From 8d268663eff28a97e912b5dcf3dc25508cb6dfce Mon Sep 17 00:00:00 2001
From: Abtin Keshavarzian <abtink@google.com>
Date: Thu, 23 Sep 2021 09:18:29 -0700
Subject: [PATCH] [mac] update `Mac::NameData` to use `Data` (#7026)

This commit updates `Mac::NameData` to use `Data` as its base
class and then use its method in the `NameData` implementation.
---
 src/core/mac/mac_types.cpp    | 41 +++++++++++++++--------------------
 src/core/mac/mac_types.hpp    | 21 +++++++-----------
 tests/unit/test_mac_frame.cpp |  7 ++++++
 3 files changed, 33 insertions(+), 36 deletions(-)

diff --git a/src/core/mac/mac_types.cpp b/src/core/mac/mac_types.cpp
index ef1c0c414..3a3bdc3e0 100644
--- a/src/core/mac/mac_types.cpp
+++ b/src/core/mac/mac_types.cpp
@@ -121,25 +121,18 @@ ExtendedPanId::InfoString ExtendedPanId::ToString(void) const
 
 uint8_t NameData::CopyTo(char *aBuffer, uint8_t aMaxSize) const
 {
-    uint8_t len = GetLength();
+    MutableData<kWithUint8Length> destData;
 
-    memset(aBuffer, 0, aMaxSize);
+    destData.Init(aBuffer, aMaxSize);
+    destData.ClearBytes();
+    IgnoreError(destData.CopyBytesFrom(*this));
 
-    if (len > aMaxSize)
-    {
-        len = aMaxSize;
-    }
-
-    memcpy(aBuffer, GetBuffer(), len);
-
-    return len;
+    return destData.GetLength();
 }
 
 NameData NetworkName::GetAsData(void) const
 {
-    uint8_t len = static_cast<uint8_t>(StringLength(m8, kMaxSize + 1));
-
-    return NameData(m8, len);
+    return NameData(m8, static_cast<uint8_t>(StringLength(m8, kMaxSize + 1)));
 }
 
 Error NetworkName::Set(const char *aNameString)
@@ -165,15 +158,21 @@ exit:
 
 Error NetworkName::Set(const NameData &aNameData)
 {
-    Error   error  = kErrorNone;
-    uint8_t newLen = static_cast<uint8_t>(StringLength(aNameData.GetBuffer(), aNameData.GetLength()));
+    Error    error  = kErrorNone;
+    NameData data   = aNameData;
+    uint8_t  newLen = static_cast<uint8_t>(StringLength(data.GetBuffer(), data.GetLength()));
 
     VerifyOrExit((0 < newLen) && (newLen <= kMaxSize), error = kErrorInvalidArgs);
 
-    // Ensure the new name does not match the current one.
-    VerifyOrExit(memcmp(m8, aNameData.GetBuffer(), newLen) || (m8[newLen] != '\0'), error = kErrorAlready);
+    data.SetLength(newLen);
 
-    memcpy(m8, aNameData.GetBuffer(), newLen);
+    // Ensure the new name does not match the current one.
+    if (data.MatchesBytesIn(m8) && m8[newLen] == '\0')
+    {
+        ExitNow(error = kErrorAlready);
+    }
+
+    data.CopyBytesTo(m8);
     m8[newLen] = '\0';
 
 exit:
@@ -182,11 +181,7 @@ exit:
 
 bool NetworkName::operator==(const NetworkName &aOther) const
 {
-    NameData data      = GetAsData();
-    NameData otherData = aOther.GetAsData();
-
-    return (data.GetLength() == otherData.GetLength()) &&
-           (memcmp(data.GetBuffer(), otherData.GetBuffer(), data.GetLength()) == 0);
+    return GetAsData() == aOther.GetAsData();
 }
 
 #if OPENTHREAD_CONFIG_MULTI_RADIO
diff --git a/src/core/mac/mac_types.hpp b/src/core/mac/mac_types.hpp
index f04dfed17..b1e53b78a 100644
--- a/src/core/mac/mac_types.hpp
+++ b/src/core/mac/mac_types.hpp
@@ -43,6 +43,7 @@
 #include <openthread/thread.h>
 
 #include "common/clearable.hpp"
+#include "common/data.hpp"
 #include "common/equatable.hpp"
 #include "common/string.hpp"
 #include "crypto/storage.hpp"
@@ -583,8 +584,10 @@ public:
  * @note The char array does NOT need to be null terminated.
  *
  */
-class NameData
+class NameData : private Data<kWithUint8Length>
 {
+    friend class NetworkName;
+
 public:
     /**
      * This constructor initializes the NameData object.
@@ -593,11 +596,7 @@ public:
      * @param[in] aLength   The length (number of chars) in the buffer.
      *
      */
-    NameData(const char *aBuffer, uint8_t aLength)
-        : mBuffer(aBuffer)
-        , mLength(aLength)
-    {
-    }
+    NameData(const char *aBuffer, uint8_t aLength) { Init(aBuffer, aLength); }
 
     /**
      * This method returns the pointer to char buffer (not necessarily null terminated).
@@ -605,7 +604,7 @@ public:
      * @returns The pointer to the char buffer.
      *
      */
-    const char *GetBuffer(void) const { return mBuffer; }
+    const char *GetBuffer(void) const { return reinterpret_cast<const char *>(GetBytes()); }
 
     /**
      * This method returns the length (number of chars in buffer).
@@ -613,7 +612,7 @@ public:
      * @returns The name length.
      *
      */
-    uint8_t GetLength(void) const { return mLength; }
+    uint8_t GetLength(void) const { return Data<kWithUint8Length>::GetLength(); }
 
     /**
      * This method copies the name data into a given char buffer with a given size.
@@ -628,17 +627,13 @@ public:
      *
      */
     uint8_t CopyTo(char *aBuffer, uint8_t aMaxSize) const;
-
-private:
-    const char *mBuffer;
-    uint8_t     mLength;
 };
 
 /**
  * This structure represents an IEEE802.15.4 Network Name.
  *
  */
-class NetworkName : public otNetworkName
+class NetworkName : public otNetworkName, public Unequatable<NetworkName>
 {
 public:
     /**
diff --git a/tests/unit/test_mac_frame.cpp b/tests/unit/test_mac_frame.cpp
index 84826f1a0..b5d5796d6 100644
--- a/tests/unit/test_mac_frame.cpp
+++ b/tests/unit/test_mac_frame.cpp
@@ -175,6 +175,7 @@ void TestMacNetworkName(void)
     char             buffer[sizeof(kTooLongName) + 2];
     uint8_t          len;
     Mac::NetworkName networkName;
+    Mac::NetworkName networkName2;
 
     CompareNetworkName(networkName, kEmptyName);
 
@@ -224,6 +225,12 @@ void TestMacNetworkName(void)
     VerifyOrQuit(len == sizeof(kName1) - 1, "NameData::CopyTo() failed");
     VerifyOrQuit(memcmp(buffer, kName1, sizeof(kName1) - 1) == 0, "NameData::CopyTo() failed");
     VerifyOrQuit(buffer[sizeof(kName1)] == 0, "NameData::CopyTo() failed");
+
+    SuccessOrQuit(networkName2.Set(Mac::NameData(kName1, sizeof(kName1))));
+    VerifyOrQuit(networkName == networkName2);
+
+    SuccessOrQuit(networkName2.Set(kName2));
+    VerifyOrQuit(networkName != networkName2);
 }
 
 void TestMacHeader(void)