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// Archive/GZipIn.cpp
#include "StdAfx.h"
#include "GZipIn.h"
#include "Common/Defs.h"
#include "Common/MyCom.h"
#include "Windows/Defs.h"
#include "../../Common/StreamUtils.h"
extern "C"
{
#include "../../../../C/7zCrc.h"
}
namespace NArchive {
namespace NGZip {
HRESULT CInArchive::ReadBytes(ISequentialInStream *inStream, void *data, UInt32 size)
{
RINOK(ReadStream_FALSE(inStream, data, size));
m_Position += size;
return S_OK;
}
HRESULT CInArchive::ReadByte(ISequentialInStream *inStream, Byte &value, UInt32 &crc)
{
RINOK(ReadBytes(inStream, &value, 1));
crc = CRC_UPDATE_BYTE(crc, value);
return S_OK;
}
HRESULT CInArchive::ReadUInt16(ISequentialInStream *inStream, UInt16 &value, UInt32 &crc)
{
value = 0;
for (int i = 0; i < 2; i++)
{
Byte b;
RINOK(ReadByte(inStream, b, crc));
value |= (UInt16(b) << (8 * i));
}
return S_OK;
}
HRESULT CInArchive::ReadUInt32(ISequentialInStream *inStream, UInt32 &value, UInt32 &crc)
{
value = 0;
for (int i = 0; i < 4; i++)
{
Byte b;
RINOK(ReadByte(inStream, b, crc));
value |= (UInt32(b) << (8 * i));
}
return S_OK;
}
HRESULT CInArchive::ReadZeroTerminatedString(ISequentialInStream *inStream, AString &resString, UInt32 &crc)
{
resString.Empty();
for (;;)
{
Byte c;
RINOK(ReadByte(inStream, c, crc));
if (c == 0)
return S_OK;
resString += char(c);
}
}
HRESULT CInArchive::ReadHeader(ISequentialInStream *inStream, CItem &item)
{
item.Clear();
m_Position = 0;
UInt16 signature;
UInt32 crc = CRC_INIT_VAL;;
RINOK(ReadUInt16(inStream, signature, crc));
if (signature != kSignature)
return S_FALSE;
RINOK(ReadByte(inStream, item.CompressionMethod, crc));
RINOK(ReadByte(inStream, item.Flags, crc));
RINOK(ReadUInt32(inStream, item.Time, crc));
RINOK(ReadByte(inStream, item.ExtraFlags, crc));
RINOK(ReadByte(inStream, item.HostOS, crc));
if (item.ExtraFieldIsPresent())
{
UInt16 extraSize;
RINOK(ReadUInt16(inStream, extraSize, crc));
item.Extra.SetCapacity(extraSize);
RINOK(ReadBytes(inStream, item.Extra, extraSize));
crc = CrcUpdate(crc, item.Extra, extraSize);
}
if (item.NameIsPresent())
RINOK(ReadZeroTerminatedString(inStream, item.Name, crc));
if (item.CommentIsPresent())
RINOK(ReadZeroTerminatedString(inStream, item.Comment, crc));
if (item.HeaderCRCIsPresent())
{
UInt16 headerCRC;
UInt32 dummy = 0;
RINOK(ReadUInt16(inStream, headerCRC, dummy));
if ((UInt16)CRC_GET_DIGEST(crc) != headerCRC)
return S_FALSE;
}
return S_OK;
}
HRESULT CInArchive::ReadPostHeader(ISequentialInStream *inStream, CItem &item)
{
UInt32 dummy = 0;
RINOK(ReadUInt32(inStream, item.FileCRC, dummy));
return ReadUInt32(inStream, item.UnPackSize32, dummy);
}
}}
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