go.mod

@@ -3,7 +3,7 @@ module git.frostfs.info/TrueCloudLab/frostfs-sdk-go
 go 1.20
 
 require (
-	git.frostfs.info/TrueCloudLab/frostfs-api-go/v2 v2.16.1-0.20240306101814-c1c7b344b9c0
+	git.frostfs.info/TrueCloudLab/frostfs-api-go/v2 v2.16.1-0.20240319122301-1772b921826b
 	git.frostfs.info/TrueCloudLab/frostfs-contract v0.0.0-20230307110621-19a8ef2d02fb
 	git.frostfs.info/TrueCloudLab/frostfs-crypto v0.6.0
 	git.frostfs.info/TrueCloudLab/hrw v1.2.1
@@ -11,6 +11,7 @@ require (
 	github.com/antlr4-go/antlr/v4 v4.13.0
 	github.com/google/uuid v1.3.0
 	github.com/hashicorp/golang-lru/v2 v2.0.2
+	github.com/klauspost/reedsolomon v1.12.1
 	github.com/mr-tron/base58 v1.2.0
 	github.com/nspcc-dev/neo-go v0.101.2-0.20230601131642-a0117042e8fc
 	github.com/stretchr/testify v1.8.3
@@ -28,6 +29,7 @@ require (
 	github.com/golang/protobuf v1.5.3 // indirect
 	github.com/gorilla/websocket v1.5.0 // indirect
 	github.com/hashicorp/golang-lru v0.6.0 // indirect
+	github.com/klauspost/cpuid/v2 v2.2.6 // indirect
 	github.com/nspcc-dev/go-ordered-json v0.0.0-20220111165707-25110be27d22 // indirect
 	github.com/nspcc-dev/neo-go/pkg/interop v0.0.0-20230615193820-9185820289ce // indirect
 	github.com/nspcc-dev/rfc6979 v0.2.0 // indirect

netmap/netmap.go

@@ -209,6 +209,25 @@ func (m NetMap) SelectFilterNodes(expr *SelectFilterExpr) ([][]NodeInfo, error)
 	return ret, nil
 }
 
+func countNodes(r netmap.Replica) uint32 {
+	if r.GetCount() != 0 {
+		return r.GetCount()
+	}
+	return r.GetECDataCount() + r.GetECParityCount()
+}
+
+func (p PlacementPolicy) isUnique() bool {
+	if p.unique {
+		return true
+	}
+	for _, r := range p.replicas {
+		if r.GetECDataCount() != 0 || r.GetECParityCount() != 0 {
+			return true
+		}
+	}
+	return false
+}
+
 // ContainerNodes returns two-dimensional list of nodes as a result of applying
 // given PlacementPolicy to the NetMap. Each line of the list corresponds to a
 // replica descriptor. Line order corresponds to order of ReplicaDescriptor list
@@ -230,6 +249,7 @@ func (m NetMap) ContainerNodes(p PlacementPolicy, pivot []byte) ([][]NodeInfo, e
 		return nil, err
 	}
 
+	unique := p.isUnique()
 	result := make([][]NodeInfo, len(p.replicas))
 
 	// Note that the cached selectors are not used when the policy contains the UNIQUE flag.
@@ -240,7 +260,7 @@ func (m NetMap) ContainerNodes(p PlacementPolicy, pivot []byte) ([][]NodeInfo, e
 		sName := p.replicas[i].GetSelector()
 		if sName == "" && !(len(p.replicas) == 1 && len(p.selectors) == 1) {
 			var s netmap.Selector
-			s.SetCount(p.replicas[i].GetCount())
+			s.SetCount(countNodes(p.replicas[i]))
 			s.SetFilter(mainFilterName)
 
 			nodes, err := c.getSelection(s)
@@ -250,14 +270,14 @@ func (m NetMap) ContainerNodes(p PlacementPolicy, pivot []byte) ([][]NodeInfo, e
 
 			result[i] = append(result[i], flattenNodes(nodes)...)
 
-			if p.unique {
+			if unique {
 				c.addUsedNodes(result[i]...)
 			}
 
 			continue
 		}
 
-		if p.unique {
+		if unique {
 			if c.processedSelectors[sName] == nil {
 				return nil, fmt.Errorf("selector not found: '%s'", sName)
 			}

netmap/network_info.go

@@ -62,6 +62,8 @@ func (x *NetworkInfo) readFromV2(m netmap.NetworkInfo, checkFieldPresence bool)
 			configEpochDuration,
 			configIRCandidateFee,
 			configMaxObjSize,
+			configMaxECDataCount,
+			configMaxECParityCount,
 			configWithdrawalFee:
 			_, err = decodeConfigValueUint64(prm.GetValue())
 		case configHomomorphicHashingDisabled,
@@ -234,6 +236,8 @@ func (x *NetworkInfo) IterateRawNetworkParameters(f func(name string, value []by
 			configEpochDuration,
 			configIRCandidateFee,
 			configMaxObjSize,
+			configMaxECDataCount,
+			configMaxECParityCount,
 			configWithdrawalFee,
 			configHomomorphicHashingDisabled,
 			configMaintenanceModeAllowed:
@@ -432,6 +436,34 @@ func (x NetworkInfo) MaxObjectSize() uint64 {
 	return x.configUint64(configMaxObjSize)
 }
 
+const configMaxECDataCount = "MaxECDataCount"
+
+// SetMaxECDataCount sets maximum number of data shards for erasure codes.
+//
+// Zero means no restrictions.
+func (x *NetworkInfo) SetMaxECDataCount(dataCount uint64) {
+	x.setConfigUint64(configMaxECDataCount, dataCount)
+}
+
+// MaxECDataCount returns maximum number of data shards for erasure codes.
+func (x NetworkInfo) MaxECDataCount() uint64 {
+	return x.configUint64(configMaxECDataCount)
+}
+
+const configMaxECParityCount = "MaxECParityCount"
+
+// SetMaxECParityCount sets maximum number of parity shards for erasure codes.
+//
+// Zero means no restrictions.
+func (x *NetworkInfo) SetMaxECParityCount(parityCount uint64) {
+	x.setConfigUint64(configMaxECParityCount, parityCount)
+}
+
+// MaxECParityCount returns maximum number of parity shards for erasure codes.
+func (x NetworkInfo) MaxECParityCount() uint64 {
+	return x.configUint64(configMaxECParityCount)
+}
+
 const configWithdrawalFee = "WithdrawFee"
 
 // SetWithdrawalFee sets fee for withdrawals from the FrostFS accounts that

netmap/network_info_test.go

@@ -173,6 +173,32 @@ func TestNetworkInfo_MaxObjectSize(t *testing.T) {
 	)
 }
 
+func TestNetworkInfo_MaxECDataCount(t *testing.T) {
+	testConfigValue(t,
+		func(x NetworkInfo) any { return x.MaxECDataCount() },
+		func(info *NetworkInfo, val any) { info.SetMaxECDataCount(val.(uint64)) },
+		uint64(1), uint64(2),
+		"MaxECDataCount", func(val any) []byte {
+			data := make([]byte, 8)
+			binary.LittleEndian.PutUint64(data, val.(uint64))
+			return data
+		},
+	)
+}
+
+func TestNetworkInfo_MaxECParityCount(t *testing.T) {
+	testConfigValue(t,
+		func(x NetworkInfo) any { return x.MaxECParityCount() },
+		func(info *NetworkInfo, val any) { info.SetMaxECParityCount(val.(uint64)) },
+		uint64(1), uint64(2),
+		"MaxECParityCount", func(val any) []byte {
+			data := make([]byte, 8)
+			binary.LittleEndian.PutUint64(data, val.(uint64))
+			return data
+		},
+	)
+}
+
 func TestNetworkInfo_WithdrawalFee(t *testing.T) {
 	testConfigValue(t,
 		func(x NetworkInfo) any { return x.WithdrawalFee() },

netmap/parser/Query.g4

@@ -4,10 +4,14 @@ options {
     tokenVocab = QueryLexer;
 }
 
-policy: UNIQUE? repStmt+ cbfStmt? selectStmt* filterStmt* EOF;
+policy: UNIQUE? (repStmt | ecStmt)+ cbfStmt? selectStmt* filterStmt* EOF;
 
 selectFilterExpr: cbfStmt? selectStmt? filterStmt* EOF;
 
+ecStmt:
+    EC Data = NUMBER1 DOT Parity = NUMBER1 // erasure code configuration
+    (IN Selector = ident)?;                // optional selector name
+
 repStmt:
     REP Count = NUMBER1     // number of object replicas
     (IN Selector = ident)?; // optional selector name

netmap/parser/QueryLexer.g4

@@ -7,6 +7,7 @@ SIMPLE_OP  : 'EQ' | 'NE' | 'GE' | 'GT' | 'LT' | 'LE';
 
 UNIQUE   : 'UNIQUE';
 REP      : 'REP';
+EC       : 'EC';
 IN       : 'IN';
 AS       : 'AS';
 CBF      : 'CBF';
@@ -14,6 +15,7 @@ SELECT   : 'SELECT';
 FROM     : 'FROM';
 FILTER   : 'FILTER';
 WILDCARD : '*';
+DOT      : '.';
 
 CLAUSE_SAME     : 'SAME';
 CLAUSE_DISTINCT : 'DISTINCT';

netmap/parser/query_base_visitor.go

@@ -1,4 +1,4 @@
-// Code generated from Query.g4 by ANTLR 4.13.0. DO NOT EDIT.
+// Code generated from /repo/frostfs/sdk-go/netmap/parser/Query.g4 by ANTLR 4.13.0. DO NOT EDIT.
 
 package parser // Query
 
@@ -16,6 +16,10 @@ func (v *BaseQueryVisitor) VisitSelectFilterExpr(ctx *SelectFilterExprContext) i
 	return v.VisitChildren(ctx)
 }
 
+func (v *BaseQueryVisitor) VisitEcStmt(ctx *EcStmtContext) interface{} {
+	return v.VisitChildren(ctx)
+}
+
 func (v *BaseQueryVisitor) VisitRepStmt(ctx *RepStmtContext) interface{} {
 	return v.VisitChildren(ctx)
 }

netmap/parser/query_lexer.go

@@ -1,4 +1,4 @@
-// Code generated from QueryLexer.g4 by ANTLR 4.13.0. DO NOT EDIT.
+// Code generated from /repo/frostfs/sdk-go/netmap/parser/QueryLexer.g4 by ANTLR 4.13.0. DO NOT EDIT.
 
 package parser
 
@@ -43,119 +43,123 @@ func querylexerLexerInit() {
 		"DEFAULT_MODE",
 	}
 	staticData.LiteralNames = []string{
-		"", "'NOT'", "'AND'", "'OR'", "", "'UNIQUE'", "'REP'", "'IN'", "'AS'",
+		"", "'NOT'", "'AND'", "'OR'", "", "'UNIQUE'", "'REP'", "'EC'", "'IN'",
-		"'CBF'", "'SELECT'", "'FROM'", "'FILTER'", "'*'", "'SAME'", "'DISTINCT'",
+		"'AS'", "'CBF'", "'SELECT'", "'FROM'", "'FILTER'", "'*'", "'.'", "'SAME'",
-		"'('", "')'", "'@'", "", "", "'0'",
+		"'DISTINCT'", "'('", "')'", "'@'", "", "", "'0'",
 	}
 	staticData.SymbolicNames = []string{
-		"", "NOT_OP", "AND_OP", "OR_OP", "SIMPLE_OP", "UNIQUE", "REP", "IN",
+		"", "NOT_OP", "AND_OP", "OR_OP", "SIMPLE_OP", "UNIQUE", "REP", "EC",
-		"AS", "CBF", "SELECT", "FROM", "FILTER", "WILDCARD", "CLAUSE_SAME",
+		"IN", "AS", "CBF", "SELECT", "FROM", "FILTER", "WILDCARD", "DOT", "CLAUSE_SAME",
 		"CLAUSE_DISTINCT", "L_PAREN", "R_PAREN", "AT", "IDENT", "NUMBER1", "ZERO",
 		"STRING", "WS",
 	}
 	staticData.RuleNames = []string{
-		"NOT_OP", "AND_OP", "OR_OP", "SIMPLE_OP", "UNIQUE", "REP", "IN", "AS",
+		"NOT_OP", "AND_OP", "OR_OP", "SIMPLE_OP", "UNIQUE", "REP", "EC", "IN",
-		"CBF", "SELECT", "FROM", "FILTER", "WILDCARD", "CLAUSE_SAME", "CLAUSE_DISTINCT",
+		"AS", "CBF", "SELECT", "FROM", "FILTER", "WILDCARD", "DOT", "CLAUSE_SAME",
-		"L_PAREN", "R_PAREN", "AT", "IDENT", "Digit", "Nondigit", "NUMBER1",
+		"CLAUSE_DISTINCT", "L_PAREN", "R_PAREN", "AT", "IDENT", "Digit", "Nondigit",
-		"ZERO", "STRING", "ESC", "UNICODE", "HEX", "SAFECODEPOINTSINGLE", "SAFECODEPOINTDOUBLE",
+		"NUMBER1", "ZERO", "STRING", "ESC", "UNICODE", "HEX", "SAFECODEPOINTSINGLE",
-		"WS",
+		"SAFECODEPOINTDOUBLE", "WS",
 	}
 	staticData.PredictionContextCache = antlr.NewPredictionContextCache()
 	staticData.serializedATN = []int32{
-		4, 0, 23, 213, 6, -1, 2, 0, 7, 0, 2, 1, 7, 1, 2, 2, 7, 2, 2, 3, 7, 3, 2,
+		4, 0, 25, 222, 6, -1, 2, 0, 7, 0, 2, 1, 7, 1, 2, 2, 7, 2, 2, 3, 7, 3, 2,
 		4, 7, 4, 2, 5, 7, 5, 2, 6, 7, 6, 2, 7, 7, 7, 2, 8, 7, 8, 2, 9, 7, 9, 2,
 		10, 7, 10, 2, 11, 7, 11, 2, 12, 7, 12, 2, 13, 7, 13, 2, 14, 7, 14, 2, 15,
 		7, 15, 2, 16, 7, 16, 2, 17, 7, 17, 2, 18, 7, 18, 2, 19, 7, 19, 2, 20, 7,
 		20, 2, 21, 7, 21, 2, 22, 7, 22, 2, 23, 7, 23, 2, 24, 7, 24, 2, 25, 7, 25,
-		2, 26, 7, 26, 2, 27, 7, 27, 2, 28, 7, 28, 2, 29, 7, 29, 1, 0, 1, 0, 1,
+		2, 26, 7, 26, 2, 27, 7, 27, 2, 28, 7, 28, 2, 29, 7, 29, 2, 30, 7, 30, 2,
-		0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 3, 1, 3, 1,
+		31, 7, 31, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2,
-		3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 3, 3, 85, 8, 3, 1, 4,
+		1, 2, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3,
-		1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 5, 1, 5, 1, 5, 1, 5, 1, 6, 1, 6,
+		1, 3, 3, 3, 89, 8, 3, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 5, 1,
-		1, 6, 1, 7, 1, 7, 1, 7, 1, 8, 1, 8, 1, 8, 1, 8, 1, 9, 1, 9, 1, 9, 1, 9,
+		5, 1, 5, 1, 5, 1, 6, 1, 6, 1, 6, 1, 7, 1, 7, 1, 7, 1, 8, 1, 8, 1, 8, 1,
-		1, 9, 1, 9, 1, 9, 1, 10, 1, 10, 1, 10, 1, 10, 1, 10, 1, 11, 1, 11, 1, 11,
+		9, 1, 9, 1, 9, 1, 9, 1, 10, 1, 10, 1, 10, 1, 10, 1, 10, 1, 10, 1, 10, 1,
-		1, 11, 1, 11, 1, 11, 1, 11, 1, 12, 1, 12, 1, 13, 1, 13, 1, 13, 1, 13, 1,
+		11, 1, 11, 1, 11, 1, 11, 1, 11, 1, 12, 1, 12, 1, 12, 1, 12, 1, 12, 1, 12,
-		13, 1, 14, 1, 14, 1, 14, 1, 14, 1, 14, 1, 14, 1, 14, 1, 14, 1, 14, 1, 15,
+		1, 12, 1, 13, 1, 13, 1, 14, 1, 14, 1, 15, 1, 15, 1, 15, 1, 15, 1, 15, 1,
-		1, 15, 1, 16, 1, 16, 1, 17, 1, 17, 1, 18, 1, 18, 1, 18, 5, 18, 152, 8,
+		16, 1, 16, 1, 16, 1, 16, 1, 16, 1, 16, 1, 16, 1, 16, 1, 16, 1, 17, 1, 17,
-		18, 10, 18, 12, 18, 155, 9, 18, 1, 19, 1, 19, 1, 20, 1, 20, 1, 21, 1, 21,
+		1, 18, 1, 18, 1, 19, 1, 19, 1, 20, 1, 20, 1, 20, 5, 20, 161, 8, 20, 10,
-		5, 21, 163, 8, 21, 10, 21, 12, 21, 166, 9, 21, 1, 22, 1, 22, 1, 23, 1,
+		20, 12, 20, 164, 9, 20, 1, 21, 1, 21, 1, 22, 1, 22, 1, 23, 1, 23, 5, 23,
-		23, 1, 23, 5, 23, 173, 8, 23, 10, 23, 12, 23, 176, 9, 23, 1, 23, 1, 23,
+		172, 8, 23, 10, 23, 12, 23, 175, 9, 23, 1, 24, 1, 24, 1, 25, 1, 25, 1,
-		1, 23, 1, 23, 5, 23, 182, 8, 23, 10, 23, 12, 23, 185, 9, 23, 1, 23, 3,
+		25, 5, 25, 182, 8, 25, 10, 25, 12, 25, 185, 9, 25, 1, 25, 1, 25, 1, 25,
-		23, 188, 8, 23, 1, 24, 1, 24, 1, 24, 3, 24, 193, 8, 24, 1, 25, 1, 25, 1,
+		1, 25, 5, 25, 191, 8, 25, 10, 25, 12, 25, 194, 9, 25, 1, 25, 3, 25, 197,
-		25, 1, 25, 1, 25, 1, 25, 1, 26, 1, 26, 1, 27, 1, 27, 1, 28, 1, 28, 1, 29,
+		8, 25, 1, 26, 1, 26, 1, 26, 3, 26, 202, 8, 26, 1, 27, 1, 27, 1, 27, 1,
-		4, 29, 208, 8, 29, 11, 29, 12, 29, 209, 1, 29, 1, 29, 0, 0, 30, 1, 1, 3,
+		27, 1, 27, 1, 27, 1, 28, 1, 28, 1, 29, 1, 29, 1, 30, 1, 30, 1, 31, 4, 31,
-		2, 5, 3, 7, 4, 9, 5, 11, 6, 13, 7, 15, 8, 17, 9, 19, 10, 21, 11, 23, 12,
+		217, 8, 31, 11, 31, 12, 31, 218, 1, 31, 1, 31, 0, 0, 32, 1, 1, 3, 2, 5,
-		25, 13, 27, 14, 29, 15, 31, 16, 33, 17, 35, 18, 37, 19, 39, 0, 41, 0, 43,
+		3, 7, 4, 9, 5, 11, 6, 13, 7, 15, 8, 17, 9, 19, 10, 21, 11, 23, 12, 25,
-		20, 45, 21, 47, 22, 49, 0, 51, 0, 53, 0, 55, 0, 57, 0, 59, 23, 1, 0, 8,
+		13, 27, 14, 29, 15, 31, 16, 33, 17, 35, 18, 37, 19, 39, 20, 41, 21, 43,
-		1, 0, 48, 57, 3, 0, 65, 90, 95, 95, 97, 122, 1, 0, 49, 57, 9, 0, 34, 34,
+		0, 45, 0, 47, 22, 49, 23, 51, 24, 53, 0, 55, 0, 57, 0, 59, 0, 61, 0, 63,
-		39, 39, 47, 47, 92, 92, 98, 98, 102, 102, 110, 110, 114, 114, 116, 116,
+		25, 1, 0, 8, 1, 0, 48, 57, 3, 0, 65, 90, 95, 95, 97, 122, 1, 0, 49, 57,
-		3, 0, 48, 57, 65, 70, 97, 102, 3, 0, 0, 31, 39, 39, 92, 92, 3, 0, 0, 31,
+		9, 0, 34, 34, 39, 39, 47, 47, 92, 92, 98, 98, 102, 102, 110, 110, 114,
-		34, 34, 92, 92, 3, 0, 9, 10, 13, 13, 32, 32, 220, 0, 1, 1, 0, 0, 0, 0,
+		114, 116, 116, 3, 0, 48, 57, 65, 70, 97, 102, 3, 0, 0, 31, 39, 39, 92,
-		3, 1, 0, 0, 0, 0, 5, 1, 0, 0, 0, 0, 7, 1, 0, 0, 0, 0, 9, 1, 0, 0, 0, 0,
+		92, 3, 0, 0, 31, 34, 34, 92, 92, 3, 0, 9, 10, 13, 13, 32, 32, 229, 0, 1,
-		11, 1, 0, 0, 0, 0, 13, 1, 0, 0, 0, 0, 15, 1, 0, 0, 0, 0, 17, 1, 0, 0, 0,
+		1, 0, 0, 0, 0, 3, 1, 0, 0, 0, 0, 5, 1, 0, 0, 0, 0, 7, 1, 0, 0, 0, 0, 9,
-		0, 19, 1, 0, 0, 0, 0, 21, 1, 0, 0, 0, 0, 23, 1, 0, 0, 0, 0, 25, 1, 0, 0,
+		1, 0, 0, 0, 0, 11, 1, 0, 0, 0, 0, 13, 1, 0, 0, 0, 0, 15, 1, 0, 0, 0, 0,
-		0, 0, 27, 1, 0, 0, 0, 0, 29, 1, 0, 0, 0, 0, 31, 1, 0, 0, 0, 0, 33, 1, 0,
+		17, 1, 0, 0, 0, 0, 19, 1, 0, 0, 0, 0, 21, 1, 0, 0, 0, 0, 23, 1, 0, 0, 0,
-		0, 0, 0, 35, 1, 0, 0, 0, 0, 37, 1, 0, 0, 0, 0, 43, 1, 0, 0, 0, 0, 45, 1,
+		0, 25, 1, 0, 0, 0, 0, 27, 1, 0, 0, 0, 0, 29, 1, 0, 0, 0, 0, 31, 1, 0, 0,
-		0, 0, 0, 0, 47, 1, 0, 0, 0, 0, 59, 1, 0, 0, 0, 1, 61, 1, 0, 0, 0, 3, 65,
+		0, 0, 33, 1, 0, 0, 0, 0, 35, 1, 0, 0, 0, 0, 37, 1, 0, 0, 0, 0, 39, 1, 0,
-		1, 0, 0, 0, 5, 69, 1, 0, 0, 0, 7, 84, 1, 0, 0, 0, 9, 86, 1, 0, 0, 0, 11,
+		0, 0, 0, 41, 1, 0, 0, 0, 0, 47, 1, 0, 0, 0, 0, 49, 1, 0, 0, 0, 0, 51, 1,
-		93, 1, 0, 0, 0, 13, 97, 1, 0, 0, 0, 15, 100, 1, 0, 0, 0, 17, 103, 1, 0,
+		0, 0, 0, 0, 63, 1, 0, 0, 0, 1, 65, 1, 0, 0, 0, 3, 69, 1, 0, 0, 0, 5, 73,
-		0, 0, 19, 107, 1, 0, 0, 0, 21, 114, 1, 0, 0, 0, 23, 119, 1, 0, 0, 0, 25,
+		1, 0, 0, 0, 7, 88, 1, 0, 0, 0, 9, 90, 1, 0, 0, 0, 11, 97, 1, 0, 0, 0, 13,
-		126, 1, 0, 0, 0, 27, 128, 1, 0, 0, 0, 29, 133, 1, 0, 0, 0, 31, 142, 1,
+		101, 1, 0, 0, 0, 15, 104, 1, 0, 0, 0, 17, 107, 1, 0, 0, 0, 19, 110, 1,
-		0, 0, 0, 33, 144, 1, 0, 0, 0, 35, 146, 1, 0, 0, 0, 37, 148, 1, 0, 0, 0,
+		0, 0, 0, 21, 114, 1, 0, 0, 0, 23, 121, 1, 0, 0, 0, 25, 126, 1, 0, 0, 0,
-		39, 156, 1, 0, 0, 0, 41, 158, 1, 0, 0, 0, 43, 160, 1, 0, 0, 0, 45, 167,
+		27, 133, 1, 0, 0, 0, 29, 135, 1, 0, 0, 0, 31, 137, 1, 0, 0, 0, 33, 142,
-		1, 0, 0, 0, 47, 187, 1, 0, 0, 0, 49, 189, 1, 0, 0, 0, 51, 194, 1, 0, 0,
+		1, 0, 0, 0, 35, 151, 1, 0, 0, 0, 37, 153, 1, 0, 0, 0, 39, 155, 1, 0, 0,
-		0, 53, 200, 1, 0, 0, 0, 55, 202, 1, 0, 0, 0, 57, 204, 1, 0, 0, 0, 59, 207,
+		0, 41, 157, 1, 0, 0, 0, 43, 165, 1, 0, 0, 0, 45, 167, 1, 0, 0, 0, 47, 169,
-		1, 0, 0, 0, 61, 62, 5, 78, 0, 0, 62, 63, 5, 79, 0, 0, 63, 64, 5, 84, 0,
+		1, 0, 0, 0, 49, 176, 1, 0, 0, 0, 51, 196, 1, 0, 0, 0, 53, 198, 1, 0, 0,
-		0, 64, 2, 1, 0, 0, 0, 65, 66, 5, 65, 0, 0, 66, 67, 5, 78, 0, 0, 67, 68,
+		0, 55, 203, 1, 0, 0, 0, 57, 209, 1, 0, 0, 0, 59, 211, 1, 0, 0, 0, 61, 213,
-		5, 68, 0, 0, 68, 4, 1, 0, 0, 0, 69, 70, 5, 79, 0, 0, 70, 71, 5, 82, 0,
+		1, 0, 0, 0, 63, 216, 1, 0, 0, 0, 65, 66, 5, 78, 0, 0, 66, 67, 5, 79, 0,
-		0, 71, 6, 1, 0, 0, 0, 72, 73, 5, 69, 0, 0, 73, 85, 5, 81, 0, 0, 74, 75,
+		0, 67, 68, 5, 84, 0, 0, 68, 2, 1, 0, 0, 0, 69, 70, 5, 65, 0, 0, 70, 71,
-		5, 78, 0, 0, 75, 85, 5, 69, 0, 0, 76, 77, 5, 71, 0, 0, 77, 85, 5, 69, 0,
+		5, 78, 0, 0, 71, 72, 5, 68, 0, 0, 72, 4, 1, 0, 0, 0, 73, 74, 5, 79, 0,
-		0, 78, 79, 5, 71, 0, 0, 79, 85, 5, 84, 0, 0, 80, 81, 5, 76, 0, 0, 81, 85,
+		0, 74, 75, 5, 82, 0, 0, 75, 6, 1, 0, 0, 0, 76, 77, 5, 69, 0, 0, 77, 89,
-		5, 84, 0, 0, 82, 83, 5, 76, 0, 0, 83, 85, 5, 69, 0, 0, 84, 72, 1, 0, 0,
+		5, 81, 0, 0, 78, 79, 5, 78, 0, 0, 79, 89, 5, 69, 0, 0, 80, 81, 5, 71, 0,
-		0, 84, 74, 1, 0, 0, 0, 84, 76, 1, 0, 0, 0, 84, 78, 1, 0, 0, 0, 84, 80,
+		0, 81, 89, 5, 69, 0, 0, 82, 83, 5, 71, 0, 0, 83, 89, 5, 84, 0, 0, 84, 85,
-		1, 0, 0, 0, 84, 82, 1, 0, 0, 0, 85, 8, 1, 0, 0, 0, 86, 87, 5, 85, 0, 0,
+		5, 76, 0, 0, 85, 89, 5, 84, 0, 0, 86, 87, 5, 76, 0, 0, 87, 89, 5, 69, 0,
-		87, 88, 5, 78, 0, 0, 88, 89, 5, 73, 0, 0, 89, 90, 5, 81, 0, 0, 90, 91,
+		0, 88, 76, 1, 0, 0, 0, 88, 78, 1, 0, 0, 0, 88, 80, 1, 0, 0, 0, 88, 82,
-		5, 85, 0, 0, 91, 92, 5, 69, 0, 0, 92, 10, 1, 0, 0, 0, 93, 94, 5, 82, 0,
+		1, 0, 0, 0, 88, 84, 1, 0, 0, 0, 88, 86, 1, 0, 0, 0, 89, 8, 1, 0, 0, 0,
-		0, 94, 95, 5, 69, 0, 0, 95, 96, 5, 80, 0, 0, 96, 12, 1, 0, 0, 0, 97, 98,
+		90, 91, 5, 85, 0, 0, 91, 92, 5, 78, 0, 0, 92, 93, 5, 73, 0, 0, 93, 94,
-		5, 73, 0, 0, 98, 99, 5, 78, 0, 0, 99, 14, 1, 0, 0, 0, 100, 101, 5, 65,
+		5, 81, 0, 0, 94, 95, 5, 85, 0, 0, 95, 96, 5, 69, 0, 0, 96, 10, 1, 0, 0,
-		0, 0, 101, 102, 5, 83, 0, 0, 102, 16, 1, 0, 0, 0, 103, 104, 5, 67, 0, 0,
+		0, 97, 98, 5, 82, 0, 0, 98, 99, 5, 69, 0, 0, 99, 100, 5, 80, 0, 0, 100,
-		104, 105, 5, 66, 0, 0, 105, 106, 5, 70, 0, 0, 106, 18, 1, 0, 0, 0, 107,
+		12, 1, 0, 0, 0, 101, 102, 5, 69, 0, 0, 102, 103, 5, 67, 0, 0, 103, 14,
-		108, 5, 83, 0, 0, 108, 109, 5, 69, 0, 0, 109, 110, 5, 76, 0, 0, 110, 111,
+		1, 0, 0, 0, 104, 105, 5, 73, 0, 0, 105, 106, 5, 78, 0, 0, 106, 16, 1, 0,
-		5, 69, 0, 0, 111, 112, 5, 67, 0, 0, 112, 113, 5, 84, 0, 0, 113, 20, 1,
+		0, 0, 107, 108, 5, 65, 0, 0, 108, 109, 5, 83, 0, 0, 109, 18, 1, 0, 0, 0,
-		0, 0, 0, 114, 115, 5, 70, 0, 0, 115, 116, 5, 82, 0, 0, 116, 117, 5, 79,
+		110, 111, 5, 67, 0, 0, 111, 112, 5, 66, 0, 0, 112, 113, 5, 70, 0, 0, 113,
-		0, 0, 117, 118, 5, 77, 0, 0, 118, 22, 1, 0, 0, 0, 119, 120, 5, 70, 0, 0,
+		20, 1, 0, 0, 0, 114, 115, 5, 83, 0, 0, 115, 116, 5, 69, 0, 0, 116, 117,
-		120, 121, 5, 73, 0, 0, 121, 122, 5, 76, 0, 0, 122, 123, 5, 84, 0, 0, 123,
+		5, 76, 0, 0, 117, 118, 5, 69, 0, 0, 118, 119, 5, 67, 0, 0, 119, 120, 5,
-		124, 5, 69, 0, 0, 124, 125, 5, 82, 0, 0, 125, 24, 1, 0, 0, 0, 126, 127,
+		84, 0, 0, 120, 22, 1, 0, 0, 0, 121, 122, 5, 70, 0, 0, 122, 123, 5, 82,
-		5, 42, 0, 0, 127, 26, 1, 0, 0, 0, 128, 129, 5, 83, 0, 0, 129, 130, 5, 65,
+		0, 0, 123, 124, 5, 79, 0, 0, 124, 125, 5, 77, 0, 0, 125, 24, 1, 0, 0, 0,
-		0, 0, 130, 131, 5, 77, 0, 0, 131, 132, 5, 69, 0, 0, 132, 28, 1, 0, 0, 0,
+		126, 127, 5, 70, 0, 0, 127, 128, 5, 73, 0, 0, 128, 129, 5, 76, 0, 0, 129,
-		133, 134, 5, 68, 0, 0, 134, 135, 5, 73, 0, 0, 135, 136, 5, 83, 0, 0, 136,
+		130, 5, 84, 0, 0, 130, 131, 5, 69, 0, 0, 131, 132, 5, 82, 0, 0, 132, 26,
-		137, 5, 84, 0, 0, 137, 138, 5, 73, 0, 0, 138, 139, 5, 78, 0, 0, 139, 140,
+		1, 0, 0, 0, 133, 134, 5, 42, 0, 0, 134, 28, 1, 0, 0, 0, 135, 136, 5, 46,
-		5, 67, 0, 0, 140, 141, 5, 84, 0, 0, 141, 30, 1, 0, 0, 0, 142, 143, 5, 40,
+		0, 0, 136, 30, 1, 0, 0, 0, 137, 138, 5, 83, 0, 0, 138, 139, 5, 65, 0, 0,
-		0, 0, 143, 32, 1, 0, 0, 0, 144, 145, 5, 41, 0, 0, 145, 34, 1, 0, 0, 0,
+		139, 140, 5, 77, 0, 0, 140, 141, 5, 69, 0, 0, 141, 32, 1, 0, 0, 0, 142,
-		146, 147, 5, 64, 0, 0, 147, 36, 1, 0, 0, 0, 148, 153, 3, 41, 20, 0, 149,
+		143, 5, 68, 0, 0, 143, 144, 5, 73, 0, 0, 144, 145, 5, 83, 0, 0, 145, 146,
-		152, 3, 39, 19, 0, 150, 152, 3, 41, 20, 0, 151, 149, 1, 0, 0, 0, 151, 150,
+		5, 84, 0, 0, 146, 147, 5, 73, 0, 0, 147, 148, 5, 78, 0, 0, 148, 149, 5,
-		1, 0, 0, 0, 152, 155, 1, 0, 0, 0, 153, 151, 1, 0, 0, 0, 153, 154, 1, 0,
+		67, 0, 0, 149, 150, 5, 84, 0, 0, 150, 34, 1, 0, 0, 0, 151, 152, 5, 40,
-		0, 0, 154, 38, 1, 0, 0, 0, 155, 153, 1, 0, 0, 0, 156, 157, 7, 0, 0, 0,
+		0, 0, 152, 36, 1, 0, 0, 0, 153, 154, 5, 41, 0, 0, 154, 38, 1, 0, 0, 0,
-		157, 40, 1, 0, 0, 0, 158, 159, 7, 1, 0, 0, 159, 42, 1, 0, 0, 0, 160, 164,
+		155, 156, 5, 64, 0, 0, 156, 40, 1, 0, 0, 0, 157, 162, 3, 45, 22, 0, 158,
-		7, 2, 0, 0, 161, 163, 3, 39, 19, 0, 162, 161, 1, 0, 0, 0, 163, 166, 1,
+		161, 3, 43, 21, 0, 159, 161, 3, 45, 22, 0, 160, 158, 1, 0, 0, 0, 160, 159,
-		0, 0, 0, 164, 162, 1, 0, 0, 0, 164, 165, 1, 0, 0, 0, 165, 44, 1, 0, 0,
+		1, 0, 0, 0, 161, 164, 1, 0, 0, 0, 162, 160, 1, 0, 0, 0, 162, 163, 1, 0,
-		0, 166, 164, 1, 0, 0, 0, 167, 168, 5, 48, 0, 0, 168, 46, 1, 0, 0, 0, 169,
+		0, 0, 163, 42, 1, 0, 0, 0, 164, 162, 1, 0, 0, 0, 165, 166, 7, 0, 0, 0,
-		174, 5, 34, 0, 0, 170, 173, 3, 49, 24, 0, 171, 173, 3, 57, 28, 0, 172,
+		166, 44, 1, 0, 0, 0, 167, 168, 7, 1, 0, 0, 168, 46, 1, 0, 0, 0, 169, 173,
-		170, 1, 0, 0, 0, 172, 171, 1, 0, 0, 0, 173, 176, 1, 0, 0, 0, 174, 172,
+		7, 2, 0, 0, 170, 172, 3, 43, 21, 0, 171, 170, 1, 0, 0, 0, 172, 175, 1,
-		1, 0, 0, 0, 174, 175, 1, 0, 0, 0, 175, 177, 1, 0, 0, 0, 176, 174, 1, 0,
+		0, 0, 0, 173, 171, 1, 0, 0, 0, 173, 174, 1, 0, 0, 0, 174, 48, 1, 0, 0,
-		0, 0, 177, 188, 5, 34, 0, 0, 178, 183, 5, 39, 0, 0, 179, 182, 3, 49, 24,
+		0, 175, 173, 1, 0, 0, 0, 176, 177, 5, 48, 0, 0, 177, 50, 1, 0, 0, 0, 178,
-		0, 180, 182, 3, 55, 27, 0, 181, 179, 1, 0, 0, 0, 181, 180, 1, 0, 0, 0,
+		183, 5, 34, 0, 0, 179, 182, 3, 53, 26, 0, 180, 182, 3, 61, 30, 0, 181,
-		182, 185, 1, 0, 0, 0, 183, 181, 1, 0, 0, 0, 183, 184, 1, 0, 0, 0, 184,
+		179, 1, 0, 0, 0, 181, 180, 1, 0, 0, 0, 182, 185, 1, 0, 0, 0, 183, 181,
-		186, 1, 0, 0, 0, 185, 183, 1, 0, 0, 0, 186, 188, 5, 39, 0, 0, 187, 169,
+		1, 0, 0, 0, 183, 184, 1, 0, 0, 0, 184, 186, 1, 0, 0, 0, 185, 183, 1, 0,
-		1, 0, 0, 0, 187, 178, 1, 0, 0, 0, 188, 48, 1, 0, 0, 0, 189, 192, 5, 92,
+		0, 0, 186, 197, 5, 34, 0, 0, 187, 192, 5, 39, 0, 0, 188, 191, 3, 53, 26,
-		0, 0, 190, 193, 7, 3, 0, 0, 191, 193, 3, 51, 25, 0, 192, 190, 1, 0, 0,
+		0, 189, 191, 3, 59, 29, 0, 190, 188, 1, 0, 0, 0, 190, 189, 1, 0, 0, 0,
-		0, 192, 191, 1, 0, 0, 0, 193, 50, 1, 0, 0, 0, 194, 195, 5, 117, 0, 0, 195,
+		191, 194, 1, 0, 0, 0, 192, 190, 1, 0, 0, 0, 192, 193, 1, 0, 0, 0, 193,
-		196, 3, 53, 26, 0, 196, 197, 3, 53, 26, 0, 197, 198, 3, 53, 26, 0, 198,
+		195, 1, 0, 0, 0, 194, 192, 1, 0, 0, 0, 195, 197, 5, 39, 0, 0, 196, 178,
-		199, 3, 53, 26, 0, 199, 52, 1, 0, 0, 0, 200, 201, 7, 4, 0, 0, 201, 54,
+		1, 0, 0, 0, 196, 187, 1, 0, 0, 0, 197, 52, 1, 0, 0, 0, 198, 201, 5, 92,
-		1, 0, 0, 0, 202, 203, 8, 5, 0, 0, 203, 56, 1, 0, 0, 0, 204, 205, 8, 6,
+		0, 0, 199, 202, 7, 3, 0, 0, 200, 202, 3, 55, 27, 0, 201, 199, 1, 0, 0,
-		0, 0, 205, 58, 1, 0, 0, 0, 206, 208, 7, 7, 0, 0, 207, 206, 1, 0, 0, 0,
+		0, 201, 200, 1, 0, 0, 0, 202, 54, 1, 0, 0, 0, 203, 204, 5, 117, 0, 0, 204,
-		208, 209, 1, 0, 0, 0, 209, 207, 1, 0, 0, 0, 209, 210, 1, 0, 0, 0, 210,
+		205, 3, 57, 28, 0, 205, 206, 3, 57, 28, 0, 206, 207, 3, 57, 28, 0, 207,
-		211, 1, 0, 0, 0, 211, 212, 6, 29, 0, 0, 212, 60, 1, 0, 0, 0, 12, 0, 84,
+		208, 3, 57, 28, 0, 208, 56, 1, 0, 0, 0, 209, 210, 7, 4, 0, 0, 210, 58,
-		151, 153, 164, 172, 174, 181, 183, 187, 192, 209, 1, 6, 0, 0,
+		1, 0, 0, 0, 211, 212, 8, 5, 0, 0, 212, 60, 1, 0, 0, 0, 213, 214, 8, 6,
+		0, 0, 214, 62, 1, 0, 0, 0, 215, 217, 7, 7, 0, 0, 216, 215, 1, 0, 0, 0,
+		217, 218, 1, 0, 0, 0, 218, 216, 1, 0, 0, 0, 218, 219, 1, 0, 0, 0, 219,
+		220, 1, 0, 0, 0, 220, 221, 6, 31, 0, 0, 221, 64, 1, 0, 0, 0, 12, 0, 88,
+		160, 162, 173, 181, 183, 190, 192, 196, 201, 218, 1, 6, 0, 0,
 	}
 	deserializer := antlr.NewATNDeserializer(nil)
 	staticData.atn = deserializer.Deserialize(staticData.serializedATN)
@@ -202,21 +206,23 @@ const (
 	QueryLexerSIMPLE_OP       = 4
 	QueryLexerUNIQUE          = 5
 	QueryLexerREP             = 6
-	QueryLexerIN              = 7
+	QueryLexerEC              = 7
-	QueryLexerAS              = 8
+	QueryLexerIN              = 8
-	QueryLexerCBF             = 9
+	QueryLexerAS              = 9
-	QueryLexerSELECT          = 10
+	QueryLexerCBF             = 10
-	QueryLexerFROM            = 11
+	QueryLexerSELECT          = 11
-	QueryLexerFILTER          = 12
+	QueryLexerFROM            = 12
-	QueryLexerWILDCARD        = 13
+	QueryLexerFILTER          = 13
-	QueryLexerCLAUSE_SAME     = 14
+	QueryLexerWILDCARD        = 14
-	QueryLexerCLAUSE_DISTINCT = 15
+	QueryLexerDOT             = 15
-	QueryLexerL_PAREN         = 16
+	QueryLexerCLAUSE_SAME     = 16
-	QueryLexerR_PAREN         = 17
+	QueryLexerCLAUSE_DISTINCT = 17
-	QueryLexerAT              = 18
+	QueryLexerL_PAREN         = 18
-	QueryLexerIDENT           = 19
+	QueryLexerR_PAREN         = 19
-	QueryLexerNUMBER1         = 20
+	QueryLexerAT              = 20
-	QueryLexerZERO            = 21
+	QueryLexerIDENT           = 21
-	QueryLexerSTRING          = 22
+	QueryLexerNUMBER1         = 22
-	QueryLexerWS              = 23
+	QueryLexerZERO            = 23
+	QueryLexerSTRING          = 24
+	QueryLexerWS              = 25
 )

netmap/parser/query_visitor.go

@@ -1,4 +1,4 @@
-// Code generated from Query.g4 by ANTLR 4.13.0. DO NOT EDIT.
+// Code generated from /repo/frostfs/sdk-go/netmap/parser/Query.g4 by ANTLR 4.13.0. DO NOT EDIT.
 
 package parser // Query
 
@@ -14,6 +14,9 @@ type QueryVisitor interface {
 	// Visit a parse tree produced by Query#selectFilterExpr.
 	VisitSelectFilterExpr(ctx *SelectFilterExprContext) interface{}
 
+	// Visit a parse tree produced by Query#ecStmt.
+	VisitEcStmt(ctx *EcStmtContext) interface{}
+
 	// Visit a parse tree produced by Query#repStmt.
 	VisitRepStmt(ctx *RepStmtContext) interface{}
 

netmap/policy.go

@@ -34,8 +34,17 @@ type PlacementPolicy struct {
 
 func (p *PlacementPolicy) readFromV2(m netmap.PlacementPolicy, checkFieldPresence bool) error {
 	p.replicas = m.GetReplicas()
-	if checkFieldPresence && len(p.replicas) == 0 {
+	if checkFieldPresence {
-		return errors.New("missing replicas")
+		if len(p.replicas) == 0 {
+			return errors.New("missing replicas")
+		}
+		if len(p.replicas) != 1 {
+			for i := range p.replicas {
+				if p.replicas[i].GetECDataCount() != 0 || p.replicas[i].GetECParityCount() != 0 {
+					return errors.New("erasure code group must be used exclusively")
+				}
+			}
+		}
 	}
 
 	p.backupFactor = m.GetContainerBackupFactor()
@@ -393,10 +402,14 @@ func (p PlacementPolicy) WriteStringTo(w io.StringWriter) (err error) {
 		c := p.replicas[i].GetCount()
 		s := p.replicas[i].GetSelector()
 
-		if s != "" {
+		if c != 0 {
-			_, err = w.WriteString(fmt.Sprintf("%sREP %d IN %s", delim, c, s))
-		} else {
 			_, err = w.WriteString(fmt.Sprintf("%sREP %d", delim, c))
+		} else {
+			ecx, ecy := p.replicas[i].GetECDataCount(), p.replicas[i].GetECParityCount()
+			_, err = w.WriteString(fmt.Sprintf("%sEC %d.%d", delim, ecx, ecy))
+		}
+		if s != "" {
+			_, err = w.WriteString(fmt.Sprintf(" IN %s", s))
 		}
 
 		if err != nil {
@@ -630,6 +643,8 @@ var (
 		"make sure to pair REP and SELECT clauses: \"REP .. IN X\" + \"SELECT ... AS X\"")
 	// errRedundantSelector is returned for errors found by filters policy validator.
 	errRedundantFilter = errors.New("policy: found redundant filter")
+	// errECFewSelectors is returned when EC keyword is used without UNIQUE keyword.
+	errECFewSelectors = errors.New("policy: too few nodes to select")
 )
 
 type policyVisitor struct {
@@ -657,11 +672,18 @@ func (p *policyVisitor) VisitPolicy(ctx *parser.PolicyContext) any {
 
 	pl.unique = ctx.UNIQUE() != nil
 
-	repStmts := ctx.AllRepStmt()
+	stmts := ctx.GetChildren()
-	pl.replicas = make([]netmap.Replica, 0, len(repStmts))
+	for _, r := range stmts {
-
+		var res *netmap.Replica
-	for _, r := range repStmts {
+		var ok bool
-		res, ok := r.Accept(p).(*netmap.Replica)
+		switch r := r.(type) {
+		case parser.IRepStmtContext:
+			res, ok = r.Accept(p).(*netmap.Replica)
+		case parser.IEcStmtContext:
+			res, ok = r.Accept(p).(*netmap.Replica)
+		default:
+			continue
+		}
 		if !ok {
 			return nil
 		}
@@ -758,6 +780,28 @@ func (p *policyVisitor) VisitRepStmt(ctx *parser.RepStmtContext) any {
 	return rs
 }
 
+// VisitRepStmt implements parser.QueryVisitor interface.
+func (p *policyVisitor) VisitEcStmt(ctx *parser.EcStmtContext) any {
+	dataCount, err := strconv.ParseUint(ctx.GetData().GetText(), 10, 32)
+	if err != nil {
+		return p.reportError(errInvalidNumber)
+	}
+	parityCount, err := strconv.ParseUint(ctx.GetParity().GetText(), 10, 32)
+	if err != nil {
+		return p.reportError(errInvalidNumber)
+	}
+
+	rs := new(netmap.Replica)
+	rs.SetECDataCount(uint32(dataCount))
+	rs.SetECParityCount(uint32(parityCount))
+
+	if sel := ctx.GetSelector(); sel != nil {
+		rs.SetSelector(sel.GetText())
+	}
+
+	return rs
+}
+
 // VisitSelectStmt implements parser.QueryVisitor interface.
 func (p *policyVisitor) VisitSelectStmt(ctx *parser.SelectStmtContext) any {
 	res, err := strconv.ParseUint(ctx.GetCount().GetText(), 10, 32)
@@ -910,6 +954,14 @@ func validatePolicy(p PlacementPolicy) error {
 			if seenSelectors[selName] == nil {
 				return fmt.Errorf("%w: '%s'", errUnknownSelector, selName)
 			}
+
+			dataCount := p.replicas[i].GetECDataCount()
+			parityCount := p.replicas[i].GetECParityCount()
+			if dataCount != 0 || parityCount != 0 {
+				if c := seenSelectors[selName].GetCount(); c < dataCount+parityCount {
+					return fmt.Errorf("%w: %d < %d + %d", errECFewSelectors, c, dataCount, parityCount)
+				}
+			}
 		}
 	}
 

netmap/policy_decode_test.go

@@ -44,6 +44,8 @@ FILTER Node EQ '10.78.8.11' AS F`,
 		`UNIQUE
 REP 1
 REP 1`,
+		`EC 1.2 IN X
+SELECT 3 IN City FROM * AS X`,
 	}
 
 	var p PlacementPolicy

object/erasure_code.go

@@ -0,0 +1,121 @@
+package object
+
+import (
+	"errors"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/object"
+	refs "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/refs"
+	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
+)
+
+// ECHeader represents erasure coding header.
+type ECHeader struct {
+	parent       oid.ID
+	index        uint32
+	total        uint32
+	header       []byte
+	headerLength uint32
+}
+
+// NewECHeader constructs new erasure coding header.
+func NewECHeader(parent oid.ID, index, total uint32, header []byte, headerLength uint32) *ECHeader {
+	return &ECHeader{
+		parent:       parent,
+		index:        index,
+		total:        total,
+		header:       header,
+		headerLength: headerLength,
+	}
+}
+
+// WriteToV2 converts SDK structure to v2-api one.
+func (e *ECHeader) WriteToV2(h *object.ECHeader) {
+	var parent refs.ObjectID
+	e.parent.WriteToV2(&parent)
+	h.Parent = &parent
+	h.Index = e.index
+	h.Total = e.total
+	h.Header = e.header
+	h.HeaderLength = e.headerLength
+}
+
+// ReadFromV2 converts v2-api structure to SDK one.
+func (e *ECHeader) ReadFromV2(h *object.ECHeader) error {
+	if h == nil {
+		return nil
+	}
+	if h.Parent == nil {
+		return errors.New("empty parent")
+	}
+
+	_ = e.parent.ReadFromV2(*h.Parent)
+	e.index = h.Index
+	e.total = h.Total
+	e.header = h.Header
+	e.headerLength = h.HeaderLength
+	return nil
+}
+
+func (o *Object) ECHeader() *ECHeader {
+	ec := (*object.Object)(o).GetHeader().GetEC()
+	if ec == nil {
+		return nil
+	}
+
+	h := new(ECHeader)
+	_ = h.ReadFromV2(ec)
+	return h
+}
+
+func (o *Object) SetECHeader(ec *ECHeader) {
+	o.setHeaderField(func(h *object.Header) {
+		if ec == nil {
+			h.SetEC(nil)
+			return
+		}
+
+		v2 := new(object.ECHeader)
+		ec.WriteToV2(v2)
+		h.SetEC(v2)
+	})
+}
+
+func (e *ECHeader) Parent() oid.ID {
+	return e.parent
+}
+
+func (e *ECHeader) SetParent(id oid.ID) {
+	e.parent = id
+}
+
+func (e *ECHeader) Index() uint32 {
+	return e.index
+}
+
+func (e *ECHeader) SetIndex(i uint32) {
+	e.index = i
+}
+
+func (e *ECHeader) Total() uint32 {
+	return e.total
+}
+
+func (e *ECHeader) SetTotal(i uint32) {
+	e.total = i
+}
+
+func (e *ECHeader) Header() []byte {
+	return e.header
+}
+
+func (e *ECHeader) SetHeader(header []byte) {
+	e.header = header
+}
+
+func (e *ECHeader) HeaderLength() uint32 {
+	return e.headerLength
+}
+
+func (e *ECHeader) SetHeaderLength(l uint32) {
+	e.headerLength = l
+}

object/erasurecode/constructor.go

@@ -0,0 +1,87 @@
+package erasurecode
+
+import (
+	"errors"
+
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	"github.com/klauspost/reedsolomon"
+)
+
+var (
+	// ErrMalformedSlice is returned when a slice of EC chunks is inconsistent.
+	ErrMalformedSlice = errors.New("inconsistent EC headers")
+	// ErrInvShardNum is returned from NewConstructor when the number of shards is invalid.
+	ErrInvShardNum = reedsolomon.ErrInvShardNum
+	// ErrMaxShardNum is returned from NewConstructor when the number of shards is too big.
+	ErrMaxShardNum = reedsolomon.ErrMaxShardNum
+)
+
+// MaxShardCount is the maximum number of shards.
+const MaxShardCount = 256
+
+// Constructor is a wrapper around encoder allowing to reconstruct objects.
+// It's methods are not thread-safe.
+type Constructor struct {
+	enc           reedsolomon.Encoder
+	headerLength  uint32
+	payloadShards [][]byte
+	headerShards  [][]byte
+}
+
+// NewConstructor returns new constructor instance.
+func NewConstructor(dataCount int, parityCount int) (*Constructor, error) {
+	// The library supports up to 65536 shards with some restrictions.
+	// This can easily result in OOM or panic, thus SDK declares it's own restriction.
+	if dataCount+parityCount > MaxShardCount {
+		return nil, ErrMaxShardNum
+	}
+
+	enc, err := reedsolomon.New(dataCount, parityCount)
+	if err != nil {
+		return nil, err
+	}
+	return &Constructor{enc: enc}, nil
+}
+
+// clear clears internal state of the constructor, so it can be reused.
+func (c *Constructor) clear() {
+	c.headerLength = 0
+	c.payloadShards = nil
+	c.headerShards = nil
+}
+
+func (c *Constructor) fillHeader(parts []*objectSDK.Object) error {
+	shards := make([][]byte, len(parts))
+	headerLength := 0
+	for i := range parts {
+		if parts[i] == nil {
+			continue
+		}
+
+		var err error
+		headerLength, err = validatePart(parts, i, headerLength)
+		if err != nil {
+			return err
+		}
+
+		shards[i] = parts[i].GetECHeader().Header()
+	}
+
+	c.headerLength = uint32(headerLength)
+	c.headerShards = shards
+	return nil
+}
+
+// fillPayload fills the payload shards.
+// Currently there is no case when it can be called without reconstructing header,
+// thus fillHeader() must be called before and this function performs no validation.
+func (c *Constructor) fillPayload(parts []*objectSDK.Object) {
+	shards := make([][]byte, len(parts))
+	for i := range parts {
+		if parts[i] == nil {
+			continue
+		}
+		shards[i] = parts[i].Payload()
+	}
+	c.payloadShards = shards
+}

object/erasurecode/constructor_test.go

@@ -0,0 +1,31 @@
+package erasurecode_test
+
+import (
+	"testing"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/erasurecode"
+	"github.com/stretchr/testify/require"
+)
+
+func TestErasureConstruct(t *testing.T) {
+	t.Run("negative, no panic", func(t *testing.T) {
+		_, err := erasurecode.NewConstructor(-1, 2)
+		require.ErrorIs(t, err, erasurecode.ErrInvShardNum)
+	})
+	t.Run("negative, no panic", func(t *testing.T) {
+		_, err := erasurecode.NewConstructor(2, -1)
+		require.ErrorIs(t, err, erasurecode.ErrInvShardNum)
+	})
+	t.Run("zero parity", func(t *testing.T) {
+		_, err := erasurecode.NewConstructor(1, 0)
+		require.NoError(t, err)
+	})
+	t.Run("max shard num", func(t *testing.T) {
+		_, err := erasurecode.NewConstructor(erasurecode.MaxShardCount, 0)
+		require.NoError(t, err)
+	})
+	t.Run("max+1 shard num", func(t *testing.T) {
+		_, err := erasurecode.NewConstructor(erasurecode.MaxShardCount+1, 0)
+		require.ErrorIs(t, err, erasurecode.ErrMaxShardNum)
+	})
+}

object/erasurecode/reconstruct.go

@@ -0,0 +1,142 @@
+package erasurecode
+
+import (
+	"bytes"
+	"crypto/ecdsa"
+	"fmt"
+
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	"github.com/klauspost/reedsolomon"
+)
+
+// Reconstruct returns full object reconstructed from parts.
+// All non-nil objects in parts must have EC header with the same `total` field equal to len(parts).
+// The slice must contain at least one non nil object.
+// Index of the objects in parts must be equal to it's index field in the EC header.
+// The parts slice isn't changed and can be used concurrently for reading.
+func (c *Constructor) Reconstruct(parts []*objectSDK.Object) (*objectSDK.Object, error) {
+	res, err := c.ReconstructHeader(parts)
+	if err != nil {
+		return nil, err
+	}
+
+	c.fillPayload(parts)
+
+	payload, err := reconstructExact(c.enc, int(res.PayloadSize()), c.payloadShards)
+	if err != nil {
+		return nil, fmt.Errorf("%w: %w", ErrMalformedSlice, err)
+	}
+
+	res.SetPayload(payload)
+	return res, nil
+}
+
+// ReconstructHeader returns object header reconstructed from parts.
+// All non-nil objects in parts must have EC header with the same `total` field equal to len(parts).
+// The slice must contain at least one non nil object.
+// Index of the objects in parts must be equal to it's index field in the EC header.
+// The parts slice isn't changed and can be used concurrently for reading.
+func (c *Constructor) ReconstructHeader(parts []*objectSDK.Object) (*objectSDK.Object, error) {
+	c.clear()
+
+	if err := c.fillHeader(parts); err != nil {
+		return nil, err
+	}
+
+	obj, err := c.reconstructHeader()
+	if err != nil {
+		return nil, fmt.Errorf("%w: %w", ErrMalformedSlice, err)
+	}
+	return obj, nil
+}
+
+// ReconstructParts reconstructs specific EC parts without reconstructing full object.
+// All non-nil objects in parts must have EC header with the same `total` field equal to len(parts).
+// The slice must contain at least one non nil object.
+// Index of the objects in parts must be equal to it's index field in the EC header.
+// Those parts for which corresponding element in required is true must be nil and will be overwritten.
+// Because partial reconstruction only makes sense for full objects, all parts must have non-empty payload.
+// If key is not nil, all reconstructed parts are signed with this key.
+func (c *Constructor) ReconstructParts(parts []*objectSDK.Object, required []bool, key *ecdsa.PrivateKey) error {
+	if len(required) != len(parts) {
+		return fmt.Errorf("len(parts) != len(required): %d != %d", len(parts), len(required))
+	}
+
+	c.clear()
+
+	if err := c.fillHeader(parts); err != nil {
+		return err
+	}
+	c.fillPayload(parts)
+
+	if err := c.enc.ReconstructSome(c.payloadShards, required); err != nil {
+		return fmt.Errorf("%w: %w", ErrMalformedSlice, err)
+	}
+	if err := c.enc.ReconstructSome(c.headerShards, required); err != nil {
+		return fmt.Errorf("%w: %w", ErrMalformedSlice, err)
+	}
+
+	nonNilPart := 0
+	for i := range parts {
+		if parts[i] != nil {
+			nonNilPart = i
+			break
+		}
+	}
+
+	ec := parts[nonNilPart].GetECHeader()
+	parent := ec.Parent()
+	total := ec.Total()
+
+	for i := range required {
+		if parts[i] != nil || !required[i] {
+			continue
+		}
+
+		part := objectSDK.New()
+		copyRequiredFields(part, parts[nonNilPart])
+		part.SetPayload(c.payloadShards[i])
+		part.SetPayloadSize(uint64(len(c.payloadShards[i])))
+		part.SetECHeader(objectSDK.NewECHeader(parent, uint32(i), total,
+			c.headerShards[i], c.headerLength))
+
+		if err := setIDWithSignature(part, key); err != nil {
+			return err
+		}
+		parts[i] = part
+	}
+	return nil
+}
+
+func (c *Constructor) reconstructHeader() (*objectSDK.Object, error) {
+	data, err := reconstructExact(c.enc, int(c.headerLength), c.headerShards)
+	if err != nil {
+		return nil, err
+	}
+
+	var obj objectSDK.Object
+	return &obj, obj.Unmarshal(data)
+}
+
+func reconstructExact(enc reedsolomon.Encoder, size int, shards [][]byte) ([]byte, error) {
+	if err := enc.ReconstructData(shards); err != nil {
+		return nil, err
+	}
+
+	// Technically, this error will be returned from enc.Join().
+	// However, allocating based on unvalidated user data is an easy attack vector.
+	// Preallocating seems to have enough benefits to justify a slight increase in code complexity.
+	maxSize := 0
+	for i := range shards {
+		maxSize += len(shards[i])
+	}
+	if size > maxSize {
+		return nil, reedsolomon.ErrShortData
+	}
+
+	buf := bytes.NewBuffer(make([]byte, 0, size))
+	if err := enc.Join(buf, shards, size); err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}

object/erasurecode/reconstruct_test.go

@@ -0,0 +1,284 @@
+package erasurecode_test
+
+import (
+	"context"
+	"crypto/rand"
+	"math"
+	"testing"
+
+	cidtest "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id/test"
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/erasurecode"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/transformer"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/user"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/version"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
+	"github.com/stretchr/testify/require"
+)
+
+func TestErasureCodeReconstruct(t *testing.T) {
+	const payloadSize = 99
+	const dataCount = 3
+	const parityCount = 2
+
+	// We would also like to test padding behaviour,
+	// so ensure padding is done.
+	require.NotZero(t, payloadSize%(dataCount+parityCount))
+
+	pk, err := keys.NewPrivateKey()
+	require.NoError(t, err)
+
+	original := newObject(t, payloadSize, pk)
+
+	c, err := erasurecode.NewConstructor(dataCount, parityCount)
+	require.NoError(t, err)
+
+	parts, err := c.Split(original, &pk.PrivateKey)
+	require.NoError(t, err)
+
+	t.Run("reconstruct header", func(t *testing.T) {
+		original := original.CutPayload()
+		parts := cloneSlice(parts)
+		for i := range parts {
+			parts[i] = parts[i].CutPayload()
+		}
+		t.Run("from data", func(t *testing.T) {
+			parts := cloneSlice(parts)
+			for i := dataCount; i < dataCount+parityCount; i++ {
+				parts[i] = nil
+			}
+			reconstructed, err := c.ReconstructHeader(parts)
+			require.NoError(t, err)
+			verifyReconstruction(t, original, reconstructed)
+		})
+		t.Run("from parity", func(t *testing.T) {
+			parts := cloneSlice(parts)
+			for i := 0; i < parityCount; i++ {
+				parts[i] = nil
+			}
+			reconstructed, err := c.ReconstructHeader(parts)
+			require.NoError(t, err)
+			verifyReconstruction(t, original, reconstructed)
+
+			t.Run("not enough shards", func(t *testing.T) {
+				parts[parityCount] = nil
+				_, err := c.ReconstructHeader(parts)
+				require.ErrorIs(t, err, erasurecode.ErrMalformedSlice)
+			})
+		})
+		t.Run("only nil parts", func(t *testing.T) {
+			parts := make([]*objectSDK.Object, len(parts))
+			_, err := c.ReconstructHeader(parts)
+			require.ErrorIs(t, err, erasurecode.ErrMalformedSlice)
+		})
+		t.Run("missing EC header", func(t *testing.T) {
+			parts := cloneSlice(parts)
+			parts[0] = deepCopy(t, parts[0])
+			parts[0].SetECHeader(nil)
+
+			_, err := c.ReconstructHeader(parts)
+			require.ErrorIs(t, err, erasurecode.ErrMalformedSlice)
+		})
+		t.Run("invalid index", func(t *testing.T) {
+			parts := cloneSlice(parts)
+			parts[0] = deepCopy(t, parts[0])
+
+			ec := parts[0].GetECHeader()
+			ec.SetIndex(1)
+			parts[0].SetECHeader(ec)
+
+			_, err := c.ReconstructHeader(parts)
+			require.ErrorIs(t, err, erasurecode.ErrMalformedSlice)
+		})
+		t.Run("invalid total", func(t *testing.T) {
+			parts := cloneSlice(parts)
+			parts[0] = deepCopy(t, parts[0])
+
+			ec := parts[0].GetECHeader()
+			ec.SetTotal(uint32(len(parts) + 1))
+			parts[0].SetECHeader(ec)
+
+			_, err := c.ReconstructHeader(parts)
+			require.ErrorIs(t, err, erasurecode.ErrMalformedSlice)
+		})
+		t.Run("inconsistent header length", func(t *testing.T) {
+			parts := cloneSlice(parts)
+			parts[0] = deepCopy(t, parts[0])
+
+			ec := parts[0].GetECHeader()
+			ec.SetHeaderLength(ec.HeaderLength() - 1)
+			parts[0].SetECHeader(ec)
+
+			_, err := c.ReconstructHeader(parts)
+			require.ErrorIs(t, err, erasurecode.ErrMalformedSlice)
+		})
+		t.Run("invalid header length", func(t *testing.T) {
+			parts := cloneSlice(parts)
+			for i := range parts {
+				parts[i] = deepCopy(t, parts[i])
+
+				ec := parts[0].GetECHeader()
+				ec.SetHeaderLength(math.MaxUint32)
+				parts[0].SetECHeader(ec)
+			}
+
+			_, err := c.ReconstructHeader(parts)
+			require.ErrorIs(t, err, erasurecode.ErrMalformedSlice)
+		})
+	})
+	t.Run("reconstruct data", func(t *testing.T) {
+		t.Run("from data", func(t *testing.T) {
+			parts := cloneSlice(parts)
+			for i := dataCount; i < dataCount+parityCount; i++ {
+				parts[i] = nil
+			}
+			reconstructed, err := c.Reconstruct(parts)
+			require.NoError(t, err)
+			verifyReconstruction(t, original, reconstructed)
+		})
+		t.Run("from parity", func(t *testing.T) {
+			parts := cloneSlice(parts)
+			for i := 0; i < parityCount; i++ {
+				parts[i] = nil
+			}
+			reconstructed, err := c.Reconstruct(parts)
+			require.NoError(t, err)
+			verifyReconstruction(t, original, reconstructed)
+
+			t.Run("not enough shards", func(t *testing.T) {
+				parts[parityCount] = nil
+				_, err := c.Reconstruct(parts)
+				require.ErrorIs(t, err, erasurecode.ErrMalformedSlice)
+			})
+		})
+	})
+	t.Run("reconstruct parts", func(t *testing.T) {
+		// We would like to also test that ReconstructParts doesn't perform
+		// excessive work, so ensure this test makes sense.
+		require.GreaterOrEqual(t, parityCount, 2)
+
+		t.Run("from data", func(t *testing.T) {
+			oldParts := parts
+			parts := cloneSlice(parts)
+			for i := dataCount; i < dataCount+parityCount; i++ {
+				parts[i] = nil
+			}
+
+			required := make([]bool, len(parts))
+			required[dataCount] = true
+
+			require.NoError(t, c.ReconstructParts(parts, required, nil))
+
+			old := deepCopy(t, oldParts[dataCount])
+			old.SetSignature(nil)
+			require.Equal(t, old, parts[dataCount])
+
+			for i := dataCount + 1; i < dataCount+parityCount; i++ {
+				require.Nil(t, parts[i])
+			}
+		})
+		t.Run("from parity", func(t *testing.T) {
+			oldParts := parts
+			parts := cloneSlice(parts)
+			for i := 0; i < parityCount; i++ {
+				parts[i] = nil
+			}
+
+			required := make([]bool, len(parts))
+			required[0] = true
+
+			require.NoError(t, c.ReconstructParts(parts, required, nil))
+
+			old := deepCopy(t, oldParts[0])
+			old.SetSignature(nil)
+			require.Equal(t, old, parts[0])
+
+			for i := 1; i < parityCount; i++ {
+				require.Nil(t, parts[i])
+			}
+		})
+	})
+}
+
+func newObject(t *testing.T, size uint64, pk *keys.PrivateKey) *objectSDK.Object {
+	// Use transformer to form object to avoid potential bugs with yet another helper object creation in tests.
+	tt := &testTarget{}
+	p := transformer.NewPayloadSizeLimiter(transformer.Params{
+		Key:                    &pk.PrivateKey,
+		NextTargetInit:         func() transformer.ObjectWriter { return tt },
+		NetworkState:           dummyEpochSource(123),
+		MaxSize:                size + 1,
+		WithoutHomomorphicHash: true,
+	})
+	cnr := cidtest.ID()
+	ver := version.Current()
+	hdr := objectSDK.New()
+	hdr.SetContainerID(cnr)
+	hdr.SetType(objectSDK.TypeRegular)
+	hdr.SetVersion(&ver)
+
+	var owner user.ID
+	user.IDFromKey(&owner, pk.PrivateKey.PublicKey)
+	hdr.SetOwnerID(owner)
+
+	var attr objectSDK.Attribute
+	attr.SetKey("somekey")
+	attr.SetValue("somevalue")
+	hdr.SetAttributes(attr)
+
+	expectedPayload := make([]byte, size)
+	_, _ = rand.Read(expectedPayload)
+	writeObject(t, context.Background(), p, hdr, expectedPayload)
+	require.Len(t, tt.objects, 1)
+	return tt.objects[0]
+}
+
+func writeObject(t *testing.T, ctx context.Context, target transformer.ChunkedObjectWriter, header *objectSDK.Object, payload []byte) *transformer.AccessIdentifiers {
+	require.NoError(t, target.WriteHeader(ctx, header))
+
+	_, err := target.Write(ctx, payload)
+	require.NoError(t, err)
+
+	ids, err := target.Close(ctx)
+	require.NoError(t, err)
+
+	return ids
+}
+
+func verifyReconstruction(t *testing.T, original, reconstructed *objectSDK.Object) {
+	require.True(t, reconstructed.VerifyIDSignature())
+	reconstructed.ToV2().SetMarshalData(nil)
+	original.ToV2().SetMarshalData(nil)
+
+	require.Equal(t, original, reconstructed)
+}
+
+func deepCopy(t *testing.T, obj *objectSDK.Object) *objectSDK.Object {
+	data, err := obj.Marshal()
+	require.NoError(t, err)
+
+	res := objectSDK.New()
+	require.NoError(t, res.Unmarshal(data))
+	return res
+}
+
+func cloneSlice[T any](src []T) []T {
+	dst := make([]T, len(src))
+	copy(dst, src)
+	return dst
+}
+
+type dummyEpochSource uint64
+
+func (s dummyEpochSource) CurrentEpoch() uint64 {
+	return uint64(s)
+}
+
+type testTarget struct {
+	objects []*objectSDK.Object
+}
+
+func (tt *testTarget) WriteObject(_ context.Context, o *objectSDK.Object) error {
+	tt.objects = append(tt.objects, o)
+	return nil // AccessIdentifiers should not be used.
+}

object/erasurecode/split.go

@@ -0,0 +1,69 @@
+package erasurecode
+
+import (
+	"crypto/ecdsa"
+
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+)
+
+// Split splits fully formed object into multiple chunks.
+func (c *Constructor) Split(obj *objectSDK.Object, key *ecdsa.PrivateKey) ([]*objectSDK.Object, error) {
+	c.clear()
+
+	header, err := obj.CutPayload().Marshal()
+	if err != nil {
+		return nil, err
+	}
+
+	headerShards, err := c.encodeRaw(header)
+	if err != nil {
+		return nil, err
+	}
+	payloadShards, err := c.encodeRaw(obj.Payload())
+	if err != nil {
+		return nil, err
+	}
+
+	parts := make([]*objectSDK.Object, len(payloadShards))
+	parent, _ := obj.ID()
+	for i := range parts {
+		chunk := objectSDK.New()
+		copyRequiredFields(chunk, obj)
+		chunk.SetPayload(payloadShards[i])
+		chunk.SetPayloadSize(uint64(len(payloadShards[i])))
+
+		ec := objectSDK.NewECHeader(parent, uint32(i), uint32(len(payloadShards)), headerShards[i], uint32(len(header)))
+		chunk.SetECHeader(ec)
+		if err := setIDWithSignature(chunk, key); err != nil {
+			return nil, err
+		}
+
+		parts[i] = chunk
+	}
+	return parts, nil
+}
+
+func setIDWithSignature(obj *objectSDK.Object, key *ecdsa.PrivateKey) error {
+	if err := objectSDK.CalculateAndSetID(obj); err != nil {
+		return err
+	}
+
+	objectSDK.CalculateAndSetPayloadChecksum(obj)
+
+	if key == nil {
+		return nil
+	}
+
+	return objectSDK.CalculateAndSetSignature(*key, obj)
+}
+
+func (c *Constructor) encodeRaw(data []byte) ([][]byte, error) {
+	shards, err := c.enc.Split(data)
+	if err != nil {
+		return nil, err
+	}
+	if err := c.enc.Encode(shards); err != nil {
+		return nil, err
+	}
+	return shards, nil
+}

object/erasurecode/split_test.go

@@ -0,0 +1,36 @@
+package erasurecode_test
+
+import (
+	"testing"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/erasurecode"
+	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
+	"github.com/stretchr/testify/require"
+)
+
+// The library can behave differently for big shard counts.
+// This test checks we support the maximum number of chunks we promise.
+func TestSplitMaxShardCount(t *testing.T) {
+	pk, err := keys.NewPrivateKey()
+	require.NoError(t, err)
+
+	original := newObject(t, 1024, pk)
+
+	t.Run("only data", func(t *testing.T) {
+		c, err := erasurecode.NewConstructor(erasurecode.MaxShardCount, 0)
+		require.NoError(t, err)
+
+		parts, err := c.Split(original, &pk.PrivateKey)
+		require.NoError(t, err)
+		require.Len(t, parts, erasurecode.MaxShardCount)
+	})
+	t.Run("data + parity", func(t *testing.T) {
+		c, err := erasurecode.NewConstructor(1, erasurecode.MaxShardCount-1)
+		require.NoError(t, err)
+
+		parts, err := c.Split(original, &pk.PrivateKey)
+		require.NoError(t, err)
+		require.Len(t, parts, erasurecode.MaxShardCount)
+	})
+
+}

object/erasurecode/target.go

@@ -0,0 +1,44 @@
+package erasurecode
+
+import (
+	"context"
+	"crypto/ecdsa"
+
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/transformer"
+)
+
+// Target accepts regular objects and splits them into erasure-coded chunks.
+type Target struct {
+	c    *Constructor
+	key  *ecdsa.PrivateKey
+	next transformer.ObjectWriter
+}
+
+// ObjectWriter is an interface of the object writer that writes prepared object.
+type ObjectWriter interface {
+	WriteObject(context.Context, *objectSDK.Object) error
+}
+
+// NewTarget returns new target instance.
+func NewTarget(c *Constructor, key *ecdsa.PrivateKey, next ObjectWriter) *Target {
+	return &Target{
+		c:    c,
+		key:  key,
+		next: next,
+	}
+}
+
+// WriteObject implements the transformer.ObjectWriter interface.
+func (t *Target) WriteObject(ctx context.Context, obj *objectSDK.Object) error {
+	parts, err := t.c.Split(obj, t.key)
+	if err != nil {
+		return err
+	}
+	for i := range parts {
+		if err := t.next.WriteObject(ctx, parts[i]); err != nil {
+			return err
+		}
+	}
+	return nil
+}

object/erasurecode/verify.go

@@ -0,0 +1,104 @@
+package erasurecode
+
+import (
+	"fmt"
+
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+)
+
+// Verify verifies that parts are well formed.
+// All parts are expected to be non-nil.
+// The number of parts must be equal to `total` field of the EC header
+// and parts must be sorted by index.
+func (c *Constructor) Verify(parts []*objectSDK.Object) error {
+	c.clear()
+
+	var headerLength int
+	for i := range parts {
+		if parts[i] == nil {
+			return ErrMalformedSlice
+		}
+
+		var err error
+		headerLength, err = validatePart(parts, i, headerLength)
+		if err != nil {
+			return err
+		}
+	}
+
+	p0 := parts[0]
+	for i := 1; i < len(parts); i++ {
+		// This part must be kept in sync with copyRequiredFields().
+		pi := parts[i]
+		if p0.OwnerID().Equals(pi.OwnerID()) {
+			return fmt.Errorf("%w: owner id mismatch: %s != %s", ErrMalformedSlice, p0.OwnerID(), pi.OwnerID())
+		}
+		if p0.Version() == nil && pi.Version() != nil || !p0.Version().Equal(*pi.Version()) {
+			return fmt.Errorf("%w: version mismatch: %s != %s", ErrMalformedSlice, p0.Version(), pi.Version())
+		}
+
+		cnr0, _ := p0.ContainerID()
+		cnri, _ := pi.ContainerID()
+		if !cnr0.Equals(cnri) {
+			return fmt.Errorf("%w: container id mismatch: %s != %s", ErrMalformedSlice, cnr0, cnri)
+		}
+	}
+
+	if err := c.fillHeader(parts); err != nil {
+		return err
+	}
+	c.fillPayload(parts)
+
+	ok, err := c.enc.Verify(c.headerShards)
+	if err != nil {
+		return err
+	}
+	if !ok {
+		return ErrMalformedSlice
+	}
+
+	ok, err = c.enc.Verify(c.payloadShards)
+	if err != nil {
+		return err
+	}
+	if !ok {
+		return ErrMalformedSlice
+	}
+	return nil
+}
+
+// copyRequiredFields sets all fields in dst which are copied from src and shared among all chunks.
+// src can be either another chunk of full object.
+// dst must be a chunk.
+func copyRequiredFields(dst *objectSDK.Object, src *objectSDK.Object) {
+	dst.SetVersion(src.Version())
+	dst.SetOwnerID(src.OwnerID())
+	dst.SetCreationEpoch(src.CreationEpoch())
+	dst.SetSessionToken(src.SessionToken())
+
+	cnr, _ := src.ContainerID()
+	dst.SetContainerID(cnr)
+}
+
+// validatePart makes i-th part is consistent with the rest.
+// If headerLength is not zero it is asserted to be equal in the ec header.
+// Otherwise, new headerLength is returned.
+func validatePart(parts []*objectSDK.Object, i int, headerLength int) (int, error) {
+	ec := parts[i].GetECHeader()
+	if ec == nil {
+		return headerLength, fmt.Errorf("%w: missing EC header", ErrMalformedSlice)
+	}
+	if ec.Index() != uint32(i) {
+		return headerLength, fmt.Errorf("%w: index=%d, ec.index=%d", ErrMalformedSlice, i, ec.Index())
+	}
+	if ec.Total() != uint32(len(parts)) {
+		return headerLength, fmt.Errorf("%w: len(parts)=%d, total=%d", ErrMalformedSlice, len(parts), ec.Total())
+	}
+	if headerLength == 0 {
+		return int(ec.HeaderLength()), nil
+	}
+	if ec.HeaderLength() != uint32(headerLength) {
+		return headerLength, fmt.Errorf("%w: header length mismatch %d != %d", ErrMalformedSlice, headerLength, ec.HeaderLength())
+	}
+	return headerLength, nil
+}

object/object.go

@@ -366,6 +366,14 @@ func (o *Object) Children() []oid.ID {
 	return res
 }
 
+func (o *Object) GetECHeader() *ECHeader {
+	v2 := (*object.Object)(o).GetHeader().GetEC()
+
+	var ec ECHeader
+	_ = ec.ReadFromV2(v2) // Errors is checked on unmarshal.
+	return &ec
+}
+
 // SetChildren sets list of the identifiers of the child objects.
 func (o *Object) SetChildren(v ...oid.ID) {
 	var (