Byte arrays perfromance question

[Nikolay Petrov]

I have a couple of byte arrays.
What is the most efficient way to combine them?
After combining they will go in a network stream.

thanks

[Herfried K. Wagner [MVP]]

"Nikolay Petrov" <jo******@mail. bg> schrieb:

I have a couple of byte arrays.
What is the most efficient way to combine them?
After combining they will go in a network stream.

\\\
Dim a1() As Byte = {1, 2, 3, 4, 5}
Dim a2() As Byte = {6, 7, 8, 9, 10}
Dim a(a1.Length + a2.Length - 1) As Byte
Buffer.BlockCop y(a1, 0, a, 0, a1.Length)
Buffer.BlockCop y(a2, 0, a, a1.Length, a2.Length)
///

Alternatively you can write the two arrays to the stream consecutively.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Cor Ligthert]

Nikolay,

Alternative from Herfrieds method using same sample.
(I find this easier to write)

\\\
Dim a1() As Byte = {1, 2, 3, 4, 5}
Dim a2() As Byte = {6, 7, 8, 9, 10}
Dim a(a1.Length + a2.Length - 1) As Byte
a1.CopyTo(a, 0)
a2.CopyTo(a, a1.Length)
////

I hope this helps,

Cor

[Herfried K. Wagner [MVP]]

Cor,

"Cor Ligthert" <no************ @planet.nl> schrieb:

Alternative from Herfrieds method using same sample.
(I find this easier to write)

\\\
Dim a1() As Byte = {1, 2, 3, 4, 5}
Dim a2() As Byte = {6, 7, 8, 9, 10}
Dim a(a1.Length + a2.Length - 1) As Byte
a1.CopyTo(a, 0)
a2.CopyTo(a, a1.Length)
////

Note that the performance of 'Buffer.BlockCo py' is better than those of
'Array.CopyTo', and the OP asked for a fast solution.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Cor Ligthert]

Herfried,

Note that the performance of 'Buffer.BlockCo py' is better than those of
'Array.CopyTo', and the OP asked for a fast solution.

I thought let me make a sample to show how right Herfried is in his answer,
your sample is almost 0,0015 times faster. You can try it, the sample that
does 100.000.000 loops needs depending on the computer 1 to 5 minutes I
assume. On your fast computer probably less than 2 minutes.

\\\
Public Module My
Sub Main()
Dim a1() As Byte = {1, 2, 3, 4, 5}
Dim a2() As Byte = {6, 7, 8, 9, 10}
Dim a(a1.Length + a2.Length - 1) As Byte
For y As Integer = 0 To 9
Dim steps As Integer = 10000000
Dim test1 As Integer = Environment.Tic kCount
For i As Integer = 0 To steps
Buffer.BlockCop y(a1, 0, a, 0, a1.Length)
Buffer.BlockCop y(a2, 0, a, a1.Length, a2.Length)
Next
test1 = Environment.Tic kCount - 1
Dim test2 As Integer = Environment.Tic kCount
For i As Integer = 0 To steps
a1.CopyTo(a, 0)
a2.CopyTo(a, a1.Length)
Next
test2 = Environment.Tic kCount - 1
Console.Write(" Methode as provided by Herfried = " _
& (1 - test1 / test2).ToString & " faster than from Cor" &
vbCrLf)
Next
End Sub
End Module
Methode as provided by Herfried = 0,0014613291761 3373 faster than from Cor
Methode as provided by Herfried = 0,0014760397359 268 faster than from Cor
Methode as provided by Herfried = 0,0014788083862 9866 faster than from Cor
Methode as provided by Herfried = 0,0014645579206 1673 faster than from Cor
Methode as provided by Herfried = 0,0014618244886 111 faster than from Cor
Methode as provided by Herfried = 0,0014473067397 0261 faster than from Cor
Methode as provided by Herfried = 0,0014622915571 3606 faster than from Cor
Methode as provided by Herfried = 0,0014478182331 6897 faster than from Cor
Methode as provided by Herfried = 0,0014510005590 3713 faster than from Cor
///

You don't mind that I keep it in this newsgroup for the method, which is for
me easier to remember and less characters to write.

:-)

Cor

[Herfried K. Wagner [MVP]]

"Cor Ligthert" <no************ @planet.nl> schrieb:

Note that the performance of 'Buffer.BlockCo py' is better than those of
'Array.CopyTo', and the OP asked for a fast solution.

I thought let me make a sample to show how right Herfried is in his
answer, your sample is almost 0,0015 times faster. You can try it, the
sample that does 100.000.000 loops needs depending on the computer 1 to 5
minutes I assume. On your fast computer probably less than 2 minutes.

I didn't test it and I won't test it. The documentation of 'Buffer' states
that the performance is better than with 'System.Array', and that's why the
'Buffer' class exists:

| 'Buffer' provides methods to copy bytes from one array of
| primitive types to another array of primitive types, get a
| byte from an array, set a byte in an array, and obtain the length
| of an array. This class provides better performance for manipulating
| primitive types than similar methods in the 'System.Array' class.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Stephen Martin]

If you correct your test code you'll find that Herfried's BlockCopy is about
70% to 75% faster.

Line 13: test1 = Environment.Tic kCount - 1
-> test1 = Environment.Tic kCount - test1

Line 19: test2 = Environment.Tic kCount - 1
-> test2 = Environment.Tic kCount - test2
"Cor Ligthert" <no************ @planet.nl> wrote in message
news:%2******** **********@TK2M SFTNGP15.phx.gb l...

Herfried,

Note that the performance of 'Buffer.BlockCo py' is better than those of
'Array.CopyTo', and the OP asked for a fast solution.

I thought let me make a sample to show how right Herfried is in his
answer, your sample is almost 0,0015 times faster. You can try it, the
sample that does 100.000.000 loops needs depending on the computer 1 to 5
minutes I assume. On your fast computer probably less than 2 minutes.

\\\
Public Module My
Sub Main()
Dim a1() As Byte = {1, 2, 3, 4, 5}
Dim a2() As Byte = {6, 7, 8, 9, 10}
Dim a(a1.Length + a2.Length - 1) As Byte
For y As Integer = 0 To 9
Dim steps As Integer = 10000000
Dim test1 As Integer = Environment.Tic kCount
For i As Integer = 0 To steps
Buffer.BlockCop y(a1, 0, a, 0, a1.Length)
Buffer.BlockCop y(a2, 0, a, a1.Length, a2.Length)
Next
test1 = Environment.Tic kCount - 1
Dim test2 As Integer = Environment.Tic kCount
For i As Integer = 0 To steps
a1.CopyTo(a, 0)
a2.CopyTo(a, a1.Length)
Next
test2 = Environment.Tic kCount - 1
Console.Write(" Methode as provided by Herfried = " _
& (1 - test1 / test2).ToString & " faster than from Cor" &
vbCrLf)
Next
End Sub
End Module
Methode as provided by Herfried = 0,0014613291761 3373 faster than from Cor
Methode as provided by Herfried = 0,0014760397359 268 faster than from Cor
Methode as provided by Herfried = 0,0014788083862 9866 faster than from Cor
Methode as provided by Herfried = 0,0014645579206 1673 faster than from Cor
Methode as provided by Herfried = 0,0014618244886 111 faster than from Cor
Methode as provided by Herfried = 0,0014473067397 0261 faster than from Cor
Methode as provided by Herfried = 0,0014622915571 3606 faster than from Cor
Methode as provided by Herfried = 0,0014478182331 6897 faster than from Cor
Methode as provided by Herfried = 0,0014510005590 3713 faster than from Cor
///

You don't mind that I keep it in this newsgroup for the method, which is
for me easier to remember and less characters to write.

:-)

Cor

[Herfried K. Wagner [MVP]]

"Stephen Martin" <sm*****@remove this.emsoft.and this.ca> schrieb:

If you correct your test code you'll find that Herfried's BlockCopy is
about 70% to 75% faster.

Line 13: test1 = Environment.Tic kCount - 1
-> test1 = Environment.Tic kCount - test1

Line 19: test2 = Environment.Tic kCount - 1
-> test2 = Environment.Tic kCount - test2

Good catch!

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Cor Ligthert]

Stephen,

Thanks I did not see it, and I knew that can not be so thight together.I
think that I have ten times overlooked this part, because there I know I
make often an error.

Just blind for the code

Cor

Methode as provided by Herfried = 0,7252076209086 47 faster than from Cor
Methode as provided by Herfried = 0,71475 faster than from Cor
Methode as provided by Herfried = 0,7172619047619 05 faster than from Cor
Methode as provided by Herfried = 0,71875 faster than from Cor
Methode as provided by Herfried = 0,7142494284988 57 faster than from Cor
Methode as provided by Herfried = 0,7221234442468 88 faster than from Cor
Methode as provided by Herfried = 0,7221940071102 08 faster than from Cor
Methode as provided by Herfried = 0,7224479431183 34 faster than from Cor
Methode as provided by Herfried = 0,7209895434838 05 faster than from Cor

[Some Guy]

Buffer.BlockCop y = 2.9 secs
CopyTo = 8.2 secs
Array.Copy = 7.5 secs

Enough said.

"Herfried K. Wagner [MVP]" <hi************ ***@gmx.at> wrote in message
news:%2******** ********@TK2MSF TNGP09.phx.gbl. ..

"Stephen Martin" <sm*****@remove this.emsoft.and this.ca> schrieb:

If you correct your test code you'll find that Herfried's BlockCopy is
about 70% to 75% faster.

Line 13: test1 = Environment.Tic kCount - 1
-> test1 = Environment.Tic kCount - test1

Line 19: test2 = Environment.Tic kCount - 1
-> test2 = Environment.Tic kCount - test2

Good catch!

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>