diff options
| -rw-r--r-- | crypto/src/math/BigInteger.cs | 17 | ||||
| -rw-r--r-- | crypto/src/pqc/crypto/picnic/PicnicUtilities.cs | 35 | ||||
| -rw-r--r-- | crypto/src/util/Integers.cs | 21 | ||||
| -rw-r--r-- | crypto/test/src/util/utiltest/IntegersTest.cs | 33 |
4 files changed, 58 insertions, 48 deletions
diff --git a/crypto/src/math/BigInteger.cs b/crypto/src/math/BigInteger.cs index 5b2ea0d87..d84680de5 100644 --- a/crypto/src/math/BigInteger.cs +++ b/crypto/src/math/BigInteger.cs @@ -942,7 +942,7 @@ namespace Org.BouncyCastle.Math int sum = 0; for (int i = 0; i < magnitude.Length; ++i) { - sum += BitCnt(magnitude[i]); + sum += Integers.PopCount(magnitude[i]); } nBits = sum; } @@ -952,21 +952,6 @@ namespace Org.BouncyCastle.Math } } - internal static int BitCnt(uint u) - { -#if NETCOREAPP3_0_OR_GREATER - return BitOperations.PopCount(u); -#else - u = u - ((u >> 1) & 0x55555555); - u = (u & 0x33333333) + ((u >> 2) & 0x33333333); - u = (u + (u >> 4)) & 0x0f0f0f0f; - u += (u >> 8); - u += (u >> 16); - u &= 0x3f; - return (int)u; -#endif - } - private static int CalcBitLength(int sign, int indx, uint[] mag) { for (;;) diff --git a/crypto/src/pqc/crypto/picnic/PicnicUtilities.cs b/crypto/src/pqc/crypto/picnic/PicnicUtilities.cs index a2f1ca080..d77d7ce29 100644 --- a/crypto/src/pqc/crypto/picnic/PicnicUtilities.cs +++ b/crypto/src/pqc/crypto/picnic/PicnicUtilities.cs @@ -34,48 +34,19 @@ namespace Org.BouncyCastle.Pqc.Crypto.Picnic x ^= data[i]; } - return (int)Parity16(x); + return Integers.PopCount(x) & 1; } internal static uint Parity16(uint x) { -#if NETCOREAPP3_0_OR_GREATER - if (Popcnt.IsSupported) - { - return Popcnt.PopCount(x & 0xFFFF) & 1U; - } -#endif - - uint y = x ^ (x >> 1); - - y ^= (y >> 2); - y ^= (y >> 4); - y ^= (y >> 8); - return y & 1; + return (uint)(Integers.PopCount(x & 0xFFFF) & 1); } internal static uint Parity32(uint x) { -#if NETCOREAPP3_0_OR_GREATER - if (Popcnt.IsSupported) - { - return Popcnt.PopCount(x) & 1U; - } -#endif - - /* Compute parity of x using code from Section 5-2 of - * H.S. Warren, *Hacker's Delight*, Pearson Education, 2003. - * http://www.hackersdelight.org/hdcodetxt/parity.c.txt - */ - uint y = (x ^ (x >> 1)); - y ^= (y >> 2); - y ^= (y >> 4); - y ^= (y >> 8); - y ^= (y >> 16); - return (y & 1); + return (uint)(Integers.PopCount(x) & 1); } - /* Set a specific bit in a byte array to a given value */ internal static void SetBitInWordArray(uint[] array, int bitNumber, uint val) { diff --git a/crypto/src/util/Integers.cs b/crypto/src/util/Integers.cs index eff7056b6..87ba9cbb0 100644 --- a/crypto/src/util/Integers.cs +++ b/crypto/src/util/Integers.cs @@ -79,6 +79,27 @@ namespace Org.BouncyCastle.Utilities #endif } + public static int PopCount(int i) + { + return PopCount((uint)i); + } + + [CLSCompliant(false)] + public static int PopCount(uint u) + { +#if NETCOREAPP3_0_OR_GREATER + return BitOperations.PopCount(u); +#else + u -= (u >> 1) & 0x55555555; + u = (u & 0x33333333) + ((u >> 2) & 0x33333333); + u = (u + (u >> 4)) & 0x0f0f0f0f; + u += (u >> 8); + u += (u >> 16); + u &= 0x3f; + return (int)u; +#endif + } + public static int Reverse(int i) { return (int)Reverse((uint)i); diff --git a/crypto/test/src/util/utiltest/IntegersTest.cs b/crypto/test/src/util/utiltest/IntegersTest.cs index a661144db..91c0bf2b6 100644 --- a/crypto/test/src/util/utiltest/IntegersTest.cs +++ b/crypto/test/src/util/utiltest/IntegersTest.cs @@ -32,5 +32,38 @@ namespace Org.BouncyCastle.Utilities.UtilTests Assert.AreEqual(31, Integers.NumberOfTrailingZeros(int.MinValue)); Assert.AreEqual(32, Integers.NumberOfTrailingZeros(0)); } + + [Test] + public void TestPopCount() + { + Random random = new Random(); + + for (int pos = 0; pos <= 24; ++pos) + { + int seed = Integers.RotateLeft(random.Next(0xFFFFFF) << 8, pos); + ImplTestPopCountRange(seed, pos, 0xFF); + } + } + + private static void ImplTestPopCountRange(int seed, int pos, int count) + { + for (int i = 0; i < count; ++i) + { + int n = seed + (i << pos); + int expected = SimpleBitCount(n); + Assert.AreEqual(expected, Integers.PopCount(n)); + Assert.AreEqual(expected, Integers.PopCount((uint)n)); + } + } + + private static int SimpleBitCount(int n) + { + int count = 0; + for (int i = 0; i < 32; ++i) + { + count += (n >> i) & 1; + } + return count; + } } } |