rlm@1: // Archive/LzmaIn.cpp
rlm@1: 
rlm@1: #include "StdAfx.h"
rlm@1: 
rlm@1: #include "LzmaIn.h"
rlm@1: 
rlm@1: #include "../../Common/StreamUtils.h"
rlm@1: 
rlm@1: namespace NArchive {
rlm@1: namespace NLzma {
rlm@1:  
rlm@1: static bool CheckDictSize(const Byte *p)
rlm@1: {
rlm@1:   UInt32 dicSize = GetUi32(p);
rlm@1:   int i;
rlm@1:   for (i = 1; i <= 30; i++)
rlm@1:     if (dicSize == ((UInt32)2 << i) || dicSize == ((UInt32)3 << i))
rlm@1:       return true;
rlm@1:   return false;
rlm@1: }
rlm@1: 
rlm@1: HRESULT ReadStreamHeader(ISequentialInStream *inStream, CHeader &block)
rlm@1: {
rlm@1:   Byte sig[5 + 9];
rlm@1:   RINOK(ReadStream_FALSE(inStream, sig, 5 + 8));
rlm@1: 
rlm@1:   const Byte kMaxProp0Val = 5 * 5 * 9 - 1;
rlm@1:   if (sig[0] > kMaxProp0Val)
rlm@1:     return S_FALSE;
rlm@1: 
rlm@1:   for (int i = 0; i < 5; i++)
rlm@1:     block.LzmaProps[i] = sig[i];
rlm@1:   
rlm@1:   block.IsThereFilter = false;
rlm@1:   block.FilterMethod = 0;
rlm@1: 
rlm@1:   if (!CheckDictSize(sig + 1))
rlm@1:   {
rlm@1:     if (sig[0] > 1 || sig[1] > kMaxProp0Val)
rlm@1:       return S_FALSE;
rlm@1:     block.IsThereFilter = true;
rlm@1:     block.FilterMethod = sig[0];
rlm@1:     for (int i = 0; i < 5; i++)
rlm@1:       block.LzmaProps[i] = sig[i + 1];
rlm@1:     if (!CheckDictSize(block.LzmaProps + 1))
rlm@1:       return S_FALSE;
rlm@1:     RINOK(ReadStream_FALSE(inStream, sig + 5 + 8, 1));
rlm@1:   }
rlm@1:   UInt32 unpOffset = 5 + (block.IsThereFilter ? 1 : 0);
rlm@1:   block.UnpackSize = GetUi64(sig + unpOffset);
rlm@1:   if (block.HasUnpackSize() && block.UnpackSize >= ((UInt64)1 << 56))
rlm@1:     return S_FALSE;
rlm@1:   return S_OK;
rlm@1: }
rlm@1: 
rlm@1: }}