Add simple Packet Buffer test examples

examples/ble_packet_buffer_client.py

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+# SPDX-FileCopyrightText: 2022 Scott Shawcroft for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+"""
+Used with ble_packet_buffer_test.py. Transmits "echo" to
+PacketBufferService and receives it back.
+"""
+
+import time
+
+from ble_packet_buffer_service import PacketBufferService
+
+from adafruit_ble import BLERadio
+from adafruit_ble.advertising.standard import ProvideServicesAdvertisement
+
+ble = BLERadio()
+buf = bytearray(512)
+while True:
+    while ble.connected and any(
+        PacketBufferService in connection for connection in ble.connections
+    ):
+        for connection in ble.connections:
+            if PacketBufferService not in connection:
+                continue
+            print("echo")
+            pb = connection[PacketBufferService]
+            pb.write(b"echo")
+            # Returns 0 if nothing was read.
+            packet_len = pb.readinto(buf)
+            if packet_len > 0:
+                print(buf[:packet_len])
+            print()
+        time.sleep(1)
+
+    print("disconnected, scanning")
+    for advertisement in ble.start_scan(ProvideServicesAdvertisement, timeout=1):
+        if PacketBufferService not in advertisement.services:
+            continue
+        ble.connect(advertisement)
+        print("connected")
+        break
+    ble.stop_scan()

examples/ble_packet_buffer_service.py

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+# SPDX-FileCopyrightText: 2022 Scott Shawcroft for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+"""
+Used with ble_packet_buffer_*.py. Establishes a simple server to test
+PacketBuffer with.
+"""
+
+import _bleio
+
+from adafruit_ble.services import Service
+from adafruit_ble.characteristics import (
+    Attribute,
+    Characteristic,
+    ComplexCharacteristic,
+)
+from adafruit_ble.uuid import VendorUUID
+
+
+class PacketBufferUUID(VendorUUID):
+    """UUIDs with the PacketBuffer base UUID."""
+
+    # pylint: disable=too-few-public-methods
+
+    def __init__(self, uuid16):
+        uuid128 = bytearray("reffuBtekcaP".encode("utf-8") + b"\x00\x00\xaf\xad")
+        uuid128[-3] = uuid16 >> 8
+        uuid128[-4] = uuid16 & 0xFF
+        super().__init__(uuid128)
+
+
+class PacketBufferCharacteristic(ComplexCharacteristic):
+    def __init__(
+        self,
+        *,
+        uuid=None,
+        buffer_size=4,
+        properties=Characteristic.WRITE_NO_RESPONSE
+        | Characteristic.NOTIFY
+        | Characteristic.READ,
+        read_perm=Attribute.OPEN,
+        write_perm=Attribute.OPEN
+    ):
+        self.buffer_size = buffer_size
+        super().__init__(
+            uuid=uuid,
+            properties=properties,
+            read_perm=read_perm,
+            write_perm=write_perm,
+            max_length=512,
+            fixed_length=False,
+        )
+
+    def bind(self, service):
+        """Binds the characteristic to the given Service."""
+        bound_characteristic = super().bind(service)
+        return _bleio.PacketBuffer(
+            bound_characteristic, buffer_size=self.buffer_size, max_packet_size=512
+        )
+
+
+class PacketBufferService(Service):
+    """Test service that has one packet buffer"""
+
+    uuid = PacketBufferUUID(0x0001)
+
+    packets = PacketBufferCharacteristic(uuid=PacketBufferUUID(0x0101))
+
+    def readinto(self, buf):
+        return self.packets.readinto(buf)
+
+    def write(self, buf, *, header=None):
+        return self.packets.write(buf, header=header)

examples/ble_packet_buffer_test.py

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+# SPDX-FileCopyrightText: 2020 ladyada for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+"""
+Can be used with ble_packet_buffer_client.py. Receives packets from the
+PacketBufferService and transmits them back.
+"""
+
+from packet_buffer_service import PacketBufferService
+
+from adafruit_ble import BLERadio
+from adafruit_ble.advertising.standard import ProvideServicesAdvertisement
+
+
+ble = BLERadio()
+pbs = PacketBufferService()
+advertisement = ProvideServicesAdvertisement(pbs)
+
+buf = bytearray(512)
+
+while True:
+    ble.start_advertising(advertisement)
+    while not ble.connected:
+        pass
+    while ble.connected:
+        # Returns b'' if nothing was read.
+        packet_len = pbs.readinto(buf)
+        if packet_len > 0:
+            packet = buf[:packet_len]
+            print(packet)
+            pbs.write(packet)