github.com/gogf/gf/v2@v2.7.4/container/garray/garray_sorted_any.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  	"fmt"
    12  	"math"
    13  	"sort"
    14  
    15  	"github.com/gogf/gf/v2/internal/deepcopy"
    16  	"github.com/gogf/gf/v2/internal/empty"
    17  	"github.com/gogf/gf/v2/internal/json"
    18  	"github.com/gogf/gf/v2/internal/rwmutex"
    19  	"github.com/gogf/gf/v2/text/gstr"
    20  	"github.com/gogf/gf/v2/util/gconv"
    21  	"github.com/gogf/gf/v2/util/grand"
    22  	"github.com/gogf/gf/v2/util/gutil"
    23  )
    24  
    25  // SortedArray is a golang sorted array with rich features.
    26  // It is using increasing order in default, which can be changed by
    27  // setting it a custom comparator.
    28  // It contains a concurrent-safe/unsafe switch, which should be set
    29  // when its initialization and cannot be changed then.
    30  type SortedArray struct {
    31  	mu         rwmutex.RWMutex
    32  	array      []interface{}
    33  	unique     bool                       // Whether enable unique feature(false)
    34  	comparator func(a, b interface{}) int // Comparison function(it returns -1: a < b; 0: a == b; 1: a > b)
    35  }
    36  
    37  // NewSortedArray creates and returns an empty sorted array.
    38  // The parameter `safe` is used to specify whether using array in concurrent-safety, which is false in default.
    39  // The parameter `comparator` used to compare values to sort in array,
    40  // if it returns value < 0, means `a` < `b`; the `a` will be inserted before `b`;
    41  // if it returns value = 0, means `a` = `b`; the `a` will be replaced by     `b`;
    42  // if it returns value > 0, means `a` > `b`; the `a` will be inserted after  `b`;
    43  func NewSortedArray(comparator func(a, b interface{}) int, safe ...bool) *SortedArray {
    44  	return NewSortedArraySize(0, comparator, safe...)
    45  }
    46  
    47  // NewSortedArraySize create and returns an sorted array with given size and cap.
    48  // The parameter `safe` is used to specify whether using array in concurrent-safety,
    49  // which is false in default.
    50  func NewSortedArraySize(cap int, comparator func(a, b interface{}) int, safe ...bool) *SortedArray {
    51  	return &SortedArray{
    52  		mu:         rwmutex.Create(safe...),
    53  		array:      make([]interface{}, 0, cap),
    54  		comparator: comparator,
    55  	}
    56  }
    57  
    58  // NewSortedArrayRange creates and returns an array by a range from `start` to `end`
    59  // with step value `step`.
    60  func NewSortedArrayRange(start, end, step int, comparator func(a, b interface{}) int, safe ...bool) *SortedArray {
    61  	if step == 0 {
    62  		panic(fmt.Sprintf(`invalid step value: %d`, step))
    63  	}
    64  	slice := make([]interface{}, 0)
    65  	index := 0
    66  	for i := start; i <= end; i += step {
    67  		slice = append(slice, i)
    68  		index++
    69  	}
    70  	return NewSortedArrayFrom(slice, comparator, safe...)
    71  }
    72  
    73  // NewSortedArrayFrom creates and returns an sorted array with given slice `array`.
    74  // The parameter `safe` is used to specify whether using array in concurrent-safety,
    75  // which is false in default.
    76  func NewSortedArrayFrom(array []interface{}, comparator func(a, b interface{}) int, safe ...bool) *SortedArray {
    77  	a := NewSortedArraySize(0, comparator, safe...)
    78  	a.array = array
    79  	sort.Slice(a.array, func(i, j int) bool {
    80  		return a.getComparator()(a.array[i], a.array[j]) < 0
    81  	})
    82  	return a
    83  }
    84  
    85  // NewSortedArrayFromCopy creates and returns an sorted array from a copy of given slice `array`.
    86  // The parameter `safe` is used to specify whether using array in concurrent-safety,
    87  // which is false in default.
    88  func NewSortedArrayFromCopy(array []interface{}, comparator func(a, b interface{}) int, safe ...bool) *SortedArray {
    89  	newArray := make([]interface{}, len(array))
    90  	copy(newArray, array)
    91  	return NewSortedArrayFrom(newArray, comparator, safe...)
    92  }
    93  
    94  // At returns the value by the specified index.
    95  // If the given `index` is out of range of the array, it returns `nil`.
    96  func (a *SortedArray) At(index int) (value interface{}) {
    97  	value, _ = a.Get(index)
    98  	return
    99  }
   100  
   101  // SetArray sets the underlying slice array with the given `array`.
   102  func (a *SortedArray) SetArray(array []interface{}) *SortedArray {
   103  	a.mu.Lock()
   104  	defer a.mu.Unlock()
   105  	a.array = array
   106  	sort.Slice(a.array, func(i, j int) bool {
   107  		return a.getComparator()(a.array[i], a.array[j]) < 0
   108  	})
   109  	return a
   110  }
   111  
   112  // SetComparator sets/changes the comparator for sorting.
   113  // It resorts the array as the comparator is changed.
   114  func (a *SortedArray) SetComparator(comparator func(a, b interface{}) int) {
   115  	a.mu.Lock()
   116  	defer a.mu.Unlock()
   117  	a.comparator = comparator
   118  	sort.Slice(a.array, func(i, j int) bool {
   119  		return a.getComparator()(a.array[i], a.array[j]) < 0
   120  	})
   121  }
   122  
   123  // Sort sorts the array in increasing order.
   124  // The parameter `reverse` controls whether sort
   125  // in increasing order(default) or decreasing order
   126  func (a *SortedArray) Sort() *SortedArray {
   127  	a.mu.Lock()
   128  	defer a.mu.Unlock()
   129  	sort.Slice(a.array, func(i, j int) bool {
   130  		return a.getComparator()(a.array[i], a.array[j]) < 0
   131  	})
   132  	return a
   133  }
   134  
   135  // Add adds one or multiple values to sorted array, the array always keeps sorted.
   136  // It's alias of function Append, see Append.
   137  func (a *SortedArray) Add(values ...interface{}) *SortedArray {
   138  	return a.Append(values...)
   139  }
   140  
   141  // Append adds one or multiple values to sorted array, the array always keeps sorted.
   142  func (a *SortedArray) Append(values ...interface{}) *SortedArray {
   143  	if len(values) == 0 {
   144  		return a
   145  	}
   146  	a.mu.Lock()
   147  	defer a.mu.Unlock()
   148  	for _, value := range values {
   149  		index, cmp := a.binSearch(value, false)
   150  		if a.unique && cmp == 0 {
   151  			continue
   152  		}
   153  		if index < 0 {
   154  			a.array = append(a.array, value)
   155  			continue
   156  		}
   157  		if cmp > 0 {
   158  			index++
   159  		}
   160  		a.array = append(a.array[:index], append([]interface{}{value}, a.array[index:]...)...)
   161  	}
   162  	return a
   163  }
   164  
   165  // Get returns the value by the specified index.
   166  // If the given `index` is out of range of the array, the `found` is false.
   167  func (a *SortedArray) Get(index int) (value interface{}, found bool) {
   168  	a.mu.RLock()
   169  	defer a.mu.RUnlock()
   170  	if index < 0 || index >= len(a.array) {
   171  		return nil, false
   172  	}
   173  	return a.array[index], true
   174  }
   175  
   176  // Remove removes an item by index.
   177  // If the given `index` is out of range of the array, the `found` is false.
   178  func (a *SortedArray) Remove(index int) (value interface{}, found bool) {
   179  	a.mu.Lock()
   180  	defer a.mu.Unlock()
   181  	return a.doRemoveWithoutLock(index)
   182  }
   183  
   184  // doRemoveWithoutLock removes an item by index without lock.
   185  func (a *SortedArray) doRemoveWithoutLock(index int) (value interface{}, found bool) {
   186  	if index < 0 || index >= len(a.array) {
   187  		return nil, false
   188  	}
   189  	// Determine array boundaries when deleting to improve deletion efficiency.
   190  	if index == 0 {
   191  		value := a.array[0]
   192  		a.array = a.array[1:]
   193  		return value, true
   194  	} else if index == len(a.array)-1 {
   195  		value := a.array[index]
   196  		a.array = a.array[:index]
   197  		return value, true
   198  	}
   199  	// If it is a non-boundary delete,
   200  	// it will involve the creation of an array,
   201  	// then the deletion is less efficient.
   202  	value = a.array[index]
   203  	a.array = append(a.array[:index], a.array[index+1:]...)
   204  	return value, true
   205  }
   206  
   207  // RemoveValue removes an item by value.
   208  // It returns true if value is found in the array, or else false if not found.
   209  func (a *SortedArray) RemoveValue(value interface{}) bool {
   210  	a.mu.Lock()
   211  	defer a.mu.Unlock()
   212  	if i, r := a.binSearch(value, false); r == 0 {
   213  		_, res := a.doRemoveWithoutLock(i)
   214  		return res
   215  	}
   216  	return false
   217  }
   218  
   219  // RemoveValues removes an item by `values`.
   220  func (a *SortedArray) RemoveValues(values ...interface{}) {
   221  	a.mu.Lock()
   222  	defer a.mu.Unlock()
   223  	for _, value := range values {
   224  		if i, r := a.binSearch(value, false); r == 0 {
   225  			a.doRemoveWithoutLock(i)
   226  		}
   227  	}
   228  }
   229  
   230  // PopLeft pops and returns an item from the beginning of array.
   231  // Note that if the array is empty, the `found` is false.
   232  func (a *SortedArray) PopLeft() (value interface{}, found bool) {
   233  	a.mu.Lock()
   234  	defer a.mu.Unlock()
   235  	if len(a.array) == 0 {
   236  		return nil, false
   237  	}
   238  	value = a.array[0]
   239  	a.array = a.array[1:]
   240  	return value, true
   241  }
   242  
   243  // PopRight pops and returns an item from the end of array.
   244  // Note that if the array is empty, the `found` is false.
   245  func (a *SortedArray) PopRight() (value interface{}, found bool) {
   246  	a.mu.Lock()
   247  	defer a.mu.Unlock()
   248  	index := len(a.array) - 1
   249  	if index < 0 {
   250  		return nil, false
   251  	}
   252  	value = a.array[index]
   253  	a.array = a.array[:index]
   254  	return value, true
   255  }
   256  
   257  // PopRand randomly pops and return an item out of array.
   258  // Note that if the array is empty, the `found` is false.
   259  func (a *SortedArray) PopRand() (value interface{}, found bool) {
   260  	a.mu.Lock()
   261  	defer a.mu.Unlock()
   262  	return a.doRemoveWithoutLock(grand.Intn(len(a.array)))
   263  }
   264  
   265  // PopRands randomly pops and returns `size` items out of array.
   266  func (a *SortedArray) PopRands(size int) []interface{} {
   267  	a.mu.Lock()
   268  	defer a.mu.Unlock()
   269  	if size <= 0 || len(a.array) == 0 {
   270  		return nil
   271  	}
   272  	if size >= len(a.array) {
   273  		size = len(a.array)
   274  	}
   275  	array := make([]interface{}, size)
   276  	for i := 0; i < size; i++ {
   277  		array[i], _ = a.doRemoveWithoutLock(grand.Intn(len(a.array)))
   278  	}
   279  	return array
   280  }
   281  
   282  // PopLefts pops and returns `size` items from the beginning of array.
   283  func (a *SortedArray) PopLefts(size int) []interface{} {
   284  	a.mu.Lock()
   285  	defer a.mu.Unlock()
   286  	if size <= 0 || len(a.array) == 0 {
   287  		return nil
   288  	}
   289  	if size >= len(a.array) {
   290  		array := a.array
   291  		a.array = a.array[:0]
   292  		return array
   293  	}
   294  	value := a.array[0:size]
   295  	a.array = a.array[size:]
   296  	return value
   297  }
   298  
   299  // PopRights pops and returns `size` items from the end of array.
   300  func (a *SortedArray) PopRights(size int) []interface{} {
   301  	a.mu.Lock()
   302  	defer a.mu.Unlock()
   303  	if size <= 0 || len(a.array) == 0 {
   304  		return nil
   305  	}
   306  	index := len(a.array) - size
   307  	if index <= 0 {
   308  		array := a.array
   309  		a.array = a.array[:0]
   310  		return array
   311  	}
   312  	value := a.array[index:]
   313  	a.array = a.array[:index]
   314  	return value
   315  }
   316  
   317  // Range picks and returns items by range, like array[start:end].
   318  // Notice, if in concurrent-safe usage, it returns a copy of slice;
   319  // else a pointer to the underlying data.
   320  //
   321  // If `end` is negative, then the offset will start from the end of array.
   322  // If `end` is omitted, then the sequence will have everything from start up
   323  // until the end of the array.
   324  func (a *SortedArray) Range(start int, end ...int) []interface{} {
   325  	a.mu.RLock()
   326  	defer a.mu.RUnlock()
   327  	offsetEnd := len(a.array)
   328  	if len(end) > 0 && end[0] < offsetEnd {
   329  		offsetEnd = end[0]
   330  	}
   331  	if start > offsetEnd {
   332  		return nil
   333  	}
   334  	if start < 0 {
   335  		start = 0
   336  	}
   337  	array := ([]interface{})(nil)
   338  	if a.mu.IsSafe() {
   339  		array = make([]interface{}, offsetEnd-start)
   340  		copy(array, a.array[start:offsetEnd])
   341  	} else {
   342  		array = a.array[start:offsetEnd]
   343  	}
   344  	return array
   345  }
   346  
   347  // SubSlice returns a slice of elements from the array as specified
   348  // by the `offset` and `size` parameters.
   349  // If in concurrent safe usage, it returns a copy of the slice; else a pointer.
   350  //
   351  // If offset is non-negative, the sequence will start at that offset in the array.
   352  // If offset is negative, the sequence will start that far from the end of the array.
   353  //
   354  // If length is given and is positive, then the sequence will have up to that many elements in it.
   355  // If the array is shorter than the length, then only the available array elements will be present.
   356  // If length is given and is negative then the sequence will stop that many elements from the end of the array.
   357  // If it is omitted, then the sequence will have everything from offset up until the end of the array.
   358  //
   359  // Any possibility crossing the left border of array, it will fail.
   360  func (a *SortedArray) SubSlice(offset int, length ...int) []interface{} {
   361  	a.mu.RLock()
   362  	defer a.mu.RUnlock()
   363  	size := len(a.array)
   364  	if len(length) > 0 {
   365  		size = length[0]
   366  	}
   367  	if offset > len(a.array) {
   368  		return nil
   369  	}
   370  	if offset < 0 {
   371  		offset = len(a.array) + offset
   372  		if offset < 0 {
   373  			return nil
   374  		}
   375  	}
   376  	if size < 0 {
   377  		offset += size
   378  		size = -size
   379  		if offset < 0 {
   380  			return nil
   381  		}
   382  	}
   383  	end := offset + size
   384  	if end > len(a.array) {
   385  		end = len(a.array)
   386  		size = len(a.array) - offset
   387  	}
   388  	if a.mu.IsSafe() {
   389  		s := make([]interface{}, size)
   390  		copy(s, a.array[offset:])
   391  		return s
   392  	} else {
   393  		return a.array[offset:end]
   394  	}
   395  }
   396  
   397  // Sum returns the sum of values in an array.
   398  func (a *SortedArray) Sum() (sum int) {
   399  	a.mu.RLock()
   400  	defer a.mu.RUnlock()
   401  	for _, v := range a.array {
   402  		sum += gconv.Int(v)
   403  	}
   404  	return
   405  }
   406  
   407  // Len returns the length of array.
   408  func (a *SortedArray) Len() int {
   409  	a.mu.RLock()
   410  	length := len(a.array)
   411  	a.mu.RUnlock()
   412  	return length
   413  }
   414  
   415  // Slice returns the underlying data of array.
   416  // Note that, if it's in concurrent-safe usage, it returns a copy of underlying data,
   417  // or else a pointer to the underlying data.
   418  func (a *SortedArray) Slice() []interface{} {
   419  	var array []interface{}
   420  	if a.mu.IsSafe() {
   421  		a.mu.RLock()
   422  		defer a.mu.RUnlock()
   423  		array = make([]interface{}, len(a.array))
   424  		copy(array, a.array)
   425  	} else {
   426  		array = a.array
   427  	}
   428  	return array
   429  }
   430  
   431  // Interfaces returns current array as []interface{}.
   432  func (a *SortedArray) Interfaces() []interface{} {
   433  	return a.Slice()
   434  }
   435  
   436  // Contains checks whether a value exists in the array.
   437  func (a *SortedArray) Contains(value interface{}) bool {
   438  	return a.Search(value) != -1
   439  }
   440  
   441  // Search searches array by `value`, returns the index of `value`,
   442  // or returns -1 if not exists.
   443  func (a *SortedArray) Search(value interface{}) (index int) {
   444  	if i, r := a.binSearch(value, true); r == 0 {
   445  		return i
   446  	}
   447  	return -1
   448  }
   449  
   450  // Binary search.
   451  // It returns the last compared index and the result.
   452  // If `result` equals to 0, it means the value at `index` is equals to `value`.
   453  // If `result` lesser than 0, it means the value at `index` is lesser than `value`.
   454  // If `result` greater than 0, it means the value at `index` is greater than `value`.
   455  func (a *SortedArray) binSearch(value interface{}, lock bool) (index int, result int) {
   456  	if lock {
   457  		a.mu.RLock()
   458  		defer a.mu.RUnlock()
   459  	}
   460  	if len(a.array) == 0 {
   461  		return -1, -2
   462  	}
   463  	min := 0
   464  	max := len(a.array) - 1
   465  	mid := 0
   466  	cmp := -2
   467  	for min <= max {
   468  		mid = min + (max-min)/2
   469  		cmp = a.getComparator()(value, a.array[mid])
   470  		switch {
   471  		case cmp < 0:
   472  			max = mid - 1
   473  		case cmp > 0:
   474  			min = mid + 1
   475  		default:
   476  			return mid, cmp
   477  		}
   478  	}
   479  	return mid, cmp
   480  }
   481  
   482  // SetUnique sets unique mark to the array,
   483  // which means it does not contain any repeated items.
   484  // It also does unique check, remove all repeated items.
   485  func (a *SortedArray) SetUnique(unique bool) *SortedArray {
   486  	oldUnique := a.unique
   487  	a.unique = unique
   488  	if unique && oldUnique != unique {
   489  		a.Unique()
   490  	}
   491  	return a
   492  }
   493  
   494  // Unique uniques the array, clear repeated items.
   495  func (a *SortedArray) Unique() *SortedArray {
   496  	a.mu.Lock()
   497  	defer a.mu.Unlock()
   498  	if len(a.array) == 0 {
   499  		return a
   500  	}
   501  	i := 0
   502  	for {
   503  		if i == len(a.array)-1 {
   504  			break
   505  		}
   506  		if a.getComparator()(a.array[i], a.array[i+1]) == 0 {
   507  			a.array = append(a.array[:i+1], a.array[i+1+1:]...)
   508  		} else {
   509  			i++
   510  		}
   511  	}
   512  	return a
   513  }
   514  
   515  // Clone returns a new array, which is a copy of current array.
   516  func (a *SortedArray) Clone() (newArray *SortedArray) {
   517  	a.mu.RLock()
   518  	array := make([]interface{}, len(a.array))
   519  	copy(array, a.array)
   520  	a.mu.RUnlock()
   521  	return NewSortedArrayFrom(array, a.comparator, a.mu.IsSafe())
   522  }
   523  
   524  // Clear deletes all items of current array.
   525  func (a *SortedArray) Clear() *SortedArray {
   526  	a.mu.Lock()
   527  	if len(a.array) > 0 {
   528  		a.array = make([]interface{}, 0)
   529  	}
   530  	a.mu.Unlock()
   531  	return a
   532  }
   533  
   534  // LockFunc locks writing by callback function `f`.
   535  func (a *SortedArray) LockFunc(f func(array []interface{})) *SortedArray {
   536  	a.mu.Lock()
   537  	defer a.mu.Unlock()
   538  
   539  	// Keep the array always sorted.
   540  	defer sort.Slice(a.array, func(i, j int) bool {
   541  		return a.getComparator()(a.array[i], a.array[j]) < 0
   542  	})
   543  
   544  	f(a.array)
   545  	return a
   546  }
   547  
   548  // RLockFunc locks reading by callback function `f`.
   549  func (a *SortedArray) RLockFunc(f func(array []interface{})) *SortedArray {
   550  	a.mu.RLock()
   551  	defer a.mu.RUnlock()
   552  	f(a.array)
   553  	return a
   554  }
   555  
   556  // Merge merges `array` into current array.
   557  // The parameter `array` can be any garray or slice type.
   558  // The difference between Merge and Append is Append supports only specified slice type,
   559  // but Merge supports more parameter types.
   560  func (a *SortedArray) Merge(array interface{}) *SortedArray {
   561  	return a.Add(gconv.Interfaces(array)...)
   562  }
   563  
   564  // Chunk splits an array into multiple arrays,
   565  // the size of each array is determined by `size`.
   566  // The last chunk may contain less than size elements.
   567  func (a *SortedArray) Chunk(size int) [][]interface{} {
   568  	if size < 1 {
   569  		return nil
   570  	}
   571  	a.mu.RLock()
   572  	defer a.mu.RUnlock()
   573  	length := len(a.array)
   574  	chunks := int(math.Ceil(float64(length) / float64(size)))
   575  	var n [][]interface{}
   576  	for i, end := 0, 0; chunks > 0; chunks-- {
   577  		end = (i + 1) * size
   578  		if end > length {
   579  			end = length
   580  		}
   581  		n = append(n, a.array[i*size:end])
   582  		i++
   583  	}
   584  	return n
   585  }
   586  
   587  // Rand randomly returns one item from array(no deleting).
   588  func (a *SortedArray) Rand() (value interface{}, found bool) {
   589  	a.mu.RLock()
   590  	defer a.mu.RUnlock()
   591  	if len(a.array) == 0 {
   592  		return nil, false
   593  	}
   594  	return a.array[grand.Intn(len(a.array))], true
   595  }
   596  
   597  // Rands randomly returns `size` items from array(no deleting).
   598  func (a *SortedArray) Rands(size int) []interface{} {
   599  	a.mu.RLock()
   600  	defer a.mu.RUnlock()
   601  	if size <= 0 || len(a.array) == 0 {
   602  		return nil
   603  	}
   604  	array := make([]interface{}, size)
   605  	for i := 0; i < size; i++ {
   606  		array[i] = a.array[grand.Intn(len(a.array))]
   607  	}
   608  	return array
   609  }
   610  
   611  // Join joins array elements with a string `glue`.
   612  func (a *SortedArray) Join(glue string) string {
   613  	a.mu.RLock()
   614  	defer a.mu.RUnlock()
   615  	if len(a.array) == 0 {
   616  		return ""
   617  	}
   618  	buffer := bytes.NewBuffer(nil)
   619  	for k, v := range a.array {
   620  		buffer.WriteString(gconv.String(v))
   621  		if k != len(a.array)-1 {
   622  			buffer.WriteString(glue)
   623  		}
   624  	}
   625  	return buffer.String()
   626  }
   627  
   628  // CountValues counts the number of occurrences of all values in the array.
   629  func (a *SortedArray) CountValues() map[interface{}]int {
   630  	m := make(map[interface{}]int)
   631  	a.mu.RLock()
   632  	defer a.mu.RUnlock()
   633  	for _, v := range a.array {
   634  		m[v]++
   635  	}
   636  	return m
   637  }
   638  
   639  // Iterator is alias of IteratorAsc.
   640  func (a *SortedArray) Iterator(f func(k int, v interface{}) bool) {
   641  	a.IteratorAsc(f)
   642  }
   643  
   644  // IteratorAsc iterates the array readonly in ascending order with given callback function `f`.
   645  // If `f` returns true, then it continues iterating; or false to stop.
   646  func (a *SortedArray) IteratorAsc(f func(k int, v interface{}) bool) {
   647  	a.mu.RLock()
   648  	defer a.mu.RUnlock()
   649  	for k, v := range a.array {
   650  		if !f(k, v) {
   651  			break
   652  		}
   653  	}
   654  }
   655  
   656  // IteratorDesc iterates the array readonly in descending order with given callback function `f`.
   657  // If `f` returns true, then it continues iterating; or false to stop.
   658  func (a *SortedArray) IteratorDesc(f func(k int, v interface{}) bool) {
   659  	a.mu.RLock()
   660  	defer a.mu.RUnlock()
   661  	for i := len(a.array) - 1; i >= 0; i-- {
   662  		if !f(i, a.array[i]) {
   663  			break
   664  		}
   665  	}
   666  }
   667  
   668  // String returns current array as a string, which implements like json.Marshal does.
   669  func (a *SortedArray) String() string {
   670  	if a == nil {
   671  		return ""
   672  	}
   673  	a.mu.RLock()
   674  	defer a.mu.RUnlock()
   675  	buffer := bytes.NewBuffer(nil)
   676  	buffer.WriteByte('[')
   677  	s := ""
   678  	for k, v := range a.array {
   679  		s = gconv.String(v)
   680  		if gstr.IsNumeric(s) {
   681  			buffer.WriteString(s)
   682  		} else {
   683  			buffer.WriteString(`"` + gstr.QuoteMeta(s, `"\`) + `"`)
   684  		}
   685  		if k != len(a.array)-1 {
   686  			buffer.WriteByte(',')
   687  		}
   688  	}
   689  	buffer.WriteByte(']')
   690  	return buffer.String()
   691  }
   692  
   693  // MarshalJSON implements the interface MarshalJSON for json.Marshal.
   694  // Note that do not use pointer as its receiver here.
   695  func (a SortedArray) MarshalJSON() ([]byte, error) {
   696  	a.mu.RLock()
   697  	defer a.mu.RUnlock()
   698  	return json.Marshal(a.array)
   699  }
   700  
   701  // UnmarshalJSON implements the interface UnmarshalJSON for json.Unmarshal.
   702  // Note that the comparator is set as string comparator in default.
   703  func (a *SortedArray) UnmarshalJSON(b []byte) error {
   704  	if a.comparator == nil {
   705  		a.array = make([]interface{}, 0)
   706  		a.comparator = gutil.ComparatorString
   707  	}
   708  	a.mu.Lock()
   709  	defer a.mu.Unlock()
   710  	if err := json.UnmarshalUseNumber(b, &a.array); err != nil {
   711  		return err
   712  	}
   713  	if a.comparator != nil && a.array != nil {
   714  		sort.Slice(a.array, func(i, j int) bool {
   715  			return a.comparator(a.array[i], a.array[j]) < 0
   716  		})
   717  	}
   718  	return nil
   719  }
   720  
   721  // UnmarshalValue is an interface implement which sets any type of value for array.
   722  // Note that the comparator is set as string comparator in default.
   723  func (a *SortedArray) UnmarshalValue(value interface{}) (err error) {
   724  	if a.comparator == nil {
   725  		a.comparator = gutil.ComparatorString
   726  	}
   727  	a.mu.Lock()
   728  	defer a.mu.Unlock()
   729  	switch value.(type) {
   730  	case string, []byte:
   731  		err = json.UnmarshalUseNumber(gconv.Bytes(value), &a.array)
   732  	default:
   733  		a.array = gconv.SliceAny(value)
   734  	}
   735  	if a.comparator != nil && a.array != nil {
   736  		sort.Slice(a.array, func(i, j int) bool {
   737  			return a.comparator(a.array[i], a.array[j]) < 0
   738  		})
   739  	}
   740  	return err
   741  }
   742  
   743  // FilterNil removes all nil value of the array.
   744  func (a *SortedArray) FilterNil() *SortedArray {
   745  	a.mu.Lock()
   746  	defer a.mu.Unlock()
   747  	for i := 0; i < len(a.array); {
   748  		if empty.IsNil(a.array[i]) {
   749  			a.array = append(a.array[:i], a.array[i+1:]...)
   750  		} else {
   751  			break
   752  		}
   753  	}
   754  	for i := len(a.array) - 1; i >= 0; {
   755  		if empty.IsNil(a.array[i]) {
   756  			a.array = append(a.array[:i], a.array[i+1:]...)
   757  		} else {
   758  			break
   759  		}
   760  	}
   761  	return a
   762  }
   763  
   764  // Filter iterates array and filters elements using custom callback function.
   765  // It removes the element from array if callback function `filter` returns true,
   766  // it or else does nothing and continues iterating.
   767  func (a *SortedArray) Filter(filter func(index int, value interface{}) bool) *SortedArray {
   768  	a.mu.Lock()
   769  	defer a.mu.Unlock()
   770  	for i := 0; i < len(a.array); {
   771  		if filter(i, a.array[i]) {
   772  			a.array = append(a.array[:i], a.array[i+1:]...)
   773  		} else {
   774  			i++
   775  		}
   776  	}
   777  	return a
   778  }
   779  
   780  // FilterEmpty removes all empty value of the array.
   781  // Values like: 0, nil, false, "", len(slice/map/chan) == 0 are considered empty.
   782  func (a *SortedArray) FilterEmpty() *SortedArray {
   783  	a.mu.Lock()
   784  	defer a.mu.Unlock()
   785  	for i := 0; i < len(a.array); {
   786  		if empty.IsEmpty(a.array[i]) {
   787  			a.array = append(a.array[:i], a.array[i+1:]...)
   788  		} else {
   789  			break
   790  		}
   791  	}
   792  	for i := len(a.array) - 1; i >= 0; {
   793  		if empty.IsEmpty(a.array[i]) {
   794  			a.array = append(a.array[:i], a.array[i+1:]...)
   795  		} else {
   796  			break
   797  		}
   798  	}
   799  	return a
   800  }
   801  
   802  // Walk applies a user supplied function `f` to every item of array.
   803  func (a *SortedArray) Walk(f func(value interface{}) interface{}) *SortedArray {
   804  	a.mu.Lock()
   805  	defer a.mu.Unlock()
   806  	// Keep the array always sorted.
   807  	defer sort.Slice(a.array, func(i, j int) bool {
   808  		return a.getComparator()(a.array[i], a.array[j]) < 0
   809  	})
   810  	for i, v := range a.array {
   811  		a.array[i] = f(v)
   812  	}
   813  	return a
   814  }
   815  
   816  // IsEmpty checks whether the array is empty.
   817  func (a *SortedArray) IsEmpty() bool {
   818  	return a.Len() == 0
   819  }
   820  
   821  // getComparator returns the comparator if it's previously set,
   822  // or else it panics.
   823  func (a *SortedArray) getComparator() func(a, b interface{}) int {
   824  	if a.comparator == nil {
   825  		panic("comparator is missing for sorted array")
   826  	}
   827  	return a.comparator
   828  }
   829  
   830  // DeepCopy implements interface for deep copy of current type.
   831  func (a *SortedArray) DeepCopy() interface{} {
   832  	if a == nil {
   833  		return nil
   834  	}
   835  	a.mu.RLock()
   836  	defer a.mu.RUnlock()
   837  	newSlice := make([]interface{}, len(a.array))
   838  	for i, v := range a.array {
   839  		newSlice[i] = deepcopy.Copy(v)
   840  	}
   841  	return NewSortedArrayFrom(newSlice, a.comparator, a.mu.IsSafe())
   842  }