WebDriver bindings.

pkg/webdriver/base64decoder.dart

Index: pkg/webdriver/base64decoder.dart
===================================================================
--- pkg/webdriver/base64decoder.dart	(revision 0)
+++ pkg/webdriver/base64decoder.dart	(revision 0)
@@ -0,0 +1,49 @@
+/**
+ * A simple base64 decoder class, used to decode web browser screenshots
+ * returned by WebDriver.
+ */
+class Base64Decoder {
+
+  static int getVal(String s, pos) {
+    int code = s.charCodeAt(pos);
+    if (code >= 65 && code < (65+26)) { // 'A'..'Z'
+      return code - 65;
+    } else if (code >= 97 && code < (97+26)) { // 'a'..'z'
+      return code - 97 + 26;
+    } else if (code >= 48 && code < (48+10)) { // '0'..'9'
+      return code - 48 + 52;
+    } else if (code == 43) { // '+'
+      return 62;
+    } else if (code == 47) { // '/'
+      return 63;
+    } else {
+      throw 'Invalid character $s';
+    }
+  }
+
+  static List<int> decode(String s) {
+    var rtn = new List<int>();
+    var pos = 0;
+    while (pos < s.length) {
+      if (s[pos+2] =='=') { // Single byte as two chars.
+        int v = (getVal(s, pos) << 18 ) | (getVal(s, pos+1) << 12 );
+        rtn.add((v >> 16) & 0xff);
+        break;
+      } else if (s[pos+3] == '=') { // Two bytes as 3 chars.
+        int v = (getVal(s, pos) << 18 ) | (getVal(s, pos+1) << 12 ) |
+            (getVal(s, pos + 2) << 6);
+        rtn.add((v >> 16) & 0xff);
+        rtn.add((v >> 8) & 0xff);
+        break;
+      } else { // Three bytes as 4 chars.
+        int v = (getVal(s, pos) << 18 ) | (getVal(s, pos+1) << 12 ) |
+            (getVal(s, pos + 2) << 6) | getVal(s, pos+3);
+        pos += 4;
+        rtn.add((v >> 16 ) & 0xff);
+        rtn.add((v >> 8) & 0xff);
+        rtn.add(v & 0xff);
+      }
+    }
+    return rtn;
+  }
+}