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114 lines
2.9 KiB
114 lines
2.9 KiB
//
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// DISCLAIMER
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//
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// Copyright 2017 ArangoDB GmbH, Cologne, Germany
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// Copyright holder is ArangoDB GmbH, Cologne, Germany
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//
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// Author Ewout Prangsma
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//
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package velocypack
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type ObjectIterator struct {
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s Slice
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position ValueLength
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size ValueLength
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current Slice
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}
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// NewObjectIterator initializes an iterator at position 0 of the given object slice.
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func NewObjectIterator(s Slice, allowRandomIteration ...bool) (*ObjectIterator, error) {
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if !s.IsObject() {
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return nil, InvalidTypeError{"Expected Object slice"}
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}
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size, err := s.Length()
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if err != nil {
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return nil, WithStack(err)
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}
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i := &ObjectIterator{
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s: s,
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position: 0,
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size: size,
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}
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if size > 0 {
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if h := s.head(); h == 0x14 {
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i.current, err = s.KeyAt(0, false)
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} else if optionalBool(allowRandomIteration, false) {
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i.current = s[s.findDataOffset(h):]
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}
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}
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return i, nil
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}
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// IsValid returns true if the given position of the iterator is valid.
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func (i *ObjectIterator) IsValid() bool {
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return i.position < i.size
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}
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// IsFirst returns true if the current position is 0.
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func (i *ObjectIterator) IsFirst() bool {
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return i.position == 0
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}
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// Key returns the key of the current position of the iterator
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func (i *ObjectIterator) Key(translate bool) (Slice, error) {
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if i.position >= i.size {
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return nil, WithStack(IndexOutOfBoundsError)
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}
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if current := i.current; current != nil {
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if translate {
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key, err := current.makeKey()
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return key, WithStack(err)
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}
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return current, nil
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}
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key, err := i.s.getNthKey(i.position, translate)
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return key, WithStack(err)
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}
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// Value returns the value of the current position of the iterator
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func (i *ObjectIterator) Value() (Slice, error) {
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if i.position >= i.size {
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return nil, WithStack(IndexOutOfBoundsError)
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}
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if current := i.current; current != nil {
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value, err := current.Next()
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return value, WithStack(err)
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}
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value, err := i.s.getNthValue(i.position)
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return value, WithStack(err)
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}
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// Next moves to the next position.
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func (i *ObjectIterator) Next() error {
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i.position++
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if i.position < i.size && i.current != nil {
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var err error
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// skip over key
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i.current, err = i.current.Next()
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if err != nil {
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return WithStack(err)
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}
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// skip over value
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i.current, err = i.current.Next()
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if err != nil {
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return WithStack(err)
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}
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} else {
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i.current = nil
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}
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return nil
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}
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