Initial check-in, not yet working and has old, unported BAM code

2018-02-22 14:50:10 +01:00
commit 0532634d13
9 changed files with 1013 additions and 0 deletions
@@ -0,0 +1,110 @@
+"""Read-write utility functions."""
+
+import struct
+import typing
+
+
+class LittleEndianTypes:
+    UCHAR = struct.Struct(b'<b')
+    USHORT = struct.Struct(b'<H')
+    USHORT2 = struct.Struct(b'<HH')  # two shorts in a row
+    SSHORT = struct.Struct(b'<h')
+    UINT = struct.Struct(b'<I')
+    SINT = struct.Struct(b'<i')
+    FLOAT = struct.Struct(b'<f')
+    ULONG = struct.Struct(b'<Q')
+
+    @classmethod
+    def _read(cls, fileobj: typing.BinaryIO, typestruct: struct.Struct):
+        data = fileobj.read(typestruct.size)
+        return typestruct.unpack(data)[0]
+
+    @classmethod
+    def read_char(cls, fileobj: typing.BinaryIO):
+        return cls._read(fileobj, cls.UCHAR)
+
+    @classmethod
+    def read_ushort(cls, fileobj: typing.BinaryIO):
+        return cls._read(fileobj, cls.USHORT)
+
+    @classmethod
+    def read_short(cls, fileobj: typing.BinaryIO):
+        return cls._read(fileobj, cls.SSHORT)
+
+    @classmethod
+    def read_uint(cls, fileobj: typing.BinaryIO):
+        return cls._read(fileobj, cls.UINT)
+
+    @classmethod
+    def read_int(cls, fileobj: typing.BinaryIO):
+        return cls._read(fileobj, cls.SINT)
+
+    @classmethod
+    def read_float(cls, fileobj: typing.BinaryIO):
+        return cls._read(fileobj, cls.FLOAT)
+
+    @classmethod
+    def read_ulong(cls, fileobj: typing.BinaryIO):
+        return cls._read(fileobj, cls.ULONG)
+
+    @classmethod
+    def read_pointer(cls, fileobj: typing.BinaryIO, fileheader):
+        """Read a pointer from a file.
+
+        The pointer size is given by the header (BlendFileHeader).
+        """
+
+        if fileheader.pointer_size == 4:
+            return cls.read_uint(fileobj)
+        if fileheader.pointer_size == 8:
+            return cls.read_ulong(fileobj)
+        raise ValueError('unsupported pointer size %d' % fileheader.pointer_size)
+
+
+class BigEndianTypes(LittleEndianTypes):
+    UCHAR = struct.Struct(b'>b')
+    USHORT = struct.Struct(b'>H')
+    USHORT2 = struct.Struct(b'>HH')  # two shorts in a row
+    SSHORT = struct.Struct(b'>h')
+    UINT = struct.Struct(b'>I')
+    SINT = struct.Struct(b'>i')
+    FLOAT = struct.Struct(b'>f')
+    ULONG = struct.Struct(b'>Q')
+
+
+def write_string(fileobj: typing.BinaryIO, astring: str, fieldlen: int):
+    assert isinstance(astring, str)
+    write_bytes(fileobj, astring.encode('utf-8'), fieldlen)
+
+
+def write_bytes(fileobj: typing.BinaryIO, data: bytes, fieldlen: int):
+    assert isinstance(data, (bytes, bytearray))
+    if len(data) >= fieldlen:
+        to_write = data[0:fieldlen]
+    else:
+        to_write = data + b'\0'
+
+    fileobj.write(to_write)
+
+
+def read_bytes0(fileobj, length):
+    data = fileobj.read(length)
+    return read_data0(data)
+
+
+def read_string(fileobj, length):
+    return fileobj.read(length).decode('utf-8')
+
+
+def read_string0(fileobj, length):
+    return read_bytes0(fileobj, length).decode('utf-8')
+
+
+def read_data0_offset(data, offset):
+    add = data.find(b'\0', offset) - offset
+    return data[offset:offset + add]
+
+
+def read_data0(data):
+    add = data.find(b'\0')
+    return data[:add]