UnicodeString to char* (UTF-8)

views:

answers:

+1 Q:

UnicodeString to char* (UTF-8)

I am using the ICU library in C++ on OS X. All of my strings are UnicodeStrings, but I need to use system calls like fopen, fread and so forth. These functions take const char* or char* as arguments. I have read that OS X supports UTF-8 internally, so that all I need to do is convert my UnicodeString to UTF-8, but I don't know how to do that.

UnicodeString has a toUTF8() member function, but it returns a ByteSink. I've also found these examples: http://source.icu-project.org/repos/icu/icu/trunk/source/samples/ucnv/convsamp.cpp and read about using a converter, but I'm still confused. Any help would be much appreciated. Thank you!

+1 A:

call UnicodeString::extract(...) to extract into a char*, pass NULL for the converter to get the default converter (which is in the charset which your OS will be using).

Steven R. Loomis 2010-06-30 17:31:08

Thank you! That does work. I'm not sure about the destCapacity argument and the length of the UnicodeString. This code works: http://codepad.org/blaSP0ex but you'll notice I double the .length() of the UnicodeString manually to make up for the multibyte string. How can I make sure there is enough space in my char* dest?

Isaac 2010-06-30 18:55:54

http://icu-project.org/apiref/icu4c/classUnicodeString.html#125255f27efd817e38806d76d9567345It will return the length needed for the output string and a U_BUFFER_OVERFLOW_ERROR in status if there wasn't enough space. See http://userguide.icu-project.org/strings#TOC-Using-C-Strings:-NUL-Terminated-vs%2e

Steven R. Loomis 2010-07-01 00:04:13

Thank you. The documentation says that it's best to guess the size and if there's a buffer overflow error, then to call the extract function again with the length returned from the first call. I do that here: http://codepad.org/nyp5yJWB but the second call still fails, even though I provide it with the correct length returned from the first extract call. What am I doing wrong?

Isaac 2010-07-01 14:37:03

I forgot delete[] instead of delete, and I don't think I need sizeof (I use C usually), but those are minor details.

Isaac 2010-07-01 15:03:48

That's right, but you need to reset the error code after the failure. ICU functions just exit if the error is already set. http://userguide.icu-project.org/design#TOC-Error-Handling

Steven R. Loomis 2010-07-01 21:46:20

Thank you! Everything works now. I don't mean to keep pestering you, but it just seems like you're the only one who knows anything about ICU.

Isaac 2010-07-02 08:58:27

ansaurus

tags:

views:

answers:

UnicodeString to char* (UTF-8)

related questions