Initial revision

From-SVN: r102074

libjava/classpath/java/net/URLEncoder.java

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+/* URLEncoder.java -- Class to convert strings to a properly encoded URL
+   Copyright (C) 1998, 1999, 2001, 2002, 2003 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath 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
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+package java.net;
+
+import java.io.UnsupportedEncodingException;
+
+
+/*
+ * Written using on-line Java Platform 1.2/1.4 API Specification, as well
+ * as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998).
+ * Status:  Believed complete and correct.
+ */
+
+/**
+ * This utility class contains static methods that converts a
+ * string into a fully encoded URL string in x-www-form-urlencoded
+ * format.  This format replaces certain disallowed characters with
+ * encoded equivalents.  All upper case and lower case letters in the
+ * US alphabet remain as is, the space character (' ') is replaced with
+ * '+' sign, and all other characters are converted to a "%XX" format
+ * where XX is the hexadecimal representation of that character in a
+ * certain encoding (by default, the platform encoding, though the
+ * standard is "UTF-8").
+ * <p>
+ * This method is very useful for encoding strings to be sent to CGI scripts
+ *
+ * @author Aaron M. Renn (arenn@urbanophile.com)
+ * @author Warren Levy (warrenl@cygnus.com)
+ * @author Mark Wielaard (mark@klomp.org)
+ */
+public class URLEncoder
+{
+  /**
+   * This method translates the passed in string into x-www-form-urlencoded
+   * format using the default encoding.  The standard encoding is
+   * "UTF-8", and the two-argument form of this method should be used
+   * instead.
+   *
+   * @param s The String to convert
+   *
+   * @return The converted String
+   *
+   * @deprecated
+   */
+  public static String encode(String s)
+  {
+    try
+      {
+	// We default to 8859_1 for compatibility with the same
+	// default elsewhere in the library.
+	return encode(s, System.getProperty("file.encoding", "8859_1"));
+      }
+    catch (UnsupportedEncodingException uee)
+      {
+	// Should never happen since default should always be supported
+	return s;
+      }
+  }
+
+  /**
+   * This method translates the passed in string into x-www-form-urlencoded
+   * format using the character encoding to hex-encode the unsafe characters.
+   *
+   * @param s The String to convert
+   * @param encoding The encoding to use for unsafe characters
+   *
+   * @return The converted String
+   *
+   * @exception UnsupportedEncodingException If the named encoding is not
+   * supported
+   *
+   * @since 1.4
+   */
+  public static String encode(String s, String encoding)
+    throws UnsupportedEncodingException
+  {
+    int length = s.length();
+    int start = 0;
+    int i = 0;
+
+    StringBuffer result = new StringBuffer(length);
+    while (true)
+      {
+	while (i < length && isSafe(s.charAt(i)))
+	  i++;
+
+	// Safe character can just be added
+	result.append(s.substring(start, i));
+
+	// Are we done?
+	if (i >= length)
+	  return result.toString();
+	else if (s.charAt(i) == ' ')
+	  {
+	    result.append('+'); // Replace space char with plus symbol.
+	    i++;
+	  }
+	else
+	  {
+	    // Get all unsafe characters
+	    start = i;
+	    char c;
+	    while (i < length && (c = s.charAt(i)) != ' ' && ! isSafe(c))
+	      i++;
+
+	    // Convert them to %XY encoded strings
+	    String unsafe = s.substring(start, i);
+	    byte[] bytes = unsafe.getBytes(encoding);
+	    for (int j = 0; j < bytes.length; j++)
+	      {
+		result.append('%');
+		int val = bytes[j];
+		result.append(hex.charAt((val & 0xf0) >> 4));
+		result.append(hex.charAt(val & 0x0f));
+	      }
+	  }
+	start = i;
+      }
+  }
+
+  /**
+   * Private static method that returns true if the given char is either
+   * a uppercase or lowercase letter from 'a' till 'z', or a digit froim
+   * '0' till '9', or one of the characters '-', '_', '.' or '*'. Such
+   * 'safe' character don't have to be url encoded.
+   */
+  private static boolean isSafe(char c)
+  {
+    return ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')
+           || (c >= '0' && c <= '9') || c == '-' || c == '_' || c == '.'
+           || c == '*');
+  }
+
+  /**
+   * Private constructor that does nothing. Included to avoid a default
+   * public constructor being created by the compiler.
+   */
+  private URLEncoder()
+  {
+  }
+
+  /**
+   * Used to convert to hex.  We don't use Integer.toHexString, since
+   * it converts to lower case (and the Sun docs pretty clearly
+   * specify upper case here), and because it doesn't provide a
+   * leading 0.
+   */
+  private static final String hex = "0123456789ABCDEF";
+}