lz4_Frame_format.md: document kernel legacy last block #1634
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Since torvalds/linux@2c48441, the Linux Kernel is able to discern the end of a legacy LZ4 frame by the presence of four 0 bytes, parsed as a B.CSize of 0 in the decoder. This is originally intended to make it mix well with grub initrd concatenation behavior (which uses a clause in the initramfs format about allowing arbitrary zero paddings), but I think it is a pretty good idea for any application limited to the legacy format in general.
Cyan4973
approved these changes
Jul 21, 2025
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Since torvalds/linux@2c48441, the Linux Kernel is able to discern the end of a legacy LZ4 frame by the presence of four 0 bytes, parsed as a B.CSize of 0 in the decoder. This is originally intended to make it mix well with grub initrd concatenation behavior (which uses a clause in the initramfs format about allowing arbitrary zero paddings), but I think it is a pretty good idea for any application limited to the legacy format in general.