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README

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Common data structures for golang

References

• https://github.com/beeker1121/goque

Documentation

Index

• Variables
• type CompareFunc
• type Item
  • func (i *Item) ToObject(value interface{}) error
  • func (i *Item) ToString() string
• type PriorityItem
• type PriorityQueue
  • func OpenPriorityQueue(dataDir string) (*PriorityQueue, error)
  • func (pq *PriorityQueue) Close() error
  • func (pq *PriorityQueue) Dequeue() (*PriorityItem, error)
  • func (pq *PriorityQueue) Drop() error
  • func (pq *PriorityQueue) EnqueueObject(value interface{}, priority uint8) (*PriorityItem, error)
  • func (pq *PriorityQueue) EnqueueString(value string, priority uint8) (*PriorityItem, error)
  • func (pq *PriorityQueue) EnqueueWithPriority(value []byte, priority uint8) (*PriorityItem, error)
  • func (pq *PriorityQueue) Length() uint64
  • func (pq *PriorityQueue) Peek() (*PriorityItem, error)
• type Queue
  • func OpenQueue(dataDir string) (*Queue, error)
  • func (q *Queue) Close() error
  • func (q *Queue) Dequeue() (*Item, error)
  • func (q *Queue) Drop() error
  • func (q *Queue) Enqueue(value []byte) (*Item, error)
  • func (q *Queue) EnqueueObject(value interface{}) (*Item, error)
  • func (q *Queue) EnqueueString(value string) (*Item, error)
  • func (q *Queue) Length() uint64
  • func (q *Queue) Peek() (*Item, error)
• type SortedList
  • func NewSortedList(compare CompareFunc) *SortedList
  • func (l *SortedList) Back() *list.Element
  • func (l *SortedList) Clear()
  • func (l *SortedList) Front() *list.Element
  • func (l *SortedList) Insert(item interface{})
  • func (l *SortedList) Len() int64
  • func (l *SortedList) Remove(e *list.Element) interface{}
• type Stack
  • func OpenStack(dataDir string) (*Stack, error)
  • func (s *Stack) Close() error
  • func (s *Stack) Drop() error
  • func (s *Stack) Length() uint64
  • func (s *Stack) Peek() (*Item, error)
  • func (s *Stack) PeekByID(id uint64) (*Item, error)
  • func (s *Stack) PeekByOffset(offset uint64) (*Item, error)
  • func (s *Stack) Pop() (*Item, error)
  • func (s *Stack) Push(value []byte) (*Item, error)
  • func (s *Stack) PushObject(value interface{}) (*Item, error)
  • func (s *Stack) PushString(value string) (*Item, error)
  • func (s *Stack) Update(id uint64, newValue []byte) (*Item, error)
  • func (s *Stack) UpdateObject(id uint64, newValue interface{}) (*Item, error)
  • func (s *Stack) UpdateString(id uint64, newValue string) (*Item, error)

Variables

var (
	ErrDBClosed    = errors.New("queue: database is closed")
	ErrEmpty       = errors.New("queue: queue is empty")
	ErrOutOfBounds = errors.New("queue: ID is outside range of queue")
)

Types

type CompareFunc

type CompareFunc func(interface{}, interface{}) int

type Item

type Item struct {
	ID    uint64
	Key   []byte
	Value []byte
}

func (*Item) ToObject

func (i *Item) ToObject(value interface{}) error

func (*Item) ToString

func (i *Item) ToString() string

type PriorityItem

type PriorityItem struct {
	Item
	Priority uint8
}

PriorityItem extends Item with a priority field

type PriorityQueue

type PriorityQueue struct {
	DataDir string

	sync.RWMutex
	// contains filtered or unexported fields
}

PriorityQueue implements a priority queue using leveldb

func OpenPriorityQueue

func OpenPriorityQueue(dataDir string) (*PriorityQueue, error)

OpenPriorityQueue creates or opens a priority queue

func (*PriorityQueue) Close

func (pq *PriorityQueue) Close() error

Close closes the priority queue database

func (*PriorityQueue) Dequeue

func (pq *PriorityQueue) Dequeue() (*PriorityItem, error)

Dequeue removes and returns the highest priority item

func (*PriorityQueue) Drop

func (pq *PriorityQueue) Drop() error

Drop closes and deletes the priority queue database

func (*PriorityQueue) EnqueueObject

func (pq *PriorityQueue) EnqueueObject(value interface{}, priority uint8) (*PriorityItem, error)

func (*PriorityQueue) EnqueueString

func (pq *PriorityQueue) EnqueueString(value string, priority uint8) (*PriorityItem, error)

func (*PriorityQueue) EnqueueWithPriority

func (pq *PriorityQueue) EnqueueWithPriority(value []byte, priority uint8) (*PriorityItem, error)

EnqueueWithPriority adds an item to the queue with specified priority

func (*PriorityQueue) Length

func (pq *PriorityQueue) Length() uint64

Length returns the number of items in the queue

func (*PriorityQueue) Peek

func (pq *PriorityQueue) Peek() (*PriorityItem, error)

Peek returns the highest priority item without removing it

type Queue

type Queue struct {
	sync.RWMutex
	DataDir string
	// contains filtered or unexported fields
}

Standard FIFO (fist in, first out) queue

func OpenQueue

func OpenQueue(dataDir string) (*Queue, error)

func (*Queue) Close

func (q *Queue) Close() error

func (*Queue) Dequeue

func (q *Queue) Dequeue() (*Item, error)

func (*Queue) Drop

func (q *Queue) Drop() error

func (*Queue) Enqueue

func (q *Queue) Enqueue(value []byte) (*Item, error)

func (*Queue) EnqueueObject

func (q *Queue) EnqueueObject(value interface{}) (*Item, error)

func (*Queue) EnqueueString

func (q *Queue) EnqueueString(value string) (*Item, error)

func (*Queue) Length

func (q *Queue) Length() uint64

func (*Queue) Peek

func (q *Queue) Peek() (*Item, error)

type SortedList

type SortedList struct {
	// contains filtered or unexported fields
}

func NewSortedList

func NewSortedList(compare CompareFunc) *SortedList

func (*SortedList) Back

func (l *SortedList) Back() *list.Element

func (*SortedList) Clear

func (l *SortedList) Clear()

func (*SortedList) Front

func (l *SortedList) Front() *list.Element

func (*SortedList) Insert

func (l *SortedList) Insert(item interface{})

Only Search from front to end, optimized for from end to front

func (*SortedList) Len

func (l *SortedList) Len() int64

func (*SortedList) Remove

func (l *SortedList) Remove(e *list.Element) interface{}

type Stack

type Stack struct {
	sync.RWMutex
	DataDir string
	// contains filtered or unexported fields
}

Stack is a standard LIFO (last in, first out) stack.

func OpenStack

func OpenStack(dataDir string) (*Stack, error)

OpenStack opens a stack if one exists at the given directory. If one does not already exist, a new stack is created.

func (*Stack) Close

func (s *Stack) Close() error

Close closes the LevelDB database of the stack.

func (*Stack) Drop

func (s *Stack) Drop() error

Drop closes and deletes the LevelDB database of the stack.

func (*Stack) Length

func (s *Stack) Length() uint64

Length returns the total number of items in the stack.

func (*Stack) Peek

func (s *Stack) Peek() (*Item, error)

Peek returns the next item in the stack without removing it.

func (*Stack) PeekByID

func (s *Stack) PeekByID(id uint64) (*Item, error)

PeekByID returns the item with the given ID without removing it.

func (*Stack) PeekByOffset

func (s *Stack) PeekByOffset(offset uint64) (*Item, error)

PeekByOffset returns the item located at the given offset, starting from the head of the stack, without removing it.

func (*Stack) Pop

func (s *Stack) Pop() (*Item, error)

Pop removes the next item in the stack and returns it.

func (*Stack) Push

func (s *Stack) Push(value []byte) (*Item, error)

Push adds an item to the stack.

func (*Stack) PushObject

func (s *Stack) PushObject(value interface{}) (*Item, error)

PushObject is a helper function for Push that accepts any value type, which is then encoded into a byte slice using encoding/gob.

func (*Stack) PushString

func (s *Stack) PushString(value string) (*Item, error)

PushString is a helper function for Push that accepts a value as a string rather than a byte slice.

func (*Stack) Update

func (s *Stack) Update(id uint64, newValue []byte) (*Item, error)

Update updates an item in the stack without changing its position.

func (*Stack) UpdateObject

func (s *Stack) UpdateObject(id uint64, newValue interface{}) (*Item, error)

UpdateObject is a helper function for Update that accepts any value type, which is then encoded into a byte slice using encoding/gob.

func (*Stack) UpdateString

func (s *Stack) UpdateString(id uint64, newValue string) (*Item, error)

UpdateString is a helper function for Update that accepts a value as a string rather than a byte slice.