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
10 using namespace Scintilla;
11
12 namespace Scintilla {
13
DBCSIsLeadByte(int codePage,char ch)14 bool 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
42 }
43