1 files changed, 227 insertions, 0 deletions
diff --git a/vendor/github.com/couchbase/vellum/encoder_v1.go b/vendor/github.com/couchbase/vellum/encoder_v1.go
new file mode 100644
index 0000000000..0651fc8614
--- /dev/null
+++ b/vendor/github.com/couchbase/vellum/encoder_v1.go
@@ -0,0 +1,227 @@
+//  Copyright (c) 2017 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package vellum
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+const versionV1 = 1
+const oneTransition = 1 << 7
+const transitionNext = 1 << 6
+const stateFinal = 1 << 6
+const footerSizeV1 = 16
+
+func init() {
+	registerEncoder(versionV1, func(w io.Writer) encoder {
+		return newEncoderV1(w)
+	})
+}
+
+type encoderV1 struct {
+	bw *writer
+}
+
+func newEncoderV1(w io.Writer) *encoderV1 {
+	return &encoderV1{
+		bw: newWriter(w),
+	}
+}
+
+func (e *encoderV1) reset(w io.Writer) {
+	e.bw.Reset(w)
+}
+
+func (e *encoderV1) start() error {
+	header := make([]byte, headerSize)
+	binary.LittleEndian.PutUint64(header, versionV1)
+	binary.LittleEndian.PutUint64(header[8:], uint64(0)) // type
+	n, err := e.bw.Write(header)
+	if err != nil {
+		return err
+	}
+	if n != headerSize {
+		return fmt.Errorf("short write of header %d/%d", n, headerSize)
+	}
+	return nil
+}
+
+func (e *encoderV1) encodeState(s *builderNode, lastAddr int) (int, error) {
+	if len(s.trans) == 0 && s.final && s.finalOutput == 0 {
+		return 0, nil
+	} else if len(s.trans) != 1 || s.final {
+		return e.encodeStateMany(s)
+	} else if !s.final && s.trans[0].out == 0 && s.trans[0].addr == lastAddr {
+		return e.encodeStateOneFinish(s, transitionNext)
+	}
+	return e.encodeStateOne(s)
+}
+
+func (e *encoderV1) encodeStateOne(s *builderNode) (int, error) {
+	start := uint64(e.bw.counter)
+	outPackSize := 0
+	if s.trans[0].out != 0 {
+		outPackSize = packedSize(s.trans[0].out)
+		err := e.bw.WritePackedUintIn(s.trans[0].out, outPackSize)
+		if err != nil {
+			return 0, err
+		}
+	}
+	delta := deltaAddr(start, uint64(s.trans[0].addr))
+	transPackSize := packedSize(delta)
+	err := e.bw.WritePackedUintIn(delta, transPackSize)
+	if err != nil {
+		return 0, err
+	}
+
+	packSize := encodePackSize(transPackSize, outPackSize)
+	err = e.bw.WriteByte(packSize)
+	if err != nil {
+		return 0, err
+	}
+
+	return e.encodeStateOneFinish(s, 0)
+}
+
+func (e *encoderV1) encodeStateOneFinish(s *builderNode, next byte) (int, error) {
+	enc := encodeCommon(s.trans[0].in)
+
+	// not a common input
+	if enc == 0 {
+		err := e.bw.WriteByte(s.trans[0].in)
+		if err != nil {
+			return 0, err
+		}
+	}
+	err := e.bw.WriteByte(oneTransition | next | enc)
+	if err != nil {
+		return 0, err
+	}
+
+	return e.bw.counter - 1, nil
+}
+
+func (e *encoderV1) encodeStateMany(s *builderNode) (int, error) {
+	start := uint64(e.bw.counter)
+	transPackSize := 0
+	outPackSize := packedSize(s.finalOutput)
+	anyOutputs := s.finalOutput != 0
+	for i := range s.trans {
+		delta := deltaAddr(start, uint64(s.trans[i].addr))
+		tsize := packedSize(delta)
+		if tsize > transPackSize {
+			transPackSize = tsize
+		}
+		osize := packedSize(s.trans[i].out)
+		if osize > outPackSize {
+			outPackSize = osize
+		}
+		anyOutputs = anyOutputs || s.trans[i].out != 0
+	}
+	if !anyOutputs {
+		outPackSize = 0
+	}
+
+	if anyOutputs {
+		// output final value
+		if s.final {
+			err := e.bw.WritePackedUintIn(s.finalOutput, outPackSize)
+			if err != nil {
+				return 0, err
+			}
+		}
+		// output transition values (in reverse)
+		for j := len(s.trans) - 1; j >= 0; j-- {
+			err := e.bw.WritePackedUintIn(s.trans[j].out, outPackSize)
+			if err != nil {
+				return 0, err
+			}
+		}
+	}
+
+	// output transition dests (in reverse)
+	for j := len(s.trans) - 1; j >= 0; j-- {
+		delta := deltaAddr(start, uint64(s.trans[j].addr))
+		err := e.bw.WritePackedUintIn(delta, transPackSize)
+		if err != nil {
+			return 0, err
+		}
+	}
+
+	// output transition keys (in reverse)
+	for j := len(s.trans) - 1; j >= 0; j-- {
+		err := e.bw.WriteByte(s.trans[j].in)
+		if err != nil {
+			return 0, err
+		}
+	}
+
+	packSize := encodePackSize(transPackSize, outPackSize)
+	err := e.bw.WriteByte(packSize)
+	if err != nil {
+		return 0, err
+	}
+
+	numTrans := encodeNumTrans(len(s.trans))
+
+	// if number of transitions wont fit in edge header byte
+	// write out separately
+	if numTrans == 0 {
+		if len(s.trans) == 256 {
+			// this wouldn't fit in single byte, but reuse value 1
+			// which would have always fit in the edge header instead
+			err = e.bw.WriteByte(1)
+			if err != nil {
+				return 0, err
+			}
+		} else {
+			err = e.bw.WriteByte(byte(len(s.trans)))
+			if err != nil {
+				return 0, err
+			}
+		}
+	}
+
+	// finally write edge header
+	if s.final {
+		numTrans |= stateFinal
+	}
+	err = e.bw.WriteByte(numTrans)
+	if err != nil {
+		return 0, err
+	}
+
+	return e.bw.counter - 1, nil
+}
+
+func (e *encoderV1) finish(count, rootAddr int) error {
+	footer := make([]byte, footerSizeV1)
+	binary.LittleEndian.PutUint64(footer, uint64(count))        // root addr
+	binary.LittleEndian.PutUint64(footer[8:], uint64(rootAddr)) // root addr
+	n, err := e.bw.Write(footer)
+	if err != nil {
+		return err
+	}
+	if n != footerSizeV1 {
+		return fmt.Errorf("short write of footer %d/%d", n, footerSizeV1)
+	}
+	err = e.bw.Flush()
+	if err != nil {
+		return err
+	}
+	return nil
+}