From f1666d981aab4e4cf94b91dc097675fa0b056c97 Mon Sep 17 00:00:00 2001
From: Lukas Larsson <lukas@erlang.org>
Date: Thu, 12 Oct 2017 15:55:04 +0200
Subject: stdlib: Make io_lib and io_lib_pretty use maps iterator

---
 bootstrap/lib/stdlib/ebin/io_lib.beam        | Bin 11948 -> 13240 bytes
 bootstrap/lib/stdlib/ebin/io_lib_pretty.beam | Bin 17140 -> 17288 bytes
 lib/stdlib/src/io_lib.erl                    |  13 ++++++++++++-
 lib/stdlib/src/io_lib_pretty.erl             |  12 +++++++++++-
 lib/stdlib/test/io_SUITE.erl                 |   4 ++--
 5 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/bootstrap/lib/stdlib/ebin/io_lib.beam b/bootstrap/lib/stdlib/ebin/io_lib.beam
index 82642fb353..c0a8f7212e 100644
Binary files a/bootstrap/lib/stdlib/ebin/io_lib.beam and b/bootstrap/lib/stdlib/ebin/io_lib.beam differ
diff --git a/bootstrap/lib/stdlib/ebin/io_lib_pretty.beam b/bootstrap/lib/stdlib/ebin/io_lib_pretty.beam
index 6ed1e3b7cc..76e56eb399 100644
Binary files a/bootstrap/lib/stdlib/ebin/io_lib_pretty.beam and b/bootstrap/lib/stdlib/ebin/io_lib_pretty.beam differ
diff --git a/lib/stdlib/src/io_lib.erl b/lib/stdlib/src/io_lib.erl
index 9d447418f8..3c8430b820 100644
--- a/lib/stdlib/src/io_lib.erl
+++ b/lib/stdlib/src/io_lib.erl
@@ -963,7 +963,18 @@ limit_tail(Other, D) ->
 %% maps:from_list() creates a map with the same internal ordering of
 %% the selected associations as in Map.
 limit_map(Map, D) ->
-    maps:from_list(erts_internal:maps_to_list(Map, D)).
+    limit_map(maps:iterator(Map), D, []).
+
+limit_map(_I, 0, Acc) ->
+    maps:from_list(Acc);
+limit_map(I, D, Acc) ->
+    case maps:next(I) of
+        {K, V, NextI} ->
+            limit_map(NextI, D-1, [{K,V} | Acc]);
+        none ->
+            maps:from_list(Acc)
+    end.
+
 %%     maps:from_list(limit_map_body(erts_internal:maps_to_list(Map, D), D)).
 
 %% limit_map_body(_, 0) -> [{'...', '...'}];
diff --git a/lib/stdlib/src/io_lib_pretty.erl b/lib/stdlib/src/io_lib_pretty.erl
index 505613b80e..89e1931d2d 100644
--- a/lib/stdlib/src/io_lib_pretty.erl
+++ b/lib/stdlib/src/io_lib_pretty.erl
@@ -478,9 +478,19 @@ print_length(Term, _D, _RF, _Enc, _Str) ->
 print_length_map(_Map, 1, _RF, _Enc, _Str) ->
     {"#{...}", 6};
 print_length_map(Map, D, RF, Enc, Str) when is_map(Map) ->
-    Pairs = print_length_map_pairs(erts_internal:maps_to_list(Map, D), D, RF, Enc, Str),
+    Pairs = print_length_map_pairs(limit_map(maps:iterator(Map), D, []), D, RF, Enc, Str),
     {{map, Pairs}, list_length(Pairs, 3)}.
 
+limit_map(_I, 0, Acc) ->
+    Acc;
+limit_map(I, D, Acc) ->
+    case maps:next(I) of
+        {K, V, NextI} ->
+            limit_map(NextI, D-1, [{K,V} | Acc]);
+        none ->
+            Acc
+    end.
+
 print_length_map_pairs([], _D, _RF, _Enc, _Str) ->
     [];
 print_length_map_pairs(_Pairs, 1, _RF, _Enc, _Str) ->
diff --git a/lib/stdlib/test/io_SUITE.erl b/lib/stdlib/test/io_SUITE.erl
index e2c73371cd..13929bdbb6 100644
--- a/lib/stdlib/test/io_SUITE.erl
+++ b/lib/stdlib/test/io_SUITE.erl
@@ -2138,8 +2138,8 @@ otp_14175(_Config) ->
     "#{}" = p(#{}, 1),
     "#{...}" = p(#{a => 1}, 1),
     "#{#{} => a}" = p(#{#{} => a}, 2),
-    "#{a => 1,...}" = p(#{a => 1, b => 2}, 2),
-    "#{a => 1,b => 2}" = p(#{a => 1, b => 2}, -1),
+    mt("#{a => 1,...}", p(#{a => 1, b => 2}, 2)),
+    mt("#{a => 1,b => 2}", p(#{a => 1, b => 2}, -1)),
 
     M = #{kaaaaaaaaaaaaaaaaaaa => v1,kbbbbbbbbbbbbbbbbbbb => v2,
           kccccccccccccccccccc => v3,kddddddddddddddddddd => v4,
-- 
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