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alignment

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This commit is contained in:
ahmed
2026-04-09 14:03:04 +03:00
parent e0eaa450ee
commit 15479288cc
11 changed files with 796 additions and 2122 deletions
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Libraries/Esiur/Data/Gvwie/GroupUInt64Codec.cs
+111 -47
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@@ -1,25 +1,24 @@
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
namespace Esiur.Data.Gvwie;
using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
public static class GroupUInt64Codec
{
// ----------------- Encoder -----------------
public static byte[] Encode(IList<ulong> values)
{
if (values is null) throw new ArgumentNullException(nameof(values));
// Header layout:
// 1 | cccc | www
//
// MSB = 1 => grouped form
// cccc = 0..14 => short count = cccc + 1 (1..15)
// cccc = 15 => extended count, followed by varint(count - 16)
// www = 0..7 => width = www + 1 (1..8)
//
// MSB = 0 => literal fast path for values in 7 bits
// ----------------- Encoder -----------------
public static byte[] Encode(IList<ulong> values, bool aligned = false)
{
var dst = new List<byte>(values.Count * 2);
int i = 0;
@@ -27,34 +26,56 @@ public static class GroupUInt64Codec
{
ulong v = values[i];
// Fast path: single byte for 0..127
if (v <= 0x7FUL)
// Fast path: single byte (MSB=0) when value fits in 7 bits
if (v <= 0x7Ful)
{
dst.Add((byte)v); // MSB = 0 implicitly
dst.Add((byte)v);
i++;
continue;
}
// Group path: up to 16 items sharing max width (1..8 bytes)
int start = i;
int width = WidthFromValue(v, aligned);
int count = 1;
int width = WidthFromUnsigned(v);
while (count < 16 && (i + count) < values.Count)
// Build a run of same-width non-literal values
while ((i + count) < values.Count)
{
ulong v2 = values[i + count];
int w2 = WidthFromUnsigned(v2);
if (w2 > width) width = w2;
// Do not absorb literal-fast-path values into groups
if (v2 <= 0x7Ful)
break;
int w2 = WidthFromValue(v2, aligned);
if (w2 != width)
break;
count++;
}
// Header: 1 | (count-1)[4b] | (width-1)[3b]
byte header = 0x80;
header |= (byte)(((count - 1) & 0xF) << 3);
header |= (byte)((width - 1) & 0x7);
dst.Add(header);
if (count <= 15)
{
// Short group:
// Header: 1 | (count-1)[4 bits] | (width-1)[3 bits]
byte header = 0x80;
header |= (byte)(((count - 1) & 0x0F) << 3);
header |= (byte)((width - 1) & 0x07);
dst.Add(header);
}
else
{
// Extended group:
// Header: 1 | 1111 | (width-1)[3 bits]
// Followed by varint(count - 16)
byte header = 0x80;
header |= 0x78; // count bits = 1111
header |= (byte)((width - 1) & 0x07);
dst.Add(header);
WriteVarUInt32(dst, checked((uint)(count - 16)));
}
// Payload
// Payload: 'count' values, LE, 'width' bytes each
for (int k = 0; k < count; k++)
WriteLE(dst, values[start + k], width);
@@ -76,21 +97,29 @@ public static class GroupUInt64Codec
if ((h & 0x80) == 0)
{
// Fast path byte (0..127)
result.Add(h);
// Fast path: literal 7-bit unsigned value
result.Add((ulong)(h & 0x7F));
continue;
}
int count = ((h >> 3) & 0xF) + 1; // 1..16
int width = (h & 0x7) + 1; // 1..8
int countField = (h >> 3) & 0x0F;
int width = (h & 0x07) + 1; // 1..8
if (width < 1 || width > 8)
throw new NotSupportedException($"Invalid width {width} in header.");
int count;
if (countField == 15)
{
uint extra = ReadVarUInt32(src, ref pos);
count = checked(16 + (int)extra);
}
else
{
count = countField + 1;
}
for (int j = 0; j < count; j++)
{
ulong val = ReadLE(src, ref pos, width);
result.Add(val);
ulong raw = ReadLE(src, ref pos, width);
result.Add(raw);
}
}
@@ -98,16 +127,17 @@ public static class GroupUInt64Codec
}
// ----------------- Helpers -----------------
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static int WidthFromUnsigned(ulong v)
private static int WidthFromValue(ulong v, bool aligned = false)
{
if (v <= 0xFFUL) return 1;
if (v <= 0xFFFFUL) return 2;
if (v <= 0xFFFFFFUL) return 3;
if (v <= 0xFFFFFFFFUL) return 4;
if (v <= 0xFFFFFFFFFFUL) return 5;
if (v <= 0xFFFFFFFFFFFFUL) return 6;
if (v <= 0xFFFFFFFFFFFFFFUL) return 7;
if (v <= 0xFFul) return 1;
if (v <= 0xFFFFul) return 2;
if (v <= 0xFFFFFFul) return aligned ? 4 : 3;
if (v <= 0xFFFFFFFFul) return 4;
if (v <= 0xFFFFFFFFFFul) return aligned ? 8: 5;
if (v <= 0xFFFFFFFFFFFFul) return aligned ? 8: 6;
if (v <= 0xFFFFFFFFFFFFFFul) return aligned ? 8 : 7;
return 8;
}
@@ -121,13 +151,47 @@ public static class GroupUInt64Codec
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static ulong ReadLE(ReadOnlySpan<byte> src, ref int pos, int width)
{
if (pos + width > src.Length)
throw new ArgumentException("Buffer underflow while reading payload.");
if ((uint)(pos + width) > (uint)src.Length)
throw new ArgumentException("Buffer underflow while reading group payload.");
ulong v = 0;
for (int i = 0; i < width; i++)
v |= (ulong)src[pos++] << (8 * i);
return v;
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static void WriteVarUInt32(List<byte> dst, uint value)
{
while (value >= 0x80)
{
dst.Add((byte)((value & 0x7F) | 0x80));
value >>= 7;
}
dst.Add((byte)value);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static uint ReadVarUInt32(ReadOnlySpan<byte> src, ref int pos)
{
uint result = 0;
int shift = 0;
while (true)
{
if (pos >= src.Length)
throw new ArgumentException("Buffer underflow while reading varint.");
byte b = src[pos++];
result |= (uint)(b & 0x7F) << shift;
if ((b & 0x80) == 0)
return result;
shift += 7;
if (shift >= 35)
throw new ArgumentException("Varint is too long for UInt32.");
}
}
}