60 lines
2.2 KiB
Markdown
60 lines
2.2 KiB
Markdown
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# wickra-c
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C ABI for [Wickra](https://github.com/wickra-lib/wickra) — streaming-first
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technical indicators with a Rust core. This crate is the **hub**: it compiles the
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core to a C-compatible shared/static library plus a generated header, so any
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C-capable language (C, C++, Go, C#, Java, R) links against one artifact instead
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of re-wiring every indicator natively.
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The native Python, Node, and WebAssembly bindings are unaffected — this is
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additive, for the ecosystems without first-class Rust tooling.
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## Artifacts
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```sh
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cargo build -p wickra-c --release
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```
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- `target/release/libwickra.{so,dylib}` / `wickra.dll` (+ `wickra.dll.lib` import lib on Windows)
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- `target/release/libwickra.a` / `wickra.lib` (static)
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- [`include/wickra.h`](include/wickra.h) — generated by cbindgen, committed.
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## API shape
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Each indicator is exposed as five `extern "C"` functions over an opaque handle:
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```c
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struct Sma *wickra_sma_new(uintptr_t period); /* NULL on bad params */
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double wickra_sma_update(struct Sma *h, double value); /* NaN during warmup */
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void wickra_sma_batch(struct Sma *h, const double *in, double *out, uintptr_t n);
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void wickra_sma_reset(struct Sma *h);
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void wickra_sma_free(struct Sma *h); /* exactly once per _new */
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```
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Conventions:
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- **Opaque handles.** `wickra_<ind>_new` returns a `T *` you must release with
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exactly one `wickra_<ind>_free`. There is no RAII across the boundary.
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- **NaN sentinel.** Scalar outputs return `NaN` while warming up or on a `NULL`
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handle, mirroring the other bindings — no error codes for the common path.
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- **Caller-owned batch buffers.** `wickra_<ind>_batch` writes one output per
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input into a buffer you provide; nothing is allocated across the boundary.
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- **NULL-safe.** Every function tolerates a `NULL` handle without crashing.
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## Header regeneration
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The header is generated and committed; CI checks it is in sync:
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```sh
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cbindgen --config bindings/c/cbindgen.toml --crate wickra-c --output bindings/c/include/wickra.h
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```
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## Examples
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Runnable C examples (build via CMake or a direct compiler invocation) live in
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[`examples/c`](../../examples/c).
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## License
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`MIT OR Apache-2.0`, the same as the rest of Wickra.
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