{"id":1558,"date":"2012-09-17T20:58:42","date_gmt":"2012-09-17T16:58:42","guid":{"rendered":"https:\/\/blog.alwawee.ru\/?p=1558"},"modified":"2012-09-18T15:12:01","modified_gmt":"2012-09-18T11:12:01","slug":"how-to-change-string-encoding-from-koi8-r-to-utf8-in-objective-c","status":"publish","type":"post","link":"https:\/\/blog.alwawee.ru\/?p=1558","title":{"rendered":"How to Change String Encoding from KOI8-R to UTF8 in Objective-C"},"content":{"rendered":"

KOI8-R is an 8-bit character encoding, designed to cover Russian, which uses the Cyrillic alphabet. I was getting a fileName from IMAP in this encoding and wanted to convert it to normal readable UTF-8.<\/p>\n

My question concerning this issue in stackoverflow was banned<\/a>. I had to solve this myself and spent quite a bit of time. <\/p>\n

There is one solution, that works for many encodings – to use CFString methods<\/a>:
\n

<br \/>\n\u2013 (NSString*)decodeKOI8R:(NSString*)stringToDecode {<\/p>\n<p>    CFStringRef aCFString = CFStringCreateWithCString(NULL, [stringToDecode UTF8String], kCFStringEncodingKOI8_R);<br \/>\n    NSString *decodedString = (__bridge NSString*)aCFString;<\/p>\n<p>    return decodedString;<br \/>\n}<br \/>\n<\/code><\/pre><\/p>\n
But for some reason it worked for UTF-7 but didn’t for KOI8-R. <\/p>\n
I searched Google for hours, but couldn’t find a solution. Suddenly, I found a solution in MailCore CTBareAttachment class method, called decodedFilename. <\/p>\n
This is ObjC code of that method:
\n
<br \/>\n-(NSString*)decodedName {<br \/>\n    return MailCoreDecodeMIMEPhrase((char *)[self.name UTF8String]);<br \/>\n}<br \/>\n<\/code><\/pre><\/p>\n
This is a C language method, that converts char* to the NSString with a proper encoding.
\n
<br \/>\nNSString *MailCoreDecodeMIMEPhrase(char *data) {<br \/>\n    int err;<br \/>\n    size_t currToken = 0;<br \/>\n    char *decodedSubject;<br \/>\n    NSString *result;<\/p>\n<p>    if (*data != \u2018\\0\u2019) {<br \/>\n        err = mailmime_encoded_phrase_parse(DEST_CHARSET, data, strlen(data),<br \/>\n                                            &currToken, DEST_CHARSET, &decodedSubject);<\/p>\n<p>        if (err != MAILIMF_NO_ERROR) {<br \/>\n            if (decodedSubject == NULL)<br \/>\n                free(decodedSubject);<br \/>\n            return nil;<br \/>\n        }<br \/>\n    } else {<br \/>\n        return @\u201d\u201d;<br \/>\n    }<\/p>\n<p>    result = [NSString stringWithCString:decodedSubject encoding:NSUTF8StringEncoding];<br \/>\n    free(decodedSubject);<br \/>\n    return result;<br \/>\n}<br \/>\n<\/code><\/pre><\/p>\n
Here
\n
<br \/>\n#define DEST_CHARSET \u201cUTF-8\u201d<br \/>\n<\/code><\/pre><\/p>\n
and mailmime_encoded_phrase_parse is a pretty complex method, that is not easy even to copy paste here. So, this problem seems to have no easy solution, except using this C method. Actually this method parses a phrase and calls decoding C method for each word. And I ended up using it.<\/p>\n","protected":false},"excerpt":{"rendered":"
KOI8-R is an 8-bit character encoding, designed to cover Russian, which uses the Cyrillic alphabet. I was getting a fileName from IMAP in this encoding and wanted to convert it to normal readable UTF-8. My question concerning this issue in stackoverflow was banned. I had to solve this myself and spent quite a bit of […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-1558","post","type-post","status-publish","format-standard","hentry","category-ios"],"yoast_head":"\nHow to Change String Encoding from KOI8-R to UTF8 in Objective-C - Denis Kutlubaev<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/blog.alwawee.ru\/?p=1558\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"How to Change String Encoding from KOI8-R to UTF8 in Objective-C - Denis Kutlubaev\" \/>\n<meta property=\"og:description\" content=\"KOI8-R is an 8-bit character encoding, designed to cover Russian, which uses the Cyrillic alphabet. 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