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Diffstat (limited to 'crypto/src/util/Integers.cs')
| -rw-r--r-- | crypto/src/util/Integers.cs | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/crypto/src/util/Integers.cs b/crypto/src/util/Integers.cs index e746b0ef4..bd05a053e 100644 --- a/crypto/src/util/Integers.cs +++ b/crypto/src/util/Integers.cs @@ -4,6 +4,21 @@ namespace Org.BouncyCastle.Utilities { public abstract class Integers { + public static int NumberOfLeadingZeros(int i) + { + if (i <= 0) + return (~i >> (31 - 5)) & (1 << 5); + + uint u = (uint)i; + int n = 1; + if (0 == (u >> 16)) { n += 16; u <<= 16; } + if (0 == (u >> 24)) { n += 8; u <<= 8; } + if (0 == (u >> 28)) { n += 4; u <<= 4; } + if (0 == (u >> 30)) { n += 2; u <<= 2; } + n -= (int)(u >> 31); + return n; + } + public static int RotateLeft(int i, int distance) { return (i << distance) ^ (int)((uint)i >> -distance); |