Added WebMoira sources

[moira.git] / webmoira / mit / moira / Coder.java

diff --git a/webmoira/mit/moira/Coder.java b/webmoira/mit/moira/Coder.java
new file mode 100644 (file)
index 0000000..8ac1819
--- /dev/null
+++ b/webmoira/mit/moira/Coder.java
@@ -0,0 +1,146 @@
+package mit.moira;
+
+import java.util.Vector;
+import java.util.Enumeration;
+
+/**
+ * Class with static functions for base64 encoding and decoding as well
+ * as other utilities.
+ */
+
+public class Coder {
+  static final char encv[] = {
+    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
+    'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 
+    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
+    'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 
+    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' };
+  static char x2c (char [] what, int off) {
+    int digit;
+    digit = (what[off] >= 'A' ? ((what[off] & 0xdf) - 'A')+10 : (what[off] - '0'));
+    digit *= 16;
+    digit += (what[off+1] >= 'A' ? ((what[off+1] & 0xdf) - 'A')+10 : (what[off+1] - '0'));
+    return((char)digit);
+  }
+  
+  private Coder() {            // No Constructors...
+  }
+
+  /**
+   * Remove URL escape sequences
+   *
+   * @param aurl A String with potential embedded escapes.
+   * @return the String with the escapes removed.
+   */
+  public static String unescape_url(String aurl) {
+    int x, y, i;
+    char [] url = new char [aurl.length()];
+    aurl.getChars(0, aurl.length(), url, 0);
+    StringBuffer ret = new StringBuffer();
+    for (i = 0; i < url.length; i++) {
+      if (url[i] == '%') {
+       ret.append(x2c(url, i+1));
+       i += 2;
+      } else if (url[i] == '+') {
+       ret.append(' ');
+      } else ret.append(url[i]);
+    }
+    return (new String(ret));
+  }
+
+  /**
+   * Encodes a byte array in base64 characters and returns the result
+   * as a String.
+   *
+   * @param data the Byte array
+   * @return The encoded string
+   */
+
+  public static String encode(byte [] data) {
+    StringBuffer ret = new StringBuffer();
+    int len = data.length;
+    int c;
+    int p = 0;
+    int i = 0;
+    int nib1, nib2, nib3, nib4;
+    while (i < len) {
+      if ((i+3) <= len) {
+       c = (data[i++] & 0xFF);
+       c = (c << 8) | (data[i++] & 0xFF);
+       c = (c << 8) | (data[i++] & 0xFF);
+       nib1 = (c & 0x0FC0000) >>> 18;
+       nib2 = (c & 0x003F000) >>> 12;
+       nib3 = (c & 0x0000FC0) >>> 6;
+       nib4 = (c & 0x000003F);
+       ret.append(encv[nib1]);
+       ret.append(encv[nib2]);
+       ret.append(encv[nib3]);
+       ret.append(encv[nib4]);
+      } else {
+       p = len - i;
+       c = data[i++];
+       c = c << 8;
+       if (p > 1) c |= (data[i++] & 0xFF);
+       c = c << 8;
+       if (p > 2) c |= (data[i++] & 0xFF); // Should never happen
+       nib1 = (c & 0x0FC0000) >>> 18;
+       nib2 = (c & 0x003F000) >>> 12;
+       nib3 = (c & 0x0000FC0) >>> 6;
+       nib4 = (c & 0x000003F);
+       ret.append(encv[nib1]);
+       ret.append(encv[nib2]);
+       if (p == 1) ret.append('=');
+       else ret.append(encv[nib3]);
+       ret.append('=');
+      }
+    }
+    return (new String(ret));
+  }
+
+  /**
+   * Decodes a base64 encoded string and returns the decoded value
+   * in a byte array.
+   *
+   * @param s The base64 encoded string
+   * @return the byte array decoded
+   */
+  public static byte [] decode (String s) {
+    Vector v = new Vector();
+    int p = 0;
+    int i = 0;
+    int k = 0;
+    int z = 0;
+    int reg = 0;
+    for (i = 0; i < s.length(); i++) {
+      char c = s.charAt(i);
+      if (c == '/') z = 63;
+      else if (c == '+') z = 62;
+      else if ((c >= 'a') && (c <= 'z')) z = (c - 'a') + 26;
+      else if ((c >= 'A') && (c <= 'Z')) z = (c - 'A');
+      else if ((c >= '0') && (c <= '9')) z = (c - '0') + 52;
+      else if (c == '=') {
+       p++;
+       z = 0;
+      } else continue;
+      reg <<= 6;
+      reg += z;
+      k++;
+      if (k == 4) {
+       for (z = 0; z < 3; z++) {
+         v.addElement(new Integer((reg & 0xff0000) >>> 16));
+         reg = (reg << 8);
+       }
+       k = 0;
+      }
+    }
+    Enumeration e = v.elements();
+    byte [] retval = new byte[v.size() - p];
+    for(i = 0; i < v.size() - p; i++) {
+      retval[i] = ((Integer) e.nextElement()).byteValue();
+    }
+    return (retval);
+  }
+}
+      
+      
+