# 1.1.0 listening-history FlatBuffers

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> Version: 1.1.0. Release requirements; implementation and delivery are recorded below.
> [Verification status](/Riff/1-1-0/status).

Wire owner: [format registry](/Riff/1-1-0/formats). HistoryEntry is a fixed 32-byte struct.
FileHeader is 32 bytes with 64-bit writer_id.

flags_data uses the most significant eight bits as flags and the low 56 bits as data. Within that
flag byte, bit 0 is Media.ID low-word presence; bits 1-2 are profile slot 1..3; bits 3-7 are
reserved zero. data is zero in version 1. An absent low word is encoded numerically as zero but
remains distinct from a present low word equal to zero. Profile flags match the header.

entries is oldest-to-newest. Equal generations retain accepted START order. The
[history owner](/Riff/1-1-0/history) defines generation and retention; the final binary may have
zero trailing padding to a 4096-byte boundary. Padding is not included in the vector length.

## listening_history.fbs

```fbs
include "state_common.fbs";

namespace link.roadio.riff.state.fbs;

struct HistoryEntry {
  generation:ulong;
  media_hi:long;
  media_lo:long;
  flags_data:ulong;
}

table ListeningHistory {
  header:FileHeader (required);
  entries:[HistoryEntry] (required);
}

root_type ListeningHistory;
file_identifier "PHST";
file_extension "fb";
```