Allowing raw images to be read from a stream.

git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@758 ed5b42cb-e716-0410-a449-f6a68f950b19

src/java/com/threerings/resource/FastImageIO.java

@@ -24,9 +24,11 @@ package com.threerings.resource;
 import java.io.DataOutputStream;
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.RandomAccessFile;
 
+import java.nio.ByteBuffer;
 import java.nio.IntBuffer;
 import java.nio.MappedByteBuffer;
 import java.nio.channels.FileChannel;
@@ -39,6 +41,8 @@ import java.awt.image.IndexColorModel;
 import java.awt.image.PixelInterleavedSampleModel;
 import java.awt.image.WritableRaster;
 
+import org.apache.commons.io.IOUtils;
+
 /**
  * Provides routines for writing and reading uncompressed 8-bit color
  * mapped images in a manner that is extremely fast and generates a
@@ -46,7 +50,9 @@ import java.awt.image.WritableRaster;
  */
 public class FastImageIO
 {
-    /** A suffix for use when storing raw images in bundles or on the file system. */
+    /**
+     * A suffix for use when storing raw images in bundles or on the file system.
+     */
     public static final String FILE_SUFFIX = ".raw";
 
     /**
@@ -112,51 +118,74 @@ public class FastImageIO
 
         try {
             MappedByteBuffer mbuf = fchan.map(FileChannel.MapMode.READ_ONLY, 0, file.length());
-
-            // read in our integer fields
-            IntBuffer ibuf = mbuf.asIntBuffer();
-            int width = ibuf.get();
-            int height = ibuf.get();
-            /* int tpixel = */ ibuf.get();
-            int msize = ibuf.get();
-
-            if (width > Short.MAX_VALUE || width < 0 || height > Short.MAX_VALUE || height < 0) {
-                throw new IOException("Bogus image size " + width + "x" + height);
-            }
-
-            IndexColorModel cmodel;
-            synchronized (_origin) { // any old object will do
-                // make sure our colormap array is big enough
-                if  (_cmap == null || _cmap.length < msize) {
-                    _cmap = new int[msize];
-                }
-                // read in the data and create our colormap
-                ibuf.get(_cmap, 0, msize);
-                cmodel = new IndexColorModel(8, msize, _cmap, 0, DataBuffer.TYPE_BYTE, null);
-            }
-
-            // advance the byte buffer accordingly
-            mbuf.position(ibuf.position() * 4);
-
-            // read in the image data itself
-            byte[] data = new byte[width*height];
-            mbuf.get(data);
-
-            // create the image from our component parts
-            DataBuffer dbuf = new DataBufferByte(data, data.length, 0);
-            int[] offsets = new int[] { 0 };
-            PixelInterleavedSampleModel smodel =
-                new PixelInterleavedSampleModel(
-                    DataBuffer.TYPE_BYTE, width, height, 1, width, offsets);
-            WritableRaster raster = WritableRaster.createWritableRaster(smodel, dbuf, _origin);
-            return new BufferedImage(cmodel, raster, false, null);
-
+            return read(mbuf);
         } finally {
             fchan.close();
             raf.close();
         }
     }
 
+    /**
+     * Reads an image from the supplied input stream (which must return the image format previously
+     * written via a call to {@link #write}).
+     *
+     * @exception IOException thrown if an error occurs reading from the file.
+     */
+    public static BufferedImage read (InputStream in)
+        throws IOException
+    {
+        return read(ByteBuffer.wrap(IOUtils.toByteArray(in)));
+    }
+
+    /**
+     * Reads an image from the supplied byte buffer (which must return the image format previously
+     * written via a call to {@link #write}).
+     *
+     * @exception IOException thrown if an error occurs reading from the file.
+     */
+    public static BufferedImage read (ByteBuffer byteBuffer)
+        throws IOException
+    {
+        // read in our integer fields
+        IntBuffer ibuf = byteBuffer.asIntBuffer();
+        int width = ibuf.get();
+        int height = ibuf.get();
+        /* int tpixel = */ ibuf.get();
+        int msize = ibuf.get();
+
+        if (width > Short.MAX_VALUE || width < 0 || height > Short.MAX_VALUE || height < 0) {
+            throw new IOException("Bogus image size " + width + "x" + height);
+        }
+
+        IndexColorModel cmodel;
+        synchronized (_origin) { // any old object will do
+            // make sure our colormap array is big enough
+            if  (_cmap == null || _cmap.length < msize) {
+                _cmap = new int[msize];
+            }
+            // read in the data and create our colormap
+            ibuf.get(_cmap, 0, msize);
+            cmodel = new IndexColorModel(
+                8, msize, _cmap, 0, DataBuffer.TYPE_BYTE, null);
+        }
+
+        // advance the byte buffer accordingly
+        byteBuffer.position(ibuf.position() * 4);
+
+        // read in the image data itself
+        byte[] data = new byte[width*height];
+        byteBuffer.get(data);
+
+        // create the image from our component parts
+        DataBuffer dbuf = new DataBufferByte(data, data.length, 0);
+        int[] offsets = new int[] { 0 };
+        PixelInterleavedSampleModel smodel =
+            new PixelInterleavedSampleModel(
+                DataBuffer.TYPE_BYTE, width, height, 1, width, offsets);
+        WritableRaster raster = WritableRaster.createWritableRaster(smodel, dbuf, _origin);
+        return new BufferedImage(cmodel, raster, false, null);
+    }
+
     /** Used when loading our color map. */
     protected static int[] _cmap;