hangshuo652
57 lines
2.0 KiB
Python
57 lines
2.0 KiB
Python
import struct
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from pathlib import Path
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from data.field_tree import FieldTree
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class CobolBinaryReader:
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def read(self, binary_path: str, tree: FieldTree) -> list[dict]:
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data = Path(binary_path).read_bytes()
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record_size = self._compute_record_size(tree)
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if record_size == 0 or len(data) == 0:
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return []
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records = []
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for offset in range(0, len(data), record_size):
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record = data[offset:offset + record_size]
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if len(record) >= record_size:
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records.append(self._parse_record(record, tree))
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return records
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def _compute_record_size(self, tree: FieldTree) -> int:
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max_end = 0
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for f in tree.fields:
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end = f.offset + f.length
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if end > max_end:
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max_end = end
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return max_end
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def _parse_record(self, record: bytes, tree: FieldTree) -> dict:
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result = {}
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for name, field in tree.flatten().items():
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if field.length == 0 or field.offset + field.length > len(record):
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continue
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raw = record[field.offset:field.offset + field.length]
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if field.usage == "COMP-3":
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result[name] = self._parse_comp3(raw, field.signed, field.decimal)
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elif field.usage == "COMP" or field.usage == "COMP-5":
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result[name] = int.from_bytes(raw, "big", signed=field.signed)
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else:
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result[name] = raw.decode("ascii", errors="replace").strip()
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return result
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def _parse_comp3(self, raw: bytes, signed: bool, decimal: int) -> str:
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if not raw:
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return "0"
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nibbles = []
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for b in raw:
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nibbles.append((b >> 4) & 0x0F)
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nibbles.append(b & 0x0F)
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sign = nibbles.pop()
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value = 0
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for n in nibbles:
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value = value * 10 + n
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if signed and sign in (0x0D, 0x0B):
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value = -value
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divisor = 10 ** decimal
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result = float(value) / divisor
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return f"{result:.{decimal}f}" if decimal else str(value)
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