given a signature like
char *curl_easy_unescape( CURL *curl, const char *url , int inlength, int *outlength );
we can replace occurences like  int *outlength  with Buffer in our foreign signature.
We can do that because pointers to c types in chez's ffi use bytevectors for arguments
on the scheme side and Buffer is a bytevector.
-}

%foreign "C:curl_easy_unescape,libcurl,curl/curl.h"
prim_curl_easy_unescape : Ptr HandlePtr -> (url : String) -> (url_len : Int)
                       -> Buffer -> PrimIO (Ptr String)

curl_easy_unescape : HasIO io => CurlHandle ty -> String -> io String
curl_easy_unescape (MkH h) str = do
  b <- newBuffer' 8 -- 64 bits allocated, don't really need them all
  strptr <- primIO $ prim_curl_easy_unescape h str 0 b
  res <- getInt32 b 0 -- Our c wrote an int, so take out an Int32
  printLn res -- this will print what curl_easy_unescape wrote into b
  ...
  other stuff