add circuitpython code

1 files changed, 76 insertions, 0 deletions

diff --git a/circuitpython/lib/nrfutil/nordicsemi/bluetooth/hci/codec.py b/circuitpython/lib/nrfutil/nordicsemi/bluetooth/hci/codec.py
new file mode 100644
index 0000000..bebd790
--- /dev/null
+++ b/circuitpython/lib/nrfutil/nordicsemi/bluetooth/hci/codec.py
@@ -0,0 +1,76 @@
+# Copyright (c) 2015, Nordic Semiconductor
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# * Redistributions of source code must retain the above copyright notice, this
+#   list of conditions and the following disclaimer.
+#
+# * Redistributions in binary form must reproduce the above copyright notice,
+#   this list of conditions and the following disclaimer in the documentation
+#   and/or other materials provided with the distribution.
+#
+# * Neither the name of Nordic Semiconductor ASA nor the names of its
+#   contributors may be used to endorse or promote products derived from
+#   this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+UART_HEADER_OCTET_COUNT = 4
+
+
+class ThreeWireUartPacket(object):
+    """
+    This class encapsulate a three wire uart packet according to Bluetooth specification
+    version 4.0 [Vol 4] part D.
+    """
+    def __init__(self):
+        self.ack = None  # Acknowledgement number
+        self.seq = None  # Sequence number
+        self.di = None  # Data integrity present
+        self.rp = None  # Reliable packet
+        self.type = None  # Packet type
+        self.length = None  # Payload Length
+        self.checksum = None  # Header checksum
+        self.payload = None  # Payload
+
+    @staticmethod
+    def decode(packet):
+        """
+        Decodes a packet from a str encoded array
+
+        :param packet_bytes: A str encoded array
+        :return: TheeWireUartPacket
+        """
+
+        decoded_packet = ThreeWireUartPacket()
+
+        packet_bytes = bytearray(packet)
+
+        decoded_packet.ack = (packet_bytes[0] & int('38', 16)) >> 3
+        decoded_packet.seq = (packet_bytes[0] & int('07', 16))
+        decoded_packet.di = (packet_bytes[0] & int('40', 16)) >> 6
+        decoded_packet.rp = (packet_bytes[0] & int('80', 16)) >> 7
+        decoded_packet.type = (packet_bytes[1] & int('0F', 16))
+        decoded_packet.length = ((packet_bytes[1] & int('F0', 16)) >> 4) + (packet_bytes[2] * 16)
+
+        checksum = packet_bytes[0]
+        checksum = checksum + packet_bytes[1]
+        checksum = checksum + packet_bytes[2]
+        checksum &= int('FF', 16)
+        decoded_packet.checksum = (~checksum + 1) & int('FF', 16)
+
+        if decoded_packet.length > 0:
+            decoded_packet.payload = packet_bytes[UART_HEADER_OCTET_COUNT:-1]
+
+        return decoded_packet