From f745ce94f71c16927b7ddb91986d6c026c21e7ba Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Diego=20Elio=20Petten=C3=B2?= <flameeyes@flameeyes.com>
Date: Sun, 4 Oct 2020 15:08:43 +0100
Subject: Initial import of freestyle-hid.

This library is a factor-out of
https://github.com/glucometers-tech/glucometerutils to only include the
FreeStyle implementation, to make it easier to use outside of
glucometerutils, and in particular to make it easier to build better
reverse engineering tooling around it.

Note that since the code was a mix of MIT and Apache-2.0 license, the
overall license of the library is written down as Apache-2.0, as that would
be a super-set of the requirements from MIT.
---
 freestyle_hid/_hidwrapper.py | 66 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 freestyle_hid/_hidwrapper.py

(limited to 'freestyle_hid/_hidwrapper.py')

diff --git a/freestyle_hid/_hidwrapper.py b/freestyle_hid/_hidwrapper.py
new file mode 100644
index 0000000..a82bd4c
--- /dev/null
+++ b/freestyle_hid/_hidwrapper.py
@@ -0,0 +1,66 @@
+# SPDX-FileCopyrightText: © 2020 The freestyle-hid Authors
+# SPDX-License-Identifier: Apache-2.0
+"""HID wrappers to access files with either hidraw or cython-hidapi."""
+
+import abc
+import pathlib
+from typing import BinaryIO, Optional, Union
+
+try:
+    import hid
+except ImportError:
+    hid = None
+
+from ._exceptions import HIDError
+
+
+class HidWrapper(abc.ABC):
+
+    _handle: Union[BinaryIO, "hid.device"]
+
+    def write(self, report: bytes) -> None:
+        if len(report) > 65:
+            raise HIDError(f"Invalid report length {len(report)}.")
+
+        written = self._handle.write(report)
+        if written < 0:
+            raise HIDError(f"Invalid write ({written}).")
+
+    @abc.abstractmethod
+    def read(self, size: int = 64) -> bytes:
+        pass
+
+    @staticmethod
+    def open(
+        device_path: Optional[pathlib.Path], vendor_id: int, product_id: Optional[int]
+    ) -> "HidWrapper":
+        if device_path:
+            return HidRaw(device_path)
+        else:
+            assert product_id is not None
+            return HidApi(vendor_id, product_id)
+
+
+class HidRaw(HidWrapper):
+    def __init__(self, device_path: pathlib.Path) -> None:
+        if not device_path.exists():
+            raise ValueError(f"Path {device_path} does not exists.")
+
+        self._handle = device_path.open("w+b")
+
+    def read(self, size: int = 64) -> bytes:
+        return self._handle.read(size)
+
+
+class HidApi(HidWrapper):
+    _handle: "hid.device"
+
+    def __init__(self, vendor_id: int, product_id: int) -> None:
+        if hid is None:
+            raise ValueError("cython-hidapi not found.")
+
+        self._handle = hid.device()
+        self._handle.open(vendor_id, product_id)
+
+    def read(self, size: int = 64) -> bytes:
+        return bytes(self._handle.read(size, timeout_ms=0))
-- 
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