diff --git a/contrib/jsonb_plperl/jsonb_plperl.c b/contrib/jsonb_plperl/jsonb_plperl.c
index 52b2d35..80be238 100644
--- a/contrib/jsonb_plperl/jsonb_plperl.c
+++ b/contrib/jsonb_plperl/jsonb_plperl.c
@@ -18,132 +18,134 @@
 
 PG_MODULE_MAGIC;
 
-static SV  *SV_FromJsonb(JsonbContainer *jsonb);
-
-static JsonbValue *HV_ToJsonbValue(HV *obj, JsonbParseState *jsonb_state);
-
-static JsonbValue *SV_ToJsonbValue(SV *obj, JsonbParseState *jsonb_state);
+static SV  *Jsonb_ToSV(JsonbContainer *jsonb);
+static JsonbValue *SV_ToJsonbValue(SV *obj, JsonbParseState **ps, bool is_elem);
 
 /*
- * SV_FromJsonbValue
+ * JsonbValue_ToSV
  *
  * Transform JsonbValue into SV
  */
 static SV  *
-SV_FromJsonbValue(JsonbValue *jsonbValue)
+JsonbValue_ToSV(JsonbValue *jbv)
 {
 	dTHX;
-	SV		   *result;
-	char	   *str;
 
-	switch (jsonbValue->type)
+	switch (jbv->type)
 	{
 		case jbvBinary:
-			result = (SV *) newRV((SV *) SV_FromJsonb(jsonbValue->val.binary.data));
-			break;
+			return newRV(Jsonb_ToSV(jbv->val.binary.data));
+
 		case jbvNumeric:
+			{
+				/*
+				 * Transform incoming value into string and generate SV from
+				 * string
+				 */
+				char	   *str = DatumGetCString(
+					DirectFunctionCall1(numeric_out,
+										NumericGetDatum(jbv->val.numeric)));
+				SV		   *result = newSVnv(SvNV(cstr2sv(str)));
+
+				pfree(str);
+
+				return result;
+			}
 
-			/*
-			 * Transform incoming value into string and generate SV from
-			 * string
-			 */
-			str = DatumGetCString(DirectFunctionCall1(numeric_out, NumericGetDatum(jsonbValue->val.numeric)));
-			result = newSVnv(SvNV(cstr2sv(pstrdup(str))));
-			break;
 		case jbvString:
-			result = cstr2sv(pnstrdup(jsonbValue->val.string.val, jsonbValue->val.string.len));
-			break;
+			{
+				char	   *str = pnstrdup(jbv->val.string.val,
+										   jbv->val.string.len);
+				SV		   *result = cstr2sv(str);
+
+				pfree(str);
+
+				return result;
+			}
+
 		case jbvBool:
-			result = newSVnv(SvNV(jsonbValue->val.boolean ? &PL_sv_yes : &PL_sv_no));
-			break;
-		case jbvArray:
-			result = SV_FromJsonbValue(jsonbValue->val.array.elems);
-			break;
-		case jbvObject:
-			result = SV_FromJsonbValue(&(jsonbValue->val.object.pairs->value));
-			break;
+			return newSVnv(SvNV(jbv->val.boolean ? &PL_sv_yes : &PL_sv_no));
+
 		case jbvNull:
-			result = newSV(0);
-			break;
+			return newSV(0);
+
 		default:
-			pg_unreachable();
-			break;
+			elog(ERROR, "unexpected jsonb value type: %d", jbv->type);
+			return NULL;
 	}
-	return result;
 }
 
 /*
- * SV_FromJsonb
+ * Jsonb_ToSV
  *
  * Transform JsonbContainer into SV
  */
-static SV  *
-SV_FromJsonb(JsonbContainer *jsonb)
+static SV *
+Jsonb_ToSV(JsonbContainer *jsonb)
 {
 	dTHX;
-	SV		   *result;
-	SV		   *value;
-	JsonbIterator *it;
 	JsonbValue	v;
+	JsonbIterator *it;
+	JsonbIteratorToken r;
 
 	it = JsonbIteratorInit(jsonb);
+	r = JsonbIteratorNext(&it, &v, true);
 
-	switch (JsonbIteratorNext(&it, &v, true))
+	switch (r)
 	{
 		case WJB_BEGIN_ARRAY:
+			if (v.val.array.rawScalar)
+			{
+				JsonbValue tmp;
+
+				if ((r = JsonbIteratorNext(&it, &v, true)) != WJB_ELEM ||
+					(r = JsonbIteratorNext(&it, &tmp, true)) != WJB_END_ARRAY ||
+					(r = JsonbIteratorNext(&it, &tmp, true)) != WJB_DONE)
+					elog(ERROR, "unexpected jsonb token: %d", r);
+
+				return newRV(JsonbValue_ToSV(&v));
+			}
+			else
 			{
-				AV		   *av;
-				bool		raw_scalar;
-
-				/* array in v */
-				av = newAV();
-				raw_scalar = (v.val.array.rawScalar);
-				value = newSV(0);
-				while (JsonbIteratorNext(&it, &v, true) == WJB_ELEM)
+				AV		   *av = newAV();
+
+				while ((r = JsonbIteratorNext(&it, &v, true)) != WJB_DONE)
 				{
-					value = SV_FromJsonbValue(&v);
-					av_push(av, value);
+					if (r == WJB_ELEM)
+						av_push(av, JsonbValue_ToSV(&v));
 				}
-				if (raw_scalar)
-					result = newRV(value);
-				else
-					result = (SV *) av;
-				break;
+
+				return (SV *) av;
 			}
+
 		case WJB_BEGIN_OBJECT:
 			{
-				HV		   *object;
-				const char *key;
-				int			keyLength;
+				HV		   *hv = newHV();
 
-				/* hash in v */
-				object = newHV();
-				while (JsonbIteratorNext(&it, &v, true) == WJB_KEY)
+				while ((r = JsonbIteratorNext(&it, &v, true)) != WJB_DONE)
 				{
-					/* json key in v */
-					keyLength = v.val.string.len;
-					key = pnstrdup(v.val.string.val, keyLength);
-					JsonbIteratorNext(&it, &v, true);
-					value = SV_FromJsonbValue(&v);
-					(void) hv_store(object, key, keyLength, value, 0);
+					if (r == WJB_KEY)
+					{
+						/* json key in v, json value in val */
+						JsonbValue	val;
+
+						if (JsonbIteratorNext(&it, &val, true) == WJB_VALUE)
+						{
+							SV		   *value = JsonbValue_ToSV(&val);
+
+							(void) hv_store(hv, v.val.string.val,
+											v.val.string.len, value, 0);
+						}
+					}
 				}
-				result = (SV *) object;
-				break;
+
+				return (SV *) hv;
 			}
-		case WJB_ELEM:
-		case WJB_VALUE:
-		case WJB_KEY:
-			/* simple objects */
-			result = SV_FromJsonbValue(&v);
-			break;
-		case WJB_DONE:
-		case WJB_END_OBJECT:
-		case WJB_END_ARRAY:
+
 		default:
-			pg_unreachable();
-			break;
+			elog(ERROR, "unexpected jsonb token: %d", r);
+			return NULL;
 	}
-	return result;
 }
 
 /*
@@ -157,9 +159,7 @@ jsonb_to_plperl(PG_FUNCTION_ARGS)
 {
 	dTHX;
 	Jsonb	   *in = PG_GETARG_JSONB_P(0);
-	SV		   *sv;
-
-	sv = SV_FromJsonb(&in->root);
+	SV		   *sv = Jsonb_ToSV(&in->root);
 
 	return PointerGetDatum(newRV(sv));
 }
@@ -171,34 +171,51 @@ jsonb_to_plperl(PG_FUNCTION_ARGS)
  * jsonb_state defines conversion state
  */
 static JsonbValue *
-AV_ToJsonbValue(AV *in, JsonbParseState *jsonb_state)
+AV_ToJsonbValue(AV *in, JsonbParseState **jsonb_state)
 {
 	dTHX;
-
-	JsonbValue *jbvElem;
-	JsonbValue *out = NULL;
-	ssize_t		pcount;
+	ssize_t		pcount = av_len(in) + 1;
 	ssize_t		i;
 
-	pcount = av_len(in) + 1;
-	pushJsonbValue(&jsonb_state, WJB_BEGIN_ARRAY, NULL);
+	pushJsonbValue(jsonb_state, WJB_BEGIN_ARRAY, NULL);
 
 	for (i = 0; i < pcount; i++)
 	{
-		SV		  **value;
+		SV		  **value = av_fetch(in, i, false);
+
+		if (value)
+			(void) SV_ToJsonbValue(*value, jsonb_state, true);
+	}
+
+	return pushJsonbValue(jsonb_state, WJB_END_ARRAY, NULL);
+}
+
+/*
+ * HV_ToJsonbValue
+ *
+ * Transform HV into Jsonb
+ */
+static JsonbValue *
+HV_ToJsonbValue(HV *obj, JsonbParseState **jsonb_state)
+{
+	dTHX;
+	JsonbValue	key;
+	SV		   *val;
+
+	key.type = jbvString;
+
+	pushJsonbValue(jsonb_state, WJB_BEGIN_OBJECT, NULL);
 
-		value = av_fetch(in, i, false);
-		jbvElem = SV_ToJsonbValue(*value, jsonb_state);
+	(void) hv_iterinit(obj);
 
-		/*
-		 * If "value" was a complex structure, it was already pushed to jsonb
-		 * and there is no need to push it again
-		 */
-		if (IsAJsonbScalar(jbvElem))
-			pushJsonbValue(&jsonb_state, WJB_ELEM, jbvElem);
+	while ((val = hv_iternextsv(obj, &key.val.string.val, &key.val.string.len)))
+	{
+		key.val.string.val = pnstrdup(key.val.string.val,key.val.string.len);
+		pushJsonbValue(jsonb_state, WJB_KEY, &key);
+		(void) SV_ToJsonbValue(val, jsonb_state, false);
 	}
-	out = pushJsonbValue(&jsonb_state, WJB_END_ARRAY, NULL);
-	return out;
+
+	return pushJsonbValue(jsonb_state, WJB_END_OBJECT, NULL);
 }
 
 /*
@@ -207,129 +224,92 @@ AV_ToJsonbValue(AV *in, JsonbParseState *jsonb_state)
  * Transform SV into Jsonb
  */
 static JsonbValue *
-SV_ToJsonbValue(SV *in, JsonbParseState *jsonb_state)
+SV_ToJsonbValue(SV *in, JsonbParseState **jsonb_state, bool is_elem)
 {
 	dTHX;
 	svtype		type;			/* type of incoming object */
-	JsonbValue *out;			/* result */
+	JsonbValue	out;			/* result */
+
+	/* Dereference references recursively. */
+	while (SvROK(in))
+		in = SvRV(in);
 
 	type = SvTYPE(in);
+
 	switch (type)
 	{
 		case SVt_PVAV:
-			out = AV_ToJsonbValue((AV *) in, jsonb_state);
-			break;
+			return AV_ToJsonbValue((AV *) in, jsonb_state);
+
 		case SVt_PVHV:
-			out = HV_ToJsonbValue((HV *) in, jsonb_state);
-			break;
+			return HV_ToJsonbValue((HV *) in, jsonb_state);
+
 		case SVt_NV:
 		case SVt_IV:
 			{
-				if (SvROK(in))
-					/* if "in" is a pointer */
-					out = SV_ToJsonbValue((SV *) SvRV(in), jsonb_state);
-				else
-				{
-					/* if "in" is a numeric */
-					char	   *str;
-					int			i;
-
-					out = palloc(sizeof(JsonbValue));
-					str = sv2cstr(in);
-
-					/*
-					 * We need to lowercase the string because infinity
-					 * representation varies from version to version
-					 */
-					for (i = 0; str[i]; i++)
-						str[i] = tolower(str[i]);
-
-					if (strcmp(str, "inf") == 0)
-						/* in case when variable in is "inf" */
-						ereport(ERROR,
-								(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-								 (errmsg("could not transform to type \"%s\"", "jsonb"),
-								  errdetail("The type you are trying to transform can't be transformed to jsonb"))));
-					else
-					{
-						Datum		tmp;
-
-						tmp = DirectFunctionCall3(numeric_in, CStringGetDatum(str), 0, -1);
-						out->val.numeric = DatumGetNumeric(tmp);
-						out->type = jbvNumeric;
-					}
-				}
-				break;
+				/* if "in" is a numeric */
+				char	   *str = sv2cstr(in);
+				int			i;
+
+				/*
+				 * We need to lowercase the string because infinity
+				 * representation varies from version to version
+				 */
+				for (i = 0; str[i]; i++)
+					str[i] = tolower(str[i]);
+
+				if (strcmp(str, "inf") == 0)
+					/* in case when variable in is "inf" */
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							 (errmsg("could not transform to type \"%s\"", "jsonb"),
+							  errdetail("The type you are trying to transform can't be transformed to jsonb"))));
+
+				out.type = jbvNumeric;
+				out.val.numeric = DatumGetNumeric(
+					DirectFunctionCall3(numeric_in,
+										CStringGetDatum(str), 0, -1));
 			}
+			break;
+
 		case SVt_NULL:
-			out = palloc(sizeof(JsonbValue));
-			out->type = jbvNull;
+			out.type = jbvNull;
 			break;
-		case SVt_PV:
-
-			/*
-			 * String
-			 */
-			out = palloc(sizeof(JsonbValue));
-			out->val.string.val = sv2cstr(in);
-			out->val.string.len = strlen(out->val.string.val);
-			out->type = jbvString;
+
+		case SVt_PV:	/* string */
+			out.type = jbvString;
+			out.val.string.val = sv2cstr(in);
+			out.val.string.len = strlen(out.val.string.val);
 			break;
+
 		default:
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 					 (errmsg("could not transform to type \"%s\"", "jsonb"),
 					  errdetail("The type you are trying to transform can't be transformed to jsonb"))));
-			break;
+			return NULL;
 	}
-	return out;
-}
 
-/*
- * HV_ToJsonbValue
- *
- * Transform Jsonb into SV
- */
-static JsonbValue *
-HV_ToJsonbValue(HV *obj, JsonbParseState *jsonb_state)
-{
-	dTHX;
-	JsonbValue *out;
-	HE		   *he;
-
-	pushJsonbValue(&jsonb_state, WJB_BEGIN_OBJECT, NULL);
-	while ((he = hv_iternext(obj)) != NULL)
-	{
-		JsonbValue *key;
-		JsonbValue *val;
-
-		key = SV_ToJsonbValue(HeSVKEY_force(he), jsonb_state);
-		pushJsonbValue(&jsonb_state, WJB_KEY, key);
-		val = SV_ToJsonbValue(HeVAL(he), jsonb_state);
-		if ((val == NULL) || (IsAJsonbScalar(val)))
-			pushJsonbValue(&jsonb_state, WJB_VALUE, val);
-	}
-	out = pushJsonbValue(&jsonb_state, WJB_END_OBJECT, NULL);
-	return out;
+	/* Push result into 'jsonb_state' unless it is a raw scalar. */
+	return *jsonb_state
+		? pushJsonbValue(jsonb_state, is_elem ? WJB_ELEM : WJB_VALUE, &out)
+		: memcpy(palloc(sizeof(JsonbValue)), &out, sizeof(JsonbValue));
 }
 
 /*
  * plperl_to_jsonb(SV *in)
  *
- * Transform Jsonb into SV
+ * Transform SV into Jsonb
  */
 PG_FUNCTION_INFO_V1(plperl_to_jsonb);
 Datum
 plperl_to_jsonb(PG_FUNCTION_ARGS)
 {
 	dTHX;
-	JsonbValue *out = NULL;
-	Jsonb	   *result;
 	JsonbParseState *jsonb_state = NULL;
-	SV		   *in;
+	SV		   *in = (SV *) PG_GETARG_POINTER(0);
+	JsonbValue *out = SV_ToJsonbValue(in, &jsonb_state, true);
+	Jsonb	   *result = JsonbValueToJsonb(out);
 
-	in = (SV *) PG_GETARG_POINTER(0);
-	out = SV_ToJsonbValue(in, jsonb_state);
-	result = JsonbValueToJsonb(out);
-	PG_RETURN_POINTER(result);
+	PG_RETURN_JSONB_P(result);
 }