node/test/parallel/test-readuint.js

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'use strict';
/*
 * A battery of tests to help us read a series of uints
 */

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

/*
 * We need to check the following things:
 *  - We are correctly resolving big endian (doesn't mean anything for 8 bit)
 *  - Correctly resolving little endian (doesn't mean anything for 8 bit)
 *  - Correctly using the offsets
 *  - Correctly interpreting values that are beyond the signed range as unsigned
 */
function test8(clazz) {
  const data = new clazz(4);

  data[0] = 23;
  data[1] = 23;
  data[2] = 23;
  data[3] = 23;
  assert.strictEqual(23, data.readUInt8(0));
  assert.strictEqual(23, data.readUInt8(1));
  assert.strictEqual(23, data.readUInt8(2));
  assert.strictEqual(23, data.readUInt8(3));

  data[0] = 255; /* If it became a signed int, would be -1 */
  assert.strictEqual(255, data.readUInt8(0));
}


/*
 * Test 16 bit unsigned integers. We need to verify the same set as 8 bit, only
 * now some of the issues actually matter:
 *  - We are correctly resolving big endian
 *  - Correctly resolving little endian
 *  - Correctly using the offsets
 *  - Correctly interpreting values that are beyond the signed range as unsigned
 */
function test16(clazz) {
  const data = new clazz(4);

  data[0] = 0;
  data[1] = 0x23;
  data[2] = 0x42;
  data[3] = 0x3f;
  assert.strictEqual(0x23, data.readUInt16BE(0));
  assert.strictEqual(0x2342, data.readUInt16BE(1));
  assert.strictEqual(0x423f, data.readUInt16BE(2));
  assert.strictEqual(0x2300, data.readUInt16LE(0));
  assert.strictEqual(0x4223, data.readUInt16LE(1));
  assert.strictEqual(0x3f42, data.readUInt16LE(2));

  data[0] = 0xfe;
  data[1] = 0xfe;
  assert.strictEqual(0xfefe, data.readUInt16BE(0));
  assert.strictEqual(0xfefe, data.readUInt16LE(0));
}


/*
 * Test 32 bit unsigned integers. We need to verify the same set as 8 bit, only
 * now some of the issues actually matter:
 *  - We are correctly resolving big endian
 *  - Correctly using the offsets
 *  - Correctly interpreting values that are beyond the signed range as unsigned
 */
function test32(clazz) {
  const data = new clazz(8);

  data[0] = 0x32;
  data[1] = 0x65;
  data[2] = 0x42;
  data[3] = 0x56;
  data[4] = 0x23;
  data[5] = 0xff;
  assert.strictEqual(0x32654256, data.readUInt32BE(0));
  assert.strictEqual(0x65425623, data.readUInt32BE(1));
  assert.strictEqual(0x425623ff, data.readUInt32BE(2));
  assert.strictEqual(0x56426532, data.readUInt32LE(0));
  assert.strictEqual(0x23564265, data.readUInt32LE(1));
  assert.strictEqual(0xff235642, data.readUInt32LE(2));
}


test8(Buffer);
test16(Buffer);
test32(Buffer);