feat: string cmd getbit

src/base_cmd.h

@@ -34,6 +34,7 @@ const std::string kCmdNameStrlen = "strlen";
 const std::string kCmdNameSetex = "setex";
 const std::string kCmdNamePsetex = "psetex";
 const std::string kCmdNameSetnx = "setnx";
+const std::string kCmdNameGetBit = "getbit";
 
 // multi
 const std::string kCmdNameMulti = "multi";

src/cmd_kv.cc

@@ -456,4 +456,47 @@ void SetnxCmd::DoCmd(PClient* client) {
   }
 }
 
+GetBitCmd::GetBitCmd(const std::string& name, int16_t arity)
+    : BaseCmd(name, arity, CmdFlagsWrite, AclCategoryWrite | AclCategoryString) {}
+
+bool GetBitCmd::DoInitial(PClient* client) {
+  client->SetKey(client->argv_[1]);
+  return true;
+}
+
+void GetBitCmd::DoCmd(PClient* client) {
+  PObject* value = nullptr;
+  PError err = PSTORE.GetValueByType(client->Key(), value, PType_string);
+  if (err != PError_ok) {
+    client->SetRes(CmdRes::kErrOther);
+    return;
+  }
+
+  long offset = 0;
+  if (!Strtol(client->argv_[2].c_str(), client->argv_[2].size(), &offset)) {
+    client->SetRes(CmdRes::kInvalidInt);
+    return;
+  }
+
+  auto str = GetDecodedString(value);
+  const uint8_t* buf = (const uint8_t*)str->c_str();
+  size_t size = 8 * str->size();
+
+  if (offset < 0 || offset >= static_cast<long>(size)) {
+    client->AppendInteger(0);
+    return;
+  }
+
+  size_t bytesOffset = offset / 8;
+  size_t bitsOffset = offset % 8;
+  uint8_t byte = buf[bytesOffset];
+  if (byte & (0x1 << bitsOffset)) {
+    client->AppendInteger(1);
+  } else {
+    client->AppendInteger(0);
+  }
+
+  return;
+}
+
 }  // namespace pikiwidb

src/cmd_kv.h

@@ -160,4 +160,15 @@ class IncrbyCmd : public BaseCmd {
   void DoCmd(PClient *client) override;
 };
 
+class GetBitCmd : public BaseCmd {
+ public:
+  GetBitCmd(const std::string &name, int16_t arity);
+
+ protected:
+  bool DoInitial(PClient *client) override;
+
+ private:
+  void DoCmd(PClient *client) override;
+};
+
 }  // namespace pikiwidb

src/cmd_table_manager.cc

@@ -62,6 +62,8 @@ void CmdTableManager::InitCmdTable() {
   cmds_->insert(std::make_pair(kCmdNamePsetex, std::move(psetexPtr)));
   std::unique_ptr<BaseCmd> setnxPtr = std::make_unique<SetnxCmd>(kCmdNameSetnx, 3);
   cmds_->insert(std::make_pair(kCmdNameSetnx, std::move(setnxPtr)));
+  std::unique_ptr<BaseCmd> getbitPtr = std::make_unique<GetBitCmd>(kCmdNameGetBit, 3);
+  cmds_->insert(std::make_pair(kCmdNameGetBit, std::move(getbitPtr)));
 }
 
 std::pair<BaseCmd*, CmdRes::CmdRet> CmdTableManager::GetCommand(const std::string& cmdName, PClient* client) {