diff --git a/basis/hints/hints.factor b/basis/hints/hints.factor
index b6af773ce5..4093666eb7 100644
--- a/basis/hints/hints.factor
+++ b/basis/hints/hints.factor
@@ -96,8 +96,6 @@ M: object specializer-declaration class ;
 { string string }
 "specializer" set-word-prop
 
-\ find-last-sep { string sbuf } "specializer" set-word-prop
-
 \ >string { sbuf } "specializer" set-word-prop
 
 \ >array { { vector } } "specializer" set-word-prop
diff --git a/basis/io/streams/byte-array/byte-array.factor b/basis/io/streams/byte-array/byte-array.factor
index 9d89c3d814..b877e97cf1 100644
--- a/basis/io/streams/byte-array/byte-array.factor
+++ b/basis/io/streams/byte-array/byte-array.factor
@@ -1,5 +1,8 @@
+! Copyright (C) 2008, 2009 Daniel Ehrenberg
+! See http://factorcode.org/license.txt for BSD license.
 USING: byte-arrays byte-vectors kernel io.encodings io.streams.string
-sequences io namespaces io.encodings.private accessors ;
+sequences io namespaces io.encodings.private accessors sequences.private
+io.streams.sequence destructors ;
 IN: io.streams.byte-array
 
 : <byte-writer> ( encoding -- stream )
@@ -9,8 +12,16 @@ IN: io.streams.byte-array
     [ <byte-writer> ] dip [ output-stream get ] compose with-output-stream*
     dup encoder? [ stream>> ] when >byte-array ; inline
 
+TUPLE: byte-reader { underlying byte-array read-only } { i array-capacity } ;
+
+M: byte-reader stream-read-partial stream-read ;
+M: byte-reader stream-read sequence-read ;
+M: byte-reader stream-read1 sequence-read1 ;
+M: byte-reader stream-read-until sequence-read-until ;
+M: byte-reader dispose drop ;
+
 : <byte-reader> ( byte-array encoding -- stream )
-    [ >byte-vector dup reverse-here ] dip <decoder> ;
+    [ B{ } like 0 byte-reader boa ] dip <decoder> ;
 
 : with-byte-reader ( byte-array encoding quot -- )
     [ <byte-reader> ] dip with-input-stream* ; inline
diff --git a/core/checksums/crc32/crc32.factor b/core/checksums/crc32/crc32.factor
index 7ea2964411..47da144d4d 100644
--- a/core/checksums/crc32/crc32.factor
+++ b/core/checksums/crc32/crc32.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2006 Doug Coleman
 ! See http://factorcode.org/license.txt for BSD license.
 USING: kernel math sequences sequences.private namespaces
-words io io.binary io.files io.streams.string quotations
+words io io.binary io.files quotations
 definitions checksums ;
 IN: checksums.crc32
 
diff --git a/core/io/streams/sequence/sequence.factor b/core/io/streams/sequence/sequence.factor
new file mode 100644
index 0000000000..bbb3576c05
--- /dev/null
+++ b/core/io/streams/sequence/sequence.factor
@@ -0,0 +1,38 @@
+! Copyright (C) 2009 Daniel Ehrenberg
+! See http://factorcode.org/license.txt for BSD license.
+USING: sequences io kernel accessors math math.order ;
+IN: io.streams.sequence
+
+SLOT: underlying
+SLOT: i
+
+: >sequence-stream< ( stream -- i underlying )
+    [ i>> ] [ underlying>> ] bi ; inline
+
+: next ( stream -- )
+    [ 1+ ] change-i drop ;
+
+: sequence-read1 ( stream -- elt/f )
+    [ >sequence-stream< ?nth ]
+    [ next ] bi ; inline
+
+: add-length ( n stream -- i+n )
+    [ i>> + ] [ underlying>> length ] bi min  ;
+
+: (sequence-read) ( n stream -- seq/f )
+    [ add-length ] keep
+    [ [ swap dup ] change-i drop ]
+    [ underlying>> ] bi
+    subseq ; inline
+
+: sequence-read ( n stream -- seq/f )
+    dup >sequence-stream< bounds-check?
+    [ (sequence-read) ] [ 2drop f ] if ; inline
+
+: find-sep ( seps stream -- sep/f n )
+    swap [ >sequence-stream< ] dip
+    [ memq? ] curry find-from swap ; inline
+
+: sequence-read-until ( separators stream -- seq sep/f )
+    [ find-sep ] keep
+    [ sequence-read ] [ next ] bi swap ; inline
diff --git a/core/io/streams/string/string-tests.factor b/core/io/streams/string/string-tests.factor
index a6502046c8..967c0d4613 100644
--- a/core/io/streams/string/string-tests.factor
+++ b/core/io/streams/string/string-tests.factor
@@ -15,12 +15,12 @@ unit-test
 
 [ "xyzzy" ] [ [ "xyzzy" write ] with-string-writer ] unit-test
 
-[ "a" ] [ 1 SBUF" cba" stream-read ] unit-test
-[ "ab" ] [ 2 SBUF" cba" stream-read ] unit-test
-[ "abc" ] [ 3 SBUF" cba" stream-read ] unit-test
-[ "abc" ] [ 4 SBUF" cba" stream-read ] unit-test
+[ "a" ] [ 1 "abc" <string-reader> stream-read ] unit-test
+[ "ab" ] [ 2 "abc" <string-reader> stream-read ] unit-test
+[ "abc" ] [ 3 "abc" <string-reader> stream-read ] unit-test
+[ "abc" ] [ 4 "abc" <string-reader> stream-read ] unit-test
 [ "abc" f ] [
-    3 SBUF" cba" [ stream-read ] keep stream-read1
+    3 "abc" <string-reader> [ stream-read ] keep stream-read1
 ] unit-test
 
 [
diff --git a/core/io/streams/string/string.factor b/core/io/streams/string/string.factor
index 4582490726..73bf5f5efe 100644
--- a/core/io/streams/string/string.factor
+++ b/core/io/streams/string/string.factor
@@ -1,18 +1,12 @@
-! Copyright (C) 2003, 2009 Slava Pestov.
+! Copyright (C) 2003, 2009 Slava Pestov, Daniel Ehrenberg.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: accessors io kernel math namespaces sequences sbufs
-strings generic splitting continuations destructors
-io.streams.plain io.encodings math.order growable ;
+strings generic splitting continuations destructors sequences.private
+io.streams.plain io.encodings math.order growable io.streams.sequence ;
 IN: io.streams.string
 
 <PRIVATE
 
-: harden-as ( seq growble-exemplar -- newseq )
-    underlying>> like ;
-
-: growable-read-until ( growable n -- str )
-    >fixnum dupd tail-slice swap harden-as dup reverse-here ;
-
 SINGLETON: null-encoding
 
 M: null-encoding decode-char drop stream-read1 ;
@@ -32,34 +26,18 @@ M: growable stream-flush drop ;
     <string-writer> swap [ output-stream get ] compose with-output-stream*
     >string ; inline
 
-M: growable stream-read1 [ f ] [ pop ] if-empty ;
+! New implementation
 
-: find-last-sep ( seq seps -- n )
-    swap [ memq? ] curry find-last drop ;
+TUPLE: string-reader { underlying string read-only } { i array-capacity } ;
 
-M: growable stream-read-until
-    [ find-last-sep ] keep over [
-        [ swap 1+ growable-read-until ] 2keep [ nth ] 2keep
-        set-length
-    ] [
-        [ swap drop 0 growable-read-until f like f ] keep
-        delete-all
-    ] if ;
-
-M: growable stream-read
-    [
-        drop f
-    ] [
-        [ length swap - 0 max ] keep
-        [ swap growable-read-until ] 2keep
-        set-length
-    ] if-empty ;
-
-M: growable stream-read-partial
-    stream-read ;
+M: string-reader stream-read-partial stream-read ;
+M: string-reader stream-read sequence-read ;
+M: string-reader stream-read1 sequence-read1 ;
+M: string-reader stream-read-until sequence-read-until ;
+M: string-reader dispose drop ;
 
 : <string-reader> ( str -- stream )
-    >sbuf dup reverse-here null-encoding <decoder> ;
+    0 string-reader boa null-encoding <decoder> ;
 
 : with-string-reader ( str quot -- )
     [ <string-reader> ] dip with-input-stream ; inline