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https://github.com/idris-lang/Idris2.git
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96 lines
3.7 KiB
Idris
96 lines
3.7 KiB
Idris
module System.File.Buffer
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import public System.File.Error
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import System.File.Handle
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import System.File.Meta
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import System.File.Mode
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import System.File.ReadWrite
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import System.File.Support
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import public System.File.Types
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import Data.Buffer
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%default total
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%foreign support "idris2_readBufferData"
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"node:lambda:(f,b,l,m) => require('fs').readSync(f.fd,b,l,m)"
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prim__readBufferData : FilePtr -> Buffer -> (offset : Int) -> (maxbytes : Int) -> PrimIO Int
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%foreign support "idris2_writeBufferData"
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"node:lambda:(f,b,l,m) => require('fs').writeSync(f.fd,b,l,m)"
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prim__writeBufferData : FilePtr -> Buffer -> (offset : Int) -> (size : Int) -> PrimIO Int
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||| Read the data from the file into the given buffer.
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||| @ fh the file handle to read from
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||| @ buf the buffer to read the data into
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||| @ offset the position in buffer to start adding
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||| @ maxbytes the maximum size to read; must not exceed buffer length
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export
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readBufferData : HasIO io => (fh : File) -> (buf : Buffer) ->
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(offset : Int) ->
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(maxbytes : Int) ->
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io (Either FileError Int)
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readBufferData (FHandle h) buf offset max
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= do read <- primIO (prim__readBufferData h buf offset max)
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if read >= 0
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then pure (Right read)
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else pure (Left FileReadError)
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||| Write the data from the buffer to the given `File`. Returns the number
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||| of bytes that have been written upon a write error. Otherwise, it can
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||| be assumed that `size` number of bytes have been written.
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||| (If you do not have a `File` and just want to write to a file at a known
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||| path, you probably want to use `writeBufferToFile`.)
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|||
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||| @ fh the file handle to write to
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||| @ buf the buffer from which to get the data to write
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||| @ offset the position in buffer to write from
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||| @ size the number of bytes to write; must not exceed buffer length
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export
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writeBufferData : HasIO io => (fh : File) -> (buf : Buffer) ->
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(offset : Int) ->
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(size : Int) ->
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io (Either (FileError, Int) ())
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writeBufferData (FHandle h) buf offset size
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= do written <- primIO (prim__writeBufferData h buf offset size)
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if written == size
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then pure (Right ())
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else pure (Left (FileWriteError, written))
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||| Attempt to write the data from the buffer to the file at the specified file
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||| name. Returns the number of bytes that have been written upon a write error.
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||| Otherwise, it can be assumed that `size` number of bytes have been written.
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|||
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||| @ fn the file name to write to
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||| @ buf the buffer from which to get the data to write
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||| @ size the number of bytes to write; must not exceed buffer length
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export
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writeBufferToFile : HasIO io => (fn : String) -> (buf : Buffer) -> (size : Int) ->
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io (Either (FileError, Int) ())
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writeBufferToFile fn buf size
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= do Right f <- openFile fn WriteTruncate
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| Left err => pure (Left (err, 0))
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Right ok <- writeBufferData f buf 0 size
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| Left err => pure (Left err)
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closeFile f
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pure (Right ok)
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||| Create a new buffer by opening a file and reading its contents into a new
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||| buffer whose size matches the file size.
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||| @ fn the name of the file to read
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export
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createBufferFromFile : HasIO io => (fn : String) -> io (Either FileError Buffer)
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createBufferFromFile fn
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= do Right f <- openFile fn Read
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| Left err => pure (Left err)
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Right size <- fileSize f
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| Left err => pure (Left err)
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Just buf <- newBuffer size
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| Nothing => pure (Left FileReadError)
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Right ok <- readBufferData f buf 0 size
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| Left err => pure (Left err)
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closeFile f
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pure (Right buf)
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