zipin.cpp

由7-zip提供的压缩、解压缩程序

// Archive/ZipIn.cpp

#include "StdAfx.h"

#include "ZipIn.h"
#include "Windows/Defs.h"
#include "Common/StringConvert.h"
#include "Common/DynamicBuffer.h"
#include "../../Common/LimitedStreams.h"
#include "../../Common/StreamUtils.h"

namespace NArchive {
namespace NZip {
 
// static const char kEndOfString = '\0';
  
bool CInArchive::Open(IInStream *inStream, const UInt64 *searchHeaderSizeLimit)
{
  m_Stream = inStream;
  if(m_Stream->Seek(0, STREAM_SEEK_CUR, &m_StreamStartPosition) != S_OK)
    return false;
  m_Position = m_StreamStartPosition;
  return FindAndReadMarker(searchHeaderSizeLimit);
}

void CInArchive::Close()
{
  m_Stream.Release();
}

//////////////////////////////////////
// Markers

static inline bool TestMarkerCandidate(const Byte *p, UInt32 &value)
{
  value = p[0] | (((UInt32)p[1]) << 8) | (((UInt32)p[2]) << 16) | (((UInt32)p[3]) << 24);
  return (value == NSignature::kLocalFileHeader) ||
    (value == NSignature::kEndOfCentralDir);
}

bool CInArchive::FindAndReadMarker(const UInt64 *searchHeaderSizeLimit)
{
  m_ArchiveInfo.Clear();
  m_ArchiveInfo.StartPosition = 0;
  m_Position = m_StreamStartPosition;
  if(m_Stream->Seek(m_StreamStartPosition, STREAM_SEEK_SET, NULL) != S_OK)
    return false;

  Byte marker[NSignature::kMarkerSize];
  UInt32 processedSize; 
  ReadBytes(marker, NSignature::kMarkerSize, &processedSize);
  if(processedSize != NSignature::kMarkerSize)
    return false;
  if (TestMarkerCandidate(marker, m_Signature))
    return true;

  CByteDynamicBuffer dynamicBuffer;
  static const UInt32 kSearchMarkerBufferSize = 0x10000;
  dynamicBuffer.EnsureCapacity(kSearchMarkerBufferSize);
  Byte *buffer = dynamicBuffer;
  UInt32 numBytesPrev = NSignature::kMarkerSize - 1;
  memmove(buffer, marker + 1, numBytesPrev);
  UInt64 curTestPos = m_StreamStartPosition + 1;
  while(true)
  {
    if (searchHeaderSizeLimit != NULL)
      if (curTestPos - m_StreamStartPosition > *searchHeaderSizeLimit)
        return false;
    UInt32 numReadBytes = kSearchMarkerBufferSize - numBytesPrev;
    ReadBytes(buffer + numBytesPrev, numReadBytes, &processedSize);
    UInt32 numBytesInBuffer = numBytesPrev + processedSize;
    if (numBytesInBuffer < NSignature::kMarkerSize)
      return false;
    UInt32 numTests = numBytesInBuffer - NSignature::kMarkerSize + 1;
    for(UInt32 pos = 0; pos < numTests; pos++, curTestPos++)
    { 
      if (TestMarkerCandidate(buffer + pos, m_Signature))
      {
        m_ArchiveInfo.StartPosition = curTestPos;
        m_Position = curTestPos + NSignature::kMarkerSize;
        if(m_Stream->Seek(m_Position, STREAM_SEEK_SET, NULL) != S_OK)
          return false;
        return true;
      }
    }
    numBytesPrev = numBytesInBuffer - numTests;
    memmove(buffer, buffer + numTests, numBytesPrev);
  }
}

HRESULT CInArchive::ReadBytes(void *data, UInt32 size, UInt32 *processedSize)
{
  UInt32 realProcessedSize;
  HRESULT result = ReadStream(m_Stream, data, size, &realProcessedSize);
  if(processedSize != NULL)
    *processedSize = realProcessedSize;
  m_Position += realProcessedSize;
  return result;
}

void CInArchive::IncreaseRealPosition(UInt64 addValue)
{
  if(m_Stream->Seek(addValue, STREAM_SEEK_CUR, &m_Position) != S_OK)
    throw CInArchiveException(CInArchiveException::kSeekStreamError);
}

bool CInArchive::ReadBytesAndTestSize(void *data, UInt32 size)
{
  UInt32 realProcessedSize;
  if(ReadBytes(data, size, &realProcessedSize) != S_OK)
    throw CInArchiveException(CInArchiveException::kReadStreamError);
  return (realProcessedSize == size);
}

void CInArchive::SafeReadBytes(void *data, UInt32 size)
{
  if(!ReadBytesAndTestSize(data, size))
    throw CInArchiveException(CInArchiveException::kUnexpectedEndOfArchive);
}

void CInArchive::ReadBuffer(CByteBuffer &buffer, UInt32 size)
{
  buffer.SetCapacity(size);
  if (size > 0)
    SafeReadBytes(buffer, size);
}

Byte CInArchive::ReadByte()
{
  Byte b;
  SafeReadBytes(&b, 1);
  return b;
}

UInt16 CInArchive::ReadUInt16()
{
  UInt16 value = 0;
  for (int i = 0; i < 2; i++)
    value |= (((UInt16)ReadByte()) << (8 * i));
  return value;
}

UInt32 CInArchive::ReadUInt32()
{
  UInt32 value = 0;
  for (int i = 0; i < 4; i++)
    value |= (((UInt32)ReadByte()) << (8 * i));
  return value;
}

UInt64 CInArchive::ReadUInt64()
{
  UInt64 value = 0;
  for (int i = 0; i < 8; i++)
    value |= (((UInt64)ReadByte()) << (8 * i));
  return value;
}

bool CInArchive::ReadUInt32(UInt32 &value)
{
  value = 0;
  for (int i = 0; i < 4; i++)
  {
    Byte b;
    if (!ReadBytesAndTestSize(&b, 1))
      return false;
    value |= (UInt32(b) << (8 * i));
  }
  return true;
}


AString CInArchive::ReadFileName(UInt32 nameSize)
{
  if (nameSize == 0)
    return AString();
  SafeReadBytes(m_NameBuffer.GetBuffer(nameSize), nameSize);
  m_NameBuffer.ReleaseBuffer(nameSize);
  return m_NameBuffer;
}

void CInArchive::GetArchiveInfo(CInArchiveInfo &archiveInfo) const
{
  archiveInfo = m_ArchiveInfo;
}

void CInArchive::ThrowIncorrectArchiveException()
{
  throw CInArchiveException(CInArchiveException::kIncorrectArchive);
}

static UInt32 GetUInt32(const Byte *data)
{
  return 
      ((UInt32)(Byte)data[0]) |
      (((UInt32)(Byte)data[1]) << 8) |
      (((UInt32)(Byte)data[2]) << 16) |
      (((UInt32)(Byte)data[3]) << 24);
}


void CInArchive::ReadExtra(UInt32 extraSize, CExtraBlock &extraBlock, 
    UInt64 &unpackSize, UInt64 &packSize, UInt64 &localHeaderOffset, UInt32 &diskStartNumber)
{
  extraBlock.Clear();
  UInt32 remain = extraSize;
  while(remain >= 4)
  {
    CExtraSubBlock subBlock;
    subBlock.ID = ReadUInt16();
    UInt32 dataSize = ReadUInt16();
    remain -= 4;
    if (dataSize > remain) // it's bug
      dataSize = remain;
    if (subBlock.ID == 0x1)
    {
      if (unpackSize == 0xFFFFFFFF)
      {
        if (dataSize < 8)
          break;
        unpackSize = ReadUInt64();
        remain -= 8;
        dataSize -= 8;
      }
      if (packSize == 0xFFFFFFFF)
      {
        if (dataSize < 8)
          break;
        packSize = ReadUInt64();
        remain -= 8;
        dataSize -= 8;
      }
      if (localHeaderOffset == 0xFFFFFFFF)
      {
        if (dataSize < 8)
          break;
        localHeaderOffset = ReadUInt64();
        remain -= 8;
        dataSize -= 8;
      }
      if (diskStartNumber == 0xFFFF)
      {
        if (dataSize < 4)
          break;
        diskStartNumber = ReadUInt32();
        remain -= 4;
        dataSize -= 4;
      }
      for (UInt32 i = 0; i < dataSize; i++)
        ReadByte();
    }
    else
    {
      ReadBuffer(subBlock.Data, dataSize);
      extraBlock.SubBlocks.Add(subBlock);
    }
    remain -= dataSize;
  }
  IncreaseRealPosition(remain);
}

HRESULT CInArchive::ReadHeaders(CObjectVector<CItemEx> &items, CProgressVirt *progress)
{
  // m_Signature must be kLocalFileHeaderSignature or
  // kEndOfCentralDirSignature
  // m_Position points to next byte after signature

  items.Clear();

  if (progress != 0)
  {
    UInt64 numItems = items.Size();
    RINOK(progress->SetCompleted(&numItems));
  }

  while(m_Signature == NSignature::kLocalFileHeader)
  {
    // FSeek points to next byte after signature
    // NFileHeader::CLocalBlock localHeader;
    CItemEx item;
    item.LocalHeaderPosition = m_Position - m_StreamStartPosition - 4; // points to signature;
    
    // SafeReadBytes(&localHeader, sizeof(localHeader));

    item.ExtractVersion.Version = ReadByte();
    item.ExtractVersion.HostOS = ReadByte();
    item.Flags = ReadUInt16() & NFileHeader::NFlags::kUsedBitsMask; 
    item.CompressionMethod = ReadUInt16();
    item.Time =  ReadUInt32();
    item.FileCRC = ReadUInt32();
    item.PackSize = ReadUInt32();
    item.UnPackSize = ReadUInt32();
    UInt32 fileNameSize = ReadUInt16();
    item.LocalExtraSize = ReadUInt16();
    item.Name = ReadFileName(fileNameSize);
    /*
    if (!NItemName::IsNameLegal(item.Name))