前阵子问了这个问题
现在自己总结了一点,跟大家分享
windows下转码用MultiByteToWideChar和WideCharToMultiByte这两个函数
在你得到UTF16的编码后，要将其转成内码需要参数codepage代码页，用他将UTF16编码和内码对应起来进行转码
但是我们不知道用什么codepage(当你的UTF16中有多种语种的时候更麻烦)
所以要看Unicode Subset Bitfields来确定他的codepage，下表是我从MSDN上找到的
Bit Unicode subrange Description
0 0020 - 007e Basic Latin
1 00a0 - 00ff Latin-1 Supplement
2 0100 - 017f Latin Extended-A
3 0180 - 024f Latin Extended-B
4 0250 - 02af IPA Extensions
5 02b0 - 02ff Spacing Modifier Letters
6 0300 - 036f Combining Diacritical Marks
7 0370 - 03ff Basic Greek
8 Reserved
9 0400 - 04ff Cyrillic
10 0530 - 058f Armenian
11 0590 - 05ff Basic Hebrew
12 Reserved
13 0600 - 06ff Basic Arabic
14 Reserved
15 0900 - 097f Devanagari
16 0980 - 09ff Bengali
17 0a00 - 0a7f Gurmukhi
18 0a80 - 0aff Gujarati
19 0b00 - 0b7f Oriya
20 0b80 - 0bff Tamil
21 0c00 - 0c7f Telugu
22 0c80 - 0cff Kannada
23 0d00 - 0d7f Malayalam
24 0e00 - 0e7f Thai
25 0e80 - 0eff Lao
26 10a0 - 10ff Basic Georgian
27 Reserved
28 1100 - 11ff Hangul Jamo
29 1e00 - 1eff Latin Extended Additional
30 1f00 - 1fff Greek Extended
31 2000 - 206f General Punctuation
32 2070 - 209f Subscripts and Superscripts
33 20a0 - 20cf Currency Symbols
34 20d0 - 20ff Combining Diacritical Marks for Symbols
35 2100 - 214f Letter-like Symbols
36 2150 - 218f Number Forms
37 2190 - 21ff Arrows
38 2200 - 22ff Mathematical Operators
39 2300 - 23ff Miscellaneous Technical
40 2400 - 243f Control Pictures
41 2440 - 245f Optical Character Recognition
42 2460 - 24ff Enclosed Alphanumerics
43 2500 - 257f Box Drawing
44 2580 - 259f Block Elements
45 25a0 - 25ff Geometric Shapes
46 2600 - 26ff Miscellaneous Symbols
47 2700 - 27bf Dingbats
48 3000 - 303f Chinese, Japanese, and Korean (CJK) Symbols and Punctuation
49 3040 - 309f Hiragana
50 30a0 - 30ff Katakana
51 3100 - 312f31a0 - 31bf Bopomofo Extended Bopomofo
52 3130 - 318f Hangul Compatibility Jamo
53 3190 - 319f CJK Miscellaneous
54 3200 - 32ff Enclosed CJK Letters and Months
55 3300 - 33ff CJK Compatibility
56 ac00 - d7a3 Hangul
57 d800 - dfff Surrogates. Note that setting this bit implies that there is at least one codepoint beyond the Basic Multilingual Plane that is supported by this font.
58 Reserved
59 4e00 - 9fff2e80 - 2eff2f00 - 2fdf2ff0 - 2fff3400 - 4dbf CJK Unified IdeographsCJK Radicals SupplementKangxi RadicalsIdeographic DescriptionCJK Unified Ideograph Extension A
60 e000 - f8ff Private Use Area
61 f900 - faff CJK Compatibility Ideographs
62 fb00 - fb4f Alphabetic Presentation Forms
63 fb50 - fdff Arabic Presentation Forms-A
64 fe20 - fe2f Combining Half Marks
65 fe30 - fe4f CJK Compatibility Forms
66 fe50 - fe6f Small Form Variants
67 fe70 - fefe Arabic Presentation Forms-B
68 ff00 - ffef Halfwidth and Fullwidth Forms
69 fff0 - fffd Specials
70 0f00 - 0fcf Tibetan
71 0700 - 074f Syriac
72 0780 - 07bf Thaana
73 0d80 - 0dff Sinhala
74 1000 - 109f Myanmar
75 1200 - 12bf Ethiopic
76 13a0 - 13ff Cherokee
77 1400 - 14df Canadian Aboriginal Syllabics
78 1680 - 169f Ogham
79 16a0 - 16ff Runic
80 1780 - 17ff Khmer
81 1800 - 18af Mongolian
82 2800 - 28ff Braille
83 a000 - a48c Yi Yi Radicals
84-122 Reserved
123 Windows 2000/XP: Layout progress: horizontal from right to left
124 Windows 2000/XP: Layout progress: vertical before horizontal
125 Windows 2000/XP: Layout progress: vertical bottom to top
126 Reserved; must be 0
127 Reserved; must be 1
下表是主要的codepage
ANSI Code-Page Identifiers
Identifier Meaning
874 Thai
932 Japanese
936 Chinese (PRC, Singapore)
949 Korean
950 Chinese (Taiwan; Hong Kong SAR, PRC)
1200 Unicode (BMP of ISO 10646)
1250 Windows 3.1 Eastern European
1251 Windows 3.1 Cyrillic
1252 Windows 3.1 Latin 1 (US, Western Europe)
1253 Windows 3.1 Greek
1254 Windows 3.1 Turkish
1255 Hebrew
1256 Arabic
1257 Baltic
可以通过EnumSystemCodePages来枚举codepage
看起来很复杂，两个表似乎很难对应~~
自己根据一些资料经过实验总结了一部分
Unicode subrange Description Codepage
0x00-0x007F Basic Latin 0(CP_ACP)
0x7F-0x00FF Latin-1 Supplement 1252
0x0100-0x017F Latin Extended-A 1250
0x0180-0x024F Latin Extended-B ???
0x0370-0x03FF Basic Greek 1253
0x0E00-0x0E7F Thai 874
0x0590-0x05FF Basic Hebrew 1255
0x0600-0x07FF Basic Arabic 1256
也就只能如此了
LINUX下转码
在LINUX下转码的时候我找到了iconv族函数，用起来倒也简单
先打开iconv_t iconv_open(const char *tocode, const char *fromcode);
再转码size_t iconv(iconv_t cd,
char **inbuf, size_t *inbytesleft,
char **outbuf, size_t *outbytesleft);
最后关 int iconv_close(iconv_t cd);
尤其需要注意的是iconv_open的参数，两个code很容易让人出错。
这里的code和windows下的codepage很象
可以iconv –list这个命令来显示他所有的code
简单的可以用windows的codepage前加个CP，
例如 codepage是1250 code是“CP1250”
虽然简单但我还是为我的马虎（两个code下反了）付出了时间的代价
还有一个问题，我还没找到答案
一般在调用iconv的时候inbuf是char*的，他里面存放数据的顺序是先低位后高位
假如“尽”gb2312编码是0xBEA1在inbuf中应该存成
inbuf[0] = 0xBE;inbuf[1] = 0xA1;
但当编码为UTF16的时候，进iconv的inbuf的顺序是先高位后低位
例如“尽” UTF16编码是0x5C3D 在 inbuf中存成了
inbuf[0] = 0x3D;inbuf[1] = 0x5C;
搞不明白为什么，big endian small endian和CPU有关，这里又算怎么一回事~~只好把这部分的unicode挑出来了。
