| /* ==================================================================== |
| 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. |
| ==================================================================== */ |
| |
| package org.apache.poi.sl.image; |
| |
| |
| import java.io.ByteArrayInputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| import org.apache.poi.poifs.filesystem.FileMagic; |
| import org.apache.poi.util.IOUtils; |
| import org.apache.poi.util.RecordFormatException; |
| |
| public final class ImageHeaderPNG { |
| |
| private static final int MAGIC_OFFSET = 16; |
| |
| private byte[] data; |
| |
| /** |
| * @param data The raw image data |
| */ |
| public ImageHeaderPNG(byte[] data) { |
| this.data = data; |
| } |
| |
| /** |
| * PNG created on MAC may have a 16-byte prefix which prevents successful reading. |
| * @return the trimmed PNG data |
| */ |
| public byte[] extractPNG() { |
| // |
| //Just cut it off!. |
| try (InputStream is = new ByteArrayInputStream(data)) { |
| if (is.skip(MAGIC_OFFSET) == MAGIC_OFFSET && FileMagic.valueOf(is) == FileMagic.PNG) { |
| return IOUtils.toByteArray(is); |
| } |
| } catch (IOException e) { |
| throw new RecordFormatException("Unable to parse PNG header", e); |
| } |
| |
| return data; |
| } |
| } |