wip: first table header section

.vscode/settings.json

@@ -4,5 +4,7 @@
         "tests"
     ],
     "python.testing.unittestEnabled": false,
-    "python.testing.pytestEnabled": true
+    "python.testing.pytestEnabled": true,
+    "python.linting.flake8Enabled": true,
+    "python.linting.enabled": true
 }

pygpt_disk/disk.py

@@ -2,16 +2,18 @@
 
 
 class Disk:
+    sector_size = 512
+
     def __init__(self, size: int, name: str):
         self.size = size
         self.name = name
-        self.disk = io.BytesIO()
+        self.buffer = io.BytesIO()  # this is bad, it makes Disk.disk :(
 
     def create(self) -> None:
-        self.disk.seek(self.size - 1)
-        self.disk.write(b"\0")
+        self.buffer.seek(self.size - 1)
+        self.buffer.write(b"\0")
 
     def write(self) -> None:
         """Write a disk buffer to file"""
         with open(self.name, "wb") as f:
-            f.write(self.disk.getvalue())
+            f.write(self.buffer.getvalue())

pygpt_disk/table.py

@@ -0,0 +1,29 @@
+"""
+LBA 0 is the protective MBR
+
+LBA 1 is where the header starts
+
+Byte 0 - 7 (Signature) "EFI PART" or 45h 46h 49h 20h 50h 41h 52h
+Byte 8 - 11 (Revision) "1.0" or 00h 00h 01h 00h
+Byte 12 - 15 (Header size LE) 5Ch 00h 00h 00h (92 bytes)
+Byte 16 - 19 CRC32 of header from 0 to 15
+Byte 20 - 23 reserved (must be zero)
+Byte 24 - 31 Current LBA location
+Byte 32 - 39 Backup LBA location
+
+LBA 2 - 33 partitions
+"""
+from pygpt_disk.disk import Disk
+
+
+class Table:
+    _header_sig = b"\x45\x46\x49\x20\x50\x41\x52\x54"
+
+    def __init__(self, disk: Disk):
+        self.disk = disk
+
+    def create(self):
+        """Create blank GPT Table Header"""
+        # move to LBA 1
+        self.disk.buffer.seek(self.disk.sector_size - 1)
+        self.disk.buffer.write(Table._header_sig)

pyproject.toml

@@ -11,6 +11,7 @@ python = "^3.8"
 black = "^21.10b0"
 pytest = "^6.2.5"
 mypy = "^0.910"
+flake8 = "^4.0.1"
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]

tests/test_images.py

@@ -9,12 +9,13 @@ def test_init():
     d = disk.Disk(DISK_SIZE, DISK_NAME)
     assert d.size == DISK_SIZE
     assert d.name == DISK_NAME
+    assert d.sector_size == 512
 
 
 def test_create():
     d = disk.Disk(DISK_SIZE, DISK_NAME)
     d.create()
-    assert len(d.disk.getvalue()) == DISK_SIZE
+    assert len(d.buffer.getvalue()) == DISK_SIZE
 
 
 def test_write(tmp_path):

tests/test_table.py

@@ -0,0 +1,15 @@
+from pygpt_disk import table, disk
+import pytest
+
+
+@pytest.fixture
+def fresh_disk(tmp_path):
+    image_path = tmp_path / "table-test.img"
+    return disk.Disk(8 * 1024 * 1024, image_path)
+
+
+def test_init(fresh_disk: disk.Disk):
+    t = table.Table(fresh_disk)
+    t.create()
+    t.disk.buffer.seek(512 - 1)
+    assert t.disk.buffer.read(8) == b"EFI PART"