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2 | 2 | //! © 2017 Angry Bytes and contributors. MIT licensed.
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3 | 3 |
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4 | 4 | (function (global, factory) {
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5 |
| - typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() : |
6 |
| - typeof define === 'function' && define.amd ? define(factory) : |
7 |
| - (global.stable = factory()); |
| 5 | + typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() : |
| 6 | + typeof define === 'function' && define.amd ? define(factory) : |
| 7 | + (global.stable = factory()); |
8 | 8 | }(this, (function () { 'use strict';
|
9 | 9 |
|
10 |
| -// A stable array sort, because `Array#sort()` is not guaranteed stable. |
11 |
| -// This is an implementation of merge sort, without recursion. |
| 10 | + // A stable array sort, because `Array#sort()` is not guaranteed stable. |
| 11 | + // This is an implementation of merge sort, without recursion. |
12 | 12 |
|
13 |
| -var stable = function(arr, comp) { |
14 |
| - return exec(arr.slice(), comp); |
15 |
| -}; |
| 13 | + var stable = function(arr, comp) { |
| 14 | + return exec(arr.slice(), comp); |
| 15 | + }; |
16 | 16 |
|
17 |
| -stable.inplace = function(arr, comp) { |
18 |
| - var result = exec(arr, comp); |
| 17 | + stable.inplace = function(arr, comp) { |
| 18 | + var result = exec(arr, comp); |
19 | 19 |
|
20 |
| - // This simply copies back if the result isn't in the original array, |
21 |
| - // which happens on an odd number of passes. |
22 |
| - if (result !== arr) { |
23 |
| - pass(result, null, arr.length, arr); |
24 |
| - } |
| 20 | + // This simply copies back if the result isn't in the original array, |
| 21 | + // which happens on an odd number of passes. |
| 22 | + if (result !== arr) { |
| 23 | + pass(result, null, arr.length, arr); |
| 24 | + } |
25 | 25 |
|
26 |
| - return arr; |
27 |
| -}; |
| 26 | + return arr; |
| 27 | + }; |
| 28 | + |
| 29 | + // Execute the sort using the input array and a second buffer as work space. |
| 30 | + // Returns one of those two, containing the final result. |
| 31 | + function exec(arr, comp) { |
| 32 | + if (typeof(comp) !== 'function') { |
| 33 | + comp = function(a, b) { |
| 34 | + return String(a).localeCompare(b); |
| 35 | + }; |
| 36 | + } |
28 | 37 |
|
29 |
| -// Execute the sort using the input array and a second buffer as work space. |
30 |
| -// Returns one of those two, containing the final result. |
31 |
| -function exec(arr, comp) { |
32 |
| - if (typeof(comp) !== 'function') { |
33 |
| - comp = function(a, b) { |
34 |
| - return String(a).localeCompare(b); |
35 |
| - }; |
36 |
| - } |
| 38 | + // Short-circuit when there's nothing to sort. |
| 39 | + var len = arr.length; |
| 40 | + if (len <= 1) { |
| 41 | + return arr; |
| 42 | + } |
37 | 43 |
|
38 |
| - // Short-circuit when there's nothing to sort. |
39 |
| - var len = arr.length; |
40 |
| - if (len <= 1) { |
41 |
| - return arr; |
42 |
| - } |
| 44 | + // Rather than dividing input, simply iterate chunks of 1, 2, 4, 8, etc. |
| 45 | + // Chunks are the size of the left or right hand in merge sort. |
| 46 | + // Stop when the left-hand covers all of the array. |
| 47 | + var buffer = new Array(len); |
| 48 | + for (var chk = 1; chk < len; chk *= 2) { |
| 49 | + pass(arr, comp, chk, buffer); |
43 | 50 |
|
44 |
| - // Rather than dividing input, simply iterate chunks of 1, 2, 4, 8, etc. |
45 |
| - // Chunks are the size of the left or right hand in merge sort. |
46 |
| - // Stop when the left-hand covers all of the array. |
47 |
| - var buffer = new Array(len); |
48 |
| - for (var chk = 1; chk < len; chk *= 2) { |
49 |
| - pass(arr, comp, chk, buffer); |
| 51 | + var tmp = arr; |
| 52 | + arr = buffer; |
| 53 | + buffer = tmp; |
| 54 | + } |
50 | 55 |
|
51 |
| - var tmp = arr; |
52 |
| - arr = buffer; |
53 |
| - buffer = tmp; |
| 56 | + return arr; |
54 | 57 | }
|
55 | 58 |
|
56 |
| - return arr; |
57 |
| -} |
58 |
| - |
59 |
| -// Run a single pass with the given chunk size. |
60 |
| -var pass = function(arr, comp, chk, result) { |
61 |
| - var len = arr.length; |
62 |
| - var i = 0; |
63 |
| - // Step size / double chunk size. |
64 |
| - var dbl = chk * 2; |
65 |
| - // Bounds of the left and right chunks. |
66 |
| - var l, r, e; |
67 |
| - // Iterators over the left and right chunk. |
68 |
| - var li, ri; |
69 |
| - |
70 |
| - // Iterate over pairs of chunks. |
71 |
| - for (l = 0; l < len; l += dbl) { |
72 |
| - r = l + chk; |
73 |
| - e = r + chk; |
74 |
| - if (r > len) r = len; |
75 |
| - if (e > len) e = len; |
76 |
| - |
77 |
| - // Iterate both chunks in parallel. |
78 |
| - li = l; |
79 |
| - ri = r; |
80 |
| - while (true) { |
81 |
| - // Compare the chunks. |
82 |
| - if (li < r && ri < e) { |
83 |
| - // This works for a regular `sort()` compatible comparator, |
84 |
| - // but also for a simple comparator like: `a > b` |
85 |
| - if (comp(arr[li], arr[ri]) <= 0) { |
| 59 | + // Run a single pass with the given chunk size. |
| 60 | + var pass = function(arr, comp, chk, result) { |
| 61 | + var len = arr.length; |
| 62 | + var i = 0; |
| 63 | + // Step size / double chunk size. |
| 64 | + var dbl = chk * 2; |
| 65 | + // Bounds of the left and right chunks. |
| 66 | + var l, r, e; |
| 67 | + // Iterators over the left and right chunk. |
| 68 | + var li, ri; |
| 69 | + |
| 70 | + // Iterate over pairs of chunks. |
| 71 | + for (l = 0; l < len; l += dbl) { |
| 72 | + r = l + chk; |
| 73 | + e = r + chk; |
| 74 | + if (r > len) r = len; |
| 75 | + if (e > len) e = len; |
| 76 | + |
| 77 | + // Iterate both chunks in parallel. |
| 78 | + li = l; |
| 79 | + ri = r; |
| 80 | + while (true) { |
| 81 | + // Compare the chunks. |
| 82 | + if (li < r && ri < e) { |
| 83 | + // This works for a regular `sort()` compatible comparator, |
| 84 | + // but also for a simple comparator like: `a > b` |
| 85 | + if (comp(arr[li], arr[ri]) <= 0) { |
| 86 | + result[i++] = arr[li++]; |
| 87 | + } |
| 88 | + else { |
| 89 | + result[i++] = arr[ri++]; |
| 90 | + } |
| 91 | + } |
| 92 | + // Nothing to compare, just flush what's left. |
| 93 | + else if (li < r) { |
86 | 94 | result[i++] = arr[li++];
|
87 | 95 | }
|
88 |
| - else { |
| 96 | + else if (ri < e) { |
89 | 97 | result[i++] = arr[ri++];
|
90 | 98 | }
|
91 |
| - } |
92 |
| - // Nothing to compare, just flush what's left. |
93 |
| - else if (li < r) { |
94 |
| - result[i++] = arr[li++]; |
95 |
| - } |
96 |
| - else if (ri < e) { |
97 |
| - result[i++] = arr[ri++]; |
98 |
| - } |
99 |
| - // Both iterators are at the chunk ends. |
100 |
| - else { |
101 |
| - break; |
| 99 | + // Both iterators are at the chunk ends. |
| 100 | + else { |
| 101 | + break; |
| 102 | + } |
102 | 103 | }
|
103 | 104 | }
|
104 |
| - } |
105 |
| -}; |
| 105 | + }; |
106 | 106 |
|
107 |
| -return stable; |
| 107 | + return stable; |
108 | 108 |
|
109 | 109 | })));
|
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