ft: 修改为基于otp23.2.4编写

README.md

@@ -2,6 +2,8 @@ eFmt
 =====
 
 An OTP library to format term, for efficient
+base on otp-23.2.4
+
 
 Build
 -----

src/eFmt_format.erl → src/eFmtFormat.erl

@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1996-2017. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2019. All Rights Reserved.
 %% 
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -17,11 +17,12 @@
 %% 
 %% %CopyrightEnd%
 %%
--module(eFmt_format).
+-module(eFmtFormat).
 
 %% Formatting functions of io library.
 
--export([fwrite/2,fwrite_g/1,indentation/2,scan/2,unscan/1,build/1]).
+-export([fwrite/2,fwrite/3,fwrite_g/1,indentation/2,scan/2,unscan/1,
+         build/1, build/2]).
 
 %%  Format the arguments in Args after string Format. Just generate
 %%  an error if there is an error in the arguments.
@@ -37,29 +38,55 @@
 %%  and it also splits the handling of the control characters into two
 %%  parts.
 
--spec fwrite(Format, Data) -> FormatList when
+-spec fwrite(Format, Data) -> io_lib:chars() when
       Format :: io:format(),
-      Data :: [term()],
-      FormatList :: [char() | eFmt:format_spec()].
+      Data :: [term()].
 
 fwrite(Format, Args) ->
     build(scan(Format, Args)).
 
+-spec fwrite(Format, Data, Options) -> io_lib:chars() when
+      Format :: io:format(),
+      Data :: [term()],
+      Options :: [Option],
+      Option :: {'chars_limit', CharsLimit},
+      CharsLimit :: io_lib:chars_limit().
+
+fwrite(Format, Args, Options) ->
+    build(scan(Format, Args), Options).
+
 %% Build the output text for a pre-parsed format list.
 
--spec build(FormatList) -> eFmt:chars() when
-      FormatList :: [char() | eFmt:format_spec()].
+-spec build(FormatList) -> io_lib:chars() when
+      FormatList :: [char() | io_lib:format_spec()].
 
 build(Cs) ->
-    Pc = pcount(Cs),
-    build(Cs, Pc, 0).
+    build(Cs, []).
+
+-spec build(FormatList, Options) -> io_lib:chars() when
+      FormatList :: [char() | io_lib:format_spec()],
+      Options :: [Option],
+      Option :: {'chars_limit', CharsLimit},
+      CharsLimit :: io_lib:chars_limit().
+
+build(Cs, Options) ->
+    CharsLimit = get_option(chars_limit, Options, -1),
+    Res1 = build_small(Cs),
+    {P, S, W, Other} = count_small(Res1),
+    case P + S + W of
+        0 ->
+            Res1;
+        NumOfLimited ->
+            RemainingChars = sub(CharsLimit, Other),
+            build_limited(Res1, P, NumOfLimited, RemainingChars, 0)
+    end.
 
 %% Parse all control sequences in the format string.
 
 -spec scan(Format, Data) -> FormatList when
       Format :: io:format(),
       Data :: [term()],
-      FormatList :: [char() | eFmt:format_spec()].
+      FormatList :: [char() | io_lib:format_spec()].
 
 scan(Format, Args) when is_atom(Format) ->
     scan(atom_to_list(Format), Args);
@@ -72,7 +99,7 @@ scan(Format, Args) ->
 %% list of arguments.
 
 -spec unscan(FormatList) -> {Format, Data} when
-      FormatList :: [char() | eFmt:format_spec()],
+      FormatList :: [char() | io_lib:format_spec()],
       Format :: io:format(),
       Data :: [term()].
 
@@ -95,7 +122,7 @@ print([]) ->
     [].
 
 print(C, F, Ad, P, Pad, Encoding, Strings) ->
-    [$~] ++ print_field_width(F, Ad) ++ print_precision(P) ++
+    [$~] ++ print_field_width(F, Ad) ++ print_precision(P, Pad) ++
         print_pad_char(Pad) ++ print_encoding(Encoding) ++
         print_strings(Strings) ++ [C].
 
@@ -103,8 +130,9 @@ print_field_width(none, _Ad) -> "";
 print_field_width(F, left) -> integer_to_list(-F);
 print_field_width(F, right) -> integer_to_list(F).
 
-print_precision(none) -> "";
-print_precision(P) -> [$. | integer_to_list(P)].
+print_precision(none, $\s) -> "";
+print_precision(none, _Pad) -> ".";  % pad must be second dot
+print_precision(P, _Pad) -> [$. | integer_to_list(P)].
 
 print_pad_char($\s) -> ""; % default, no need to make explicit
 print_pad_char(Pad) -> [$., Pad].
@@ -126,25 +154,23 @@ collect_cseq(Fmt0, Args0) ->
     {F,Ad,Fmt1,Args1} = field_width(Fmt0, Args0),
     {P,Fmt2,Args2} = precision(Fmt1, Args1),
     {Pad,Fmt3,Args3} = pad_char(Fmt2, Args2),
-    {Encoding,Fmt4,Args4} = encoding(Fmt3, Args3),
-    {Strings,Fmt5,Args5} = strings(Fmt4, Args4),
-    {C,As,Fmt6,Args6} = collect_cc(Fmt5, Args5),
-    FormatSpec = #{control_char => C, args => As, width => F, adjust => Ad,
-                   precision => P, pad_char => Pad, encoding => Encoding,
-                   strings => Strings},
-    {FormatSpec,Fmt6,Args6}.
-
-encoding([$t|Fmt],Args) ->
-    true = hd(Fmt) =/= $l,
-    {unicode,Fmt,Args};
-encoding(Fmt,Args) ->
-    {latin1,Fmt,Args}.
-
-strings([$l|Fmt],Args) ->
-    true = hd(Fmt) =/= $t,
-    {false,Fmt,Args};
-strings(Fmt,Args) ->
-    {true,Fmt,Args}.
+    Spec0 = #{width => F,
+              adjust => Ad,
+              precision => P,
+              pad_char => Pad,
+              encoding => latin1,
+              strings => true},
+    {Spec1,Fmt4} = modifiers(Fmt3, Spec0),
+    {C,As,Fmt5,Args4} = collect_cc(Fmt4, Args3),
+    Spec2 = Spec1#{control_char => C, args => As},
+    {Spec2,Fmt5,Args4}.
+
+modifiers([$t|Fmt], Spec) ->
+    modifiers(Fmt, Spec#{encoding => unicode});
+modifiers([$l|Fmt], Spec) ->
+    modifiers(Fmt, Spec#{strings => false});
+modifiers(Fmt, Spec) ->
+    {Spec, Fmt}.
 
 field_width([$-|Fmt0], Args0) ->
     {F,Fmt,Args} = field_value(Fmt0, Args0),
@@ -203,45 +229,88 @@ collect_cc([$~|Fmt], Args) when is_list(Args) -> {$~,[],Fmt,Args};
 collect_cc([$n|Fmt], Args) when is_list(Args) -> {$n,[],Fmt,Args};
 collect_cc([$i|Fmt], [A|Args]) -> {$i,[A],Fmt,Args}.
 
-%% pcount([ControlC]) -> Count.
-%%  Count the number of print requests.
-
-pcount(Cs) -> pcount(Cs, 0).
-
-pcount([#{control_char := $p}|Cs], Acc) -> pcount(Cs, Acc+1);
-pcount([#{control_char := $P}|Cs], Acc) -> pcount(Cs, Acc+1);
-pcount([_|Cs], Acc) -> pcount(Cs, Acc);
-pcount([], Acc) -> Acc.
-
-%% build([Control], Pc, Indentation) -> eFmt:chars().
+%% count_small([ControlC]) -> Count.
+%%  Count the number of big (pPwWsS) print requests and
+%%  number of characters of other print (small) requests.
+
+count_small(Cs) ->
+    count_small(Cs, #{p => 0, s => 0, w => 0, other => 0}).
+
+count_small([#{control_char := $p}|Cs], #{p := P} = Cnts) ->
+    count_small(Cs, Cnts#{p := P + 1});
+count_small([#{control_char := $P}|Cs], #{p := P} = Cnts) ->
+    count_small(Cs, Cnts#{p := P + 1});
+count_small([#{control_char := $w}|Cs], #{w := W} = Cnts) ->
+    count_small(Cs, Cnts#{w := W + 1});
+count_small([#{control_char := $W}|Cs], #{w := W} = Cnts) ->
+    count_small(Cs, Cnts#{w := W + 1});
+count_small([#{control_char := $s}|Cs], #{w := W} = Cnts) ->
+    count_small(Cs, Cnts#{w := W + 1});
+count_small([S|Cs], #{other := Other} = Cnts) when is_list(S);
+                                                   is_binary(S) ->
+    count_small(Cs, Cnts#{other := Other + io_lib:chars_length(S)});
+count_small([C|Cs], #{other := Other} = Cnts) when is_integer(C) ->
+    count_small(Cs, Cnts#{other := Other + 1});
+count_small([], #{p := P, s := S, w := W, other := Other}) ->
+    {P, S, W, Other}.
+
+%% build_small([Control]) -> io_lib:chars().
+%%  Interpret the control structures, but only the small ones.
+%%  The big ones are saved for later.
+%% build_limited([Control], NumberOfPps, NumberOfLimited,
+%%               CharsLimit, Indentation)
 %%  Interpret the control structures. Count the number of print
 %%  remaining and only calculate indentation when necessary. Must also
 %%  be smart when calculating indentation for characters in format.
 
-build([#{control_char := C, args := As, width := F, adjust := Ad,
-         precision := P, pad_char := Pad, encoding := Enc,
-         strings := Str} | Cs], Pc0, I) ->
-    S = control(C, As, F, Ad, P, Pad, Enc, Str, I),
-    Pc1 = decr_pc(C, Pc0),
+build_small([#{control_char := C, args := As, width := F, adjust := Ad,
+               precision := P, pad_char := Pad, encoding := Enc}=CC | Cs]) ->
+    case control_small(C, As, F, Ad, P, Pad, Enc) of
+        not_small -> [CC | build_small(Cs)];
+        S -> lists:flatten(S) ++ build_small(Cs)
+    end;
+build_small([C|Cs]) -> [C|build_small(Cs)];
+build_small([]) -> [].
+
+build_limited([#{control_char := C, args := As, width := F, adjust := Ad,
+                 precision := P, pad_char := Pad, encoding := Enc,
+                 strings := Str} | Cs], NumOfPs0, Count0, MaxLen0, I) ->
+    MaxChars = if
+                   MaxLen0 < 0 -> MaxLen0;
+                   true -> MaxLen0 div Count0
+               end,
+    S = control_limited(C, As, F, Ad, P, Pad, Enc, Str, MaxChars, I),
+    NumOfPs = decr_pc(C, NumOfPs0),
+    Count = Count0 - 1,
+    MaxLen = if
+                 MaxLen0 < 0 -> % optimization
+                     MaxLen0;
+                 true ->
+                     Len = io_lib:chars_length(S),
+                     sub(MaxLen0, Len)
+             end,
     if
-	Pc1 > 0 -> [S|build(Cs, Pc1, indentation(S, I))];
-	true -> [S|build(Cs, Pc1, I)]
+	NumOfPs > 0 -> [S|build_limited(Cs, NumOfPs, Count,
+                                        MaxLen, indentation(S, I))];
+	true -> [S|build_limited(Cs, NumOfPs, Count, MaxLen, I)]
     end;
-build([$\n|Cs], Pc, _I) -> [$\n|build(Cs, Pc, 0)];
-build([$\t|Cs], Pc, I) -> [$\t|build(Cs, Pc, ((I + 8) div 8) * 8)];
-build([C|Cs], Pc, I) -> [C|build(Cs, Pc, I+1)];
-build([], _Pc, _I) -> [].
+build_limited([$\n|Cs], NumOfPs, Count, MaxLen, _I) ->
+    [$\n|build_limited(Cs, NumOfPs, Count, MaxLen, 0)];
+build_limited([$\t|Cs], NumOfPs, Count, MaxLen, I) ->
+    [$\t|build_limited(Cs, NumOfPs, Count, MaxLen, ((I + 8) div 8) * 8)];
+build_limited([C|Cs], NumOfPs, Count, MaxLen, I) ->
+    [C|build_limited(Cs, NumOfPs, Count, MaxLen, I+1)];
+build_limited([], _, _, _, _) -> [].
 
 decr_pc($p, Pc) -> Pc - 1;
 decr_pc($P, Pc) -> Pc - 1;
 decr_pc(_, Pc) -> Pc.
 
-
 %%  Calculate the indentation of the end of a string given its start
 %%  indentation. We assume tabs at 8 cols.
 
 -spec indentation(String, StartIndent) -> integer() when
-      String :: eFmt:chars(),
+      String :: io_lib:chars(),
       StartIndent :: integer().
 
 indentation([$\n|Cs], _I) -> indentation(Cs, 0);
@@ -252,67 +321,74 @@ indentation([C|Cs], I) ->
     indentation(Cs, indentation(C, I));
 indentation([], I) -> I.
 
-%% control(FormatChar, [Argument], FieldWidth, Adjust, Precision, PadChar,
-%%	   Encoding, Indentation) -> String
-%%  This is the main dispatch function for the various formatting commands.
-%%  Field widths and precisions have already been calculated.
-
-control($w, [A], F, Adj, P, Pad, Enc, _Str, _I) ->
-    term(eFmt:write(A, [{depth,-1}, {encoding, Enc}]), F, Adj, P, Pad);
-control($p, [A], F, Adj, P, Pad, Enc, Str, I) ->
-    print(A, -1, F, Adj, P, Pad, Enc, Str, I);
-control($W, [A,Depth], F, Adj, P, Pad, Enc, _Str, _I) when is_integer(Depth) ->
-    term(eFmt:write(A, [{depth,Depth}, {encoding, Enc}]), F, Adj, P, Pad);
-control($P, [A,Depth], F, Adj, P, Pad, Enc, Str, I) when is_integer(Depth) ->
-    print(A, Depth, F, Adj, P, Pad, Enc, Str, I);
-control($s, [A], F, Adj, P, Pad, latin1, _Str, _I) when is_atom(A) ->
+%% control_small(FormatChar, [Argument], FieldWidth, Adjust, Precision,
+%%               PadChar, Encoding) -> String
+%% control_limited(FormatChar, [Argument], FieldWidth, Adjust, Precision,
+%%                 PadChar, Encoding, StringP, ChrsLim, Indentation) -> String
+%%  These are the dispatch functions for the various formatting controls.
+
+control_small($s, [A], F, Adj, P, Pad, latin1=Enc) when is_atom(A) ->
     L = iolist_to_chars(atom_to_list(A)),
-    string(L, F, Adj, P, Pad);
-control($s, [A], F, Adj, P, Pad, unicode, _Str, _I) when is_atom(A) ->
-    string(atom_to_list(A), F, Adj, P, Pad);
-control($s, [L0], F, Adj, P, Pad, latin1, _Str, _I) ->
-    L = iolist_to_chars(L0),
-    string(L, F, Adj, P, Pad);
-control($s, [L0], F, Adj, P, Pad, unicode, _Str, _I) ->
-    L = cdata_to_chars(L0),
-    uniconv(string(L, F, Adj, P, Pad));
-control($e, [A], F, Adj, P, Pad, _Enc, _Str, _I) when is_float(A) ->
+    string(L, F, Adj, P, Pad, Enc);
+control_small($s, [A], F, Adj, P, Pad, unicode=Enc) when is_atom(A) ->
+    string(atom_to_list(A), F, Adj, P, Pad, Enc);
+control_small($e, [A], F, Adj, P, Pad, _Enc) when is_float(A) ->
     fwrite_e(A, F, Adj, P, Pad);
-control($f, [A], F, Adj, P, Pad, _Enc, _Str, _I) when is_float(A) ->
+control_small($f, [A], F, Adj, P, Pad, _Enc) when is_float(A) ->
     fwrite_f(A, F, Adj, P, Pad);
-control($g, [A], F, Adj, P, Pad, _Enc, _Str, _I) when is_float(A) ->
+control_small($g, [A], F, Adj, P, Pad, _Enc) when is_float(A) ->
     fwrite_g(A, F, Adj, P, Pad);
-control($b, [A], F, Adj, P, Pad, _Enc, _Str, _I) when is_integer(A) ->
+control_small($b, [A], F, Adj, P, Pad, _Enc) when is_integer(A) ->
     unprefixed_integer(A, F, Adj, base(P), Pad, true);
-control($B, [A], F, Adj, P, Pad, _Enc, _Str, _I) when is_integer(A) ->
+control_small($B, [A], F, Adj, P, Pad, _Enc) when is_integer(A) ->
     unprefixed_integer(A, F, Adj, base(P), Pad, false);
-control($x, [A,Prefix], F, Adj, P, Pad, _Enc, _Str, _I) when is_integer(A),
-                                                 is_atom(Prefix) ->
+control_small($x, [A,Prefix], F, Adj, P, Pad, _Enc) when is_integer(A),
+                                                         is_atom(Prefix) ->
     prefixed_integer(A, F, Adj, base(P), Pad, atom_to_list(Prefix), true);
-control($x, [A,Prefix], F, Adj, P, Pad, _Enc, _Str, _I) when is_integer(A) ->
-    true = eFmt:deep_char_list(Prefix), %Check if Prefix a character list
+control_small($x, [A,Prefix], F, Adj, P, Pad, _Enc) when is_integer(A) ->
+    true = io_lib:deep_char_list(Prefix), %Check if Prefix a character list
     prefixed_integer(A, F, Adj, base(P), Pad, Prefix, true);
-control($X, [A,Prefix], F, Adj, P, Pad, _Enc, _Str, _I) when is_integer(A),
-                                                 is_atom(Prefix) ->
+control_small($X, [A,Prefix], F, Adj, P, Pad, _Enc) when is_integer(A),
+                                                         is_atom(Prefix) ->
     prefixed_integer(A, F, Adj, base(P), Pad, atom_to_list(Prefix), false);
-control($X, [A,Prefix], F, Adj, P, Pad, _Enc, _Str, _I) when is_integer(A) ->
-    true = eFmt:deep_char_list(Prefix), %Check if Prefix a character list
+control_small($X, [A,Prefix], F, Adj, P, Pad, _Enc) when is_integer(A) ->
+    true = io_lib:deep_char_list(Prefix), %Check if Prefix a character list
     prefixed_integer(A, F, Adj, base(P), Pad, Prefix, false);
-control($+, [A], F, Adj, P, Pad, _Enc, _Str, _I) when is_integer(A) ->
+control_small($+, [A], F, Adj, P, Pad, _Enc) when is_integer(A) ->
     Base = base(P),
     Prefix = [integer_to_list(Base), $#],
     prefixed_integer(A, F, Adj, Base, Pad, Prefix, true);
-control($#, [A], F, Adj, P, Pad, _Enc, _Str, _I) when is_integer(A) ->
+control_small($#, [A], F, Adj, P, Pad, _Enc) when is_integer(A) ->
     Base = base(P),
     Prefix = [integer_to_list(Base), $#],
     prefixed_integer(A, F, Adj, Base, Pad, Prefix, false);
-control($c, [A], F, Adj, P, Pad, unicode, _Str, _I) when is_integer(A) ->
+control_small($c, [A], F, Adj, P, Pad, unicode) when is_integer(A) ->
     char(A, F, Adj, P, Pad);
-control($c, [A], F, Adj, P, Pad, _Enc, _Str, _I) when is_integer(A) ->
+control_small($c, [A], F, Adj, P, Pad, _Enc) when is_integer(A) ->
     char(A band 255, F, Adj, P, Pad);
-control($~, [], F, Adj, P, Pad, _Enc, _Str, _I) -> char($~, F, Adj, P, Pad);
-control($n, [], F, Adj, P, Pad, _Enc, _Str, _I) -> newline(F, Adj, P, Pad);
-control($i, [_A], _F, _Adj, _P, _Pad, _Enc, _Str, _I) -> [].
+control_small($~, [], F, Adj, P, Pad, _Enc) -> char($~, F, Adj, P, Pad);
+control_small($n, [], F, Adj, P, Pad, _Enc) -> newline(F, Adj, P, Pad);
+control_small($i, [_A], _F, _Adj, _P, _Pad, _Enc) -> [];
+control_small(_C, _As, _F, _Adj, _P, _Pad, _Enc) -> not_small.
+
+control_limited($s, [L0], F, Adj, P, Pad, latin1=Enc, _Str, CL, _I) ->
+    L = iolist_to_chars(L0, F, CL),
+    string(L, limit_field(F, CL), Adj, P, Pad, Enc);
+control_limited($s, [L0], F, Adj, P, Pad, unicode=Enc, _Str, CL, _I) ->
+    L = cdata_to_chars(L0, F, CL),
+    uniconv(string(L, limit_field(F, CL), Adj, P, Pad, Enc));
+control_limited($w, [A], F, Adj, P, Pad, Enc, _Str, CL, _I) ->
+    Chars = io_lib:write(A, [{depth, -1}, {encoding, Enc}, {chars_limit, CL}]),
+    term(Chars, F, Adj, P, Pad);
+control_limited($p, [A], F, Adj, P, Pad, Enc, Str, CL, I) ->
+    print(A, -1, F, Adj, P, Pad, Enc, Str, CL, I);
+control_limited($W, [A,Depth], F, Adj, P, Pad, Enc, _Str, CL, _I)
+           when is_integer(Depth) ->
+    Chars = io_lib:write(A, [{depth, Depth}, {encoding, Enc}, {chars_limit, CL}]),
+    term(Chars, F, Adj, P, Pad);
+control_limited($P, [A,Depth], F, Adj, P, Pad, Enc, Str, CL, I)
+           when is_integer(Depth) ->
+    print(A, Depth, F, Adj, P, Pad, Enc, Str, CL, I).
 
 -ifdef(UNICODE_AS_BINARIES).
 uniconv(C) ->
@@ -335,7 +411,7 @@ base(B) when is_integer(B) ->
 term(T, none, _Adj, none, _Pad) -> T;
 term(T, none, Adj, P, Pad) -> term(T, P, Adj, P, Pad);
 term(T, F, Adj, P0, Pad) ->
-    L = lists:flatlength(T),
+    L = io_lib:chars_length(T),
     P = erlang:min(L, case P0 of none -> F; _ -> min(P0, F) end),
     if
 	L > P ->
@@ -349,12 +425,13 @@ term(T, F, Adj, P0, Pad) ->
 %% Print a term. Field width sets maximum line length, Precision sets
 %% initial indentation.
 
-print(T, D, none, Adj, P, Pad, E, Str, I) ->
-    print(T, D, 80, Adj, P, Pad, E, Str, I);
-print(T, D, F, Adj, none, Pad, E, Str, I) ->
-    print(T, D, F, Adj, I+1, Pad, E, Str, I);
-print(T, D, F, right, P, _Pad, Enc, Str, _I) ->
-    Options = [{column, P},
+print(T, D, none, Adj, P, Pad, E, Str, ChLim, I) ->
+    print(T, D, 80, Adj, P, Pad, E, Str, ChLim, I);
+print(T, D, F, Adj, none, Pad, E, Str, ChLim, I) ->
+    print(T, D, F, Adj, I+1, Pad, E, Str, ChLim, I);
+print(T, D, F, right, P, _Pad, Enc, Str, ChLim, _I) ->
+    Options = [{chars_limit, ChLim},
+               {column, P},
                {line_length, F},
                {depth, D},
                {encoding, Enc},
@@ -380,7 +457,7 @@ float_e(_Fl, {Ds,E}, P) ->
 	{Fs,false} -> [Fs|float_exp(E-1)]
     end.
 
-%% float_man([Digit], Icount, Dcount) -> {[Chars],CarryFlag}.
+%% float_man([Digit], Icount, Dcount) -> {[Char],CarryFlag}.
 %%  Generate the characters in the mantissa from the digits with Icount
 %%  characters before the '.' and Dcount decimals. Handle carry and let
 %%  caller decide what to do at top.
@@ -395,7 +472,7 @@ float_man([D|Ds], I, Dc) ->
 	{Cs,false} -> {[D|Cs],false}
     end;
 float_man([], I, Dc) ->				%Pad with 0's
-    {string:chars($0, I, [$.|string:chars($0, Dc)]),false}.
+    {lists:duplicate(I, $0) ++ [$.|lists:duplicate(Dc, $0)],false}.
 
 float_man([D|_], 0) when D >= $5 -> {[],true};
 float_man([_|_], 0) -> {[],false};
@@ -405,7 +482,7 @@ float_man([D|Ds], Dc) ->
 	{Cs,true} -> {[D+1|Cs],false}; 
 	{Cs,false} -> {[D|Cs],false}
     end;
-float_man([], Dc) -> {string:chars($0, Dc),false}.	%Pad with 0's
+float_man([], Dc) -> {lists:duplicate(Dc, $0),false}.	%Pad with 0's
 
 %% float_exp(Exponent) -> [Char].
 %%  Generate the exponent of a floating point number. Always include sign.
@@ -429,7 +506,7 @@ fwrite_f(Fl, F, Adj, P, Pad) when P >= 1 ->
 float_f(Fl, Fd, P) when Fl < 0.0 ->
     [$-|float_f(-Fl, Fd, P)];
 float_f(Fl, {Ds,E}, P) when E =< 0 ->
-    float_f(Fl, {string:chars($0, -E+1, Ds),1}, P);	%Prepend enough 0's
+    float_f(Fl, {lists:duplicate(-E+1, $0)++Ds,1}, P);	%Prepend enough 0's
 float_f(_Fl, {Ds,E}, P) ->
     case float_man(Ds, E, P) of
 	{Fs,true} -> "1" ++ Fs;			%Handle carry
@@ -641,7 +718,10 @@ fwrite_g(Fl, F, Adj, P, Pad) when P >= 1 ->
     end.
 
 
-%% iolist_to_chars(iolist()) -> deep_char_list()
+iolist_to_chars(Cs, F, CharsLimit) when CharsLimit < 0; CharsLimit >= F ->
+    iolist_to_chars(Cs);
+iolist_to_chars(Cs, _, CharsLimit) ->
+    limit_iolist_to_chars(Cs, sub(CharsLimit, 3), [], normal). % three dots
 
 iolist_to_chars([C|Cs]) when is_integer(C), C >= $\000, C =< $\377 ->
     [C | iolist_to_chars(Cs)];
@@ -652,12 +732,34 @@ iolist_to_chars([]) ->
 iolist_to_chars(B) when is_binary(B) ->
     binary_to_list(B).
 
-%% cdata() :: clist() | cbinary()
-%% clist() ::  maybe_improper_list(char() | cbinary() | clist(),
-%%                                 cbinary() | nil())
-%% cbinary() :: unicode:unicode_binary() | unicode:latin1_binary()
+limit_iolist_to_chars(Cs, 0, S, normal) ->
+    L = limit_iolist_to_chars(Cs, 4, S, final),
+    case iolist_size(L) of
+        N when N < 4 -> L;
+        4 -> "..."
+    end;
+limit_iolist_to_chars(_Cs, 0, _S, final) -> [];
+limit_iolist_to_chars([C|Cs], Limit, S, Mode) when C >= $\000, C =< $\377 ->
+    [C | limit_iolist_to_chars(Cs, Limit - 1, S, Mode)];
+limit_iolist_to_chars([I|Cs], Limit, S, Mode) ->
+    limit_iolist_to_chars(I, Limit, [Cs|S], Mode);
+limit_iolist_to_chars([], _Limit, [], _Mode) ->
+    [];
+limit_iolist_to_chars([], Limit, [Cs|S], Mode) ->
+    limit_iolist_to_chars(Cs, Limit, S, Mode);
+limit_iolist_to_chars(B, Limit, S, Mode) when is_binary(B) ->
+    case byte_size(B) of
+        Sz when Sz > Limit ->
+            {B1, B2} = split_binary(B, Limit),
+            [binary_to_list(B1) | limit_iolist_to_chars(B2, 0, S, Mode)];
+        Sz ->
+            [binary_to_list(B) | limit_iolist_to_chars([], Limit-Sz, S, Mode)]
+    end.
 
-%% cdata_to_chars(cdata()) -> eFmt:deep_char_list()
+cdata_to_chars(Cs, F, CharsLimit) when CharsLimit < 0; CharsLimit >= F ->
+    cdata_to_chars(Cs);
+cdata_to_chars(Cs, _, CharsLimit) ->
+    limit_cdata_to_chars(Cs, sub(CharsLimit, 3), normal). % three dots
 
 cdata_to_chars([C|Cs]) when is_integer(C), C >= $\000 ->
     [C | cdata_to_chars(Cs)];
@@ -671,32 +773,58 @@ cdata_to_chars(B) when is_binary(B) ->
         _ -> binary_to_list(B)
     end.
 
+limit_cdata_to_chars(Cs, 0, normal) ->
+    L = limit_cdata_to_chars(Cs, 4, final),
+    case string:length(L) of
+        N when N < 4 -> L;
+        4 -> "..."
+    end;
+limit_cdata_to_chars(_Cs, 0, final) -> [];
+limit_cdata_to_chars(Cs, Limit, Mode) ->
+    case string:next_grapheme(Cs) of
+        {error, <<C,Cs1/binary>>} ->
+            %% This is how ~ts handles Latin1 binaries with option
+            %% chars_limit.
+            [C | limit_cdata_to_chars(Cs1, Limit - 1, Mode)];
+        {error, [C|Cs1]} -> % not all versions of module string return this
+            [C | limit_cdata_to_chars(Cs1, Limit - 1, Mode)];
+        [] ->
+            [];
+        [GC|Cs1] ->
+            [GC | limit_cdata_to_chars(Cs1, Limit - 1, Mode)]
+    end.
+
+limit_field(F, CharsLimit) when CharsLimit < 0; F =:= none ->
+    F;
+limit_field(F, CharsLimit) ->
+    max(3, min(F, CharsLimit)).
+
 %% string(String, Field, Adjust, Precision, PadChar)
 
-string(S, none, _Adj, none, _Pad) -> S;
-string(S, F, Adj, none, Pad) ->
-    string_field(S, F, Adj, lists:flatlength(S), Pad);
-string(S, none, _Adj, P, Pad) ->
-    string_field(S, P, left, lists:flatlength(S), Pad);
-string(S, F, Adj, P, Pad) when F >= P ->
-    N = lists:flatlength(S),
+string(S, none, _Adj, none, _Pad, _Enc) -> S;
+string(S, F, Adj, none, Pad, Enc) ->
+    string_field(S, F, Adj, io_lib:chars_length(S), Pad, Enc);
+string(S, none, _Adj, P, Pad, Enc) ->
+    string_field(S, P, left, io_lib:chars_length(S), Pad, Enc);
+string(S, F, Adj, P, Pad, Enc) when F >= P ->
+    N = io_lib:chars_length(S),
     if F > P ->
 	    if N > P ->
-		    adjust(flat_trunc(S, P), chars(Pad, F-P), Adj);
+		    adjust(flat_trunc(S, P, Enc), chars(Pad, F-P), Adj);
 	       N < P ->
 		    adjust([S|chars(Pad, P-N)], chars(Pad, F-P), Adj);
 	       true -> % N == P
 		    adjust(S, chars(Pad, F-P), Adj)
 	    end;
        true -> % F == P
-	    string_field(S, F, Adj, N, Pad)
+	    string_field(S, F, Adj, N, Pad, Enc)
     end.
 
-string_field(S, F, _Adj, N, _Pad) when N > F ->
-    flat_trunc(S, F);
-string_field(S, F, Adj, N, Pad) when N < F ->
+string_field(S, F, _Adj, N, _Pad, Enc) when N > F ->
+    flat_trunc(S, F, Enc);
+string_field(S, F, Adj, N, Pad, _Enc) when N < F ->
     adjust(S, chars(Pad, F-N), Adj);
-string_field(S, _, _, _, _) -> % N == F
+string_field(S, _, _, _, _, _) -> % N == F
     S.
 
 %% unprefixed_integer(Int, Field, Adjust, Base, PadChar, Lowercase)
@@ -748,21 +876,13 @@ adjust(Data, Pad, right) -> [Pad|Data].
 
 %% Flatten and truncate a deep list to at most N elements.
 
-flat_trunc(List, N) when is_integer(N), N >= 0 ->
-    flat_trunc(List, N, [], []).
-
-flat_trunc(L, 0, _, R) when is_list(L) ->
-    lists:reverse(R);
-flat_trunc([H|T], N, S, R) when is_list(H) ->
-    flat_trunc(H, N, [T|S], R);
-flat_trunc([H|T], N, S, R) ->
-    flat_trunc(T, N-1, S, [H|R]);
-flat_trunc([], N, [H|S], R) ->
-    flat_trunc(H, N, S, R);
-flat_trunc([], _, [], R) ->
-    lists:reverse(R).
+flat_trunc(List, N, latin1) when is_integer(N), N >= 0 ->
+    {S, _} = lists:split(N, lists:flatten(List)),
+    S;
+flat_trunc(List, N, unicode) when is_integer(N), N >= 0 ->
+    string:slice(List, 0, N).
 
-%% A deep version of string:chars/2,3
+%% A deep version of lists:duplicate/2
 
 chars(_C, 0) ->
     [];
@@ -795,3 +915,15 @@ lowercase([H|T]) ->
     [H|lowercase(T)];
 lowercase([]) ->
     [].
+
+%% Make sure T does change sign.
+sub(T, _) when T < 0 -> T;
+sub(T, E) when T >= E -> T - E;
+sub(_, _) -> 0.
+
+get_option(Key, TupleList, Default) ->
+    case lists:keyfind(Key, 1, TupleList) of
+	false -> Default;
+	{Key, Value} -> Value;
+	_ -> Default
+    end.