--- /dev/null
+#ifndef _TRACEFILE_ARRAY_H
+#define _TRACEFILE_ARRAY_H
+
+/*
+ * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#include <limits.h>
+#include <inttypes.h>
+#include <pthread.h>
+#include <stdbool.h>
+
+struct tracefile {
+ /* Per-tracefile head/tail seq. */
+ uint64_t seq_head; /* Newest seqcount. Inclusive. */
+ uint64_t seq_tail; /* Oldest seqcount. Inclusive. */
+};
+
+enum tracefile_rotate_type {
+ TRACEFILE_ROTATE_READ,
+ TRACEFILE_ROTATE_WRITE,
+};
+
+/*
+ * Represents an array of trace files in a stream.
+ * head is the most recent file/trace packet.
+ * tail is the oldest file/trace packet.
+ *
+ * There are two heads: a "read" head and a "write" head. The "write" head is
+ * the position of the newest data file. The "read" head position is only moved
+ * forward when the index is received.
+ *
+ * The viewer uses the "read" head position as upper bound, which
+ * ensures it never attempts to open a non-existing index file.
+ */
+struct tracefile_array {
+ struct tracefile *tf;
+ size_t count;
+
+ /* Current head/tail files. */
+ uint64_t file_head_read;
+ uint64_t file_head_write;
+ uint64_t file_tail;
+
+ /* Overall head/tail seq for the entire array. Inclusive. */
+ uint64_t seq_head;
+ uint64_t seq_tail;
+};
+
+struct tracefile_array *tracefile_array_create(size_t count);
+void tracefile_array_destroy(struct tracefile_array *tfa);
+
+void tracefile_array_file_rotate(struct tracefile_array *tfa, enum tracefile_rotate_type type);
+void tracefile_array_commit_seq(struct tracefile_array *tfa,
+ uint64_t new_seq_head);
+void tracefile_array_reset(struct tracefile_array *tfa);
+
+uint64_t tracefile_array_get_read_file_index_head(struct tracefile_array *tfa);
+/* May return -1ULL in the case where we have not received any indexes yet. */
+uint64_t tracefile_array_get_seq_head(struct tracefile_array *tfa);
+
+uint64_t tracefile_array_get_file_index_tail(struct tracefile_array *tfa);
+/* May return -1ULL in the case where we have not received any indexes yet. */
+uint64_t tracefile_array_get_seq_tail(struct tracefile_array *tfa);
+
+bool tracefile_array_seq_in_file(struct tracefile_array *tfa,
+ uint64_t file_index, uint64_t seq);
+
+#endif /* _STREAM_H */