MICROLZMA DECOMPRESSOR(9)

🌸 MicroLZMA decompressor(9) 🌸

okay so this page is from the Kernel API Manual, bestie, and it's all about the MicroLZMA decompressor. very niche kernel lore, but we're gonna get through it together 💅✨

✨ DESCRIPTION ✨

So this MicroLZMA header format was created for use in EROFS, but it may be used by others too — it's not EROFS-only, periodt. But real talk:

In most cases one needs the XZ APIs above instead. 🚨

The compressed format supported by this decoder is a raw LZMA stream whose first byte (always 0x00) has been replaced with the bitwise-negation of the LZMA properties (lc/lp/pb) byte.

Example time, because yes: if lc/lp/pb is 3/0/2, the first byte is 0xA2. The way that works means the first byte can never be 0x00. Iconic, honestly 💖

Just like with LZMA2, lc + lp <= 4 must be true. No cap.

The LZMA end-of-stream marker must not be used 🚫.

The unused values are reserved for future use — so don't go inventing your own little meanings for them, bestie 🙈.

🔥 SEE ALSO 🔥

• Kernel file ./include/linux/xz.h
• enum xz_mode(9)
• enum xz_ret(9)
• struct xz_buf(9)
• xz_dec_init(9)
• xz_dec_run(9)
• xz_dec_reset(9)
• xz_dec_end(9)
• xz_dec_microlzma_alloc(9)
• xz_dec_microlzma_reset(9)
• xz_dec_microlzma_run(9)
• xz_dec_microlzma_end(9)

mwah 💋 — this page came from source ./include/linux and is dated October 2026; the footer/manual version is MicroLZMA decompressor(9). now go be iconic, bestie 🫶✨