iconv C++ 实现 字符 (语言) 编码 转换

iconv是linux超强的字符编码转换工具，其提供命令行和源码两种方式可以使用。
在windows下如果想用，可能需要通过mingw ， 一个可能的组合是mingw +　code::blocks + gcc + windows.
不过没有试过，如果需要，值得一试。


1. iconv


  在LINUX上进行编码转换时,既可以利用iconv函数族编程实现,也可以利用iconv命令来实现,只不过后者是针对文件的,即将指定文件从一种编码转换为另一种编码。


  (1) 利用iconv函数族进行编码转换


  iconv函数族的头文件是iconv.h,使用前需包含之。
       ＃include <iconv.h>
  iconv函数族有三个函数,原型如下:
iconv_t iconv_open(const char *tocode, const char *fromcode);
    此函数说明将要进行哪两种编码的转换,tocode是目标编码,fromcode是原编码,该函数返回一个转换句柄,供以下两个函数使用。
size_t iconv(iconv_t cd,char **inbuf,size_t *inbytesleft,char **outbuf,size_t *outbytesleft);
    此函数从inbuf中读取字符,转换后输出到outbuf中,inbytesleft用以记录还未转换的字符数,outbytesleft用以记录输出缓冲的剩余空间。 
int iconv_close(iconv_t cd);
   此函数用于关闭转换句柄,释放资源。


 (2) 利用iconv命令进行编码转换


  iconv命令用于转换指定文件的编码,默认输出到标准输出设备,亦可指定输出文件。


  用法： iconv [选项...] [文件...]


  有如下选项可用:


输入/输出格式规范：
-f, --from-code=名称 原始文本编码
-t, --to-code=名称 输出编码


信息：
-l, --list 列举所有已知的字符集


输出控制：
-c 从输出中忽略无效的字符
-o, --output=FILE 输出文件
-s, --silent 关闭警告
--verbose 打印进度信息


-?, --help 给出该系统求助列表
--usage 给出简要的用法信息
-V, --version 打印程序版本号


例子:
iconv -f utf-8 -t gb2312 aaa.txt >bbb.txt
这个命令读取aaa.txt文件，从utf-8编码转换为gb2312编码,其输出定向到bbb.txt文件。




2.iconv实现通用语言编码转换(c++)
   可以实现对任意的两个iconv支持的语言编码做互相转换，比如GB2312, GBK, GB18030, UTF-8, UTF-16, BIG5等.
下面这段程序，非常的稳定，测试了超过10万行的数十种编码的文本的转换都没有出问题。 


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iconv.h>


#ifndef ICONV_CONST
# define ICONV_CONST const
#endif


/*!
 对字符串进行语言编码转换
 param from  原始编码，比如"GB2312",的按照iconv支持的写
 param to      转换的目的编码
 param save  转换后的数据保存到这个指针里，需要在外部分配内存
 param savelen 存储转换后数据的内存大小
 param src      原始需要转换的字符串
 param srclen    原始字符串长度
 */
int
convert(const char *from, const char *to, char* save, int savelen, char *src, int srclen)
{
    iconv_t cd;
    char   *inbuf = src;
    char *outbuf = save;
    size_t outbufsize = savelen;
    int status = 0;
    size_t  savesize = 0;
    size_t inbufsize = srclen;
    const char* inptr = inbuf;
    size_t      insize = inbufsize;
    char* outptr = outbuf;
    size_t outsize = outbufsize;
    
    cd = iconv_open(to, from);
    iconv(cd,NULL,NULL,NULL,NULL);
    if (inbufsize == 0) {
        status = -1;
        goto done;
    }
    while (insize > 0) {
        size_t res = iconv(cd,(ICONV_CONST char**)&inptr,&insize,&outptr,&outsize);
        if (outptr != outbuf) {
            int saved_errno = errno;
            int outsize = outptr - outbuf;
            strncpy(save+savesize, outbuf, outsize);
            errno = saved_errno;
        }
        if (res == (size_t)(-1)) {
            if (errno == EILSEQ) {
                int one = 1;
                iconvctl(cd,ICONV_SET_DISCARD_ILSEQ,&one);
                status = -3;
            } else if (errno == EINVAL) {
                if (inbufsize == 0) {
                    status = -4;
                    goto done;
                } else {
                    break;
                }
            } else if (errno == E2BIG) {
                status = -5;
                goto done;
            } else {
                status = -6;
                goto done;
            }
        }
    }
    status = strlen(save);
done:
    iconv_close(cd);
    return status;
}






附录：
所有已知的字符集
　　437, 500, 500V1, 850, 851, 852, 855, 856, 857, 860, 861, 862, 863, 864, 865, 　　866, 866NAV, 869, 874, 904, 1026, 1046, 1047, 8859_1, 8859_2, 8859_3, 8859_4, 　　8859_5, 8859_6, 8859_7, 8859_8, 8859_9, 10646-1:1993, 10646-1:1993/UCS4, 　　ANSI_X3.4-1968, ANSI_X3.4-1986, ANSI_X3.4, ANSI_X3.110-1983, ANSI_X3.110, 　　ARABIC, ARABIC7, ARMSCII-8, ASCII, ASMO-708, ASMO_449, BALTIC, BIG-5, 　　BIG-FIVE, BIG5-HKSCS, BIG5, BIG5HKSCS, BIGFIVE, BS_4730, CA, CN-BIG5, CN-GB, 　　CN, CP-AR, CP-GR, CP-HU, CP037, CP038, CP273, CP274, CP275, CP278, CP280, 　　CP281, CP282, CP284, CP285, CP290, CP297, CP367, CP420, CP423, CP424, CP437, 　　CP500, CP737, CP775, CP813, CP819, CP850, CP851, CP852, CP855, CP856, CP857, 　　CP860, CP861, CP862, CP863, CP864, CP865, CP866, CP866NAV, CP868, CP869, 　　CP870, CP871, CP874, CP875, CP880, CP891, CP903, CP904, CP905, CP912, CP915, 　　CP916, CP918, CP920, CP922, CP930, CP932, CP933, CP935, CP936, CP937, CP939, 　　CP949, CP950, CP1004, CP1026, CP1046, CP1047, CP1070, CP1079, CP1081, CP1084, 　　CP1089, CP1124, CP1125, CP1129, CP1132, CP1133, CP1160, CP1161, CP1162, 　　CP1163, CP1164, CP1250, CP1251, CP1252, CP1253, CP1254, CP1255, CP1256, 　　CP1257, CP1258, CP1361, CP10007, CPIBM861, CSA7-1, CSA7-2, CSASCII, 　　CSA_T500-1983, CSA_T500, CSA_Z243.4-1985-1, CSA_Z243.4-1985-2, 　　CSA_Z243.419851, CSA_Z243.419852, CSDECMCS, CSEBCDICATDE, CSEBCDICATDEA, 　　CSEBCDICCAFR, CSEBCDICDKNO, CSEBCDICDKNOA, CSEBCDICES, CSEBCDICESA, 　　CSEBCDICESS, CSEBCDICFISE, CSEBCDICFISEA, CSEBCDICFR, CSEBCDICIT, CSEBCDICPT, 　　CSEBCDICUK, CSEBCDICUS, CSEUCKR, CSEUCPKDFMTJAPANESE, CSGB2312, CSHPROMAN8, 　　CSIBM037, CSIBM038, CSIBM273, CSIBM274, CSIBM275, CSIBM277, CSIBM278, 　　CSIBM280, CSIBM281, CSIBM284, CSIBM285, CSIBM290, CSIBM297, CSIBM420, 　　CSIBM423, CSIBM424, CSIBM500, CSIBM851, CSIBM855, CSIBM856, CSIBM857, 　　CSIBM860, CSIBM863, CSIBM864, CSIBM865, CSIBM866, CSIBM868, CSIBM869, 　　CSIBM870, CSIBM871, CSIBM880, CSIBM891, CSIBM903, CSIBM904, CSIBM905, 　　CSIBM918, CSIBM922, CSIBM930, CSIBM932, CSIBM933, CSIBM935, CSIBM937, 　　CSIBM939, CSIBM943, CSIBM1026, CSIBM1124, CSIBM1129, CSIBM1132, CSIBM1133, 　　CSIBM1160, CSIBM1161, CSIBM1163, CSIBM1164, CSIBM11621162, 　　CSISO4UNITEDKINGDOM, CSISO10SWEDISH, CSISO11SWEDISHFORNAMES, 　　CSISO14JISC6220RO, CSISO15ITALIAN, CSISO16PORTUGESE, CSISO17SPANISH, 　　CSISO18GREEK7OLD, CSISO19LATINGREEK, CSISO21GERMAN, CSISO25FRENCH, 　　CSISO27LATINGREEK1, CSISO49INIS, CSISO50INIS8, CSISO51INISCYRILLIC, 　　CSISO58GB1988, CSISO60DANISHNORWEGIAN, CSISO60NORWEGIAN1, CSISO61NORWEGIAN2, 　　CSISO69FRENCH, CSISO84PORTUGUESE2, CSISO85SPANISH2, CSISO86HUNGARIAN, 　　CSISO88GREEK7, CSISO89ASMO449, CSISO90, CSISO92JISC62991984B, CSISO99NAPLPS, 　　CSISO103T618BIT, CSISO111ECMACYRILLIC, CSISO121CANADIAN1, CSISO122CANADIAN2, 　　CSISO139CSN369103, CSISO141JUSIB1002, CSISO143IECP271, CSISO150, 　　CSISO150GREEKCCITT, CSISO151CUBA, CSISO153GOST1976874, CSISO646DANISH, 　　CSISO2022CN, CSISO2022JP, CSISO2022JP2, CSISO2022KR, CSISO2033, 　　CSISO5427CYRILLIC, CSISO5427CYRILLIC1981, CSISO5428GREEK, CSISO10367BOX, 　　CSISOLATIN1, CSISOLATIN2, CSISOLATIN3, CSISOLATIN4, CSISOLATIN5, CSISOLATIN6, 　　CSISOLATINARABIC, CSISOLATINCYRILLIC, CSISOLATINGREEK, CSISOLATINHEBREW, 　　CSKOI8R, CSKSC5636, CSMACINTOSH, CSNATSDANO, CSNATSSEFI, CSN_369103, 　　CSPC8CODEPAGE437, CSPC775BALTIC, CSPC850MULTILINGUAL, CSPC862LATINHEBREW, 　　CSPCP852, CSSHIFTJIS, CSUCS4, CSUNICODE, CUBA, CWI-2, CWI, CYRILLIC, DE, 　　DEC-MCS, DEC, DECMCS, DIN_66003, DK, DS2089, DS_2089, E13B, EBCDIC-AT-DE-A, 　　EBCDIC-AT-DE, EBCDIC-BE, EBCDIC-BR, EBCDIC-CA-FR, EBCDIC-CP-AR1, 　　EBCDIC-CP-AR2, EBCDIC-CP-BE, EBCDIC-CP-CA, EBCDIC-CP-CH, EBCDIC-CP-DK, 　　EBCDIC-CP-ES, EBCDIC-CP-FI, EBCDIC-CP-FR, EBCDIC-CP-GB, EBCDIC-CP-GR, 　　EBCDIC-CP-HE, EBCDIC-CP-IS, EBCDIC-CP-IT, EBCDIC-CP-NL, EBCDIC-CP-NO, 　　EBCDIC-CP-ROECE, EBCDIC-CP-SE, EBCDIC-CP-TR, EBCDIC-CP-US, EBCDIC-CP-WT, 　　EBCDIC-CP-YU, EBCDIC-CYRILLIC, EBCDIC-DK-NO-A, EBCDIC-DK-NO, EBCDIC-ES-A, 　　EBCDIC-ES-S, EBCDIC-ES, EBCDIC-FI-SE-A, EBCDIC-FI-SE, EBCDIC-FR, 　　EBCDIC-GREEK, EBCDIC-INT, EBCDIC-INT1, EBCDIC-IS-FRISS, EBCDIC-IT, 　　EBCDIC-JP-E, EBCDIC-JP-KANA, EBCDIC-PT, EBCDIC-UK, EBCDIC-US, EBCDICATDE, 　　EBCDICATDEA, EBCDICCAFR, EBCDICDKNO, EBCDICDKNOA, EBCDICES, EBCDICESA, 　　EBCDICESS, EBCDICFISE, EBCDICFISEA, EBCDICFR, EBCDICISFRISS, EBCDICIT, 　　EBCDICPT, EBCDICUK, EBCDICUS, ECMA-114, ECMA-118, ECMA-128, ECMA-CYRILLIC, 　　ECMACYRILLIC, ELOT_928, ES, ES2, EUC-CN,EUC-JISX0213, EUC-JP, EUC-KR, 　　EUC-TW, EUCCN, EUCJP, EUCKR, EUCTW, FI, FR, GB, GB2312, GB13000, GB18030, 　　GBK, GB_1988-80, GB_198880, GEORGIAN-ACADEMY, GEORGIAN-PS, GOST_19768-74, 　　GOST_19768, GOST_1976874, GREEK-CCITT, GREEK, GREEK7-OLD, GREEK7, GREEK7OLD, 　　GREEK8, GREEKCCITT, HEBREW, HP-ROMAN8, HPROMAN8, HU, IBM-856, IBM-922, 　　IBM-930, IBM-932, IBM-933, IBM-935, IBM-937, IBM-939, IBM-943, IBM-1046, 　　IBM-1124, IBM-1129, IBM-1132, IBM-1133, IBM-1160, IBM-1161, IBM-1162, 　　IBM-1163, IBM-1164, IBM037, IBM038, IBM256, IBM273, IBM274, IBM275, IBM277, 　　IBM278, IBM280, IBM281, IBM284, IBM285, IBM290, IBM297, IBM367, IBM420, 　　IBM423, IBM424, IBM437, IBM500, IBM775, IBM813, IBM819, IBM848, IBM850, 　　IBM851, IBM852, IBM855, IBM856, IBM857, IBM860, IBM861, IBM862, IBM863, 　　IBM864, IBM865, IBM866, IBM866NAV, IBM868, IBM869, IBM870, IBM871, IBM874, 　　IBM875, IBM880, IBM891, IBM903, IBM904, IBM905, IBM912, IBM915, IBM916, 　　IBM918, IBM920, IBM922, IBM930, IBM932, IBM933, IBM935, IBM937, IBM939, 　　IBM943, IBM1004, IBM1026, IBM1046, IBM1047, IBM1089, IBM1124, IBM1129, 　　IBM1132, IBM1133, IBM1160, IBM1161, IBM1162, IBM1163, IBM1164, IEC_P27-1, 　　IEC_P271, INIS-8, INIS-CYRILLIC, INIS, INIS8, INISCYRILLIC, ISIRI-3342, 　　ISIRI3342, ISO-2022-CN-EXT, ISO-2022-CN, ISO-2022-JP-2, ISO-2022-JP-3, 　　ISO-2022-JP, ISO-2022-KR, ISO-8859-1, ISO-8859-2, ISO-8859-3, ISO-8859-4, 　　ISO-8859-5, ISO-8859-6, ISO-8859-7, ISO-8859-8, ISO-8859-9, ISO-8859-10, 　　ISO-8859-11, ISO-8859-13, ISO-8859-14, ISO-8859-15, ISO-8859-16, ISO-10646, 　　ISO-10646/UCS2, ISO-10646/UCS4, ISO-10646/UTF-8, ISO-10646/UTF8, ISO-CELTIC, 　　ISO-IR-4, ISO-IR-6, ISO-IR-8-1, ISO-IR-9-1, ISO-IR-10, ISO-IR-11, ISO-IR-14, 　　ISO-IR-15, ISO-IR-16, ISO-IR-17, ISO-IR-18, ISO-IR-19, ISO-IR-21, ISO-IR-25, 　　ISO-IR-27, ISO-IR-37, ISO-IR-49, ISO-IR-50, ISO-IR-51, ISO-IR-54, ISO-IR-55, 　　ISO-IR-57, ISO-IR-60, ISO-IR-61, ISO-IR-69, ISO-IR-84, ISO-IR-85, ISO-IR-86, 　　ISO-IR-88, ISO-IR-89, ISO-IR-90, ISO-IR-92, ISO-IR-98, ISO-IR-99, ISO-IR-100, 　　ISO-IR-101, ISO-IR-103, ISO-IR-109, ISO-IR-110, ISO-IR-111, ISO-IR-121, 　　ISO-IR-122, ISO-IR-126, ISO-IR-127, ISO-IR-138, ISO-IR-139, ISO-IR-141, 　　ISO-IR-143, ISO-IR-144, ISO-IR-148, ISO-IR-150, ISO-IR-151, ISO-IR-153, 　　ISO-IR-155, ISO-IR-156, ISO-IR-157, ISO-IR-166, ISO-IR-179, ISO-IR-193, 　　ISO-IR-197, ISO-IR-199, ISO-IR-203, ISO-IR-209, ISO-IR-226, ISO646-CA, 　　ISO646-CA2, ISO646-CN, ISO646-CU, ISO646-DE, ISO646-DK, ISO646-ES, 　　ISO646-ES2, ISO646-FI, ISO646-FR, ISO646-FR1, ISO646-GB, ISO646-HU, 　　ISO646-IT, ISO646-JP-OCR-B, ISO646-JP, ISO646-KR, ISO646-NO, ISO646-NO2, 　　ISO646-PT, ISO646-PT2, ISO646-SE, ISO646-SE2, ISO646-US, ISO646-YU, 　　ISO2022CN, ISO2022CNEXT, ISO2022JP, ISO2022JP2, ISO2022KR, ISO6937, 　　ISO8859-1, ISO8859-2, ISO8859-3, ISO8859-4, ISO8859-5, ISO8859-6, ISO8859-7, 　　ISO8859-8, ISO8859-9, ISO8859-10, ISO8859-11, ISO8859-13, ISO8859-14, 　　ISO8859-15, ISO8859-16, ISO88591, ISO88592, ISO88593, ISO88594, ISO88595, 　　ISO88596, ISO88597, ISO88598, ISO88599, ISO885910, ISO885911, ISO885913, 　　ISO885914, ISO885915, ISO885916, ISO_646.IRV:1991, ISO_2033-1983, ISO_2033, 　　ISO_5427-EXT, ISO_5427, ISO_5427:1981, ISO_5427EXT, ISO_5428, ISO_5428:1980, 　　ISO_6937-2, ISO_6937-2:1983, ISO_6937, ISO_6937:1992, ISO_8859-1, 　　ISO_8859-1:1987, ISO_8859-2, ISO_8859-2:1987, ISO_8859-3, ISO_8859-3:1988, 　　ISO_8859-4, ISO_8859-4:1988, ISO_8859-5, ISO_8859-5:1988, ISO_8859-6, 　　ISO_8859-6:1987, ISO_8859-7, ISO_8859-7:1987, ISO_8859-8, ISO_8859-8:1988, 　　ISO_8859-9, ISO_8859-9:1989, ISO_8859-10,ISO_8859-10:1992, ISO_8859-14, 　　ISO_8859-14:1998, ISO_8859-15:1998, ISO_9036, ISO_10367-BOX, ISO_10367BOX, 　　ISO_69372, IT, JIS_C6220-1969-RO, JIS_C6229-1984-B, JIS_C62201969RO, 　　JIS_C62291984B, JOHAB, JP-OCR-B, JP, JS, JUS_I.B1.002, KOI-7, KOI-8,KOI8-R, 　　KOI8-T, KOI8-U, KOI8, KOI8R, KOI8U, KSC5636, L1, L2, L3, L4, L5, L6, L7, L8, 　　L10, LATIN-GREEK-1, LATIN-GREEK, LATIN1, LATIN2, LATIN3, LATIN4, LATIN5, 　　LATIN6, LATIN7, LATIN8, LATIN10, LATINGREEK, LATINGREEK1, MAC-CYRILLIC, 　　MAC-IS, MAC-SAMI, MAC-UK, MAC, MACCYRILLIC, MACINTOSH, MACIS, MACUK, 　　MACUKRAINIAN, MS-ANSI, MS-ARAB, MS-CYRL, MS-EE, MS-GREEK, MS-HEBR, 　　MS-MAC-CYRILLIC, MS-TURK, MSCP949, MSCP1361, MSMACCYRILLIC, MSZ_7795.3, 　　MS_KANJI, NAPLPS, NATS-DANO, NATS-SEFI, NATSDANO, NATSSEFI, NC_NC0010, 　　NC_NC00-10, NC_NC00-10:81, NF_Z_62-010, NF_Z_62-010_(1973), NF_Z_62-010_1973, 　　NF_Z_62010, NF_Z_62010_1973, NO, NO2, NS_4551-1, NS_4551-2, NS_45511, 　　NS_45512, OS2LATIN1, OSF00010001, OSF00010002, OSF00010003, OSF00010004, 　　OSF00010005, OSF00010006, OSF00010007, OSF00010008, OSF00010009, OSF0001000A, 　　OSF00010020, OSF00010100, OSF00010101, OSF00010102, OSF00010104, OSF00010105, 　　OSF00010106, OSF00030010, OSF0004000A, OSF0005000A, OSF05010001, OSF100201A4, 　　OSF100201A8, OSF100201B5, OSF100201F4, OSF100203B5, OSF1002011C, OSF1002011D, 　　OSF1002035D, OSF1002035E, OSF1002035F, OSF1002036B, OSF1002037B, OSF10010001, 　　OSF10020025, OSF10020111, OSF10020115, OSF10020116, OSF10020118, OSF10020122, 　　OSF10020129, OSF10020352, OSF10020354, OSF10020357, OSF10020359, OSF10020360, 　　OSF10020364, OSF10020365, OSF10020366, OSF10020367, OSF10020370, OSF10020387, 　　OSF10020388, OSF10020396, OSF10020402, OSF10020417, PT, PT2, R8, ROMAN8, 　　RUSCII, SE, SE2, SEN_850200_B, SEN_850200_C, SHIFT-JIS, SHIFT_JIS, 　　SHIFT_JISX0213, SJIS, SS636127, ST_SEV_358-88, T.61-8BIT, T.61, T.618BIT, 　　TCVN-5712, TCVN, TCVN5712-1, TCVN5712-1:1993, TIS-620, TIS620-0, 　　TIS620.2529-1, TIS620.2533-0, TIS620, TS-5881, TSCII, UCS-2, UCS-2BE, 　　UCS-2LE, UCS-4, UCS-4BE, UCS-4LE, UCS2, UCS4, UHC, UJIS, UK, UNICODE, 　　UNICODEBIG, UNICODELITTLE, US-ASCII, US, UTF-7, UTF-8, UTF-16, UTF-16BE, 　　UTF-16LE, UTF-32, UTF-32BE, UTF-32LE, UTF7, UTF8, UTF16, UTF16BE, UTF16LE, 　　UTF32, UTF32BE, UTF32LE, VISCII, WCHAR_T, WIN-SAMI-2, WINBALTRIM, 　　WINDOWS-1250, WINDOWS-1251, WINDOWS-1252, WINDOWS-1253, WINDOWS-1254, 　　WINDOWS-1255, WINDOWS-1256, WINDOWS-1257, WINDOWS-1258, WINSAMI2, WS2, YU