Component bdljsn_location [Package bdljsn]

Provide a value-semantic type for location in a JSON document. More...

Namespaces
namespace	bdljsn

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Detailed Description

Outline

• Purpose
• Classes
• Description
  • Attributes
  • Usage
    • Example 1: Basic Syntax

Purpose:

Provide a value-semantic type for location in a JSON document.

Classes:

bdljsn::Location

position in a JSON document

See also:

Component bdljsn_jsonutil, Component bdljsn_json

Description:

This component provides a single, unconstrained (value-semantic) attribute class, bdljsn::Location, that is used to describe a location in a (JSON) document. Location is expressed by the offset (attrbute) in bytes from the start of the document. See jsonutil for utilities that may provide bdljsn::Location values when reporting error states.

Attributes:

  Name                Type           Default
  ------------------  -------------  -------
  offset              bsl::uint64_t  0

• offset: the offset into the JSON document

Usage:

This section illustrates intended use of this component.

Example 1: Basic Syntax:

This example exercises each of the methods of the bdljsn::Location class.

First, create a bdljsn::Location object (having the default value):

  bdljsn::Location locationA;
  assert(0 == locationA.offset());

Then, set locationA to some other offset:

  locationA.setOffset(1);
  assert(1 == locationA.offset());

Next, use the value constructor to create a second location having the same offset as the first:

      bdljsn::Location locationB(1);
      assert(1         == locationB.offset());
      assert(locationA == locationB);

Then, set the second location to the maximum offset:

  const bsl::uint64_t maxOffset = bsl::numeric_limits<bsl::uint64_t>::max();

  locationB.setOffset(maxOffset);
  assert(maxOffset == locationB.offset());

Next, create another Location` that is a copy of the one at 'maxOffset:

  bdljsn::Location locationC(locationB);
  assert(locationB == locationC);

Then, set the first location back to the default state:

  locationA.reset();
  assert(0                  == locationA.offset());
  assert(bdljsn::Location() == locationA);

Next, print the value of each:

  bsl::cout << locationA << "\n"
            << locationB << bsl::endl;

  bsl::cout << "\n";

  locationC.print(bsl::cout, 2, 3);

and observe:

   0
   18446744073709551615

        [
           offset = 18446744073709551615
        ]

Finally, set each location equal to the first:

  locationC = locationB = locationA;
  assert(0 == locationA.offset());
  assert(0 == locationB.offset());
  assert(0 == locationC.offset());