+void journal_file_reset_location(JournalFile *f) {
+ f->location_type = LOCATION_HEAD;
+ f->current_offset = 0;
+ f->current_seqnum = 0;
+ f->current_realtime = 0;
+ f->current_monotonic = 0;
+ zero(f->current_boot_id);
+ f->current_xor_hash = 0;
+}
+
+void journal_file_save_location(JournalFile *f, direction_t direction, Object *o, uint64_t offset) {
+ f->last_direction = direction;
+ f->location_type = LOCATION_SEEK;
+ f->current_offset = offset;
+ f->current_seqnum = le64toh(o->entry.seqnum);
+ f->current_realtime = le64toh(o->entry.realtime);
+ f->current_monotonic = le64toh(o->entry.monotonic);
+ f->current_boot_id = o->entry.boot_id;
+ f->current_xor_hash = le64toh(o->entry.xor_hash);
+}
+
+int journal_file_compare_locations(JournalFile *af, JournalFile *bf) {
+ assert(af);
+ assert(bf);
+ assert(af->location_type == LOCATION_SEEK);
+ assert(bf->location_type == LOCATION_SEEK);
+
+ /* If contents and timestamps match, these entries are
+ * identical, even if the seqnum does not match */
+ if (sd_id128_equal(af->current_boot_id, bf->current_boot_id) &&
+ af->current_monotonic == bf->current_monotonic &&
+ af->current_realtime == bf->current_realtime &&
+ af->current_xor_hash == bf->current_xor_hash)
+ return 0;
+
+ if (sd_id128_equal(af->header->seqnum_id, bf->header->seqnum_id)) {
+
+ /* If this is from the same seqnum source, compare
+ * seqnums */
+ if (af->current_seqnum < bf->current_seqnum)
+ return -1;
+ if (af->current_seqnum > bf->current_seqnum)
+ return 1;
+
+ /* Wow! This is weird, different data but the same
+ * seqnums? Something is borked, but let's make the
+ * best of it and compare by time. */
+ }
+
+ if (sd_id128_equal(af->current_boot_id, bf->current_boot_id)) {
+
+ /* If the boot id matches, compare monotonic time */
+ if (af->current_monotonic < bf->current_monotonic)
+ return -1;
+ if (af->current_monotonic > bf->current_monotonic)
+ return 1;
+ }
+
+ /* Otherwise, compare UTC time */
+ if (af->current_realtime < bf->current_realtime)
+ return -1;
+ if (af->current_realtime > bf->current_realtime)
+ return 1;
+
+ /* Finally, compare by contents */
+ if (af->current_xor_hash < bf->current_xor_hash)
+ return -1;
+ if (af->current_xor_hash > bf->current_xor_hash)
+ return 1;
+
+ return 0;
+}
+