1// Scintilla source code edit control
2/** @file DBCS.cxx
3 ** Functions to handle DBCS double byte encodings like Shift-JIS.
4 **/
5// Copyright 2017 by Neil Hodgson <neilh@scintilla.org>
6// The License.txt file describes the conditions under which this software may be distributed.
7
8#include "DBCS.h"
9
10using namespace Scintilla::Internal;
11
12namespace Scintilla::Internal {
13
14bool DBCSIsLeadByte(int codePage, char ch) noexcept {
15 // Byte ranges found in Wikipedia articles with relevant search strings in each case
16 const unsigned char uch = ch;
17 switch (codePage) {
18 case 932:
19 // Shift_jis
20 return ((uch >= 0x81) && (uch <= 0x9F)) ||
21 ((uch >= 0xE0) && (uch <= 0xFC));
22 // Lead bytes F0 to FC may be a Microsoft addition.
23 case 936:
24 // GBK
25 return (uch >= 0x81) && (uch <= 0xFE);
26 case 949:
27 // Korean Wansung KS C-5601-1987
28 return (uch >= 0x81) && (uch <= 0xFE);
29 case 950:
30 // Big5
31 return (uch >= 0x81) && (uch <= 0xFE);
32 case 1361:
33 // Korean Johab KS C-5601-1992
34 return
35 ((uch >= 0x84) && (uch <= 0xD3)) ||
36 ((uch >= 0xD8) && (uch <= 0xDE)) ||
37 ((uch >= 0xE0) && (uch <= 0xF9));
38 }
39 return false;
40}
41
42bool IsDBCSValidSingleByte(int codePage, int ch) noexcept {
43 switch (codePage) {
44 case 932:
45 return ch == 0x80
46 || (ch >= 0xA0 && ch <= 0xDF)
47 || (ch >= 0xFD);
48
49 default:
50 return false;
51 }
52}
53
54}
55