Detailed Description

XMPP (RFC 6120) stanza codec (PC_ENABLE_XMPP).

XMPP (Jabber) is an XML streaming protocol: after a <stream:stream> open, peers exchange three stanza kinds - <message>, <presence>, and <iq> (info/query). This is the stanza codec: builders that emit correctly XML-escaped stanzas into a caller buffer (so a device can publish sensor data or receive commands as an IoT XMPP client), plus minimal readers to pull the stanza element name and an attribute value out of a received stanza.

Pure text framing, zero heap, no stdlib, host-testable. TLS (starttls) + SASL auth ride the existing client TLS path; the IoT XEPs (0323 sensor-data, 0325 control) layer their payloads inside <iq>.

Definition in file xmpp.h.