1 files changed, 162 insertions, 0 deletions
diff --git a/libtiled/compression.cpp b/libtiled/compression.cpp
new file mode 100644
index 0000000..3cf6f46
--- /dev/null
+++ b/libtiled/compression.cpp
@@ -0,0 +1,162 @@
+/*
+ * compression.cpp
+ * Copyright 2008, Thorbjørn Lindeijer <thorbjorn@lindeijer.nl>
+ *
+ * This file is part of libtiled.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice,
+ *       this list of conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "compression.h"
+
+#include <zlib.h>
+#include <QByteArray>
+#include <QDebug>
+
+using namespace Tiled;
+
+// TODO: Improve error reporting by showing these errors in the user interface
+static void logZlibError(int error)
+{
+    switch (error)
+    {
+        case Z_MEM_ERROR:
+            qDebug() << "Out of memory while (de)compressing data!";
+            break;
+        case Z_VERSION_ERROR:
+            qDebug() << "Incompatible zlib version!";
+            break;
+        case Z_NEED_DICT:
+        case Z_DATA_ERROR:
+            qDebug() << "Incorrect zlib compressed data!";
+            break;
+        default:
+            qDebug() << "Unknown error while (de)compressing data!";
+    }
+}
+
+QByteArray Tiled::decompress(const QByteArray &data, int expectedSize)
+{
+    QByteArray out;
+    out.resize(expectedSize);
+    z_stream strm;
+
+    strm.zalloc = Z_NULL;
+    strm.zfree = Z_NULL;
+    strm.opaque = Z_NULL;
+    strm.next_in = (Bytef *) data.data();
+    strm.avail_in = data.length();
+    strm.next_out = (Bytef *) out.data();
+    strm.avail_out = out.size();
+
+    int ret = inflateInit2(&strm, 15 + 32);
+
+    if (ret != Z_OK) {
+        logZlibError(ret);
+        return QByteArray();
+    }
+
+    do {
+        ret = inflate(&strm, Z_SYNC_FLUSH);
+
+        switch (ret) {
+            case Z_NEED_DICT:
+            case Z_STREAM_ERROR:
+                ret = Z_DATA_ERROR;
+            case Z_DATA_ERROR:
+            case Z_MEM_ERROR:
+                inflateEnd(&strm);
+                logZlibError(ret);
+                return QByteArray();
+        }
+
+        if (ret != Z_STREAM_END) {
+            int oldSize = out.size();
+            out.resize(out.size() * 2);
+
+            strm.next_out = (Bytef *)(out.data() + oldSize);
+            strm.avail_out = oldSize;
+        }
+    }
+    while (ret != Z_STREAM_END);
+
+    if (strm.avail_in != 0) {
+        logZlibError(Z_DATA_ERROR);
+        return QByteArray();
+    }
+
+    const int outLength = out.size() - strm.avail_out;
+    inflateEnd(&strm);
+
+    out.resize(outLength);
+    return out;
+}
+
+QByteArray Tiled::compress(const QByteArray &data, CompressionMethod method)
+{
+    QByteArray out;
+    out.resize(1024);
+    int err;
+    z_stream strm;
+    strm.zalloc = Z_NULL;
+    strm.zfree = Z_NULL;
+    strm.opaque = Z_NULL;
+    strm.next_in = (Bytef *) data.data();
+    strm.avail_in = data.length();
+    strm.next_out = (Bytef *) out.data();
+    strm.avail_out = out.size();
+
+    const int windowBits = (method == Gzip) ? 15 + 16 : 15;
+
+    err = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED, windowBits,
+                       8, Z_DEFAULT_STRATEGY);
+    if (err != Z_OK) {
+        logZlibError(err);
+        return QByteArray();
+    }
+
+    do {
+        err = deflate(&strm, Z_FINISH);
+        Q_ASSERT(err != Z_STREAM_ERROR);
+
+        if (err == Z_OK) {
+            // More output space needed
+            int oldSize = out.size();
+            out.resize(out.size() * 2);
+
+            strm.next_out = (Bytef *)(out.data() + oldSize);
+            strm.avail_out = oldSize;
+        }
+    } while (err == Z_OK);
+
+    if (err != Z_STREAM_END) {
+        logZlibError(err);
+        deflateEnd(&strm);
+        return QByteArray();
+    }
+
+    const int outLength = out.size() - strm.avail_out;
+    deflateEnd(&strm);
+
+    out.resize(outLength);
+    return out;
+}