Nb1X/DepotDownloader
1
0 Fork 0
mirror of https://github.com/SteamRE/DepotDownloader.git synced 2026-10-19 15:51:50 +00:00
Code Issues Packages Projects Releases Wiki Activity

Optimize calculating adler hashes to not allocate entire chunk in memory

Browse Source
This commit is contained in:
Pavel Djundik committed 2024-08-13 17:48:06 +03:00
1 parent e7e2299b70
commit 294dbff40a
2 files changed
+21 -35
Download Patch File Download Diff File Expand all files Collapse all files

No files matched your search

DepotDownloader/ContentDownloader.cs
+12 -4
View File
@@ -1059,10 +1059,18 @@ namespace DepotDownloader
{
fsOld.Seek((long)match.OldChunk.Offset, SeekOrigin.Begin);
var tmp = new byte[match.OldChunk.UncompressedLength];
fsOld.Read(tmp, 0, tmp.Length);
uint a = 0, b = 0;
var adler = Util.AdlerHash(tmp);
for (var i = 0; i < match.OldChunk.UncompressedLength; i++)
{
var c = (uint)fsOld.ReadByte();
// adler hash
a = (a + c) % 65521;
b = (b + a) % 65521;
}
var adler = BitConverter.GetBytes(a | (b << 16));
if (!adler.SequenceEqual(match.OldChunk.Checksum))
{
neededChunks.Add(match.NewChunk);
@@ -1191,7 +1199,7 @@ namespace DepotDownloader
var depot = depotFilesData.depotDownloadInfo;
var depotDownloadCounter = depotFilesData.depotCounter;
var chunkID = Util.EncodeHexString(chunk.ChunkID);
var chunkID = Convert.ToHexString(chunk.ChunkID).ToLowerInvariant();
var data = new DepotManifest.ChunkData
{
DepotDownloader/Util.cs
+9 -31
View File
@@ -78,26 +78,23 @@ namespace DepotDownloader
public static List<ProtoManifest.ChunkData> ValidateSteam3FileChecksums(FileStream fs, ProtoManifest.ChunkData[] chunkdata)
{
var neededChunks = new List<ProtoManifest.ChunkData>();
int read;
foreach (var data in chunkdata)
{
var chunk = new byte[data.UncompressedLength];
fs.Seek((long)data.Offset, SeekOrigin.Begin);
read = fs.Read(chunk, 0, (int)data.UncompressedLength);
byte[] tempchunk;
if (read < data.UncompressedLength)
uint a = 0, b = 0;
for (var i = 0; i < data.UncompressedLength; i++)
{
tempchunk = new byte[read];
Array.Copy(chunk, 0, tempchunk, 0, read);
}
else
{
tempchunk = chunk;
var c = (uint)fs.ReadByte();
// adler hash
a = (a + c) % 65521;
b = (b + a) % 65521;
}
var adler = AdlerHash(tempchunk);
var adler = BitConverter.GetBytes(a | (b << 16));
if (!adler.SequenceEqual(data.Checksum))
{
neededChunks.Add(data);
@@ -107,18 +104,6 @@ namespace DepotDownloader
return neededChunks;
}
public static byte[] AdlerHash(byte[] input)
{
uint a = 0, b = 0;
for (var i = 0; i < input.Length; i++)
{
a = (a + input[i]) % 65521;
b = (b + a) % 65521;
}
return BitConverter.GetBytes(a | (b << 16));
}
public static byte[] DecodeHexString(string hex)
{
if (hex == null)
@@ -133,13 +118,6 @@ namespace DepotDownloader
return bytes;
}
public static string EncodeHexString(byte[] input)
{
return input.Aggregate(new StringBuilder(),
(sb, v) => sb.Append(v.ToString("x2"))
).ToString();
}
/// <summary>
/// Decrypts using AES/ECB/PKCS7
/// </summary>