- Add lib/crypto.

crypto/crypto.dart

Index: crypto/crypto.dart
===================================================================
--- crypto/crypto.dart	(revision 0)
+++ crypto/crypto.dart	(revision 0)
@@ -0,0 +1,69 @@
+#library("crypto");

[Mads Ager (google), 2012/04/24 09:57:46]

Copyright.

[Ivan Posva, 2012/04/24 13:02:36]

Done.

+
+#source("sha1.dart");
+
+// Helpers used implementing the different crypto algorithms.

[Ivan Posva, 2012/04/24 09:23:53]

We might want to move these helpers into their own file if we feel like it and
only have the public interfaces in here once they have been defined.

[Mads Ager (google), 2012/04/24 09:57:46]

Yes, I can do that in the next round.

+
+final int _BITS_PER_BYTE = 8;
+final int _BYTES_PER_WORD = 4;
+final int _BITS_PER_WORD = _BITS_PER_BYTE * _BYTES_PER_WORD;
+final int _MASK_32 = 0xffffffff;
+
+int _roundUp(int val, int n) {
+  return (val + n - 1) & -n;
+}
+
+// Rotate left limiting to unsigned 32-bit values.
+int _rotl32(int val, int shift) {
+  var mod_shift = shift & 31;
+  return ((val << mod_shift) & _MASK_32) | ((val & _MASK_32) >> (32 - mod_shift));

[Mads Ager (google), 2012/04/24 09:57:46]

Long line.

[Ivan Posva, 2012/04/24 13:02:36]

Done.

+}
+
+// Add limiting to unsigned 32-bit values.
+int _add32(int left, int right) {
+  return (left + right) & _MASK_32;
+}
+
+void _bytesToWords(List<int> input,
+                   int in_offset,
+                   int in_len,
+                   List<int> output,
+                   int out_offset,
+                   int out_len) {
+  var cur = in_offset;
+  var end = in_offset + in_len;
+  var cur_out = out_offset;
+  var unroll_loop_end = in_len ~/ _BYTES_PER_WORD;
+  
+  while (cur_out < unroll_loop_end) {
+    var word = (input[cur++] & 0xff) << 24;
+    word |= (input[cur++] & 0xff) << 16;
+    word |= (input[cur++] & 0xff) << 8;
+    word |= (input[cur++] & 0xff);
+    output[cur_out++] = word;
+  }
+  // Fill the rest of the output with the remaining bytes or zeros if no more
+  // data is available.
+  while (cur_out < (out_offset + out_len)) {
+    var word = 0;
+    var bit_shift = (_BYTES_PER_WORD - 1) * _BITS_PER_BYTE;
+    while (cur < end) {
+      word |= (input[cur++] & 0xff) << bit_shift;
+      bit_shift -= _BITS_PER_BYTE;
+    }
+    output[cur_out++] = word;
+  }
+}
+
+List<int> _wordsToBytes(List<int> input) {

[Ivan Posva, 2012/04/24 09:23:53]

This should change to take an output target, as well as offsets and lengths for
both input and output.

+  var len = input.length;
+  var output = new List<int>(len * _BYTES_PER_WORD);
+  var cur = 0;
+  for (var word in input) {
+    output[cur++] = word >> 24;
+    output[cur++] = (word >> 16) & 0xff;
+    output[cur++] = (word >> 8) & 0xff;
+    output[cur++] = word & 0xff;
+  }
+  return output;
+}