Author: kurmiashish
Date: 2009-04-18 19:33:36 +0000 (Sat, 18 Apr 2009)
New Revision: 27016
Added:
trunk/freenet/src/freenet/clients/http/filter/BMPFilter.java
Log:
Added: trunk/freenet/src/freenet/clients/http/filter/BMPFilter.java
===================================================================
--- trunk/freenet/src/freenet/clients/http/filter/BMPFilter.java
(rev 0)
+++ trunk/freenet/src/freenet/clients/http/filter/BMPFilter.java
2009-04-18 19:33:36 UTC (rev 27016)
@@ -0,0 +1,201 @@
+/* This code is part of Freenet. It is distributed under the GNU General
+ * Public License, version 2 (or at your option any later version). See
+ * http://www.gnu.org/ for further details of the GPL. */
+package freenet.clients.http.filter;
+
+import java.io.BufferedInputStream;
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.HashMap;
+
+import freenet.l10n.L10n;
+import freenet.support.HTMLNode;
+import freenet.support.api.Bucket;
+import freenet.support.api.BucketFactory;
+import freenet.support.io.Closer;
+
+/**
+ * This class would verify whether the BMP header is valid or not
+ Reference:
+ http://www.fastgraph.com/help/bmp_header_format.html
+ http://en.wikipedia.org/wiki/BMP_file_format
+ */
+public class BMPFilter implements ContentDataFilter {
+
+
+ static final byte[] bmpHeaderwindows =
+ { (byte)'B', (byte)'M'};
+
+ static final byte[] bmpHeaderos2bArray =
+ { (byte)'B', (byte)'A'};
+
+ static final byte[] bmpHeaderos2cIcon =
+ { (byte)'C', (byte)'I'};
+
+
+ static final byte[] bmpHeaderos2cPointer =
+ { (byte)'C', (byte)'P'};
+
+
+ static final byte[] bmpHeaderos2Icon =
+ { (byte)'I', (byte)'C'};
+
+
+ static final byte[] bmpHeaderos2Pointer =
+ { (byte)'P', (byte)'T'};
+
+
+ private int unsignedByte(byte b)
+ {
+ if (b >= 0)
+ return b;
+ else
+ return 256+b;
+ }
+
+
+ public int readInt(DataInputStream dis) throws IOException
+ {
+ int result;
+ byte[] data = new byte[4];
+
+ result = dis.read(data);
+ if (result < 0) // end of file reached
+ throw new EOFException();
+
+ result = (unsignedByte(data[2]) << 16) | (unsignedByte(data[1]) << 8) |
unsignedByte(data[0]);
+ result|=(unsignedByte(data[3]) << 24);
+
+ return result;
+ }
+
+
+ public int readShort(DataInputStream dis) throws IOException
+ {
+ int result = dis.read();
+ if (result < 0)// end of file reached
+ throw new EOFException();
+
+ int r2 = is.read();
+ if (r2 < 0)// end of file reached
+ throw new EOFException();
+
+ return result | (r2*256);
+ }
+
+
+ public Bucket readFilter(Bucket data, BucketFactory bf, String charset,
HashMap<String, String> otherParams,
+ FilterCallback cb) throws DataFilterException, IOException {
+ if(data.size() < 54) { // Size of the bmp header is 54
+ throwHeaderError(l10n("Too short file"), l10n("The file
is too short to contain a bmp header"));
+ }
+ InputStream is = data.getInputStream();
+ BufferedInputStream bis = new BufferedInputStream(is);
+ DataInputStream dis = new DataInputStream(bis);
+ try {
+
+ byte[] StartWord = new byte[2];
+ dis.readFully(StartWord);
+ if((!Arrays.equals(StartWord, bmpHeaderwindows)) &&
(!Arrays.equals(StartWord, bmpHeaderos2bArray)) && (!Arrays.equals(StartWord,
bmpHeaderos2cIcon)) && (!Arrays.equals(StartWord, bmpHeaderos2cPointer)) &&
(!Arrays.equals(StartWord, bmpHeaderos2Icon)) && (!Arrays.equals(StartWord,
bmpHeaderos2Pointer))) { //Checking the first word
+ throwHeaderError(l10n("Invalid start word"),
l10n("invalidHeader"));
+ }
+
+
+
+ int fileSize = readInt(dis); // read total file size
+ byte[] skipbytes=new byte[4];
+ dis.readFully(skipbytes);
+ int headerSize = readInt(dis); // read file header size or pixel offset
+ if(headerSize<0) {
+ throwHeaderError(l10n("Invalid
offset"), l10n("Image has invalid pixel offset of "+headerSize));
+ }
+
+
+
+ int size_bitmapinfoheader=readInt(dis);
+ if(size_bitmapinfoheader!=40) {
+ throwHeaderError(l10n("Invalid Bit Map
info header size"), l10n("Size of bitmap info header is not 40"));
+ }
+
+
+ int imageWidth = readInt(dis); // read width
+ int imageHeight = readInt(dis); // read height
+ if(imageWidth<0 || imageHeight<0) {
+ throwHeaderError(l10n("Invalid
Dimensions"), l10n("The image has invalid width or height"));
+ }
+
+
+
+ int no_plane=readShort(dis);
+ if(no_plane!=1) { // No of planes should be 1
+ throwHeaderError(l10n("Invalid no of
plannes"), l10n("The image has "+no_plane+" planes"));
+ }
+
+
+ int bitDepth = readShort(dis);
+
+ // Bit depth should be 1,2,4,8,16 or 32.
+ if(bitDepth!=1 && bitDepth!=2 && bitDepth!=4 && bitDepth!=8 &&
bitDepth!=16 && bitDepth!=24 && bitDepth!=32) {
+ throwHeaderError(l10n("Invalid bit
depth"), l10n("The bit depth field is set to"+bitDepth+". It is not of
1,2,4,8,16, and 32."));
+ }
+
+ int compression_type=readInt(dis);
+ if( !(compression_type>=0 && compression_type<=3) ) {
+ throwHeaderError(l10n("Invalid
Compression type"), l10n("Compression type field is set to "+compression_type+"
instead of 0-3"));
+ }
+
+ int imagedatasize=readInt(dis);
+ if(fileSize!=headerSize+imagedatasize) {
+ throwHeaderError(l10n("Invalid File
size"), l10n("File size is not matching to headersize+ imagedatasize"));
+ }
+
+ int horizontal_resolution=readInt(dis);
+ int vertical_resolution=readInt(dis);
+
+ if(horizontal_resolution<0 || vertical_resolution<0) {
+ throwHeaderError(l10n("Invalid resolution"),
l10n("This image file has resolution of
"+horizontal_resolution+"x"+vertical_resolution ));
+ }
+ if(compression_type==0) {
+ // Verifying the file size w.r.t. image dimensions(width and
height), bitDepth with imagedatasize(including padding).
+ int
bytesperline=(int)Math.ceil((imageWidth*bitDepth)/8);
+ int paddingperline=0;
+ if(bytesperline%4!=0) {
+ paddingperline=4-bytesperline%4;
+ }
+ int calculatedsize=
(int)Math.ceil((imageWidth*imageHeight*bitDepth)/8)+paddingperline*imageHeight;
+ if(calculatedsize!=imagedatasize) {
+ throwHeaderError(l10n("Invalid size of
image data"), l10n("The calculated image data size ("+calculatedsize+") is not
matching with the actual size ("+imagedatasize+")" ));
+ }
+ }
+
+
+
+ dis.close();
+ } finally {
+ Closer.close(dis);
+ }
+ return data;
+ }
+
+ private static String l10n(String key) {
+ return L10n.getString("BMPFilter."+key);
+ }
+
+ private void throwHeaderError(String shortReason, String reason) throws
DataFilterException {
+ // Throw an exception
+ String message = l10n("notBMP");
+ if(reason != null) message += ' ' + reason;
+ if(shortReason != null)
+ message += " - (" + shortReason + ')';
+ throw new DataFilterException(shortReason, shortReason,
+ "<p>"+message+"</p>", new
HTMLNode("p").addChild("#", message));
+ }
+
+ public Bucket writeFilter(Bucket data, BucketFactory bf, String
charset, HashMap<String, String> otherParams,
+ FilterCallback cb) throws DataFilterException, IOException {
+ return null;
+ }
+
+}
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