added org.ibex.util.FileNameEncoder: safely escapes filenames

darcs-hash:20040509232643-5007d-b64121307daab8d7a2e2c8772c338ca30943215e.gz

diff --git a/src/org/ibex/util/FileNameEncoder.java b/src/org/ibex/util/FileNameEncoder.java
new file mode 100644 (file)
index 0000000..e68bba2
--- /dev/null
+++ b/src/org/ibex/util/FileNameEncoder.java
@@ -0,0 +1,50 @@
+// Copyright (C) 2003 Adam Megacz <adam@ibex.org> all rights reserved.
+//
+// You may modify, copy, and redistribute this code under the terms of
+// the GNU Library Public License version 2.1, with the exception of
+// the portion of clause 6a after the semicolon (aka the "obnoxious
+// relink clause")
+
+package org.ibex.util;
+import java.util.*;
+import java.io.*;
+
+/** provides commands to urlencode and urldecode strings, making sure
+ *  to escape sequences which have special meanings in filenames */
+public class FileNameEncoder {
+
+    private static final char[] hex =
+        new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
+
+    public static String encode(String s) {
+        StringBuffer sb = new StringBuffer();
+        try {
+            byte[] b = s.getBytes("UTF-8");
+            for(int i=0; i<b.length; i++) {
+                char c = (char)(b[i] & 0xff);
+                if (c == File.separatorChar || c < 32 || c > 126 || c == '%' || (i == 0 && c == '.'))
+                    sb.append("%" + hex[(b[i] & 0xf0) >> 8] + hex[b[i] & 0xf]);
+                else sb.append(c);
+            }
+            return sb.toString();
+        } catch (UnsupportedEncodingException uee) {
+            throw new Error("this should never happen; Java spec mandates UTF-8 support");
+        }
+    }
+
+    public static String decode(String s) {
+        StringBuffer sb = new StringBuffer();
+        byte[] b = new byte[s.length() * 2];
+        int bytes = 0;
+        for(int i=0; i<s.length(); i++) {
+            char c = s.charAt(i);
+            if (c == '%') b[bytes++] = (byte)Integer.parseInt(("" + s.charAt(++i) + s.charAt(++i)), 16);
+            else b[bytes++] = (byte)c;
+        }
+        try {
+            return new String(b, 0, bytes, "UTF-8");
+        } catch (UnsupportedEncodingException uee) {
+            throw new Error("this should never happen; Java spec mandates UTF-8 support");
+        }
+    }
+}