mirror of
https://github.com/curioustorvald/Terrarum.git
synced 2026-03-10 13:51:53 +09:00
059abff814
Former-commit-id: 1647fa32ef6894bd7db44f741f07c2f4dcdf9054 Former-commit-id: 0e5810dcfbe1fd59b13e7cabe9f1e93c5542da2d
763 lines
26 KiB
Java
763 lines
26 KiB
Java
/*
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* Copyright (c) 2008-2010, Matthias Mann
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Matthias Mann nor the names of its contributors may
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* be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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package org.newdawn.slick.opengl;
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import java.io.EOFException;
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import java.io.IOException;
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import java.io.InputStream;
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import java.nio.ByteBuffer;
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import java.util.Arrays;
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import java.util.zip.CRC32;
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import java.util.zip.DataFormatException;
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import java.util.zip.Inflater;
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/**
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* A PNGDecoder. The slick PNG decoder is based on this class :)
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*
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* @author Matthias Mann
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*/
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public class PNGDecoder {
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public static Format ALPHA = new Format(1, true);
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public static Format LUMINANCE = new Format(1, false);
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public static Format LUMINANCE_ALPHA = new Format(2, true);
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public static Format RGB = new Format(3, false);
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public static Format RGBA = new Format(4, true);
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public static Format BGRA = new Format(4, true);
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public static Format ABGR = new Format(4, true);
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public static class Format {
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final int numComponents;
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final boolean hasAlpha;
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private Format(int numComponents, boolean hasAlpha) {
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this.numComponents = numComponents;
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this.hasAlpha = hasAlpha;
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}
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public int getNumComponents() {
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return numComponents;
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}
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public boolean isHasAlpha() {
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return hasAlpha;
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}
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}
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private static final byte[] SIGNATURE = {(byte)137, 80, 78, 71, 13, 10, 26, 10};
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private static final int IHDR = 0x49484452;
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private static final int PLTE = 0x504C5445;
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private static final int tRNS = 0x74524E53;
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private static final int IDAT = 0x49444154;
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private static final int IEND = 0x49454E44;
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private static final byte COLOR_GREYSCALE = 0;
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private static final byte COLOR_TRUECOLOR = 2;
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private static final byte COLOR_INDEXED = 3;
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private static final byte COLOR_GREYALPHA = 4;
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private static final byte COLOR_TRUEALPHA = 6;
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private final InputStream input;
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private final CRC32 crc;
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private final byte[] buffer;
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private int chunkLength;
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private int chunkType;
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private int chunkRemaining;
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private int width;
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private int height;
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private int bitdepth;
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private int colorType;
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private int bytesPerPixel;
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private byte[] palette;
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private byte[] paletteA;
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private byte[] transPixel;
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public PNGDecoder(InputStream input) throws IOException {
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this.input = input;
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this.crc = new CRC32();
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this.buffer = new byte[4096];
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readFully(buffer, 0, SIGNATURE.length);
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if(!checkSignature(buffer)) {
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throw new IOException("Not a valid PNG file");
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}
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openChunk(IHDR);
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readIHDR();
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closeChunk();
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searchIDAT: for(;;) {
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openChunk();
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switch (chunkType) {
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case IDAT:
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break searchIDAT;
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case PLTE:
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readPLTE();
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break;
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case tRNS:
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readtRNS();
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break;
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}
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closeChunk();
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}
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if(colorType == COLOR_INDEXED && palette == null) {
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throw new IOException("Missing PLTE chunk");
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}
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}
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public int getHeight() {
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return height;
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}
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public int getWidth() {
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return width;
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}
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public boolean hasAlpha() {
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return colorType == COLOR_TRUEALPHA ||
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paletteA != null || transPixel != null;
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}
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public boolean isRGB() {
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return colorType == COLOR_TRUEALPHA ||
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colorType == COLOR_TRUECOLOR ||
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colorType == COLOR_INDEXED;
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}
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/**
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* Computes the implemented format conversion for the desired format.
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*
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* @param fmt the desired format
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* @return format which best matches the desired format
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* @throws UnsupportedOperationException if this PNG file can't be decoded
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*/
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public Format decideTextureFormat(Format fmt) {
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switch (colorType) {
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case COLOR_TRUECOLOR:
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if ((fmt == ABGR) || (fmt == RGBA) || (fmt == BGRA) || (fmt == RGB)) {
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return fmt;
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}
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return RGB;
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case COLOR_TRUEALPHA:
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if ((fmt == ABGR) || (fmt == RGBA) || (fmt == BGRA) || (fmt == RGB)) {
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return fmt;
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}
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return RGBA;
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case COLOR_GREYSCALE:
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if ((fmt == LUMINANCE) || (fmt == ALPHA)) {
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return fmt;
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}
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return LUMINANCE;
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case COLOR_GREYALPHA:
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return LUMINANCE_ALPHA;
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case COLOR_INDEXED:
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if ((fmt == ABGR) || (fmt == RGBA) || (fmt == BGRA)) {
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return fmt;
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}
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return RGBA;
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default:
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throw new UnsupportedOperationException("Not yet implemented");
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}
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}
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public void decode(ByteBuffer buffer, int stride, Format fmt) throws IOException {
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final int offset = buffer.position();
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final int lineSize = ((width * bitdepth + 7) / 8) * bytesPerPixel;
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byte[] curLine = new byte[lineSize+1];
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byte[] prevLine = new byte[lineSize+1];
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byte[] palLine = (bitdepth < 8) ? new byte[width+1] : null;
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final Inflater inflater = new Inflater();
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try {
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for(int y=0 ; y<height ; y++) {
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readChunkUnzip(inflater, curLine, 0, curLine.length);
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unfilter(curLine, prevLine);
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buffer.position(offset + y*stride);
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switch (colorType) {
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case COLOR_TRUECOLOR:
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if (fmt == ABGR) {
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copyRGBtoABGR(buffer, curLine);
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}
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else if (fmt == RGBA) {
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copyRGBtoRGBA(buffer, curLine);
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}
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else if (fmt == BGRA) {
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copyRGBtoBGRA(buffer, curLine);
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}
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else if (fmt == RGB) {
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copy(buffer, curLine);
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} else {
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throw new UnsupportedOperationException("Unsupported format for this image");
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}
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break;
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case COLOR_TRUEALPHA:
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if (fmt == ABGR) {
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copyRGBAtoABGR(buffer, curLine);
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} else if (fmt == RGBA) {
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copy(buffer, curLine);
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} else if (fmt == BGRA) {
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copyRGBAtoBGRA(buffer, curLine); break;
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} else if (fmt == RGB) {
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copyRGBAtoRGB(buffer, curLine); break;
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} else {
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throw new UnsupportedOperationException("Unsupported format for this image");
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}
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break;
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case COLOR_GREYSCALE:
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if ((fmt == LUMINANCE) || (fmt == ALPHA)) {
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copy(buffer, curLine);
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} else {
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throw new UnsupportedOperationException("Unsupported format for this image");
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}
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break;
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case COLOR_GREYALPHA:
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if (fmt == LUMINANCE_ALPHA) {
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copy(buffer, curLine);
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} else {
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throw new UnsupportedOperationException("Unsupported format for this image");
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}
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break;
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case COLOR_INDEXED:
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switch(bitdepth) {
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case 8: palLine = curLine; break;
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case 4: expand4(curLine, palLine); break;
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case 2: expand2(curLine, palLine); break;
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case 1: expand1(curLine, palLine); break;
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default: throw new UnsupportedOperationException("Unsupported bitdepth for this image");
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}
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if (fmt == ABGR) {
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copyPALtoABGR(buffer, palLine);
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} else if (fmt == RGBA) {
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copyPALtoRGBA(buffer, palLine);
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} else if (fmt == BGRA) {
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copyPALtoBGRA(buffer, palLine);
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} else {
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throw new UnsupportedOperationException("Unsupported format for this image");
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}
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break;
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default:
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throw new UnsupportedOperationException("Not yet implemented");
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}
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byte[] tmp = curLine;
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curLine = prevLine;
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prevLine = tmp;
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}
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} finally {
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inflater.end();
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}
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}
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private void copy(ByteBuffer buffer, byte[] curLine) {
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buffer.put(curLine, 1, curLine.length-1);
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}
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private void copyRGBtoABGR(ByteBuffer buffer, byte[] curLine) {
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if(transPixel != null) {
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byte tr = transPixel[1];
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byte tg = transPixel[3];
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byte tb = transPixel[5];
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for(int i=1,n=curLine.length ; i<n ; i+=3) {
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byte r = curLine[i];
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byte g = curLine[i+1];
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byte b = curLine[i+2];
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byte a = (byte)0xFF;
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if(r==tr && g==tg && b==tb) {
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a = 0;
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}
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buffer.put(a).put(b).put(g).put(r);
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}
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} else {
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for(int i=1,n=curLine.length ; i<n ; i+=3) {
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buffer.put((byte)0xFF).put(curLine[i+2]).put(curLine[i+1]).put(curLine[i]);
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}
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}
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}
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private void copyRGBtoRGBA(ByteBuffer buffer, byte[] curLine) {
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if(transPixel != null) {
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byte tr = transPixel[1];
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byte tg = transPixel[3];
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byte tb = transPixel[5];
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for(int i=1,n=curLine.length ; i<n ; i+=3) {
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byte r = curLine[i];
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byte g = curLine[i+1];
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byte b = curLine[i+2];
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byte a = (byte)0xFF;
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if(r==tr && g==tg && b==tb) {
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a = 0;
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}
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buffer.put(r).put(g).put(b).put(a);
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}
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} else {
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for(int i=1,n=curLine.length ; i<n ; i+=3) {
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buffer.put(curLine[i]).put(curLine[i+1]).put(curLine[i+2]).put((byte)0xFF);
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}
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}
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}
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private void copyRGBtoBGRA(ByteBuffer buffer, byte[] curLine) {
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if(transPixel != null) {
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byte tr = transPixel[1];
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byte tg = transPixel[3];
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byte tb = transPixel[5];
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for(int i=1,n=curLine.length ; i<n ; i+=3) {
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byte r = curLine[i];
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byte g = curLine[i+1];
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byte b = curLine[i+2];
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byte a = (byte)0xFF;
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if(r==tr && g==tg && b==tb) {
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a = 0;
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}
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buffer.put(b).put(g).put(r).put(a);
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}
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} else {
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for(int i=1,n=curLine.length ; i<n ; i+=3) {
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buffer.put(curLine[i+2]).put(curLine[i+1]).put(curLine[i]).put((byte)0xFF);
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}
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}
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}
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private void copyRGBAtoABGR(ByteBuffer buffer, byte[] curLine) {
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for(int i=1,n=curLine.length ; i<n ; i+=4) {
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buffer.put(curLine[i+3]).put(curLine[i+2]).put(curLine[i+1]).put(curLine[i]);
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}
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}
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private void copyRGBAtoBGRA(ByteBuffer buffer, byte[] curLine) {
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for(int i=1,n=curLine.length ; i<n ; i+=4) {
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buffer.put(curLine[i+2]).put(curLine[i+1]).put(curLine[i+0]).put(curLine[i+3]);
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}
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}
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private void copyRGBAtoRGB(ByteBuffer buffer, byte[] curLine) {
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for(int i=1,n=curLine.length ; i<n ; i+=4) {
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buffer.put(curLine[i]).put(curLine[i+1]).put(curLine[i+2]);
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}
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}
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private void copyPALtoABGR(ByteBuffer buffer, byte[] curLine) {
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if(paletteA != null) {
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for(int i=1,n=curLine.length ; i<n ; i+=1) {
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int idx = curLine[i] & 255;
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byte r = palette[idx*3 + 0];
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byte g = palette[idx*3 + 1];
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byte b = palette[idx*3 + 2];
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byte a = paletteA[idx];
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buffer.put(a).put(b).put(g).put(r);
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}
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} else {
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for(int i=1,n=curLine.length ; i<n ; i+=1) {
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int idx = curLine[i] & 255;
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byte r = palette[idx*3 + 0];
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byte g = palette[idx*3 + 1];
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byte b = palette[idx*3 + 2];
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byte a = (byte)0xFF;
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buffer.put(a).put(b).put(g).put(r);
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}
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}
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}
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private void copyPALtoRGBA(ByteBuffer buffer, byte[] curLine) {
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if(paletteA != null) {
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for(int i=1,n=curLine.length ; i<n ; i+=1) {
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int idx = curLine[i] & 255;
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byte r = palette[idx*3 + 0];
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byte g = palette[idx*3 + 1];
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byte b = palette[idx*3 + 2];
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byte a = paletteA[idx];
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buffer.put(r).put(g).put(b).put(a);
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}
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} else {
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for(int i=1,n=curLine.length ; i<n ; i+=1) {
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int idx = curLine[i] & 255;
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byte r = palette[idx*3 + 0];
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byte g = palette[idx*3 + 1];
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byte b = palette[idx*3 + 2];
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byte a = (byte)0xFF;
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buffer.put(r).put(g).put(b).put(a);
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}
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}
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}
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private void copyPALtoBGRA(ByteBuffer buffer, byte[] curLine) {
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if(paletteA != null) {
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for(int i=1,n=curLine.length ; i<n ; i+=1) {
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int idx = curLine[i] & 255;
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byte r = palette[idx*3 + 0];
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byte g = palette[idx*3 + 1];
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byte b = palette[idx*3 + 2];
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byte a = paletteA[idx];
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buffer.put(b).put(g).put(r).put(a);
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}
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} else {
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for(int i=1,n=curLine.length ; i<n ; i+=1) {
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int idx = curLine[i] & 255;
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byte r = palette[idx*3 + 0];
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byte g = palette[idx*3 + 1];
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byte b = palette[idx*3 + 2];
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byte a = (byte)0xFF;
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buffer.put(b).put(g).put(r).put(a);
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}
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}
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}
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private void expand4(byte[] src, byte[] dst) {
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for(int i=1,n=dst.length ; i<n ; i+=2) {
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int val = src[1 + (i >> 1)] & 255;
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switch(n-i) {
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default: dst[i+1] = (byte)(val & 15);
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case 1: dst[i ] = (byte)(val >> 4);
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}
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}
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}
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private void expand2(byte[] src, byte[] dst) {
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for(int i=1,n=dst.length ; i<n ; i+=4) {
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int val = src[1 + (i >> 2)] & 255;
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switch(n-i) {
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default: dst[i+3] = (byte)((val ) & 3);
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case 3: dst[i+2] = (byte)((val >> 2) & 3);
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case 2: dst[i+1] = (byte)((val >> 4) & 3);
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case 1: dst[i ] = (byte)((val >> 6) );
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}
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}
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}
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private void expand1(byte[] src, byte[] dst) {
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for(int i=1,n=dst.length ; i<n ; i+=8) {
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int val = src[1 + (i >> 3)] & 255;
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switch(n-i) {
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default: dst[i+7] = (byte)((val ) & 1);
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case 7: dst[i+6] = (byte)((val >> 1) & 1);
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case 6: dst[i+5] = (byte)((val >> 2) & 1);
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case 5: dst[i+4] = (byte)((val >> 3) & 1);
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case 4: dst[i+3] = (byte)((val >> 4) & 1);
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case 3: dst[i+2] = (byte)((val >> 5) & 1);
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case 2: dst[i+1] = (byte)((val >> 6) & 1);
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case 1: dst[i ] = (byte)((val >> 7) );
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}
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}
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}
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private void unfilter(byte[] curLine, byte[] prevLine) throws IOException {
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switch (curLine[0]) {
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case 0: // none
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break;
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case 1:
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unfilterSub(curLine);
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break;
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case 2:
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unfilterUp(curLine, prevLine);
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break;
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case 3:
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unfilterAverage(curLine, prevLine);
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break;
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case 4:
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unfilterPaeth(curLine, prevLine);
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break;
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default:
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throw new IOException("invalide filter type in scanline: " + curLine[0]);
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|
}
|
|
}
|
|
|
|
private void unfilterSub(byte[] curLine) {
|
|
final int bpp = this.bytesPerPixel;
|
|
for(int i=bpp+1,n=curLine.length ; i<n ; ++i) {
|
|
curLine[i] += curLine[i-bpp];
|
|
}
|
|
}
|
|
|
|
private void unfilterUp(byte[] curLine, byte[] prevLine) {
|
|
final int bpp = this.bytesPerPixel;
|
|
for(int i=1,n=curLine.length ; i<n ; ++i) {
|
|
curLine[i] += prevLine[i];
|
|
}
|
|
}
|
|
|
|
private void unfilterAverage(byte[] curLine, byte[] prevLine) {
|
|
final int bpp = this.bytesPerPixel;
|
|
|
|
int i;
|
|
for(i=1 ; i<=bpp ; ++i) {
|
|
curLine[i] += (byte)((prevLine[i] & 0xFF) >>> 1);
|
|
}
|
|
for(int n=curLine.length ; i<n ; ++i) {
|
|
curLine[i] += (byte)(((prevLine[i] & 0xFF) + (curLine[i - bpp] & 0xFF)) >>> 1);
|
|
}
|
|
}
|
|
|
|
private void unfilterPaeth(byte[] curLine, byte[] prevLine) {
|
|
final int bpp = this.bytesPerPixel;
|
|
|
|
int i;
|
|
for(i=1 ; i<=bpp ; ++i) {
|
|
curLine[i] += prevLine[i];
|
|
}
|
|
for(int n=curLine.length ; i<n ; ++i) {
|
|
int a = curLine[i - bpp] & 255;
|
|
int b = prevLine[i] & 255;
|
|
int c = prevLine[i - bpp] & 255;
|
|
int p = a + b - c;
|
|
int pa = p - a; if(pa < 0) pa = -pa;
|
|
int pb = p - b; if(pb < 0) pb = -pb;
|
|
int pc = p - c; if(pc < 0) pc = -pc;
|
|
if(pa<=pb && pa<=pc)
|
|
c = a;
|
|
else if(pb<=pc)
|
|
c = b;
|
|
curLine[i] += (byte)c;
|
|
}
|
|
}
|
|
|
|
private void readIHDR() throws IOException {
|
|
checkChunkLength(13);
|
|
readChunk(buffer, 0, 13);
|
|
width = readInt(buffer, 0);
|
|
height = readInt(buffer, 4);
|
|
bitdepth = buffer[8] & 255;
|
|
colorType = buffer[9] & 255;
|
|
|
|
switch (colorType) {
|
|
case COLOR_GREYSCALE:
|
|
if(bitdepth != 8) {
|
|
throw new IOException("Unsupported bit depth: " + bitdepth);
|
|
}
|
|
bytesPerPixel = 1;
|
|
break;
|
|
case COLOR_GREYALPHA:
|
|
if(bitdepth != 8) {
|
|
throw new IOException("Unsupported bit depth: " + bitdepth);
|
|
}
|
|
bytesPerPixel = 2;
|
|
break;
|
|
case COLOR_TRUECOLOR:
|
|
if(bitdepth != 8) {
|
|
throw new IOException("Unsupported bit depth: " + bitdepth);
|
|
}
|
|
bytesPerPixel = 3;
|
|
break;
|
|
case COLOR_TRUEALPHA:
|
|
if(bitdepth != 8) {
|
|
throw new IOException("Unsupported bit depth: " + bitdepth);
|
|
}
|
|
bytesPerPixel = 4;
|
|
break;
|
|
case COLOR_INDEXED:
|
|
switch(bitdepth) {
|
|
case 8:
|
|
case 4:
|
|
case 2:
|
|
case 1:
|
|
bytesPerPixel = 1;
|
|
break;
|
|
default:
|
|
throw new IOException("Unsupported bit depth: " + bitdepth);
|
|
}
|
|
break;
|
|
default:
|
|
throw new IOException("unsupported color format: " + colorType);
|
|
}
|
|
|
|
if(buffer[10] != 0) {
|
|
throw new IOException("unsupported compression method");
|
|
}
|
|
if(buffer[11] != 0) {
|
|
throw new IOException("unsupported filtering method");
|
|
}
|
|
if(buffer[12] != 0) {
|
|
throw new IOException("unsupported interlace method");
|
|
}
|
|
}
|
|
|
|
private void readPLTE() throws IOException {
|
|
int paletteEntries = chunkLength / 3;
|
|
if(paletteEntries < 1 || paletteEntries > 256 || (chunkLength % 3) != 0) {
|
|
throw new IOException("PLTE chunk has wrong length");
|
|
}
|
|
palette = new byte[paletteEntries*3];
|
|
readChunk(palette, 0, palette.length);
|
|
}
|
|
|
|
private void readtRNS() throws IOException {
|
|
switch (colorType) {
|
|
case COLOR_GREYSCALE:
|
|
checkChunkLength(2);
|
|
transPixel = new byte[2];
|
|
readChunk(transPixel, 0, 2);
|
|
break;
|
|
case COLOR_TRUECOLOR:
|
|
checkChunkLength(6);
|
|
transPixel = new byte[6];
|
|
readChunk(transPixel, 0, 6);
|
|
break;
|
|
case COLOR_INDEXED:
|
|
if(palette == null) {
|
|
throw new IOException("tRNS chunk without PLTE chunk");
|
|
}
|
|
paletteA = new byte[palette.length/3];
|
|
Arrays.fill(paletteA, (byte)0xFF);
|
|
readChunk(paletteA, 0, paletteA.length);
|
|
break;
|
|
default:
|
|
// just ignore it
|
|
}
|
|
}
|
|
|
|
private void closeChunk() throws IOException {
|
|
if(chunkRemaining > 0) {
|
|
// just skip the rest and the CRC
|
|
skip(chunkRemaining + 4);
|
|
} else {
|
|
readFully(buffer, 0, 4);
|
|
int expectedCrc = readInt(buffer, 0);
|
|
int computedCrc = (int)crc.getValue();
|
|
if(computedCrc != expectedCrc) {
|
|
throw new IOException("Invalid CRC");
|
|
}
|
|
}
|
|
chunkRemaining = 0;
|
|
chunkLength = 0;
|
|
chunkType = 0;
|
|
}
|
|
|
|
private void openChunk() throws IOException {
|
|
readFully(buffer, 0, 8);
|
|
chunkLength = readInt(buffer, 0);
|
|
chunkType = readInt(buffer, 4);
|
|
chunkRemaining = chunkLength;
|
|
crc.reset();
|
|
crc.update(buffer, 4, 4); // only chunkType
|
|
}
|
|
|
|
private void openChunk(int expected) throws IOException {
|
|
openChunk();
|
|
if(chunkType != expected) {
|
|
throw new IOException("Expected chunk: " + Integer.toHexString(expected));
|
|
}
|
|
}
|
|
|
|
private void checkChunkLength(int expected) throws IOException {
|
|
if(chunkLength != expected) {
|
|
throw new IOException("Chunk has wrong size");
|
|
}
|
|
}
|
|
|
|
private int readChunk(byte[] buffer, int offset, int length) throws IOException {
|
|
if(length > chunkRemaining) {
|
|
length = chunkRemaining;
|
|
}
|
|
readFully(buffer, offset, length);
|
|
crc.update(buffer, offset, length);
|
|
chunkRemaining -= length;
|
|
return length;
|
|
}
|
|
|
|
private void refillInflater(Inflater inflater) throws IOException {
|
|
while(chunkRemaining == 0) {
|
|
closeChunk();
|
|
openChunk(IDAT);
|
|
}
|
|
int read = readChunk(buffer, 0, buffer.length);
|
|
inflater.setInput(buffer, 0, read);
|
|
}
|
|
|
|
private void readChunkUnzip(Inflater inflater, byte[] buffer, int offset, int length) throws IOException {
|
|
try {
|
|
do {
|
|
int read = inflater.inflate(buffer, offset, length);
|
|
if(read <= 0) {
|
|
if(inflater.finished()) {
|
|
throw new EOFException();
|
|
}
|
|
if(inflater.needsInput()) {
|
|
refillInflater(inflater);
|
|
} else {
|
|
throw new IOException("Can't inflate " + length + " bytes");
|
|
}
|
|
} else {
|
|
offset += read;
|
|
length -= read;
|
|
}
|
|
} while(length > 0);
|
|
} catch (DataFormatException ex) {
|
|
throw (IOException)(new IOException("inflate error").initCause(ex));
|
|
}
|
|
}
|
|
|
|
private void readFully(byte[] buffer, int offset, int length) throws IOException {
|
|
do {
|
|
int read = input.read(buffer, offset, length);
|
|
if(read < 0) {
|
|
throw new EOFException();
|
|
}
|
|
offset += read;
|
|
length -= read;
|
|
} while(length > 0);
|
|
}
|
|
|
|
private int readInt(byte[] buffer, int offset) {
|
|
return
|
|
((buffer[offset ] ) << 24) |
|
|
((buffer[offset+1] & 255) << 16) |
|
|
((buffer[offset+2] & 255) << 8) |
|
|
((buffer[offset+3] & 255) );
|
|
}
|
|
|
|
private void skip(long amount) throws IOException {
|
|
while(amount > 0) {
|
|
long skipped = input.skip(amount);
|
|
if(skipped < 0) {
|
|
throw new EOFException();
|
|
}
|
|
amount -= skipped;
|
|
}
|
|
}
|
|
|
|
private static boolean checkSignature(byte[] buffer) {
|
|
for(int i=0 ; i<SIGNATURE.length ; i++) {
|
|
if(buffer[i] != SIGNATURE[i]) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
}
|