# < Summary

Information

Class: | Renci.SshNet.Security.Org.BouncyCastle.Math.EC.Multiplier.FixedPointUtilities
Assembly: | Renci.SshNet
File(s): | \home\appveyor\projects\ssh-net\src\Renci.SshNet\Security\BouncyCastle\math\ec\multiplier\FixedPointUtilities.cs

Line coverage
94%

Covered lines: | 53
Uncovered lines: | 3
Coverable lines: | 56
Total lines: | 95
Line coverage: | 94.6%

Branch coverage
83%

Covered branches: | 15
Total branches: | 18
Branch coverage: | 83.3%

Method coverage

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# Metrics

Method | Branch coverage | Cyclomatic complexity | Line coverage
--- | --- | --- | ---
.cctor() | 100% | 1 | 100%
GetCombSize(...) | 50% | 2 | 100%
GetFixedPointPreCompInfo(...) | 100% | 1 | 0%
Precompute(...) | 100% | 1 | 100%
.ctor(...) | 100% | 1 | 100%
Precompute(...) | 91.66% | 12 | 100%
CheckExisting(...) | 100% | 2 | 100%
CheckTable(...) | 50% | 2 | 100%

# File(s)

## \home\appveyor\projects\ssh-net\src\Renci.SshNet\Security\BouncyCastle\math\ec\multiplier\FixedPointUtilities.cs

| # | Line |  | Line coverage
--- | --- | --- | --- | ---
|  | `1` |  | `using System;`
|  | `2` |  | ``
|  | `3` |  | `namespace Renci.SshNet.Security.Org.BouncyCastle.Math.EC.Multiplier`
|  | `4` |  | `{`
|  | `5` |  | `internal class FixedPointUtilities`
|  | `6` |  | `{`
| 1 | `7` |  | `public static readonly string PRECOMP_NAME = "bc_fixed_point";`
|  | `8` |  | ``
|  | `9` |  | `public static int GetCombSize(ECCurve c)`
| 18 | `10` |  | `{`
| 18 | `11` |  | `BigInteger order = c.Order;`
| 18 | `12` |  | `return order == null ? c.FieldSize + 1 : order.BitLength;`
| 18 | `13` |  | `}`
|  | `14` |  | ``
|  | `15` |  | `public static FixedPointPreCompInfo GetFixedPointPreCompInfo(PreCompInfo preCompInfo)`
| 0 | `16` |  | `{`
| 0 | `17` |  | `return preCompInfo as FixedPointPreCompInfo;`
| 0 | `18` |  | `}`
|  | `19` |  | ``
|  | `20` |  | `public static FixedPointPreCompInfo Precompute(ECPoint p)`
| 9 | `21` |  | `{`
| 9 | `22` |  | `return (FixedPointPreCompInfo)p.Curve.Precompute(p, PRECOMP_NAME, new FixedPointCallback(p));`
| 9 | `23` |  | `}`
|  | `24` |  | ``
|  | `25` |  | `private class FixedPointCallback`
|  | `26` |  | `: IPreCompCallback`
|  | `27` |  | `{`
|  | `28` |  | `private readonly ECPoint m_p;`
|  | `29` |  | ``
| 9 | `30` |  | `internal FixedPointCallback(ECPoint p)`
| 9 | `31` |  | `{`
| 9 | `32` |  | `this.m_p = p;`
| 9 | `33` |  | `}`
|  | `34` |  | ``
|  | `35` |  | `public PreCompInfo Precompute(PreCompInfo existing)`
| 9 | `36` |  | `{`
| 9 | `37` |  | `FixedPointPreCompInfo existingFP = (existing is FixedPointPreCompInfo) ? (FixedPointPreCompInfo)existing`
|  | `38` |  | ``
| 9 | `39` |  | `ECCurve c = m_p.Curve;`
| 9 | `40` |  | `int bits = FixedPointUtilities.GetCombSize(c);`
| 9 | `41` |  | `int minWidth = bits > 250 ? 6 : 5;`
| 9 | `42` |  | `int n = 1 << minWidth;`
|  | `43` |  | ``
| 9 | `44` |  | `if (CheckExisting(existingFP, n))`
| 6 | `45` |  | `return existingFP;`
|  | `46` |  | ``
| 3 | `47` |  | `int d = (bits + minWidth - 1) / minWidth;`
|  | `48` |  | ``
| 3 | `49` |  | `ECPoint[] pow2Table = new ECPoint[minWidth + 1];`
| 3 | `50` |  | `pow2Table[0] = m_p;`
| 36 | `51` |  | `for (int i = 1; i < minWidth; ++i)`
| 15 | `52` |  | `{`
| 15 | `53` |  | `pow2Table[i] = pow2Table[i - 1].TimesPow2(d);`
| 15 | `54` |  | `}`
|  | `55` |  | ``
|  | `56` |  | `// This will be the 'offset' value`
| 3 | `57` |  | `pow2Table[minWidth] = pow2Table[0].Subtract(pow2Table[1]);`
|  | `58` |  | ``
| 3 | `59` |  | `c.NormalizeAll(pow2Table);`
|  | `60` |  | ``
| 3 | `61` |  | `ECPoint[] lookupTable = new ECPoint[n];`
| 3 | `62` |  | `lookupTable[0] = pow2Table[0];`
|  | `63` |  | ``
| 42 | `64` |  | `for (int bit = minWidth - 1; bit >= 0; --bit)`
| 18 | `65` |  | `{`
| 18 | `66` |  | `ECPoint pow2 = pow2Table[bit];`
|  | `67` |  | ``
| 18 | `68` |  | `int step = 1 << bit;`
| 414 | `69` |  | `for (int i = step; i < n; i += (step << 1))`
| 189 | `70` |  | `{`
| 189 | `71` |  | `lookupTable[i] = lookupTable[i - step].Add(pow2);`
| 189 | `72` |  | `}`
| 18 | `73` |  | `}`
|  | `74` |  | ``
| 3 | `75` |  | `c.NormalizeAll(lookupTable);`
|  | `76` |  | ``
| 3 | `77` |  | `FixedPointPreCompInfo result = new FixedPointPreCompInfo();`
| 3 | `78` |  | `result.LookupTable = c.CreateCacheSafeLookupTable(lookupTable, 0, lookupTable.Length);`
| 3 | `79` |  | `result.Offset = pow2Table[minWidth];`
| 3 | `80` |  | `result.Width = minWidth;`
| 3 | `81` |  | `return result;`
| 9 | `82` |  | `}`
|  | `83` |  | ``
|  | `84` |  | `private bool CheckExisting(FixedPointPreCompInfo existingFP, int n)`
| 9 | `85` |  | `{`
| 9 | `86` |  | `return existingFP != null && CheckTable(existingFP.LookupTable, n);`
| 9 | `87` |  | `}`
|  | `88` |  | ``
|  | `89` |  | `private bool CheckTable(ECLookupTable table, int n)`
| 6 | `90` |  | `{`
| 6 | `91` |  | `return table != null && table.Size >= n;`
| 6 | `92` |  | `}`
|  | `93` |  | `}`
|  | `94` |  | `}`
|  | `95` |  | `}`

# Methods/Properties

.cctor()
GetCombSize(Renci.SshNet.Security.Org.BouncyCastle.Math.EC.ECCurve)
GetFixedPointPreCompInfo(Renci.SshNet.Security.Org.BouncyCastle.Math.EC.Multiplier.PreCompInfo)
Precompute(Renci.SshNet.Security.Org.BouncyCastle.Math.EC.ECPoint)
.ctor(Renci.SshNet.Security.Org.BouncyCastle.Math.EC.ECPoint)
Precompute(Renci.SshNet.Security.Org.BouncyCastle.Math.EC.Multiplier.PreCompInfo)
CheckExisting(Renci.SshNet.Security.Org.BouncyCastle.Math.EC.Multiplier.FixedPointPreCompInfo,System.Int32)
CheckTable(Renci.SshNet.Security.Org.BouncyCastle.Math.EC.ECLookupTable,System.Int32)