OLD | NEW |
1 // Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file |
2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
4 | 4 |
5 library crypto.utils; | 5 library crypto.utils; |
6 | 6 |
7 // Constants. | 7 /// A bitmask that limits an integer to 8 bits. |
8 const MASK_8 = 0xff; | 8 const MASK_8 = 0xff; |
| 9 |
| 10 /// A bitmask that limits an integer to 32 bits. |
9 const MASK_32 = 0xffffffff; | 11 const MASK_32 = 0xffffffff; |
| 12 |
| 13 /// The number of bits in a byte. |
10 const BITS_PER_BYTE = 8; | 14 const BITS_PER_BYTE = 8; |
| 15 |
| 16 /// The number of bytes in a 32-bit word. |
11 const BYTES_PER_WORD = 4; | 17 const BYTES_PER_WORD = 4; |
12 | 18 |
13 // Helper methods. | 19 /// Adds [x] and [y] with 32-bit overflow semantics. |
14 int add32(x, y) => (x + y) & MASK_32; | 20 int add32(x, y) => (x + y) & MASK_32; |
15 | 21 |
16 int roundUp(val, n) => (val + n - 1) & -n; | 22 /// Bitwise rotates [val] to the left by [shift], obeying 32-bit overflow |
17 | 23 /// semantics. |
18 // Helper functions used by more than one hasher. | |
19 | |
20 // Rotate left limiting to unsigned 32-bit values. | |
21 int rotl32(int val, int shift) { | 24 int rotl32(int val, int shift) { |
22 var mod_shift = shift & 31; | 25 var mod_shift = shift & 31; |
23 return ((val << mod_shift) & MASK_32) | | 26 return ((val << mod_shift) & MASK_32) | |
24 ((val & MASK_32) >> (32 - mod_shift)); | 27 ((val & MASK_32) >> (32 - mod_shift)); |
25 } | 28 } |
OLD | NEW |