106 lines
2.9 KiB
Python
106 lines
2.9 KiB
Python
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import io
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import struct
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class Reader:
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def __init__(self, file, parent=None, indent=0):
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self.file = file
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self.size: int = 0
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self.size_pos = None
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self.parent = parent
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self.indent = " " * indent #for print debugging
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def __enter__(self):
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self.size_pos = self.file.tell()
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self.header = self.read_bytes(4).decode("utf-8")
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self.size = self.read_u32()
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padding_length = 4 - (self.size % 4) if self.size % 4 > 0 else 0
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self.end_pos = self.size_pos + padding_length + self.size + 8
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#print(self.indent + "Begin " + self.header + ", Size: " + str(self.size) + ", Pos: " + str(self.size_pos))
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return self
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def __exit__(self, exc_type, exc_value, traceback):
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if self.size > self.MAX_SIZE:
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raise OverflowError(f".msh file overflowed max size. size = {self.size} MAX_SIZE = {self.MAX_SIZE}")
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#print(self.indent + "End " + self.header)
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self.file.seek(self.end_pos)
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def read_bytes(self,num_bytes):
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return self.file.read(num_bytes)
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def read_string(self):
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last_byte = self.read_bytes(1)
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result = b''
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while last_byte[0] != 0x0:
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result += last_byte
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last_byte = self.read_bytes(1)
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return result.decode("utf-8")
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def read_i8(self, num=1):
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buf = self.read_bytes(num)
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result = struct.unpack(f"<{num}b", buf)
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return result[0] if num == 1 else result
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def read_u8(self, num=1):
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buf = self.read_bytes(num)
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result = struct.unpack(f"<{num}B", buf)
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return result[0] if num == 1 else result
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def read_i16(self, num=1):
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buf = self.read_bytes(num * 2)
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result = struct.unpack(f"<{num}h", buf)
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return result[0] if num == 1 else result
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def read_u16(self, num=1):
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buf = self.read_bytes(num * 2)
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result = struct.unpack(f"<{num}H", buf)
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return result[0] if num == 1 else result
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def read_i32(self, num=1):
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buf = self.read_bytes(num * 4)
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result = struct.unpack(f"<{num}i", buf)
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return result[0] if num == 1 else result
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def read_u32(self, num=1):
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buf = self.read_bytes(num * 4)
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result = struct.unpack(f"<{num}I", buf)
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return result[0] if num == 1 else result
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def read_f32(self, num=1):
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buf = self.read_bytes(num * 4)
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result = struct.unpack(f"<{num}f", buf)
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return result[0] if num == 1 else result
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def read_child(self):
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child = Reader(self.file, parent=self, indent=int(len(self.indent) / 2) + 1)
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return child
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def skip_bytes(self,num):
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self.file.seek(num,1)
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def peak_next_header(self):
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buf = self.read_bytes(4);
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self.file.seek(-4,1)
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return buf.decode("utf-8")
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def could_have_child(self):
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return self.end_pos - self.file.tell() >= 8
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MAX_SIZE: int = 2147483647 - 8
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