Datagram¶

from acron.core import Datagram

class Datagram¶

Bases:

Bases: TypedObject

An ordered list of data elements, formatted in memory for transmission over a socket or writing to a data file.

Data elements should be added one at a time, in order, to the Datagram. The nature and contents of the data elements are totally up to the user. When a Datagram has been transmitted and received, its data elements may be extracted using a DatagramIterator; it is up to the caller to know the correct type of each data element in order.

A Datagram is itself headerless; it is simply a collection of data elements.

Inheritance diagram

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__bytes__()¶

__eq__()¶

__init__()¶

Constructs a datagram from an existing block of data.

__lt__()¶

__ne__()¶

__reduce__()¶

add_be_float32()¶: Adds a 32-bit single-precision big-endian floating-point number to the datagram.

add_be_float64()¶: Adds a 64-bit big-endian floating-point number to the datagram.

add_be_int16()¶

These functions pack numbers big-endian, in case that’s desired.

Adds a signed 16-bit big-endian integer to the datagram.

add_be_int32()¶: Adds a signed 32-bit big-endian integer to the datagram.

add_be_int64()¶: Adds a signed 64-bit big-endian integer to the datagram.

add_be_uint16()¶: Adds an unsigned 16-bit big-endian integer to the datagram.

add_be_uint32()¶: Adds an unsigned 32-bit big-endian integer to the datagram.

add_be_uint64()¶: Adds an unsigned 64-bit big-endian integer to the datagram.

add_blob()¶: Adds a variable-length binary blob to the datagram. This actually adds a count followed by n bytes.

add_blob32()¶: Adds a variable-length binary blob to the datagram, using a 32-bit length field to allow very long blobs.

add_bool()¶: Adds a boolean value to the datagram.

add_fixed_string()¶: Adds a fixed-length string to the datagram. If the string given is less than the requested size, this will pad the string out with zeroes; if it is greater than the requested size, this will silently truncate the string.

add_float32()¶: Adds a 32-bit single-precision floating-point number to the datagram. Since this kind of float is not necessarily portable across different architectures, special care is required.

add_float64()¶: Adds a 64-bit floating-point number to the datagram.

add_int16()¶

The default numeric packing is little-endian.

Adds a signed 16-bit integer to the datagram.

add_int32()¶: Adds a signed 32-bit integer to the datagram.

add_int64()¶: Adds a signed 64-bit integer to the datagram.

add_int8()¶: Adds a signed 8-bit integer to the datagram.

add_stdfloat()¶: Adds either a 32-bit or a 64-bit floating-point number, according to set_stdfloat_double().

add_string()¶: Adds a variable-length string to the datagram. This actually adds a count followed by n bytes.

add_string32()¶: Adds a variable-length string to the datagram, using a 32-bit length field to allow very long strings.

add_uint16()¶: Adds an unsigned 16-bit integer to the datagram.

add_uint32()¶: Adds an unsigned 32-bit integer to the datagram.

add_uint64()¶: Adds an unsigned 64-bit integer to the datagram.

add_uint8()¶: Adds an unsigned 8-bit integer to the datagram.

add_wstring()¶: Adds a variable-length wstring to the datagram.

add_z_string()¶: Adds a variable-length string to the datagram, as a NULL-terminated string.

append_data()¶

Appends some more raw data to the end of the datagram.

assign()¶

clear()¶: Resets the datagram to empty, in preparation for building up a new datagram.

copy_array()¶: Replaces the data in the Datagram with a copy of the data in the indicated CPTA_uchar. Unlike set_array(), a complete copy is made of the data; subsequent changes to the Datagram will not change the source CPTA_uchar.

dump_hex()¶: Writes a representation of the entire datagram contents, as a sequence of hex (and ASCII) values.

get_array()¶: Returns a const pointer to the actual data in the Datagram.

static get_class_type()¶

get_length()¶: Returns the number of bytes in the datagram.

get_message()¶: Returns the datagram’s data as a string.

get_stdfloat_double()¶: Returns the stdfloat_double flag. See set_stdfloat_double().

modify_array()¶: Returns a modifiable pointer to the actual data in the Datagram.

output()¶: Write a string representation of this instance to <out>.

pad_bytes()¶: Adds the indicated number of zero bytes to the datagram.

set_array()¶: Replaces the data in the Datagram with the data in the indicated PTA_uchar. This is assignment by reference: subsequent changes to the Datagram will also change the source PTA_uchar.

set_stdfloat_double()¶: Changes the stdfloat_double flag, which defines the operation performed by add_stdfloat() and DatagramIterator.get_stdfloat(). When this is true, add_stdfloat() adds a 64-bit floating-point number; when it is false, it adds a 32-bit floating-point number. The default is based on the STDFLOAT_DOUBLE compilation flag.

write()¶: Write a string representation of this instance to <out>.