This commit changes the `String<kSize>` class to inherit from
`StringWriter` class. It helps simplify their use allowing
`StringWriter` methods to be directly called on an `String` instance
while ensuring the implementation is still shared among all template
variants of `String<kSize>` class. This change also ensures that
`String<kSize>` is always initialized and set to an empty string from
its constructor.
This commit fixes an issue with some of the log related methods where
`String` object may be used without being initialized (this was added
from commit b39f5b6dd and PR #6564).
This commit ensures that `String` variable definitions are always
immediately followed by a `StringWriter()` definition which then
initializes the string buffer (sets it as empty).
This commit also updates `test_string` unit test.
This commit moves methods of String out of the header file to save code
size.
Since most use cases of String writers ignores errors, this commit
changes the return of writers to the Writer object itself for chained
writes.
This commit adds `Dns::Name` type which provides a set of helper
methods to encode/decode DNS names. `AppendName()` method encodes and
appends a full name (e.g., "test.example.com") to a message. Other
helper methods enable appending labels (or groups of labels) and/or
constructing a compressed name (using pointer labels). `ParseName()`
method parses and skips over a full name in a message. `ReadLabel()`
method reads labels one by one and works independently of whether the
encoded name is compressed or not. `ReadName()` method read an entire
name from message. The new methods are used in `Dns::Client`.
This commit also add a unit test `test-dns` covering the behavior of
the newly added helper methods.
Finally, this commit adds few helper methods in `ResourceRecords` to
get the size and check the type of a DNS record.
This commit adds a new template class `ot::String<size>` which
implements a fixed-length character string. This class is then used as
return value of `ToString()` methods from different classes. This
simplifies the `ToString()` implementation and its use. This commit
also adds a unit test for `String`.
Abtin Keshavarzian