about summary refs log tree commit diff
path: root/.venv/lib/python3.12/site-packages/dns/wire.py
diff options
context:
space:
mode:
Diffstat (limited to '.venv/lib/python3.12/site-packages/dns/wire.py')
-rw-r--r--.venv/lib/python3.12/site-packages/dns/wire.py89
1 files changed, 89 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/dns/wire.py b/.venv/lib/python3.12/site-packages/dns/wire.py
new file mode 100644
index 00000000..9f9b1573
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/dns/wire.py
@@ -0,0 +1,89 @@
+# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
+
+import contextlib
+import struct
+from typing import Iterator, Optional, Tuple
+
+import dns.exception
+import dns.name
+
+
+class Parser:
+    def __init__(self, wire: bytes, current: int = 0):
+        self.wire = wire
+        self.current = 0
+        self.end = len(self.wire)
+        if current:
+            self.seek(current)
+        self.furthest = current
+
+    def remaining(self) -> int:
+        return self.end - self.current
+
+    def get_bytes(self, size: int) -> bytes:
+        assert size >= 0
+        if size > self.remaining():
+            raise dns.exception.FormError
+        output = self.wire[self.current : self.current + size]
+        self.current += size
+        self.furthest = max(self.furthest, self.current)
+        return output
+
+    def get_counted_bytes(self, length_size: int = 1) -> bytes:
+        length = int.from_bytes(self.get_bytes(length_size), "big")
+        return self.get_bytes(length)
+
+    def get_remaining(self) -> bytes:
+        return self.get_bytes(self.remaining())
+
+    def get_uint8(self) -> int:
+        return struct.unpack("!B", self.get_bytes(1))[0]
+
+    def get_uint16(self) -> int:
+        return struct.unpack("!H", self.get_bytes(2))[0]
+
+    def get_uint32(self) -> int:
+        return struct.unpack("!I", self.get_bytes(4))[0]
+
+    def get_uint48(self) -> int:
+        return int.from_bytes(self.get_bytes(6), "big")
+
+    def get_struct(self, format: str) -> Tuple:
+        return struct.unpack(format, self.get_bytes(struct.calcsize(format)))
+
+    def get_name(self, origin: Optional["dns.name.Name"] = None) -> "dns.name.Name":
+        name = dns.name.from_wire_parser(self)
+        if origin:
+            name = name.relativize(origin)
+        return name
+
+    def seek(self, where: int) -> None:
+        # Note that seeking to the end is OK!  (If you try to read
+        # after such a seek, you'll get an exception as expected.)
+        if where < 0 or where > self.end:
+            raise dns.exception.FormError
+        self.current = where
+
+    @contextlib.contextmanager
+    def restrict_to(self, size: int) -> Iterator:
+        assert size >= 0
+        if size > self.remaining():
+            raise dns.exception.FormError
+        saved_end = self.end
+        try:
+            self.end = self.current + size
+            yield
+            # We make this check here and not in the finally as we
+            # don't want to raise if we're already raising for some
+            # other reason.
+            if self.current != self.end:
+                raise dns.exception.FormError
+        finally:
+            self.end = saved_end
+
+    @contextlib.contextmanager
+    def restore_furthest(self) -> Iterator:
+        try:
+            yield None
+        finally:
+            self.current = self.furthest