Object statistics lru

core/eval.go

@@ -38,6 +38,37 @@
 	return b
 }
 
+
+func evalINCR(args []string)[]byte{
+	if len(args)!=1{
+		return Encode(errors.New("ERR wrong number of arguments for 'incr' command"),false)
+	}
+
+	var key string=args[0] //first wala argument lenge hum isme 
+	obj:=Get(key)
+	//basically we will get an object and if that obejct doesn;t exits then we will create a new object
+	if obj==nil{
+		obj=NewObj("0",-1,OBJ_TYPE_STRING,OBJ_ENCODING_INT)
+		Put(key,obj)
+	}
+
+	if err:=assertType(obj.TypeEncoding,OBJ_TYPE_STRING);err!=nil{
+		return Encode(err,false)
+	}
+
+	if err:=assertEncoding(obj.TypeEncoding,OBJ_ENCODING_INT);err!=nil{
+		return Encode(err,false)
+	}
+	//which means value is indeed an integer
+	i,_:=strconv.ParseInt(obj.Value,(string),10,64)
+	i++
+	obj.Value=strconv.FormatInt(i,10)
+
+	return Encode(i,false)
+}
+
+
+
 func evalSET(args []string) []byte{
 	//similarly for evalSET
 	if len(args) <= 1{
@@ -49,6 +80,7 @@
 	var exDurationMs int64 = -1//as we know ki default value of expiration is -1
 
 	key, value = args[0], args[1]
+	otype,oEnc:=deduceTypeEncoding(value)
 
 	for i := 2; i < len(args); i++{
 		//as we are only implementing expiration as of now par SET functions implements a lot of other options too
@@ -75,7 +107,7 @@
 
 	//after this we have key,value set and it is ptional for expiration
 	//so we will create a new Object
-	Put(key, NewObj(value, exDurationMs))
+	Put(key, NewObj(value, exDurationMs, otype, oEnc))
 	// c.Write([]byte("+OK\r\n"))
 	// return nil
 	return RESP_OK
@@ -226,6 +258,8 @@
 			buf.Write(evalEXPIRE(cmd.Args))
 		case "BGREWRITEAOF":
 			buf.Write(evalBGREWRITEAOF(cmd.Args))
+		case "INCR":
+			buf.Write(evalPING(cmd.Args))
 		default:
 			buf.Write(evalPING(cmd.Args))
 		}

core/object.go

@@ -0,0 +1,26 @@
+package core 
+
+
+//TODO: Change ExpiresAt it to LRU Bits as handled by Redis
+type Obj struct{
+	TypeEncoding uint8
+	Value        interface{}
+	ExpiresAt    int64
+}
+/*
+C and c++ give us ways to apply bit fields on set, means in each set i can assign a fix number of bits
+so i am deifning type encoding 
+
+
+if i am storing type encoding in c/c++, i could do it via bit field s since i don't have assembler here so 
+we are doing like this way, or or krke krrhe hai
+*/
+
+var OBJ_TYPE_STRING uint8=0<<4 //because first 4 bits i want to set
+
+var OBJ_ENCODING_RAW uint8=0
+var OBJ_ENCODING_INT uint8=1
+var OBJ_ENCODING_ENDSTR uint8=8
+
+
+

core/store.go

@@ -9,7 +9,7 @@
 var store map[string]*Obj
 //the best datastrcuture to hold key value is hash table so we are using it
 
 type Obj struct{
 	Value interface{} //which means we acn put literally anything,anyvalue and which would work fine
 	ExpiresAt int64 //is time ke baad expire hojayega wo
 }
@@ -18,7 +18,9 @@
 	store=make(map[string]*Obj)
 }
 
-func NewObj(value interface{},DurationMs int64) *Obj{
+//eralier we used to take (value interface{},DurationMs int64)
+//but now we are also stroing type encoding so, 1 for object type and 1 for encdojgn
+func NewObj(value interface{},DurationMs int64,oType uint8,oEnc uint8) *Obj{
 	//creating a new object, setting things up and returning another object
 	//since we want to store abolution expires instead of doing it multiple time that's why we have created this fucntion
 	var expiresAt int64=-1
@@ -28,6 +30,7 @@
 
 	return &Obj{
 		Value: value,
+		TypeEncoding: oType|oEnc,
 		ExpiresAt: expiresAt,
 	}
 }

core/type_string.go

@@ -0,0 +1,18 @@
+package core
+
+import "strconv"
+
+
+//Similar to
+//tryObjectEncoding Function in redis
+func deduceTypeEncoding(v string)(uint8,uint8){
+	oType:=OBJ_TYPE_STRING
+	if _,rr:=strconv.ParseInt(v,10,64);err==nil{
+		return oType,OBJ_ENCODING_INT //we are converting ans stroing int as a string inside my redis object
+	}
+	if len(v)<=44{
+		return oType,OBJ_ENCODING_EMBSTR //Object encoding is embedded string
+	}
+	return oType,OBJ_ENCODING_RAW
+}
+

core/typeencoding.go

@@ -0,0 +1,63 @@
+package core
+import "errors"
+
+/*
+From a particular type encoding object if you want to get type of it
+type is definately the first 4 bits 
+
+so inorder to extract that i am right shifting by 4 and then left shift by 4
+*/
+func getType(te uint8) uint8{
+	return (te>>4)<<4
+}
+
+func getEncoding(te uint8) uint8{
+	return te & 0b00001111
+}
+
+func assertType(te uint8,t uint8)error{
+	if getType(te)!=t{
+		return errors.New("the operation is not permitted on this type")
+	}
+	return nil
+}
+
+
+func assertEncoding(te uint8,e uint8)error{
+	if getEncoding(te)!=e{
+		return errors.New("the operations is not permitted on this encoding")
+	}
+	return nil
+}
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