From 68feb5f286d7f7fb3839d2434e4a0db24d6f5cf6 Mon Sep 17 00:00:00 2001
From: Jeremie Dimino <jdimino@janestreet.com>
Date: Wed, 24 Feb 2016 17:29:47 +0000
Subject: [PATCH] Add Misc.delete_eol_spaces

---
 utils/misc.ml  | 32 ++++++++++++++++++++++++++++++++
 utils/misc.mli |  4 ++++
 2 files changed, 36 insertions(+)

diff --git a/utils/misc.ml b/utils/misc.ml
index bc22a44cb..cf75391d6 100644
--- a/utils/misc.ml
+++ b/utils/misc.ml
@@ -652,3 +652,35 @@ let normalise_eol s =
       if s.[i] <> '\r' then Buffer.add_char b s.[i]
     done;
     Buffer.contents b
+
+let delete_eol_spaces src =
+  let len_src = String.length src in
+  let dst = Bytes.create len_src in
+  let rec loop i_src i_dst =
+    if i_src = len_src then
+      i_dst
+    else
+      match src.[i_src] with
+      | ' ' | '\t' ->
+        loop_spaces 1 (i_src + 1) i_dst
+      | c ->
+        Bytes.set dst i_dst c;
+        loop (i_src + 1) (i_dst + 1)
+  and loop_spaces spaces i_src i_dst =
+    if i_src = len_src then
+      i_dst
+    else
+      match src.[i_src] with
+      | ' ' | '\t' ->
+        loop_spaces (spaces + 1) (i_src + 1) i_dst
+      | '\n' ->
+        Bytes.set dst i_dst '\n';
+        loop (i_src + 1) (i_dst + 1)
+      | c ->
+        for n = 0 to spaces do
+          Bytes.set dst (i_dst + n) src.[i_src - spaces + n]
+        done;
+        loop (i_src + 1) (i_dst + spaces + 1)
+  in
+  let stop = loop 0 0 in
+  Bytes.sub_string dst 0 stop
diff --git a/utils/misc.mli b/utils/misc.mli
index f6ff10092..09745d381 100644
--- a/utils/misc.mli
+++ b/utils/misc.mli
@@ -310,3 +310,7 @@ val normalise_eol : string -> string
 (** [normalise_eol s] returns a fresh copy of [s] with any '\r' characters
    removed. Intended for pre-processing text which will subsequently be printed
    on a channel which performs EOL transformations (i.e. Windows) *)
+
+val delete_eol_spaces : string -> string
+(** [delete_eol_spaces s] returns a fresh copy of [s] with any end of line spaces
+   removed. Intended to normalize the output of the toplevel for tests. *)