Here you can find the source of getUnsignedVarInt(ByteBuffer buffer, int numBytes)
Parameter | Description |
---|---|
buffer | Buffer containing the variable length int |
public static int getUnsignedVarInt(ByteBuffer buffer, int numBytes)
//package com.java2s; /*/*from ww w . java 2 s . co m*/ Copyright (c) 2005 Health Market Science, Inc. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA You can contact Health Market Science at info@healthmarketscience.com or at the following address: Health Market Science 2700 Horizon Drive Suite 200 King of Prussia, PA 19406 */ import java.nio.ByteBuffer; import java.nio.ByteOrder; public class Main { /** * Read an unsigned variable length int from a buffer * @param buffer Buffer containing the variable length int * @return The unsigned int */ public static int getUnsignedVarInt(ByteBuffer buffer, int numBytes) { int pos = buffer.position(); int rtn = getUnsignedVarInt(buffer, pos, numBytes); buffer.position(pos + numBytes); return rtn; } /** * Read an unsigned variable length int from a buffer * @param buffer Buffer containing the variable length int * @param offset Offset at which to read the value * @return The unsigned int */ public static int getUnsignedVarInt(ByteBuffer buffer, int offset, int numBytes) { switch (numBytes) { case 1: return getUnsignedByte(buffer, offset); case 2: return getUnsignedShort(buffer, offset); case 3: return get3ByteInt(buffer, offset); case 4: return buffer.getInt(offset); default: throw new IllegalArgumentException("Invalid num bytes " + numBytes); } } /** * Read an unsigned byte from a buffer * @param buffer Buffer containing the bytes * @return The unsigned byte as an int */ public static int getUnsignedByte(ByteBuffer buffer) { int pos = buffer.position(); int rtn = getUnsignedByte(buffer, pos); buffer.position(pos + 1); return rtn; } /** * Read an unsigned byte from a buffer * @param buffer Buffer containing the bytes * @param offset Offset at which to read the byte * @return The unsigned byte as an int */ public static int getUnsignedByte(ByteBuffer buffer, int offset) { return asUnsignedByte(buffer.get(offset)); } /** * Read an unsigned short from a buffer * @param buffer Buffer containing the short * @return The unsigned short as an int */ public static int getUnsignedShort(ByteBuffer buffer) { int pos = buffer.position(); int rtn = getUnsignedShort(buffer, pos); buffer.position(pos + 2); return rtn; } /** * Read an unsigned short from a buffer * @param buffer Buffer containing the short * @param offset Offset at which to read the short * @return The unsigned short as an int */ public static int getUnsignedShort(ByteBuffer buffer, int offset) { return asUnsignedShort(buffer.getShort(offset)); } /** * Read a 3 byte int from a buffer * @param buffer Buffer containing the bytes * @return The int */ public static int get3ByteInt(ByteBuffer buffer) { return get3ByteInt(buffer, buffer.order()); } /** * Read a 3 byte int from a buffer * @param buffer Buffer containing the bytes * @param order the order of the bytes of the int * @return The int */ public static int get3ByteInt(ByteBuffer buffer, ByteOrder order) { int pos = buffer.position(); int rtn = get3ByteInt(buffer, pos, order); buffer.position(pos + 3); return rtn; } /** * Read a 3 byte int from a buffer * @param buffer Buffer containing the bytes * @param offset Offset at which to start reading the int * @return The int */ public static int get3ByteInt(ByteBuffer buffer, int offset) { return get3ByteInt(buffer, offset, buffer.order()); } /** * Read a 3 byte int from a buffer * @param buffer Buffer containing the bytes * @param offset Offset at which to start reading the int * @param order the order of the bytes of the int * @return The int */ public static int get3ByteInt(ByteBuffer buffer, int offset, ByteOrder order) { int offInc = 1; if (order == ByteOrder.BIG_ENDIAN) { offInc = -1; offset += 2; } int rtn = getUnsignedByte(buffer, offset); rtn += (getUnsignedByte(buffer, offset + (1 * offInc)) << 8); rtn += (getUnsignedByte(buffer, offset + (2 * offInc)) << 16); return rtn; } /** * @param buffer Buffer containing the bytes * @param order the order of the bytes of the int * @return an int from the current position in the given buffer, read using * the given ByteOrder */ public static int getInt(ByteBuffer buffer, ByteOrder order) { int offset = buffer.position(); int rtn = getInt(buffer, offset, order); buffer.position(offset + 4); return rtn; } /** * @param buffer Buffer containing the bytes * @param offset Offset at which to start reading the int * @param order the order of the bytes of the int * @return an int from the given position in the given buffer, read using * the given ByteOrder */ public static int getInt(ByteBuffer buffer, int offset, ByteOrder order) { ByteOrder origOrder = buffer.order(); try { return buffer.order(order).getInt(offset); } finally { buffer.order(origOrder); } } /** * @return the byte value converted to an unsigned int value */ public static int asUnsignedByte(byte b) { return b & 0xFF; } /** * @return the short value converted to an unsigned int value */ public static int asUnsignedShort(short s) { return s & 0xFFFF; } }