stream/mts: added meta.go file to contain struct and methods relating to Metadata and operations

stream/mts/encoder.go

@@ -29,10 +29,7 @@ LICENSE
 package mts
 
 import (
-	"errors"
-	"fmt"
 	"io"
-	"sync"
 	"time"
 
 	"bitbucket.org/ausocean/av/stream/mts/pes"
@@ -93,49 +90,6 @@ const (
 // global Meta
 var meta Meta
 
-type Meta struct {
-	mu   sync.RWMutex
-	data map[string]string
-}
-
-// Add adds metadata with key and val, if already exists return error
-func (m *Meta) Add(key, val string) error {
-	m.mu.Lock()
-	if _, exists := m.data[key]; !exists {
-		return errors.New(fmt.Sprintf("Metadata for: %v already exists", key))
-	}
-	m.data[key] = val
-	m.mu.Unlock()
-	return nil
-}
-
-// All returns the a copy of the map containing the meta data
-func (m *Meta) All() map[string]string {
-	var cpy map[string]string
-	for k, v := range m.data {
-		cpy[k] = v
-	}
-	return cpy
-}
-
-// Get returns the meta data for the passed key
-func (m *Meta) Get(key string) (string, error) {
-	val, ok := m.data[key]
-	if !ok {
-		return "", errors.New("Key does not exist in metadata map")
-	}
-	return val, nil
-}
-
-// Remove deletes a meta entry in the map and returns error if it doesn’t exist
-func (m *Meta) Delete(key string) error {
-	if _, ok := m.data[key]; ok {
-		delete(m.data, key)
-		return nil
-	}
-	return errors.New("Trying to delete map entry that doesn't exist")
-}
-
 // updateMeta ...
 func updateMeta(b []byte) error {
 	var p psi.PSIBytes