Base escaping only escapes values required for base character data
according to part 2.4 of XML, and if additional flags are added
single and double quotes can additionally be escaped in order
to handle single and double quoted attributes.
Co-authored-by: Jan Ekström <jan.ekstrom@24i.com>
Signed-off-by: Jan Ekström <jan.ekstrom@24i.com>
The escape API will be useful to perform escaping programmatically, which
is required when crafting argument strings, and will be used for context
printing as well.
This is based on the ffescape tool code, with a few extensions and fixes.
