question: private int readCodepoint ( ) { @ SuppressWarnings ( "hiding" ) String css = this . css ; char ch = css . charAt ( pos ) ; if ( Character . isHighSurrogate ( ch ) && pos + 1 < cssLimit ) { char next = css . charAt ( pos + 1 ) ; if ( Character . isLowSurrogate ( next ) ) { ++ pos ; return 0x10000 + ( ( ( ch - 0xd800 ) << 10 ) | ( next - 0xdc00 ) ) ; } } return ch ; }
target:  Reads the codepoint at pos, leaving pos at the index of the last code unit.