Re: [Haskell-cafe] Basic binary IO
Ah, thanks Don, Brandon, I looked at this but neglected to read through and understand the example enough. Thanks for the tips, they're a great help. Don Stewart wrote: jamie.love: bmpHeader = runPut $ do put 'B' put 'M' put (0 :: Int32) put (0 :: Int32) put (14 :: Int32) Yields the lazy bytestring, "BM\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\SO" -- Jamie Love Senior Consultant Aviarc Australia Mobile: +61 400 548 048 This message has been scanned for viruses and dangerous content by MailScanner and is believed to be clean. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Basic binary IO
jamie.love: > Hello all, > > I'm wondering if anyone has a reference to any binary IO and data > conversion tutorials. A good place to start looking is Data.Binary, http://hackage.haskell.org/cgi-bin/hackage-scripts/package/binary > I'm playing around with generating a BMP file in haskell, and am a > little stuck on the "best" way to go about the simple task of creating > the BMP header. The header is > > "BM" + 4 bytes for file size + 4 bytes reserved + 4 bytes for offset > where data begins. > > I have the basis starting off at: > > bmpHeader = runPut $ >[ 0x42, 0x4D ] ++ >[0 , 0, 0, 0] ++ >[0 , 0, 0, 0] ++ >[14 :: Int32] bmpHeader = runPut $ do put 'B' put 'M' put (0 :: Int32) put (0 :: Int32) put (14 :: Int32) Yields the lazy bytestring, "BM\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\NUL\SO" > (where B is Data.ByteString) > > I'm wondering how I can: > > 1/ convert a 32 bit number (Int32, Char32) to 4 Char8 elements Data.Binary.put (x :: Int32) etc. > 2/ rotate bits/bytes in a 32 bit Char32 (or Int32) so they are > explicitly little-endian (I work on a mac powerbook, and it is big-endian) Use the little endian 'put' primitives, putWord32le (fromIntegral (7 :: Int32)) > 3/ convert an Integer or Int type to an Int32 type > > Any pointers or suggestions would be helpful. fromIntegral Data.Binary should support all this nicely, I hope. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Basic binary IO
On Jan 20, 2008, at 2:26 , Jamie Love wrote: I'm wondering if anyone has a reference to any binary IO and data conversion tutorials. You want the binary package: http://hackage.haskell.org/cgi-bin/ hackage-scripts/package/binary-0.4.1 -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED] system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED] electrical and computer engineering, carnegie mellon universityKF8NH ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Basic binary IO
Hello all, I'm wondering if anyone has a reference to any binary IO and data conversion tutorials. I'm playing around with generating a BMP file in haskell, and am a little stuck on the "best" way to go about the simple task of creating the BMP header. The header is "BM" + 4 bytes for file size + 4 bytes reserved + 4 bytes for offset where data begins. I have the basis starting off at: bmpHeader = B.pack $ [ 0x42, 0x4D ] ++ [0 , 0, 0, 0] ++ [0 , 0, 0, 0] ++ [14 :: Int32] (where B is Data.ByteString) I'm wondering how I can: 1/ convert a 32 bit number (Int32, Char32) to 4 Char8 elements 2/ rotate bits/bytes in a 32 bit Char32 (or Int32) so they are explicitly little-endian (I work on a mac powerbook, and it is big-endian) 3/ convert an Integer or Int type to an Int32 type Any pointers or suggestions would be helpful. Thanks -- Jamie Love Senior Consultant Aviarc Australia Mobile: +61 400 548 048 This message has been scanned for viruses and dangerous content by MailScanner and is believed to be clean. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re[2]: [Haskell-cafe] Basic Binary IO
Hello Donald, Thursday, November 2, 2006, 4:31:31 AM, you wrote: >>Just an example, like opening file "somefile" and separating >>it into something that can be edited in the code (like 8 bit >>words) then go to word nr12 and edit the last bit? > http://haskell.org/haskellwiki/Binary_IO > For flat lists of bytes, use Data.ByteString, for structured data, try > NewBinary. you can also use hGetBuf and pointers machinery -- Best regards, Bulatmailto:[EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Basic Binary IO
nuno: > >Hi all! > >Today i was reading System.IO and didn't manage to >understand how it works just by reading it. >I looked the internet for some help on this, but only >"advanced" information is available. >Can anyone show me how to use openBinaryFile ? >Just an example, like opening file "somefile" and separating >it into something that can be edited in the code (like 8 bit >words) then go to word nr12 and edit the last bit? http://haskell.org/haskellwiki/Binary_IO For flat lists of bytes, use Data.ByteString, for structured data, try NewBinary. There are other options too, documented above. openBinaryFile just sets the line ending handling on windows. I don't think it does what you think it does. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Basic Binary IO
Hi all! Today i was reading System.IO and didn't manage to understand how it works just by reading it. I looked the internet for some help on this, but only "advanced" information is available. Can anyone show me how to use openBinaryFile ? Just an example, like opening file "somefile" and separating it into something that can be edited in the code (like 8 bit words) then go to word nr12 and edit the last bit? Thanks! NPSearch from any Web page with powerful protection. Get the FREE Windows Live Toolbar Today! Try it now! ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
