From f47222615abaef97564299b7e4a1fdc61557b359 Mon Sep 17 00:00:00 2001
From: Chandan-M-N <chandan7c77@gmail.com>
Date: Sat, 23 Nov 2024 20:49:45 -0500
Subject: [PATCH] Updated Fuzz, added an execetion in string function

---
 fuzz/fuzz_targets/fuzz_target_1.rs | 26 +++++++--------
 src/stringfn.rs                    | 52 ++++++++++++++++++------------
 2 files changed, 44 insertions(+), 34 deletions(-)

diff --git a/fuzz/fuzz_targets/fuzz_target_1.rs b/fuzz/fuzz_targets/fuzz_target_1.rs
index ad112e9..72e9ebb 100644
--- a/fuzz/fuzz_targets/fuzz_target_1.rs
+++ b/fuzz/fuzz_targets/fuzz_target_1.rs
@@ -52,9 +52,7 @@ fn fuzz_homomorphic_operations(
     ];
     for (i, result) in add_results.iter().enumerate() {
         let decrypted_add = decryptor.decrypt(result);
-        println!("{:?},{:?}",decrypted_add,data1);
         assert_eq!(decrypted_add.len(), data1.len());
-        println!("Addition result {}: {:?}", i, decrypted_add);
     }
 
     // Test homomorphic_subtract with all combinations
@@ -66,7 +64,6 @@ fn fuzz_homomorphic_operations(
     for (i, result) in sub_results.iter().enumerate() {
         let decrypted_sub = decryptor.decrypt(result);
         assert_eq!(decrypted_sub.len(), data1.len());
-        println!("Subtraction result {}: {:?}", i, decrypted_sub);
     }
 
     // Test homomorphic_multiply with all combinations
@@ -78,19 +75,25 @@ fn fuzz_homomorphic_operations(
     for (i, result) in mul_results.iter().enumerate() {
         let decrypted_mul = decryptor.decrypt(result);
         assert_eq!(decrypted_mul.len(), data1.len());
-        println!("Multiplication result {}: {:?}", i, decrypted_mul);
     }
 
     // Test homomorphic_divide with all combinations
     let div_results = [
-        encryptor.homomorphic_divide(&enc_collection1, &enc_value),
-        encryptor.homomorphic_divide(&enc_value, &enc_collection1),
-        encryptor.homomorphic_divide(&enc_collection1, &enc_collection1),
+    encryptor.homomorphic_divide(&enc_collection1, &enc_value),
+    encryptor.homomorphic_divide(&enc_value, &enc_collection1),
+    encryptor.homomorphic_divide(&enc_collection1, &enc_collection1),
     ];
+
     for (i, result) in div_results.iter().enumerate() {
         let decrypted_div = decryptor.decrypt(result);
-        println!("{:?},{:?}",decrypted_div,data1);
-        println!("Division result {}: {:?}", i, decrypted_div);
+
+        // Skip assertion if the decrypted result is empty (indicating a division by zero)
+        if decrypted_div.is_empty() {
+            println!("Skipping assertion for index {} due to division by zero.", i);
+            continue;
+        }
+
+        assert_eq!(decrypted_div.len(), data1.len());
     }
 }
 
@@ -141,10 +144,7 @@ fn fuzz_advanced_operations(
     let decrypted_exp = decryptor.decrypt(&exp_result);
     assert_eq!(decrypted_exp.len(), data.len());
 
-    let div_result = encryptor.homomorphic_divide(&encrypted_data, &encrypted_value);
-    let decrypted_div = decryptor.decrypt(&div_result);
-    println!("{:?}", decrypted_div);
-    println!("{:?}", data);
+
 }
 
 fuzz_target!(|data: &[u8]| {
diff --git a/src/stringfn.rs b/src/stringfn.rs
index 6f66759..a6af9a3 100644
--- a/src/stringfn.rs
+++ b/src/stringfn.rs
@@ -30,26 +30,36 @@ impl CKKSEncryptor {
     /// - `encrypted_poly`: The encrypted string as a polynomial.
     /// - `range`: A range representing the indices to extract (e.g., `0..3`, `3..`, `..5`).
     pub fn extract_encrypted_substring<R>(&self, encrypted_poly: &Polynomial, range: R) -> Polynomial
-    where
-        R: RangeBounds<usize>,
-    {
-        // Convert RangeBounds into a concrete Range<usize>
-        let start = match range.start_bound() {
-            std::ops::Bound::Included(&s) => s,
-            std::ops::Bound::Excluded(&s) => s + 1,
-            std::ops::Bound::Unbounded => 0,
-        };
-
-        let end = match range.end_bound() {
-            std::ops::Bound::Included(&e) => e + 1,
-            std::ops::Bound::Excluded(&e) => e,
-            std::ops::Bound::Unbounded => encrypted_poly.coeffs.len(),
-        };
-
-        // Apply the range to get the substring coefficients
-        let substring_coeffs = encrypted_poly.coeffs[start..end].to_vec();
-
-        // Return a new polynomial with the substring coefficients
-        Polynomial::new(substring_coeffs)
+where
+    R: RangeBounds<usize>,
+{
+    // Convert RangeBounds into a concrete Range<usize>
+    let start = match range.start_bound() {
+        std::ops::Bound::Included(&s) => s,
+        std::ops::Bound::Excluded(&s) => s + 1,
+        std::ops::Bound::Unbounded => 0,
+    };
+
+    let end = match range.end_bound() {
+        std::ops::Bound::Included(&e) => e + 1,
+        std::ops::Bound::Excluded(&e) => e,
+        std::ops::Bound::Unbounded => encrypted_poly.coeffs.len(),
+    };
+
+    // Ensure start and end are within bounds
+    let start = start.clamp(0, encrypted_poly.coeffs.len());
+    let end = end.clamp(0, encrypted_poly.coeffs.len());
+
+    if start >= end {
+        // If the range is invalid (start >= end), return an empty polynomial
+        return Polynomial::new(vec![]);
     }
+
+    // Apply the range to get the substring coefficients
+    let substring_coeffs = encrypted_poly.coeffs[start..end].to_vec();
+
+    // Return a new polynomial with the substring coefficients
+    Polynomial::new(substring_coeffs)
+}
+
 }