From b5f24e53792127b221c539ba22db6375b61bd131 Mon Sep 17 00:00:00 2001
From: Twice <twice.mliu@gmail.com>
Date: Sun, 20 Aug 2023 10:21:46 +0800
Subject: [PATCH] Add returned next pointer for EncodeFixed (#1685)

---
 src/common/encoding.cc        |  2 +-
 src/common/encoding.h         | 19 +++++++++++++------
 src/storage/redis_metadata.cc | 22 +++++++---------------
 3 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/src/common/encoding.cc b/src/common/encoding.cc
index c2f738c97ed..e17fbd347c9 100644
--- a/src/common/encoding.cc
+++ b/src/common/encoding.cc
@@ -58,7 +58,7 @@ inline double DecodeDoubleFromUInt64(uint64_t value) {
   return result;
 }
 
-void EncodeDouble(char *buf, double value) { EncodeFixed64(buf, EncodeDoubleToUInt64(value)); }
+char *EncodeDouble(char *buf, double value) { return EncodeFixed64(buf, EncodeDoubleToUInt64(value)); }
 
 void PutDouble(std::string *dst, double value) { PutFixed64(dst, EncodeDoubleToUInt64(value)); }
 
diff --git a/src/common/encoding.h b/src/common/encoding.h
index 1fa4b020ffa..d497793068a 100644
--- a/src/common/encoding.h
+++ b/src/common/encoding.h
@@ -44,17 +44,24 @@ constexpr inline uint32_t BitSwap(uint32_t x) { return __builtin_bswap32(x); }
 constexpr inline uint64_t BitSwap(uint64_t x) { return __builtin_bswap64(x); }
 
 template <typename T>
-constexpr void EncodeFixed(char *buf, T value) {
+constexpr char *EncodeFixed(char *buf, T value) {
   if constexpr (IsLittleEndian()) {
     value = BitSwap(value);
   }
   __builtin_memcpy(buf, &value, sizeof(value));
+  return buf + sizeof(value);
 }
 
-inline void EncodeFixed8(char *buf, uint8_t value) { EncodeFixed(buf, value); }
-inline void EncodeFixed16(char *buf, uint16_t value) { EncodeFixed(buf, value); }
-inline void EncodeFixed32(char *buf, uint32_t value) { EncodeFixed(buf, value); }
-inline void EncodeFixed64(char *buf, uint64_t value) { EncodeFixed(buf, value); }
+inline char *EncodeFixed8(char *buf, uint8_t value) { return EncodeFixed(buf, value); }
+inline char *EncodeFixed16(char *buf, uint16_t value) { return EncodeFixed(buf, value); }
+inline char *EncodeFixed32(char *buf, uint32_t value) { return EncodeFixed(buf, value); }
+inline char *EncodeFixed64(char *buf, uint64_t value) { return EncodeFixed(buf, value); }
+
+inline char *EncodeBuffer(char *buf, rocksdb::Slice value) {
+  __builtin_memcpy(buf, value.data(), value.size());
+
+  return buf + value.size();
+}
 
 template <typename T>
 void PutFixed(std::string *dst, T value) {
@@ -95,7 +102,7 @@ inline bool GetFixed16(rocksdb::Slice *input, uint16_t *value) { return GetFixed
 inline bool GetFixed32(rocksdb::Slice *input, uint32_t *value) { return GetFixed(input, value); }
 inline bool GetFixed64(rocksdb::Slice *input, uint64_t *value) { return GetFixed(input, value); }
 
-void EncodeDouble(char *buf, double value);
+char *EncodeDouble(char *buf, double value);
 void PutDouble(std::string *dst, double value);
 double DecodeDouble(const char *ptr);
 bool GetDouble(rocksdb::Slice *input, double *value);
diff --git a/src/storage/redis_metadata.cc b/src/storage/redis_metadata.cc
index 4c6b6c5c19f..4157866f53d 100644
--- a/src/storage/redis_metadata.cc
+++ b/src/storage/redis_metadata.cc
@@ -77,29 +77,21 @@ uint64_t InternalKey::GetVersion() const { return version_; }
 
 std::string InternalKey::Encode() const {
   std::string out;
-  size_t pos = 0;
   size_t total = 1 + namespace_.size() + 4 + key_.size() + 8 + sub_key_.size();
   if (slot_id_encoded_) {
     total += 2;
   }
   out.resize(total);
   auto buf = out.data();
-  EncodeFixed8(buf + pos, static_cast<uint8_t>(namespace_.size()));
-  pos += 1;
-  memcpy(buf + pos, namespace_.data(), namespace_.size());
-  pos += namespace_.size();
+  buf = EncodeFixed8(buf, static_cast<uint8_t>(namespace_.size()));
+  buf = EncodeBuffer(buf, namespace_);
   if (slot_id_encoded_) {
-    EncodeFixed16(buf + pos, slotid_);
-    pos += 2;
+    buf = EncodeFixed16(buf, slotid_);
   }
-  EncodeFixed32(buf + pos, static_cast<uint32_t>(key_.size()));
-  pos += 4;
-  memcpy(buf + pos, key_.data(), key_.size());
-  pos += key_.size();
-  EncodeFixed64(buf + pos, version_);
-  pos += 8;
-  memcpy(buf + pos, sub_key_.data(), sub_key_.size());
-  // pos += sub_key_.size();
+  buf = EncodeFixed32(buf, static_cast<uint32_t>(key_.size()));
+  buf = EncodeBuffer(buf, key_);
+  buf = EncodeFixed64(buf, version_);
+  EncodeBuffer(buf, sub_key_);
   return out;
 }