From 8bf83bfcd08b5410fd25851eee490b1ea5dff9af Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20=27birdy=27=20Danjou?= <clement@danjou.io>
Date: Mon, 26 Jun 2023 19:38:00 +0200
Subject: [PATCH] feat() add isInitialized function

---
 codegen/codegen.py        | 11 +++++++++++
 examples/BlindAuction.sol |  4 ++--
 lib/TFHE.sol              | 12 ++++++++++++
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/codegen/codegen.py b/codegen/codegen.py
index 88a1609..5ad0132 100644
--- a/codegen/codegen.py
+++ b/codegen/codegen.py
@@ -536,6 +536,17 @@ import "./Common.sol";
 import "./Impl.sol";
 
 library TFHE {""")
+        
+to_print_is_initialized =  """
+    function isInitialized(euint{i} v) internal pure returns (bool) {{
+        return euint{i}.unwrap(v) != 0;
+    }}
+"""
+
+f.write(to_print_is_initialized.format(i=8))
+f.write(to_print_is_initialized.format(i=16))
+f.write(to_print_is_initialized.format(i=32))
+
 
 to_print_no_cast =  """
     function {f}(euint{i} a, euint{j} b) internal view returns (euint{k}) {{
diff --git a/examples/BlindAuction.sol b/examples/BlindAuction.sol
index 7352c94..10665e9 100644
--- a/examples/BlindAuction.sol
+++ b/examples/BlindAuction.sol
@@ -63,7 +63,7 @@ contract BlindAuction is EIP712WithModifier {
     function bid(bytes calldata encryptedValue) public onlyBeforeEnd {
         euint32 value = TFHE.asEuint32(encryptedValue);
         euint32 existingBid = bids[msg.sender];
-        if (euint32.unwrap(existingBid) != 0) {
+        if (TFHE.isInitialized(existingBid)) {
             euint32 isHigher = TFHE.lt(existingBid, value);
             // Update bid with value
             bids[msg.sender] = TFHE.cmux(isHigher, value, existingBid);
@@ -78,7 +78,7 @@ contract BlindAuction is EIP712WithModifier {
             tokenContract.transferFrom(msg.sender, address(this), value);
         }
         euint32 currentBid = bids[msg.sender];
-        if (euint32.unwrap(highestBid) == 0) {
+        if (!TFHE.isInitialized(highestBid)) {
             highestBid = currentBid;
         } else {
             highestBid = TFHE.cmux(
diff --git a/lib/TFHE.sol b/lib/TFHE.sol
index c550c91..9d3798d 100644
--- a/lib/TFHE.sol
+++ b/lib/TFHE.sol
@@ -6,6 +6,18 @@ import "./Common.sol";
 import "./Impl.sol";
 
 library TFHE {
+    function isInitialized(euint8 v) internal pure returns (bool) {
+        return euint8.unwrap(v) != 0;
+    }
+
+    function isInitialized(euint16 v) internal pure returns (bool) {
+        return euint16.unwrap(v) != 0;
+    }
+
+    function isInitialized(euint32 v) internal pure returns (bool) {
+        return euint32.unwrap(v) != 0;
+    }
+
     function add(euint8 a, euint8 b) internal view returns (euint8) {
         return euint8.wrap(Impl.add(euint8.unwrap(a), euint8.unwrap(b)));
     }