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Multi part reverse lookup #59

Merged
merged 7 commits into from
Apr 18, 2024
Merged

Multi part reverse lookup #59

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65f1bbf
Update magic_data.json with .ctm, .pt2, .mlt
NebularNerd Mar 3, 2024
a557bd5
Update main.py with reverse lookup
NebularNerd Mar 3, 2024
ed74e52
Update main.py reformat to hopefully pass build tests
NebularNerd Mar 7, 2024
284daa4
Update main.py layout fixing using Black
NebularNerd Mar 7, 2024
1a98717
Update main.py pythonic fixes
NebularNerd Mar 12, 2024
463e013
Update main.py again
NebularNerd Mar 12, 2024
1c7d0f8
Merge branch 'develop' into Multi-part-reverse-lookup
NebularNerd Apr 8, 2024
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14 changes: 13 additions & 1 deletion puremagic/magic_data.json
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -89,6 +89,15 @@
"52494658": [
["4647444d", 8, ".dcr", "", "Adobe Shockwave"],
["4d563933", 8, ".dir", "", "Macromedia Director file format"]
],
"4352454d" : [
["444f4e4500000000", -8, ".ctm", "", "CreamTracker module"]
],
"3c747261636b206e616d653d22" : [
["3c2f747261636b3e0a", -9, ".pt2", "", "PicaTune 2 module"]
],
"3c6d6c74" : [
["3c2f6d6c743e0a", -7, ".mlt", "", "Shotcut project"]
]
},
"footers": [
Expand Down Expand Up @@ -1330,6 +1339,9 @@
["6674797068656973", 4, ".heic", "image/heic", "HEIC Image format (HEIS scalable)"],
["667479706865696d", 4, ".heic", "image/heic", "HEIC Image format (HEIM multiview)"],
["667479706865766d", 4, ".heic", "image/heic", "HEIC Animated Image format (HEIM multiview)"],
["6674797068657673", 4, ".heic", "image/heic", "HEIC Animated Image format (HEIS scalable)"]
["6674797068657673", 4, ".heic", "image/heic", "HEIC Animated Image format (HEIS scalable)"],
["4352454D", 44, ".ctm", "", "CreamTracker module"],
["3c747261636b206e616d653d22", 0, ".pt2", "", "PicaTune 2 module"],
["3c6d6c74", 38, ".mlt", "", "Shotcut project"]
]
}
41 changes: 28 additions & 13 deletions puremagic/main.py
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Original file line number Diff line number Diff line change
Expand Up @@ -151,20 +151,35 @@ def _identify_all(header: bytes, footer: bytes, ext=None) -> List[PureMagicWithC
for matched in matches:
if matched.byte_match in multi_part_header_dict:
for magic_row in multi_part_header_dict[matched.byte_match]:
start = magic_row.offset
end = magic_row.offset + len(magic_row.byte_match)
if end > len(header):
continue
if header[start:end] == magic_row.byte_match:
new_matches.add(
PureMagic(
byte_match=header[matched.offset : end],
offset=magic_row.offset,
extension=magic_row.extension,
mime_type=magic_row.mime_type,
name=magic_row.name,
if "-" in str(magic_row.offset):
start = magic_row.offset
end = magic_row.offset + len(magic_row.byte_match)
match_area = footer[start:end] if end != 0 else footer[start:]
if match_area == magic_row.byte_match:
new_matches.add(
PureMagic(
byte_match=matched.byte_match + magic_row.byte_match,
offset=magic_row.offset,
extension=magic_row.extension,
mime_type=magic_row.mime_type,
name=magic_row.name,
)
)
else:
start = magic_row.offset
end = magic_row.offset + len(magic_row.byte_match)
if end > len(header):
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Suggested change
if "-" in str(magic_row.offset):
start = magic_row.offset
end = magic_row.offset + len(magic_row.byte_match)
match_area = footer[start:end] if end != 0 else footer[start:]
if match_area == magic_row.byte_match:
new_matches.add(
PureMagic(
byte_match=matched.byte_match + magic_row.byte_match,
offset=magic_row.offset,
extension=magic_row.extension,
mime_type=magic_row.mime_type,
name=magic_row.name,
)
)
else:
start = magic_row.offset
end = magic_row.offset + len(magic_row.byte_match)
if end > len(header):
start = magic_row.offset
end = magic_row.offset + len(magic_row.byte_match)
if magic_row.offset < 0:
match_area = footer[start:end] if end != 0 else footer[start:]
if match_area == magic_row.byte_match:
new_matches.add(
PureMagic(
byte_match=matched.byte_match + magic_row.byte_match,
offset=magic_row.offset,
extension=magic_row.extension,
mime_type=magic_row.mime_type,
name=magic_row.name,
)
)
else:
if end > len(header):

Haven't verified the logic / tested myself but just wanted to provide a bit of python specific cleanup. Moving the start and end outside the if statements as they are the same, and check magic_row.offset < 0 instead of against a string (if that's a problem for some reason let me know.)

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@NebularNerd NebularNerd Mar 12, 2024 •
edited
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@cdgriffith, Tested and no issues, I have merged it into the PR. Thanks for the suggestions, my coding skills are ok but I know there's always room for improvement. 🙂

I used a str() as I had brain fog and skipped past the correct < 0 method, both achieve the same goal, just mine was the long way round. 🤣

continue
if header[start:end] == magic_row.byte_match:
new_matches.add(
PureMagic(
byte_match=header[matched.offset : end],
offset=magic_row.offset,
extension=magic_row.extension,
mime_type=magic_row.mime_type,
name=magic_row.name,
)
)
)

matches.extend(list(new_matches))
return _confidence(matches, ext)
Expand Down