nodejs/test/parallel/test-buffer-slice.js

// Copyright Joyent, Inc. and other Node contributors.
//
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// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
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// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

'use strict';

require('../common');
const assert = require('assert');

assert.strictEqual(Buffer.from('hello', 'utf8').slice(0, 0).length, 0);
assert.strictEqual(Buffer('hello', 'utf8').slice(0, 0).length, 0);

const buf = Buffer.from('0123456789', 'utf8');
const expectedSameBufs = [
  [buf.slice(-10, 10), Buffer.from('0123456789', 'utf8')],
  [buf.slice(-20, 10), Buffer.from('0123456789', 'utf8')],
  [buf.slice(-20, -10), Buffer.from('', 'utf8')],
  [buf.slice(), Buffer.from('0123456789', 'utf8')],
  [buf.slice(0), Buffer.from('0123456789', 'utf8')],
  [buf.slice(0, 0), Buffer.from('', 'utf8')],
  [buf.slice(undefined), Buffer.from('0123456789', 'utf8')],
  [buf.slice('foobar'), Buffer.from('0123456789', 'utf8')],
  [buf.slice(undefined, undefined), Buffer.from('0123456789', 'utf8')],
  [buf.slice(2), Buffer.from('23456789', 'utf8')],
  [buf.slice(5), Buffer.from('56789', 'utf8')],
  [buf.slice(10), Buffer.from('', 'utf8')],
  [buf.slice(5, 8), Buffer.from('567', 'utf8')],
  [buf.slice(8, -1), Buffer.from('8', 'utf8')],
  [buf.slice(-10), Buffer.from('0123456789', 'utf8')],
  [buf.slice(0, -9), Buffer.from('0', 'utf8')],
  [buf.slice(0, -10), Buffer.from('', 'utf8')],
  [buf.slice(0, -1), Buffer.from('012345678', 'utf8')],
  [buf.slice(2, -2), Buffer.from('234567', 'utf8')],
  [buf.slice(0, 65536), Buffer.from('0123456789', 'utf8')],
  [buf.slice(65536, 0), Buffer.from('', 'utf8')],
  [buf.slice(-5, -8), Buffer.from('', 'utf8')],
  [buf.slice(-5, -3), Buffer.from('56', 'utf8')],
  [buf.slice(-10, 10), Buffer.from('0123456789', 'utf8')],
  [buf.slice('0', '1'), Buffer.from('0', 'utf8')],
  [buf.slice('-5', '10'), Buffer.from('56789', 'utf8')],
  [buf.slice('-10', '10'), Buffer.from('0123456789', 'utf8')],
  [buf.slice('-10', '-5'), Buffer.from('01234', 'utf8')],
  [buf.slice('-10', '-0'), Buffer.from('', 'utf8')],
  [buf.slice('111'), Buffer.from('', 'utf8')],
  [buf.slice('0', '-111'), Buffer.from('', 'utf8')],
];

for (let i = 0, s = buf.toString(); i < buf.length; ++i) {
  expectedSameBufs.push(
    [buf.slice(i), Buffer.from(s.slice(i))],
    [buf.slice(0, i), Buffer.from(s.slice(0, i))],
    [buf.slice(-i), Buffer.from(s.slice(-i))],
    [buf.slice(0, -i), Buffer.from(s.slice(0, -i))]
  );
}

for (const [buf1, buf2] of expectedSameBufs) {
  assert.strictEqual(Buffer.compare(buf1, buf2), 0);
}

const utf16Buf = Buffer.from('0123456789', 'utf16le');
assert.deepStrictEqual(utf16Buf.slice(0, 6), Buffer.from('012', 'utf16le'));
// Try to slice a zero length Buffer.
// See https://github.com/joyent/node/issues/5881
assert.strictEqual(Buffer.alloc(0).slice(0, 1).length, 0);

{
  // Single argument slice
  assert.strictEqual(Buffer.from('abcde', 'utf8').slice(1).toString('utf8'),
                     'bcde');
}

// slice(0,0).length === 0
assert.strictEqual(Buffer.from('hello', 'utf8').slice(0, 0).length, 0);

{
  // Regression tests for https://github.com/nodejs/node/issues/9096
  const buf = Buffer.from('abcd', 'utf8');
  assert.strictEqual(buf.slice(buf.length / 3).toString('utf8'), 'bcd');
  assert.strictEqual(
    buf.slice(buf.length / 3, buf.length).toString(),
    'bcd'
  );
}

{
  const buf = Buffer.from('abcdefg', 'utf8');
  assert.strictEqual(buf.slice(-(-1 >>> 0) - 1).toString('utf8'),
                     buf.toString('utf8'));
}

{
  const buf = Buffer.from('abc', 'utf8');
  assert.strictEqual(buf.slice(-0.5).toString('utf8'), buf.toString('utf8'));
}

{
  const buf = Buffer.from([
    1, 29, 0, 0, 1, 143, 216, 162, 92, 254, 248, 63, 0,
    0, 0, 18, 184, 6, 0, 175, 29, 0, 8, 11, 1, 0, 0,
  ]);
  const chunk1 = Buffer.from([
    1, 29, 0, 0, 1, 143, 216, 162, 92, 254, 248, 63, 0,
  ]);
  const chunk2 = Buffer.from([
    0, 0, 18, 184, 6, 0, 175, 29, 0, 8, 11, 1, 0, 0,
  ]);
  const middle = buf.length / 2;

  assert.deepStrictEqual(buf.slice(0, middle), chunk1);
  assert.deepStrictEqual(buf.slice(middle), chunk2);
}