| package org.apache.directmemory.memory.buffer; |
| |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| public final class Int32Compressor |
| { |
| |
| private Int32Compressor() |
| { |
| } |
| |
| static final byte INT32_FULL = 1; |
| |
| static final byte INT32_COMPRESSED_SINGLE = 2; |
| |
| static final byte INT32_COMPRESSED_DOUBLE = 3; |
| |
| static final byte INT32_COMPRESSED_TRIPPLE = 4; |
| |
| static final int INT32_MAX_SINGLE = 0x7F; |
| |
| static final int INT32_MIN_SINGLE = ~INT32_MAX_SINGLE + 1; |
| |
| static final int INT32_MAX_DOUBLE = 0x7FFF; |
| |
| static final int INT32_MIN_DOUBLE = ~INT32_MAX_DOUBLE + 1; |
| |
| static final int INT32_MAX_TRIPPLE = 0x7FFFFF; |
| |
| static final int INT32_MIN_TRIPPLE = ~INT32_MAX_TRIPPLE + 1; |
| |
| public static void writeInt32( int value, WritableMemoryBuffer memoryBuffer ) |
| { |
| if ( value >= INT32_MIN_SINGLE && value <= INT32_MAX_SINGLE ) |
| { |
| value = value < 0 ? ( ~value + 1 ) | ( 1 << 7 ) : value; |
| memoryBuffer.writeByte( INT32_COMPRESSED_SINGLE ); |
| memoryBuffer.writeByte( (byte) value ); |
| } |
| else if ( value >= INT32_MIN_DOUBLE && value <= INT32_MAX_DOUBLE ) |
| { |
| value = value < 0 ? ( ~value + 1 ) | ( 1 << 15 ) : value; |
| memoryBuffer.writeByte( INT32_COMPRESSED_DOUBLE ); |
| memoryBuffer.writeByte( (byte) ( value >> 8 ) ); |
| memoryBuffer.writeByte( (byte) value ); |
| } |
| else if ( value >= INT32_MIN_TRIPPLE && value <= INT32_MAX_TRIPPLE ) |
| { |
| value = value < 0 ? ( ~value + 1 ) | ( 1 << 23 ) : value; |
| memoryBuffer.writeByte( INT32_COMPRESSED_TRIPPLE ); |
| memoryBuffer.writeByte( (byte) ( value >> 16 ) ); |
| memoryBuffer.writeByte( (byte) ( value >> 8 ) ); |
| memoryBuffer.writeByte( (byte) value ); |
| } |
| else |
| { |
| memoryBuffer.writeByte( INT32_FULL ); |
| memoryBuffer.writeByte( (byte) ( value >> 24 ) ); |
| memoryBuffer.writeByte( (byte) ( value >> 16 ) ); |
| memoryBuffer.writeByte( (byte) ( value >> 8 ) ); |
| memoryBuffer.writeByte( (byte) value ); |
| } |
| } |
| |
| public static int readInt32( ReadableMemoryBuffer memoryBuffer ) |
| { |
| byte type = memoryBuffer.readByte(); |
| switch ( type ) |
| { |
| case INT32_COMPRESSED_SINGLE: |
| { |
| int data = memoryBuffer.readByte() & 0xFF; |
| return ( ( data >> 7 ) & 1 ) == 1 ? ~( data ^ ( 1 << 7 ) ) + 1 : data; |
| } |
| |
| case INT32_COMPRESSED_DOUBLE: |
| { |
| int data = ( ( memoryBuffer.readByte() & 0xFF ) << 8 ) | ( memoryBuffer.readByte() & 0xFF ); |
| return ( ( data >> 15 ) & 1 ) == 1 ? ~( data ^ ( 1 << 15 ) ) + 1 : data; |
| } |
| |
| case INT32_COMPRESSED_TRIPPLE: |
| { |
| int data = |
| ( ( memoryBuffer.readByte() & 0xFF ) << 16 ) | ( ( memoryBuffer.readByte() & 0xFF ) << 8 ) |
| | ( memoryBuffer.readByte() & 0xFF ); |
| return ( ( data >> 23 ) & 1 ) == 1 ? ~( data ^ ( 1 << 23 ) ) + 1 : data; |
| } |
| } |
| |
| return ( ( memoryBuffer.readByte() & 0xFF ) << 24 ) | ( ( memoryBuffer.readByte() & 0xFF ) << 16 ) |
| | ( ( memoryBuffer.readByte() & 0xFF ) << 8 ) | ( memoryBuffer.readByte() & 0xFF ); |
| } |
| |
| } |