Filesize Conversion

[scottgp]

I worked with a woman who was supposedly in IT for at least 10 years, who was previously an Oracle instructor, and asked me how to convert K to MB. Scary. Scott

[riced]

What if file is exactly 1024 or 1048576 bytes? Not likely but not impossible, I can generate one of either size with ease. :)

Regards David R --------------------------------------------------------------- "Every program eventually becomes rococo, and then rubble." - Alan Perlis The only valid measurement of code quality: WTFs/minute.

[Luc Pattyn]

right. and doesn't Dim FormattedFileSize As Double deserve some attention too? :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

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[riced]

Yup. But I guess he has Option Strict Off either intentionally or by default. That allows it to compile. But there's even worse when you look at it more closely e.g. a file of 1023 bytes returns 1,023.00KB. :-D He did say it was working so I suppose he tested it. :laugh:

Regards David R --------------------------------------------------------------- "Every program eventually becomes rococo, and then rubble." - Alan Perlis The only valid measurement of code quality: WTFs/minute.

[Luc Pattyn]

I have finally written a function to do exactly what I need to be done. Please look at the code below and benefit from it if you wish I think he meant: no need for me to test it, just publish and wait a while. Not sure it will still do what "needs to be done" when we are through... :)

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[riced]

I decide to benefit and wrote something that does work. :-D Try plugging yours into the Main and see what happens. :)

Module Module1
Sub Main()
Dim s As String = ""
Console.WriteLine("--- Kilobytes ---")
s = FormattedFileSize(1023)
Console.WriteLine("1023 > " & s)
s = FormattedFileSize(1024)
Console.WriteLine("1024 > " & s)
s = FormattedFileSize(1025)
Console.WriteLine("1025 > " & s)

  Console.WriteLine("--- Megabytes ---")
  s = FormattedFileSize(1048575)
  Console.WriteLine("1048575 > " & s)
  s = FormattedFileSize(1048576)
  Console.WriteLine("1048576 > " & s)
  s = FormattedFileSize(1048577)
  Console.WriteLine("1048577 > " & s)
  s = FormattedFileSize(1048576 \* 2)
  Console.WriteLine("1048577 \* 2 > " & s)

  Console.WriteLine("--- Gigabytes ---")
  s = FormattedFileSize(1048576 \* 1024)
  Console.WriteLine("1048576 \* 1024 > " & s)

  Console.ReadLine()

End Sub

Public Function FormattedFileSize(ByVal sizeInBytes As Long) As String
Dim suffix() As String = New String() {"", "KB", "MB", "GB", "XX"}
Dim retVal As String = "Oops"
Dim units As Double = sizeInBytes
Dim index As Integer = 0
Do
units = units / 1024.0
index += 1
Loop While units >= 1024.0

  retVal = Format(units, "###,###,##0.000") + suffix(index)
  Return retVal

End Function

End Module

PS you just need to change the name of the function calls e.g. use s = BytesFormatting(1024)

Regards David R --------------------------------------------------------------- "Every program eventually becomes rococo, and then rubble." - Alan Perlis The only valid measurement of code quality: WTFs/minute.

[Dayekh]

Thank you all for your input! I certainly was happy that this issue had a lot of interest. "i would hope that anybody who is working in IT knows the relationships between bits bytes k, m, g, t.....and on and on." -- knowing the relationship between bytes, KB, MB, etc.. was irrelevant as I was asking if there was a class/method that automatically did the conversions in VB.Net. And yes, I know the relationship between them :P "I think he meant: no need for me to test it, just publish and wait a while." -- Yea I'm sure all programmers are perfect testers of THEIR own code. I did some testing, but it obviously wasn't good enough. I suppose that's what learning is.. no? "What if file is exactly 1024 or 1048576 bytes?" -- Good point! I was swamped with work that I overlooked that fault. Thank you. "But there's even worse when you look at it more closely e.g. a file of 1023 bytes returns 1,023.00KB." -- Another good point. I need to address all eventualities more closely! "I decide to benefit and wrote something that does work." -- Thank you. I will work through that code. Thanks again all! This made my day.

[Luc Pattyn]

You have some IndexOutOfRange problems... As a little VB exercise, here an alternative, spanning a larger range of values; the result is slightly different, notation is float or integer as appropriate:

Private Sub Button1\_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim pow As Long = 1
    For i = 0 To 63
        Dim fraction As Long = pow \\ 32
        If fraction < 1 Then fraction = 1
        test(-pow)
        test(pow - fraction)
        test(pow)
        test(pow + fraction)
        If pow >= &H4000000000000000 Then Exit For
        pow = 2 \* pow
    Next
End Sub

Public Sub test(ByVal value As Long)
    Dim s As String
    s = FormattedFileSize(value)
    Console.WriteLine(value.ToString().PadLeft(20) & " = " & value.ToString("X16") & " = " & s & "B")
End Sub

Public Function FormattedFileSize(ByVal sizeInBytes As Long) As String
    Dim negative As Boolean = False
    Dim result As String
    Dim value As Long = sizeInBytes
    Dim remainder As Long = 0
    Dim suffixIndex As Integer
    If value < 0 Then
        negative = True
        value = -value
    End If
    For suffixIndex = 0 To 20
        If value <= 1023 Then Exit For
        remainder = value Mod 1024
        value = value \\ 1024
    Next
    If remainder > 0 Then
        Dim d As Double = value + remainder / 1024
        result = d.ToString("F3")
    Else
        result = value.ToString()
    End If
    If suffixIndex > 0 Then result = result & " KMGTPEZY"(suffixIndex)
    If negative Then result = "-" & result
    Return result
End Function

Homework: find and fix the value(s) that still fail. :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

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[riced]

I knew it would error for extremely large sizes and failed on negatives so here's a fix. (Not sure the negatives a right.)

Public Function FormattedFileSize(ByVal sizeInBytes As Long) As String
Dim suffix() As String = New String() {"Oops", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB", "XX"}
Dim units As Double = Math.Abs(sizeInBytes) 'Fudge to deal with negatives. Should it error with neg file size?
Dim index As Integer = 0

  Do
     units = units / 1024.0
     index += 1
  Loop While units >= 1024.0

  Return Format(units, "###,###,##0.000") + suffix(index)

End Function

I've not done homework for years. :)

Regards David R --------------------------------------------------------------- "Every program eventually becomes rococo, and then rubble." - Alan Perlis The only valid measurement of code quality: WTFs/minute.

[Paul Conrad]

Richard MacCutchan wrote:

once heard one of our IT help desk reps ask a colleague "What exactly is hexadecimal?"

:omg:

"The clue train passed his station without stopping." - John Simmons / outlaw programmer "Real programmers just throw a bunch of 1s and 0s at the computer to see what sticks" - Pete O'Hanlon "Not only do you continue to babble nonsense, you can't even correctly remember the nonsense you babbled just minutes ago." - Rob Graham