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A Java implementation of the Amazon Ion data notation.
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/*
* Copyright 2007-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* or in the "license" file accompanying this file. This file 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 com.amazon.ion.util;
import static com.amazon.ion.impl._Private_IonConstants.BINARY_VERSION_MARKER_1_0;
import static com.amazon.ion.util.GzipOrRawInputStream.GZIP_HEADER;
import com.amazon.ion.IonException;
import com.amazon.ion.IonReader;
import com.amazon.ion.IonType;
import com.amazon.ion.IonWriter;
import com.amazon.ion.impl._Private_ListWriter;
import java.io.IOException;
import java.io.InputStream;
/**
* Utility methods for working with the Ion streaming interfaces,
* {@link IonReader} and {@link IonWriter}.
*/
public class IonStreamUtils
{
/**
* Determines whether a buffer contains Ion binary data by looking for the
* presence of the Ion Version Marker at its start.
* A {@code false} result does not imply that the buffer has Ion text,
* just that it's not Ion binary.
*
* @param buffer the data to check.
*
* @return {@code true} if the buffer contains Ion binary (starting from
* offset zero); {@code false} if the buffer is null or too short.
*
* @see #isIonBinary(byte[], int, int)
*/
public static boolean isIonBinary(byte[] buffer)
{
return buffer != null && isIonBinary(buffer, 0, buffer.length);
}
/**
* Determines whether a buffer contains Ion binary data by looking for the
* presence of the Ion Version Marker at a given offset.
* A {@code false} result does not imply that the buffer has Ion text,
* just that it's not Ion binary.
*
* @param buffer the data to check.
* @param offset the position in the buffer at which to start reading.
* @param length the number of bytes in the buffer that are valid,
* starting from {@code offset}.
*
* @return {@code true} if the buffer contains Ion binary (starting from
* {@code offset}); {@code false} if the buffer is null or if the
* {@code length} is too short.
*
* @see #isIonBinary(byte[])
*/
public static boolean isIonBinary(byte[] buffer, int offset, int length)
{
return cookieMatches(BINARY_VERSION_MARKER_1_0, buffer, offset, length);
}
/**
* Determines whether a buffer contains GZIPped data.
*
* @param buffer the data to check.
* @param offset the position in the buffer at which to start reading.
* @param length the number of bytes in the buffer that are valid,
* starting from {@code offset}.
*
* @return {@code true} if the buffer contains GZIPped data; {@code false}
* if the buffer is null or if the {@code length} is too short.
*
*/
public static boolean isGzip(byte[] buffer, int offset, int length)
{
return cookieMatches(GZIP_HEADER, buffer, offset, length);
}
private static boolean cookieMatches(byte[] cookie,
byte[] buffer,
int offset,
int length)
{
if (buffer == null || length < cookie.length)
{
return false;
}
for (int i = 0; i < cookie.length; i++)
{
if (cookie[i] != buffer[offset + i])
{
return false;
}
}
return true;
}
/**
* Returns a stream that decompresses a stream if it contains GZIPped data,
* otherwise has no effect on the stream (but may wrap it).
*
*/
public static InputStream unGzip(InputStream in)
throws IOException
{
return new GzipOrRawInputStream(in);
}
/**
* Wraps the given Exception with IonException and throws.
* @param e the exception to wrap.
*/
public static void throwAsIonException(Exception e) {
throw new IonException(e);
}
//=========================================================================
/**
* writes an IonList with a series of IonBool values. This
* starts a List, writes the values (without any annoations)
* and closes the list. For text and tree writers this is
* just a convienience, but for the binary writer it can be
* optimized internally.
* @param values boolean values to populate the list with
*/
public static void writeBoolList(IonWriter writer, boolean[] values)
throws IOException
{
if (writer instanceof _Private_ListWriter) {
((_Private_ListWriter)writer).writeBoolList(values);
return;
}
writer.stepIn(IonType.LIST);
for (int ii=0; ii