aboutsummaryrefslogtreecommitdiffstats
path: root/src/base/UTextEncoding.pas
blob: bb3d0f1a3d88d05ecef441fb5432bbf9c710012f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
{* UltraStar Deluxe - Karaoke Game
 *
 * UltraStar Deluxe is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING. If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 *}

unit UTextEncoding;

interface

{$IFDEF FPC}
  {$MODE Delphi}
{$ENDIF}

{$I switches.inc}

uses
  SysUtils,
  UUnicodeUtils;

type
  TEncoding = (
    encLocale,  // current locale (needs cwstring on linux)
    encUTF8,    // UTF-8
    encCP1250,  // Windows-1250 Central/Eastern Europe (used by Ultrastar)
    encCP1252   // Windows-1252 Western Europe (used by UltraStar Deluxe < 1.1)
  );

const
  UTF8_BOM: UTF8String = #$EF#$BB#$BF;

{**
 * Decodes Src encoded in SrcEncoding to a UTF-16 or UTF-8 encoded Dst string.
 * Returns true if the conversion was successful.
 *}
function DecodeString(const Src: RawByteString; out Dst: WideString; SrcEncoding: TEncoding): boolean; overload;
function DecodeString(const Src: RawByteString; SrcEncoding: TEncoding): WideString; overload;
function DecodeStringUTF8(const Src: RawByteString; out Dst: UTF8String; SrcEncoding: TEncoding): boolean; overload;
function DecodeStringUTF8(const Src: RawByteString; SrcEncoding: TEncoding): UTF8String; overload;

{**
 * Encodes the UTF-16 or UTF-8 encoded Src string to Dst using DstEncoding
 * Returns true if the conversion was successful.
 *}
function EncodeString(const Src: WideString; out Dst: RawByteString; DstEncoding: TEncoding): boolean; overload;
function EncodeString(const Src: WideString; DstEncoding: TEncoding): RawByteString; overload;
function EncodeStringUTF8(const Src: UTF8String; out Dst: RawByteString; DstEncoding: TEncoding): boolean; overload;
function EncodeStringUTF8(const Src: UTF8String; DstEncoding: TEncoding): RawByteString; overload;

{**
 * If Text starts with an UTF-8 BOM, the BOM is removed and true will
 * be returned.
 *}
function CheckReplaceUTF8BOM(var Text: RawByteString): boolean;

{**
 * Parses an encoding string to its TEncoding equivalent.
 * Surrounding whitespace and dashes ('-') are removed, the upper-cased
 * resulting value is then compared with TEncodingNames.
 * If the encoding was not found, the result is set to the Default encoding.
 *}
function ParseEncoding(const EncodingStr: AnsiString; Default: TEncoding): TEncoding;

{**
 * Returns the name of an encoding.
 *}
function EncodingName(Encoding: TEncoding): AnsiString;

implementation

uses
  StrUtils;

type
  IEncoder = interface
    function GetName(): AnsiString;
    function Encode(const InStr: UCS4String; out OutStr: RawByteString): boolean;
    function Decode(const InStr: RawByteString; out OutStr: UCS4String): boolean;
  end;

  TEncoder = class(TInterfacedObject, IEncoder)
  public
    function GetName(): AnsiString; virtual; abstract;
    function Encode(const InStr: UCS4String; out OutStr: RawByteString): boolean; virtual; abstract;
    function Decode(const InStr: RawByteString; out OutStr: UCS4String): boolean; virtual; abstract;
  end;

  TSingleByteEncoder = class(TEncoder)
  public
    function Encode(const InStr: UCS4String; out OutStr: RawByteString): boolean; override;
    function Decode(const InStr: RawByteString; out OutStr: UCS4String): boolean; override;
    function DecodeChar(InChr: AnsiChar; out OutChr: UCS4Char): boolean; virtual; abstract;
    function EncodeChar(InChr: UCS4Char; out OutChr: AnsiChar): boolean; virtual; abstract;
  end;

const
  ERROR_CHAR = '?';

var
  Encoders: array[TEncoding] of IEncoder;

function TSingleByteEncoder.Encode(const InStr: UCS4String; out OutStr: RawByteString): boolean;
var
  I: integer;
begin
  SetLength(OutStr, LengthUCS4(InStr));
  Result := true;
  for I := 1 to Length(OutStr) do
  begin
    if (not EncodeChar(InStr[I-1], OutStr[I])) then
      Result := false;
  end;
end;

function TSingleByteEncoder.Decode(const InStr: RawByteString; out OutStr: UCS4String): boolean;
var
  I: integer;
begin
  SetLength(OutStr, Length(InStr)+1);
  Result := true;
  for I := 1 to Length(InStr) do
  begin
    if (not DecodeChar(InStr[I], OutStr[I-1])) then
      Result := false;
  end;
  OutStr[High(OutStr)] := 0;
end;

function DecodeString(const Src: RawByteString; out Dst: WideString; SrcEncoding: TEncoding): boolean;
var
  DstUCS4: UCS4String;
begin
  Result := Encoders[SrcEncoding].Decode(Src, DstUCS4);
  Dst := UCS4StringToWideString(DstUCS4);
end;

function DecodeString(const Src: RawByteString; SrcEncoding: TEncoding): WideString;
begin
  DecodeString(Src, Result, SrcEncoding);
end;

function DecodeStringUTF8(const Src: RawByteString; out Dst: UTF8String; SrcEncoding: TEncoding): boolean;
var
  DstUCS4: UCS4String;
begin
  Result := Encoders[SrcEncoding].Decode(Src, DstUCS4);
  Dst := UCS4ToUTF8String(DstUCS4);
end;

function DecodeStringUTF8(const Src: RawByteString; SrcEncoding: TEncoding): UTF8String;
begin
  DecodeStringUTF8(Src, Result, SrcEncoding);
end;

function EncodeString(const Src: WideString; out Dst: RawByteString; DstEncoding: TEncoding): boolean;
begin
  Result := Encoders[DstEncoding].Encode(WideStringToUCS4String(Src), Dst);
end;

function EncodeString(const Src: WideString; DstEncoding: TEncoding): RawByteString;
begin
  EncodeString(Src, Result, DstEncoding);
end;

function EncodeStringUTF8(const Src: UTF8String; out Dst: RawByteString; DstEncoding: TEncoding): boolean;
begin
  Result := Encoders[DstEncoding].Encode(UTF8ToUCS4String(Src), Dst);
end;

function EncodeStringUTF8(const Src: UTF8String; DstEncoding: TEncoding): RawByteString;
begin
  EncodeStringUTF8(Src, Result, DstEncoding);
end;

function CheckReplaceUTF8BOM(var Text: RawByteString): boolean;
begin
  if AnsiStartsStr(UTF8_BOM, Text) then
  begin
    Text := Copy(Text, Length(UTF8_BOM)+1, Length(Text)-Length(UTF8_BOM));
    Result := true;
    Exit;
  end;
  Result := false;
end;

function ParseEncoding(const EncodingStr: AnsiString; Default: TEncoding): TEncoding;
var
  PrepStr: AnsiString; // prepared encoding string
  Encoding: TEncoding;
begin
  // remove surrounding whitespace, replace dashes, to upper case
  PrepStr := UpperCase(AnsiReplaceStr(Trim(EncodingStr), '-', ''));
  for Encoding := Low(TEncoding) to High(TEncoding) do
  begin
    if (Encoders[Encoding].GetName() = PrepStr) then
    begin
      Result := Encoding;
      Exit;
    end;
  end;
  Result := Default;
end;

function EncodingName(Encoding: TEncoding): AnsiString;
begin
  Result := Encoders[Encoding].GetName();
end;

{$I ../encoding/Locale.inc}
{$I ../encoding/UTF8.inc}
{$I ../encoding/CP1250.inc}
{$I ../encoding/CP1252.inc}

initialization
  Encoders[encLocale] := TEncoderLocale.Create;
  Encoders[encUTF8]   := TEncoderUTF8.Create;
  Encoders[encCP1250] := TEncoderCP1250.Create;
  Encoders[encCP1252] := TEncoderCP1252.Create;

end.