Refs #1: added detection of DCM images

atrcopy/__init__.py

@@ -20,7 +20,7 @@ from .kboot import KBootImage, add_xexboot_header
 from .segments import SegmentData, SegmentSaver, DefaultSegment, EmptySegment, ObjSegment, RawSectorsSegment, SegmentedFileSegment, user_bit_mask, match_bit_mask, comment_bit_mask, data_style, selected_bit_mask, diff_bit_mask, not_user_bit_mask, interleave_segments, SegmentList, get_style_mask, get_style_bits
 from .spartados import SpartaDosDiskImage
 from .cartridge import A8CartHeader, AtariCartImage
-from .parsers import SegmentParser, DefaultSegmentParser, guess_parser_for_mime, guess_parser_for_system, iter_parsers, iter_known_segment_parsers, mime_parse_order, parsers_for_filename
+from .parsers import SegmentParser, DefaultSegmentParser, guess_parser_for_mime, guess_parser_for_system, guess_container, iter_known_segment_parsers, mime_parse_order, parsers_for_filename
 from .magic import guess_detail_for_mime
 from .utils import to_numpy, text_to_int
 
@@ -60,6 +60,11 @@ def find_diskimage(filename):
                 print("Loading file %s" % filename)
             rawdata = SegmentData(fh.read())
             parser = None
+            try:
+                unpacked = guess_container(rawdata.data)
+            except errors.UnsupportedContainer as e:
+                print(f"{filename}: {e}")
+                return None
             for mime in mime_parse_order:
                 if options.verbose:
                     print("Trying MIME type %s" % mime)

atrcopy/container.py

@@ -0,0 +1,12 @@
+import numpy as np
+
+from . import errors
+from .segments import SegmentData
+
+
+class DiskImageContainer:
+    def __init__(self, data):
+        self.unpacked = self.unpack_raw_data(data)
+
+    def unpack_raw_data(self, data):
+        pass

atrcopy/dcm.py

@@ -0,0 +1,41 @@
+import numpy as np
+
+from . import errors
+from .container import DiskImageContainer
+from .segments import SegmentData
+
+
+class DCMContainer(DiskImageContainer):
+    valid_densities = {
+        0: (720, 128),
+        1: (720, 256),
+        2: (1040, 128),
+    }
+
+    def get_next(self):
+        try:
+            data = self.raw[self.index]
+        except IndexError:
+            raise errors.InvalidContainer
+        else:
+            self.index += 1
+        return data
+
+    def unpack_raw_data(self, data):
+        self.index = 0
+        self.count = len(data)
+        self.raw = data
+        archive_type = self.get_next()
+        if archive_type == 0xf9 or archive_type == 0xfa:
+            archive_flags = self.get_next()
+            if archive_flags & 0x1f != 1:
+                if archive_type == 0xf9:
+                    raise errors.InvalidContainer("DCM multi-file archive combined in the wrong order")
+                else:
+                    raise errors.InvalidContainer("Expected pass one of DCM archive first")
+            density_flag = (archive_flags >> 5) & 3
+            if density_flag not in self.valid_densities:
+                raise errors.InvalidContainer(f"Unsupported density flag {density_flag} in DCM")
+        else:
+            raise errors.InvalidContainer("Not a DCM file")
+        raise errors.UnsupportedContainer("DCM archives are not yet supported")

atrcopy/errors.py

@@ -65,3 +65,11 @@ class NotEnoughSpaceOnDisk(AtrError):
 
 class FileNotFound(AtrError):
     pass
+
+
+class UnsupportedContainer(AtrError):
+    pass
+
+
+class InvalidContainer(AtrError):
+    pass

atrcopy/parsers.py

@@ -10,6 +10,7 @@ from .dos33 import Dos33DiskImage, ProdosDiskImage, Dos33BinFile
 from .standard_delivery import StandardDeliveryImage
 from . import errors
 from .magic import guess_detail_for_mime
+from .dcm import DCMContainer
 
 import logging
 log = logging.getLogger(__name__)
@@ -157,6 +158,22 @@ class ProdosSegmentParser(SegmentParser):
     image_type = ProdosDiskImage
 
 
+known_containers = [
+    DCMContainer,
+]
+
+
+def guess_container(r):
+    for c in known_containers:
+        try:
+            found = c(r)
+        except errors.InvalidContainer:
+            continue
+        else:
+            return found
+    return None
+
+
 def guess_parser_for_mime(mime, r, verbose=False):
     parsers = mime_parsers[mime]
     found = None
@@ -182,6 +199,9 @@ def guess_parser_for_system(mime_base, r):
 
 
 def iter_parsers(r):
+    container = guess_container(r.data)
+    if container is not None:
+        r = container.unpacked
     for mime in mime_parse_order:
         p = guess_parser_for_mime(mime, r)
         if p is not None: