/*-
 * Public Domain 2014-2015 MongoDB, Inc.
 * Public Domain 2008-2014 WiredTiger, Inc.
 *
 * This is free and unencumbered software released into the public domain.
 *
 * Anyone is free to copy, modify, publish, use, compile, sell, or
 * distribute this software, either in source code form or as a compiled
 * binary, for any purpose, commercial or non-commercial, and by any
 * means.
 *
 * In jurisdictions that recognize copyright laws, the author or authors
 * of this software dedicate any and all copyright interest in the
 * software to the public domain. We make this dedication for the benefit
 * of the public at large and to the detriment of our heirs and
 * successors. We intend this dedication to be an overt act of
 * relinquishment in perpetuity of all present and future rights to this
 * software under copyright law.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */
package com.wiredtiger.db;

import java.lang.String;

/**
 * An internal helper class with utilities for packing and unpacking values.
 *
 * Applications should not need to use this class.
 */
class PackUtil {
    /* Contants. */
    final static byte NEG_MULTI_MARKER = (byte)0x10;
    final static byte NEG_2BYTE_MARKER = (byte)0x20;
    final static byte NEG_1BYTE_MARKER = (byte)0x40;
    final static byte POS_1BYTE_MARKER = (byte)0x80;
    final static byte POS_2BYTE_MARKER = (byte)0xc0;
    final static byte POS_MULTI_MARKER = (byte)0xe0;

    final static int NEG_1BYTE_MIN = ((-1) << 6);
    final static int NEG_2BYTE_MIN = (((-1) << 13) + NEG_1BYTE_MIN);
    final static int POS_1BYTE_MAX = ((1 << 6) - 1);
    final static int POS_2BYTE_MAX = ((1 << 13) + POS_1BYTE_MAX);

    // See: http://docs.python.org/2/library/struct.html for an explanation
    // of what these special characters mean.
    // TODO: Care about byte ordering and padding in packed formats.
    final static String PackSpecialCharacters = "@=<>!x";

    final static int SIZEOF_LONG = 8;

    /**
     * Extract bits from a value, counting from LSB == 0.
     *
     * \param x The value to extract bits from.
     * \param start The first bit to extract.
     * \param end The last bit to extract.
     */
    public static byte GET_BITS(long x, int start, int end) {
        return (byte)((x & ((1 << start) - 1)) >> end);
    }


}
