djvudec — a plain-C DjVu decoder

This is a djvu format decoder, like libdjvu, but better:

• smaller bun cmd/compare-code-sizes.ts shows 100 kB (us) vs. 720 kB of libdjvue
• plain C, no dependencies (vs. C++)
• simpler API
• simpler to integrate: copy dist/djvu.h and dist/djvu.c into your project. This is amalgamated src/* into a single file, like sqlite
• mostly faster, according to benchmarks (bun cmd/bench.ts)
• tested on thousands of .djvu files for bit-by-bit correctness to libdjvu

See src/djvu.h. Sketch:

djvu_init();                                       /* once, before threads */
djvu_ctx *ctx = djvu_ctx_new(NULL, NULL, NULL, NULL, on_error, NULL);
djvu_doc *doc = djvu_doc_open(ctx, data, len);     /* data must outlive doc */
int n = djvu_doc_page_count(doc);
djvu_page_info info; djvu_doc_page_info(doc, 0, &info);
djvu_image *img = djvu_page_render(doc, 0, 1);     /* gray8 / rgb24 */
char *txt = djvu_page_text(doc, 0);

Requires clang, bun, and git. cmd/get-deps.ts clones the DjvuNet, DjVuLibre, and DjvuNet/artifacts repos into deps/; the .djvu samples in those checkouts are the test corpus. build.ts and tests.ts call it automatically.

bun cmd/get-deps.ts     # clone deps (the corpus; auto-run below)
bun cmd/build.ts        # build reference tools + the C library and djvu_test.exe
bun cmd/tests.ts -all   # build, then verify render + text against DjVuLibre
bun cmd/fuzz.ts -check-crashes  # replay tracked fuzz/crashes under ASan (CI)

CI (GitHub Actions): .github/workflows/ci.yml — MSVC/Linux smoke + amalgamation, fuzz crash regression, WASM decode.

djvu_test CLI (jbig2dec-flavored):

djvu_test -info in.djvu
djvu_test -page N -out out.pgm in.djvu
djvu_test -page N -text in.djvu

This is automatic, ai assited port of of DjvuNet (C#) DjVu decoder, done with Grok Build.

Correctness is verified against DjVuLibre (ddjvu, djvutxt) on the sample files in deps/DjvuNet/Specs, and my own collection large collection of djvu files collected for testing SumatraPDF.