From 3c51c3be85bb0d1bdb87ea0d6632f1c256912f27 Mon Sep 17 00:00:00 2001 From: Dimitri Staessens Date: Sun, 6 Oct 2019 21:37:45 +0200 Subject: build: Add some required modules for node --- .../node_modules/source-map/lib/quick-sort.js | 114 +++++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100644 node_modules/autoprefixer/node_modules/source-map/lib/quick-sort.js (limited to 'node_modules/autoprefixer/node_modules/source-map/lib/quick-sort.js') diff --git a/node_modules/autoprefixer/node_modules/source-map/lib/quick-sort.js b/node_modules/autoprefixer/node_modules/source-map/lib/quick-sort.js new file mode 100644 index 0000000..6a7caad --- /dev/null +++ b/node_modules/autoprefixer/node_modules/source-map/lib/quick-sort.js @@ -0,0 +1,114 @@ +/* -*- Mode: js; js-indent-level: 2; -*- */ +/* + * Copyright 2011 Mozilla Foundation and contributors + * Licensed under the New BSD license. See LICENSE or: + * http://opensource.org/licenses/BSD-3-Clause + */ + +// It turns out that some (most?) JavaScript engines don't self-host +// `Array.prototype.sort`. This makes sense because C++ will likely remain +// faster than JS when doing raw CPU-intensive sorting. However, when using a +// custom comparator function, calling back and forth between the VM's C++ and +// JIT'd JS is rather slow *and* loses JIT type information, resulting in +// worse generated code for the comparator function than would be optimal. In +// fact, when sorting with a comparator, these costs outweigh the benefits of +// sorting in C++. By using our own JS-implemented Quick Sort (below), we get +// a ~3500ms mean speed-up in `bench/bench.html`. + +/** + * Swap the elements indexed by `x` and `y` in the array `ary`. + * + * @param {Array} ary + * The array. + * @param {Number} x + * The index of the first item. + * @param {Number} y + * The index of the second item. + */ +function swap(ary, x, y) { + var temp = ary[x]; + ary[x] = ary[y]; + ary[y] = temp; +} + +/** + * Returns a random integer within the range `low .. high` inclusive. + * + * @param {Number} low + * The lower bound on the range. + * @param {Number} high + * The upper bound on the range. + */ +function randomIntInRange(low, high) { + return Math.round(low + (Math.random() * (high - low))); +} + +/** + * The Quick Sort algorithm. + * + * @param {Array} ary + * An array to sort. + * @param {function} comparator + * Function to use to compare two items. + * @param {Number} p + * Start index of the array + * @param {Number} r + * End index of the array + */ +function doQuickSort(ary, comparator, p, r) { + // If our lower bound is less than our upper bound, we (1) partition the + // array into two pieces and (2) recurse on each half. If it is not, this is + // the empty array and our base case. + + if (p < r) { + // (1) Partitioning. + // + // The partitioning chooses a pivot between `p` and `r` and moves all + // elements that are less than or equal to the pivot to the before it, and + // all the elements that are greater than it after it. The effect is that + // once partition is done, the pivot is in the exact place it will be when + // the array is put in sorted order, and it will not need to be moved + // again. This runs in O(n) time. + + // Always choose a random pivot so that an input array which is reverse + // sorted does not cause O(n^2) running time. + var pivotIndex = randomIntInRange(p, r); + var i = p - 1; + + swap(ary, pivotIndex, r); + var pivot = ary[r]; + + // Immediately after `j` is incremented in this loop, the following hold + // true: + // + // * Every element in `ary[p .. i]` is less than or equal to the pivot. + // + // * Every element in `ary[i+1 .. j-1]` is greater than the pivot. + for (var j = p; j < r; j++) { + if (comparator(ary[j], pivot) <= 0) { + i += 1; + swap(ary, i, j); + } + } + + swap(ary, i + 1, j); + var q = i + 1; + + // (2) Recurse on each half. + + doQuickSort(ary, comparator, p, q - 1); + doQuickSort(ary, comparator, q + 1, r); + } +} + +/** + * Sort the given array in-place with the given comparator function. + * + * @param {Array} ary + * An array to sort. + * @param {function} comparator + * Function to use to compare two items. + */ +exports.quickSort = function (ary, comparator) { + doQuickSort(ary, comparator, 0, ary.length - 1); +}; -- cgit v1.2.3