Minireflect fixed array (#6129)

* CMakeLists: also really generate optional_scalars as needed by test elsewhere

* [C++] Handle fixed-length array in minireflection

Fixes #6128

2 files changed, 20 insertions, 8 deletions

diff --git a/include/flatbuffers/flatbuffers.h b/include/flatbuffers/flatbuffers.h
index 28441248..799f6478 100644
--- a/include/flatbuffers/flatbuffers.h
+++ b/include/flatbuffers/flatbuffers.h
@@ -2747,7 +2747,7 @@ inline const char * const *ElementaryTypeNames() {
 // Basic type info cost just 16bits per field!
 struct TypeCode {
   uint16_t base_type : 4;  // ElementaryType
-  uint16_t is_vector : 1;
+  uint16_t is_repeating : 1;  // Either vector (in table) or array (in struct)
   int16_t sequence_ref : 11;  // Index into type_refs below, or -1 for none.
 };
 
@@ -2763,6 +2763,7 @@ struct TypeTable {
   size_t num_elems;  // of type_codes, values, names (but not type_refs).
   const TypeCode *type_codes;     // num_elems count
   const TypeFunction *type_refs;  // less than num_elems entries (see TypeCode).
+  const int16_t *array_sizes;     // less than num_elems entries (see TypeCode).
   const int64_t *values;  // Only set for non-consecutive enum/union or structs.
   const char *const *names;  // Only set if compiled with --reflect-names.
 };
diff --git a/include/flatbuffers/minireflect.h b/include/flatbuffers/minireflect.h
index c2babdcc..26fd86c9 100644
--- a/include/flatbuffers/minireflect.h
+++ b/include/flatbuffers/minireflect.h
@@ -234,10 +234,11 @@ inline void IterateObject(const uint8_t *obj, const TypeTable *type_table,
   visitor->StartSequence();
   const uint8_t *prev_val = nullptr;
   size_t set_idx = 0;
+  size_t array_idx = 0;
   for (size_t i = 0; i < type_table->num_elems; i++) {
     auto type_code = type_table->type_codes[i];
     auto type = static_cast<ElementaryType>(type_code.base_type);
-    auto is_vector = type_code.is_vector != 0;
+    auto is_repeating = type_code.is_repeating != 0;
     auto ref_idx = type_code.sequence_ref;
     const TypeTable *ref = nullptr;
     if (ref_idx >= 0) { ref = type_table->type_refs[ref_idx](); }
@@ -249,15 +250,25 @@ inline void IterateObject(const uint8_t *obj, const TypeTable *type_table,
     } else {
       val = obj + type_table->values[i];
     }
-    visitor->Field(i, set_idx, type, is_vector, ref, name, val);
+    visitor->Field(i, set_idx, type, is_repeating, ref, name, val);
     if (val) {
       set_idx++;
-      if (is_vector) {
-        val += ReadScalar<uoffset_t>(val);
-        auto vec = reinterpret_cast<const Vector<uint8_t> *>(val);
+      if (is_repeating) {
+        auto elem_ptr = val;
+        size_t size = 0;
+        if (type_table->st == ST_TABLE) {
+          // variable length vector
+          val += ReadScalar<uoffset_t>(val);
+          auto vec = reinterpret_cast<const Vector<uint8_t> *>(val);
+          elem_ptr = vec->Data();
+          size = vec->size();
+        } else {
+          // otherwise fixed size array
+          size = type_table->array_sizes[array_idx];
+          ++array_idx;
+        }
         visitor->StartVector();
-        auto elem_ptr = vec->Data();
-        for (size_t j = 0; j < vec->size(); j++) {
+        for (size_t j = 0; j < size; j++) {
           visitor->Element(j, type, ref, elem_ptr);
           IterateValue(type, elem_ptr, ref, prev_val, static_cast<soffset_t>(j),
                        visitor);