Paper on Efficient File I/O in VB

Here's something I put together last night and modified a bit this morning. Basically this is, in my opinion, the best way of doing file I/O in VB using native VB functions.

My code is the third method.
Its fast, but its also in a loop, so that the application won't look crashed.

Let me know what you think ...

impressive!

CopyMemory is superfast

i got:
1) = 3910 (Normal Input)
2) = 4351 (Normal Do...Loop)
3) = 3799 (Yours)

which means that in my case, your method was quicker than BOTH!

Yes it is quite cool isn't it :)

i'm guessing that the usual functions, and string appending basically copies memory accross at some point (it would have to!), but your method skips the error checking etc. so its quicker.

i wonder what the downsides are?

if its dangerous to use?

If it's not then i'll use it all the time :)

be worth finding out...?

Whjy not just use Get?

Code times :
Input(Lof(), #filenum) 5919
Normal Do...Loop 7721
Modified Do...Loop 5628
Get: 180

Buffer sizes : 438899,438899,438899,438899
Buffers equal : True

Post your code ?

even if it is faster with Get, using CopyMemory just for the String appending bit is faster than str1 = str1 & str2

and we all can use that!

there are lots of ways to speed up your apps when it comes to string manipulation though.

check this out...

ignore prev thread and dont download, i got me no.s mixed up.

DAMN it, i feel silly now:(

Quote:

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Originally posted by plenderj
Post your code ?

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apend it to your code

Code:

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dim time4 as long
dim strBuff5 as string

    Debug.Print "6/5) Now using get"
    time4 = GetTickCount
    Open myFile For Binary As #1
        strBuff5 = Space(LOF(1))
        Get #1, , strBuff5
    Close #1
    time4 = GetTickCount - time4
   
   
   
'' Display results, and confirm that resulting file buffers are equal
''
    Debug.Print "Code times : " & vbCrLf & _
            "  Input(Lof(), #filenum)" & vbTab & time1 & vbCrLf & _
            "  Normal Do...Loop    " & vbTab & time2 & vbCrLf & _
            "  Modified Do...Loop  " & vbTab & time3 & vbCrLf & _
            "  Get: " & vbTab & time4 & vbCrLf & vbCrLf & _
            "  Buffer sizes  :    " & vbTab & Len(strBuff) & "," & Len(strBuff2) & "," & Len(strBuff4) & "," & Len(strBuff5) & vbCrLf & _
            "  Buffers equal :    " & vbTab & ((strBuff2 = strBuff4) And (strBuff = strBuff2))

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using Get took 20 milliseconds on mine, you sure thats right!?!?

Hmm you're right!
It pisses all over my code.
I had never considered using Get() to input the data...

Nice one :)

heres something interesting...

Jamie, why not start a VB Optimisations thread in Chit Chat?

plonk your code in it too. i'll add a few ideas.

people will argue about who's code is faster that who's etc, and add their own. everyone will learn...

very :cool:

Why chit-chat ?
We get post count increases if we do it here ;)

but wont we get slapped by the admins etc for that? :eek:

oooo a slapping. I like the idea of that ;)
Heh, have you seen the Sentience thread in the Games&Graphics Programming forum ?
About 35 pages full of ****e :)

aha, the plot thickens :D heheheh

Naw, as long as it's VB related and relatively useful then it's fine.

Oi, Irish! Watch it! ;)

35 pages of shiite? I'll kick yo ass - that thread's essential to Sentience!

Yeah but man you've got to admit it, there's a serious amount of crap in there too :)

<chant> fight, fight, fight...

Most of it posted by you, ya barmy Mick!

I beg to differ !

As mentioned before: GET is REALLY faster.
My code looks like this (I do not use the Space function, Rather the String function)

Code:

---

   
'' "Clear" the Immediate Window
''
    Dim i As Long
    For i = 0 To 50
        Debug.Print
    Next
   
'' A few declarations outside of the timing loops
''
    Dim myFile As String: myFile = "c:\plenderjTestFile.txt"
    Dim myLof As Long, time1 As Long, time2 As Long, time3 As Long, time4 As Long
    Dim strBuff As String, strBuff2 As String, strBuff3 As String, strBuff4 As String, strBuff5 As String, currPos As Long
   

'' Create a test file to work with
''
    Debug.Print "1/6) Creating test file ..."
    Open myFile For Output As #1
        For i = 0 To 50000
            Print #1, i
        Next
    Close #1
    Debug.Print "2/6) Created! , File length : " & FileLen(myFile)
   
   
    myLof = FileLen(myFile)
   
'' First test. Input entire length of file into memory using Input()
''
    Debug.Print "3/6) Input(Lof(), #fileNumber)"
    time1 = GetTickCount
    Open myFile For Binary As #1
        strBuff = Input(myLof, 1)
    Close #1
    time1 = GetTickCount - time1
           
       
'' Second test. Read in and append 4096 blocks to a buffer using a Do...Loop
''
    Debug.Print "4/6) Now using normal Do...Loop"
    time2 = GetTickCount
    Open myFile For Binary As #1
        Do Until Loc(1) = myLof
            strBuff2 = strBuff2 & Input(4096, 1)
        Loop
    Close #1
    time2 = GetTickCount - time2
           
           
'' Third test. Read in and append 4096 blocks to a buffer using a Do...Loop and special code for appending
''
    Debug.Print "5/6) Now using modified Do...Loop"
    time3 = GetTickCount
    strBuff4 = Space(myLof)
    Open myFile For Binary As #1
        Do Until Loc(1) = myLof
            strBuff3 = Input(4096, 1)
            CopyMemory ByVal StrPtr(strBuff4) + currPos, ByVal StrPtr(strBuff3), LenB(strBuff3)
            currPos = currPos + LenB(strBuff3)
        Loop
    Close #1
    time3 = GetTickCount - time3

'' Fourth Test
    Debug.Print "6/6) Now using GET, NO LOOP"
    time4 = GetTickCount
    Open myFile For Binary As #1
        strBuff5 = String(myLof, vbNull)
        Get #1, , strBuff5
    Close #1
    time4 = GetTickCount - time4
   
'' Display results, and confirm that resulting file buffers are equal
''
    MsgBox "Code times : " & vbCrLf & _
            "  Input(Lof(), #filenum)" & vbTab & time1 & vbCrLf & _
            "  Normal Do...Loop    " & vbTab & time2 & vbCrLf & _
            "  Modified Do...Loop  " & vbTab & time3 & vbCrLf & _
            "  And when using GET" & vbTab & time4 & vbCrLf & vbCrLf & vbCrLf & _
            "  Buffer sizes  :    " & vbTab & Len(strBuff) & "," & Len(strBuff2) & "," & Len(strBuff4) & "," & Len(strBuff5) & vbCrLf & _
            "  Buffers equal :    " & vbTab & ((strBuff2 = strBuff4) And (strBuff = strBuff2) And (strBuff = strBuff5))
   
    End

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See the difference?

Quote:

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Originally posted by plenderj
I beg to differ !

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Most of the CRAP is posted by you - mine are all valuable posts. Buttmunch.

alas, another meaningfull thread has been sabotaged and regulated to Chit Chat :D ;)

Quote:

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Originally posted by darre1
alas, another meaningfull thread has been sabotaged and regulated to Chit Chat :D ;)

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You don't know what "regulated" means do you ? :)

:p :p :p :p :p

oh PANTS!!!!

i spelt it wrong

relegated (probably still spelt wrong)


PS: up yours ;) :D

Quote:

---

Originally posted by darre1
:p :p :p :p :p

oh PANTS!!!!

i spelt it wrong

relegated (probably still spelt wrong)


PS: up yours ;) :D

---

bah. suck me right off ! ;)

mad oirishman :D

c'est moi :)

er, what part of France is Ireland in? :eek:

Kinda over on the side...

sacré bleu!!! vous suis imbecile. :p

vous ETES un embicile ?

vous etes un tete de merde!

te-hee

Quote:

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Originally posted by darre1
sacré bleu!!! vous suis imbecile. :p

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vous êtes. not vous suis. :)

Quote:

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Originally posted by yrwyddfa
vous ETES un embicile ?

vous etes un tete de merde!

te-hee

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je nes compredes pas :D

i used to say that alot in school :rolleyes:

Quote:

---

Originally posted by yrwyddfa
vous ETES un embicile ?

vous etes un tete de merde!

te-hee

---

je nes comprendes pas :D

i used to say that alot in school :rolleyes: