7zin.c

一个7ZIP的解压源码。比较详细。里面含有四种语言的实现代码。

/* 7zIn.c */

#include "7zIn.h"
#include "7zDecode.h"
#include "../../7zCrc.h"

#define RINOM(x) { if((x) == 0) return SZE_OUTOFMEMORY; }

void SzArDbExInit(CArchiveDatabaseEx *db)
{
  SzArchiveDatabaseInit(&db->Database);
  db->FolderStartPackStreamIndex = 0;
  db->PackStreamStartPositions = 0;
  db->FolderStartFileIndex = 0;
  db->FileIndexToFolderIndexMap = 0;
}

void SzArDbExFree(CArchiveDatabaseEx *db, void (*freeFunc)(void *))
{
  freeFunc(db->FolderStartPackStreamIndex);
  freeFunc(db->PackStreamStartPositions);
  freeFunc(db->FolderStartFileIndex);
  freeFunc(db->FileIndexToFolderIndexMap);
  SzArchiveDatabaseFree(&db->Database, freeFunc);
  SzArDbExInit(db);
}

/*
CFileSize GetFolderPackStreamSize(int folderIndex, int streamIndex) const 
{
  return PackSizes[FolderStartPackStreamIndex[folderIndex] + streamIndex];
}

CFileSize GetFilePackSize(int fileIndex) const
{
  int folderIndex = FileIndexToFolderIndexMap[fileIndex];
  if (folderIndex >= 0)
  {
    const CFolder &folderInfo = Folders[folderIndex];
    if (FolderStartFileIndex[folderIndex] == fileIndex)
    return GetFolderFullPackSize(folderIndex);
  }
  return 0;
}
*/

#define MY_ALLOC(T, p, size, allocFunc) { if ((size) == 0) p = 0; else \
  if ((p = (T *)allocFunc((size) * sizeof(T))) == 0) return SZE_OUTOFMEMORY; }

SZ_RESULT SzArDbExFill(CArchiveDatabaseEx *db, void * (*allocFunc)(size_t size))
{
  UInt32 startPos = 0;
  CFileSize startPosSize = 0;
  UInt32 i;
  UInt32 folderIndex = 0;
  UInt32 indexInFolder = 0;
  MY_ALLOC(UInt32, db->FolderStartPackStreamIndex, db->Database.NumFolders, allocFunc);
  for(i = 0; i < db->Database.NumFolders; i++)
  {
    db->FolderStartPackStreamIndex[i] = startPos;
    startPos += db->Database.Folders[i].NumPackStreams;
  }

  MY_ALLOC(CFileSize, db->PackStreamStartPositions, db->Database.NumPackStreams, allocFunc);

  for(i = 0; i < db->Database.NumPackStreams; i++)
  {
    db->PackStreamStartPositions[i] = startPosSize;
    startPosSize += db->Database.PackSizes[i];
  }

  MY_ALLOC(UInt32, db->FolderStartFileIndex, db->Database.NumFolders, allocFunc);
  MY_ALLOC(UInt32, db->FileIndexToFolderIndexMap, db->Database.NumFiles, allocFunc);

  for (i = 0; i < db->Database.NumFiles; i++)
  {
    CFileItem *file = db->Database.Files + i;
    int emptyStream = !file->HasStream;
    if (emptyStream && indexInFolder == 0)
    {
      db->FileIndexToFolderIndexMap[i] = (UInt32)-1;
      continue;
    }
    if (indexInFolder == 0)
    {
      /*
      v3.13 incorrectly worked with empty folders
      v4.07: Loop for skipping empty folders
      */
      for (;;)
      {
        if (folderIndex >= db->Database.NumFolders)
          return SZE_ARCHIVE_ERROR;
        db->FolderStartFileIndex[folderIndex] = i;
        if (db->Database.Folders[folderIndex].NumUnPackStreams != 0)
          break;
        folderIndex++;
      }
    }
    db->FileIndexToFolderIndexMap[i] = folderIndex;
    if (emptyStream)
      continue;
    indexInFolder++;
    if (indexInFolder >= db->Database.Folders[folderIndex].NumUnPackStreams)
    {
      folderIndex++;
      indexInFolder = 0;
    }
  }
  return SZ_OK;
}


CFileSize SzArDbGetFolderStreamPos(CArchiveDatabaseEx *db, UInt32 folderIndex, UInt32 indexInFolder)
{
  return db->ArchiveInfo.DataStartPosition + 
    db->PackStreamStartPositions[db->FolderStartPackStreamIndex[folderIndex] + indexInFolder];
}

int SzArDbGetFolderFullPackSize(CArchiveDatabaseEx *db, UInt32 folderIndex, CFileSize *resSize)
{
  UInt32 packStreamIndex = db->FolderStartPackStreamIndex[folderIndex];
  CFolder *folder = db->Database.Folders + folderIndex;
  CFileSize size = 0;
  UInt32 i;
  for (i = 0; i < folder->NumPackStreams; i++)
  {
    CFileSize t = size + db->Database.PackSizes[packStreamIndex + i];
    if (t < size)
      return SZE_FAIL;
    size = t;
  }
  *resSize = size;
  return SZ_OK;
}


/*
SZ_RESULT SzReadTime(const CObjectVector<CSzByteBuffer> &dataVector,
    CObjectVector<CFileItem> &files, UInt64 type)
{
  CBoolVector boolVector;
  RINOK(ReadBoolVector2(files.Size(), boolVector))

  CStreamSwitch streamSwitch;
  RINOK(streamSwitch.Set(this, &dataVector));

  for(int i = 0; i < files.Size(); i++)
  {
    CFileItem &file = files[i];
    CArchiveFileTime fileTime;
    bool defined = boolVector[i];
    if (defined)
    {
      UInt32 low, high;
      RINOK(SzReadUInt32(low));
      RINOK(SzReadUInt32(high));
      fileTime.dwLowDateTime = low;
      fileTime.dwHighDateTime = high;
    }
    switch(type)
    {
      case k7zIdCreationTime:
        file.IsCreationTimeDefined = defined;
        if (defined)
          file.CreationTime = fileTime;
        break;
      case k7zIdLastWriteTime:
        file.IsLastWriteTimeDefined = defined;
        if (defined)
          file.LastWriteTime = fileTime;
        break;
      case k7zIdLastAccessTime:
        file.IsLastAccessTimeDefined = defined;
        if (defined)
          file.LastAccessTime = fileTime;
        break;
    }
  }
  return SZ_OK;
}
*/

SZ_RESULT SafeReadDirect(ISzInStream *inStream, Byte *data, size_t size)
{
  #ifdef _LZMA_IN_CB
  while (size > 0)
  {
    void *inBufferSpec;
    size_t processedSize;
    const Byte *inBuffer;
    RINOK(inStream->Read(inStream, (void **)&inBufferSpec, size, &processedSize));
    inBuffer = (const Byte *)inBufferSpec;
    if (processedSize == 0 || processedSize > size)
      return SZE_FAIL;
    size -= processedSize;
    do
    {
      *data++ = *inBuffer++;
    }
    while (--processedSize != 0);
  }
  #else
  size_t processedSize;
  RINOK(inStream->Read(inStream, data, size, &processedSize));
  if (processedSize != size)
    return SZE_FAIL;
  #endif
  return SZ_OK;
}

SZ_RESULT SafeReadDirectByte(ISzInStream *inStream, Byte *data)
{
  return SafeReadDirect(inStream, data, 1);
}

SZ_RESULT SafeReadDirectUInt32(ISzInStream *inStream, UInt32 *value, UInt32 *crc)
{
  int i;
  *value = 0;
  for (i = 0; i < 4; i++)
  {
    Byte b;
    RINOK(SafeReadDirectByte(inStream, &b));
    *value |= ((UInt32)b << (8 * i));
    *crc = CRC_UPDATE_BYTE(*crc, b);
  }
  return SZ_OK;
}

SZ_RESULT SafeReadDirectUInt64(ISzInStream *inStream, UInt64 *value, UInt32 *crc)
{
  int i;
  *value = 0;
  for (i = 0; i < 8; i++)
  {
    Byte b;
    RINOK(SafeReadDirectByte(inStream, &b));
    *value |= ((UInt64)b << (8 * i));
    *crc = CRC_UPDATE_BYTE(*crc, b);
  }
  return SZ_OK;
}

int TestSignatureCandidate(Byte *testBytes)
{
  size_t i;
  for (i = 0; i < k7zSignatureSize; i++)
    if (testBytes[i] != k7zSignature[i])
      return 0;
  return 1;
}

typedef struct _CSzState
{
  Byte *Data;
  size_t Size;
}CSzData;

SZ_RESULT SzReadByte(CSzData *sd, Byte *b)
{
  if (sd->Size == 0)
    return SZE_ARCHIVE_ERROR;
  sd->Size--;
  *b = *sd->Data++;
  return SZ_OK;
}

SZ_RESULT SzReadBytes(CSzData *sd, Byte *data, size_t size)
{
  size_t i;
  for (i = 0; i < size; i++)
  {
    RINOK(SzReadByte(sd, data + i));
  }
  return SZ_OK;
}

SZ_RESULT SzReadUInt32(CSzData *sd, UInt32 *value)
{
  int i;
  *value = 0;
  for (i = 0; i < 4; i++)
  {
    Byte b;
    RINOK(SzReadByte(sd, &b));
    *value |= ((UInt32)(b) << (8 * i));
  }
  return SZ_OK;
}

SZ_RESULT SzReadNumber(CSzData *sd, UInt64 *value)
{
  Byte firstByte;
  Byte mask = 0x80;
  int i;
  RINOK(SzReadByte(sd, &firstByte));
  *value = 0;
  for (i = 0; i < 8; i++)
  {
    Byte b;
    if ((firstByte & mask) == 0)
    {
      UInt64 highPart = firstByte & (mask - 1);
      *value += (highPart << (8 * i));
      return SZ_OK;
    }
    RINOK(SzReadByte(sd, &b));
    *value |= ((UInt64)b << (8 * i));
    mask >>= 1;
  }
  return SZ_OK;
}

SZ_RESULT SzReadSize(CSzData *sd, CFileSize *value)
{
  UInt64 value64;
  RINOK(SzReadNumber(sd, &value64));
  *value = (CFileSize)value64;
  return SZ_OK;
}

SZ_RESULT SzReadNumber32(CSzData *sd, UInt32 *value)
{
  UInt64 value64;
  RINOK(SzReadNumber(sd, &value64));
  if (value64 >= 0x80000000)
    return SZE_NOTIMPL;
  if (value64 >= ((UInt64)(1) << ((sizeof(size_t) - 1) * 8 + 2)))
    return SZE_NOTIMPL;
  *value = (UInt32)value64;
  return SZ_OK;
}

SZ_RESULT SzReadID(CSzData *sd, UInt64 *value) 
{ 
  return SzReadNumber(sd, value); 
}

SZ_RESULT SzSkeepDataSize(CSzData *sd, UInt64 size)
{
  if (size > sd->Size)
    return SZE_ARCHIVE_ERROR;
  sd->Size -= (size_t)size;
  sd->Data += (size_t)size;
  return SZ_OK;
}

SZ_RESULT SzSkeepData(CSzData *sd)
{
  UInt64 size;
  RINOK(SzReadNumber(sd, &size));
  return SzSkeepDataSize(sd, size);
}

SZ_RESULT SzReadArchiveProperties(CSzData *sd)
{
  for (;;)
  {
    UInt64 type;
    RINOK(SzReadID(sd, &type));
    if (type == k7zIdEnd)
      break;
    SzSkeepData(sd);
  }
  return SZ_OK;
}

SZ_RESULT SzWaitAttribute(CSzData *sd, UInt64 attribute)
{
  for (;;)
  {
    UInt64 type;
    RINOK(SzReadID(sd, &type));
    if (type == attribute)
      return SZ_OK;
    if (type == k7zIdEnd)
      return SZE_ARCHIVE_ERROR;
    RINOK(SzSkeepData(sd));
  }
}

SZ_RESULT SzReadBoolVector(CSzData *sd, size_t numItems, Byte **v, void * (*allocFunc)(size_t size))
{
  Byte b = 0;
  Byte mask = 0;
  size_t i;
  MY_ALLOC(Byte, *v, numItems, allocFunc);
  for (i = 0; i < numItems; i++)
  {
    if (mask == 0)
    {
      RINOK(SzReadByte(sd, &b));
      mask = 0x80;
    }
    (*v)[i] = (Byte)(((b & mask) != 0) ? 1 : 0);
    mask >>= 1;
  }
  return SZ_OK;
}

SZ_RESULT SzReadBoolVector2(CSzData *sd, size_t numItems, Byte **v, void * (*allocFunc)(size_t size))
{
  Byte allAreDefined;
  size_t i;
  RINOK(SzReadByte(sd, &allAreDefined));
  if (allAreDefined == 0)
    return SzReadBoolVector(sd, numItems, v, allocFunc);
  MY_ALLOC(Byte, *v, numItems, allocFunc);
  for(i = 0; i < numItems; i++)
    (*v)[i] = 1;
  return SZ_OK;
}

SZ_RESULT SzReadHashDigests(
    CSzData *sd, 
    size_t numItems,
    Byte **digestsDefined, 
    UInt32 **digests, 
    void * (*allocFunc)(size_t size))
{
  size_t i;
  RINOK(SzReadBoolVector2(sd, numItems, digestsDefined, allocFunc));
  MY_ALLOC(UInt32, *digests, numItems, allocFunc);
  for(i = 0; i < numItems; i++)
    if ((*digestsDefined)[i])
    {
      RINOK(SzReadUInt32(sd, (*digests) + i));
    }
  return SZ_OK;
}

SZ_RESULT SzReadPackInfo(
    CSzData *sd, 
    CFileSize *dataOffset,
    UInt32 *numPackStreams,
    CFileSize **packSizes,
    Byte **packCRCsDefined,
    UInt32 **packCRCs,