Implement base64 stdlib

opal · Dec 19, 2013 · 6b643f4 · 6b643f4
1 parent 1f6506b
commit 6b643f4
Showing 1 changed file with 152 additions and 0 deletions.
diff --git a/stdlib/base64.rb b/stdlib/base64.rb
@@ -0,0 +1,152 @@
+module Base64
+  %x{
+    var charset = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=',
+        lookup  = {};
+
+    for (var i = 0, length = charset.length; i < length; i++) {
+      lookup[charset.charAt(i)] = i;
+    }
+
+    function from(string) {
+      var buffer = [];
+
+      for (var i = 0, length = string.length; i < length; i++) {
+        var a, b, c, d;
+
+        a = lookup[string.charAt(i)];
+        b = lookup[string.charAt(++i)];
+
+        buffer.push((a << 2) | (b >> 4));
+
+        c = lookup[string.charAt(++i)];
+
+        if (c == 64) {
+          break;
+        }
+
+        buffer.push(((b & 15) << 4) | (c >> 2));
+
+        d = lookup[string.charAt(++i)];
+
+        if (d == 64) {
+          break;
+        }
+
+        buffer.push(((c & 3) << 6) | d);
+      }
+
+      return buffer;
+    }
+
+    function decode(string) {
+      var buffer = from(string),
+          result = [];
+
+      for (var i = 0, length = buffer.length; i < length; i++) {
+        if (buffer[i] < 128) {
+          result.push(String.fromCharCode(buffer[i]));
+        }
+        else if (buffer[i] > 191 && buffer[i] < 224) {
+          var a = (buffer[i] & 31) << 6,
+              b = buffer[++i] & 63;
+
+          result.push(String.fromCharCode(a | b));
+        }
+        else {
+          var a = (buffer[i] & 15) << 12,
+              b = (buffer[++i] & 63) << 6,
+              c = buffer[++i] & 63;
+
+          result.push(String.fromCharCode(a | b | c));
+        }
+      }
+
+      return result.join('');
+    }
+
+    function to(string) {
+      var buffer = [];
+
+      if (/^[\x00-\x7f]*$/.test(string)) {
+        for (var i = 0, length = string.length; i < length; i++) {
+          buffer.push(string.charCodeAt(i));
+        }
+      }
+      else {
+        for (var i = 0, length = string.length; i < length; i++) {
+          var ch = string.charCodeAt(i);
+
+          if (ch < 128) {
+            buffer.push(ch);
+          }
+          else if (ch < 2048) {
+            buffer.push((ch >> 6) | 192);
+            buffer.push((ch & 63) | 128);
+          }
+          else {
+            buffer.push((ch >> 12) | 224);
+            buffer.push(((ch >> 6) & 63) | 128);
+            buffer.push((ch & 63) | 128);
+          }
+        }
+      }
+
+      return buffer;
+    }
+
+    function encode(string) {
+      var buffer = to(string),
+          result = [];
+
+      for (var i = 0, length = buffer.length; i < length; i++) {
+        var a = buffer[i],
+            b = buffer[++i],
+            c = 0,
+            d = a >> 2,
+            e = ((a & 3) << 4) | (b >> 4),
+            f = 0,
+            g = 0;
+
+        if (isNaN(a)) {
+          f = g = 64;
+        }
+        else {
+          c = buffer[++i];
+          f = ((b & 15) << 2) | (c >> 6);
+          g = isNaN(c) ? 64 : c & 63;
+        }
+
+        result.push(charset.charAt(d));
+        result.push(charset.charAt(e));
+        result.push(charset.charAt(f));
+        result.push(charset.charAt(g));
+      }
+
+      return result.join('');
+    }
+  }
+
+  def self.decode64(string)
+    `decode(string.replace(/\r?\n/g, ''))`
+  end
+
+  def self.encode64(string)
+    `encode(string).replace(/(.{60})/g, "$1\n")`
+  end
+
+  def self.strict_decode64(string)
+    `decode(string)`
+  end
+
+  def self.strict_encode64(string)
+    `encode(string)`
+  end
+
+  def self.urlsafe_decode64(string)
+    `decode(string.replace(/\-/g, '+').replace(/_/g, '/'))`
+  end
+
+  def self.urlsafe_encode64(string)
+    `encode(string).replace(/\+/g, '-').replace(/\//g, '_')`
+  end
+end