Add some basic fuzzing

Author: morr0ne

fuzz/.gitignore

@@ -0,0 +1,4 @@
+target
+corpus
+artifacts
+coverage

fuzz/Cargo.lock

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+[package]
+name = "sap-fuzz"
+version = "0.0.0"
+publish = false
+edition = "2024"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+libfuzzer-sys = "0.4"
+
+[dependencies.sap]
+path = ".."
+
+[[bin]]
+name = "parser_garbage"
+path = "fuzz_targets/parser_garbage.rs"
+test = false
+doc = false
+bench = false
+
+[[bin]]
+name = "raw_bytes"
+path = "fuzz_targets/raw_bytes.rs"
+test = false
+doc = false
+bench = false
+
+[[bin]]
+name = "from_env"
+path = "fuzz_targets/from_env.rs"
+test = false
+doc = false
+bench = false

fuzz/Cargo.toml

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+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use sap::Parser;
+
+fuzz_target!(|data: &[u8]| {
+    let byte_args: Vec<String> = data.iter().map(|&b| format!("{}", b as char)).collect();
+    let mut args = vec!["fuzz"];
+    args.extend(byte_args.iter().map(|s| s.as_str()));
+
+    if let Ok(mut parser) = Parser::from_arbitrary(args) {
+        while let Ok(Some(_)) = parser.forward() {
+            let _ = parser.value();
+        }
+    }
+
+    let null_string = String::from_utf8_lossy(data);
+    let null_split: Vec<&str> = null_string.split('\0').collect();
+    let mut args = vec!["fuzz"];
+    args.extend(null_split);
+
+    if let Ok(mut parser) = Parser::from_arbitrary(args) {
+        while let Ok(Some(_)) = parser.forward() {
+            let _ = parser.value();
+        }
+    }
+});

fuzz/fuzz_targets/parser_garbage.rs

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+#![no_main]
+
+use libfuzzer_sys::fuzz_target;
+use sap::Parser;
+
+fuzz_target!(|data: &[u8]| {
+    let mut args: Vec<String> = vec!["fuzz".to_string()];
+
+    for &byte in data {
+        args.push(format!("{}", byte));
+        args.push(format!("{:x}", byte));
+        args.push(format!("{:b}", byte));
+        args.push(format!("{}", byte as char));
+        args.push(format!("-{}", byte as char));
+        args.push(format!("--{}", byte as char));
+        args.push(format!("--{}={}", byte as char, byte));
+        args.push(format!("--{}={:x}", byte, byte));
+    }
+
+    if let Ok(mut parser) = Parser::from_arbitrary(args) {
+        while let Ok(Some(_)) = parser.forward() {
+            let _ = parser.value();
+        }
+    }
+});