Creating a byte array from a stream

Question

What is the prefered method for creating a byte array from an input stream    Here is my current solution with  NET 3 5    Stream s  byte   b   using  BinaryReader br   new BinaryReader s         b   br ReadBytes  int s Length       Is it still a better idea to read and write chunks of the stream

User · Answer

Just want to point out that in case you have a MemoryStream you already have memorystream.ToArray() for that.

Also, if you are dealing with streams of unknown or different subtypes and you can receive a MemoryStream, you can relay on said method for those cases and still use the accepted answer for the others, like this:

public static byte[] StreamToByteArray(Stream stream)
{
    if (stream is MemoryStream)
    {
        return ((MemoryStream)stream).ToArray();                
    }
    else
    {
        // Jon Skeet's accepted answer 
        return ReadFully(stream);
    }
}

User · Answer

The one above is ok   but you will encounter data corruption when you send stuff over SMTP  if you need to   I ve altered to something else that will help to correctly send byte for byte     using System  using System IO           private static byte   ReadFully string input                        FileStream sourceFile   new FileStream input  FileMode Open     Open streamer             BinaryReader binReader   new BinaryReader sourceFile               byte   output   new byte sourceFile Length     create byte array of size file             for  long i   0  i  lt  sourceFile Length  i                    output i    binReader ReadByte      read until done             sourceFile Close      dispose streamer             binReader Close      dispose reader             return output

User · Answer

It really depends on whether or not you can trust s Length  For many streams  you just don t know how much data there will be  In such cases - and before  NET 4 - I d use code like this   public static byte   ReadFully Stream input        byte   buffer   new byte 16 1024       using  MemoryStream ms   new MemoryStream                  int read          while   read   input Read buffer  0  buffer Length    gt  0                        ms Write buffer  0  read                     return ms ToArray              With  NET 4 and above  I d use Stream CopyTo  which is basically equivalent to the loop in my code - create the MemoryStream  call stream CopyTo ms  and then return ms ToArray    Job done   I should perhaps explain why my answer is longer than the others  Stream Read doesn t guarantee that it will read everything it s asked for  If you re reading from a network stream  for example  it may read one packet s worth and then return  even if there will be more data soon  BinaryReader Read will keep going until the end of the stream or your specified size  but you still have to know the size to start with   The above method will keep reading  and copying into a MemoryStream  until it runs out of data  It then asks the MemoryStream to return a copy of the data in an array  If you know the size to start with - or think you know the size  without being sure - you can construct the MemoryStream to be that size to start with  Likewise you can put a check at the end  and if the length of the stream is the same size as the buffer  returned by MemoryStream GetBuffer  then you can just return the buffer  So the above code isn t quite optimised  but will at least be correct  It doesn t assume any responsibility for closing the stream - the caller should do that   See this article for more info  and an alternative implementation

User · Answer

You can even make it fancier with extensions   namespace Foo       public static class Extensions               public static byte   ToByteArray this Stream stream                        using  stream                                using  MemoryStream memStream   new MemoryStream                                           stream CopyTo memStream                        return memStream ToArray                                                        And then call it as a regular method   byte   arr   someStream ToByteArray

User · Answer

While Jon s answer is correct  he is rewriting code that already exists in CopyTo  So for  Net 4 use Sandip s solution  but for previous version of  Net use Jon s answer  Sandip s code would be improved by use of  using  as exceptions in CopyTo are  in many situations  quite likely and would leave the MemoryStream not disposed   public static byte   ReadFully Stream input        using  MemoryStream ms   new MemoryStream                  input CopyTo ms           return ms ToArray

User · Answer

In namespace RestSharp Extensions there is method ReadAsBytes  Inside this method is used MemoryStream and there is the same code like in some examples on this page but when you are using RestSharp this is easiest way   using RestSharp Extensions  var byteArray   inputStream ReadAsBytes

User · Answer

This is the function which I am using  tested and worked well  please bear in mind that  input  should not be null and  input position  should reset to  0  before reading otherwise it will break the read loop and nothing will read to convert to array       public static byte   StreamToByteArray Stream input                if  input    null              return null          byte   buffer   new byte 16   1024           input Position   0          using  MemoryStream ms   new MemoryStream                          int read              while   read   input Read buffer  0  buffer Length    gt  0                                ms Write buffer  0  read                             byte   temp   ms ToArray                 return temp

User · Answer

It really depends on whether or not you can trust s Length  For many streams  you just don t know how much data there will be  In such cases - and before  NET 4 - I d use code like this   public static byte   ReadFully Stream input        byte   buffer   new byte 16 1024       using  MemoryStream ms   new MemoryStream                  int read          while   read   input Read buffer  0  buffer Length    gt  0                        ms Write buffer  0  read                     return ms ToArray              With  NET 4 and above  I d use Stream CopyTo  which is basically equivalent to the loop in my code - create the MemoryStream  call stream CopyTo ms  and then return ms ToArray    Job done   I should perhaps explain why my answer is longer than the others  Stream Read doesn t guarantee that it will read everything it s asked for  If you re reading from a network stream  for example  it may read one packet s worth and then return  even if there will be more data soon  BinaryReader Read will keep going until the end of the stream or your specified size  but you still have to know the size to start with   The above method will keep reading  and copying into a MemoryStream  until it runs out of data  It then asks the MemoryStream to return a copy of the data in an array  If you know the size to start with - or think you know the size  without being sure - you can construct the MemoryStream to be that size to start with  Likewise you can put a check at the end  and if the length of the stream is the same size as the buffer  returned by MemoryStream GetBuffer  then you can just return the buffer  So the above code isn t quite optimised  but will at least be correct  It doesn t assume any responsibility for closing the stream - the caller should do that   See this article for more info  and an alternative implementation

User · Answer

I get a compile time error with Bob s  i e  the questioner s  code  Stream Length is a long whereas BinaryReader ReadBytes takes an integer parameter  In my case  I do not expect to be dealing with Streams large enough to require long precision  so I use the following   Stream s  byte   b   if  s Length  gt  int MaxValue      throw new Exception  This stream is larger than the conversion algorithm can currently handle        using  var br   new BinaryReader s       b   br ReadBytes  int s Length

User · Answer

just my couple cents    the practice that I often use is to organize the methods like this as a custom helper  public static class StreamHelpers       public static byte   ReadFully this Stream input                using  MemoryStream ms   new MemoryStream                          input CopyTo ms               return ms ToArray                        add namespace to the config file and use it anywhere you wish

User · Answer

public static byte   ToByteArray Stream stream                if  stream is MemoryStream                        return   MemoryStream stream  ToArray                      else                       byte   buffer   new byte 16   1024               using  MemoryStream ms   new MemoryStream                                  int read                  while   read   stream Read buffer  0  buffer Length    gt  0                                        ms Write buffer  0  read                                     return ms ToArray

User · Answer

You can simply use ToArray   method of MemoryStream class  for ex-  MemoryStream ms    MemoryStream dataInStream  byte   imageBytes   ms ToArray

User · Answer

While Jon s answer is correct  he is rewriting code that already exists in CopyTo  So for  Net 4 use Sandip s solution  but for previous version of  Net use Jon s answer  Sandip s code would be improved by use of  using  as exceptions in CopyTo are  in many situations  quite likely and would leave the MemoryStream not disposed   public static byte   ReadFully Stream input        using  MemoryStream ms   new MemoryStream                  input CopyTo ms           return ms ToArray

User · Answer

The one above is ok   but you will encounter data corruption when you send stuff over SMTP  if you need to   I ve altered to something else that will help to correctly send byte for byte     using System  using System IO           private static byte   ReadFully string input                        FileStream sourceFile   new FileStream input  FileMode Open     Open streamer             BinaryReader binReader   new BinaryReader sourceFile               byte   output   new byte sourceFile Length     create byte array of size file             for  long i   0  i  lt  sourceFile Length  i                    output i    binReader ReadByte      read until done             sourceFile Close      dispose streamer             binReader Close      dispose reader             return output

User · Answer

It really depends on whether or not you can trust s Length  For many streams  you just don t know how much data there will be  In such cases - and before  NET 4 - I d use code like this   public static byte   ReadFully Stream input        byte   buffer   new byte 16 1024       using  MemoryStream ms   new MemoryStream                  int read          while   read   input Read buffer  0  buffer Length    gt  0                        ms Write buffer  0  read                     return ms ToArray              With  NET 4 and above  I d use Stream CopyTo  which is basically equivalent to the loop in my code - create the MemoryStream  call stream CopyTo ms  and then return ms ToArray    Job done   I should perhaps explain why my answer is longer than the others  Stream Read doesn t guarantee that it will read everything it s asked for  If you re reading from a network stream  for example  it may read one packet s worth and then return  even if there will be more data soon  BinaryReader Read will keep going until the end of the stream or your specified size  but you still have to know the size to start with   The above method will keep reading  and copying into a MemoryStream  until it runs out of data  It then asks the MemoryStream to return a copy of the data in an array  If you know the size to start with - or think you know the size  without being sure - you can construct the MemoryStream to be that size to start with  Likewise you can put a check at the end  and if the length of the stream is the same size as the buffer  returned by MemoryStream GetBuffer  then you can just return the buffer  So the above code isn t quite optimised  but will at least be correct  It doesn t assume any responsibility for closing the stream - the caller should do that   See this article for more info  and an alternative implementation

User · Answer

Create a helper class and reference it anywhere you wish to use it    public static class StreamHelpers       public static byte   ReadFully this Stream input                using  MemoryStream ms   new MemoryStream                          input CopyTo ms               return ms ToArray

User · Answer

This is the function which I am using  tested and worked well  please bear in mind that  input  should not be null and  input position  should reset to  0  before reading otherwise it will break the read loop and nothing will read to convert to array       public static byte   StreamToByteArray Stream input                if  input    null              return null          byte   buffer   new byte 16   1024           input Position   0          using  MemoryStream ms   new MemoryStream                          int read              while   read   input Read buffer  0  buffer Length    gt  0                                ms Write buffer  0  read                             byte   temp   ms ToArray                 return temp

User · Answer

You can use this extension method   public static class StreamExtensions       public static byte   ToByteArray this Stream stream                var bytes   new List lt byte gt              int b          while   b   stream ReadByte       -1              bytes Add  byte b            return bytes ToArray

User · Answer

In case anyone likes it  here is a  NET 4  only solution formed as an extension method without the needless Dispose call on the MemoryStream   This is a hopelessly trivial optimization  but it is worth noting that failing to Dispose a MemoryStream is not a real failure   public static class StreamHelpers       public static byte   ReadFully this Stream input                var ms   new MemoryStream            input CopyTo ms           return ms ToArray

User · Answer

You can use this extension method   public static class StreamExtensions       public static byte   ToByteArray this Stream stream                var bytes   new List lt byte gt              int b          while   b   stream ReadByte       -1              bytes Add  byte b            return bytes ToArray

User · Answer

public static byte   ToByteArray Stream stream                if  stream is MemoryStream                        return   MemoryStream stream  ToArray                      else                       byte   buffer   new byte 16   1024               using  MemoryStream ms   new MemoryStream                                  int read                  while   read   stream Read buffer  0  buffer Length    gt  0                                        ms Write buffer  0  read                                     return ms ToArray

User · Answer

Create a helper class and reference it anywhere you wish to use it    public static class StreamHelpers       public static byte   ReadFully this Stream input                using  MemoryStream ms   new MemoryStream                          input CopyTo ms               return ms ToArray

User · Answer

In namespace RestSharp Extensions there is method ReadAsBytes  Inside this method is used MemoryStream and there is the same code like in some examples on this page but when you are using RestSharp this is easiest way   using RestSharp Extensions  var byteArray   inputStream ReadAsBytes

User · Answer

MemoryStream ms   new MemoryStream    file PostedFile InputStream CopyTo ms   var byts   ms ToArray    ms Dispose

User · Answer

MemoryStream ms   new MemoryStream    file PostedFile InputStream CopyTo ms   var byts   ms ToArray    ms Dispose

User · Answer

You can even make it fancier with extensions   namespace Foo       public static class Extensions               public static byte   ToByteArray this Stream stream                        using  stream                                using  MemoryStream memStream   new MemoryStream                                           stream CopyTo memStream                        return memStream ToArray                                                        And then call it as a regular method   byte   arr   someStream ToByteArray

User · Answer

I get a compile time error with Bob s  i e  the questioner s  code  Stream Length is a long whereas BinaryReader ReadBytes takes an integer parameter  In my case  I do not expect to be dealing with Streams large enough to require long precision  so I use the following   Stream s  byte   b   if  s Length  gt  int MaxValue      throw new Exception  This stream is larger than the conversion algorithm can currently handle        using  var br   new BinaryReader s       b   br ReadBytes  int s Length

User · Answer

i was able to make it work on a single line   byte    byteArr    MemoryStream localStream  ToArray      as clarified by johnnyRose  Above code will only work for MemoryStream

User · Answer

just my couple cents    the practice that I often use is to organize the methods like this as a custom helper  public static class StreamHelpers       public static byte   ReadFully this Stream input                using  MemoryStream ms   new MemoryStream                          input CopyTo ms               return ms ToArray                        add namespace to the config file and use it anywhere you wish

User · Answer

You can simply use ToArray   method of MemoryStream class  for ex-  MemoryStream ms    MemoryStream dataInStream  byte   imageBytes   ms ToArray

User · Answer

In case anyone likes it  here is a  NET 4  only solution formed as an extension method without the needless Dispose call on the MemoryStream   This is a hopelessly trivial optimization  but it is worth noting that failing to Dispose a MemoryStream is not a real failure   public static class StreamHelpers       public static byte   ReadFully this Stream input                var ms   new MemoryStream            input CopyTo ms           return ms ToArray

User · Answer

i was able to make it work on a single line   byte    byteArr    MemoryStream localStream  ToArray      as clarified by johnnyRose  Above code will only work for MemoryStream

User · Answer

Just want to point out that in case you have a MemoryStream you already have memorystream.ToArray() for that.

Also, if you are dealing with streams of unknown or different subtypes and you can receive a MemoryStream, you can relay on said method for those cases and still use the accepted answer for the others, like this:

public static byte[] StreamToByteArray(Stream stream)
{
    if (stream is MemoryStream)
    {
        return ((MemoryStream)stream).ToArray();                
    }
    else
    {
        // Jon Skeet's accepted answer 
        return ReadFully(stream);
    }
}

User · Answer

It really depends on whether or not you can trust s Length  For many streams  you just don t know how much data there will be  In such cases - and before  NET 4 - I d use code like this   public static byte   ReadFully Stream input        byte   buffer   new byte 16 1024       using  MemoryStream ms   new MemoryStream                  int read          while   read   input Read buffer  0  buffer Length    gt  0                        ms Write buffer  0  read                     return ms ToArray              With  NET 4 and above  I d use Stream CopyTo  which is basically equivalent to the loop in my code - create the MemoryStream  call stream CopyTo ms  and then return ms ToArray    Job done   I should perhaps explain why my answer is longer than the others  Stream Read doesn t guarantee that it will read everything it s asked for  If you re reading from a network stream  for example  it may read one packet s worth and then return  even if there will be more data soon  BinaryReader Read will keep going until the end of the stream or your specified size  but you still have to know the size to start with   The above method will keep reading  and copying into a MemoryStream  until it runs out of data  It then asks the MemoryStream to return a copy of the data in an array  If you know the size to start with - or think you know the size  without being sure - you can construct the MemoryStream to be that size to start with  Likewise you can put a check at the end  and if the length of the stream is the same size as the buffer  returned by MemoryStream GetBuffer  then you can just return the buffer  So the above code isn t quite optimised  but will at least be correct  It doesn t assume any responsibility for closing the stream - the caller should do that   See this article for more info  and an alternative implementation

[c#] Creating a byte array from a stream

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