采用管理库提取文件，进入一个缓冲区流

StackOverflow https://stackoverflow.com/questions/2327784

  •  22-09-2019
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题

我需要的是能够提取的文件中的一个。rar文件成流。我创建一个测试案例得到感觉如何使用 下载源.我一直在寻找和修补一段时间，但我不知道如何使用的图书馆。我很惊讶我不能即使发现的文件或一个教程，考虑如何共同点。rar档案。

我做了一点进展，在我自己的，但它并不总是有效。某些文件被提取适当的。其他文件都混乱了由于某些原因(但不是 完全 "垃圾"的二进制数据)。我所知道迄今为止，通常(但不是总是):

  • 不工作文件 fileInfo.Method = 48.他们似乎是文件有一个压缩比率的100％-即没有压缩

  • 工作文件 fileInfo.Method = 49, 50, 51, 52, 或 53, ，这对应于压缩速度，速度最快，快，正常的，好的，好的

但我不知道为什么，是。仍然找不到文件或工作实例。

下面是测试的情况来源，我迄今为止，和一个 例rar 那时取用这种程序，具有两种工作和不能工作文件。

/* put in the same directory as the unrar source files
 * compiling with:
 *   make clean
 *   make lib
 *   g++ rartest.cpp -o rartest libunrar.so -lboost_filesystem
 */

#include  <cstring>
#include  <iostream>
#include  <fstream>

#include  <boost/filesystem.hpp>

#define _UNIX
#define  RARDLL
#include  "dll.hpp"

using namespace std;
namespace fs = boost::filesystem;

//char fileName[100] = "testout0.jpg\0";
//
//// doens't work
//int PASCAL ProcessDataProc(unsigned char* buffer, int buffLen) {
//  cout  << "writing..." << endl;
//  ofstream outFile(fileName);
//  cout << buffLen << endl;
//  cout << outFile.write((const char*)buffer, buffLen) << endl;
//  cout  << "done writing..." << endl;
//  fileName[7]++;
//}

int CALLBACK CallbackProc(unsigned int msg, long myBuffer, long rarBuffer, long bufferLen) {
  switch(msg) {
    case UCM_CHANGEVOLUME:
      break;
    case UCM_PROCESSDATA:
      memcpy((char*)myBuffer, (char*)rarBuffer, bufferLen);
      break;
    case UCM_NEEDPASSWORD:
      break;
  }
  return 1;
}

int main(int argc, char* argv[]) {
  if (argc != 2)
    return 0;
  ifstream archiveStream(argv[1]);
  if (!archiveStream.is_open())
    cout << "fstream couldn't open file\n";

  // declare and set parameters
  HANDLE rarFile;
  RARHeaderDataEx fileInfo;
  RAROpenArchiveDataEx archiveInfo;
  memset(&archiveInfo, 0, sizeof(archiveInfo));
  archiveInfo.CmtBuf = NULL;
  //archiveInfo.OpenMode = RAR_OM_LIST;
  archiveInfo.OpenMode = RAR_OM_EXTRACT;
  archiveInfo.ArcName = argv[1];

  // Open file
  rarFile = RAROpenArchiveEx(&archiveInfo);
  if (archiveInfo.OpenResult != 0) {
    RARCloseArchive(rarFile);
    cout  << "unrar couldn't open" << endl;
    exit(1);
  }
  fileInfo.CmtBuf = NULL;

  cout  << archiveInfo.Flags << endl;

  // loop through archive
  int numFiles = 0;
  int fileSize;
  int RHCode;
  int PFCode;
  while(true) {
    RHCode = RARReadHeaderEx(rarFile, &fileInfo);
    if (RHCode != 0) break;

    numFiles++;
    fs::path path(fileInfo.FileName);
    fileSize = fileInfo.UnpSize;

    cout << fileInfo.Method << " " << fileInfo.FileName << " (" << fileInfo.UnpSize << ")" << endl;

    char fileBuffer[fileInfo.UnpSize];

    // not sure what this does
    //RARSetProcessDataProc(rarFile, ProcessDataProc);

    // works for some files, but not for others
    RARSetCallback(rarFile, CallbackProc, (long) &fileBuffer);
    PFCode = RARProcessFile(rarFile, RAR_TEST, NULL, NULL);

    // properly extracts to a directory... but I need a stream
    // and I don't want to write to disk, read it, and delete from disk
    //PFCode = RARProcessFile(rarFile, RAR_EXTRACT, ".", fileInfo.FileName);

    // just skips
    //PFCode = RARProcessFile(rarFile, RAR_SKIP, NULL, NULL);

    if (PFCode != 0) {
      RARCloseArchive(rarFile);
      cout  << "error processing this file\n" << endl;
      exit(1);
    }
    ofstream outFile(path.filename().c_str());
    outFile.write(fileBuffer, fileSize);
  }
  if (RHCode != ERAR_END_ARCHIVE)
    cout  << "error traversing through archive: " << RHCode << endl;
  RARCloseArchive(rarFile);

  cout  << "num files: " << numFiles << endl;

}

更新：

我已经找到了一个文件，该文件似乎是(索赔是什么？) 的 文档, 但根据该文件，我没有做错任何事。我想我可能会被迫采CRC检查缓冲区和执行一个解决办法，如果它失败。

解决方案源(谢谢，丹尼斯Krjuchkov!):

/* put in the same directory as the unrar source files
 * compiling with:
 *   make clean
 *   make lib
 *   g++ rartest.cpp -o rartest libunrar.so -lboost_filesystem
 */

#include  <cstring>
#include  <iostream>
#include  <fstream>

#include  <boost/filesystem.hpp>
#include    <boost/crc.hpp>

#define _UNIX
#define  RARDLL
#include  "dll.hpp"

using namespace std;
namespace fs = boost::filesystem;

//char fileName[100] = "testout0.jpg\0";
//
//// doens't work
//int PASCAL ProcessDataProc(unsigned char* buffer, int buffLen) {
//  cout  << "writing..." << endl;
//  ofstream outFile(fileName);
//  cout << buffLen << endl;
//  cout << outFile.write((const char*)buffer, buffLen) << endl;
//  cout  << "done writing..." << endl;
//  fileName[7]++;
//}

int CALLBACK CallbackProc(unsigned int msg, long myBufferPtr, long rarBuffer, long bytesProcessed) {
  switch(msg) {
    case UCM_CHANGEVOLUME:
      return -1;
      break;
    case UCM_PROCESSDATA:
      memcpy(*(char**)myBufferPtr, (char*)rarBuffer, bytesProcessed);
      *(char**)myBufferPtr += bytesProcessed;
      return 1;
      break;
    case UCM_NEEDPASSWORD:
      return -1;
      break;
  }
}

int main(int argc, char* argv[]) {
  if (argc != 2)
    return 0;
  ifstream archiveStream(argv[1]);
  if (!archiveStream.is_open())
    cout << "fstream couldn't open file\n";

  // declare and set parameters
  RARHANDLE rarFile;  // I renamed this macro in dll.hpp for my own purposes
  RARHANDLE rarFile2;
  RARHeaderDataEx fileInfo;
  RAROpenArchiveDataEx archiveInfo;
  memset(&archiveInfo, 0, sizeof(archiveInfo));
  archiveInfo.CmtBuf = NULL;
  //archiveInfo.OpenMode = RAR_OM_LIST;
  archiveInfo.OpenMode = RAR_OM_EXTRACT;
  archiveInfo.ArcName = argv[1];

  // Open file
  rarFile = RAROpenArchiveEx(&archiveInfo);
  rarFile2 = RAROpenArchiveEx(&archiveInfo);
  if (archiveInfo.OpenResult != 0) {
    RARCloseArchive(rarFile);
    cout  << "unrar couldn't open" << endl;
    exit(1);
  }
  fileInfo.CmtBuf = NULL;

//  cout  << archiveInfo.Flags << endl;

  // loop through archive
  int numFiles = 0;
  int fileSize;
  int RHCode;
  int PFCode;
  int crcVal;
  bool workaroundUsed = false;
    char currDir[2] = ".";
    char tmpFile[11] = "buffer.tmp";
  while(true) {
    RHCode = RARReadHeaderEx(rarFile, &fileInfo);
    if (RHCode != 0) break;
    RARReadHeaderEx(rarFile2, &fileInfo);

    numFiles++;
    fs::path path(fileInfo.FileName);
    fileSize = fileInfo.UnpSize;
    crcVal = fileInfo.FileCRC;

    cout << dec << fileInfo.Method << " " << fileInfo.FileName << " (" << fileInfo.UnpSize << ")" << endl;
    cout << " " << hex << uppercase << crcVal << endl;

    char fileBuffer[fileSize];
    char* bufferPtr = fileBuffer;

    // not sure what this does
    //RARSetProcessDataProc(rarFile, ProcessDataProc);

    // works for some files, but not for others
    RARSetCallback(rarFile, CallbackProc, (long) &bufferPtr);
    PFCode = RARProcessFile(rarFile, RAR_TEST, NULL, NULL);

    // properly extracts to a directory... but I need a stream
    // and I don't want to write to disk, read it, and delete from disk
//    PFCode = RARProcessFile(rarFile, RAR_EXTRACT, currDir, fileInfo.FileName);

    // just skips
    //PFCode = RARProcessFile(rarFile, RAR_SKIP, NULL, NULL);

    if (PFCode != 0) {
      RARCloseArchive(rarFile);
      cout  << "error processing this file\n" << endl;
      exit(1);
    }

    // crc check
    boost::crc_32_type crc32result;
    crc32result.process_bytes(&fileBuffer, fileSize);
    cout << " " << hex << uppercase << crc32result.checksum() << endl;

    // old workaround - crc check always succeeds now!
    if (crcVal == crc32result.checksum()) {
      RARProcessFile(rarFile2, RAR_SKIP, NULL, NULL);
    }
    else {
      workaroundUsed = true;
      RARProcessFile(rarFile2, RAR_EXTRACT, currDir, tmpFile);
      ifstream inFile(tmpFile);
      inFile.read(fileBuffer, fileSize);
    }

    ofstream outFile(path.filename().c_str());
    outFile.write(fileBuffer, fileSize);
  }
  if (workaroundUsed) remove(tmpFile);
  if (RHCode != ERAR_END_ARCHIVE)
    cout  << "error traversing through archive: " << RHCode << endl;
  RARCloseArchive(rarFile);

  cout  << dec << "num files: " << numFiles << endl;

}
有帮助吗？

解决方案

我不熟悉管理之后，快速阅读一个文件，我认为你是假设CallbackProc被称为一次每文件。然而，我认为管理可以叫它多次。它解开一些数据然后电话 CallbackProc, 然后解开下一块的数据，并再次呼叫 CallbackProc, ，迭代过程，直至所有数据进行处理。你应该还记得多少字节实际上写入缓冲区，并追加新的数据，在相应的抵消。

其他提示

我找不到任何文档网络，但也有 例 你可以使用：

去 http://www.krugle.com, ，并在左下角的网页，输入关键字样 RAROpenArchiveEx.你会看到头部和源文件，从各种公开来源的项目，使用管理库。

应该让你去。

你似乎已经发布一些源码，但是没有实际的问题。

你考虑看看 Rarlabs反馈页 (它指向他们 论坛

此外，见： 这篇文章

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