read each chunk of 256 bytes from a 32k file and then add the total value of each byte's decimal value. This will be some huge number which then needs to be converted to hex (Hex(number)and then truncate down to the LSB (I.E. 7F{4B}) and then convert the truncated byte (4B) back to a decimal (Num = Val("&H" & Num).
View 2 RepliesSay I have a 5 GB file. I want to split it in the following way.
First 100 MB is on the file
The rest go some reserve file
I do not want to use readalllines kind of function because it's too slow for large files.
I do not want to read the whole file to the memory. I want the program to handle only a medium chunk of data at a time.
I created a text file contains 4 bytes of data
AABBCCDD
I just want to read the first 2 bytes (AABB) to execute it with my program.
Then I'll need to read the last 2 bytes (CCDD) for another computer routines
Problem: Using the sub routing below, when adding a value to another value the results eventually change from 2-decimal places to multiple decimal places.Basically, the amount stored should always only be 2 decimal places, because the values passed in are always 2 decimal places. Output from calling the sub routine multiple times.
Running total = 329430.75
New Withheld Amount = 710.79
Running total = 330141.54
[code]....
As a workaround, I have a new routine that uses a custom round function to properly store only 2 decimal places - as the VB round function does not perform the type of rounding desired.I understand that we are removing the value from the dictionary and adding it back..
Dim sum As Byte
Dim Trans_Array(_64K, 2) As Byte
Const _64K As Integer = 65536
sum = 0
For i = 0 To 15
BinaryStream.Write(Trans_Array(Address + i, RIGHT_FILE))
sum = (Convert.ToByte(sum + Trans_Array(Address + i, RIGHT_FILE)))
Next
I can't figure out how to calculate the checksum of the bytes from array.
does visual basic have any function to allocate a memory by specfying the size of it? I just want to experiment with it, like see what happens when i allocate 2GB of memory on my p3 MHz 512MB ram box =) I know obviously it will crash or have high page file access.
View 8 RepliesIs there any way we could get directly say the 1000 characters after the first 5000 characters, skipping everything before that after sending in an HTTP request to an HTTPS page using either GET or POST in VB.NET? The reason why I ask this question is because in one of the webpage I am trying the get through my program, the website is sending response data in chunks with the first chunk containing some javascript garbage that I have no interest in, the only data I care is in the second chunk and
how to get the second chunk after receiving the first one since it is within the same HTTP request.It would save some time and Internet traffic if I can skip the first chunk that I do not need.Is that possible or I am just day dreaming?
ADDED: Here is how a typical header of the response I am getting from the webpage I am trying to get:
Date: Mon, 20 Jun 2011 13:21:56 GMT
Set-Cookie: JSESSIONID=1AF1AF9EF936E1CB2FA85B750EDC67C4; Path=****some path******; Secure
Content-Type: text/html; charset=ISO-8859-1[code].....
Not sure if that helps, but as you can see, the chunk size is not visible to me, there is no "Trailer" in the header as well.
I am working on a program where specific strings are being read from a file and displayed in a listview. Some of the strings represent money values though the file has no decimal points. I would like to add a decimal point before the last 2 digits of prices, quantities, and freights when displayed in the listview (not add two decimal places but actually insert the decimal point into the string). I would like to be able to keep most of the code I already have though, and I have no clue how to accomplish this. Here is the code I am using to fill the listview:
VB2010
Public Class Form1
Dim dates1() As String[code].......
What is the cleanest, most readable way to String.Format a decimal with the following criteria
start with a sign symbol (+ or -)
a fixed number of fraction digits
no decimal separator
right aligned
pre-padded with "0"'s
I am trying to do a simple summary of table data using a LINQ query.a regular SQL Query looks like:[code]This query works fine and returns the correct results.[code]This LINQ query returns the incorrect results some of the time. Off by .01 in most cases.The "value" column is of type Numeric (12,2) in the database.Now when I show the values from the Sum in a msgbox I get extra precision and thus incorrect results as my end result because of rounding.For example I get 835.18 + 54.62 = 889.80960 from the above LINQ query.I am running Visual Studio 2008 9.0.30729.1 SP on Vista 64Bit with .NET 3.5 SP1.
View 3 RepliesI want it to do is that you input a string, then you select an algorithm (Theres only going to be one RijnDael) then you input a key, then the Initialization Vector comes from "txtIV.text" then you select the key bytes and the block bytes from the numeric up/down, then you either encrypt or decrypt.
View 1 RepliesOk i am having some issues designing a base-class to handle generics.Caveat is i need to restrict the type put in as a Numeric type, specifically Int16, Int32, or Int64 (Short or Long).I know you can do Of T as {Structure} but i dont want to select the key bytes and the block bytes from the numeric up/down.
View 2 Repliesthe first is validating numeric input in a textbox to make sure it's got two decimal places. I think this should be really simple, but I'm totally missing it.The second is adding an extra summary line to a listview. I have it working with all the data required, but I need to add an extra line at the end showing some totals. How do I do this?
View 10 RepliesI keep getting a ProtocolViolationException "Bytes to be written to the stream exceed the Content-Length bytes size specified." on the following code.I've tried setting Content-Length numerous ways with no success.
Dim url = "https://domain.com"
Dim req As WebRequest = WebRequest.Create(url)
req.Method = "POST"
req.ContentType = "application/xml"
[Code]...
What exactly does this line do?
i = stream.Read(bytes, 0, bytes.Length)
Does it read the entire message string sent by the client? I have a line to write to the stream later in the code and that does not seem to be sending anything back to the client, although the code around is excuting.
i = stream.Read(bytes, 0, bytes.Length)
While (i <> 0)
Try
' Translate data bytes to a ASCII string.
[code].....
I've been trying for a long time to create a sorted table of values in a particularly specific way, and I seem to be running into a wall in .NET's file operations. The premise is this - I'm creating a table of values which are being stored as [1 Byte][2 Bytes][3 Bytes]. The location within the file is a value that relates to these three stored values, and so I'm attempting to seek to a specific position in the file, write the 6 bytes into that position, and repeat. There are literally billions of these values, and the total file size is over 100 GB.
Now, I've tried multiple methods to do this, but every single time, it decides it needs to rewrite the ENTIRE FILE every time any change is made. This results in every one of these billions of iterations taking a good 15 minutes, making the task literally impossible. I'm using .NET 4, and I've attempted to use Text, Binary, and Random Access to get it not to rewrite the entire file every edit, but it simply will not obey.
So my question boils down to this: How do I edit specific bytes in a file without writing more than just those bytes? The entire file has been pre-created to the precise size required, and no bytes will be added or deleted in the process. I simply need to overwrite the bytes that already exist.
how to read bytes from a file... but is it possible to read each individual bit, one at a time?
View 1 RepliesIs it possible to change few bytes in a file to make unreadable or is it necessary to change each single byte?
View 1 RepliesI'm trying to edit the bytes in a file. Using this code:
Dim stream As Stream = File.Open("file.exe", FileMode.Open)
stream.Write(File.ReadAllBytes("srcfl.exe"), "0446335", "srcfl.exe".Length)
I've got a web app where I'm trying to validate that an uploaded file is .PDF. I can't use ContentType because if the user renames the file to have a ".PDF" extension, the browser reports the MIME type to be ".PDF" even if it isn't.
I understand that one way to "validate" that a file is a PDF file is to look at the first four bytes, which should always be "%PDF". How do I open and read the first four bytes of a file in VB.NET to see whether or not they are equal to "%PDF"?
Probably missing something silly here, Her eis what my display looks like Sending image...(401303) I would prefer it displays as Sending image...(391 kb)
[Code]...
I'm trying to open an existent file save a bytes in the start of it to later read them.
How can I do that? Because the "&" operand isn't working fo this type of data.
I'm using Encoding.UTF8.GetBytes("text") to convert info to bytes and then add them.
I've been using the following code to download a text file from the web. It only downloads the first 100,000 bytes of the file which is no good if the file is big. The size of the file I'm downloading can vary from day to day, so I need to be able to download a text file of any size.
Dim wr As HttpWebRequest = CType(WebRequest.Create("http://sooty.postalgroup.co.uk/tempmac/nat-import.txt"), HttpWebRequest)
Dim ws As HttpWebResponse = CType(wr.GetResponse(), HttpWebResponse)
[Code].....
[Code]...
How can i return the value? using bytes?
I have an old fashion Database with several random access files and I need to import the data to a new Sql Server dababase the data. There are tables with 6 Bytes floating numbers fields and we have no Number data type with that length in VB. I tried and tried and... and can't find. I found this code in the ERP folder, is AlphaBasic. It use an envoirement namend A-shell from Microsabio .
[Code]...
I want to replace some bytes from a binary file .[code]...
If the value of the textbox is too short I want to replace the remaining bytes for a new value "0"
I am using the following code to write and empty (dummy) file to take up the remaining space on a device.RemSpace is a Public Variable declared as Long I have a function that gets the remaining space on the device and stores in the RemSpace variable (in bytes). I have tested with a msgbox to display the result of RemSpace, and it comes back correct (not 0). However, when the following code attempts to create the dummy file, the file is properly created but is only 0 bytes. What am I missing here?
[Code]...
After getting the file name I create a new filestream and load all the bytes from the FileStream into a byte array, now I need to get certain bytes and store them in fields like the second 4 bytes are the time the file was created. When storing these in the variables should I store them as bytes or as string/integers/etc.
Or have I done it completely wrong?
EDIT:Should I be doing this way instead of a filestream?
Dim data() as Byte = File.ReadAllBytes(path1)
I want to open a file and to replace from 2MB to 3MB of it with another 1MB file. Is it possible?
View 5 RepliesI am not so good with buffers and arrays and I dont know how to continue from here:
[Code]...
My intention is to open an image file as bytes, Convert the bytes to a string, send bytes to server and server stores bytes in a database. Then I need to reverse the process and be able to convert the bytes to an image.