src/plugins/ctf/common: restructure subtree

[babeltrace.git] / src / plugins / ctf / common / src / metadata / tsdl / ctf-meta-update-alignments.cpp

diff --git a/src/plugins/ctf/common/src/metadata/tsdl/ctf-meta-update-alignments.cpp b/src/plugins/ctf/common/src/metadata/tsdl/ctf-meta-update-alignments.cpp
new file mode 100644 (file)
index 0000000..bea62bf
--- /dev/null
+++ b/src/plugins/ctf/common/src/metadata/tsdl/ctf-meta-update-alignments.cpp
@@ -0,0 +1,161 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright 2020 Philippe Proulx <pproulx@efficios.com>
+ */
+
+#include <stdint.h>
+
+#include "ctf-meta-visitors.hpp"
+
+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 = ctf_field_class_as_struct(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 = ctf_field_class_as_variant(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 = ctf_field_class_as_array_base(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;
+}
+
+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++) {
+        ctf_stream_class *sc = (ctf_stream_class *) 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 = (ctf_event_class *) 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;
+}