From 9fde94d068f87b34e0bc6bfa48388d89bb54f1e4 Mon Sep 17 00:00:00 2001
From: salmonik <salmonik@tuta.io>
Date: Mon, 3 Aug 2026 02:23:35 +0200
Subject: v0.5.8: heap-free QR encoder + crash-dump QR on framebuffer
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Real hardware has no serial console, so a kernel crash only leaves a
frozen screen.  Every dump_lines() report now also renders the crash
text as a scannable QR below the white-on-red band (photograph the
screen instead of relaying text).

- rsnix/src/qr.rs: from-scratch no_std/no_alloc byte-mode QR encoder
  (EC-L, v1..v40, .bss statics only — safe on the fault path):
  RS over GF(256), codeword interleave, zigzag placement, 8 masks with
  N1-N4 penalty auto-selection, format/version info.
- gop.rs: dump_qr() joins dump lines into a static buffer, truncates
  with '...' at the v40-L capacity, encodes, and renders centered
  black-on-white with a 4-module quiet zone.
- tools/qrcheck: host harness (embedds qr.rs) + qrcheck.py cross-check
  against segno's placement primitives.  Verified bit-exact: 12
  versions x 8 masks forced, plus auto-mask choice matches segno's
  penalty evaluation.  Caught 3 encoder bugs (multi-block interleave
  offsets, transposed version info, mask eval ordering).
- QEMU e2e: page-fault dump screendump decodes via zbarimg, content
  matches the serial log line-for-line.
- test-msg.sh and test-fault.sh both PASS; debug+release 0 warnings.
---
 tools/qrcheck/.gitignore  |  1 +
 tools/qrcheck/Cargo.lock  |  7 ++++++
 tools/qrcheck/Cargo.toml  | 13 +++++++++++
 tools/qrcheck/src/main.rs | 58 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 79 insertions(+)
 create mode 100644 tools/qrcheck/.gitignore
 create mode 100644 tools/qrcheck/Cargo.lock
 create mode 100644 tools/qrcheck/Cargo.toml
 create mode 100644 tools/qrcheck/src/main.rs

(limited to 'tools/qrcheck')

diff --git a/tools/qrcheck/.gitignore b/tools/qrcheck/.gitignore
new file mode 100644
index 0000000..ea8c4bf
--- /dev/null
+++ b/tools/qrcheck/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/tools/qrcheck/Cargo.lock b/tools/qrcheck/Cargo.lock
new file mode 100644
index 0000000..141dd97
--- /dev/null
+++ b/tools/qrcheck/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "qrcheck"
+version = "0.1.0"
diff --git a/tools/qrcheck/Cargo.toml b/tools/qrcheck/Cargo.toml
new file mode 100644
index 0000000..4d4487c
--- /dev/null
+++ b/tools/qrcheck/Cargo.toml
@@ -0,0 +1,13 @@
+[package]
+name = "qrcheck"
+version = "0.1.0"
+edition = "2024"
+
+[[bin]]
+name = "qrcheck"
+path = "src/main.rs"
+
+[profile.release]
+panic = "abort"
+
+[workspace]
diff --git a/tools/qrcheck/src/main.rs b/tools/qrcheck/src/main.rs
new file mode 100644
index 0000000..d294485
--- /dev/null
+++ b/tools/qrcheck/src/main.rs
@@ -0,0 +1,58 @@
+//! Host-side cross-check tool for the kernel QR encoder.
+//!
+//! Usage: `qrcheck TEXT [VERSION] [MASK]`
+//!   - with VERSION+MASK: force both and dump the matrix (compared against
+//!     segno by `tools/qrcheck.py`);
+//!   - with neither: auto-pick version and best mask, print `v<ver> m<mask>`.
+//!
+//! Output: first line `v<N> m<N|999>`, then one line per matrix row of
+//! `#` (dark) / `.` (light).
+#![allow(static_mut_refs)]
+
+#[path = "../../../rsnix/src/qr.rs"]
+mod qr;
+
+fn main() {
+    let args: Vec<String> = std::env::args().collect();
+    if args.get(1).map(String::as_str) == Some("--raw") {
+        let text = args.get(2).map(String::as_str).unwrap_or("hello");
+        let version: usize = args.get(3).and_then(|s| s.parse().ok()).unwrap_or(0);
+        let v = if version > 0 {
+            qr::encode_at(text.as_bytes(), version, Some(0))
+        } else {
+            qr::encode(text.as_bytes())
+        };
+        if v == 0 {
+            eprintln!("FAIL");
+            std::process::exit(1);
+        }
+        for b in qr::codeword_stream() {
+            print!("{:02x}", b);
+        }
+        println!();
+        return;
+    }
+    let text = args.get(1).map(String::as_str).unwrap_or("hello world");
+    let version: usize = args.get(2).and_then(|s| s.parse().ok()).unwrap_or(0);
+    let mask: Option<usize> = args.get(3).and_then(|s| s.parse().ok());
+
+    let v = if version > 0 {
+        qr::encode_at(text.as_bytes(), version, mask)
+    } else {
+        qr::encode(text.as_bytes())
+    };
+    if v == 0 {
+        eprintln!("FAIL: cannot encode {} bytes at v{}", text.len(), version);
+        std::process::exit(1);
+    }
+    let size = qr::size();
+    let m = if let Some(m) = mask { m } else { qr::last_mask() };
+    println!("v{} m{}", v, m);
+    for y in 0..size {
+        let mut row = String::with_capacity(size);
+        for x in 0..size {
+            row.push(if qr::module(x, y) { '#' } else { '.' });
+        }
+        println!("{}", row);
+    }
+}
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