101 lines
2.0 KiB
C++
101 lines
2.0 KiB
C++
|
// CabBlockInStream.cpp
|
||
|
|
|
||
|
|
#include "StdAfx.h"
|
||
|
|
|
||
|
|
#include "../../../../C/Alloc.h"
|
||
|
|
#include "../../../../C/CpuArch.h"
|
||
|
|
|
||
|
|
#include "../../Common/StreamUtils.h"
|
||
|
|
|
||
|
|
#include "CabBlockInStream.h"
|
||
|
|
|
||
|
|
namespace NArchive {
|
||
|
|
namespace NCab {
|
||
|
|
|
||
|
|
static const UInt32 kBlockSize = (1 << 16);
|
||
|
|
|
||
|
|
bool CCabBlockInStream::Create()
|
||
|
|
{
|
||
|
|
if (!_buf)
|
||
|
|
_buf = (Byte *)::MyAlloc(kBlockSize);
|
||
|
|
return _buf != 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
CCabBlockInStream::~CCabBlockInStream()
|
||
|
|
{
|
||
|
|
::MyFree(_buf);
|
||
|
|
}
|
||
|
|
|
||
|
|
static UInt32 CheckSum(const Byte *p, UInt32 size)
|
||
|
|
{
|
||
|
|
UInt32 sum = 0;
|
||
|
|
|
||
|
|
for (; size >= 8; size -= 8)
|
||
|
|
{
|
||
|
|
sum ^= GetUi32(p) ^ GetUi32(p + 4);
|
||
|
|
p += 8;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (size >= 4)
|
||
|
|
{
|
||
|
|
sum ^= GetUi32(p);
|
||
|
|
p += 4;
|
||
|
|
}
|
||
|
|
|
||
|
|
size &= 3;
|
||
|
|
if (size > 2) sum ^= (UInt32)(*p++) << 16;
|
||
|
|
if (size > 1) sum ^= (UInt32)(*p++) << 8;
|
||
|
|
if (size > 0) sum ^= (UInt32)(*p++);
|
||
|
|
|
||
|
|
return sum;
|
||
|
|
}
|
||
|
|
|
||
|
|
HRESULT CCabBlockInStream::PreRead(ISequentialInStream *stream, UInt32 &packSize, UInt32 &unpackSize)
|
||
|
|
{
|
||
|
|
const UInt32 kHeaderSize = 8;
|
||
|
|
const UInt32 kReservedMax = 256;
|
||
|
|
Byte header[kHeaderSize + kReservedMax];
|
||
|
|
RINOK(ReadStream_FALSE(stream, header, kHeaderSize + ReservedSize))
|
||
|
|
packSize = GetUi16(header + 4);
|
||
|
|
unpackSize = GetUi16(header + 6);
|
||
|
|
if (packSize > kBlockSize - _size)
|
||
|
|
return S_FALSE;
|
||
|
|
RINOK(ReadStream_FALSE(stream, _buf + _size, packSize));
|
||
|
|
|
||
|
|
if (MsZip)
|
||
|
|
{
|
||
|
|
if (_size == 0)
|
||
|
|
{
|
||
|
|
if (packSize < 2 || _buf[0] != 0x43 || _buf[1] != 0x4B)
|
||
|
|
return S_FALSE;
|
||
|
|
_pos = 2;
|
||
|
|
}
|
||
|
|
if (_size + packSize > ((UInt32)1 << 15) + 12) /* v9.31 fix. MSZIP specification */
|
||
|
|
return S_FALSE;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (GetUi32(header) != 0) // checkSum
|
||
|
|
if (CheckSum(header, kHeaderSize + ReservedSize) != CheckSum(_buf + _size, packSize))
|
||
|
|
return S_FALSE;
|
||
|
|
|
||
|
|
_size += packSize;
|
||
|
|
return S_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
STDMETHODIMP CCabBlockInStream::Read(void *data, UInt32 size, UInt32 *processedSize)
|
||
|
|
{
|
||
|
|
if (size != 0)
|
||
|
|
{
|
||
|
|
UInt32 rem = _size - _pos;
|
||
|
|
if (size > rem)
|
||
|
|
size = rem;
|
||
|
|
memcpy(data, _buf + _pos, size);
|
||
|
|
_pos += size;
|
||
|
|
}
|
||
|
|
if (processedSize)
|
||
|
|
*processedSize = size;
|
||
|
|
return S_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
}}
|