[Solved] Error allocating memory for a 6 MB file

[TheDcoder]

Hello! I am having problem with using file read...

Here is my code:

#include <FileConstants.au3>
#include <MsgBoxConstants.au3>
#include <StringConstants.au3>

Local Const $CHUNK = 1024
Local $hFile = FileOpen(@ScriptDir & '\test.bin', $FO_APPEND)
Local $iCurrentPos = 0

Do
    $iCurrentPos += $CHUNK
    $bFileSetPos = FileSetPos($hFile, $iCurrentPos, $FILE_END)
    $vData = FileRead($hFile)
    $vData = BinaryToString($vData)
    MsgBox(0, 0, $vData)
    $iStringPos = StringInStr($vData, "Test", $STR_NOCASESENSEBASIC)
Until Not ($iStringPos = 0) Or $bFileSetPos = False
FileClose($hFile)

MsgBox($MB_OK, "Success", $iStringPos)

Here is the 6 MB file: <Attachment Deleted>

 

Thanks in Advance! TD

Edited February 13, 2016 by TheDcoder
Appended [Solved] to title & deleted attachment

[water]

You have to define the number of bytes to read in FileRead as well. Else you read the whole file every time.

[TheDcoder]

@water Huh?

I remember that FileRead reads from the position set by FileSetPos, my previous version of code just did that.

Even if it did read the whole file, I think it would be easy to store 6 MB of data... This is my test script which I use to read the whole file:

ConsoleWrite(FileRead(@ScriptDir & '\test.bin'))
MsgBox(0,0,0)

1 hour ago, water said:

You have to define the number of bytes to read in FileRead as well

I tried that now, I set the number of bytes to read to $iCurrentPos, Now for some reason the script is looping indefinitely.

 

TD

[TheDcoder]

@water Huh?

I remember that FileRead reads from the position set by FileSetPos, my previous version of code just did that.

Even if it did read the whole file, I think it would be easy to store 6 MB of data... This is my test script which I use to read the whole file:

ConsoleWrite(FileRead(@ScriptDir & '\test.bin'))
MsgBox(0,0,0)

1 hour ago, water said:

You have to define the number of bytes to read in FileRead as well

I tried that now, I set the number of bytes to read to $iCurrentPos, Now for some reason the script is looping indefinitely.

 

TD

[water]

Can you please describe what you try to do?
Now you

• Open the file in write/append mode - but you only read the content
• You use FileSetPos from the end of the file - do you really try to read the file from end to start?
• You increment $iCurrentPos - but my understanding is that this should be a negative number for FileSetPos from the end of the file
• You always read the file from the set position to the end - the longer you loop the more data you read
• Error checking is not done when an error could occur (after FileSetPos or FileRead) - so you might process data in an inconsistant state

Edited February 13, 2016 by water

[TheDcoder]

3 minutes ago, water said:

Can you please describe what you try to do?

I am trying to read the footer of a file (in this case "Test" indicates where the footer starts from)

5 minutes ago, water said:

Open the file in write/append mode - but you only read the content

The code is from a function in my original code, I returned the read data.

5 minutes ago, water said:

You use FileSetPos from the end of the file - do you really try to read the file from end to start?

Yep, it is necessary to read the footer

6 minutes ago, water said:

You increment $iCurrentPos - but my understanding is that this should be a negative number to read from the end of the file

Silly me! That fixed the problem

 

Thanks water! You solved my problem by asking questions! That is simply great!

[TheDcoder]

This is the code which worked for me :

#include <FileConstants.au3>
#include <MsgBoxConstants.au3>
#include <StringConstants.au3>

Local Const $CHUNK = 1024
Local $hFile = FileOpen(@ScriptDir & '\test.bin', $FO_APPEND)
Local $iCurrentPos = 0
Local $bFileSetPos = True

Do
    $iCurrentPos -= $CHUNK
    $bFileSetPos = FileSetPos($hFile, $iCurrentPos, $FILE_END)
    $vData = FileRead($hFile, $iCurrentPos)
    $vData = BinaryToString($vData)
    $iStringPos = StringInStr($vData, "Test", $STR_NOCASESENSEBASIC)
Until Not ($iStringPos = 0) Or $bFileSetPos = False
FileClose($hFile)

MsgBox($MB_OK, "Success", $iStringPos)

But I still don't understand why there was a memory allocation error in my faulty code

[water]

Glad the problem could be solved  
But I still think it is a lot of overhead to check a 6MB file

[TheDcoder]

Just now, water said:

lot of overhead to check a 6MB file

Any suggestions?

[water]

Read the file in one go.

[TheDcoder]

@water . I normally process larger files, this was tiny compared to them

[water]

Ah, new information

[LarsJ]

If you need the footer only, then read the file from the end.

Edited February 13, 2016 by LarsJ

[TheDcoder]

Just now, LarsJ said:

If you need the footer only, the read the file from the end.

?

[LarsJ]

My grandmother can code that - while she is knitting at the same time. She can multitask. You have to figure that out yourself young man.

[TheDcoder]

11 minutes ago, LarsJ said:

My grandmother can code that

Your grandma is Augusta Ada!?

[water]

No, his grandmother is a woman. And women are able to multitask. At least that's what they try to tell us.

[water]

Guess what I found in the help file

"A count value that is too large can lead to AutoIt stopping with a memory allocation failure."

[TheDcoder]

Just now, water said:

No, his grandmother is a woman

https://en.wikipedia.org/wiki/Ada_Lovelace

[TheDcoder]

@water Oh !