strings.go

// this was modified after generation to work with the normal string type, do not regenerate

// Generated by: gen
// TypeWriter: gen
// Directive: +gen on *dm.String

// See http://clipperhouse.github.io/gen for documentation

// Sort implementation is a modification of http://golang.org/pkg/sort/#Sort
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found at http://golang.org/LICENSE.

package rex

import (
	"errors"
)

// Strings is a slice of type string. Use it where you would use []string.
type Strings []string

// All verifies that all elements of Strings return true for the passed func. See: http://clipperhouse.github.io/gen/#All
func (rcv Strings) All(fn func(string) bool) bool {
	for _, v := range rcv {
		if !fn(v) {
			return false
		}
	}
	return true
}

// Any verifies that one or more elements of Strings return true for the passed func. See: http://clipperhouse.github.io/gen/#Any
func (rcv Strings) Any(fn func(string) bool) bool {
	for _, v := range rcv {
		if fn(v) {
			return true
		}
	}
	return false
}

// Count gives the number elements of Strings that return true for the passed func. See: http://clipperhouse.github.io/gen/#Count
func (rcv Strings) Count(fn func(string) bool) (result int) {
	for _, v := range rcv {
		if fn(v) {
			result++
		}
	}
	return
}

// Distinct returns a new Strings slice whose elements are unique. See: http://clipperhouse.github.io/gen/#Distinct
func (rcv Strings) Distinct() (result Strings) {
	appended := make(map[string]bool)
	for _, v := range rcv {
		if !appended[v] {
			result = append(result, v)
			appended[v] = true
		}
	}
	return result
}

// DistinctBy returns a new Strings slice whose elements are unique, where equality is defined by a passed func. See: http://clipperhouse.github.io/gen/#DistinctBy
func (rcv Strings) DistinctBy(equal func(string, string) bool) (result Strings) {
	for _, v := range rcv {
		eq := func(_app string) bool {
			return equal(v, _app)
		}
		if !result.Any(eq) {
			result = append(result, v)
		}
	}
	return result
}

// Each iterates over Strings and executes the passed func against each element. See: http://clipperhouse.github.io/gen/#Each
func (rcv Strings) Each(fn func(string)) {
	for _, v := range rcv {
		fn(v)
	}
}

// First returns the first element that returns true for the passed func. Returns error if no elements return true. See: http://clipperhouse.github.io/gen/#First
func (rcv Strings) First(fn func(string) bool) (result string, err error) {
	for _, v := range rcv {
		if fn(v) {
			result = v
			return
		}
	}
	err = errors.New("no Strings elements return true for passed func")
	return
}

// IsSortedBy reports whether an instance of Strings is sorted, using the pass func to define ‘less’. See: http://clipperhouse.github.io/gen/#SortBy
func (rcv Strings) IsSortedBy(less func(string, string) bool) bool {
	n := len(rcv)
	for i := n - 1; i > 0; i-- {
		if less(rcv[i], rcv[i-1]) {
			return false
		}
	}
	return true
}

// IsSortedDesc reports whether an instance of Strings is sorted in descending order, using the pass func to define ‘less’. See: http://clipperhouse.github.io/gen/#SortBy
func (rcv Strings) IsSortedByDesc(less func(string, string) bool) bool {
	greater := func(a, b string) bool {
		return a != b && !less(a, b)
	}
	return rcv.IsSortedBy(greater)
}

// MaxBy returns an element of Strings containing the maximum value, when compared to other elements using a passed func defining ‘less’. In the case of multiple items being equally maximal, the last such element is returned. Returns error if no elements. See: http://clipperhouse.github.io/gen/#MaxBy
func (rcv Strings) MaxBy(less func(string, string) bool) (result string, err error) {
	l := len(rcv)
	if l == 0 {
		err = errors.New("cannot determine the MaxBy of an empty slice")
		return
	}
	m := 0
	for i := 1; i < l; i++ {
		if rcv[i] != rcv[m] && !less(rcv[i], rcv[m]) {
			m = i
		}
	}
	result = rcv[m]
	return
}

// MinBy returns an element of Strings containing the minimum value, when compared to other elements using a passed func defining ‘less’. In the case of multiple items being equally minimal, the first such element is returned. Returns error if no elements. See: http://clipperhouse.github.io/gen/#MinBy
func (rcv Strings) MinBy(less func(string, string) bool) (result string, err error) {
	l := len(rcv)
	if l == 0 {
		err = errors.New("cannot determine the Min of an empty slice")
		return
	}
	m := 0
	for i := 1; i < l; i++ {
		if less(rcv[i], rcv[m]) {
			m = i
		}
	}
	result = rcv[m]
	return
}

// Single returns exactly one element of Strings that returns true for the passed func. Returns error if no or multiple elements return true. See: http://clipperhouse.github.io/gen/#Single
func (rcv Strings) Single(fn func(string) bool) (result string, err error) {
	var candidate string
	found := false
	for _, v := range rcv {
		if fn(v) {
			if found {
				err = errors.New("multiple Strings elements return true for passed func")
				return
			}
			candidate = v
			found = true
		}
	}
	if found {
		result = candidate
	} else {
		err = errors.New("no Strings elements return true for passed func")
	}
	return
}

// SortBy returns a new ordered Strings slice, determined by a func defining ‘less’. See: http://clipperhouse.github.io/gen/#SortBy
func (rcv Strings) SortBy(less func(string, string) bool) Strings {
	result := make(Strings, len(rcv))
	copy(result, rcv)
	// Switch to heapsort if depth of 2*ceil(lg(n+1)) is reached.
	n := len(result)
	maxDepth := 0
	for i := n; i > 0; i >>= 1 {
		maxDepth++
	}
	maxDepth *= 2
	quickSortStrings(result, less, 0, n, maxDepth)
	return result
}

// SortByDesc returns a new, descending-ordered Strings slice, determined by a func defining ‘less’. See: http://clipperhouse.github.io/gen/#SortBy
func (rcv Strings) SortByDesc(less func(string, string) bool) Strings {
	greater := func(a, b string) bool {
		return a != b && !less(a, b)
	}
	return rcv.SortBy(greater)
}

// Where returns a new Strings slice whose elements return true for func. See: http://clipperhouse.github.io/gen/#Where
func (rcv Strings) Where(fn func(string) bool) (result Strings) {
	for _, v := range rcv {
		if fn(v) {
			result = append(result, v)
		}
	}
	return result
}

// Sort implementation based on http://golang.org/pkg/sort/#Sort, see top of this file

func swapStrings(rcv Strings, a, b int) {
	rcv[a], rcv[b] = rcv[b], rcv[a]
}

// Insertion sort
func insertionSortStrings(rcv Strings, less func(string, string) bool, a, b int) {
	for i := a + 1; i < b; i++ {
		for j := i; j > a && less(rcv[j], rcv[j-1]); j-- {
			swapStrings(rcv, j, j-1)
		}
	}
}

// siftDown implements the heap property on rcv[lo, hi).
// first is an offset into the array where the root of the heap lies.
func siftDownStrings(rcv Strings, less func(string, string) bool, lo, hi, first int) {
	root := lo
	for {
		child := 2*root + 1
		if child >= hi {
			break
		}
		if child+1 < hi && less(rcv[first+child], rcv[first+child+1]) {
			child++
		}
		if !less(rcv[first+root], rcv[first+child]) {
			return
		}
		swapStrings(rcv, first+root, first+child)
		root = child
	}
}

func heapSortStrings(rcv Strings, less func(string, string) bool, a, b int) {
	first := a
	lo := 0
	hi := b - a

	// Build heap with greatest element at top.
	for i := (hi - 1) / 2; i >= 0; i-- {
		siftDownStrings(rcv, less, i, hi, first)
	}

	// Pop elements, largest first, into end of rcv.
	for i := hi - 1; i >= 0; i-- {
		swapStrings(rcv, first, first+i)
		siftDownStrings(rcv, less, lo, i, first)
	}
}

// Quicksort, following Bentley and McIlroy,
// Engineering a Sort Function, SP&E November 1993.

// medianOfThree moves the median of the three values rcv[a], rcv[b], rcv[c] into rcv[a].
func medianOfThreeStrings(rcv Strings, less func(string, string) bool, a, b, c int) {
	m0 := b
	m1 := a
	m2 := c
	// bubble sort on 3 elements
	if less(rcv[m1], rcv[m0]) {
		swapStrings(rcv, m1, m0)
	}
	if less(rcv[m2], rcv[m1]) {
		swapStrings(rcv, m2, m1)
	}
	if less(rcv[m1], rcv[m0]) {
		swapStrings(rcv, m1, m0)
	}
	// now rcv[m0] <= rcv[m1] <= rcv[m2]
}

func swapRangeStrings(rcv Strings, a, b, n int) {
	for i := 0; i < n; i++ {
		swapStrings(rcv, a+i, b+i)
	}
}

func doPivotStrings(rcv Strings, less func(string, string) bool, lo, hi int) (midlo, midhi int) {
	m := lo + (hi-lo)/2 // Written like this to avoid integer overflow.
	if hi-lo > 40 {
		// Tukey's Ninther, median of three medians of three.
		s := (hi - lo) / 8
		medianOfThreeStrings(rcv, less, lo, lo+s, lo+2*s)
		medianOfThreeStrings(rcv, less, m, m-s, m+s)
		medianOfThreeStrings(rcv, less, hi-1, hi-1-s, hi-1-2*s)
	}
	medianOfThreeStrings(rcv, less, lo, m, hi-1)

	// Invariants are:
	//	rcv[lo] = pivot (set up by ChoosePivot)
	//	rcv[lo <= i < a] = pivot
	//	rcv[a <= i < b] < pivot
	//	rcv[b <= i < c] is unexamined
	//	rcv[c <= i < d] > pivot
	//	rcv[d <= i < hi] = pivot
	//
	// Once b meets c, can swap the "= pivot" sections
	// into the middle of the slice.
	pivot := lo
	a, b, c, d := lo+1, lo+1, hi, hi
	for {
		for b < c {
			if less(rcv[b], rcv[pivot]) { // rcv[b] < pivot
				b++
			} else if !less(rcv[pivot], rcv[b]) { // rcv[b] = pivot
				swapStrings(rcv, a, b)
				a++
				b++
			} else {
				break
			}
		}
		for b < c {
			if less(rcv[pivot], rcv[c-1]) { // rcv[c-1] > pivot
				c--
			} else if !less(rcv[c-1], rcv[pivot]) { // rcv[c-1] = pivot
				swapStrings(rcv, c-1, d-1)
				c--
				d--
			} else {
				break
			}
		}
		if b >= c {
			break
		}
		// rcv[b] > pivot; rcv[c-1] < pivot
		swapStrings(rcv, b, c-1)
		b++
		c--
	}

	min := func(a, b int) int {
		if a < b {
			return a
		}
		return b
	}

	n := min(b-a, a-lo)
	swapRangeStrings(rcv, lo, b-n, n)

	n = min(hi-d, d-c)
	swapRangeStrings(rcv, c, hi-n, n)

	return lo + b - a, hi - (d - c)
}

func quickSortStrings(rcv Strings, less func(string, string) bool, a, b, maxDepth int) {
	for b-a > 7 {
		if maxDepth == 0 {
			heapSortStrings(rcv, less, a, b)
			return
		}
		maxDepth--
		mlo, mhi := doPivotStrings(rcv, less, a, b)
		// Avoiding recursion on the larger subproblem guarantees
		// a stack depth of at most lg(b-a).
		if mlo-a < b-mhi {
			quickSortStrings(rcv, less, a, mlo, maxDepth)
			a = mhi // i.e., quickSortStrings(rcv, mhi, b)
		} else {
			quickSortStrings(rcv, less, mhi, b, maxDepth)
			b = mlo // i.e., quickSortStrings(rcv, a, mlo)
		}
	}
	if b-a > 1 {
		insertionSortStrings(rcv, less, a, b)
	}
}

// The primary type that represents a set
type StringSet map[string]struct{}

// Creates and returns a reference to an empty set.
func NewStringSet() StringSet {
	return make(StringSet)
}

// Creates and returns a reference to a set from an existing slice
func NewStringSetFromSlice(s []string) StringSet {
	a := NewStringSet()
	for _, item := range s {
		a.Add(item)
	}
	return a
}

// Adds an item to the current set if it doesn't already exist in the set.
func (set StringSet) Add(i string) bool {
	_, found := set[i]
	set[i] = struct{}{}
	return !found //False if it existed already
}

// Determines if a given item is already in the set.
func (set StringSet) Contains(i string) bool {
	_, found := set[i]
	return found
}

// Determines if the given items are all in the set
func (set StringSet) ContainsAll(i ...string) bool {
	allSet := NewStringSetFromSlice(i)
	if allSet.IsSubset(set) {
		return true
	}
	return false
}

// Determines if every item in the other set is in this set.
func (set StringSet) IsSubset(other StringSet) bool {
	for elem := range set {
		if !other.Contains(elem) {
			return false
		}
	}
	return true
}

// Determines if every item of this set is in the other set.
func (set StringSet) IsSuperset(other StringSet) bool {
	return other.IsSubset(set)
}

// Returns a new set with all items in both sets.
func (set StringSet) Union(other StringSet) StringSet {
	unionedSet := NewStringSet()

	for elem := range set {
		unionedSet.Add(elem)
	}
	for elem := range other {
		unionedSet.Add(elem)
	}
	return unionedSet
}

// Returns a new set with items that exist only in both sets.
func (set StringSet) Intersect(other StringSet) StringSet {
	intersection := NewStringSet()
	// loop over smaller set
	if set.Cardinality() < other.Cardinality() {
		for elem := range set {
			if other.Contains(elem) {
				intersection.Add(elem)
			}
		}
	} else {
		for elem := range other {
			if set.Contains(elem) {
				intersection.Add(elem)
			}
		}
	}
	return intersection
}

// Returns a new set with items in the current set but not in the other set
func (set StringSet) Difference(other StringSet) StringSet {
	differencedSet := NewStringSet()
	for elem := range set {
		if !other.Contains(elem) {
			differencedSet.Add(elem)
		}
	}
	return differencedSet
}

// Returns a new set with items in the current set or the other set but not in both.
func (set StringSet) SymmetricDifference(other StringSet) StringSet {
	aDiff := set.Difference(other)
	bDiff := other.Difference(set)
	return aDiff.Union(bDiff)
}

// Clears the entire set to be the empty set.
func (set *StringSet) Clear() {
	*set = make(StringSet)
}

// Allows the removal of a single item in the set.
func (set StringSet) Remove(i string) {
	delete(set, i)
}

// Cardinality returns how many items are currently in the set.
func (set StringSet) Cardinality() int {
	return len(set)
}

// Iter() returns a channel of type string that you can range over.
func (set StringSet) Iter() <-chan string {
	ch := make(chan string)
	go func() {
		for elem := range set {
			ch <- elem
		}
		close(ch)
	}()

	return ch
}

// Equal determines if two sets are equal to each other.
// If they both are the same size and have the same items they are considered equal.
// Order of items is not relevent for sets to be equal.
func (set StringSet) Equal(other StringSet) bool {
	if set.Cardinality() != other.Cardinality() {
		return false
	}
	for elem := range set {
		if !other.Contains(elem) {
			return false
		}
	}
	return true
}

// Returns a clone of the set.
// Does NOT clone the underlying elements.
func (set StringSet) Clone() StringSet {
	clonedSet := NewStringSet()
	for elem := range set {
		clonedSet.Add(elem)
	}
	return clonedSet
}

// StringElement is an element of a linked list.
type StringElement struct {
	// Next and previous pointers in the doubly-linked list of elements.
	// To simplify the implementation, internally a list l is implemented
	// as a ring, such that &l.root is both the next element of the last
	// list element (l.Back()) and the previous element of the first list
	// element (l.Front()).
	next, prev *StringElement

	// The list to which this element belongs.
	list *StringList

	// The value stored with this element.
	Value string
}

// Next returns the next list element or nil.
func (e *StringElement) Next() *StringElement {
	if p := e.next; e.list != nil && p != &e.list.root {
		return p
	}
	return nil
}

// Prev returns the previous list element or nil.
func (e *StringElement) Prev() *StringElement {
	if p := e.prev; e.list != nil && p != &e.list.root {
		return p
	}
	return nil
}

// StringList represents a doubly linked list.
// The zero value for StringList is an empty list ready to use.
type StringList struct {
	root StringElement // sentinel list element, only &root, root.prev, and root.next are used
	len  int           // current list length excluding (this) sentinel element
}

// Init initializes or clears list l.
func (l *StringList) Init() *StringList {
	l.root.next = &l.root
	l.root.prev = &l.root
	l.len = 0
	return l
}

// New returns an initialized list.
func NewStringList() *StringList { return new(StringList).Init() }

// Len returns the number of elements of list l.
// The complexity is O(1).
func (l *StringList) Len() int { return l.len }

// Front returns the first element of list l or nil.
func (l *StringList) Front() *StringElement {
	if l.len == 0 {
		return nil
	}
	return l.root.next
}

// Back returns the last element of list l or nil.
func (l *StringList) Back() *StringElement {
	if l.len == 0 {
		return nil
	}
	return l.root.prev
}

// lazyInit lazily initializes a zero StringList value.
func (l *StringList) lazyInit() {
	if l.root.next == nil {
		l.Init()
	}
}

// insert inserts e after at, increments l.len, and returns e.
func (l *StringList) insert(e, at *StringElement) *StringElement {
	n := at.next
	at.next = e
	e.prev = at
	e.next = n
	n.prev = e
	e.list = l
	l.len++
	return e
}

// insertValue is a convenience wrapper for insert(&StringElement{Value: v}, at).
func (l *StringList) insertValue(v string, at *StringElement) *StringElement {
	return l.insert(&StringElement{Value: v}, at)
}

// remove removes e from its list, decrements l.len, and returns e.
func (l *StringList) remove(e *StringElement) *StringElement {
	e.prev.next = e.next
	e.next.prev = e.prev
	e.next = nil // avoid memory leaks
	e.prev = nil // avoid memory leaks
	e.list = nil
	l.len--
	return e
}

// Remove removes e from l if e is an element of list l.
// It returns the element value e.Value.
func (l *StringList) Remove(e *StringElement) string {
	if e.list == l {
		// if e.list == l, l must have been initialized when e was inserted
		// in l or l == nil (e is a zero StringElement) and l.remove will crash
		l.remove(e)
	}
	return e.Value
}

// PushFront inserts a new element e with value v at the front of list l and returns e.
func (l *StringList) PushFront(v string) *StringElement {
	l.lazyInit()
	return l.insertValue(v, &l.root)
}

// PushBack inserts a new element e with value v at the back of list l and returns e.
func (l *StringList) PushBack(v string) *StringElement {
	l.lazyInit()
	return l.insertValue(v, l.root.prev)
}

// InsertBefore inserts a new element e with value v immediately before mark and returns e.
// If mark is not an element of l, the list is not modified.
func (l *StringList) InsertBefore(v string, mark *StringElement) *StringElement {
	if mark.list != l {
		return nil
	}
	// see comment in StringList.Remove about initialization of l
	return l.insertValue(v, mark.prev)
}

// InsertAfter inserts a new element e with value v immediately after mark and returns e.
// If mark is not an element of l, the list is not modified.
func (l *StringList) InsertAfter(v string, mark *StringElement) *StringElement {
	if mark.list != l {
		return nil
	}
	// see comment in StringList.Remove about initialization of l
	return l.insertValue(v, mark)
}

// MoveToFront moves element e to the front of list l.
// If e is not an element of l, the list is not modified.
func (l *StringList) MoveToFront(e *StringElement) {
	if e.list != l || l.root.next == e {
		return
	}
	// see comment in StringList.Remove about initialization of l
	l.insert(l.remove(e), &l.root)
}

// MoveToBack moves element e to the back of list l.
// If e is not an element of l, the list is not modified.
func (l *StringList) MoveToBack(e *StringElement) {
	if e.list != l || l.root.prev == e {
		return
	}
	// see comment in StringList.Remove about initialization of l
	l.insert(l.remove(e), l.root.prev)
}

// MoveBefore moves element e to its new position before mark.
// If e or mark is not an element of l, or e == mark, the list is not modified.
func (l *StringList) MoveBefore(e, mark *StringElement) {
	if e.list != l || e == mark || mark.list != l {
		return
	}
	l.insert(l.remove(e), mark.prev)
}

// MoveAfter moves element e to its new position after mark.
// If e is not an element of l, or e == mark, the list is not modified.
func (l *StringList) MoveAfter(e, mark *StringElement) {
	if e.list != l || e == mark || mark.list != l {
		return
	}
	l.insert(l.remove(e), mark)
}

// PushBackList inserts a copy of an other list at the back of list l.
// The lists l and other may be the same.
func (l *StringList) PushBackList(other *StringList) {
	l.lazyInit()
	for i, e := other.Len(), other.Front(); i > 0; i, e = i-1, e.Next() {
		l.insertValue(e.Value, l.root.prev)
	}
}

// PushFrontList inserts a copy of an other list at the front of list l.
// The lists l and other may be the same.
func (l *StringList) PushFrontList(other *StringList) {
	l.lazyInit()
	for i, e := other.Len(), other.Back(); i > 0; i, e = i-1, e.Prev() {
		l.insertValue(e.Value, &l.root)
	}
}

// A Ring is an element of a circular list, or ring.
// Rings do not have a beginning or end; a pointer to any ring element
// serves as reference to the entire ring. Empty rings are represented
// as nil Ring pointers. The zero value for a Ring is a one-element
// ring with a nil Value.
//
type StringRing struct {
	next, prev *StringRing
	Value      string // for use by client; untouched by this library
}

func (r *StringRing) init() *StringRing {
	r.next = r
	r.prev = r
	return r
}

// Next returns the next ring element. r must not be empty.
func (r *StringRing) Next() *StringRing {
	if r.next == nil {
		return r.init()
	}
	return r.next
}

// Prev returns the previous ring element. r must not be empty.
func (r *StringRing) Prev() *StringRing {
	if r.next == nil {
		return r.init()
	}
	return r.prev
}

// Move moves n % r.Len() elements backward (n < 0) or forward (n >= 0)
// in the ring and returns that ring element. r must not be empty.
//
func (r *StringRing) Move(n int) *StringRing {
	if r.next == nil {
		return r.init()
	}
	switch {
	case n < 0:
		for ; n < 0; n++ {
			r = r.prev
		}
	case n > 0:
		for ; n > 0; n-- {
			r = r.next
		}
	}
	return r
}

// New creates a ring of n elements.
func NewStringRing(n int) *StringRing {
	if n <= 0 {
		return nil
	}
	r := new(StringRing)
	p := r
	for i := 1; i < n; i++ {
		p.next = &StringRing{prev: p}
		p = p.next
	}
	p.next = r
	r.prev = p
	return r
}

// Link connects ring r with ring s such that r.Next()
// becomes s and returns the original value for r.Next().
// r must not be empty.
//
// If r and s point to the same ring, linking
// them removes the elements between r and s from the ring.
// The removed elements form a subring and the result is a
// reference to that subring (if no elements were removed,
// the result is still the original value for r.Next(),
// and not nil).
//
// If r and s point to different rings, linking
// them creates a single ring with the elements of s inserted
// after r. The result points to the element following the
// last element of s after insertion.
//
func (r *StringRing) Link(s *StringRing) *StringRing {
	n := r.Next()
	if s != nil {
		p := s.Prev()
		// Note: Cannot use multiple assignment because
		// evaluation order of LHS is not specified.
		r.next = s
		s.prev = r
		n.prev = p
		p.next = n
	}
	return n
}

// Unlink removes n % r.Len() elements from the ring r, starting
// at r.Next(). If n % r.Len() == 0, r remains unchanged.
// The result is the removed subring. r must not be empty.
//
func (r *StringRing) Unlink(n int) *StringRing {
	if n <= 0 {
		return nil
	}
	return r.Link(r.Move(n + 1))
}

// Len computes the number of elements in ring r.
// It executes in time proportional to the number of elements.
//
func (r *StringRing) Len() int {
	n := 0
	if r != nil {
		n = 1
		for p := r.Next(); p != r; p = p.next {
			n++
		}
	}
	return n
}

// Do calls function f on each element of the ring, in forward order.
// The behavior of Do is undefined if f changes *r.
func (r *StringRing) Do(f func(string)) {
	if r != nil {
		f(r.Value)
		for p := r.Next(); p != r; p = p.next {
			f(p.Value)
		}
	}
}