nsCStringEncoding 编辑

The nsCStringEncoding enumeration describes the set of character encodings understood by the NS_CStringToUTF16 and NS_UTF16ToCString functions.

NS_CSTRING_ENCODING_ASCII: Conversion between ASCII and UTF-16 assumes that all bytes in the source string are 7-bit ASCII and can be inflated to UTF-16 by inserting null bytes. Reverse conversion is done by truncating every other byte. The conversion may result in loss and/or corruption of information if the strings do not strictly contain ASCII data.
NS_CSTRING_ENCODING_UTF8: Conversion between UTF-8 and UTF-16 is non-lossy.
NS_CSTRING_ENCODING_NATIVE_FILESYSTEM: Conversion from UTF-16 to the native filesystem charset may result in a loss of information. No attempt is made to protect against data loss in this case. The native filesystem charset applies to strings passed to the "Native" method variants on nsIFile and nsILocalFile.