- The ISO 2022-JP encoder is now static as with all others; this is
slightly slower, but localises the encoder logic to its class
- Indexed encoders now cache pointer tables on first use, yielding
significant performance benefits
- Encoding multiple characters now uses fewer function calls, yielding
moderate performance benefits at the expense of slight complication
- array_flip() retains the last duplicate, when we need the first
- Indexes are now prepared with a list of first-duplicate code points
to search before flipping
- This affected only U+3000 in GBK
- Big5 did not use array_flip(), but its list of override code points
did not include U+2561; Big5 now flips like the others
- EUC-JP had a long list of errors, but this encoding was not
previously released
- Shift_JIS' indexes are probably not correct, still
- UTF-16 needs to restore dirtyEOF after seeking
- gb18030 now tracks errors like other non-synchronizing encodings
- gb18030 could produce null when asked for a character
