diff --git a/tdutils/td/utils/Parser.h b/tdutils/td/utils/Parser.h
index 09584ea2e..6ac1b7aee 100644
--- a/tdutils/td/utils/Parser.h
+++ b/tdutils/td/utils/Parser.h
@@ -160,11 +160,11 @@ class Parser {
     return status_;
   }
 
-  bool start_with(Slice prefix) {
-    if (prefix.size() + ptr_ > end_) {
+  bool start_with(Slice prefix) const {
+    if (prefix.size() > static_cast<size_t>(end_ - ptr_)) {
       return false;
     }
-    return std::memcmp(prefix.begin(), ptr_, prefix.size()) == 0;
+    return prefix == Slice(ptr_, prefix.size());
   }
 
   bool skip_start_with(Slice prefix) {
diff --git a/tdutils/td/utils/UInt.h b/tdutils/td/utils/UInt.h
index bf81a2e1c..60160df31 100644
--- a/tdutils/td/utils/UInt.h
+++ b/tdutils/td/utils/UInt.h
@@ -48,7 +48,7 @@ struct UInt {
 
 template <size_t size>
 bool operator==(const UInt<size> &a, const UInt<size> &b) {
-  return std::memcmp(a.raw, b.raw, sizeof(a.raw)) == 0;
+  return a.as_slice() == b.as_slice();
 }
 
 template <size_t size>
@@ -84,7 +84,7 @@ MutableSlice as_slice(UInt<size> &value) {
 
 template <size_t size>
 bool operator<(const UInt<size> &a, const UInt<size> &b) {
-  return std::memcmp(a.raw, b.raw, sizeof(a.raw)) < 0;
+  return a.as_slice() < b.as_slice();
 }
 
 using UInt128 = UInt<128>;
diff --git a/tdutils/td/utils/find_boundary.cpp b/tdutils/td/utils/find_boundary.cpp
index 539179343..9c47f3911 100644
--- a/tdutils/td/utils/find_boundary.cpp
+++ b/tdutils/td/utils/find_boundary.cpp
@@ -24,7 +24,7 @@ bool find_boundary(ChainBufferReader range, Slice boundary, size_t &already_read
       auto save_range = range.clone();
       char x[MAX_BOUNDARY_LENGTH + 4];
       range.advance(boundary.size(), {x, sizeof(x)});
-      if (std::memcmp(x, boundary.data(), boundary.size()) == 0) {
+      if (Slice(x, boundary.size()) == boundary) {
         return true;
       }