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⚡ Bolt: Optimize yEnc decoding >60x #23

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⚡ Bolt: Optimize yEnc decoding >60x #23

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1 change: 1 addition & 0 deletions .gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -5,3 +5,4 @@ config.ini
*.txt
.*
!.gitignore
__pycache__/
25 changes: 15 additions & 10 deletions verify_nzb.py
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Original file line number Diff line number Diff line change
Expand Up @@ -115,19 +115,24 @@ def _parse_yenc_attrs(line: bytes) -> dict[str, str]:
return attrs


_DECODE_TABLE = bytes((i - 42) % 256 for i in range(256))
_ESCAPED_DECODE_TABLE = bytes((i - 106) % 256 for i in range(256))

def _decode_yenc_lines(lines: Iterable[bytes]) -> bytes:
decoded = bytearray()
for line in lines:
index = 0
while index < len(line):
byte = line[index]
if byte == 61:
index += 1
if index >= len(line):
raise ValueError("dangling yEnc escape")
byte = (line[index] - 64) % 256
decoded.append((byte - 42) % 256)
index += 1
if b"=" not in line:
decoded.extend(line.translate(_DECODE_TABLE))
continue

parts = line.split(b"=")
decoded.extend(parts[0].translate(_DECODE_TABLE))
for part in parts[1:]:
if not part:
raise ValueError("dangling yEnc escape")
Comment on lines +131 to +132
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@chatgpt-codex-connector chatgpt-codex-connector Bot May 27, 2026

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P1 Badge Preserve consecutive yEnc escape markers during decode

The new split(b"=") logic misclassifies consecutive escape markers as a dangling escape: for input like b"==" (or any segment containing "=="), parts includes an empty chunk and if not part: raise ValueError(...) now triggers. In yEnc decoding, = should consume the very next byte (which may itself be =), so this is a behavioral regression from the previous byte-wise parser and can incorrectly flag decodable payloads as corrupt.

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decoded.append(_ESCAPED_DECODE_TABLE[part[0]])
if len(part) > 1:
decoded.extend(part[1:].translate(_DECODE_TABLE))
return bytes(decoded)


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