length-truncate-with-indexed.js

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/*

 * Any copyright is dedicated to the Public Domain.

 * http://creativecommons.org/licenses/publicdomain/

 * Contributor:

 *   Jeff Walden <jwalden+code@mit.edu>

*/

//-----------------------------------------------------------------------------

var BUGNUMBER = 858381;

var summary =

  "Array length setting/truncating with non-dense, indexed elements";

print(BUGNUMBER + ": " + summary);

/**************

 * BEGIN TEST *

 **************/

function testTruncateDenseAndSparse()

  var arr;

  // initialized length 16, capacity same

  arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15];

  // plus a sparse element

  arr[987654321] = 987654321;

  // lop off the sparse element and half the dense elements, shrink capacity

  arr.length = 8;

  assertEq(987654321 in arr, false);

  assertEq(arr[987654321], undefined);

  assertEq(arr.length, 8);

testTruncateDenseAndSparse();

function testTruncateSparse()

  // initialized length 8, capacity same

  var arr = [0, 1, 2, 3, 4, 5, 6, 7];

  // plus a sparse element

  arr[987654321] = 987654321;

  // lop off the sparse element, leave initialized length/capacity unchanged

  arr.length = 8;

  assertEq(987654321 in arr, false);

  assertEq(arr[987654321], undefined);

  assertEq(arr.length, 8);

testTruncateSparse();

function testTruncateDenseAndSparseShrinkCapacity()

  // initialized length 11, capacity...somewhat larger, likely 16

  var arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

  // plus a sparse element

  arr[987654321] = 987654321;

  // lop off the sparse element, reduce initialized length, reduce capacity

  arr.length = 8;

  assertEq(987654321 in arr, false);

  assertEq(arr[987654321], undefined);

  assertEq(arr.length, 8);

testTruncateDenseAndSparseShrinkCapacity();

function testTruncateSparseShrinkCapacity()

  // initialized length 8, capacity same

  var arr = [0, 1, 2, 3, 4, 5, 6, 7];

  // capacity expands to accommodate, initialized length remains same (not equal

  // to capacity or length)

  arr[15] = 15;

  // now no elements past initialized length

  delete arr[15];

  // ...except a sparse element

  arr[987654321] = 987654321;

  // trims sparse element, doesn't change initialized length, shrinks capacity

  arr.length = 8;

  assertEq(987654321 in arr, false);

  assertEq(arr[987654321], undefined);

  assertEq(arr.length, 8);

testTruncateSparseShrinkCapacity();

/******************************************************************************/

if (typeof reportCompare === "function")

  reportCompare(true, true);

print("Tests complete");