Data.Store.Core

Poke actions are useful for building sequential serializers.

They are actions which write values to bytes into memory specified by a Ptr base. The Applicative and Monad instances make it easy to write serializations, by keeping track of the Offset of the current byte. They allow you to chain Poke action such that subsequent Pokes write into subsequent portions of the output.

Exception thrown while running poke. Note that other types of exceptions could also be thrown. Invocations of fail in the Poke monad causes this exception to be thrown.

PokeExceptions are not expected to occur in ordinary circumstances, and usually indicate a programming error.

Throws a PokeException. These should be avoided when possible, they usually indicate a programming error.

Peek actions are useful for building sequential deserializers.

They are actions which read from memory and construct values from it. The Applicative and Monad instances make it easy to chain these together to get more complicated deserializers. This machinery keeps track of the current Ptr and end-of-buffer Ptr.

A result of a Peek action containing the current Ptr and a return value.

Exception thrown while running peek. Note that other types of exceptions can also be thrown. Invocations of fail in the Poke monad causes this exception to be thrown.

PeekException is thrown when the data being decoded is invalid.

Throws a PeekException.

Throws a PeekException about an attempt to read too many bytes.

Holds a pokeStatePtr, which is passed in to each Poke action. If the package is built with the 'force-alignment' flag, this also has a hidden Ptr field, which is used as scratch space during unaligned writes.

Holds a peekStatePtr, which is passed in to each Peek action. If the package is built with the 'force-alignment' flag, this also has a hidden Ptr field, which is used as scratch space during unaligned reads.

How far into the given Ptr to look

Given a Poke and its length, uses it to fill a ByteString

This function is unsafe because the provided length must exactly match the number of bytes used by the Poke. It will throw PokeException errors when the buffer is under or overshot. However, in the case of overshooting the buffer, memory corruption and segfaults may occur.

Decodes a value from a ByteString, potentially throwing exceptions, and taking a Peek to run. It is an exception to not consume all input.

Decodes a value from a ByteString, potentially throwing exceptions, and taking a Peek to run. It is an exception to not consume all input.

Similar to decodeExWith, but it allows there to be more of the buffer remaining. The Offset of the buffer contents immediately after the decoded value is returned.

Decodes a value from a ByteString, potentially throwing exceptions, and taking a Peek to run. It is an exception to not consume all input.

Similar to decodeExPortionWith, but runs in the IO monad.

Like decodeIOWith, but using Ptr and length instead of a ByteString.

Like decodeIOPortionWith, but using Ptr and length instead of a ByteString.

A poke implementation based on an instance of Storable.

A peek implementation based on an instance of Storable and Typeable.

A peek implementation based on an instance of Storable. Use this if the type is not Typeable.

Copy a section of memory, based on a ForeignPtr, to the output. Note that this operation is unsafe, the offset and length parameters are not checked.

Allocate a plain ForeignPtr (no finalizers), of the specified length and fill it with bytes from the input.

Copy a section of memory, based on a Ptr, to the output. Note that this operation is unsafe, because the offset and length parameters are not checked.

Copy a section of memory, based on a ByteArray#, to the output. Note that this operation is unsafe, because the offset and length parameters are not checked.

Allocate a ByteArray of the specified length and fill it with bytes from the input.

Make a PokeState from a buffer pointer.

The first argument is a pointer to the memory to write to. The second argument is an IO action which is invoked if the store-core package was built with the force-alignment flag. The action should yield a pointer to scratch memory as large as maybeAlignmentBufferSize.

Since 0.4.2

Make a PeekState from a buffer pointer.

The first argument is a pointer to the memory to write to. The second argument is an IO action which is invoked if the store-core package was built with the force-alignment flag. The action should yield a pointer to scratch memory as large as maybeAlignmentBufferSize.

Since 0.4.2

If store-core is built with the force-alignment flag, then this will be a Just value indicating the amount of memory that is expected in the alignment buffer used by PeekState and PokeState. Currently this will either be Just 32 or Nothing.