feat: init the repo

fuzz/Cargo.toml

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+[package]
+name = "ferro_ta_fuzz"
+version = "0.0.1"
+edition = "2021"
+publish = false
+
+# Exclude from the root workspace so cargo doesn't reject it as an unlisted member
+[workspace]
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+libfuzzer-sys = "0.4"
+ferro_ta_core = { path = "../crates/ferro_ta_core" }
+
+[[bin]]
+name = "fuzz_sma"
+path = "fuzz_targets/fuzz_sma.rs"
+test = false
+doc = false
+bench = false
+
+[[bin]]
+name = "fuzz_rsi"
+path = "fuzz_targets/fuzz_rsi.rs"
+test = false
+doc = false
+bench = false
+
+[profile.release]
+debug = 1

fuzz/fuzz_targets/fuzz_rsi.rs

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+/*!
+Fuzz target for `ferro_ta_core::momentum::rsi`.
+
+Generates arbitrary f64 slices (via raw bytes) and arbitrary timeperiods,
+verifying that RSI never panics and that all finite output values lie in
+the range [0, 100].
+*/
+
+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use ferro_ta_core::momentum;
+
+fuzz_target!(|data: &[u8]| {
+    // Need at least 1 byte for timeperiod + 8 bytes for one f64
+    if data.len() < 2 {
+        return;
+    }
+
+    // Extract timeperiod from first byte (1-64)
+    let timeperiod = ((data[0] as usize) % 64) + 1;
+
+    // Interpret remaining bytes as f64 values
+    let float_bytes = &data[1..];
+    let n_floats = float_bytes.len() / 8;
+    if n_floats == 0 {
+        return;
+    }
+
+    let close: Vec<f64> = (0..n_floats)
+        .map(|i| {
+            let chunk: [u8; 8] = float_bytes[i * 8..(i + 1) * 8].try_into().unwrap();
+            f64::from_le_bytes(chunk)
+        })
+        .collect();
+
+    // Must not panic
+    let result = momentum::rsi(&close, timeperiod);
+
+    // Result length must match input
+    assert_eq!(result.len(), close.len(), "RSI output length mismatch");
+
+    // All finite output values must be in [0, 100]
+    for (i, &v) in result.iter().enumerate() {
+        if v.is_finite() {
+            assert!(
+                v >= 0.0 && v <= 100.0,
+                "RSI result[{i}] = {v} is out of [0, 100]"
+            );
+        }
+    }
+});

fuzz/fuzz_targets/fuzz_sma.rs

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+/*!
+Fuzz target for `ferro_ta_core::overlap::sma`.
+
+The fuzzer generates arbitrary byte sequences and interprets them as
+`f64` values plus a `timeperiod`.  The invariant under test is that the
+function **never panics** for any input — it may return `NaN`, `Inf`, or
+an all-NaN slice, but it must not crash.
+*/
+
+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use ferro_ta_core::overlap;
+
+fuzz_target!(|data: &[u8]| {
+    // Need at least 1 byte for timeperiod + 8 bytes for one f64
+    if data.len() < 2 {
+        return;
+    }
+
+    // Extract timeperiod from first byte (1-64 to keep runs fast)
+    let timeperiod = ((data[0] as usize) % 64) + 1;
+
+    // Interpret remaining bytes as f64 values (skip incomplete trailing bytes)
+    let float_bytes = &data[1..];
+    let n_floats = float_bytes.len() / 8;
+    if n_floats == 0 {
+        return;
+    }
+
+    let close: Vec<f64> = (0..n_floats)
+        .map(|i| {
+            let chunk: [u8; 8] = float_bytes[i * 8..(i + 1) * 8].try_into().unwrap();
+            f64::from_le_bytes(chunk)
+        })
+        .collect();
+
+    // Must not panic for any input
+    let result = overlap::sma(&close, timeperiod);
+
+    // Result length must match input length
+    assert_eq!(result.len(), close.len(), "SMA output length mismatch");
+
+    // The first (timeperiod - 1) values must be NaN
+    for i in 0..(timeperiod.min(close.len()).saturating_sub(1)) {
+        assert!(
+            result[i].is_nan(),
+            "SMA result[{i}] should be NaN (warm-up period)"
+        );
+    }
+});