unix ffi i/o copy task works

library/io/buffer.factor

@@ -15,7 +15,7 @@ TUPLE: buffer size ptr fill pos ;
     "int" "libc" "realloc" [ "ulong" "ulong" ] alien-invoke ;
 
 : imemcpy ( dst src size -- )
-    "void" "libc" "realloc" [ "ulong" "ulong" "ulong" ] alien-invoke ;
+    "void" "libc" "memcpy" [ "ulong" "ulong" "ulong" ] alien-invoke ;
 
 C: buffer ( size -- buffer )
     2dup set-buffer-size
@@ -92,6 +92,11 @@ C: buffer ( size -- buffer )
     [ buffer@ <alien> 0 alien-unsigned-1  1 ] keep
     buffer-consume ;
 
+: buffer-append ( buffer buffer -- )
+    #! Append first buffer to second buffer.
+    2dup buffer-end over buffer-ptr rot buffer-fill imemcpy
+    >r buffer-fill r> n>buffer ;
+
 : buffer-set ( string buffer -- )
     2dup buffer-ptr string>memory
     >r string-length r> buffer-reset ;

library/test/io/buffer.factor

@@ -36,3 +36,10 @@ USING: kernel io-internals test ;
     "hello" string>buffer
     1 over buffer-consume [ buffer-pop ] keep buffer-free
 ] unit-test
+
+[ "Hello world" ] [
+    " world" string>buffer
+    "Hello" string>buffer
+    2dup buffer-append
+    [ buffer-contents ] keep buffer-free swap buffer-free
+] unit-test

library/unix/io.factor

@@ -3,6 +3,10 @@
 IN: io-internals
 USING: errors generic kernel math sequences strings ;
 
+FORGET: can-read-line?
+FORGET: can-read-count?
+FORGET: can-write?
+
 : file-mode OCT: 0600 ;
 
 : io-error ( n -- ) 0 < [ errno strerror throw ] when ;
@@ -14,10 +18,6 @@ USING: errors generic kernel math sequences strings ;
     O_WRONLY O_CREAT bitor O_TRUNC bitor file-mode sys-open
     dup io-error ;
 
-FORGET: can-read-line?
-FORGET: can-read-count?
-FORGET: can-write?
-
 TUPLE: port handle buffer error ;
 
 C: port ( handle buffer -- port )
@@ -155,16 +155,13 @@ C: writer ( fd -- writer )
 : can-copy? ( from -- ? )
     dup eof? [ read-step ] [ drop t ] ifte ;
 
-: copy-from-step ( from to -- )
-    >r dup buffer-ptr swap buffer-fill r> buffer@ -rot imemcpy ;
-
 : copy-from-task ( from to -- ? )
     over can-copy? [
         over eof? [
             2drop t
         ] [
             over buffer-fill over can-write? [
-                dupd copy-from-step 0 swap buffer-reset
+                dupd buffer-append 0 swap buffer-reset
             ] [
                 2drop
             ] ifte f