[Gambas-user] My quest for efficiency

[Caveat]

Something is horribly wrong, or you're running on a 286 :-)

I just tested here, and the program runs on a 51 MB test file in about 5 
seconds.

Some reasonably well commented code for you...

Public Sub Main()

   Dim inFile, outFile As File
   Dim buff As New Byte[1024]
   Dim idx, remBytes, readSize As Integer

   ' CHANGE THIS to your input file
   inFile = Open "/home/caveat/Downloads/mytestfile" For Read

   ' CHANGE THIS to your output file
   outFile = Open "/home/caveat/Downloads/mytestfile.out2" For Create

   ' Remaining bytes starts as the total length of the file
   remBytes = Lof(inFile)

   ' Until we reach the end of the input file...guess you could instead 
check on remBytes...
   While Not Eof(inFile)
     If remBytes > buff.length Then
       ' Limit reading to the size of our buffer (the Byte[])
       readSize = buff.length
     Else
       ' Only read the bytes we have left into our buffer (the Byte[])
       readSize = remBytes
     Endif
     ' Read from the input file into our buffer, starting at offset 0 in 
the buffer
     buff.Read(inFile, 0, readSize)
     ' Update the number of bytes remaining...
     remBytes = remBytes - readSize
     ' Run round each byte in our buffer
     For idx = 0 To buff.length - 1
       ' Dunno if you need any conditions, I check for > 30 as I can put 
newlines in the file to make it more readable for testing
       If buff[idx] > 30 Then
         ' This is the 'trick' you need to apply... subtract 11 from 
every byte in the file
         ' Not sure how you deal with edge cases... if you have a byte 
of 5, is your result then 250?
         buff[idx] = buff[idx] - 11
       Endif
     Next
     ' Write the whole buffer out to the output file
     buff.Write(outFile, 0, readSize)
   Wend

   Close #inFile
   Close #outFile

End


Kind regards,
Caveat

On 15-07-17 21:24, Benoît Minisini via Gambas-user wrote:
> Le 15/07/2017 à 20:49, Tony Morehen a écrit :
>> Did you try Benoit's suggestion:
>>
>> Public Sub Main()
>>
>>    Dim sIn as String
>>    Dim sOut as String
>>
>>    sIn = File.Load("/home/fernando/temp/deah001.dhn")
>>    sOut = Add11(sIn)
>>    File.Save("/home/fernando/temp/deah001.11Added.dhn", sOut)
>>
>> End
>>
>> Public Sub Add11(InputString as String) as String
>>    Dim bArray As Byte[]
>>    Dim String11 As String
>>    Dim i As Integer
>>
>>    bArray = Byte[].FromString(InputString)
>>    For i = 0 To bArray.Max
>>      bArray[i] += 11
>>    Next
>>   Return bArray.ToString
>> End
>>
>>
>
> Just a remark:
>
> You don't have to use Byte[].FromString.
>
> You can use the Bute[].Read() method instead, to load the file 
> directly into the array. You save an intermediate string that way.
>
> Regards,
>