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/*
* Copyright 2007 - 2018 ETH Zuerich, CISD and SIS.
*
* Licensed 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.
*/
package ch.systemsx.cisd.base.convert;
import ch.systemsx.cisd.base.convert.NativeData.ByteOrder;
/**
* An enum for encoding array of numbers (integer or float) in native (host) format.
*
* @author Bernd Rinn
*/
public enum NativeArrayEncoding
{
INT8_NATIVE(false, (byte) 1, NativeData.ByteOrder.NATIVE),
INT16_LITTLE_ENDIAN(false, (byte) 2, NativeData.ByteOrder.LITTLE_ENDIAN),
INT32_LITTLE_ENDIAN(false, (byte) 4, NativeData.ByteOrder.LITTLE_ENDIAN),
INT64_LITTLE_ENDIAN(false, (byte) 8, NativeData.ByteOrder.LITTLE_ENDIAN),
INT16_BIG_ENDIAN(false, (byte) 2, NativeData.ByteOrder.BIG_ENDIAN),
INT32_BIG_ENDIAN(false, (byte) 4, NativeData.ByteOrder.BIG_ENDIAN),
INT64_BIG_ENDIAN(false, (byte) 8, NativeData.ByteOrder.BIG_ENDIAN),
FLOAT32_LITTLE_ENDIAN(true, (byte) 4, NativeData.ByteOrder.LITTLE_ENDIAN),
FLOAT64_LITTLE_ENDIAN(true, (byte) 8, NativeData.ByteOrder.LITTLE_ENDIAN),
FLOAT32_BIG_ENDIAN(true, (byte) 4, NativeData.ByteOrder.BIG_ENDIAN),
FLOAT64_BIG_ENDIAN(true, (byte) 8, NativeData.ByteOrder.BIG_ENDIAN),
;
private static final int MIN_ENCODING_HEADER_SIZE = 8;
private static final int CHAR_N = 78;
private static final int CHAR_B = 66;
private static final int CHAR_L = 76;
private static final int CHAR_I = 73;
private static final int CHAR_F = 70;
private boolean floatingPoint;
private ByteOrder byteOrder;
private byte sizeInBytes;
private byte[] magic;
NativeArrayEncoding(boolean floatingPoint, byte sizeInBytes, NativeData.ByteOrder byteOrder)
{
this.floatingPoint = floatingPoint;
this.byteOrder = byteOrder;
this.sizeInBytes = sizeInBytes;
this.magic =
new byte[]
{
(byte) (floatingPoint ? CHAR_F : CHAR_I),
(byte) ((byteOrder == ByteOrder.LITTLE_ENDIAN) ? CHAR_L
: (byteOrder == ByteOrder.BIG_ENDIAN) ? CHAR_B : CHAR_N),
sizeInBytes };
}
/**
* Returns <code>true</code>, if the encoded array is a float array.
*/
public boolean isFloatingPoint()
{
return floatingPoint;
}
/**
* Returns <code>true</code>, if the encoded array is an int array.
*/
public boolean isInteger()
{
return floatingPoint == false;
}
/**
* Returns the byte order of the array.
*/
public NativeData.ByteOrder getByteOrder()
{
return byteOrder;
}
/**
* Returns the size of one element in bytes.
*/
public byte getSizeInBytes()
{
return sizeInBytes;
}
byte[] getMagic()
{
return magic;
}
static NativeArrayEncoding tryGetIntEncoding(ByteOrder byteOrder, byte sizeInBytes)
{
assert byteOrder != null;
if (sizeInBytes == 1 && byteOrder == ByteOrder.NATIVE)
{
return INT8_NATIVE;
} else if (sizeInBytes == 2)
{
return (byteOrder == ByteOrder.LITTLE_ENDIAN) ? INT16_LITTLE_ENDIAN : INT16_BIG_ENDIAN;
} else if (sizeInBytes == 4)
{
return (byteOrder == ByteOrder.LITTLE_ENDIAN) ? INT32_LITTLE_ENDIAN : INT32_BIG_ENDIAN;
} else if (sizeInBytes == 8)
{
return (byteOrder == ByteOrder.LITTLE_ENDIAN) ? INT64_LITTLE_ENDIAN : INT64_BIG_ENDIAN;
}
return null;
}
static NativeArrayEncoding tryGetFloatEncoding(ByteOrder byteOrder, byte sizeInBytes)
{
assert byteOrder != null;
if (sizeInBytes == 4)
{
return (byteOrder == ByteOrder.LITTLE_ENDIAN) ? FLOAT32_LITTLE_ENDIAN
: FLOAT32_BIG_ENDIAN;
} else if (sizeInBytes == 8)
{
return (byteOrder == ByteOrder.LITTLE_ENDIAN) ? FLOAT64_LITTLE_ENDIAN
: FLOAT64_BIG_ENDIAN;
}
return null;
}
/**
* Returns the encoding for the given <var>byteArr</var>, or <code>null</code>, if
* <var>byteArr</var> is not an encoded array.
*/
public static NativeArrayEncoding tryGetEncoding(byte[] byteArr)
{
if (byteArr.length < MIN_ENCODING_HEADER_SIZE)
{
return null;
}
final ByteOrder byteOrder =
(byteArr[1] == CHAR_L) ? ByteOrder.LITTLE_ENDIAN
: (byteArr[1] == CHAR_B) ? ByteOrder.BIG_ENDIAN : null;
if (byteOrder == null)
{
return null;
}
if (byteArr[0] == CHAR_F)
{
return tryGetFloatEncoding(byteOrder, byteArr[2]);
} else if (byteArr[0] == CHAR_I)
{
return tryGetIntEncoding(byteOrder, byteArr[2]);
}
return null;
}
}
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