+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright 2020 Philippe Proulx <pproulx@efficios.com>
+ */
+
+#include <babeltrace2/babeltrace.h>
+#include "common/macros.h"
+#include "common/assert.h"
+#include <glib.h>
+#include <stdint.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include "ctf-meta-visitors.h"
+
+static inline
+int set_alignments(struct ctf_field_class *fc)
+{
+ int ret = 0;
+ uint64_t i;
+
+ if (!fc) {
+ goto end;
+ }
+
+ switch (fc->type) {
+ case CTF_FIELD_CLASS_TYPE_STRUCT:
+ {
+ struct ctf_field_class_struct *struct_fc = (void *) fc;
+
+ for (i = 0; i < struct_fc->members->len; i++) {
+ struct ctf_named_field_class *named_fc =
+ ctf_field_class_struct_borrow_member_by_index(
+ struct_fc, i);
+
+ ret = set_alignments(named_fc->fc);
+ if (ret) {
+ goto end;
+ }
+
+ if (named_fc->fc->alignment > fc->alignment) {
+ fc->alignment = named_fc->fc->alignment;
+ }
+ }
+
+ break;
+ }
+ case CTF_FIELD_CLASS_TYPE_VARIANT:
+ {
+ struct ctf_field_class_variant *var_fc = (void *) fc;
+
+ for (i = 0; i < var_fc->options->len; i++) {
+ struct ctf_named_field_class *named_fc =
+ ctf_field_class_variant_borrow_option_by_index(
+ var_fc, i);
+
+ ret = set_alignments(named_fc->fc);
+ if (ret) {
+ goto end;
+ }
+ }
+
+ break;
+ }
+ case CTF_FIELD_CLASS_TYPE_ARRAY:
+ case CTF_FIELD_CLASS_TYPE_SEQUENCE:
+ {
+ struct ctf_field_class_array_base *array_fc = (void *) fc;
+
+ ret = set_alignments(array_fc->elem_fc);
+ if (ret) {
+ goto end;
+ }
+
+ /*
+ * Use the alignment of the array/sequence field class's
+ * element FC as its own alignment.
+ *
+ * This is especially important when the array/sequence
+ * field's effective length is zero: as per CTF 1.8, the
+ * stream data decoding process still needs to align the
+ * cursor using the element's alignment [1]:
+ *
+ * > Arrays are always aligned on their element
+ * > alignment requirement.
+ *
+ * For example:
+ *
+ * struct {
+ * integer { size = 8; } a;
+ * integer { size = 8; align = 16; } b[0];
+ * integer { size = 8; } c;
+ * };
+ *
+ * When using this to decode the bytes 1, 2, and 3, then
+ * the decoded values are:
+ *
+ * `a`: 1
+ * `b`: []
+ * `c`: 3
+ *
+ * [1]: https://diamon.org/ctf/#spec4.2.3
+ */
+ array_fc->base.alignment = array_fc->elem_fc->alignment;
+ break;
+ }
+ default:
+ break;
+ }
+
+end:
+ return ret;
+}
+
+BT_HIDDEN
+int ctf_trace_class_update_alignments(
+ struct ctf_trace_class *ctf_tc)
+{
+ int ret = 0;
+ uint64_t i;
+
+ if (!ctf_tc->is_translated) {
+ ret = set_alignments(ctf_tc->packet_header_fc);
+ if (ret) {
+ goto end;
+ }
+ }
+
+ for (i = 0; i < ctf_tc->stream_classes->len; i++) {
+ struct ctf_stream_class *sc = ctf_tc->stream_classes->pdata[i];
+ uint64_t j;
+
+ if (!sc->is_translated) {
+ ret = set_alignments(sc->packet_context_fc);
+ if (ret) {
+ goto end;
+ }
+
+ ret = set_alignments(sc->event_header_fc);
+ if (ret) {
+ goto end;
+ }
+
+ ret = set_alignments(sc->event_common_context_fc);
+ if (ret) {
+ goto end;
+ }
+ }
+
+ for (j = 0; j < sc->event_classes->len; j++) {
+ struct ctf_event_class *ec =
+ sc->event_classes->pdata[j];
+
+ if (ec->is_translated) {
+ continue;
+ }
+
+ ret = set_alignments(ec->spec_context_fc);
+ if (ret) {
+ goto end;
+ }
+
+ ret = set_alignments(ec->payload_fc);
+ if (ret) {
+ goto end;
+ }
+ }
+ }
+
+end:
+ return ret;
+}