| Copyright | Will Thompson and Iñaki García Etxebarria |
|---|---|
| License | LGPL-2.1 |
| Maintainer | Iñaki García Etxebarria |
| Safe Haskell | Safe-Inferred |
| Language | Haskell2010 |
GI.GLib.Structs.Bytes
Description
A simple refcounted data type representing an immutable sequence of zero or more bytes from an unspecified origin.
The purpose of a Bytes is to keep the memory region that it holds
alive for as long as anyone holds a reference to the bytes. When
the last reference count is dropped, the memory is released. Multiple
unrelated callers can use byte data in the Bytes without coordinating
their activities, resting assured that the byte data will not change or
move while they hold a reference.
A Bytes can come from many different origins that may have
different procedures for freeing the memory region. Examples are
memory from malloc, from memory slices, from a MappedFile or
memory from other allocators.
Bytes work well as keys in HashTable. Use bytesEqual and
bytesHash as parameters to g_hash_table_new() or g_hash_table_new_full().
Bytes can also be used as keys in a Tree by passing the bytesCompare
function to g_tree_new().
The data pointed to by this bytes must not be modified. For a mutable
array of bytes see ByteArray. Use bytesUnrefToArray to create a
mutable array for a Bytes sequence. To create an immutable Bytes from
a mutable ByteArray, use the byteArrayFreeToBytes function.
Since: 2.32
Synopsis
- newtype Bytes = Bytes (ManagedPtr Bytes)
- bytesCompare :: (HasCallStack, MonadIO m) => Bytes -> Bytes -> m Int32
- bytesEqual :: (HasCallStack, MonadIO m) => Bytes -> Bytes -> m Bool
- bytesGetData :: (HasCallStack, MonadIO m) => Bytes -> m (Maybe ByteString)
- bytesGetRegion :: (HasCallStack, MonadIO m) => Bytes -> CSize -> CSize -> CSize -> m (Ptr ())
- bytesGetSize :: (HasCallStack, MonadIO m) => Bytes -> m CSize
- bytesHash :: (HasCallStack, MonadIO m) => Bytes -> m Word32
- bytesNew :: (HasCallStack, MonadIO m) => Maybe ByteString -> m Bytes
- bytesNewFromBytes :: (HasCallStack, MonadIO m) => Bytes -> CSize -> CSize -> m Bytes
- bytesNewTake :: (HasCallStack, MonadIO m) => Maybe ByteString -> m Bytes
- bytesRef :: (HasCallStack, MonadIO m) => Bytes -> m Bytes
- bytesUnref :: (HasCallStack, MonadIO m) => Maybe Bytes -> m ()
- bytesUnrefToArray :: (HasCallStack, MonadIO m) => Bytes -> m ByteString
- bytesUnrefToData :: (HasCallStack, MonadIO m) => Bytes -> m ByteString
Exported types
Memory-managed wrapper type.
Instances
| Eq Bytes Source # | |
| GBoxed Bytes Source # | |
Defined in GI.GLib.Structs.Bytes | |
| ManagedPtrNewtype Bytes Source # | |
Defined in GI.GLib.Structs.Bytes Methods toManagedPtr :: Bytes -> ManagedPtr Bytes | |
| TypedObject Bytes Source # | |
Defined in GI.GLib.Structs.Bytes | |
| HasParentTypes Bytes Source # | |
Defined in GI.GLib.Structs.Bytes | |
| IsGValue (Maybe Bytes) Source # | Convert |
Defined in GI.GLib.Structs.Bytes Methods gvalueGType_ :: IO GType gvalueSet_ :: Ptr GValue -> Maybe Bytes -> IO () gvalueGet_ :: Ptr GValue -> IO (Maybe Bytes) | |
| type ParentTypes Bytes Source # | |
Defined in GI.GLib.Structs.Bytes | |
Methods
Click to display all available methods, including inherited ones
Methods
compare, equal, hash, newFromBytes, ref, unref, unrefToArray, unrefToData.
Getters
Setters
None.
compare
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Bytes |
|
| -> Bytes |
|
| -> m Int32 | Returns: a negative value if |
Compares the two Bytes values.
This function can be used to sort GBytes instances in lexicographical order.
If bytes1 and bytes2 have different length but the shorter one is a
prefix of the longer one then the shorter one is considered to be less than
the longer one. Otherwise the first byte where both differ is used for
comparison. If bytes1 has a smaller value at that position it is
considered less, otherwise greater than bytes2.
Since: 2.32
equal
getData
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Bytes |
|
| -> m (Maybe ByteString) | Returns:
a pointer to the byte data, or |
Get the byte data in the Bytes. This data should not be modified.
This function will always return the same pointer for a given Bytes.
Nothing may be returned if size is 0. This is not guaranteed, as the Bytes
may represent an empty string with data non-Nothing and size as 0. Nothing will
not be returned if size is non-zero.
Since: 2.32
getRegion
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Bytes |
|
| -> CSize |
|
| -> CSize |
|
| -> CSize |
|
| -> m (Ptr ()) | Returns: the requested region, or |
Gets a pointer to a region in bytes.
The region starts at offset many bytes from the start of the data
and contains nElements many elements of elementSize size.
nElements may be zero, but elementSize must always be non-zero.
Ideally, elementSize is a static constant (eg: sizeof a struct).
This function does careful bounds checking (including checking for
arithmetic overflows) and returns a non-Nothing pointer if the
specified region lies entirely within the bytes. If the region is
in some way out of range, or if an overflow has occurred, then Nothing
is returned.
Note: it is possible to have a valid zero-size region. In this case,
the returned pointer will be equal to the base pointer of the data of
bytes, plus offset. This will be non-Nothing except for the case
where bytes itself was a zero-sized region. Since it is unlikely
that you will be using this function to check for a zero-sized region
in a zero-sized bytes, Nothing effectively always means "error".
Since: 2.70
getSize
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Bytes |
|
| -> m CSize | Returns: the size |
hash
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Bytes |
|
| -> m Word32 | Returns: a hash value corresponding to the key. |
new
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Maybe ByteString |
|
| -> m Bytes | Returns: a new |
newFromBytes
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Bytes |
|
| -> CSize |
|
| -> CSize |
|
| -> m Bytes | Returns: a new |
Creates a Bytes which is a subsection of another Bytes. The offset +
length may not be longer than the size of bytes.
A reference to bytes will be held by the newly created Bytes until
the byte data is no longer needed.
Since 2.56, if offset is 0 and length matches the size of bytes, then
bytes will be returned with the reference count incremented by 1. If bytes
is a slice of another Bytes, then the resulting Bytes will reference
the same Bytes instead of bytes. This allows consumers to simplify the
usage of Bytes when asynchronously writing to streams.
Since: 2.32
newTake
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Maybe ByteString |
|
| -> m Bytes | Returns: a new |
Creates a new Bytes from data.
After this call, data belongs to the Bytes and may no longer be
modified by the caller. The memory of data has to be dynamically
allocated and will eventually be freed with free.
For creating Bytes with memory from other allocators, see
g_bytes_new_with_free_func().
data may be Nothing if size is 0.
Since: 2.32
ref
Increase the reference count on bytes.
Since: 2.32
unref
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Maybe Bytes |
|
| -> m () |
Releases a reference on bytes. This may result in the bytes being
freed. If bytes is Nothing, it will return immediately.
Since: 2.32
unrefToArray
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Bytes |
|
| -> m ByteString | Returns: a new mutable |
Unreferences the bytes, and returns a new mutable ByteArray containing
the same byte data.
As an optimization, the byte data is transferred to the array without copying
if this was the last reference to bytes and bytes was created with
bytesNew, bytesNewTake or byteArrayFreeToBytes. In all
other cases the data is copied.
Do not use it if bytes contains more than G_MAXUINT
bytes. ByteArray stores the length of its data in guint, which
may be shorter than gsize, that bytes is using.
Since: 2.32
unrefToData
Arguments
| :: (HasCallStack, MonadIO m) | |
| => Bytes |
|
| -> m ByteString | Returns: a pointer to the same byte data, which should be
freed with |
Unreferences the bytes, and returns a pointer the same byte data contents.
As an optimization, the byte data is returned without copying if this was
the last reference to bytes and bytes was created with bytesNew,
bytesNewTake or byteArrayFreeToBytes. In all other cases the
data is copied.
Since: 2.32