add circuitpython code

1 files changed, 99 insertions, 0 deletions

diff --git a/circuitpython/tools/upip_utarfile.py b/circuitpython/tools/upip_utarfile.py
new file mode 100644
index 0000000..3e527fa
--- /dev/null
+++ b/circuitpython/tools/upip_utarfile.py
@@ -0,0 +1,99 @@
+# SPDX-FileCopyrightText: 2014 MicroPython & CircuitPython contributors (https://github.com/adafruit/circuitpython/graphs/contributors)
+#
+# SPDX-License-Identifier: MIT
+
+import uctypes
+
+# http://www.gnu.org/software/tar/manual/html_node/Standard.html
+TAR_HEADER = {
+    "name": (uctypes.ARRAY | 0, uctypes.UINT8 | 100),
+    "size": (uctypes.ARRAY | 124, uctypes.UINT8 | 11),
+}
+
+DIRTYPE = "dir"
+REGTYPE = "file"
+
+
+def roundup(val, align):
+    return (val + align - 1) & ~(align - 1)
+
+
+class FileSection:
+    def __init__(self, f, content_len, aligned_len):
+        self.f = f
+        self.content_len = content_len
+        self.align = aligned_len - content_len
+
+    def read(self, sz=65536):
+        if self.content_len == 0:
+            return b""
+        if sz > self.content_len:
+            sz = self.content_len
+        data = self.f.read(sz)
+        sz = len(data)
+        self.content_len -= sz
+        return data
+
+    def readinto(self, buf):
+        if self.content_len == 0:
+            return 0
+        if len(buf) > self.content_len:
+            buf = memoryview(buf)[: self.content_len]
+        sz = self.f.readinto(buf)
+        self.content_len -= sz
+        return sz
+
+    def skip(self):
+        sz = self.content_len + self.align
+        if sz:
+            buf = bytearray(16)
+            while sz:
+                s = min(sz, 16)
+                self.f.readinto(buf, s)
+                sz -= s
+
+
+class TarInfo:
+    def __str__(self):
+        return "TarInfo(%r, %s, %d)" % (self.name, self.type, self.size)
+
+
+class TarFile:
+    def __init__(self, name=None, fileobj=None):
+        if fileobj:
+            self.f = fileobj
+        else:
+            self.f = open(name, "rb")
+        self.subf = None
+
+    def next(self):
+        if self.subf:
+            self.subf.skip()
+        buf = self.f.read(512)
+        if not buf:
+            return None
+
+        h = uctypes.struct(uctypes.addressof(buf), TAR_HEADER, uctypes.LITTLE_ENDIAN)
+
+        # Empty block means end of archive
+        if h.name[0] == 0:
+            return None
+
+        d = TarInfo()
+        d.name = str(h.name, "utf-8").rstrip("\0")
+        d.size = int(bytes(h.size), 8)
+        d.type = [REGTYPE, DIRTYPE][d.name[-1] == "/"]
+        self.subf = d.subf = FileSection(self.f, d.size, roundup(d.size, 512))
+        return d
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        v = self.next()
+        if v is None:
+            raise StopIteration
+        return v
+
+    def extractfile(self, tarinfo):
+        return tarinfo.subf