Import Upstream version 0.4.0~beta1

1 files changed, 191 insertions, 0 deletions

diff --git a/src/de/lmu/ifi/dbs/elki/utilities/FileUtil.java b/src/de/lmu/ifi/dbs/elki/utilities/FileUtil.java
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+++ b/src/de/lmu/ifi/dbs/elki/utilities/FileUtil.java
@@ -0,0 +1,191 @@
+package de.lmu.ifi.dbs.elki.utilities;
+/*
+This file is part of ELKI:
+Environment for Developing KDD-Applications Supported by Index-Structures
+
+Copyright (C) 2011
+Ludwig-Maximilians-Universität München
+Lehr- und Forschungseinheit für Datenbanksysteme
+ELKI Development Team
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program 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 Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.PushbackInputStream;
+import java.util.zip.GZIPInputStream;
+
+/**
+ * Various static helper methods to deal with files and file names.
+ * 
+ * @author Erich Schubert
+ */
+public final class FileUtil {
+  /**
+   * Returns the lower case extension of the selected file.
+   * 
+   * If no file is selected, <code>null</code> is returned.
+   * 
+   * @param file File object
+   * @return Returns the extension of the selected file in lower case or
+   *         <code>null</code>
+   */
+  public static String getFilenameExtension(File file) {
+    return getFilenameExtension(file.getName());
+  }
+
+  /**
+   * Returns the lower case extension of the selected file.
+   * 
+   * If no file is selected, <code>null</code> is returned.
+   * 
+   * @param name File name
+   * @return Returns the extension of the selected file in lower case or
+   *         <code>null</code>
+   */
+  public static String getFilenameExtension(String name) {
+    if(name == null) {
+      return null;
+    }
+    int index = name.lastIndexOf(".");
+    if(index >= name.length() - 1) {
+      return null;
+    }
+    return name.substring(name.lastIndexOf(".") + 1).toLowerCase();
+  }
+
+  /**
+   * Try to open a file, first trying the file system,
+   * then falling back to the classpath.
+   * 
+   * @param filename File name in system notation
+   * @return Input stream
+   * @throws FileNotFoundException When no file was found.
+   */
+  public static InputStream openSystemFile(String filename) throws FileNotFoundException {
+    try {
+      return new FileInputStream(filename);
+    }
+    catch(FileNotFoundException e) {
+      // try with classloader
+      String resname = filename.replace(File.separatorChar, '/');
+      InputStream result = ClassLoader.getSystemResourceAsStream(resname);
+      if (result == null) {
+        throw e;
+      }
+      return result;
+    }
+  }
+
+  /**
+   * Try to open a stream as gzip, if it starts with the gzip magic.
+   * 
+   * TODO: move to utils package.
+   * 
+   * @param in original input stream
+   * @return old input stream or a {@link GZIPInputStream} if appropriate.
+   * @throws IOException on IO error
+   */
+  public static InputStream tryGzipInput(InputStream in) throws IOException {
+    // try autodetecting gzip compression.
+    if (!in.markSupported()) {
+      PushbackInputStream pb = new PushbackInputStream(in, 16);
+      in = pb;
+      // read a magic from the file header
+      byte[] magic = {0, 0};
+      pb.read(magic);
+      pb.unread(magic);
+      if (magic[0] == 31 && magic[1] == -117) {
+        in = new GZIPInputStream(pb);
+      }
+    } else
+    if (in.markSupported()) {
+      in.mark(16);
+      if (in.read() == 31 && in.read() == -117) {
+        in.reset();
+        in = new GZIPInputStream(in);
+      } else {
+        // just rewind the stream
+        in.reset();
+      }
+    }
+    return in;
+  }
+
+  /**
+   * Try to locate an file in the filesystem, given a partial name and a prefix.
+   * 
+   * @param name file name
+   * @param basedir extra base directory to try
+   * @return file, if the file could be found. {@code null} otherwise
+   */
+  public static File locateFile(String name, String basedir) {
+    // Try exact match first.
+    File f = new File(name);
+    if(f.exists()) {
+      return f;
+    }
+    // Try with base directory
+    if(basedir != null) {
+      f = new File(basedir, name);
+      // logger.warning("Trying: "+f.getAbsolutePath());
+      if(f.exists()) {
+        return f;
+      }
+    }
+    // try stripping whitespace
+    {
+      String name2 = name.trim();
+      if(!name.equals(name2)) {
+        // logger.warning("Trying without whitespace.");
+        f = locateFile(name2, basedir);
+        if(f != null) {
+          return f;
+        }
+      }
+    }
+    // try substituting path separators
+    {
+      String name2 = name.replace('/',File.separatorChar);
+      if (!name.equals(name2)) {
+        // logger.warning("Trying with replaced separators.");
+        f = locateFile(name2, basedir);
+        if(f != null) {
+          return f;
+        }
+      }
+      name2 = name.replace('\\',File.separatorChar);
+      if (!name.equals(name2)) {
+        // logger.warning("Trying with replaced separators.");
+        f = locateFile(name2, basedir);
+        if(f != null) {
+          return f;
+        }
+      }
+    }
+    // try stripping extra characters, such as quotes.
+    if(name.length() > 2 && name.charAt(0) == '"' && name.charAt(name.length() - 1) == '"') {
+      // logger.warning("Trying without quotes.");
+      f = locateFile(name.substring(1, name.length() - 1), basedir);
+      if(f != null) {
+        return f;
+      }
+    }
+    return null;
+  }
+}