question: private int matchNextHeader ( int i , String key ) { int size = _headerSize ; int length = key . length ( ) ; char [ ] keyBuf = _headerBuffer ; char [ ] toLowerAscii = _toLowerAscii ; for ( ; i < size ; i ++ ) { CharSegment header = _headerKeys [ i ] ; if ( header . length ( ) != length ) continue ; int offset = header . offset ( ) ; int j ; for ( j = 0 ; j < length ; j ++ ) { char a = key . charAt ( j ) ; char b = keyBuf [ offset + j ] ; if ( a == b ) { continue ; } else if ( toLowerAscii [ a ] != toLowerAscii [ b ] ) { break ; } } if ( j == length ) { return i ; } } return - 1 ; }
target:  Returns the index of the next header matching the key.