diff options
Diffstat (limited to 'vendor/github.com/syndtr/goleveldb/leveldb/iterator/array_iter.go')
-rw-r--r-- | vendor/github.com/syndtr/goleveldb/leveldb/iterator/array_iter.go | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/iterator/array_iter.go b/vendor/github.com/syndtr/goleveldb/leveldb/iterator/array_iter.go new file mode 100644 index 000000000..a23ab05f7 --- /dev/null +++ b/vendor/github.com/syndtr/goleveldb/leveldb/iterator/array_iter.go @@ -0,0 +1,184 @@ +// Copyright (c) 2014, Suryandaru Triandana <syndtr@gmail.com> +// All rights reserved. +// +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +package iterator + +import ( + "github.com/syndtr/goleveldb/leveldb/util" +) + +// BasicArray is the interface that wraps basic Len and Search method. +type BasicArray interface { + // Len returns length of the array. + Len() int + + // Search finds smallest index that point to a key that is greater + // than or equal to the given key. + Search(key []byte) int +} + +// Array is the interface that wraps BasicArray and basic Index method. +type Array interface { + BasicArray + + // Index returns key/value pair with index of i. + Index(i int) (key, value []byte) +} + +// Array is the interface that wraps BasicArray and basic Get method. +type ArrayIndexer interface { + BasicArray + + // Get returns a new data iterator with index of i. + Get(i int) Iterator +} + +type basicArrayIterator struct { + util.BasicReleaser + array BasicArray + pos int + err error +} + +func (i *basicArrayIterator) Valid() bool { + return i.pos >= 0 && i.pos < i.array.Len() && !i.Released() +} + +func (i *basicArrayIterator) First() bool { + if i.Released() { + i.err = ErrIterReleased + return false + } + + if i.array.Len() == 0 { + i.pos = -1 + return false + } + i.pos = 0 + return true +} + +func (i *basicArrayIterator) Last() bool { + if i.Released() { + i.err = ErrIterReleased + return false + } + + n := i.array.Len() + if n == 0 { + i.pos = 0 + return false + } + i.pos = n - 1 + return true +} + +func (i *basicArrayIterator) Seek(key []byte) bool { + if i.Released() { + i.err = ErrIterReleased + return false + } + + n := i.array.Len() + if n == 0 { + i.pos = 0 + return false + } + i.pos = i.array.Search(key) + if i.pos >= n { + return false + } + return true +} + +func (i *basicArrayIterator) Next() bool { + if i.Released() { + i.err = ErrIterReleased + return false + } + + i.pos++ + if n := i.array.Len(); i.pos >= n { + i.pos = n + return false + } + return true +} + +func (i *basicArrayIterator) Prev() bool { + if i.Released() { + i.err = ErrIterReleased + return false + } + + i.pos-- + if i.pos < 0 { + i.pos = -1 + return false + } + return true +} + +func (i *basicArrayIterator) Error() error { return i.err } + +type arrayIterator struct { + basicArrayIterator + array Array + pos int + key, value []byte +} + +func (i *arrayIterator) updateKV() { + if i.pos == i.basicArrayIterator.pos { + return + } + i.pos = i.basicArrayIterator.pos + if i.Valid() { + i.key, i.value = i.array.Index(i.pos) + } else { + i.key = nil + i.value = nil + } +} + +func (i *arrayIterator) Key() []byte { + i.updateKV() + return i.key +} + +func (i *arrayIterator) Value() []byte { + i.updateKV() + return i.value +} + +type arrayIteratorIndexer struct { + basicArrayIterator + array ArrayIndexer +} + +func (i *arrayIteratorIndexer) Get() Iterator { + if i.Valid() { + return i.array.Get(i.basicArrayIterator.pos) + } + return nil +} + +// NewArrayIterator returns an iterator from the given array. +func NewArrayIterator(array Array) Iterator { + return &arrayIterator{ + basicArrayIterator: basicArrayIterator{array: array, pos: -1}, + array: array, + pos: -1, + } +} + +// NewArrayIndexer returns an index iterator from the given array. +func NewArrayIndexer(array ArrayIndexer) IteratorIndexer { + return &arrayIteratorIndexer{ + basicArrayIterator: basicArrayIterator{array: array, pos: -1}, + array: array, + } +} |