public ReversedLinesFileReader()

in src/main/java/org/apache/commons/io/input/ReversedLinesFileReader.java [371:425]
41 lines of code
13 McCabe index (conditional complexity)

    public ReversedLinesFileReader(final Path file, final int blockSize, final Charset charset) throws IOException {
        this.blockSize = blockSize;
        this.charset = Charsets.toCharset(charset);

        // --- check & prepare encoding ---
        final CharsetEncoder charsetEncoder = this.charset.newEncoder();
        final float maxBytesPerChar = charsetEncoder.maxBytesPerChar();
        if (maxBytesPerChar == 1f || this.charset == StandardCharsets.UTF_8) {
            // all one byte encodings are no problem
            byteDecrement = 1;
        } else if (this.charset == Charset.forName("Shift_JIS") || // Same as for UTF-8
        // http://www.herongyang.com/Unicode/JIS-Shift-JIS-Encoding.html
                this.charset == Charset.forName("windows-31j") || // Windows code page 932 (Japanese)
                this.charset == Charset.forName("x-windows-949") || // Windows code page 949 (Korean)
                this.charset == Charset.forName("gbk") || // Windows code page 936 (Simplified Chinese)
                this.charset == Charset.forName("x-windows-950")) { // Windows code page 950 (Traditional Chinese)
            byteDecrement = 1;
        } else if (this.charset == StandardCharsets.UTF_16BE || this.charset == StandardCharsets.UTF_16LE) {
            // UTF-16 new line sequences are not allowed as second tuple of four byte
            // sequences,
            // however byte order has to be specified
            byteDecrement = 2;
        } else if (this.charset == StandardCharsets.UTF_16) {
            throw new UnsupportedEncodingException(
                    "For UTF-16, you need to specify the byte order (use UTF-16BE or " + "UTF-16LE)");
        } else {
            throw new UnsupportedEncodingException(
                    "Encoding " + charset + " is not supported yet (feel free to " + "submit a patch)");
        }

        // NOTE: The new line sequences are matched in the order given, so it is
        // important that \r\n is BEFORE \n
        this.newLineSequences = new byte[][] {
            StandardLineSeparator.CRLF.getBytes(this.charset),
            StandardLineSeparator.LF.getBytes(this.charset),
            StandardLineSeparator.CR.getBytes(this.charset)
        };

        this.avoidNewlineSplitBufferSize = newLineSequences[0].length;

        // Open file
        this.channel = Files.newByteChannel(file, StandardOpenOption.READ);
        this.totalByteLength = channel.size();
        int lastBlockLength = (int) (this.totalByteLength % blockSize);
        if (lastBlockLength > 0) {
            this.totalBlockCount = this.totalByteLength / blockSize + 1;
        } else {
            this.totalBlockCount = this.totalByteLength / blockSize;
            if (this.totalByteLength > 0) {
                lastBlockLength = blockSize;
            }
        }
        this.currentFilePart = new FilePart(totalBlockCount, lastBlockLength, null);

    }