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@jfd16
jfd16 committed Feb 9, 2021
1 parent 5657cfc commit 7b5eb62
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Showing 2 changed files with 75 additions and 83 deletions.
20 changes: 5 additions & 15 deletions src/libraries/System.Runtime.Numerics/src/System/Numerics/BigInteger.cs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -464,7 +464,7 @@ public BigInteger(ReadOnlySpan<byte> value, bool isUnsigned = false, bool isBigE
AssertValid();
}

private BigInteger(int n, uint[]? rgu)
internal BigInteger(int n, uint[]? rgu)
{
_sign = n;
_bits = rgu;
Expand Down Expand Up @@ -683,8 +683,7 @@ public static BigInteger Parse(string value, IFormatProvider? provider)

public static BigInteger Parse(string value, NumberStyles style, IFormatProvider? provider)
{
(int sign, uint[]? bits) = BigNumber.ParseBigInteger(value, style, NumberFormatInfo.GetInstance(provider));
return new BigInteger(sign, bits);
return BigNumber.ParseBigInteger(value, style, NumberFormatInfo.GetInstance(provider));
}

public static bool TryParse([NotNullWhen(true)] string? value, out BigInteger result)
Expand All @@ -694,17 +693,12 @@ public static bool TryParse([NotNullWhen(true)] string? value, out BigInteger re

public static bool TryParse([NotNullWhen(true)] string? value, NumberStyles style, IFormatProvider? provider, out BigInteger result)
{
bool success = BigNumber.TryParseBigInteger(
value, style, NumberFormatInfo.GetInstance(provider), out int sign, out uint[]? bits);

result = new BigInteger(sign, bits);
return success;
return BigNumber.TryParseBigInteger(value, style, NumberFormatInfo.GetInstance(provider), out result);
}

public static BigInteger Parse(ReadOnlySpan<char> value, NumberStyles style = NumberStyles.Integer, IFormatProvider? provider = null)
{
(int sign, uint[]? bits) = BigNumber.ParseBigInteger(value, style, NumberFormatInfo.GetInstance(provider));
return new BigInteger(sign, bits);
return BigNumber.ParseBigInteger(value, style, NumberFormatInfo.GetInstance(provider));
}

public static bool TryParse(ReadOnlySpan<char> value, out BigInteger result)
Expand All @@ -714,11 +708,7 @@ public static bool TryParse(ReadOnlySpan<char> value, out BigInteger result)

public static bool TryParse(ReadOnlySpan<char> value, NumberStyles style, IFormatProvider? provider, out BigInteger result)
{
bool success = BigNumber.TryParseBigInteger(
value, style, NumberFormatInfo.GetInstance(provider), out int sign, out uint[]? bits);

result = new BigInteger(sign, bits);
return success;
return BigNumber.TryParseBigInteger(value, style, NumberFormatInfo.GetInstance(provider), out result);
}

public static int Compare(BigInteger left, BigInteger right)
Expand Down
138 changes: 70 additions & 68 deletions src/libraries/System.Runtime.Numerics/src/System/Numerics/BigNumber.cs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -325,49 +325,48 @@ internal static bool TryValidateParseStyleInteger(NumberStyles style, [NotNullWh
return true;
}

internal static bool TryParseBigInteger(string? value, NumberStyles style, NumberFormatInfo info, out int sign, out uint[]? bits)
internal static bool TryParseBigInteger(string? value, NumberStyles style, NumberFormatInfo info, out BigInteger result)
{
if (value == null)
{
sign = 0;
bits = null;
result = default;
return false;
}

return TryParseBigInteger(value.AsSpan(), style, info, out sign, out bits);
return TryParseBigInteger(value.AsSpan(), style, info, out result);
}

internal static bool TryParseBigInteger(ReadOnlySpan<char> value, NumberStyles style, NumberFormatInfo info, out int sign, out uint[]? bits)
internal static bool TryParseBigInteger(ReadOnlySpan<char> value, NumberStyles style, NumberFormatInfo info, out BigInteger result)
{
sign = 0;
bits = null;

ArgumentException? e;
if (!TryValidateParseStyleInteger(style, out e))
throw e; // TryParse still throws ArgumentException on invalid NumberStyles

BigNumberBuffer bignumber = BigNumberBuffer.Create();
if (!FormatProvider.TryStringToBigInteger(value, style, info, bignumber.digits, out bignumber.precision, out bignumber.scale, out bignumber.sign))
{
result = default;
return false;
}

if ((style & NumberStyles.AllowHexSpecifier) != 0)
{
if (!HexNumberToBigInteger(ref bignumber, out sign, out bits))
if (!HexNumberToBigInteger(ref bignumber, out result))
{
return false;
}
}
else
{
if (!NumberToBigInteger(ref bignumber, out sign, out bits))
if (!NumberToBigInteger(ref bignumber, out result))
{
return false;
}
}
return true;
}

internal static (int sign, uint[]? bits) ParseBigInteger(string value, NumberStyles style, NumberFormatInfo info)
internal static BigInteger ParseBigInteger(string value, NumberStyles style, NumberFormatInfo info)
{
if (value == null)
{
Expand All @@ -377,41 +376,41 @@ internal static (int sign, uint[]? bits) ParseBigInteger(string value, NumberSty
return ParseBigInteger(value.AsSpan(), style, info);
}

internal static (int sign, uint[]? bits) ParseBigInteger(ReadOnlySpan<char> value, NumberStyles style, NumberFormatInfo info)
internal static BigInteger ParseBigInteger(ReadOnlySpan<char> value, NumberStyles style, NumberFormatInfo info)
{
ArgumentException? e;
if (!TryValidateParseStyleInteger(style, out e))
throw e;

if (!TryParseBigInteger(value, style, info, out int sign, out uint[]? bits))
if (!TryParseBigInteger(value, style, info, out BigInteger result))
{
throw new FormatException(SR.Overflow_ParseBigInteger);
}
return (sign, bits);
return result;
}

private static bool HexNumberToBigInteger(ref BigNumberBuffer number, out int sign, out uint[]? bits)
private static bool HexNumberToBigInteger(ref BigNumberBuffer number, out BigInteger result)
{
sign = 0;
bits = null;

if (number.digits == null || number.digits.Length == 0)
{
result = default;
return false;
}

const int DigitsPerBlock = 8;

int totalDigitCount = number.digits.Length - 1; // Ignore trailing '\0'
int blockCount, partialDigitCount;

if (totalDigitCount % DigitsPerBlock == 0)
if ((uint)totalDigitCount % DigitsPerBlock == 0)
{
blockCount = totalDigitCount / DigitsPerBlock;
partialDigitCount = 0;
}
else
{
blockCount = (totalDigitCount / DigitsPerBlock) + 1;
partialDigitCount = DigitsPerBlock - (totalDigitCount % DigitsPerBlock);
blockCount = Math.DivRem(totalDigitCount, DigitsPerBlock, out int mod) + 1;
partialDigitCount = DigitsPerBlock - mod;
}

bool isNegative = HexConverter.FromChar(number.digits[0]) >= 8;
Expand All @@ -427,22 +426,45 @@ private static bool HexNumberToBigInteger(ref BigNumberBuffer number, out int si

try
{
foreach (ReadOnlyMemory<char> digitsChunk in number.digits.GetChunks())
ProcessChunk(digitsChunk.Span, bitsBuffer);
foreach (ReadOnlyMemory<char> digitsChunkMem in number.digits.GetChunks())
{
ReadOnlySpan<char> chunkDigits = digitsChunkMem.Span;
for (int i = 0; i < chunkDigits.Length; i++)
{
char digitChar = chunkDigits[i];
if (digitChar == '\0')
break;

int hexValue = HexConverter.FromChar(digitChar);
Debug.Assert(hexValue != 0xFF);

partialValue = (partialValue << 4) | (uint)hexValue;
partialDigitCount++;

if (partialDigitCount == DigitsPerBlock)
{
bitsBuffer[bitsBufferPos] = (int)partialValue;
bitsBufferPos--;
partialValue = 0;
partialDigitCount = 0;
}
}
}

Debug.Assert(partialDigitCount == 0 && bitsBufferPos == -1);

// BigInteger requires leading zero blocks to be truncated.
int blockCountNoLeadingZeros = blockCount;
while (blockCountNoLeadingZeros > 0 && bitsBuffer[blockCountNoLeadingZeros - 1] == 0)
blockCountNoLeadingZeros--;
bitsBuffer = bitsBuffer.TrimEnd(0);

if (blockCountNoLeadingZeros == 0)
int sign;
uint[]? bits;

if (bitsBuffer.IsEmpty)
{
sign = 0;
bits = null;
}
else if (blockCountNoLeadingZeros == 1)
else if (bitsBuffer.Length == 1)
{
sign = bitsBuffer[0];
bits = null;
Expand All @@ -456,50 +478,24 @@ private static bool HexNumberToBigInteger(ref BigNumberBuffer number, out int si
else
{
sign = isNegative ? -1 : 1;
bits = MemoryMarshal.Cast<int, uint>(bitsBuffer).Slice(0, blockCountNoLeadingZeros).ToArray();
bits = MemoryMarshal.Cast<int, uint>(bitsBuffer).ToArray();

if (isNegative)
NumericsHelpers.DangerousMakeTwosComplement(bits);
}

result = new BigInteger(sign, bits);
return true;
}
finally
{
if (arrayFromPool != null)
ArrayPool<int>.Shared.Return(arrayFromPool);
}

void ProcessChunk(ReadOnlySpan<char> chunkDigits, Span<int> _bitsBuffer)
{
for (int i = 0; i < chunkDigits.Length; i++)
{
char digitChar = chunkDigits[i];
if (digitChar == '\0')
return;

int hexValue = HexConverter.FromChar(digitChar);
Debug.Assert(hexValue != 0xFF);

partialValue = (partialValue << 4) | (uint)hexValue;
partialDigitCount++;

if (partialDigitCount == DigitsPerBlock)
{
_bitsBuffer[bitsBufferPos] = (int)partialValue;
bitsBufferPos--;
partialValue = 0;
partialDigitCount = 0;
}
}
}
}

private static bool NumberToBigInteger(ref BigNumberBuffer number, out int sign, out uint[]? bits)
private static bool NumberToBigInteger(ref BigNumberBuffer number, out BigInteger result)
{
sign = 0;
bits = null;

Span<int> stackBuffer = stackalloc int[BigInteger.StackallocUInt32Limit];
Span<int> currentBuffer = stackBuffer;
int currentBufferSize = 0;
Expand All @@ -517,9 +513,11 @@ private static bool NumberToBigInteger(ref BigNumberBuffer number, out int sign,
{
foreach (ReadOnlyMemory<char> digitsChunk in number.digits.GetChunks())
{
bool isValid = ProcessChunk(digitsChunk.Span, ref currentBuffer);
if (!isValid)
if (!ProcessChunk(digitsChunk.Span, ref currentBuffer))
{
result = default;
return false;
}
}

if (partialDigitCount > 0)
Expand All @@ -536,12 +534,15 @@ private static bool NumberToBigInteger(ref BigNumberBuffer number, out int sign,
if (trailingZeroCount > 0)
MultiplyAdd(ref currentBuffer, s_uint32PowersOfTen[trailingZeroCount], 0);

int sign;
uint[]? bits;

if (currentBufferSize == 0)
{
sign = 0;
bits = null;
}
else if (currentBufferSize == 1 && currentBuffer[0] <= int.MaxValue)
else if (currentBufferSize == 1 && (uint)currentBuffer[0] <= int.MaxValue)
{
sign = number.sign ? -currentBuffer[0] : currentBuffer[0];
bits = null;
Expand All @@ -552,6 +553,7 @@ private static bool NumberToBigInteger(ref BigNumberBuffer number, out int sign,
bits = MemoryMarshal.Cast<int, uint>(currentBuffer).Slice(0, currentBufferSize).ToArray();
}

result = new BigInteger(sign, bits);
return true;
}
finally
Expand All @@ -560,7 +562,7 @@ private static bool NumberToBigInteger(ref BigNumberBuffer number, out int sign,
ArrayPool<int>.Shared.Return(arrayFromPool);
}

bool ProcessChunk(ReadOnlySpan<char> chunkDigits, ref Span<int> _currentBuffer)
bool ProcessChunk(ReadOnlySpan<char> chunkDigits, ref Span<int> currentBuffer)
{
int remainingIntDigitCount = Math.Max(numberScale - totalDigitCount, 0);
ReadOnlySpan<char> intDigitsSpan = chunkDigits.Slice(0, Math.Min(remainingIntDigitCount, chunkDigits.Length));
Expand All @@ -578,7 +580,7 @@ bool ProcessChunk(ReadOnlySpan<char> chunkDigits, ref Span<int> _currentBuffer)
// Update the buffer when enough partial digits have been accumulated.
if (partialDigitCount == MaxPartialDigits)
{
MultiplyAdd(ref _currentBuffer, TenPowMaxPartial, partialValue);
MultiplyAdd(ref currentBuffer, TenPowMaxPartial, partialValue);
partialValue = 0;
partialDigitCount = 0;
}
Expand All @@ -598,9 +600,9 @@ bool ProcessChunk(ReadOnlySpan<char> chunkDigits, ref Span<int> _currentBuffer)
return true;
}

void MultiplyAdd(ref Span<int> _currentBuffer, uint multiplier, uint addValue)
void MultiplyAdd(ref Span<int> currentBuffer, uint multiplier, uint addValue)
{
Span<int> curBits = _currentBuffer.Slice(0, currentBufferSize);
Span<int> curBits = currentBuffer.Slice(0, currentBufferSize);
uint carry = addValue;

for (int i = 0; i < curBits.Length; i++)
Expand All @@ -613,19 +615,19 @@ void MultiplyAdd(ref Span<int> _currentBuffer, uint multiplier, uint addValue)
if (carry == 0)
return;

if (currentBufferSize == _currentBuffer.Length)
if (currentBufferSize == currentBuffer.Length)
{
int[]? arrayToReturn = arrayFromPool;

arrayFromPool = ArrayPool<int>.Shared.Rent(checked(currentBufferSize * 2));
_currentBuffer.CopyTo(arrayFromPool);
_currentBuffer = arrayFromPool;
currentBuffer.CopyTo(arrayFromPool);
currentBuffer = arrayFromPool;

if (arrayToReturn != null)
ArrayPool<int>.Shared.Return(arrayToReturn);
}

_currentBuffer[currentBufferSize] = (int)carry;
currentBuffer[currentBufferSize] = (int)carry;
currentBufferSize++;
}
}
Expand Down

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