GLib.Bytes

Fields

None

Methods

class new (data)
class new_take (data)
  compare (bytes2)
  equal (bytes2)
  get_data ()
  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 bytes and may no longer be modified by the caller. GLib.free() will be called on data when the bytes is no longer in use. Because of this data must have been created by a call to GLib.malloc(), GLib.malloc0() or GLib.realloc() or by one of the many functions that wrap these calls (such as g_new(), GLib.strdup(), etc).

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_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.

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.