diff options
Diffstat (limited to 'crypto/src/math/BigInteger.cs')
| -rw-r--r-- | crypto/src/math/BigInteger.cs | 189 |
1 files changed, 174 insertions, 15 deletions
diff --git a/crypto/src/math/BigInteger.cs b/crypto/src/math/BigInteger.cs index a98955779..7da886c4f 100644 --- a/crypto/src/math/BigInteger.cs +++ b/crypto/src/math/BigInteger.cs @@ -475,8 +475,15 @@ namespace Org.BouncyCastle.Math } public BigInteger(byte[] bytes) - : this(bytes, 0, bytes.Length) { + this.magnitude = InitBE(bytes, 0, bytes.Length, out this.sign); + } + + public BigInteger(byte[] bytes, bool bigEndian) + { + this.magnitude = bigEndian + ? InitBE(bytes, 0, bytes.Length, out this.sign) + : InitLE(bytes, 0, bytes.Length, out this.sign); } public BigInteger(byte[] bytes, int offset, int length) @@ -484,16 +491,30 @@ namespace Org.BouncyCastle.Math if (length == 0) throw new FormatException("Zero length BigInteger"); - // TODO Move this processing into MakeMagnitude (provide sign argument) + this.magnitude = InitBE(bytes, offset, length, out this.sign); + } + + public BigInteger(byte[] bytes, int offset, int length, bool bigEndian) + { + if (length <= 0) + throw new FormatException("Zero length BigInteger"); + + this.magnitude = bigEndian + ? InitBE(bytes, offset, length, out this.sign) + : InitLE(bytes, offset, length, out this.sign); + } + + private static uint[] InitBE(byte[] bytes, int offset, int length, out int sign) + { + // TODO Move this processing into MakeMagnitudeBE (provide sign argument) if ((sbyte)bytes[offset] >= 0) { - // strip leading zero bytes and return magnitude bytes - this.magnitude = MakeMagnitudeBE(bytes, offset, length); - this.sign = this.magnitude.Length > 0 ? 1 : 0; - return; + uint[] magnitude = MakeMagnitudeBE(bytes, offset, length); + sign = magnitude.Length > 0 ? 1 : 0; + return magnitude; } - this.sign = -1; + sign = -1; int end = offset + length; @@ -504,10 +525,7 @@ namespace Org.BouncyCastle.Math } if (iBval >= end) - { - this.magnitude = One.magnitude; - return; - } + return One.magnitude; int numBytes = end - iBval; @@ -534,7 +552,56 @@ namespace Org.BouncyCastle.Math inverse[index]++; - this.magnitude = MakeMagnitudeBE(inverse); + return MakeMagnitudeBE(inverse); + } + + private static uint[] InitLE(byte[] bytes, int offset, int length, out int sign) + { + int end = offset + length; + + // TODO Move this processing into MakeMagnitudeLE (provide sign argument) + if ((sbyte)bytes[end - 1] >= 0) + { + uint[] magnitude = MakeMagnitudeLE(bytes, offset, length); + sign = magnitude.Length > 0 ? 1 : 0; + return magnitude; + } + + sign = -1; + + // strip leading sign bytes + int last = length; + while (--last >= 0 && bytes[offset + last] == byte.MaxValue) + { + } + + if (last < 0) + return One.magnitude; + + int numBytes = last + 1; + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + Span<byte> inverse = numBytes <= 512 + ? stackalloc byte[numBytes] + : new byte[numBytes]; +#else + byte[] inverse = new byte[numBytes]; +#endif + + for (int i = 0; i < numBytes; ++i) + { + inverse[i] = (byte)~bytes[offset + i]; + } + + int index = 0; + while (inverse[index] == byte.MaxValue) + { + inverse[index++] = byte.MinValue; + } + + inverse[index]++; + + return MakeMagnitudeLE(inverse); } private static uint[] MakeMagnitudeBE(byte[] bytes) @@ -600,12 +667,95 @@ namespace Org.BouncyCastle.Math } #endif + private static uint[] MakeMagnitudeLE(byte[] bytes) + { + return MakeMagnitudeLE(bytes, 0, bytes.Length); + } + + private static uint[] MakeMagnitudeLE(byte[] bytes, int offset, int length) + { +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + return MakeMagnitudeLE(bytes.AsSpan(offset, length)); +#else + // strip leading zeros + int last = length; + while (--last >= 0 && bytes[offset + last] == 0) + { + } + + if (last < 0) + return ZeroMagnitude; + + int nInts = (last + BytesPerInt) / BytesPerInt; + Debug.Assert(nInts > 0); + + uint[] magnitude = new uint[nInts]; + + int partial = last % BytesPerInt; + int first = partial + 1; + int pos = offset + last - partial; + + magnitude[0] = Pack.LE_To_UInt32_Low(bytes, pos, first); + for (int i = 1; i < nInts; ++i) + { + pos -= BytesPerInt; + magnitude[i] = Pack.LE_To_UInt32(bytes, pos); + } + Debug.Assert(pos == offset); + + return magnitude; +#endif + } + +#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER + private static uint[] MakeMagnitudeLE(ReadOnlySpan<byte> bytes) + { + // strip leading zeros + int last = bytes.Length; + while (--last >= 0 && bytes[last] == 0) + { + } + + if (last < 0) + return ZeroMagnitude; + + int nInts = (last + BytesPerInt) / BytesPerInt; + Debug.Assert(nInts > 0); + + uint[] magnitude = new uint[nInts]; + + int partial = last % BytesPerInt; + int first = partial + 1; + int pos = last - partial; + + magnitude[0] = Pack.LE_To_UInt32_Low(bytes.Slice(pos, first)); + for (int i = 1; i < nInts; ++i) + { + pos -= BytesPerInt; + magnitude[i] = Pack.LE_To_UInt32(bytes, pos); + } + Debug.Assert(pos == 0); + + return magnitude; + } +#endif + public BigInteger(int sign, byte[] bytes) - : this(sign, bytes, 0, bytes.Length) + : this(sign, bytes, 0, bytes.Length, true) + { + } + + public BigInteger(int sign, byte[] bytes, bool bigEndian) + : this(sign, bytes, 0, bytes.Length, bigEndian) { } public BigInteger(int sign, byte[] bytes, int offset, int length) + : this(sign, bytes, offset, length, true) + { + } + + public BigInteger(int sign, byte[] bytes, int offset, int length, bool bigEndian) { if (sign < -1 || sign > 1) throw new FormatException("Invalid sign value"); @@ -618,13 +768,20 @@ namespace Org.BouncyCastle.Math else { // copy bytes - this.magnitude = MakeMagnitudeBE(bytes, offset, length); + this.magnitude = bigEndian + ? MakeMagnitudeBE(bytes, offset, length) + : MakeMagnitudeLE(bytes, offset, length); this.sign = this.magnitude.Length < 1 ? 0 : sign; } } #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER public BigInteger(int sign, ReadOnlySpan<byte> bytes) + : this(sign, bytes, true) + { + } + + public BigInteger(int sign, ReadOnlySpan<byte> bytes, bool bigEndian) { if (sign < -1 || sign > 1) throw new FormatException("Invalid sign value"); @@ -637,7 +794,9 @@ namespace Org.BouncyCastle.Math else { // copy bytes - this.magnitude = MakeMagnitudeBE(bytes); + this.magnitude = bigEndian + ? MakeMagnitudeBE(bytes) + : MakeMagnitudeLE(bytes); this.sign = this.magnitude.Length < 1 ? 0 : sign; } } |