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| -rw-r--r-- | public/common/util.js | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/public/common/util.js b/public/common/util.js new file mode 100644 index 0000000..dd9e3ec --- /dev/null +++ b/public/common/util.js @@ -0,0 +1,174 @@ +// === COMMON LIBRARY === + +function random(range) { + // An MLCG using integer arithmetic with doubles. + // https://www.ams.org/journals/mcom/1999-68-225/S0025-5718-99-00996-5/S0025-5718-99-00996-5.pdf + // m = 2**35 − 31 + return (game.seed = game.seed * 200105 % 34359738337) % range +} + +function random_bigint(range) { + // Largest MLCG that will fit its state in a double. + // Uses BigInt for arithmetic, so is an order of magnitude slower. + // https://www.ams.org/journals/mcom/1999-68-225/S0025-5718-99-00996-5/S0025-5718-99-00996-5.pdf + // m = 2**53 - 111 + return (game.seed = Number(BigInt(game.seed) * 5667072534355537n % 9007199254740881n)) % range +} + +function shuffle(list) { + for (let i = list.length - 1; i > 0; --i) { + let j = random(i + 1) + let tmp = list[j] + list[j] = list[i] + list[i] = tmp + } +} + +function shuffle_bigint(list) { + for (let i = list.length - 1; i > 0; --i) { + let j = random_bigint(i + 1) + let tmp = list[j] + list[j] = list[i] + list[i] = tmp + } +} + +// remove item at index (faster than splice) +function array_remove(array, index) { + let n = array.length + for (let i = index + 1; i < n; ++i) + array[i - 1] = array[i] + array.length = n - 1 + return array +} + +// insert item at index (faster than splice) +function array_insert(array, index, item) { + for (let i = array.length; i > index; --i) + array[i] = array[i - 1] + array[index] = item + return array +} + +function set_clear(set) { + set.length = 0 +} + +function set_has(set, item) { + let a = 0 + let b = set.length - 1 + while (a <= b) { + let m = (a + b) >> 1 + let x = set[m] + if (item < x) + b = m - 1 + else if (item > x) + a = m + 1 + else + return true + } + return false +} + +function set_add(set, item) { + let a = 0 + let b = set.length - 1 + while (a <= b) { + let m = (a + b) >> 1 + let x = set[m] + if (item < x) + b = m - 1 + else if (item > x) + a = m + 1 + else + return set + } + return array_insert(set, a, item) +} + +function set_delete(set, item) { + let a = 0 + let b = set.length - 1 + while (a <= b) { + let m = (a + b) >> 1 + let x = set[m] + if (item < x) + b = m - 1 + else if (item > x) + a = m + 1 + else + return array_remove(set, m) + } + return set +} + +function set_toggle(set, item) { + let a = 0 + let b = set.length - 1 + while (a <= b) { + let m = (a + b) >> 1 + let x = set[m] + if (item < x) + b = m - 1 + else if (item > x) + a = m + 1 + else + return array_remove(set, m) + } + return array_insert(set, a, item) +} + +// Fast deep copy for objects without cycles +function object_copy(original) { + if (Array.isArray(original)) { + let n = original.length + let copy = new Array(n) + for (let i = 0; i < n; ++i) { + let v = original[i] + if (typeof v === "object" && v !== null) + copy[i] = object_copy(v) + else + copy[i] = v + } + return copy + } else { + let copy = {} + for (let i in original) { + let v = original[i] + if (typeof v === "object" && v !== null) + copy[i] = object_copy(v) + else + copy[i] = v + } + return copy + } +} + +function clear_undo() { + if (game.undo.length > 0) + game.undo = [] +} + +function push_undo() { + let copy = {} + for (let k in game) { + let v = game[k] + if (k === "undo") + continue + else if (k === "log") + v = v.length + else if (typeof v === "object" && v !== null) + v = object_copy(v) + copy[k] = v + } + game.undo.push(copy) +} + +function pop_undo() { + let save_log = game.log + let save_undo = game.undo + game = save_undo.pop() + save_log.length = game.log + game.log = save_log + game.undo = save_undo +} |