70 lines
2.6 KiB
Java
70 lines
2.6 KiB
Java
/*-
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* Public Domain 2008-2014 WiredTiger, Inc.
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*
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* This is free and unencumbered software released into the public domain.
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*
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* Anyone is free to copy, modify, publish, use, compile, sell, or
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* distribute this software, either in source code form or as a compiled
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* binary, for any purpose, commercial or non-commercial, and by any
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* means.
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*
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* In jurisdictions that recognize copyright laws, the author or authors
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* of this software dedicate any and all copyright interest in the
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* software to the public domain. We make this dedication for the benefit
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* of the public at large and to the detriment of our heirs and
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* successors. We intend this dedication to be an overt act of
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* relinquishment in perpetuity of all present and future rights to this
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* software under copyright law.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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package com.wiredtiger.db;
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import java.lang.String;
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/**
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* An internal helper class with utilities for packing and unpacking values.
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*
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* Applications should not need to use this class.
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*/
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class PackUtil {
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/* Contants. */
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final static byte NEG_MULTI_MARKER = (byte)0x10;
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final static byte NEG_2BYTE_MARKER = (byte)0x20;
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final static byte NEG_1BYTE_MARKER = (byte)0x40;
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final static byte POS_1BYTE_MARKER = (byte)0x80;
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final static byte POS_2BYTE_MARKER = (byte)0xc0;
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final static byte POS_MULTI_MARKER = (byte)0xe0;
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final static int NEG_1BYTE_MIN = ((-1) << 6);
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final static int NEG_2BYTE_MIN = (((-1) << 13) + NEG_1BYTE_MIN);
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final static int POS_1BYTE_MAX = ((1 << 6) - 1);
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final static int POS_2BYTE_MAX = ((1 << 13) + POS_1BYTE_MAX);
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// See: http://docs.python.org/2/library/struct.html for an explanation
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// of what these special characters mean.
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// TODO: Care about byte ordering and padding in packed formats.
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final static String PackSpecialCharacters = "@=<>!x";
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final static int SIZEOF_LONG = 8;
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/**
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* Extract bits from a value, counting from LSB == 0.
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*
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* \param x The value to extract bits from.
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* \param start The first bit to extract.
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* \param end The last bit to extract.
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*/
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public static byte GET_BITS(long x, int start, int end) {
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return (byte)((x & ((1 << start) - 1)) >> end);
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}
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}
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