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
[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: [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
[Haskell-cafe] Basic Binary IO
Hi all! Todayi 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 editthe 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
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
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
