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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System.Diagnostics;
using System.Runtime.CompilerServices;
namespace System.Buffers.Text
{
internal static partial class FormattingHelpers
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static int CountDigits(ulong value)
{
int digits = 1;
uint part;
if (value >= 10000000)
{
if (value >= 100000000000000)
{
part = (uint)(value / 100000000000000);
digits += 14;
}
else
{
part = (uint)(value / 10000000);
digits += 7;
}
}
else
{
part = (uint)value;
}
if (part < 10)
{
// no-op
}
else if (part < 100)
{
digits += 1;
}
else if (part < 1000)
{
digits += 2;
}
else if (part < 10000)
{
digits += 3;
}
else if (part < 100000)
{
digits += 4;
}
else if (part < 1000000)
{
digits += 5;
}
else
{
Debug.Assert(part < 10000000);
digits += 6;
}
return digits;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static int CountDigits(uint value)
{
int digits = 1;
if (value >= 100000)
{
value = value / 100000;
digits += 5;
}
if (value < 10)
{
// no-op
}
else if (value < 100)
{
digits += 1;
}
else if (value < 1000)
{
digits += 2;
}
else if (value < 10000)
{
digits += 3;
}
else
{
Debug.Assert(value < 100000);
digits += 4;
}
return digits;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static int CountHexDigits(ulong value)
{
// TODO: When x86 intrinsic support comes online, experiment with implementing this using lzcnt.
// return 16 - (int)((uint)Lzcnt.LeadingZeroCount(value | 1) >> 3);
int digits = 1;
if (value > 0xFFFFFFFF)
{
digits += 8;
value >>= 0x20;
}
if (value > 0xFFFF)
{
digits += 4;
value >>= 0x10;
}
if (value > 0xFF)
{
digits += 2;
value >>= 0x8;
}
if (value > 0xF)
digits++;
return digits;
}
// Counts the number of trailing '0' digits in a decimal number.
// e.g., value = 0 => retVal = 0, valueWithoutTrailingZeros = 0
// value = 1234 => retVal = 0, valueWithoutTrailingZeros = 1234
// value = 320900 => retVal = 2, valueWithoutTrailingZeros = 3209
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static int CountDecimalTrailingZeros(uint value, out uint valueWithoutTrailingZeros)
{
int zeroCount = 0;
if (value != 0)
{
while (true)
{
uint temp = value / 10;
if (value != (temp * 10))
{
break;
}
value = temp;
zeroCount++;
}
}
valueWithoutTrailingZeros = value;
return zeroCount;
}
}
}
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