github.com/gogf/gf@v1.16.9/container/garray/garray_sorted_str.go (about)

     1  // Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
     2  //
     3  // This Source Code Form is subject to the terms of the MIT License.
     4  // If a copy of the MIT was not distributed with this file,
     5  // You can obtain one at https://github.com/gogf/gf.
     6  
     7  package garray
     8  
     9  import (
    10  	"bytes"
    11  	"github.com/gogf/gf/internal/json"
    12  	"github.com/gogf/gf/text/gstr"
    13  	"math"
    14  	"sort"
    15  	"strings"
    16  
    17  	"github.com/gogf/gf/internal/rwmutex"
    18  	"github.com/gogf/gf/util/gconv"
    19  	"github.com/gogf/gf/util/grand"
    20  )
    21  
    22  // SortedStrArray is a golang sorted string array with rich features.
    23  // It is using increasing order in default, which can be changed by
    24  // setting it a custom comparator.
    25  // It contains a concurrent-safe/unsafe switch, which should be set
    26  // when its initialization and cannot be changed then.
    27  type SortedStrArray struct {
    28  	mu         rwmutex.RWMutex
    29  	array      []string
    30  	unique     bool                  // Whether enable unique feature(false)
    31  	comparator func(a, b string) int // Comparison function(it returns -1: a < b; 0: a == b; 1: a > b)
    32  }
    33  
    34  // NewSortedStrArray creates and returns an empty sorted array.
    35  // The parameter `safe` is used to specify whether using array in concurrent-safety,
    36  // which is false in default.
    37  func NewSortedStrArray(safe ...bool) *SortedStrArray {
    38  	return NewSortedStrArraySize(0, safe...)
    39  }
    40  
    41  // NewSortedStrArrayComparator creates and returns an empty sorted array with specified comparator.
    42  // The parameter `safe` is used to specify whether using array in concurrent-safety which is false in default.
    43  func NewSortedStrArrayComparator(comparator func(a, b string) int, safe ...bool) *SortedStrArray {
    44  	array := NewSortedStrArray(safe...)
    45  	array.comparator = comparator
    46  	return array
    47  }
    48  
    49  // NewSortedStrArraySize create and returns an sorted array with given size and cap.
    50  // The parameter `safe` is used to specify whether using array in concurrent-safety,
    51  // which is false in default.
    52  func NewSortedStrArraySize(cap int, safe ...bool) *SortedStrArray {
    53  	return &SortedStrArray{
    54  		mu:         rwmutex.Create(safe...),
    55  		array:      make([]string, 0, cap),
    56  		comparator: defaultComparatorStr,
    57  	}
    58  }
    59  
    60  // NewSortedStrArrayFrom creates and returns an sorted array with given slice `array`.
    61  // The parameter `safe` is used to specify whether using array in concurrent-safety,
    62  // which is false in default.
    63  func NewSortedStrArrayFrom(array []string, safe ...bool) *SortedStrArray {
    64  	a := NewSortedStrArraySize(0, safe...)
    65  	a.array = array
    66  	quickSortStr(a.array, a.getComparator())
    67  	return a
    68  }
    69  
    70  // NewSortedStrArrayFromCopy creates and returns an sorted array from a copy of given slice `array`.
    71  // The parameter `safe` is used to specify whether using array in concurrent-safety,
    72  // which is false in default.
    73  func NewSortedStrArrayFromCopy(array []string, safe ...bool) *SortedStrArray {
    74  	newArray := make([]string, len(array))
    75  	copy(newArray, array)
    76  	return NewSortedStrArrayFrom(newArray, safe...)
    77  }
    78  
    79  // SetArray sets the underlying slice array with the given `array`.
    80  func (a *SortedStrArray) SetArray(array []string) *SortedStrArray {
    81  	a.mu.Lock()
    82  	defer a.mu.Unlock()
    83  	a.array = array
    84  	quickSortStr(a.array, a.getComparator())
    85  	return a
    86  }
    87  
    88  // At returns the value by the specified index.
    89  // If the given `index` is out of range of the array, it returns an empty string.
    90  func (a *SortedStrArray) At(index int) (value string) {
    91  	value, _ = a.Get(index)
    92  	return
    93  }
    94  
    95  // Sort sorts the array in increasing order.
    96  // The parameter `reverse` controls whether sort
    97  // in increasing order(default) or decreasing order.
    98  func (a *SortedStrArray) Sort() *SortedStrArray {
    99  	a.mu.Lock()
   100  	defer a.mu.Unlock()
   101  	quickSortStr(a.array, a.getComparator())
   102  	return a
   103  }
   104  
   105  // Add adds one or multiple values to sorted array, the array always keeps sorted.
   106  // It's alias of function Append, see Append.
   107  func (a *SortedStrArray) Add(values ...string) *SortedStrArray {
   108  	return a.Append(values...)
   109  }
   110  
   111  // Append adds one or multiple values to sorted array, the array always keeps sorted.
   112  func (a *SortedStrArray) Append(values ...string) *SortedStrArray {
   113  	if len(values) == 0 {
   114  		return a
   115  	}
   116  	a.mu.Lock()
   117  	defer a.mu.Unlock()
   118  	for _, value := range values {
   119  		index, cmp := a.binSearch(value, false)
   120  		if a.unique && cmp == 0 {
   121  			continue
   122  		}
   123  		if index < 0 {
   124  			a.array = append(a.array, value)
   125  			continue
   126  		}
   127  		if cmp > 0 {
   128  			index++
   129  		}
   130  		rear := append([]string{}, a.array[index:]...)
   131  		a.array = append(a.array[0:index], value)
   132  		a.array = append(a.array, rear...)
   133  	}
   134  	return a
   135  }
   136  
   137  // Get returns the value by the specified index.
   138  // If the given `index` is out of range of the array, the `found` is false.
   139  func (a *SortedStrArray) Get(index int) (value string, found bool) {
   140  	a.mu.RLock()
   141  	defer a.mu.RUnlock()
   142  	if index < 0 || index >= len(a.array) {
   143  		return "", false
   144  	}
   145  	return a.array[index], true
   146  }
   147  
   148  // Remove removes an item by index.
   149  // If the given `index` is out of range of the array, the `found` is false.
   150  func (a *SortedStrArray) Remove(index int) (value string, found bool) {
   151  	a.mu.Lock()
   152  	defer a.mu.Unlock()
   153  	return a.doRemoveWithoutLock(index)
   154  }
   155  
   156  // doRemoveWithoutLock removes an item by index without lock.
   157  func (a *SortedStrArray) doRemoveWithoutLock(index int) (value string, found bool) {
   158  	if index < 0 || index >= len(a.array) {
   159  		return "", false
   160  	}
   161  	// Determine array boundaries when deleting to improve deletion efficiency.
   162  	if index == 0 {
   163  		value := a.array[0]
   164  		a.array = a.array[1:]
   165  		return value, true
   166  	} else if index == len(a.array)-1 {
   167  		value := a.array[index]
   168  		a.array = a.array[:index]
   169  		return value, true
   170  	}
   171  	// If it is a non-boundary delete,
   172  	// it will involve the creation of an array,
   173  	// then the deletion is less efficient.
   174  	value = a.array[index]
   175  	a.array = append(a.array[:index], a.array[index+1:]...)
   176  	return value, true
   177  }
   178  
   179  // RemoveValue removes an item by value.
   180  // It returns true if value is found in the array, or else false if not found.
   181  func (a *SortedStrArray) RemoveValue(value string) bool {
   182  	if i := a.Search(value); i != -1 {
   183  		a.Remove(i)
   184  		return true
   185  	}
   186  	return false
   187  }
   188  
   189  // PopLeft pops and returns an item from the beginning of array.
   190  // Note that if the array is empty, the `found` is false.
   191  func (a *SortedStrArray) PopLeft() (value string, found bool) {
   192  	a.mu.Lock()
   193  	defer a.mu.Unlock()
   194  	if len(a.array) == 0 {
   195  		return "", false
   196  	}
   197  	value = a.array[0]
   198  	a.array = a.array[1:]
   199  	return value, true
   200  }
   201  
   202  // PopRight pops and returns an item from the end of array.
   203  // Note that if the array is empty, the `found` is false.
   204  func (a *SortedStrArray) PopRight() (value string, found bool) {
   205  	a.mu.Lock()
   206  	defer a.mu.Unlock()
   207  	index := len(a.array) - 1
   208  	if index < 0 {
   209  		return "", false
   210  	}
   211  	value = a.array[index]
   212  	a.array = a.array[:index]
   213  	return value, true
   214  }
   215  
   216  // PopRand randomly pops and return an item out of array.
   217  // Note that if the array is empty, the `found` is false.
   218  func (a *SortedStrArray) PopRand() (value string, found bool) {
   219  	a.mu.Lock()
   220  	defer a.mu.Unlock()
   221  	return a.doRemoveWithoutLock(grand.Intn(len(a.array)))
   222  }
   223  
   224  // PopRands randomly pops and returns `size` items out of array.
   225  // If the given `size` is greater than size of the array, it returns all elements of the array.
   226  // Note that if given `size` <= 0 or the array is empty, it returns nil.
   227  func (a *SortedStrArray) PopRands(size int) []string {
   228  	a.mu.Lock()
   229  	defer a.mu.Unlock()
   230  	if size <= 0 || len(a.array) == 0 {
   231  		return nil
   232  	}
   233  	if size >= len(a.array) {
   234  		size = len(a.array)
   235  	}
   236  	array := make([]string, size)
   237  	for i := 0; i < size; i++ {
   238  		array[i], _ = a.doRemoveWithoutLock(grand.Intn(len(a.array)))
   239  	}
   240  	return array
   241  }
   242  
   243  // PopLefts pops and returns `size` items from the beginning of array.
   244  // If the given `size` is greater than size of the array, it returns all elements of the array.
   245  // Note that if given `size` <= 0 or the array is empty, it returns nil.
   246  func (a *SortedStrArray) PopLefts(size int) []string {
   247  	a.mu.Lock()
   248  	defer a.mu.Unlock()
   249  	if size <= 0 || len(a.array) == 0 {
   250  		return nil
   251  	}
   252  	if size >= len(a.array) {
   253  		array := a.array
   254  		a.array = a.array[:0]
   255  		return array
   256  	}
   257  	value := a.array[0:size]
   258  	a.array = a.array[size:]
   259  	return value
   260  }
   261  
   262  // PopRights pops and returns `size` items from the end of array.
   263  // If the given `size` is greater than size of the array, it returns all elements of the array.
   264  // Note that if given `size` <= 0 or the array is empty, it returns nil.
   265  func (a *SortedStrArray) PopRights(size int) []string {
   266  	a.mu.Lock()
   267  	defer a.mu.Unlock()
   268  	if size <= 0 || len(a.array) == 0 {
   269  		return nil
   270  	}
   271  	index := len(a.array) - size
   272  	if index <= 0 {
   273  		array := a.array
   274  		a.array = a.array[:0]
   275  		return array
   276  	}
   277  	value := a.array[index:]
   278  	a.array = a.array[:index]
   279  	return value
   280  }
   281  
   282  // Range picks and returns items by range, like array[start:end].
   283  // Notice, if in concurrent-safe usage, it returns a copy of slice;
   284  // else a pointer to the underlying data.
   285  //
   286  // If `end` is negative, then the offset will start from the end of array.
   287  // If `end` is omitted, then the sequence will have everything from start up
   288  // until the end of the array.
   289  func (a *SortedStrArray) Range(start int, end ...int) []string {
   290  	a.mu.RLock()
   291  	defer a.mu.RUnlock()
   292  	offsetEnd := len(a.array)
   293  	if len(end) > 0 && end[0] < offsetEnd {
   294  		offsetEnd = end[0]
   295  	}
   296  	if start > offsetEnd {
   297  		return nil
   298  	}
   299  	if start < 0 {
   300  		start = 0
   301  	}
   302  	array := ([]string)(nil)
   303  	if a.mu.IsSafe() {
   304  		array = make([]string, offsetEnd-start)
   305  		copy(array, a.array[start:offsetEnd])
   306  	} else {
   307  		array = a.array[start:offsetEnd]
   308  	}
   309  	return array
   310  }
   311  
   312  // SubSlice returns a slice of elements from the array as specified
   313  // by the `offset` and `size` parameters.
   314  // If in concurrent safe usage, it returns a copy of the slice; else a pointer.
   315  //
   316  // If offset is non-negative, the sequence will start at that offset in the array.
   317  // If offset is negative, the sequence will start that far from the end of the array.
   318  //
   319  // If length is given and is positive, then the sequence will have up to that many elements in it.
   320  // If the array is shorter than the length, then only the available array elements will be present.
   321  // If length is given and is negative then the sequence will stop that many elements from the end of the array.
   322  // If it is omitted, then the sequence will have everything from offset up until the end of the array.
   323  //
   324  // Any possibility crossing the left border of array, it will fail.
   325  func (a *SortedStrArray) SubSlice(offset int, length ...int) []string {
   326  	a.mu.RLock()
   327  	defer a.mu.RUnlock()
   328  	size := len(a.array)
   329  	if len(length) > 0 {
   330  		size = length[0]
   331  	}
   332  	if offset > len(a.array) {
   333  		return nil
   334  	}
   335  	if offset < 0 {
   336  		offset = len(a.array) + offset
   337  		if offset < 0 {
   338  			return nil
   339  		}
   340  	}
   341  	if size < 0 {
   342  		offset += size
   343  		size = -size
   344  		if offset < 0 {
   345  			return nil
   346  		}
   347  	}
   348  	end := offset + size
   349  	if end > len(a.array) {
   350  		end = len(a.array)
   351  		size = len(a.array) - offset
   352  	}
   353  	if a.mu.IsSafe() {
   354  		s := make([]string, size)
   355  		copy(s, a.array[offset:])
   356  		return s
   357  	} else {
   358  		return a.array[offset:end]
   359  	}
   360  }
   361  
   362  // Sum returns the sum of values in an array.
   363  func (a *SortedStrArray) Sum() (sum int) {
   364  	a.mu.RLock()
   365  	defer a.mu.RUnlock()
   366  	for _, v := range a.array {
   367  		sum += gconv.Int(v)
   368  	}
   369  	return
   370  }
   371  
   372  // Len returns the length of array.
   373  func (a *SortedStrArray) Len() int {
   374  	a.mu.RLock()
   375  	length := len(a.array)
   376  	a.mu.RUnlock()
   377  	return length
   378  }
   379  
   380  // Slice returns the underlying data of array.
   381  // Note that, if it's in concurrent-safe usage, it returns a copy of underlying data,
   382  // or else a pointer to the underlying data.
   383  func (a *SortedStrArray) Slice() []string {
   384  	array := ([]string)(nil)
   385  	if a.mu.IsSafe() {
   386  		a.mu.RLock()
   387  		defer a.mu.RUnlock()
   388  		array = make([]string, len(a.array))
   389  		copy(array, a.array)
   390  	} else {
   391  		array = a.array
   392  	}
   393  	return array
   394  }
   395  
   396  // Interfaces returns current array as []interface{}.
   397  func (a *SortedStrArray) Interfaces() []interface{} {
   398  	a.mu.RLock()
   399  	defer a.mu.RUnlock()
   400  	array := make([]interface{}, len(a.array))
   401  	for k, v := range a.array {
   402  		array[k] = v
   403  	}
   404  	return array
   405  }
   406  
   407  // Contains checks whether a value exists in the array.
   408  func (a *SortedStrArray) Contains(value string) bool {
   409  	return a.Search(value) != -1
   410  }
   411  
   412  // ContainsI checks whether a value exists in the array with case-insensitively.
   413  // Note that it internally iterates the whole array to do the comparison with case-insensitively.
   414  func (a *SortedStrArray) ContainsI(value string) bool {
   415  	a.mu.RLock()
   416  	defer a.mu.RUnlock()
   417  	if len(a.array) == 0 {
   418  		return false
   419  	}
   420  	for _, v := range a.array {
   421  		if strings.EqualFold(v, value) {
   422  			return true
   423  		}
   424  	}
   425  	return false
   426  }
   427  
   428  // Search searches array by `value`, returns the index of `value`,
   429  // or returns -1 if not exists.
   430  func (a *SortedStrArray) Search(value string) (index int) {
   431  	if i, r := a.binSearch(value, true); r == 0 {
   432  		return i
   433  	}
   434  	return -1
   435  }
   436  
   437  // Binary search.
   438  // It returns the last compared index and the result.
   439  // If `result` equals to 0, it means the value at `index` is equals to `value`.
   440  // If `result` lesser than 0, it means the value at `index` is lesser than `value`.
   441  // If `result` greater than 0, it means the value at `index` is greater than `value`.
   442  func (a *SortedStrArray) binSearch(value string, lock bool) (index int, result int) {
   443  	if lock {
   444  		a.mu.RLock()
   445  		defer a.mu.RUnlock()
   446  	}
   447  	if len(a.array) == 0 {
   448  		return -1, -2
   449  	}
   450  	min := 0
   451  	max := len(a.array) - 1
   452  	mid := 0
   453  	cmp := -2
   454  	for min <= max {
   455  		mid = min + int((max-min)/2)
   456  		cmp = a.getComparator()(value, a.array[mid])
   457  		switch {
   458  		case cmp < 0:
   459  			max = mid - 1
   460  		case cmp > 0:
   461  			min = mid + 1
   462  		default:
   463  			return mid, cmp
   464  		}
   465  	}
   466  	return mid, cmp
   467  }
   468  
   469  // SetUnique sets unique mark to the array,
   470  // which means it does not contain any repeated items.
   471  // It also do unique check, remove all repeated items.
   472  func (a *SortedStrArray) SetUnique(unique bool) *SortedStrArray {
   473  	oldUnique := a.unique
   474  	a.unique = unique
   475  	if unique && oldUnique != unique {
   476  		a.Unique()
   477  	}
   478  	return a
   479  }
   480  
   481  // Unique uniques the array, clear repeated items.
   482  func (a *SortedStrArray) Unique() *SortedStrArray {
   483  	a.mu.Lock()
   484  	defer a.mu.Unlock()
   485  	if len(a.array) == 0 {
   486  		return a
   487  	}
   488  	i := 0
   489  	for {
   490  		if i == len(a.array)-1 {
   491  			break
   492  		}
   493  		if a.getComparator()(a.array[i], a.array[i+1]) == 0 {
   494  			a.array = append(a.array[:i+1], a.array[i+1+1:]...)
   495  		} else {
   496  			i++
   497  		}
   498  	}
   499  	return a
   500  }
   501  
   502  // Clone returns a new array, which is a copy of current array.
   503  func (a *SortedStrArray) Clone() (newArray *SortedStrArray) {
   504  	a.mu.RLock()
   505  	array := make([]string, len(a.array))
   506  	copy(array, a.array)
   507  	a.mu.RUnlock()
   508  	return NewSortedStrArrayFrom(array, a.mu.IsSafe())
   509  }
   510  
   511  // Clear deletes all items of current array.
   512  func (a *SortedStrArray) Clear() *SortedStrArray {
   513  	a.mu.Lock()
   514  	if len(a.array) > 0 {
   515  		a.array = make([]string, 0)
   516  	}
   517  	a.mu.Unlock()
   518  	return a
   519  }
   520  
   521  // LockFunc locks writing by callback function `f`.
   522  func (a *SortedStrArray) LockFunc(f func(array []string)) *SortedStrArray {
   523  	a.mu.Lock()
   524  	defer a.mu.Unlock()
   525  	f(a.array)
   526  	return a
   527  }
   528  
   529  // RLockFunc locks reading by callback function `f`.
   530  func (a *SortedStrArray) RLockFunc(f func(array []string)) *SortedStrArray {
   531  	a.mu.RLock()
   532  	defer a.mu.RUnlock()
   533  	f(a.array)
   534  	return a
   535  }
   536  
   537  // Merge merges `array` into current array.
   538  // The parameter `array` can be any garray or slice type.
   539  // The difference between Merge and Append is Append supports only specified slice type,
   540  // but Merge supports more parameter types.
   541  func (a *SortedStrArray) Merge(array interface{}) *SortedStrArray {
   542  	return a.Add(gconv.Strings(array)...)
   543  }
   544  
   545  // Chunk splits an array into multiple arrays,
   546  // the size of each array is determined by `size`.
   547  // The last chunk may contain less than size elements.
   548  func (a *SortedStrArray) Chunk(size int) [][]string {
   549  	if size < 1 {
   550  		return nil
   551  	}
   552  	a.mu.RLock()
   553  	defer a.mu.RUnlock()
   554  	length := len(a.array)
   555  	chunks := int(math.Ceil(float64(length) / float64(size)))
   556  	var n [][]string
   557  	for i, end := 0, 0; chunks > 0; chunks-- {
   558  		end = (i + 1) * size
   559  		if end > length {
   560  			end = length
   561  		}
   562  		n = append(n, a.array[i*size:end])
   563  		i++
   564  	}
   565  	return n
   566  }
   567  
   568  // Rand randomly returns one item from array(no deleting).
   569  func (a *SortedStrArray) Rand() (value string, found bool) {
   570  	a.mu.RLock()
   571  	defer a.mu.RUnlock()
   572  	if len(a.array) == 0 {
   573  		return "", false
   574  	}
   575  	return a.array[grand.Intn(len(a.array))], true
   576  }
   577  
   578  // Rands randomly returns `size` items from array(no deleting).
   579  func (a *SortedStrArray) Rands(size int) []string {
   580  	a.mu.RLock()
   581  	defer a.mu.RUnlock()
   582  	if size <= 0 || len(a.array) == 0 {
   583  		return nil
   584  	}
   585  	array := make([]string, size)
   586  	for i := 0; i < size; i++ {
   587  		array[i] = a.array[grand.Intn(len(a.array))]
   588  	}
   589  	return array
   590  }
   591  
   592  // Join joins array elements with a string `glue`.
   593  func (a *SortedStrArray) Join(glue string) string {
   594  	a.mu.RLock()
   595  	defer a.mu.RUnlock()
   596  	if len(a.array) == 0 {
   597  		return ""
   598  	}
   599  	buffer := bytes.NewBuffer(nil)
   600  	for k, v := range a.array {
   601  		buffer.WriteString(v)
   602  		if k != len(a.array)-1 {
   603  			buffer.WriteString(glue)
   604  		}
   605  	}
   606  	return buffer.String()
   607  }
   608  
   609  // CountValues counts the number of occurrences of all values in the array.
   610  func (a *SortedStrArray) CountValues() map[string]int {
   611  	m := make(map[string]int)
   612  	a.mu.RLock()
   613  	defer a.mu.RUnlock()
   614  	for _, v := range a.array {
   615  		m[v]++
   616  	}
   617  	return m
   618  }
   619  
   620  // Iterator is alias of IteratorAsc.
   621  func (a *SortedStrArray) Iterator(f func(k int, v string) bool) {
   622  	a.IteratorAsc(f)
   623  }
   624  
   625  // IteratorAsc iterates the array readonly in ascending order with given callback function `f`.
   626  // If `f` returns true, then it continues iterating; or false to stop.
   627  func (a *SortedStrArray) IteratorAsc(f func(k int, v string) bool) {
   628  	a.mu.RLock()
   629  	defer a.mu.RUnlock()
   630  	for k, v := range a.array {
   631  		if !f(k, v) {
   632  			break
   633  		}
   634  	}
   635  }
   636  
   637  // IteratorDesc iterates the array readonly in descending order with given callback function `f`.
   638  // If `f` returns true, then it continues iterating; or false to stop.
   639  func (a *SortedStrArray) IteratorDesc(f func(k int, v string) bool) {
   640  	a.mu.RLock()
   641  	defer a.mu.RUnlock()
   642  	for i := len(a.array) - 1; i >= 0; i-- {
   643  		if !f(i, a.array[i]) {
   644  			break
   645  		}
   646  	}
   647  }
   648  
   649  // String returns current array as a string, which implements like json.Marshal does.
   650  func (a *SortedStrArray) String() string {
   651  	a.mu.RLock()
   652  	defer a.mu.RUnlock()
   653  	buffer := bytes.NewBuffer(nil)
   654  	buffer.WriteByte('[')
   655  	for k, v := range a.array {
   656  		buffer.WriteString(`"` + gstr.QuoteMeta(v, `"\`) + `"`)
   657  		if k != len(a.array)-1 {
   658  			buffer.WriteByte(',')
   659  		}
   660  	}
   661  	buffer.WriteByte(']')
   662  	return buffer.String()
   663  }
   664  
   665  // MarshalJSON implements the interface MarshalJSON for json.Marshal.
   666  // Note that do not use pointer as its receiver here.
   667  func (a SortedStrArray) MarshalJSON() ([]byte, error) {
   668  	a.mu.RLock()
   669  	defer a.mu.RUnlock()
   670  	return json.Marshal(a.array)
   671  }
   672  
   673  // UnmarshalJSON implements the interface UnmarshalJSON for json.Unmarshal.
   674  func (a *SortedStrArray) UnmarshalJSON(b []byte) error {
   675  	if a.comparator == nil {
   676  		a.array = make([]string, 0)
   677  		a.comparator = defaultComparatorStr
   678  	}
   679  	a.mu.Lock()
   680  	defer a.mu.Unlock()
   681  	if err := json.UnmarshalUseNumber(b, &a.array); err != nil {
   682  		return err
   683  	}
   684  	if a.array != nil {
   685  		sort.Strings(a.array)
   686  	}
   687  	return nil
   688  }
   689  
   690  // UnmarshalValue is an interface implement which sets any type of value for array.
   691  func (a *SortedStrArray) UnmarshalValue(value interface{}) (err error) {
   692  	if a.comparator == nil {
   693  		a.comparator = defaultComparatorStr
   694  	}
   695  	a.mu.Lock()
   696  	defer a.mu.Unlock()
   697  	switch value.(type) {
   698  	case string, []byte:
   699  		err = json.UnmarshalUseNumber(gconv.Bytes(value), &a.array)
   700  	default:
   701  		a.array = gconv.SliceStr(value)
   702  	}
   703  	if a.array != nil {
   704  		sort.Strings(a.array)
   705  	}
   706  	return err
   707  }
   708  
   709  // FilterEmpty removes all empty string value of the array.
   710  func (a *SortedStrArray) FilterEmpty() *SortedStrArray {
   711  	a.mu.Lock()
   712  	defer a.mu.Unlock()
   713  	for i := 0; i < len(a.array); {
   714  		if a.array[i] == "" {
   715  			a.array = append(a.array[:i], a.array[i+1:]...)
   716  		} else {
   717  			break
   718  		}
   719  	}
   720  	for i := len(a.array) - 1; i >= 0; {
   721  		if a.array[i] == "" {
   722  			a.array = append(a.array[:i], a.array[i+1:]...)
   723  		} else {
   724  			break
   725  		}
   726  	}
   727  	return a
   728  }
   729  
   730  // Walk applies a user supplied function `f` to every item of array.
   731  func (a *SortedStrArray) Walk(f func(value string) string) *SortedStrArray {
   732  	a.mu.Lock()
   733  	defer a.mu.Unlock()
   734  
   735  	// Keep the array always sorted.
   736  	defer quickSortStr(a.array, a.getComparator())
   737  
   738  	for i, v := range a.array {
   739  		a.array[i] = f(v)
   740  	}
   741  	return a
   742  }
   743  
   744  // IsEmpty checks whether the array is empty.
   745  func (a *SortedStrArray) IsEmpty() bool {
   746  	return a.Len() == 0
   747  }
   748  
   749  // getComparator returns the comparator if it's previously set,
   750  // or else it returns a default comparator.
   751  func (a *SortedStrArray) getComparator() func(a, b string) int {
   752  	if a.comparator == nil {
   753  		return defaultComparatorStr
   754  	}
   755  	return a.comparator
   756  }