Don't allocate a Vec to pad with zeros. #473

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qm3ster wants to merge 2 commits from qm3ster/patch-1 into master

qm3ster commented

2025-07-30 16:40:20 +00:00

(Migrated from github.com)

Might be worth it not to use uefi::fs::FileSystem::read, because it:

returns an exactly info.file_size() sized Vec, so it reallocates the whole file on any padding
zeroes the memory first
doesn't align start (not sure how to fix this without unsafe, not sure if it has benefits either)

Instead, one Vec<u8> (or unsafe buffer) could be preallocated for kernel+pad+initrd+(pad+initrdN)* by iterating the metadata first, which the above method does internally, and then RegularFile::read used.

Might be worth it not to use `uefi::fs::FileSystem::read`, because it: 1. returns an exactly `info.file_size()` sized `Vec`, so it reallocates the whole file on any padding 2. zeroes the memory first 3. doesn't align start (not sure how to fix this without unsafe, not sure if it has benefits either) Instead, one `Vec<u8>` (or unsafe buffer) could be preallocated for kernel+pad+initrd+(pad+initrdN)* by iterating the metadata first, which the above method does internally, and then `RegularFile::read` used.

RaitoBezarius (Migrated from github.com) approved these changes

2025-07-31 00:50:33 +00:00

RaitoBezarius (Migrated from github.com) left a comment

Sounds good to me.
Testing is needed before merge.

Sounds good to me. Testing is needed before merge.

raito force-pushed qm3ster/patch-1 from 5429e7b36b to 52fb329d1f

2025-08-03 16:28:44 +00:00

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raito force-pushed qm3ster/patch-1 from 52fb329d1f to 30c949c07c

2025-08-03 16:30:39 +00:00

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