hangshuo652
44 lines
1.5 KiB
Python
44 lines
1.5 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, path: str, tree: FieldTree) -> list[dict]:
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d = Path(path).read_bytes()
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rs = self._record_size(tree)
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if rs == 0 or len(d) == 0:
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return []
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return [self._parse(d[o:o + rs], tree) for o in range(0, len(d), rs) if len(d[o:o + rs]) >= rs]
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def _record_size(self, tree):
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return max((f.offset + f.length for f in tree.fields), default=0)
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def _parse(self, r, tree):
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out = {}
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for n, f in tree.flatten().items():
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if f.length == 0 or f.offset + f.length > len(r):
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continue
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raw = r[f.offset:f.offset + f.length]
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if f.usage == "COMP-3":
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out[n] = self._comp3(raw, f.signed, f.decimal)
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elif f.usage in ("COMP", "COMP-5"):
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out[n] = int.from_bytes(raw, "big", signed=f.signed)
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else:
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out[n] = raw.decode("ascii", errors="replace").strip()
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return out
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def _comp3(self, raw, signed, dec):
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if not raw:
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return "0"
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nib = []
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for b in raw:
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nib.append((b >> 4) & 0xF)
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nib.append(b & 0xF)
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s = nib.pop()
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v = sum(n * (10 ** (len(nib) - i)) for i, n in zip(range(len(nib)), nib))
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if signed and s in (0xD, 0xB):
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v = -v
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d = 10 ** dec
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return f"{float(v) / d:.{dec}f}" if dec else str(v)
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