File Search speed - Xojo Forum

6 weeks ago

Michael M

Hello,

I have to search thru 2000 file names looking for a specific one and its really slow. I started with this code:

If f <> Nil then
  u = f.Count
  for i = 1 to u
    if not f.item(i).Directory Then
      TheFileName = f.Item(i).DisplayName
      if Instr(TheFileName,BoardCards) > 0 Then FoundIt = 1
    end if
    if FoundIt = 1 then exit
  Next
end

but it took 32 seconds to complete the search.

I then tried putting the filenames into an array first then searching but it still took 10 seconds:

If f <> Nil then
  u = f.Count
  for i = 1 to u
    if not f.item(i).Directory Then
      TheFiles(i) = f.Item(i).DisplayName
    end if
  Next
end

for i  = 1 to u
  TheFileName = TheFiles(i)
  if Instr(TheFileName,BoardCards) > 0 Then FoundIt = 1
  if FoundIt = 1 then exit
Next

Any ideas on how to make this faster? This is really bogging my program down. Any help would be appreciated.

Thanks

Answered by Jean-Yves P

See post in context

from somewhere-I-dont-remember of this forum...

Function ItemNames(extends f as folderItem, ReturnFileNames as boolean = true, ReturnFolderNames as boolean = true) As String()
  // Returns an array containing the names of child items
  // within the given folder item. Returns files and/or
  // folders, as directed by the input booleans.
  //
  // Returns an empty array if f doesn't exist, or if f
  // isn't a directory, or if both input booleans are false.
  //
  // The iteration is not recursive. On Windows, the special
  // directories "." and ".." are ignored.
  
  dim result() as string
  
  if f.Directory then
    
    #if TargetWin32
      
      // On Windows, RB's f.Item(i) is slow for folders with large
      // child item counts, so we use Declares on Windows instead.
      // Adapted from Aaron Ballman - see http://tinyurl.com/5susum
      
      Soft Declare Function FindFirstFileA Lib "Kernel32" (path as CString, data as Ptr) as Integer
      Soft Declare Function FindFirstFileW Lib "Kernel32" (path as WString, data as Ptr) as Integer
      Soft Declare Function FindNextFileA Lib "Kernel32" (handle as Integer, data as Ptr) as Boolean
      Soft Declare Function FindNextFileW Lib "Kernel32" (handle as Integer, data as Ptr) as Boolean
      Declare Sub FindClose Lib "Kernel32" (handle as Integer)
      
      dim UnicodeIsAvailable as boolean = System.IsFunctionAvailable("FindFirstFileW", "Kernel32")
      
      dim ChildData as MemoryBlock // WIN32_FIND_DATA struct
      dim ChildHandle as integer
      
      if UnicodeIsAvailable then
        
        ChildData = new MemoryBlock(592)
        ChildHandle = FindFirstFileW(f.AbsolutePath + "*.*", ChildData)
        
      else
        
        ChildData = new MemoryBlock(318)
        ChildHandle = FindFirstFileA(f.AbsolutePath + "*.*", ChildData)
        
      end if
      
      if ChildHandle <> -1 then
        
        dim ChildAttrs as UInt32 // first 4 bytes of WIN32_FIND_DATA
        dim ChildName as string
        
        // Loop through remaining items in the folder.
        
        dim FoundNextChild as Boolean
        
        do // loop through remaining children
          
          ChildAttrs = ChildData.UInt32Value(0)
          const NameOffset = 44
          
          if UnicodeIsAvailable then
            
            ChildName = ChildData.WString(NameOffset)
            FoundNextChild = FindNextFileW(ChildHandle, ChildData)
            
          else
            
            ChildName = ChildData.CString(NameOffset)
            FoundNextChild = FindNextFileA(ChildHandle, ChildData)
            
          end if
          
          // Now that we have its name and attributes, we can decide
          // whether this child should be added to our return array.
          
          dim ChildIsFolder as boolean = (ChildAttrs and UInt32(16)) <> 0
          
          if (ReturnFileNames and not ChildIsFolder) or _
            (ReturnFolderNames and ChildIsFolder) then
            
            if childName <> "." and childName <> ".." then
              result.Append(ChildName)
            end if
            
          end if
          
        loop until not FoundNextChild // should really test GetLastError for ERROR_NO_MORE_FILES
        
        FindClose ChildHandle
        
      end if
      
    #else
      
      // On non-Windows systems, pure RB code seems pretty fast.
      
      dim child as FolderItem, ub as Integer = F.Count
      
      for i as integer = 1 to ub
        
        child = f.TrueItem(i)
        
        if (ReturnFileNames and not Child.Directory) or _
          (ReturnFolderNames and Child.Directory) then
          result.Append child.Name
        end if
        
      next i
      
    #endif
    
  end if
  
  return result
  
End Function

Jeff T
Jan 10 Midlands of England, Europe

Using the collection of files in Xojo's folderitem is slow.
If you are on Windows, one technique I have seen used is to shell out to a command, and do a
DIR > LISTOFFILES.TXT
Then open LISTOFFILES.TXT as a textinput stream, reading the lot into a string.
And use INSTR() on the string.
or perhaps
DIR *searchstring*.* > LISTOFFILES.TXT to get DOS to do the wildcard search for you!
I imagine a similar technique is possible in OSX using a command such as ls
Michael M
Jan 10

Hi Jeff. I will try the shell wildcard search and report back. thanks for the info!

Jean-Yves P

Jan 10 Pre-Release Testers, Xojo Pro Answer Europe (France, Besançon)

from somewhere-I-dont-remember of this forum...

Function ItemNames(extends f as folderItem, ReturnFileNames as boolean = true, ReturnFolderNames as boolean = true) As String()
  // Returns an array containing the names of child items
  // within the given folder item. Returns files and/or
  // folders, as directed by the input booleans.
  //
  // Returns an empty array if f doesn't exist, or if f
  // isn't a directory, or if both input booleans are false.
  //
  // The iteration is not recursive. On Windows, the special
  // directories "." and ".." are ignored.
  
  dim result() as string
  
  if f.Directory then
    
    #if TargetWin32
      
      // On Windows, RB's f.Item(i) is slow for folders with large
      // child item counts, so we use Declares on Windows instead.
      // Adapted from Aaron Ballman - see http://tinyurl.com/5susum
      
      Soft Declare Function FindFirstFileA Lib "Kernel32" (path as CString, data as Ptr) as Integer
      Soft Declare Function FindFirstFileW Lib "Kernel32" (path as WString, data as Ptr) as Integer
      Soft Declare Function FindNextFileA Lib "Kernel32" (handle as Integer, data as Ptr) as Boolean
      Soft Declare Function FindNextFileW Lib "Kernel32" (handle as Integer, data as Ptr) as Boolean
      Declare Sub FindClose Lib "Kernel32" (handle as Integer)
      
      dim UnicodeIsAvailable as boolean = System.IsFunctionAvailable("FindFirstFileW", "Kernel32")
      
      dim ChildData as MemoryBlock // WIN32_FIND_DATA struct
      dim ChildHandle as integer
      
      if UnicodeIsAvailable then
        
        ChildData = new MemoryBlock(592)
        ChildHandle = FindFirstFileW(f.AbsolutePath + "*.*", ChildData)
        
      else
        
        ChildData = new MemoryBlock(318)
        ChildHandle = FindFirstFileA(f.AbsolutePath + "*.*", ChildData)
        
      end if
      
      if ChildHandle <> -1 then
        
        dim ChildAttrs as UInt32 // first 4 bytes of WIN32_FIND_DATA
        dim ChildName as string
        
        // Loop through remaining items in the folder.
        
        dim FoundNextChild as Boolean
        
        do // loop through remaining children
          
          ChildAttrs = ChildData.UInt32Value(0)
          const NameOffset = 44
          
          if UnicodeIsAvailable then
            
            ChildName = ChildData.WString(NameOffset)
            FoundNextChild = FindNextFileW(ChildHandle, ChildData)
            
          else
            
            ChildName = ChildData.CString(NameOffset)
            FoundNextChild = FindNextFileA(ChildHandle, ChildData)
            
          end if
          
          // Now that we have its name and attributes, we can decide
          // whether this child should be added to our return array.
          
          dim ChildIsFolder as boolean = (ChildAttrs and UInt32(16)) <> 0
          
          if (ReturnFileNames and not ChildIsFolder) or _
            (ReturnFolderNames and ChildIsFolder) then
            
            if childName <> "." and childName <> ".." then
              result.Append(ChildName)
            end if
            
          end if
          
        loop until not FoundNextChild // should really test GetLastError for ERROR_NO_MORE_FILES
        
        FindClose ChildHandle
        
      end if
      
    #else
      
      // On non-Windows systems, pure RB code seems pretty fast.
      
      dim child as FolderItem, ub as Integer = F.Count
      
      for i as integer = 1 to ub
        
        child = f.TrueItem(i)
        
        if (ReturnFileNames and not Child.Directory) or _
          (ReturnFolderNames and Child.Directory) then
          result.Append child.Name
        end if
        
      next i
      
    #endif
    
  end if
  
  return result
  
End Function

· Langue R likes this.

Michael M
Jan 10

Hey! That method above was nearly instant! thanks for the code :-)

· Langue R and Jeff T like this.
Jean-Yves P
Jan 10 Pre-Release Testers, Xojo Pro Europe (France, Besançon)

just seeing the code again, may be it will not work for 64 bits (windows) ...
Andre K
Jan 10 Pre-Release Testers

@Jean-YvesPochez just seeing the code again, may be it will not work for 64 bits (windows) ...
Works just fine on 64 bits Windows 10, no problem at all.

· Jean-Yves P likes this.
Jean-Yves P
Jan 10 Pre-Release Testers, Xojo Pro Europe (France, Besançon)

the code came from here : https://forum.xojo.com/conversation/post/111418