Compression,without a black box.

03 / Build & use

From source
to first frame.

The default build needs GNU Make and a C11 compiler. The codec uses the C standard library and has no third-party runtime dependency; optional threaded encoding is enabled explicitly.

• Buildmake produces the CLI. make amalg emits a drop-in vaptvupt.c and vaptvupt.h.
• Verifymake test runs C suites, negative cases, and the Python/JavaScript reference checks when their runtimes are available.
• Window-w 10..24 selects 1 KiB through 16 MiB; zero/omitted keeps automatic selection.
• FilesThe CLI writes .zupt by default and still recognizes legacy .vv frames by their header.

git clone https://codeberg.org/berkeley/vaptvupt-codec.git
cd vaptvupt-codec
git checkout v2.65.11
make
make test

./vaptvupt -c -m fast -o fast.zupt input
./vaptvupt -c -m balanced -o data.zupt input
./vaptvupt -c -m extreme -o dense.zupt input
./vaptvupt -d -o restored data.zupt

#include "vaptvupt.h"

vv_options_t opt;
vv_default_options(&opt);
opt.mode = VV_MODE_BALANCED;

size_t cap = vv_compress_bound(src_len);
int64_t n = vv_compress(src, src_len, dst, cap, &opt);
if (n < 0) { /* handle VV_ERR_* */ }

int64_t m = vv_decompress(dst, (size_t)n, out, out_cap);
if (m < 0) { /* reject the frame */ }

04 / Format & filters

Portable bits.
Optional transforms.

A frame starts with a 16-byte header, continues with independently typed blocks, and may end with an XXH64 footer. The public specification is sufficient to write a decoder without importing the C implementation.

Optional reversible BCJ preprocessing can normalize x86 branch targets or AArch64 BL/ADRP instructions before compression. It can improve executable-code ratio on suitable binaries; it is not encryption and does not change the security boundary.

# x86 executable code
./vaptvupt -c -m extreme --bcj -o app.zupt app

# AArch64 executable code
./vaptvupt -c -m extreme --bcj-arm64 -o app.zupt app

# Detect ELF / PE / Mach-O and select one or none
./vaptvupt -c --auto-filter -o app.zupt app