c++ - In ICU UnicodeString what is the difference between countChar32() and length()? -

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from docs;

the length number of uchar code units in unicodestring. if want number of code points, please use countchar32().

and

count unicode code points in length uchar code units of string.

a code point may occupy either 1 or 2 uchar code units. counting code points involves reading code units.

from inclined think code point actual character , code unit 1 possible part of character.

for example.

say have unicode string like:

'foobar'

both length , countchar32 6. have string composed of 6 chars take full 32 bits encode length 12 countchar32 6.

is correct?

the 2 values differ if use characters out of base multilingual plane (bmp). these characters represented in utf-16 surrogate pairs. 2 16-bit characters make 1 logical character. if use of these, each pair counts one 32-bit character 2 elements of length.


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