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diff --git a/lz.js b/lz.js
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+"use strict";
+/*
+   Copyright (C) 2012 by Jeremy P. White <jwhite@codeweavers.com>
+
+   This file is part of spice-html5.
+
+   spice-html5 is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   spice-html5 is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with spice-html5.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+
+/*----------------------------------------------------------------------------
+**  lz.js
+**      Functions for handling SPICE_IMAGE_TYPE_LZ_RGB
+**  Adapted from lz.c .
+**--------------------------------------------------------------------------*/
+function lz_rgb32_decompress(in_buf, at, out_buf, type, default_alpha)
+{
+    var encoder = at;
+    var op = 0;
+    var ctrl;
+    var ctr = 0;
+
+    for (ctrl = in_buf[encoder++]; (op * 4) < out_buf.length; ctrl = in_buf[encoder++])
+    {
+        var ref = op;
+        var len = ctrl >> 5;
+        var ofs = (ctrl & 31) << 8;
+
+//if (type == LZ_IMAGE_TYPE_RGBA)
+//console.log(ctr++ + ": from " + (encoder + 28) + ", ctrl " + ctrl + ", len " + len + ", ofs " + ofs + ", op " + op);
+        if (ctrl >= 32) {
+
+            var code;
+            len--;
+
+            if (len == 7 - 1) {
+                do {
+                    code = in_buf[encoder++];
+                    len += code;
+                } while (code == 255);
+            }
+            code = in_buf[encoder++];
+            ofs += code;
+
+
+            if (code == 255) {
+                if ((ofs - code) == (31 << 8)) {
+                    ofs = in_buf[encoder++] << 8;
+                    ofs += in_buf[encoder++];
+                    ofs += 8191;
+                }
+            }
+            len += 1;
+            if (type == LZ_IMAGE_TYPE_RGBA)
+                len += 2;
+
+            ofs += 1;
+
+            ref -= ofs;
+            if (ref == (op - 1)) {
+                var b = ref;
+//if (type == LZ_IMAGE_TYPE_RGBA) console.log("alpha " + out_buf[(b*4)+3] + " dupped into pixel " + op + " through pixel " + (op + len));
+                for (; len; --len) {
+                    if (type == LZ_IMAGE_TYPE_RGBA)
+                    {
+                        out_buf[(op*4) + 3] = out_buf[(b*4)+3];
+                    }
+                    else
+                    {
+                        for (i = 0; i < 4; i++)
+                            out_buf[(op*4) + i] = out_buf[(b*4)+i];
+                    }
+                    op++;
+                }
+            } else {
+//if (type == LZ_IMAGE_TYPE_RGBA) console.log("alpha copied to pixel " + op + " through " + (op + len) + " from " + ref);
+                for (; len; --len) {
+                    if (type == LZ_IMAGE_TYPE_RGBA)
+                    {
+                        out_buf[(op*4) + 3] = out_buf[(ref*4)+3];
+                    }
+                    else
+                    {
+                        for (i = 0; i < 4; i++)
+                            out_buf[(op*4) + i] = out_buf[(ref*4)+i];
+                    }
+                    op++; ref++;
+                }
+            }
+        } else {
+            ctrl++;
+
+            if (type == LZ_IMAGE_TYPE_RGBA)
+            {
+//console.log("alpha " + in_buf[encoder] + " set into pixel " + op);
+                out_buf[(op*4) + 3] = in_buf[encoder++];
+            }
+            else
+            {
+                out_buf[(op*4) + 0] = in_buf[encoder + 2];
+                out_buf[(op*4) + 1] = in_buf[encoder + 1];
+                out_buf[(op*4) + 2] = in_buf[encoder + 0];
+                if (default_alpha)
+                    out_buf[(op*4) + 3] = 255;
+                encoder += 3;
+            }
+            op++;
+
+
+            for (--ctrl; ctrl; ctrl--) {
+                if (type == LZ_IMAGE_TYPE_RGBA)
+                {
+//console.log("alpha " + in_buf[encoder] + " set into pixel " + op);
+                    out_buf[(op*4) + 3] = in_buf[encoder++];
+                }
+                else
+                {
+                    out_buf[(op*4) + 0] = in_buf[encoder + 2];
+                    out_buf[(op*4) + 1] = in_buf[encoder + 1];
+                    out_buf[(op*4) + 2] = in_buf[encoder + 0];
+                    if (default_alpha)
+                        out_buf[(op*4) + 3] = 255;
+                    encoder += 3;
+                }
+                op++;
+            }
+        }
+
+    }
+    return encoder - 1;
+}
+
+function convert_spice_lz_rgb_to_web(context, lz_rgb)
+{
+    var u8 = new Uint8Array(lz_rgb.data);
+    var at;
+    if (lz_rgb.type != LZ_IMAGE_TYPE_RGB32 && lz_rgb.type != LZ_IMAGE_TYPE_RGBA)
+        return undefined;
+
+    var ret = context.createImageData(lz_rgb.width, lz_rgb.height);
+
+    at = lz_rgb32_decompress(u8, 0, ret.data, LZ_IMAGE_TYPE_RGB32, lz_rgb.type != LZ_IMAGE_TYPE_RGBA);
+    if (lz_rgb.type == LZ_IMAGE_TYPE_RGBA)
+        lz_rgb32_decompress(u8, at, ret.data, LZ_IMAGE_TYPE_RGBA, false);
+
+    return ret;
+}