util

Documentation

Overview

Package util provides generic utilities used throughout the policy engine.

Index

• func BFS(t Traversal, f Iter, u T) bool
• func Compare(a, b interface{}) int
• func DFS(t Traversal, f Iter, u T) bool
• func MustMarshalJSON(x interface{}) []byte
• func MustUnmarshalJSON(bs []byte) interface{}
• func NewJSONDecoder(r io.Reader) *json.Decoder
• func UnmarshalJSON(bs []byte, x interface{}) (err error)
• type EnumFlag
  • func NewEnumFlag(defaultValue string, vs []string) *EnumFlag
  • func (f *EnumFlag) Set(s string) error
  • func (f *EnumFlag) String() string
  • func (f *EnumFlag) Type() string
• type Equals
• type FIFO
  • func NewFIFO(ts ...T) *FIFO
  • func (s *FIFO) Peek() (T, bool)
  • func (s *FIFO) Pop() (T, bool)
  • func (s *FIFO) Push(t T)
  • func (s *FIFO) Size() int
• type HashMap
  • func NewHashMap(eq func(T, T) bool, hash func(T) int) *HashMap
  • func (h *HashMap) Copy() *HashMap
  • func (h *HashMap) Delete(k T)
  • func (h *HashMap) Equal(other *HashMap) bool
  • func (h *HashMap) Get(k T) (T, bool)
  • func (h *HashMap) Hash() int
  • func (h *HashMap) Iter(iter func(T, T) bool) bool
  • func (h *HashMap) Len() int
  • func (h *HashMap) Put(k T, v T)
  • func (h *HashMap) String() string
  • func (h *HashMap) Update(other *HashMap) *HashMap
• type Iter
• type LIFO
  • func NewLIFO(ts ...T) *LIFO
  • func (s *LIFO) Peek() (T, bool)
  • func (s *LIFO) Pop() (T, bool)
  • func (s *LIFO) Push(t T)
  • func (s *LIFO) Size() int
• type T
  • func DFSPath(t Traversal, eq Equals, a, z T) []T
• type Traversal

Functions

func BFS

func BFS(t Traversal, f Iter, u T) bool

BFS performs a breadth first traversal calling f for each node starting from u. If f returns true, traversal stops and BFS returns true.

func Compare

func Compare(a, b interface{}) int

Compare returns 0 if a equals b, -1 if a is less than b, and 1 if b is than a.

For comparison between values of different types, the following ordering is used: nil < bool < float64 < string < []interface{} < map[string]interface{}. Slices and maps are compared recursively. If one slice or map is a subset of the other slice or map it is considered "less than". Nil is always equal to nil.

func DFS

func DFS(t Traversal, f Iter, u T) bool

DFS performs a depth first traversal calling f for each node starting from u. If f returns true, traversal stops and DFS returns true.

func MustMarshalJSON

func MustMarshalJSON(x interface{}) []byte

MustMarshalJSON returns the JSON encoding of x

If the data cannot be encoded, this function will panic. This function is for test purposes.

func MustUnmarshalJSON

func MustUnmarshalJSON(bs []byte) interface{}

MustUnmarshalJSON parse the JSON encoded data and returns the result.

If the data cannot be decoded, this function will panic. This function is for test purposes.

func NewJSONDecoder

func NewJSONDecoder(r io.Reader) *json.Decoder

NewJSONDecoder returns a new decoder that reads from r.

This function is intended to be used in place of the standard json.NewDecoder when json.Number is required.

func UnmarshalJSON

func UnmarshalJSON(bs []byte, x interface{}) (err error)

UnmarshalJSON parses the JSON encoded data and stores the result in the value pointed to by x.

This function is intended to be used in place of the standard json.Marshal function when json.Number is required.

Types

type EnumFlag

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

EnumFlag implements the pflag.Value interface to provide enumerated command line parameter values.

func NewEnumFlag

func NewEnumFlag(defaultValue string, vs []string) *EnumFlag

NewEnumFlag returns a new EnumFlag that has a defaultValue and vs enumerated values.

func (*EnumFlag) Set

func (f *EnumFlag) Set(s string) error

Set sets the enum value. If s is not a valid enum value, an error is returned.

func (*EnumFlag) String

func (f *EnumFlag) String() string

String returns the EnumValue's value as string.

func (*EnumFlag) Type

func (f *EnumFlag) Type() string

Type returns the valid enumeration values.

type Equals

type Equals func(u T, v T) bool

Equals should return true if node "u" equals node "v".

type FIFO

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

FIFO represents a simple FIFO queue.

func NewFIFO

func NewFIFO(ts ...T) *FIFO

NewFIFO returns a new FIFO queue containing elements ts starting with the left-most argument at the front.

func (*FIFO) Peek

func (s *FIFO) Peek() (T, bool)

Peek returns the top of the LIFO. If LIFO is empty, returns nil, false.

func (*FIFO) Pop

func (s *FIFO) Pop() (T, bool)

Pop returns the top of the LIFO and removes it. If LIFO is empty returns nil, false.

func (*FIFO) Push

func (s *FIFO) Push(t T)

Push adds a new element onto the LIFO.

func (*FIFO) Size

func (s *FIFO) Size() int

Size returns the size of the LIFO.

type HashMap

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

HashMap represents a key/value map.

func NewHashMap

func NewHashMap(eq func(T, T) bool, hash func(T) int) *HashMap

NewHashMap returns a new empty HashMap.

func (*HashMap) Copy

func (h *HashMap) Copy() *HashMap

Copy returns a shallow copy of this HashMap.

func (*HashMap) Delete

func (h *HashMap) Delete(k T)

Delete removes the the key k.

func (*HashMap) Equal

func (h *HashMap) Equal(other *HashMap) bool

Equal returns true if this HashMap equals the other HashMap. Two hash maps are equal if they contain the same key/value pairs.

func (*HashMap) Get

func (h *HashMap) Get(k T) (T, bool)

Get returns the value for k.

func (*HashMap) Hash

func (h *HashMap) Hash() int

Hash returns the hash code for this hash map.

func (*HashMap) Iter

func (h *HashMap) Iter(iter func(T, T) bool) bool

Iter invokes the iter function for each element in the HashMap. If the iter function returns true, iteration stops and the return value is true. If the iter function never returns true, iteration proceeds through all elements and the return value is false.

func (*HashMap) Len

func (h *HashMap) Len() int

Len returns the current size of this HashMap.

func (*HashMap) Put

func (h *HashMap) Put(k T, v T)

Put inserts a key/value pair into this HashMap. If the key is already present, the existing value is overwritten.

func (*HashMap) String

func (h *HashMap) String() string

func (*HashMap) Update

func (h *HashMap) Update(other *HashMap) *HashMap

Update returns a new HashMap with elements from the other HashMap put into this HashMap. If the other HashMap contains elements with the same key as this HashMap, the value from the other HashMap overwrites the value from this HashMap.

type Iter

type Iter func(u T) bool

Iter should return true to indicate stop.

type LIFO

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

LIFO represents a simple LIFO queue.

func NewLIFO

func NewLIFO(ts ...T) *LIFO

NewLIFO returns a new LIFO queue containing elements ts starting with the left-most argument at the bottom.

func (*LIFO) Peek

func (s *LIFO) Peek() (T, bool)

Peek returns the top of the LIFO. If LIFO is empty, returns nil, false.

func (*LIFO) Pop

func (s *LIFO) Pop() (T, bool)

Pop returns the top of the LIFO and removes it. If LIFO is empty returns nil, false.

func (*LIFO) Push

func (s *LIFO) Push(t T)

Push adds a new element onto the LIFO.

func (*LIFO) Size

func (s *LIFO) Size() int

Size returns the size of the LIFO.

type T

type T interface{}

T is a concise way to refer to T.

func DFSPath

func DFSPath(t Traversal, eq Equals, a, z T) []T

DFSPath returns a path from node a to node z found by performing a depth first traversal. If no path is found, an empty slice is returned.

type Traversal

type Traversal interface {

	// Edges should return the neighbours of node "u".
	Edges(u T) []T

	// Visited should return true if node "u" has already been visited in this
	// traversal. If the same traversal is used multiple times, the state that
	// tracks visited nodes should be reset.
	Visited(u T) bool
}

Traversal defines a basic interface to perform traversals.