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author | Erlang/OTP <otp@erlang.org> | 2009-11-20 14:54:40 +0000 |
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committer | Erlang/OTP <otp@erlang.org> | 2009-11-20 14:54:40 +0000 |
commit | 84adefa331c4159d432d22840663c38f155cd4c1 (patch) | |
tree | bff9a9c66adda4df2106dfd0e5c053ab182a12bd /lib/stdlib/src/io_lib_format.erl | |
download | otp-84adefa331c4159d432d22840663c38f155cd4c1.tar.gz otp-84adefa331c4159d432d22840663c38f155cd4c1.tar.bz2 otp-84adefa331c4159d432d22840663c38f155cd4c1.zip |
The R13B03 release.OTP_R13B03
Diffstat (limited to 'lib/stdlib/src/io_lib_format.erl')
-rw-r--r-- | lib/stdlib/src/io_lib_format.erl | 678 |
1 files changed, 678 insertions, 0 deletions
diff --git a/lib/stdlib/src/io_lib_format.erl b/lib/stdlib/src/io_lib_format.erl new file mode 100644 index 0000000000..eb1885021d --- /dev/null +++ b/lib/stdlib/src/io_lib_format.erl @@ -0,0 +1,678 @@ +%% +%% %CopyrightBegin% +%% +%% Copyright Ericsson AB 1996-2009. All Rights Reserved. +%% +%% The contents of this file are subject to the Erlang Public License, +%% Version 1.1, (the "License"); you may not use this file except in +%% compliance with the License. You should have received a copy of the +%% Erlang Public License along with this software. If not, it can be +%% retrieved online at http://www.erlang.org/. +%% +%% Software distributed under the License is distributed on an "AS IS" +%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See +%% the License for the specific language governing rights and limitations +%% under the License. +%% +%% %CopyrightEnd% +%% +-module(io_lib_format). + +%% Formatting functions of io library. + +-export([fwrite/2,fwrite_g/1,indentation/2]). + +%% fwrite(Format, ArgList) -> [Char]. +%% Format the arguments in ArgList after string Format. Just generate +%% an error if there is an error in the arguments. +%% +%% To do the printing command correctly we need to calculate the +%% current indentation for everything before it. This may be very +%% expensive, especially when it is not needed, so we first determine +%% if, and for how long, we need to calculate the indentations. We do +%% this by first collecting all the control sequences and +%% corresponding arguments, then counting the print sequences and +%% then building the output. This method has some drawbacks, it does +%% two passes over the format string and creates more temporary data, +%% and it also splits the handling of the control characters into two +%% parts. + +fwrite(Format, Args) when is_atom(Format) -> + fwrite(atom_to_list(Format), Args); +fwrite(Format, Args) when is_binary(Format) -> + fwrite(binary_to_list(Format), Args); +fwrite(Format, Args) -> + Cs = collect(Format, Args), + Pc = pcount(Cs), + build(Cs, Pc, 0). + +collect([$~|Fmt0], Args0) -> + {C,Fmt1,Args1} = collect_cseq(Fmt0, Args0), + [C|collect(Fmt1, Args1)]; +collect([C|Fmt], Args) -> + [C|collect(Fmt, Args)]; +collect([], []) -> []. + +collect_cseq(Fmt0, Args0) -> + {F,Ad,Fmt1,Args1} = field_width(Fmt0, Args0), + {P,Fmt2,Args2} = precision(Fmt1, Args1), + {Pad,Fmt3,Args3} = pad_char(Fmt2, Args2), + {Encoding,Fmt4,Args4} = encoding(Fmt3, Args3), + {C,As,Fmt5,Args5} = collect_cc(Fmt4, Args4), + {{C,As,F,Ad,P,Pad,Encoding},Fmt5,Args5}. + +encoding([$t|Fmt],Args) -> + {unicode,Fmt,Args}; +encoding(Fmt,Args) -> + {latin1,Fmt,Args}. + +field_width([$-|Fmt0], Args0) -> + {F,Fmt,Args} = field_value(Fmt0, Args0), + field_width(-F, Fmt, Args); +field_width(Fmt0, Args0) -> + {F,Fmt,Args} = field_value(Fmt0, Args0), + field_width(F, Fmt, Args). + +field_width(F, Fmt, Args) when F < 0 -> + {-F,left,Fmt,Args}; +field_width(F, Fmt, Args) when F >= 0 -> + {F,right,Fmt,Args}. + +precision([$.|Fmt], Args) -> + field_value(Fmt, Args); +precision(Fmt, Args) -> + {none,Fmt,Args}. + +field_value([$*|Fmt], [A|Args]) when is_integer(A) -> + {A,Fmt,Args}; +field_value([C|Fmt], Args) when is_integer(C), C >= $0, C =< $9 -> + field_value([C|Fmt], Args, 0); +field_value(Fmt, Args) -> + {none,Fmt,Args}. + +field_value([C|Fmt], Args, F) when is_integer(C), C >= $0, C =< $9 -> + field_value(Fmt, Args, 10*F + (C - $0)); +field_value(Fmt, Args, F) -> %Default case + {F,Fmt,Args}. + +pad_char([$.,$*|Fmt], [Pad|Args]) -> {Pad,Fmt,Args}; +pad_char([$.,Pad|Fmt], Args) -> {Pad,Fmt,Args}; +pad_char(Fmt, Args) -> {$\s,Fmt,Args}. + +%% collect_cc([FormatChar], [Argument]) -> +%% {Control,[ControlArg],[FormatChar],[Arg]}. +%% Here we collect the argments for each control character. +%% Be explicit to cause failure early. + +collect_cc([$w|Fmt], [A|Args]) -> {$w,[A],Fmt,Args}; +collect_cc([$p|Fmt], [A|Args]) -> {$p,[A],Fmt,Args}; +collect_cc([$W|Fmt], [A,Depth|Args]) -> {$W,[A,Depth],Fmt,Args}; +collect_cc([$P|Fmt], [A,Depth|Args]) -> {$P,[A,Depth],Fmt,Args}; +collect_cc([$s|Fmt], [A|Args]) -> {$s,[A],Fmt,Args}; +collect_cc([$e|Fmt], [A|Args]) -> {$e,[A],Fmt,Args}; +collect_cc([$f|Fmt], [A|Args]) -> {$f,[A],Fmt,Args}; +collect_cc([$g|Fmt], [A|Args]) -> {$g,[A],Fmt,Args}; +collect_cc([$b|Fmt], [A|Args]) -> {$b,[A],Fmt,Args}; +collect_cc([$B|Fmt], [A|Args]) -> {$B,[A],Fmt,Args}; +collect_cc([$x|Fmt], [A,Prefix|Args]) -> {$x,[A,Prefix],Fmt,Args}; +collect_cc([$X|Fmt], [A,Prefix|Args]) -> {$X,[A,Prefix],Fmt,Args}; +collect_cc([$+|Fmt], [A|Args]) -> {$+,[A],Fmt,Args}; +collect_cc([$#|Fmt], [A|Args]) -> {$#,[A],Fmt,Args}; +collect_cc([$c|Fmt], [A|Args]) -> {$c,[A],Fmt,Args}; +collect_cc([$~|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]) -> {$i,[A],Fmt,Args}. + +%% pcount([ControlC]) -> Count. +%% Count the number of print requests. + +pcount(Cs) -> pcount(Cs, 0). + +pcount([{$p,_As,_F,_Ad,_P,_Pad,_Enc}|Cs], Acc) -> pcount(Cs, Acc+1); +pcount([{$P,_As,_F,_Ad,_P,_Pad,_Enc}|Cs], Acc) -> pcount(Cs, Acc+1); +pcount([_|Cs], Acc) -> pcount(Cs, Acc); +pcount([], Acc) -> Acc. + +%% build([Control], Pc, Indentation) -> [Char]. +%% Interpret the control structures. Count the number of print +%% remaining and only calculate indentation when necessary. Must also +%% be smart when calculating indentation for characters in format. + +build([{C,As,F,Ad,P,Pad,Enc}|Cs], Pc0, I) -> + S = control(C, As, F, Ad, P, Pad, Enc, I), + Pc1 = decr_pc(C, Pc0), + if + Pc1 > 0 -> [S|build(Cs, Pc1, indentation(S, I))]; + true -> [S|build(Cs, Pc1, I)] + end; +build([$\n|Cs], Pc, _I) -> [$\n|build(Cs, Pc, 0)]; +build([$\t|Cs], Pc, I) -> [$\t|build(Cs, Pc, ((I + 8) div 8) * 8)]; +build([C|Cs], Pc, I) -> [C|build(Cs, Pc, I+1)]; +build([], _Pc, _I) -> []. + +decr_pc($p, Pc) -> Pc - 1; +decr_pc($P, Pc) -> Pc - 1; +decr_pc(_, Pc) -> Pc. + +%% indentation([Char], Indentation) -> Indentation. +%% Calculate the indentation of the end of a string given its start +%% indentation. We assume tabs at 8 cols. + +indentation([$\n|Cs], _I) -> indentation(Cs, 0); +indentation([$\t|Cs], I) -> indentation(Cs, ((I + 8) div 8) * 8); +indentation([C|Cs], I) when is_integer(C) -> + indentation(Cs, I+1); +indentation([C|Cs], I) -> + indentation(Cs, indentation(C, I)); +indentation([], I) -> I. + +%% control(FormatChar, [Argument], FieldWidth, Adjust, Precision, PadChar, +%% Indentation) -> +%% [Char] +%% This is the main dispatch function for the various formatting commands. +%% Field widths and precisions have already been calculated. + +control($w, [A], F, Adj, P, Pad, _Enc,_I) -> + term(io_lib:write(A, -1), F, Adj, P, Pad); +control($p, [A], F, Adj, P, Pad, _Enc, I) -> + print(A, -1, F, Adj, P, Pad, I); +control($W, [A,Depth], F, Adj, P, Pad, _Enc, _I) when is_integer(Depth) -> + term(io_lib:write(A, Depth), F, Adj, P, Pad); +control($P, [A,Depth], F, Adj, P, Pad, _Enc, I) when is_integer(Depth) -> + print(A, Depth, F, Adj, P, Pad, I); +control($s, [A], F, Adj, P, Pad, _Enc, _I) when is_atom(A) -> + string(atom_to_list(A), F, Adj, P, Pad); +control($s, [L0], F, Adj, P, Pad, latin1, _I) -> + L = iolist_to_chars(L0), + string(L, F, Adj, P, Pad); +control($s, [L0], F, Adj, P, Pad, unicode, _I) -> + L = unicode:characters_to_list(L0), + uniconv(string(L, F, Adj, P, Pad)); +control($e, [A], F, Adj, P, Pad, _Enc, _I) when is_float(A) -> + fwrite_e(A, F, Adj, P, Pad); +control($f, [A], F, Adj, P, Pad, _Enc, _I) when is_float(A) -> + fwrite_f(A, F, Adj, P, Pad); +control($g, [A], F, Adj, P, Pad, _Enc, _I) when is_float(A) -> + fwrite_g(A, F, Adj, P, Pad); +control($b, [A], F, Adj, P, Pad, _Enc, _I) when is_integer(A) -> + unprefixed_integer(A, F, Adj, base(P), Pad, true); +control($B, [A], F, Adj, P, Pad, _Enc, _I) when is_integer(A) -> + unprefixed_integer(A, F, Adj, base(P), Pad, false); +control($x, [A,Prefix], F, Adj, P, Pad, _Enc, _I) when is_integer(A), + is_atom(Prefix) -> + prefixed_integer(A, F, Adj, base(P), Pad, atom_to_list(Prefix), true); +control($x, [A,Prefix], F, Adj, P, Pad, _Enc, _I) when is_integer(A) -> + true = io_lib:deep_char_list(Prefix), %Check if Prefix a character list + prefixed_integer(A, F, Adj, base(P), Pad, Prefix, true); +control($X, [A,Prefix], F, Adj, P, Pad, _Enc, _I) when is_integer(A), + is_atom(Prefix) -> + prefixed_integer(A, F, Adj, base(P), Pad, atom_to_list(Prefix), false); +control($X, [A,Prefix], F, Adj, P, Pad, _Enc, _I) when is_integer(A) -> + true = io_lib:deep_char_list(Prefix), %Check if Prefix a character list + prefixed_integer(A, F, Adj, base(P), Pad, Prefix, false); +control($+, [A], F, Adj, P, Pad, _Enc, _I) 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, _I) 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, _I) when is_integer(A) -> + char(A, F, Adj, P, Pad); +control($c, [A], F, Adj, P, Pad, _Enc, _I) when is_integer(A) -> + char(A band 255, F, Adj, P, Pad); +control($~, [], F, Adj, P, Pad, _Enc, _I) -> char($~, F, Adj, P, Pad); +control($n, [], F, Adj, P, Pad, _Enc, _I) -> newline(F, Adj, P, Pad); +control($i, [_A], _F, _Adj, _P, _Pad, _Enc, _I) -> []. + +-ifdef(UNICODE_AS_BINARIES). +uniconv(C) -> + unicode:characters_to_binary(C,unicode). +-else. +uniconv(C) -> + C. +-endif. +%% Default integer base +base(none) -> + 10; +base(B) when is_integer(B) -> + B. + +%% term(TermList, Field, Adjust, Precision, PadChar) +%% Output the characters in a term. +%% Adjust the characters within the field if length less than Max padding +%% with PadChar. + +term(T, none, _Adj, none, _Pad) -> T; +term(T, none, Adj, P, Pad) -> term(T, P, Adj, P, Pad); +term(T, F, Adj, P0, Pad) -> + L = lists:flatlength(T), + P = case P0 of none -> erlang:min(L, F); _ -> P0 end, + if + L > P -> + adjust(chars($*, P), chars(Pad, F-P), Adj); + F >= P -> + adjust(T, chars(Pad, F-L), Adj) + end. + +%% print(Term, Depth, Field, Adjust, Precision, PadChar, Indentation) +%% Print a term. + +print(T, D, none, Adj, P, Pad, I) -> print(T, D, 80, Adj, P, Pad, I); +print(T, D, F, Adj, none, Pad, I) -> print(T, D, F, Adj, I+1, Pad, I); +print(T, D, F, right, P, _Pad, _I) -> + io_lib_pretty:print(T, P, F, D). + +%% fwrite_e(Float, Field, Adjust, Precision, PadChar) + +fwrite_e(Fl, none, Adj, none, Pad) -> %Default values + fwrite_e(Fl, none, Adj, 6, Pad); +fwrite_e(Fl, none, _Adj, P, _Pad) when P >= 2 -> + float_e(Fl, float_data(Fl), P); +fwrite_e(Fl, F, Adj, none, Pad) -> + fwrite_e(Fl, F, Adj, 6, Pad); +fwrite_e(Fl, F, Adj, P, Pad) when P >= 2 -> + term(float_e(Fl, float_data(Fl), P), F, Adj, F, Pad). + +float_e(Fl, Fd, P) when Fl < 0.0 -> %Negative numbers + [$-|float_e(-Fl, Fd, P)]; +float_e(_Fl, {Ds,E}, P) -> + case float_man(Ds, 1, P-1) of + {[$0|Fs],true} -> [[$1|Fs]|float_exp(E)]; + {Fs,false} -> [Fs|float_exp(E-1)] + end. + +%% float_man([Digit], Icount, Dcount) -> {[Chars],CarryFlag}. +%% Generate the characters in the mantissa from the digits with Icount +%% characters before the '.' and Dcount decimals. Handle carry and let +%% caller decide what to do at top. + +float_man(Ds, 0, Dc) -> + {Cs,C} = float_man(Ds, Dc), + {[$.|Cs],C}; +float_man([D|Ds], I, Dc) -> + case float_man(Ds, I-1, Dc) of + {Cs,true} when D =:= $9 -> {[$0|Cs],true}; + {Cs,true} -> {[D+1|Cs],false}; + {Cs,false} -> {[D|Cs],false} + end; +float_man([], I, Dc) -> %Pad with 0's + {string:chars($0, I, [$.|string:chars($0, Dc)]),false}. + +float_man([D|_], 0) when D >= $5 -> {[],true}; +float_man([_|_], 0) -> {[],false}; +float_man([D|Ds], Dc) -> + case float_man(Ds, Dc-1) of + {Cs,true} when D =:= $9 -> {[$0|Cs],true}; + {Cs,true} -> {[D+1|Cs],false}; + {Cs,false} -> {[D|Cs],false} + end; +float_man([], Dc) -> {string:chars($0, Dc),false}. %Pad with 0's + +%% float_exp(Exponent) -> [Char]. +%% Generate the exponent of a floating point number. Always include sign. + +float_exp(E) when E >= 0 -> + [$e,$+|integer_to_list(E)]; +float_exp(E) -> + [$e|integer_to_list(E)]. + +%% fwrite_f(FloatData, Field, Adjust, Precision, PadChar) + +fwrite_f(Fl, none, Adj, none, Pad) -> %Default values + fwrite_f(Fl, none, Adj, 6, Pad); +fwrite_f(Fl, none, _Adj, P, _Pad) when P >= 1 -> + float_f(Fl, float_data(Fl), P); +fwrite_f(Fl, F, Adj, none, Pad) -> + fwrite_f(Fl, F, Adj, 6, Pad); +fwrite_f(Fl, F, Adj, P, Pad) when P >= 1 -> + term(float_f(Fl, float_data(Fl), P), F, Adj, F, Pad). + +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($0, -E+1, Ds),1}, P); %Prepend enough 0's +float_f(_Fl, {Ds,E}, P) -> + case float_man(Ds, E, P) of + {Fs,true} -> "1" ++ Fs; %Handle carry + {Fs,false} -> Fs + end. + +%% float_data([FloatChar]) -> {[Digit],Exponent} + +float_data(Fl) -> + float_data(float_to_list(Fl), []). + +float_data([$e|E], Ds) -> + {lists:reverse(Ds),list_to_integer(E)+1}; +float_data([D|Cs], Ds) when D >= $0, D =< $9 -> + float_data(Cs, [D|Ds]); +float_data([_|Cs], Ds) -> + float_data(Cs, Ds). + +%% fwrite_g(Float) +%% Writes the shortest, correctly rounded string that converts +%% to Float when read back with list_to_float/1. +%% +%% See also "Printing Floating-Point Numbers Quickly and Accurately" +%% in Proceedings of the SIGPLAN '96 Conference on Programming +%% Language Design and Implementation. + +fwrite_g(0.0) -> + "0.0"; +fwrite_g(Float) when is_float(Float) -> + {Frac, Exp} = mantissa_exponent(Float), + {Place, Digits} = fwrite_g_1(Float, Exp, Frac), + R = insert_decimal(Place, [$0 + D || D <- Digits]), + [$- || true <- [Float < 0.0]] ++ R. + +-define(BIG_POW, (1 bsl 52)). +-define(MIN_EXP, (-1074)). + +mantissa_exponent(F) -> + case <<F:64/float>> of + <<_S:1, 0:11, M:52>> -> % denormalized + E = log2floor(M), + {M bsl (53 - E), E - 52 - 1075}; + <<_S:1, BE:11, M:52>> when BE < 2047 -> + {M + ?BIG_POW, BE - 1075} + end. + +fwrite_g_1(Float, Exp, Frac) -> + Round = (Frac band 1) =:= 0, + if + Exp >= 0 -> + BExp = 1 bsl Exp, + if + Frac =:= ?BIG_POW -> + scale(Frac * BExp * 4, 4, BExp * 2, BExp, + Round, Round, Float); + true -> + scale(Frac * BExp * 2, 2, BExp, BExp, + Round, Round, Float) + end; + Exp < ?MIN_EXP -> + BExp = 1 bsl (?MIN_EXP - Exp), + scale(Frac * 2, 1 bsl (1 - Exp), BExp, BExp, + Round, Round, Float); + Exp > ?MIN_EXP, Frac =:= ?BIG_POW -> + scale(Frac * 4, 1 bsl (2 - Exp), 2, 1, + Round, Round, Float); + true -> + scale(Frac * 2, 1 bsl (1 - Exp), 1, 1, + Round, Round, Float) + end. + +scale(R, S, MPlus, MMinus, LowOk, HighOk, Float) -> + Est = int_ceil(math:log10(abs(Float)) - 1.0e-10), + %% Note that the scheme implementation uses a 326 element look-up + %% table for int_pow(10, N) where we do not. + if + Est >= 0 -> + fixup(R, S * int_pow(10, Est), MPlus, MMinus, Est, + LowOk, HighOk); + true -> + Scale = int_pow(10, -Est), + fixup(R * Scale, S, MPlus * Scale, MMinus * Scale, Est, + LowOk, HighOk) + end. + +fixup(R, S, MPlus, MMinus, K, LowOk, HighOk) -> + TooLow = if + HighOk -> R + MPlus >= S; + true -> R + MPlus > S + end, + case TooLow of + true -> + {K + 1, generate(R, S, MPlus, MMinus, LowOk, HighOk)}; + false -> + {K, generate(R * 10, S, MPlus * 10, MMinus * 10, LowOk, HighOk)} + end. + +generate(R0, S, MPlus, MMinus, LowOk, HighOk) -> + D = R0 div S, + R = R0 rem S, + TC1 = if + LowOk -> R =< MMinus; + true -> R < MMinus + end, + TC2 = if + HighOk -> R + MPlus >= S; + true -> R + MPlus > S + end, + case {TC1, TC2} of + {false, false} -> + [D | generate(R * 10, S, MPlus * 10, MMinus * 10, LowOk, HighOk)]; + {false, true} -> + [D + 1]; + {true, false} -> + [D]; + {true, true} when R * 2 < S -> + [D]; + {true, true} -> + [D + 1] + end. + +insert_decimal(0, S) -> + "0." ++ S; +insert_decimal(Place, S) -> + L = length(S), + if + Place < 0; + Place >= L -> + ExpL = integer_to_list(Place - 1), + ExpDot = if L =:= 1 -> 2; true -> 1 end, + ExpCost = length(ExpL) + 1 + ExpDot, + if + Place < 0 -> + if + 2 - Place =< ExpCost -> + "0." ++ lists:duplicate(-Place, $0) ++ S; + true -> + insert_exp(ExpL, S) + end; + true -> + if + Place - L + 2 =< ExpCost -> + S ++ lists:duplicate(Place - L, $0) ++ ".0"; + true -> + insert_exp(ExpL, S) + end + end; + true -> + {S0, S1} = lists:split(Place, S), + S0 ++ "." ++ S1 + end. + +insert_exp(ExpL, [C]) -> + [C] ++ ".0e" ++ ExpL; +insert_exp(ExpL, [C | S]) -> + [C] ++ "." ++ S ++ "e" ++ ExpL. + +int_ceil(X) when is_float(X) -> + T = trunc(X), + case (X - T) of + Neg when Neg < 0 -> T; + Pos when Pos > 0 -> T + 1; + _ -> T + end. + +int_pow(X, 0) when is_integer(X) -> + 1; +int_pow(X, N) when is_integer(X), is_integer(N), N > 0 -> + int_pow(X, N, 1). + +int_pow(X, N, R) when N < 2 -> + R * X; +int_pow(X, N, R) -> + int_pow(X * X, N bsr 1, case N band 1 of 1 -> R * X; 0 -> R end). + +log2floor(Int) when is_integer(Int), Int > 0 -> + log2floor(Int, 0). + +log2floor(0, N) -> + N; +log2floor(Int, N) -> + log2floor(Int bsr 1, 1 + N). + +%% fwrite_g(Float, Field, Adjust, Precision, PadChar) +%% Use the f form if Float is >= 0.1 and < 1.0e4, +%% and the prints correctly in the f form, else the e form. +%% Precision always means the # of significant digits. + +fwrite_g(Fl, F, Adj, none, Pad) -> + fwrite_g(Fl, F, Adj, 6, Pad); +fwrite_g(Fl, F, Adj, P, Pad) when P >= 1 -> + A = abs(Fl), + E = if A < 1.0e-1 -> -2; + A < 1.0e0 -> -1; + A < 1.0e1 -> 0; + A < 1.0e2 -> 1; + A < 1.0e3 -> 2; + A < 1.0e4 -> 3; + true -> fwrite_f + end, + if P =< 1, E =:= -1; + P-1 > E, E >= -1 -> + fwrite_f(Fl, F, Adj, P-1-E, Pad); + P =< 1 -> + fwrite_e(Fl, F, Adj, 2, Pad); + true -> + fwrite_e(Fl, F, Adj, P, Pad) + end. + + +%% iolist_to_chars(iolist()) -> deep_char_list() + +iolist_to_chars([C|Cs]) when is_integer(C), C >= $\000, C =< $\377 -> + [C | iolist_to_chars(Cs)]; +iolist_to_chars([I|Cs]) -> + [iolist_to_chars(I) | iolist_to_chars(Cs)]; +iolist_to_chars([]) -> + []; +iolist_to_chars(B) when is_binary(B) -> + binary_to_list(B). + +%% string(String, Field, Adjust, Precision, PadChar) + +string(S, none, _Adj, none, _Pad) -> S; +string(S, F, Adj, none, Pad) -> + N = lists:flatlength(S), + if N > F -> flat_trunc(S, F); + N =:= F -> S; + true -> adjust(S, chars(Pad, F-N), Adj) + end; +string(S, none, _Adj, P, Pad) -> + N = lists:flatlength(S), + if N > P -> flat_trunc(S, P); + N =:= P -> S; + true -> [S|chars(Pad, P-N)] + end; +string(S, F, Adj, F, Pad) -> + string(S, none, Adj, F, Pad); +string(S, F, Adj, P, Pad) when F > P -> + N = lists:flatlength(S), + if N > F -> flat_trunc(S, F); + N =:= F -> S; + N > P -> adjust(flat_trunc(S, P), chars(Pad, F-P), Adj); + N =:= P -> adjust(S, chars(Pad, F-P), Adj); + true -> adjust([S|chars(Pad, P-N)], chars(Pad, F-P), Adj) + end. + +%% unprefixed_integer(Int, Field, Adjust, Base, PadChar, Lowercase) +%% -> [Char]. + +unprefixed_integer(Int, F, Adj, Base, Pad, Lowercase) + when Base >= 2, Base =< 1+$Z-$A+10 -> + if Int < 0 -> + S = cond_lowercase(erlang:integer_to_list(-Int, Base), Lowercase), + term([$-|S], F, Adj, none, Pad); + true -> + S = cond_lowercase(erlang:integer_to_list(Int, Base), Lowercase), + term(S, F, Adj, none, Pad) + end. + +%% prefixed_integer(Int, Field, Adjust, Base, PadChar, Prefix, Lowercase) +%% -> [Char]. + +prefixed_integer(Int, F, Adj, Base, Pad, Prefix, Lowercase) + when Base >= 2, Base =< 1+$Z-$A+10 -> + if Int < 0 -> + S = cond_lowercase(erlang:integer_to_list(-Int, Base), Lowercase), + term([$-,Prefix|S], F, Adj, none, Pad); + true -> + S = cond_lowercase(erlang:integer_to_list(Int, Base), Lowercase), + term([Prefix|S], F, Adj, none, Pad) + end. + +%% char(Char, Field, Adjust, Precision, PadChar) -> [Char]. + +char(C, none, _Adj, none, _Pad) -> [C]; +char(C, F, _Adj, none, _Pad) -> chars(C, F); +char(C, none, _Adj, P, _Pad) -> chars(C, P); +char(C, F, Adj, P, Pad) when F >= P -> + adjust(chars(C, P), chars(Pad, F - P), Adj). + +%% newline(Field, Adjust, Precision, PadChar) -> [Char]. + +newline(none, _Adj, _P, _Pad) -> "\n"; +newline(F, right, _P, _Pad) -> chars($\n, F). + +%% +%% Utilities +%% + +adjust(Data, [], _) -> Data; +adjust(Data, Pad, left) -> [Data,Pad]; +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). + +%% A deep version of string:chars/2,3 + +chars(_C, 0) -> + []; +chars(C, 1) -> + [C]; +chars(C, 2) -> + [C,C]; +chars(C, 3) -> + [C,C,C]; +chars(C, N) when is_integer(N), (N band 1) =:= 0 -> + S = chars(C, N bsr 1), + [S|S]; +chars(C, N) when is_integer(N) -> + S = chars(C, N bsr 1), + [C,S|S]. + +%chars(C, N, Tail) -> +% [chars(C, N)|Tail]. + +%% Lowercase conversion + +cond_lowercase(String, true) -> + lowercase(String); +cond_lowercase(String,false) -> + String. + +lowercase([H|T]) when is_integer(H), H >= $A, H =< $Z -> + [(H-$A+$a)|lowercase(T)]; +lowercase([H|T]) -> + [H|lowercase(T)]; +lowercase([]) -> + []. |