/// <summary>
/// 验证并初始化补丁解压流。
/// </summary>
public void OpenDecompress()
{
this.patchBlock = TrySplit(this.patchFile);
if (this.patchBlock == null)
{
throw new Exception("Decompress Error, cannot find patch block from the stream.");
}
BinaryReader r = new BinaryReader(patchBlock);
patchBlock.Seek(8, SeekOrigin.Begin);
int ver = r.ReadInt32();
uint checkSum0 = r.ReadUInt32();
uint checkSum1 = CheckSum.ComputeHash(patchBlock, (int)patchBlock.Length - 0x10);
VerifyCheckSum(checkSum0, checkSum1, "PatchFile", "0");
patchBlock.Seek(16, SeekOrigin.Begin);
byte lb = r.ReadByte(), hb = r.ReadByte();
if (!(lb == 0x78 && (lb * 0x100 + hb) % 31 == 0)) // zlib头标识 没有就把这两字节都当数据段好了..
{
patchBlock.Seek(-2, SeekOrigin.Current);
}
this.inflateStream = new InflateStream(patchBlock);
}
public async Task PartialStream_WithOffsetAndLength_Seek_WorksCorrectly()
{
// Arrange
#if !NET461 && !NETCOREAPP2_1
await
#endif
using var originalStream = new MemoryStream();
await originalStream.FillWithRandomBytesAsync(1024);
const int offset = 10;
const int length = 100;
#if !NET461 && !NETCOREAPP2_1
await
#endif
using var partialStream = new PartialStream(originalStream, offset, length);
// Act
const int additionalOffset = 40;
partialStream.Seek(additionalOffset, SeekOrigin.Begin);
// Assert
#if !NET461 && !NETCOREAPP2_1
await
#endif
using var outputStream = new MemoryStream();
await partialStream.CopyToAsync(outputStream);
var originalPortion = originalStream
.ToArray()
.Skip(offset + additionalOffset)
.Take(length - additionalOffset)
.ToArray();
outputStream.ToArray().Should().Equal(originalPortion);
}
private PartialStream TrySplit(Stream metaStream)
{
metaStream.Seek(0, SeekOrigin.Begin);
BinaryReader r = new BinaryReader(metaStream);
PartialStream patchBlock;
if (r.ReadUInt16() == 0x5a4d)//"MZ"
{
metaStream.Seek(-4, SeekOrigin.End);
ulong check = r.ReadUInt32();
if (check == 0xf2f7fbf3)
{
metaStream.Seek(-12, SeekOrigin.End);
int patchBlockLength = r.ReadInt32();
int noticeLength = r.ReadInt32();
metaStream.Seek(-12 - noticeLength - patchBlockLength, SeekOrigin.End);
patchBlock = new PartialStream(metaStream, metaStream.Position, patchBlockLength);
metaStream.Seek(patchBlockLength, SeekOrigin.Current);
noticeText = Encoding.Default.GetString(r.ReadBytes(noticeLength));
}
else //兼容TMS的patch.exe
{
metaStream.Seek(-8, SeekOrigin.End);
check = r.ReadUInt64();
if (check == 0xf2f7fbf3)
{
metaStream.Seek(-24, SeekOrigin.End);
long patchBlockLength = r.ReadInt64();
long noticeLength = r.ReadInt64();
metaStream.Seek(-24 - noticeLength - patchBlockLength, SeekOrigin.End);
patchBlock = new PartialStream(metaStream, metaStream.Position, patchBlockLength);
metaStream.Seek(patchBlockLength, SeekOrigin.Current);
noticeText = Encoding.Default.GetString(r.ReadBytes((int)noticeLength));
}
else
{
return(null);
}
}
}
else
{
patchBlock = new PartialStream(metaStream, 0, metaStream.Length);
}
if (patchBlock != null)
{
patchBlock.Seek(0, SeekOrigin.Begin);
r = new BinaryReader(patchBlock);
if (Encoding.ASCII.GetString(r.ReadBytes(8)) == "WzPatch\x1A")
{
patchBlock.Seek(0, SeekOrigin.Begin);
}
else
{
return(null);
}
}
return(patchBlock);
}