Iterator assertion failure. How?

[Cybulski]

Hello everyone. Welcome to my first post.

I have problem, it didn't brough me here, but maybe someone figure it out, I'm staring at this piece of code for hour. I'm trying to make directory listing class. It puts filenames and directories to vectors. It's not finished, yet not working loop:

while(iter_vsDirectory != v_sDirectories.end())
{
  while(FindNextFile(hFind, &foundFileInfo))
  {
      cout << foundFileInfo.cFileName;
      if(foundFileInfo.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
      {
          cout << " dir" << endl;
          if(s_currentDir.compare(foundFileInfo.cFileName) && s_parrentDir.compare(foundFileInfo.cFileName))
          {
               path = foundFileInfo.cFileName;
               path.append("\\*");
               v_sDirectories.push_back(path);
               cout << "Pushed back to dir vector: " << v_sDirectories.back() << endl;
           }
        }
        else
        {
             cout << " file";
             v_sFiles.push_back(foundFileInfo.cFileName);
         }
         cout << endl;
      }
   iter_vsDirectory++;
}

In meantime I'll try make this code readable.

[Ancient Dragon]

My guess is that neither of those loops will work.
1) how is iter_vsDirectory initialized? You failed to post it.

2) what is the purpose of that first loop with the iterator ? The iterator doesn't appear to be used anywhere within the loop. Adding more strings to the end of the vector might invalidate the iterator.

3) You have to call FindFirstFile() before you can start a loop for FindNextFile(). The FindNextFile() you have code will always fail.

HANDLE hFile = FindFirstFile( // blabla );
if( hFile != INVALID_HANDLE_VALUE)
{
    while( FindNextFile( // blabla ) )
    {

    }
}

[Cybulski]

My guess is that neither of those loops will work. 1) how is iter_vsDirectory initialized? You failed to post it.

2) what is the purpose of that first loop with the iterator ? The iterator doesn't appear to be used anywhere within the loop. Adding more strings to the end of the vector might invalidate the iterator.

3) You have to call FindFirstFile() before you can start a loop for FindNextFile(). The FindNextFile() you have code will always fail.

1)
vector::iterator iter_vsDirectory = v_sDirectories.begin();

2)
First loop is meant cycle trough directories. For each directory found in v_sDirectories it will call FindFirstFile, then internal loop to list files/directories inside. In case of dir found, it will append last setion of path to work recirsive in all directories inside one given at start.

If adding objects to vector invalidates iterator - thats not the way vector should work imo.

3)
It is called, before main loop.

There is result of running it:

d:\test\*
iterator: d:\test\*
.. dir

directory1 dir
Pushed back to dir vector: directory1\*

directory2 dir
Pushed back to dir vector: directory2\*

file1.txt file
file2.txt file

[Ancient Dragon]

From what you said in 2) you apparently did not post all the code. If that is correct then I suspect the problem is the iterator is getting invalidated when a new string is put into the vector.

If you are attempting to build a list of directory and their subdirectory names then maybe using recursion would be a better approach. Here is an example program how to do that. It gets all the file names as well, but you can easily modify the code to do what you want with it.

[Cybulski]

Thank you very much mr. Ancient Dragon. Your code looks very nice and reusable. Will use these ideas in my solution.

[edit]
Anyway I'll think about it some more, inserting elements shouldn't invalidate iterator.

[Cybulski]

Ok, here is my solution:

int DirectoryReader::MakeList(string p_sPath)
{
	cout << "Parameter: " << p_sPath << endl;
	struct _finddatai64_t struct_filedata;
	string s_filename = p_sPath + "\\*.*";
	string s_current = ".";
	string s_parrent = "..";
	
	cout << "Listing " << s_filename << endl;

	long nHandle = _findfirsti64(s_filename.c_str(), &struct_filedata);
	if(nHandle >= 0)
	{
		while(_findnexti64(nHandle, &struct_filedata) == 0)
		{
			if(struct_filedata.attrib & _A_SUBDIR)
			{
				if( (s_current.compare(struct_filedata.name) && s_parrent.compare(struct_filedata.name)) )
				{
					s_filename = p_sPath + "\\" + struct_filedata.name;
					cout << "Subdir found: " << s_filename << endl;
					MakeList(s_filename);
				}
				else
				{
					cout << "Dir found: "  << struct_filedata.name << endl;
				}
			}
			else
			{
				cout << "File found: " << struct_filedata.name << endl;
				m_vFilenames.push_back(struct_filedata.name);
			}
			
		}
	}
	else
	{
		cout << "Path not found." << endl;
		return -1;
	}


	return 1;
}

Two things bother me:
1) strcmp() don't want take data.name as first parameter,
2) "." should be found and displayed, but it isn't.

It works well besides that.

[Ancient Dragon]

you must have something else wrong because your function compiled ok for me. All I did was make it a simple function and declare the vector globally.

#include <iostream>
#include <string>
#include <io.h>
#include <vector>
using namespace std;

vector<string> m_vFilenames;
int MakeList(string p_sPath)
{
	cout << "Parameter: " << p_sPath << endl;
	struct _finddatai64_t struct_filedata;
	string s_filename = p_sPath + "\\*.*";
	string s_current = ".";
	string s_parrent = "..";
	
	cout << "Listing " << s_filename << endl;

	long nHandle = _findfirsti64(s_filename.c_str(), &struct_filedata);
	if(nHandle >= 0)
	{
		while(_findnexti64(nHandle, &struct_filedata) == 0)
		{
			if(struct_filedata.attrib & _A_SUBDIR)
			{
				if( (s_current.compare(struct_filedata.name) && s_parrent.compare(struct_filedata.name)) )
				{
					s_filename = p_sPath + "\\" + struct_filedata.name;
					cout << "Subdir found: " << s_filename << endl;
					MakeList(s_filename);
				}
				else
				{
					cout << "Dir found: "  << struct_filedata.name << endl;
				}
			}
			else
			{
				cout << "File found: " << struct_filedata.name << endl;
				m_vFilenames.push_back(struct_filedata.name);
			}
			
		}
	}
	else
	{
		cout << "Path not found." << endl;
		return -1;
	}


	return 1;
}

int main()
{

}

[Cybulski]

yes, it compiles and works ok, but this:

if( (s_current.compare(struct_filedata.name) && s_parrent.compare(struct_filedata.name)) )
{
    s_filename = p_sPath + "\\" + struct_filedata.name;
    cout << "Subdir found: " << s_filename << endl;
    MakeList(s_filename);
}
else
{
    cout << "Dir found: "  << struct_filedata.name << endl;
}

Should display:

Dir found: .
Dir found: ..

for every directory. It only does it for "..". Why is that?

And I had to declare additional strings and use string.compare(...) because strcmp() takes no struct_filedata.name as parameter.

[Ancient Dragon]

>>if( (s_current.compare(struct_filedata.name) && s_parrent.compare(struct_filedata.name)) )

use || operator instead of && because it can't be both at the same time.

[Cybulski]

>>if( (s_current.compare(struct_filedata.name) && s_parrent.compare(struct_filedata.name)) )

use || operator instead of && because it can't be both at the same time.

Nope, not working. Negating whole condition not working also. Only way to get list of files is using && operator, and my brain is melting while thinking why.

[mitrmkar]

"." should be found and displayed, but it isn't.

You are missing the initial match ...

...
long nHandle = _findfirsti64(s_filename.c_str(), &struct_filedata);
if(nHandle >= 0)
{
    <strong>cout << "First match is: " << struct_filedata.name << '\n';</strong>
    
    while(_findnexti64(nHandle, &struct_filedata) == 0)
    {
    ...
}

[Cybulski]

You are missing the initial match ...

...
long nHandle = _findfirsti64(s_filename.c_str(), &struct_filedata);
if(nHandle >= 0)
{
    <strong>cout << "First match is: " << struct_filedata.name << '\n';</strong>
    
    while(_findnexti64(nHandle, &struct_filedata) == 0)
    {
    ...
}

If you mean _findfirsti46(), then no. It isn't counted as first result. It only returns handle for future searches. In my previous implementation "." directory was displayed.

[mitrmkar]

If you mean _findfirsti46(), then no. It isn't counted as first result.

I disagree, MSDN says ...

_findfirst, _findfirsti64, _wfindfirst, _wfindfirsti64
Providesinformation about the first instance of a filename that matches the file specified in the filespec argument.

http://msdn.microsoft.com/en-us/library/aa246869(VS.60).aspx

So, the function takes the struct _finddatai64_t * as input for a good reason.