array lazy fill and full fill

feature_any_array.go

@@ -0,0 +1,127 @@
+package jsoniter
+
+type arrayLazyAny struct {
+	baseAny
+	buf       []byte
+	iter      *Iterator
+	err       error
+	cache     []Any
+	remaining []byte
+}
+
+func (any *arrayLazyAny) parse() *Iterator {
+	iter := any.iter
+	if iter == nil {
+		iter = NewIterator()
+		any.iter = iter
+	}
+	iter.ResetBytes(any.remaining)
+	return iter
+}
+
+func (any *arrayLazyAny) fillCacheUntil(target int) Any {
+	if any.remaining == nil {
+		if target >= len(any.cache) {
+			return nil
+		}
+		return any.cache[target]
+	}
+	i := len(any.cache)
+	if target < i {
+		return any.cache[target]
+	}
+	iter := any.parse()
+	if (len(any.remaining) == len(any.buf)) {
+		iter.head++
+		c := iter.nextToken()
+		if c != ']' {
+			iter.unreadByte()
+			element := iter.readAny(iter)
+			any.cache = append(any.cache, element)
+			if target == 0 {
+				any.remaining = iter.buf[iter.head:]
+				return element
+			}
+			i = 1
+		} else {
+			any.remaining = nil
+			return nil
+		}
+	}
+	for iter.nextToken() == ',' {
+		element := iter.readAny(iter)
+		any.cache = append(any.cache, element)
+		if i == target {
+			any.remaining = iter.buf[iter.head:]
+			return element
+		}
+		i++
+ 	}
+	any.remaining = nil
+	return nil
+}
+
+func (any *arrayLazyAny) fillCache() {
+	if any.remaining == nil {
+		return
+	}
+	iter := any.parse()
+	if len(any.remaining) == len(any.buf) {
+		iter.head++
+		c := iter.nextToken()
+		if c != ']' {
+			iter.unreadByte()
+			any.cache = append(any.cache, iter.readAny(iter))
+		} else {
+			any.remaining = nil
+			return
+		}
+	}
+	for iter.nextToken() == ',' {
+		any.cache = append(any.cache, iter.readAny(iter))
+	}
+	any.remaining = nil
+	return
+}
+
+func (any *arrayLazyAny) LastError() error {
+	return nil
+}
+
+func (any *arrayLazyAny) ToBool() bool {
+	return false
+}
+
+func (any *arrayLazyAny) ToInt() int {
+	return 0
+}
+
+func (any *arrayLazyAny) ToInt32() int32 {
+	return 0
+}
+
+func (any *arrayLazyAny) ToInt64() int64 {
+	return 0
+}
+
+func (any *arrayLazyAny) ToFloat32() float32 {
+	return 0
+}
+
+func (any *arrayLazyAny) ToFloat64() float64 {
+	return 0
+}
+
+func (any *arrayLazyAny) ToString() string {
+	return ""
+}
+
+func (any *arrayLazyAny) Get(path ...interface{}) Any {
+	idx := path[0].(int)
+	return any.fillCacheUntil(idx)
+}
+
+func (any *arrayLazyAny) Size() int {
+	any.fillCache()
+	return len(any.cache)
+}