kingchenc
91e05e3c26
## What
Introduces `wickra-c` — a `cdylib` + `staticlib` that exposes the Rust core over a **C ABI**. This is the hub every C-capable language (C, C++, Go, C#, Java, R) links against, instead of re-wiring each indicator natively. The native Python/Node/WASM bindings are untouched; this is purely additive, for ecosystems without first-class Rust tooling.
## Scope (foundation slice)
This PR deliberately validates the **whole pipeline end to end with one indicator (SMA)** before scaling to all 514, so the CI / cross-OS / header-drift mechanics are proven green first.
- Opaque `*mut T` handles; `wickra_<ind>_{new,update,batch,reset,free}`.
- NaN sentinel for warmup / NULL handles; caller-owned batch buffers; every function NULL-safe.
- cbindgen generates and commits `bindings/c/include/wickra.h` with opaque handle typedefs.
- A C smoke example (`examples/c/`) links the header + compiled library and runs (CMake + ctest).
- A `c-abi` CI job builds the library and runs the smoke test on **Linux, macOS and Windows**, plus a header drift check on Linux.
## Notes
- The per-indicator FFI blocks are plain `#[no_mangle]` functions, **not** a macro: cbindgen cannot see macro-generated functions on stable Rust (macro expansion needs nightly), so the blocks are written literally and will be generated mechanically by the ScriptHelpers `capi` wrapper in a follow-up (same model as the committed-but-generated Node `index.js`).
- `bindings/c` cannot inherit the workspace `forbid(unsafe_code)` lint (the C boundary needs raw pointers), so it mirrors every workspace lint and only relaxes `unsafe_code`. The Rust core stays `unsafe`-forbidden.
## Follow-ups (separate PRs)
- ScriptHelpers `capi` generator + wire the scalar family (~235).
- Hand-written blocks for multi-output / custom-input / bars (~279).
- Docs consistency wave (README / docs / webpage: Python·Node·WASM·Rust → +C).
- Release wiring (native-lib matrix + header/lib GH-release assets) — gated.
37 lines
1.2 KiB
C
37 lines
1.2 KiB
C
/* Streaming usage example for the Wickra C ABI.
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*
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* The same five-function shape (new / update / batch / reset / free) drives every
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* scalar indicator. Here an EMA consumes a live tick stream one value at a time;
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* `update` is O(1) per tick and returns NaN until the indicator has warmed up.
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*
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* Build (after `cargo build -p wickra-c --release`):
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* cc examples/c/streaming.c -I bindings/c/include -L target/release -lwickra -lm -o streaming
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*/
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#include "wickra.h"
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#include <stdio.h>
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int main(void) {
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struct Ema *ema = wickra_ema_new(5);
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if (ema == NULL) {
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fprintf(stderr, "failed to create EMA\n");
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return 1;
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}
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const double prices[] = {10.0, 10.5, 11.0, 10.8, 11.2, 11.5, 11.3, 11.8};
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const size_t n = sizeof(prices) / sizeof(prices[0]);
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printf("EMA(5) streaming:\n");
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for (size_t i = 0; i < n; ++i) {
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double value = wickra_ema_update(ema, prices[i]);
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if (value != value) { /* NaN during warmup */
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printf(" tick %zu price %.2f -> (warming up)\n", i, prices[i]);
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} else {
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printf(" tick %zu price %.2f -> %.4f\n", i, prices[i], value);
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}
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}
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wickra_ema_free(ema);
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return 0;
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}
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