From 8ec4ef32d026f1b6b043b3268eccf68293266014 Mon Sep 17 00:00:00 2001
From: Meng-Ying Yang <garfield@dexon.org>
Date: Mon, 15 Apr 2019 11:14:31 +0800
Subject: core: vm: sqlvm: add opFunc

Add `opFunc` as built-in funtions entry point.
---
 core/vm/sqlvm/errors/errors.go             |  2 ++
 core/vm/sqlvm/runtime/functions.go         | 11 +++++++++
 core/vm/sqlvm/runtime/instructions.go      | 36 ++++++++++++++++++++++++++++++
 core/vm/sqlvm/runtime/instructions_test.go |  4 ++--
 core/vm/sqlvm/runtime/jumptable.go         |  3 +++
 core/vm/sqlvm/runtime/opcodes.go           |  5 +++++
 6 files changed, 59 insertions(+), 2 deletions(-)
 create mode 100644 core/vm/sqlvm/runtime/functions.go

diff --git a/core/vm/sqlvm/errors/errors.go b/core/vm/sqlvm/errors/errors.go
index b6c3909af..e69993300 100644
--- a/core/vm/sqlvm/errors/errors.go
+++ b/core/vm/sqlvm/errors/errors.go
@@ -123,6 +123,7 @@ const (
 	ErrorCodeDataLengthNotMatch
 	ErrorCodeMultipleEscapeByte
 	ErrorCodePendingEscapeByte
+	ErrorCodeNoSuchFunction
 )
 
 var errorCodeMap = [...]string{
@@ -157,6 +158,7 @@ var errorCodeMap = [...]string{
 	ErrorCodeDataLengthNotMatch: "data length not match",
 	ErrorCodeMultipleEscapeByte: "multiple escape byte",
 	ErrorCodePendingEscapeByte:  "pending escape byte",
+	ErrorCodeNoSuchFunction:     "no such function",
 }
 
 func (c ErrorCode) Error() string {
diff --git a/core/vm/sqlvm/runtime/functions.go b/core/vm/sqlvm/runtime/functions.go
new file mode 100644
index 000000000..798f5a573
--- /dev/null
+++ b/core/vm/sqlvm/runtime/functions.go
@@ -0,0 +1,11 @@
+package runtime
+
+import (
+	"github.com/dexon-foundation/dexon/core/vm/sqlvm/common"
+)
+
+type fn func(*common.Context, []*Operand, uint64) (*Operand, error)
+
+var (
+	fnTable = map[string]fn{}
+)
diff --git a/core/vm/sqlvm/runtime/instructions.go b/core/vm/sqlvm/runtime/instructions.go
index 5cd622180..cd034955a 100644
--- a/core/vm/sqlvm/runtime/instructions.go
+++ b/core/vm/sqlvm/runtime/instructions.go
@@ -1830,3 +1830,39 @@ func (t Tuple) neg(ctx *common.Context, meta []ast.DataType) (t2 Tuple, err erro
 	}
 	return
 }
+
+func opFunc(ctx *common.Context, ops, registers []*Operand, output uint) (err error) {
+	if len(ops) < 2 {
+		err = se.ErrorCodeInvalidOperandNum
+		return
+	}
+
+	var (
+		op, funcID = ops[0], ops[1]
+		op2        *Operand
+		length     uint64
+	)
+
+	if op.IsImmediate {
+		length, err = ast.DecimalToUint64(op.Data[0][0].Value)
+		if err != nil {
+			return
+		}
+	} else {
+		length = uint64(len(op.Data))
+	}
+
+	fn, ok := fnTable[string(funcID.Data[0][0].Bytes)]
+	if !ok {
+		err = se.ErrorCodeNoSuchFunction
+		return
+	}
+
+	result, err = fnTable[id](ctx, ops[2:], length)
+	if err != nil {
+		return
+	}
+
+	registers[output] = op2
+	return
+}
diff --git a/core/vm/sqlvm/runtime/instructions_test.go b/core/vm/sqlvm/runtime/instructions_test.go
index c071045e6..a399ad557 100644
--- a/core/vm/sqlvm/runtime/instructions_test.go
+++ b/core/vm/sqlvm/runtime/instructions_test.go
@@ -210,7 +210,7 @@ type opLoadTestCase struct {
 
 func (s *opLoadSuite) SetupTest() {
 	s.ctx = &common.Context{}
-	s.ctx.Storage = s.newStorage()
+	s.ctx.Storage = newStorage()
 	targetTableRef := schema.TableRef(1)
 	s.headHash = s.ctx.Storage.GetRowPathHash(targetTableRef, uint64(123456))
 	s.address = dexCommon.HexToAddress("0x6655")
@@ -374,7 +374,7 @@ func newFieldsOperand(fields []uint8) *Operand {
 	return o
 }
 
-func (s *opLoadSuite) newStorage() *common.Storage {
+func newStorage() *common.Storage {
 	db := ethdb.NewMemDatabase()
 	state, _ := state.New(dexCommon.Hash{}, state.NewDatabase(db))
 	storage := common.NewStorage(state)
diff --git a/core/vm/sqlvm/runtime/jumptable.go b/core/vm/sqlvm/runtime/jumptable.go
index ef1fc8841..2930520a1 100644
--- a/core/vm/sqlvm/runtime/jumptable.go
+++ b/core/vm/sqlvm/runtime/jumptable.go
@@ -31,6 +31,9 @@ var jumpTable = [256]OpFunction{
 	CUT:    opCut,
 	RANGE:  opRange,
 
+	// 0x50
+	FUNC: opFunc,
+
 	// 0x60
 	LOAD: opLoad,
 }
diff --git a/core/vm/sqlvm/runtime/opcodes.go b/core/vm/sqlvm/runtime/opcodes.go
index 5a0e5dd95..e65565670 100644
--- a/core/vm/sqlvm/runtime/opcodes.go
+++ b/core/vm/sqlvm/runtime/opcodes.go
@@ -51,6 +51,11 @@ const (
 	RANGE
 )
 
+// 0x50 range - function ops
+const (
+	FUNC = iota + 0x50
+)
+
 // 0x60 range - storage ops
 const (
 	INSERT = iota + 0x60
-- 
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