inditrans

A transliteration library for Indic/Brahmic and Latin scripts, implemented as a C++23 engine compiled to a shared library (native) and WASM (Web/Node.js). The same phoneme-level pipeline is exposed to Flutter/Dart and JavaScript/TypeScript.

• No server required. FFI (native) or WASM (Web/Node.js) for near-native performance.
• ITRANS toggle transliteration — wrap any region in ##…## to pass it through unchanged.
• XML/HTML tag pass-through — tags are never transliterated.
• Special handling for Tamil, Malayalam, Gurmukhi, and other scripts tuned for readability.
• Vedic accent support for Vedic scriptures.

Supported scripts

Indic/Brahmic: Assamese, Bengali, Burmese, Devanagari, Gujarati, Gurmukhi, Kannada, Khmer, Malayalam, Oriya, Sinhala, Tamil, Tamil-Extended, Telugu, Thai, Tibetan

Standard Latin notations: IAST · IPA · ISO 15919 · ITRANS · TITUS · Harvard-Kyoto · Velthuis · SLP1 · WX

Custom Latin notations: ReadableLatin

ITRANS notation notes

inditrans implements uniform phonemic vowel mapping adhering to the ITRANS specification:

• Short vowels: e and o encode short vowels across all scripts (e.g. Kannada ಎ / ೆ, Telugu ఎ / ె, Tamil எ / ெ, Malayalam എ / െ, Devanagari ऎ / ॆ). The legacy markers ^e and ^o remain supported as aliases for e and o.
• Long vowels: E and O encode long vowels (e.g. Kannada ಏ / ೇ, Telugu ఏ / ే, Tamil ஏ / ே, Malayalam ഏ / േ, Devanagari ए / े). ee and oo also continue to represent long vowels where standard.
• Examples:
  • te $\to$ तॆ / ತೆ (short e); tE $\to$ ते / ತೇ (long e)
  • to $\to$ तॊ / ತೊ (short o); tO $\to$ तो / ತೋ (long o)
  • tere bina $\to$ ತೆರೆ ಬಿನ (Kannada), तॆरॆ बिन (Devanagari)
  • tErE bina $\to$ ತೇರೇ ಬಿನ (Kannada), तेरे बिन (Devanagari)

Distributions

Platform	Package	Install
Flutter / Dart	pub.dev/packages/inditrans	flutter pub add inditrans
Node.js / Browser	npmjs.com/@vm75/inditrans	npm install @vm75/inditrans

Repository layout

flutter/    Flutter FFI plugin (Dart + C++ shared library + WASM)
nodejs/     TypeScript/JavaScript package (WASM via Emscripten)
js/         WASM build output consumed by nodejs/
native/     Canonical C++23 engine (source, tests, CLI, and benchmarks)
tool/       Code-generation utilities (script data, bindings, version bump)
test-files/ Shared test-case JSON used by all distributions

Building and testing

make all          # build native CLI, WASM, and Flutter plugin
make test         # run C++ native tests
make testall      # run native, Flutter, and Node.js tests
make bench-all    # run the native benchmark summary
make dll          # cross-compile Windows x86-64 DLL using MinGW-w64
make validate     # validate version consistency and changelog

Requires: CMake ≥ 3.20, Clang/LLVM ≥ 17 (or C++23-capable compiler), Emscripten 6.0.10, Flutter ≥ 3.38.10 / Dart ≥ 3.10.8, Node.js ≥ 18.3 / Yarn.

See platform support for the declared platform matrix, tested toolchains, and current acceptance evidence.

Performance benchmarking

The native benchmark suite measures throughput (MB/s and ns/call), per-call latency, output-size expansion, and—on Linux with glibc—heap allocation events, requested allocation bytes, peak requested live bytes, and bytes still live after the measured call.

make bench-all          # run all available benchmarks and print a formatted summary
make bench              # throughput benchmark (10 cases × 3 approximate target sizes)
make bench-short        # per-call latency benchmark, including result destruction
make output-size-bench  # report input/output bytes and expansion ratio
make mem-bench          # backward-compatible alias for output-size-bench
make bench-alloc-linux  # Linux/glibc allocation probe

The allocator probe is optional. bench-all, bench-save, and bench-compare still run on other platforms and skip allocation metrics instead of failing during setup.

To compare an optimization against a saved baseline:

make bench-save                         # capture baseline metrics before making changes
# ... make changes ...
make bench-compare                      # report changes; always fails on output-hash mismatch
BENCH_STRICT=1 make bench-compare       # also fail on regressions at or above the threshold

bench-compare validates the FNV-1a output hash for every throughput and short-call case before treating timing changes as meaningful. Performance regressions are flagged at 5% by default; override the threshold with BENCH_REGRESSION_THRESHOLD=<percent>.

Windows DLL cross-compilation (Linux → Windows)

To cross-compile the 64-bit Windows shared library (inditrans.dll) from Linux:

sudo apt-get install mingw-w64 cmake
make dll

• Target: Windows x86-64 (inditrans.dll), copied to flutter/example.dart/inditrans.dll.
• Toolchain: Cross-compiled using MinGW-w64 (x86_64-w64-mingw32-g++) with CMake toolchain tool/cmake/mingw64.cmake.
• Language standard: Enforces C++23 internally (GCC ≥ 13).
• Public ABI: Plain C interface (extern "C") exposing transliterate, isScriptSupported, and releaseBuffer. No C++ types (std::string, STL containers, exceptions) cross the boundary, ensuring full compatibility with MSVC callers, Dart FFI, and other runtimes.
• Runtime dependencies: Linked with -static-libgcc -static-libstdc++ to eliminate MinGW C++ runtime DLL dependencies (libstdc++-6.dll, libgcc_s_seh-1.dll).

Documentation

• Flutter package README
• Node.js package README
• Engine architecture
• Consolidated changelog
• Release process
• Agent guide

License

MIT