mana: improve offset_ptr_t and related code

.clang-format

@@ -118,7 +118,7 @@ IncludeIsMainSourceRegex: ''
 IndentAccessModifiers: false
 IndentCaseBlocks: false
 IndentCaseLabels: false
-IndentExternBlock: AfterExternBlock
+IndentExternBlock: NoIndent
 IndentGotoLabels: true
 IndentPPDirectives: None
 IndentRequiresClause: true

src/internal/mana_arena.h

@@ -13,6 +13,11 @@
 namespace mesytec::mnode::mana
 {
 
+template <typename T> inline bool is_aligned(const T *ptr, size_t alignment = alignof(T))
+{
+    return (((uintptr_t)ptr) % alignment) == 0;
+}
+
 class Arena
 {
   public:
@@ -26,16 +31,11 @@ class Arena
     Arena(Arena &&other) = default;
     Arena &operator=(Arena &&other) = default;
 
-    // pushes at least the required amount of memory onto the arena.
-    // 'required' is rounded up to the nearest multiple of 'default_align_to' to make
-    // subsequent allocations aligned.
+    // Pushes at least the required amount of memory onto the arena. The memory is aligned to
+    // 'default_align_to' and zeroed
     u8 *push_size(size_t required)
     {
-        size_t padded = round_up(required, default_align_to);
-        size_t pad_waste = padded - required;
-        required = padded;
-
-        if (!segment_ || segment_->free() < required)
+        if (!segment_)
         {
             if (segment_count() < max_segments())
             {
@@ -52,12 +52,20 @@ class Arena
 
         assert(segment_ && segment_->free() >= required);
 
-        auto result = segment_->cur();
-        std::memset(result, 0, required);
-        segment_->used += required;
-        ++allocations_;
+        void *ptr = segment_->cur();
+        size_t space = segment_->free();
+        if (!std::align(default_align_to, required, ptr, space))
+            throw std::bad_alloc();
+
+        assert(is_aligned(ptr, default_align_to));
+
+        size_t pad_waste = segment_->free() - space;
+        segment_->used += required + pad_waste;
         pad_waste_ += pad_waste;
-        return result;
+        ++allocations_;
+
+        std::memset(ptr, 0, required);
+        return reinterpret_cast<u8 *>(ptr);
     }
 
     template <typename T> T *push_t(size_t count = 1)

src/internal/mana_c_api.h

@@ -9,42 +9,55 @@ extern "C"
 {
 #endif
 
-    typedef enum
-    {
+typedef enum
+{
     mana_custom,
     mana_uint8,
     mana_sint8,
     mana_uint16,
+    mana_sint16,
     mana_uint32,
+    mana_sint32,
     mana_uint64,
+    mana_sint64,
     mana_float,
     mana_double,
-    } mana_data_type_t;
+} mana_data_type_t;
 
-    typedef struct
-    {
+// Offset based pointer. Allows to memcpy() structures with these pointers
+// inside as long as the range covered by the pointers is also copied.
+//
+// Raw pointer value is '&ptr + offset'. nullptr is defined as offset=1.
+// => Cannot point to the first byte of the struct itself but that's fine.
+// Do not create temporaries of these. The offset will then be relative to the
+// temporary on the stack! Do not copy these unless you copy the full memory
+// range so that the offset_ptr_t in the new location stays valid.
+typedef struct
+{
     mana_data_type_t data_type;
     ptrdiff_t offset;
-    } mana_offset_ptr_t;
+} mana_offset_ptr_t;
 
-    typedef struct
-    {
+// Typed offset pointer based array. Stores the array size in bytes instead of
+// elements to allow storing any type using mana_custom.
+typedef struct
+{
     mana_offset_ptr_t ptr;
     size_t size_bytes;
-    } mana_offset_array_t;
+} mana_offset_array_t;
 
-    typedef enum
-    {
+typedef enum
+{
     mana_status_ok,
     mana_status_invalid_argument,
     mana_status_internal_error,
-    } mana_status_code_t;
+} mana_status_code_t;
 
-    typedef struct
-    {
+typedef struct
+{
     mana_status_code_t code;
     char message[256];
-    } mana_status_t;
+} mana_status_t;
 
 #define MANA_DEFINE_PLUGIN_INIT(name) void *name(int plugin_argc, const char **plugin_argv)
 
@@ -63,22 +76,22 @@ extern "C"
 #define MANA_DEFINE_PLUGIN_SYSTEM_EVENT(name)                                                      \
     void name(void *context, const uint32_t *data, size_t size)
 
-    typedef MANA_DEFINE_PLUGIN_INIT(mana_init_t);
-    typedef MANA_DEFINE_PLUGIN_SHUTDOWN(mana_shutdown_t);
-    typedef MANA_DEFINE_PLUGIN_BEGIN_RUN(mana_begin_run_t);
-    typedef MANA_DEFINE_PLUGIN_END_RUN(mana_end_run_t);
-    typedef MANA_DEFINE_PLUGIN_EVENT_DATA(mana_process_event_t);
-    typedef MANA_DEFINE_PLUGIN_SYSTEM_EVENT(mana_process_system_event_t);
+typedef MANA_DEFINE_PLUGIN_INIT(mana_init_t);
+typedef MANA_DEFINE_PLUGIN_SHUTDOWN(mana_shutdown_t);
+typedef MANA_DEFINE_PLUGIN_BEGIN_RUN(mana_begin_run_t);
+typedef MANA_DEFINE_PLUGIN_END_RUN(mana_end_run_t);
+typedef MANA_DEFINE_PLUGIN_EVENT_DATA(mana_process_event_t);
+typedef MANA_DEFINE_PLUGIN_SYSTEM_EVENT(mana_process_system_event_t);
 
-    typedef struct
-    {
+typedef struct
+{
     mana_init_t *init;
     mana_shutdown_t *shutdown;
     mana_begin_run_t *begin_run;
     mana_end_run_t *end_run;
     mana_process_event_t *process_event;
     mana_process_system_event_t *process_system_event;
-    } mana_sink_plugin_t;
+} mana_sink_plugin_t;
 
 // use this to define the entry point into the plugin
 // from c++: extern "C" MANA_C_SINK_PLUGIN() { ... return plugin; }

src/internal/mana_lib.hpp

@@ -16,8 +16,11 @@
 namespace mesytec::mnode::mana
 {
 
+inline bool is_null(const mana_offset_ptr_t &ptr) { return ptr.offset == 1; }
+
 namespace detail
 {
+
 inline void set(mana_offset_ptr_t &ptr, void *p)
 {
     assert(p != reinterpret_cast<u8 *>(&ptr) + 1);
@@ -33,31 +36,6 @@ inline void set(mana_offset_ptr_t &ptr, void *p)
         ptr.offset = 1;
     }
 }
-} // namespace detail
-
-inline bool is_null(const mana_offset_ptr_t &ptr) { return ptr.offset == 1; }
-
-inline void *get(mana_offset_ptr_t &ptr)
-{
-    return is_null(ptr) ? nullptr : reinterpret_cast<u8 *>(&ptr) + ptr.offset;
-}
-
-template <typename T> T *get(mana_offset_ptr_t &ptr); // to catch unsupported types
-
-template <typename T> T *get_(mana_offset_ptr_t &ptr, mana_data_type_t expected)
-{
-    if (ptr.data_type != expected)
-        return nullptr;
-
-    return reinterpret_cast<T *>(get(ptr));
-}
-
-template <> u32 *get(mana_offset_ptr_t &ptr) { return get_<u32>(ptr, mana_uint32); }
-template <> u64 *get(mana_offset_ptr_t &ptr) { return get_<u64>(ptr, mana_uint64); }
-template <> s8 *get(mana_offset_ptr_t &ptr) { return get_<s8>(ptr, mana_sint8); }
-template <> char *get(mana_offset_ptr_t &ptr) { return get_<char>(ptr, mana_sint8); }
-template <> float *get(mana_offset_ptr_t &ptr) { return get_<float>(ptr, mana_float); }
-template <> double *get(mana_offset_ptr_t &ptr) { return get_<double>(ptr, mana_double); }
 
 inline void set(mana_offset_ptr_t &ptr, mana_data_type_t data_type, void *p)
 {
@@ -65,13 +43,47 @@ inline void set(mana_offset_ptr_t &ptr, mana_data_type_t data_type, void *p)
     detail::set(ptr, p);
 }
 
-inline void set(mana_offset_ptr_t &ptr, std::nullptr_t) { set(ptr, mana_uint32, nullptr); }
-inline void set(mana_offset_ptr_t &ptr, u32 *p) { set(ptr, mana_uint32, p); }
-inline void set(mana_offset_ptr_t &ptr, u64 *p) { set(ptr, mana_uint64, p); }
-inline void set(mana_offset_ptr_t &ptr, s8 *p) { set(ptr, mana_sint8, p); }
-inline void set(mana_offset_ptr_t &ptr, char *p) { set(ptr, mana_sint8, p); }
-inline void set(mana_offset_ptr_t &ptr, float *p) { set(ptr, mana_float, p); }
-inline void set(mana_offset_ptr_t &ptr, double *p) { set(ptr, mana_double, p); }
+inline void *get(mana_offset_ptr_t &ptr)
+{
+    return is_null(ptr) ? nullptr : reinterpret_cast<u8 *>(&ptr) + ptr.offset;
+}
+
+template <typename T> T *get(mana_offset_ptr_t &ptr, mana_data_type_t expected)
+{
+    if (ptr.data_type != expected)
+        return nullptr;
+
+    return reinterpret_cast<T *>(get(ptr));
+}
+
+} // namespace detail
+
+template <typename T> T *get(mana_offset_ptr_t &ptr); // to catch unsupported types
+
+template <> u32 *get(mana_offset_ptr_t &ptr) { return detail::get<u32>(ptr, mana_uint32); }
+template <> u64 *get(mana_offset_ptr_t &ptr) { return detail::get<u64>(ptr, mana_uint64); }
+template <> s8 *get(mana_offset_ptr_t &ptr) { return detail::get<s8>(ptr, mana_sint8); }
+template <> char *get(mana_offset_ptr_t &ptr) { return detail::get<char>(ptr, mana_sint8); }
+template <> float *get(mana_offset_ptr_t &ptr) { return detail::get<float>(ptr, mana_float); }
+template <> double *get(mana_offset_ptr_t &ptr) { return detail::get<double>(ptr, mana_double); }
+
+// To make 'set(ptr, nullptr)' work.
+inline void set(mana_offset_ptr_t &ptr, std::nullptr_t)
+{
+    detail::set(ptr, ptr.data_type, nullptr);
+}
+
+inline void set(mana_offset_ptr_t &ptr, u8 *p) { detail::set(ptr, mana_uint8, p); }
+inline void set(mana_offset_ptr_t &ptr, s8 *p) { detail::set(ptr, mana_sint8, p); }
+inline void set(mana_offset_ptr_t &ptr, char *p) { detail::set(ptr, mana_sint8, p); }
+inline void set(mana_offset_ptr_t &ptr, u16 *p) { detail::set(ptr, mana_uint16, p); }
+inline void set(mana_offset_ptr_t &ptr, s16 *p) { detail::set(ptr, mana_sint16, p); }
+inline void set(mana_offset_ptr_t &ptr, u32 *p) { detail::set(ptr, mana_uint32, p); }
+inline void set(mana_offset_ptr_t &ptr, s32 *p) { detail::set(ptr, mana_sint32, p); }
+inline void set(mana_offset_ptr_t &ptr, u64 *p) { detail::set(ptr, mana_uint64, p); }
+inline void set(mana_offset_ptr_t &ptr, s64 *p) { detail::set(ptr, mana_sint64, p); }
+inline void set(mana_offset_ptr_t &ptr, float *p) { detail::set(ptr, mana_float, p); }
+inline void set(mana_offset_ptr_t &ptr, double *p) { detail::set(ptr, mana_double, p); }
 
 template <typename T>
 T *push_offset_array(mana::Arena &arena, mana_offset_array_t &dest, size_t size)
@@ -86,7 +98,7 @@ template <typename T>
 T *push_typed_offset_array(mana::Arena &arena, mana_offset_array_t &dest, size_t size)
 {
     T *ptr = arena.push_t<T>(size);
-    mana::set(dest.ptr, ptr);
+    set(dest.ptr, ptr);
     dest.size_bytes = size * sizeof(T);
     return ptr;
 }
@@ -98,7 +110,7 @@ template <typename T> size_t element_count(mana_offset_array_t &array)
 
 template <typename T> mvlc::util::span<T> get_span(mana_offset_array_t &array)
 {
-    auto ptr = reinterpret_cast<T *>(get(array.ptr));
+    auto ptr = get<T>(array.ptr);
     auto size = element_count<T>(array);
     return {ptr, size};
 }