OSS-Fuzz: Add new fuzzer upstream

Signed-off-by: Arthur Chan <[email protected]>

Author: arthurscchan

fuzz/Cargo.toml

@@ -23,5 +23,11 @@ path = "fuzz_targets/streaming.rs"
 test = false
 doc = false
 
+[[bin]]
+name = "process"
+path = "fuzz_targets/process.rs"
+test = false
+doc = false
+
 # Work around https://github.com/rust-lang/cargo/issues/8338
 [workspace]

fuzz/fuzz_targets/process.rs

@@ -0,0 +1,74 @@
+// The fuzzing harness fuzz test some of the the
+// unicode string normalization processing
+
+#![no_main]
+
+#[macro_use]
+extern crate libfuzzer_sys;
+extern crate unicode_normalization;
+
+use unicode_normalization::{
+    char::{compose, canonical_combining_class, is_combining_mark, decompose_canonical, decompose_compatible},
+    UnicodeNormalization,
+};
+
+fuzz_target!(|data: &[u8]| {
+    let mut data = data;
+    let c = if let Some((char_value, remaining_data)) = data.split_first() {
+        match std::char::from_u32(*char_value as u32) {
+            Some(ch) => {
+                data = remaining_data;
+                ch
+            }
+            None => return,
+        }
+    } else {
+        return;
+    };
+
+    // Generate second character for fuzzing if data is enough
+    let c2 = if let Some((char_value, remaining_data)) = data.split_first() {
+        data = remaining_data;
+        std::char::from_u32(*char_value as u32)
+    } else {
+        None
+    };
+    let string_data: String = data.iter().filter_map(|&b| std::char::from_u32(b as u32)).collect();
+
+    // Randomly choose a function target
+    match data.first().map(|&b| b % 10) {
+        Some(0) => {
+            if let Some(c2) = c2 {
+                let _ = compose(c, c2);
+            }
+        }
+        Some(1) => {
+            let _ = canonical_combining_class(c);
+        }
+        Some(2) => {
+            let _ = is_combining_mark(c);
+        }
+        Some(3) => {
+            let _ = string_data.nfc().collect::<String>();
+        }
+        Some(4) => {
+            let _ = string_data.nfkd().collect::<String>();
+        }
+        Some(5) => {
+            let _ = string_data.nfd().collect::<String>();
+        }
+        Some(6) => {
+            let _ = string_data.nfkc().collect::<String>();
+        }
+        Some(7) => {
+            let _ = string_data.stream_safe().collect::<String>();
+        }
+        Some(8) => {
+            decompose_canonical(c, |_| {});
+        }
+        Some(9) => {
+            decompose_compatible(c, |_| {});
+        }
+        _ => {}
+    }
+});