Copyright	(c) Mattias Jakobsson 2015
License	GPL-3
Maintainer	mjakob422@gmail.com
Stability	unstable
Portability	portable
Safe Haskell	Safe
Language	Haskell2010

Data.Grib.Raw.Handle

Contents

The GRIB Handle
- Operations on raw messages
The GRIB Multi Field Handle
Utilities

Description

The grib_handle is the structure giving access to parsed grib values by keys.

Most of the documentation herein was copied from the official documentation of grib_api.

Synopsis

The GRIB Handle

newtype GribHandle Source

Grib handle, structure giving access to parsed grib values by keys.

Constructors

GribHandle (ForeignPtr GribHandle)

Instances

Eq GribHandle Source
Show GribHandle Source

gribHandleNewFromFile :: GribContext -> CFilePtr -> IO GribHandle Source

Create a handle from a file resource.

The file is read until a message is found. The message is then copied.

gribHandleNewFromTemplate :: GribContext -> String -> IO GribHandle Source

This function has been deprecated in GRIB API.

Create a handle from a read_only template resource.

The message is copied at the creation of the handle.

This operation may fail with:

NullPtrReturned if the resource is invalid or a problem is encountered.

gribHandleNewFromSamples Source

Arguments

:: GribContext	the context from which the handle will be created (NULL for default context)
-> String	the resource name
-> IO GribHandle

Create a handle from a message contained in a samples directory.

The message is copied at the creation of the handle.

This operation may fail with:

NullPtrReturned if the resource is invalid or a problem is encountered.

gribHandleClone :: GribHandle -> IO GribHandle Source

Clone an existing handle using the context of the original handle.

The message is copied and reparsed.

This operation may fail with:

NullPtrReturned if the message is invalid or a problem is encountered.

gribWriteMessage :: GribHandle -> FilePath -> String -> IO () Source

Write a coded message to a file given its name and the C file mode string, in that order.

withGribHandle :: GribHandle -> (Ptr GribHandle -> IO b) -> IO b Source

Operations on raw messages

gribGetMessage :: GribHandle -> IO (Message, Int) Source

Getting the message attached to a handle.

gribGetMessageCopy Source

Arguments

:: GribHandle	the grib handle to which the buffer should be returned
-> Message	the pointer to the data buffer to be filled
-> Int	the size in number of bytes of the allocated empty message
-> IO (Message, Int)	an IO action that will return the pointer to the data buffer and the number of bytes retrieved

Getting a copy of the message attached to a handle.

This operation may fail with:

isGribException GribBufferTooSmall if the allocated message is too small.

gribHandleNewFromMessage :: GribContext -> Message -> Int -> IO GribHandle Source

Create a handle from a user message in memory.

The message will not be freed at the end. The message will be copied as soon as a modification is needed.

This operation may fail with:

NullPtrReturned if the message is invalid or a problem is encountered.

WARNING! This method does not handle a message of zero length gracefully.

gribHandleNewFromMessageCopy :: GribContext -> Message -> Int -> IO GribHandle Source

Create a handle from a user message.

The message is copied and will be freed with the handle.

This operation may fail with:

NullPtrReturned if the message is invalid or a problem is encountered.

gribHandleNewFromMultiMessage :: GribContext -> Message -> Int -> IO (GribHandle, Message, Int) Source

Create a handle from a user message in memory.

The message will not be freed at the end. The message will be copied as soon as a modification is needed. This function works also with multi field messages.