Forum Discussion
Helper IFailure extracting files from large zip archives in ZIP64 format
here's how the central directory looks like
It starts at 61c63f46
Note that we are still talking unsigned 32 bit integers here. The only indication that this may be ZIP64 seems to be the FF instead of 00. The bad news is that all these FFFFFFFF are in the place where the file sizes are supposed to be. The actual file sizes (compressed and uncompressed) are nowhere to be seen.
Now, the compressed file size can be calculated under the assumption that the ZIP only includes one file. This would make the extraction possible if the ZIP file stays within the 32 bit limits (4GiB) but it would likely break down for files larger than that.
I updated my blog entry with a modified function that can read your sample file successfully.
Super Userhere's how the central directory looks like
It starts at 61c63f46
Note that we are still talking unsigned 32 bit integers here. The only indication that this may be ZIP64 seems to be the FF instead of 00. The bad news is that all these FFFFFFFF are in the place where the file sizes are supposed to be. The actual file sizes (compressed and uncompressed) are nowhere to be seen.
Now, the compressed file size can be calculated under the assumption that the ZIP only includes one file. This would make the extraction possible if the ZIP file stays within the 32 bit limits (4GiB) but it would likely break down for files larger than that.
I updated my blog entry with a modified function that can read your sample file successfully.
