GLib.Bytes¶

Fields¶

None

Methods¶

class	`new` (data)
class	`new_take` (data)
	`compare` (bytes2)
	`equal` (bytes2)
	`get_data` ()
	`get_region` (element_size, offset, n_elements)
	`get_size` ()
	`hash` ()
	`new_from_bytes` (offset, length)
	`ref` ()
	`unref` ()
	`unref_to_array` ()
	`unref_to_data` ()

Details¶

class GLib.Bytes¶

A simple refcounted data type representing an immutable sequence of zero or more bytes from an unspecified origin.

The purpose of a GLib.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 GLib.Bytes without coordinating their activities, resting assured that the byte data will not change or move while they hold a reference.

A GLib.Bytes can come from many different origins that may have different procedures for freeing the memory region. Examples are memory from GLib.malloc(), from memory slices, from a GLib.MappedFile or memory from other allocators.

GLib.Bytes work well as keys in GLib.HashTable. Use GLib.Bytes.equal() and GLib.Bytes.hash() as parameters to g_hash_table_new() or g_hash_table_new_full(). GLib.Bytes can also be used as keys in a GLib.Tree by passing the GLib.Bytes.compare() function to g_tree_new().

The data pointed to by this bytes must not be modified. For a mutable array of bytes see GLib.ByteArray. Use GLib.Bytes.unref_to_array() to create a mutable array for a GLib.Bytes sequence. To create an immutable GLib.Bytes from a mutable GLib.ByteArray, use the GLib.ByteArray.free_to_bytes() function.

New in version 2.32.

classmethod new(data)[source]¶

Parameters:: data (bytes or None) – the data to be used for the bytes
Returns:: a new GLib.Bytes
Return type:: GLib.Bytes

Creates a new GLib.Bytes from data.

data is copied. If size is 0, data may be None.

New in version 2.32.

classmethod new_take(data)[source]¶

Parameters:: data (bytes or None) – the data to be used for the bytes
Returns:: a new GLib.Bytes
Return type:: GLib.Bytes

Creates a new GLib.Bytes from data.

After this call, data belongs to the GLib.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 GLib.free().

For creating GLib.Bytes with memory from other allocators, see g_bytes_new_with_free_func().

data may be None if size is 0.

New in version 2.32.

compare(bytes2)[source]¶

Parameters:: bytes2 (GLib.Bytes) – a pointer to a GLib.Bytes to compare with self
Returns:: a negative value if self is less than bytes2, a positive value if self is greater than bytes2, and zero if self is equal to bytes2
Return type:: int

Compares the two GLib.Bytes values.

This function can be used to sort GLib.Bytes instances in lexicographical order.

If self 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 self has a smaller value at that position it is considered less, otherwise greater than bytes2.

New in version 2.32.

equal(bytes2)[source]¶

Parameters:: bytes2 (GLib.Bytes) – a pointer to a GLib.Bytes to compare with self
Returns:: True if the two keys match.
Return type:: bool

Compares the two GLib.Bytes values being pointed to and returns True if they are equal.

This function can be passed to g_hash_table_new() as the key_equal_func parameter, when using non-None GLib.Bytes pointers as keys in a GLib.HashTable.

New in version 2.32.

get_data()[source]¶

Returns:: a pointer to the byte data, or None
Return type:: bytes or None

Get the byte data in the GLib.Bytes. This data should not be modified.

This function will always return the same pointer for a given GLib.Bytes.

None may be returned if size is 0. This is not guaranteed, as the GLib.Bytes may represent an empty string with data non-None and size as 0. None will not be returned if size is non-zero.

New in version 2.32.

get_region(element_size, offset, n_elements)[source]¶

Parameters:

element_size (int) – a non-zero element size
offset (int) – an offset to the start of the region within the self
n_elements (int) – the number of elements in the region

Returns:

the requested region, or None in case of an error

Return type:

object or None

Gets a pointer to a region in self.

The region starts at offset many bytes from the start of the data and contains n_elements many elements of element_size size.

n_elements may be zero, but element_size must always be non-zero. Ideally, element_size is a static constant (eg: sizeof a struct).

This function does careful bounds checking (including checking for arithmetic overflows) and returns a non-None pointer if the specified region lies entirely within the self. If the region is in some way out of range, or if an overflow has occurred, then None 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 self, plus offset. This will be non-None except for the case where self 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 self, None effectively always means “error”.

New in version 2.70.

get_size()[source]¶

Returns:: the size
Return type:: int

Get the size of the byte data in the GLib.Bytes.

This function will always return the same value for a given GLib.Bytes.

New in version 2.32.

hash()[source]¶

Returns:: a hash value corresponding to the key.
Return type:: int

Creates an integer hash code for the byte data in the GLib.Bytes.

This function can be passed to g_hash_table_new() as the key_hash_func parameter, when using non-None GLib.Bytes pointers as keys in a GLib.HashTable.

New in version 2.32.

new_from_bytes(offset, length)[source]¶

Parameters:

offset (int) – offset which subsection starts at
length (int) – length of subsection

Returns:

a new GLib.Bytes

Return type:

GLib.Bytes

Creates a GLib.Bytes which is a subsection of another GLib.Bytes. The offset + length may not be longer than the size of self.

A reference to self will be held by the newly created GLib.Bytes until the byte data is no longer needed.

Since 2.56, if offset is 0 and length matches the size of self, then self will be returned with the reference count incremented by 1. If self is a slice of another GLib.Bytes, then the resulting GLib.Bytes will reference the same GLib.Bytes instead of self. This allows consumers to simplify the usage of GLib.Bytes when asynchronously writing to streams.

New in version 2.32.

ref()[source]¶

Returns:: the GLib.Bytes
Return type:: GLib.Bytes

Increase the reference count on self.

New in version 2.32.

unref()[source]¶: Releases a reference on self. This may result in the bytes being freed. If self is None, it will return immediately.

New in version 2.32.

unref_to_array()[source]¶

Returns:: a new mutable GLib.ByteArray containing the same byte data
Return type:: bytes

Unreferences the bytes, and returns a new mutable GLib.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 GLib.Bytes.new(), GLib.Bytes.new_take() or GLib.ByteArray.free_to_bytes(). In all other cases the data is copied.

Do not use it if self contains more than %G_MAXUINT bytes. GLib.ByteArray stores the length of its data in int, which may be shorter than #gsize, that self is using.

New in version 2.32.

unref_to_data()[source]¶

Returns:: a pointer to the same byte data, which should be freed with GLib.free()
Return type:: bytes

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 GLib.Bytes.new(), GLib.Bytes.new_take() or GLib.ByteArray.free_to_bytes(). In all other cases the data is copied.

New in version 2.32.