Added entity queries by tag, tests for queries and tests for tagging.

core/build-config/tests.txt

@@ -1,3 +1,5 @@
 tests/internal/basic-tag-registry-usage
 tests/internal/entity-lookup
-tests/interface/entity-creation
+tests/interface/entity-queries
+tests/interface/entity-creation
+tests/interface/entity-tagging-api

core/exports/maintree/maintree.h

@@ -14,6 +14,7 @@ typedef void           MtState;
 
 typedef void (*MtEffectorFn) (MtEntity *entity, void *userdata, usz_t invocation_id);
 typedef void (*MtTaskMainFn) (MtTask *task, void *userdata);
+typedef bool_t (*MtQueryMatcherFn) (MtEntity *entity, void *userdata);
 
 typedef struct
 {
@@ -48,6 +49,9 @@ void mt_remove_effector(MtState *state, const char *effector_name);
 /// @param tag_names A nullpointer-terminated list of tag-ids that must be present in an entity for that entity to be effected.
 void mt_add_tagged_tick_effector(MtState *state, char *effector_name, usz_t ticks_delta, MtEffectorFn function, char **tag_names);
 
+usz_t mt_query(MtState *state, const char **tags, MtEntity **entities, usz_t count);
+usz_t mt_match_query(MtState *state, const char **tags, MtEntity **entities, usz_t count, MtQueryMatcherFn matcher, void *userdata);
+
 void mt_tag_i64(MtEntity *entity, char *name, i64_t integer);
 void mt_tag_f64(MtEntity *entity, char *name, f64_t real);
 void mt_tag_str(MtEntity *entity, char *name, char *string);

core/inc-c/entity.h

@@ -89,6 +89,7 @@ void mt_tag_vec2(MtEntity *entity, char *name, rr_vec2f_s vector);
 void mt_tag_vec3(MtEntity *entity, char *name, rr_vec3f_s vector);
 void mt_tag_vec4(MtEntity *entity, char *name, rr_vec4f_s vector);
 
+bool_t mt_has_tag(MtEntity *entity, const char *name);
 void mt_untag(MtEntity *entity, char *name);
 
 i64_t mt_get_i64_tag(MtEntity *entity, char *name);

core/inc-c/state.h

@@ -9,6 +9,7 @@
 #include <librr/alloc/generic.h>
 
 typedef struct MtState          MtState;
+typedef bool_t (*MtQueryMatcherFn) (MtEntity *entity, void *userdata);
 
 struct MtState
 {
@@ -25,4 +26,7 @@ void mt_start(MtState *state);
 MtEntity * mt_summon(MtState *state);
 void mt_drop(MtEntity *entity);
 
+usz_t mt_query(MtState *state, const char **tags, MtEntity **entities, usz_t count);
+usz_t mt_match_query(MtState *state, const char **tags, MtEntity **entities, usz_t count, MtQueryMatcherFn matcher, void *userdata);
+
 #endif // MT_STATE_H

core/inc-c/tag_registry.h

@@ -30,6 +30,11 @@ struct MtTagEntry
 {
     u32_t                       identifier;
     char                       *label;
+
+    usz_t                       entities_capacity;
+    usz_t                       num_entities;
+    /// @brief An array ofhe identifiers of all entities which have a tag of this type.
+    u32_t                      *entity_identifiers;
 };
 
 struct MtTagCollection
@@ -46,5 +51,9 @@ void mt_delete_tag_registry(MtTagRegistry registry);
 
 u32_t mt_get_tag_id(MtTagRegistry *registry, const char *tag_label);
 const char * mt_get_tag_label(MtTagRegistry *registry, u32_t tag_identifier);
+MtTagEntry * mt_get_tag_entry(MtTagRegistry *registry, const char *tag_label);
+
+void mt_add_entity_to_tag_lookup_list(MtTagRegistry *registry, const char *tag_label, u32_t entity_identifier);
+void mt_remove_entity_from_tag_lookup_list(MtTagRegistry *registry, const char *tag_label, u32_t entity_identifier);
 
 #endif // MT_TAG_REGISTRY_H

core/src-c/entity_registry.c

@@ -89,6 +89,7 @@ void mt_delete_entity_data(MtEntity *entity)
 {
     if(entity->tags != NULL)
         free(entity->tags);
+    entity->tags = NULL;
 }
 
 

core/src-c/entity_tagging.c

@@ -20,6 +20,8 @@ i16_t mt_get_entity_tag_slot_index(MtEntity *entity, const char *name)
 
 MtTag * mt_get_entity_tag_slot(MtEntity *entity, char *name)
 {
+    MtState *state = entity->parent_state;
+
     i16_t tag_slot_index = mt_get_entity_tag_slot_index(entity, name);
     if(tag_slot_index >= 0)
         return &entity->tags[tag_slot_index];
@@ -34,51 +36,87 @@ MtTag * mt_get_entity_tag_slot(MtEntity *entity, char *name)
 
         entity->tags = realloc(entity->tags, sizeof(struct MtTag) * entity->tags_capacity);
     }
+    entity->tags[entity->num_tags].identifier = mt_get_tag_id(&state->tag_registry, name);
     return &entity->tags[entity->num_tags++];
 }
 
 void mt_tag_i64(MtEntity *entity, char *name, i64_t integer)
 {
+    MtState *state = entity->parent_state;
     MtTag *tag = mt_get_entity_tag_slot(entity, name);
+
+    mt_add_entity_to_tag_lookup_list(&state->tag_registry, name, entity->identifier);
     tag->data.integer = integer;
 }
 
 void mt_tag_f64(MtEntity *entity, char *name, f64_t real)
 {
+    MtState *state = entity->parent_state;
     MtTag *tag = mt_get_entity_tag_slot(entity, name);
+
+    mt_add_entity_to_tag_lookup_list(&state->tag_registry, name, entity->identifier);
     tag->data.real = real;
 }
 
 void mt_tag_str(MtEntity *entity, char *name, char *string)
 {
+    MtState *state = entity->parent_state;
     MtTag *tag = mt_get_entity_tag_slot(entity, name);
+
+    mt_add_entity_to_tag_lookup_list(&state->tag_registry, name, entity->identifier);
     tag->data.string = string;
 }
 
 void mt_tag_ptr(MtEntity *entity, char *name, void *pointer)
 {
+    MtState *state = entity->parent_state;
     MtTag *tag = mt_get_entity_tag_slot(entity, name);
+
+    mt_add_entity_to_tag_lookup_list(&state->tag_registry, name, entity->identifier);
     tag->data.pointer = pointer;
 }
 
 void mt_tag_vec2(MtEntity *entity, char *name, rr_vec2f_s vector)
 {
+    MtState *state = entity->parent_state;
     MtTag *tag = mt_get_entity_tag_slot(entity, name);
+
+    mt_add_entity_to_tag_lookup_list(&state->tag_registry, name, entity->identifier);
     tag->data.vec2f = vector;
 }
 
 void mt_tag_vec3(MtEntity *entity, char *name, rr_vec3f_s vector)
 {
+    MtState *state = entity->parent_state;
     MtTag *tag = mt_get_entity_tag_slot(entity, name);
+
+    mt_add_entity_to_tag_lookup_list(&state->tag_registry, name, entity->identifier);
     tag->data.vec3f = vector;
 }
 void mt_tag_vec4(MtEntity *entity, char *name, rr_vec4f_s vector)
 {
+    MtState *state = entity->parent_state;
     MtTag *tag = mt_get_entity_tag_slot(entity, name);
+
+    mt_add_entity_to_tag_lookup_list(&state->tag_registry, name, entity->identifier);
     tag->data.vec4f = vector;
 }
 
+bool_t mt_has_tag(MtEntity *entity, const char *name)
+{
+    MtState *state = entity->parent_state;
+    usz_t tag_id = mt_get_tag_id(&state->tag_registry, name);
 
+    usz_t tag_index = 0;
+    while(tag_index < entity->num_tags)
+    {
+        if(entity->tags[tag_index].identifier == tag_id)
+            return TRUE;
+
+        ++tag_index;
+    }
+    return FALSE;
+}
 
 void mt_untag(MtEntity *entity, char *name)
 {

core/src-c/queries.c

@@ -0,0 +1,107 @@
+#include <state.h>
+#include <entity.h>
+
+usz_t mt_find_tag_with_least_entries(MtState *state, const char **tags)
+{
+    u32_t least_entries_count = 0xffffffff;
+    usz_t least_entries_index = 0;
+
+    usz_t tag_index = 0;
+    while(tags[tag_index] != NULL)
+    {
+        MtTagEntry *tag_entry = mt_get_tag_entry(&state->tag_registry, tags[tag_index]);
+        if(tag_entry->num_entities > least_entries_count)
+        {
+            least_entries_count = tag_entry->num_entities;
+            least_entries_index = tag_index;
+        }
+        ++tag_index;
+    }
+    return least_entries_index;
+}
+
+usz_t mt_count_entities_with_matching_tags(MtState *state, const char **tags)
+{
+    usz_t num_matching_entities = 0;
+
+    const char *least_used_tag = tags[mt_find_tag_with_least_entries(state, tags)];
+    MtTagEntry *tag_entry = mt_get_tag_entry(&state->tag_registry, least_used_tag);
+    usz_t entity_index = 0;
+    while(entity_index < tag_entry->num_entities)
+    {
+        MtEntity *entity = mt_get_entity(state, tag_entry->entity_identifiers[entity_index]);
+        bool_t matching = TRUE;
+        usz_t wanted_tag_index = 0;
+        while(tags[wanted_tag_index] != NULL)
+        {
+            if(!mt_has_tag(entity, tags[wanted_tag_index]))
+            {
+                matching = FALSE;
+                break;
+            }
+            ++wanted_tag_index;
+        }
+        if(matching)
+            ++num_matching_entities;
+        
+        ++entity_index;
+    }
+    return num_matching_entities;
+}
+
+usz_t mt_query(MtState *state, const char **tags, MtEntity **entities, usz_t count)
+{
+    if(count == 0)
+        return mt_count_entities_with_matching_tags(state, tags);;
+    
+    usz_t num_written_entities = 0;
+    const char *least_used_tag = tags[mt_find_tag_with_least_entries(state, tags)];
+    MtTagEntry *tag_entry = mt_get_tag_entry(&state->tag_registry, least_used_tag);
+    usz_t entity_index = 0;
+    while((entity_index < tag_entry->num_entities) && (num_written_entities < count))
+    {
+        MtEntity *entity = mt_get_entity(state, tag_entry->entity_identifiers[entity_index]);
+        bool_t matching = TRUE;
+        usz_t wanted_tag_index = 0;
+        while(tags[wanted_tag_index] != NULL)
+        {
+            if(!mt_has_tag(entity, tags[wanted_tag_index]))
+            {
+                matching = FALSE;
+                break;
+            }
+            ++wanted_tag_index;
+        }
+        if(matching)
+        {
+            entities[num_written_entities] = entity;
+            ++num_written_entities;
+        }
+        ++entity_index;
+    }
+    return num_written_entities;
+}
+
+usz_t mt_match_query(MtState *state, const char **tags, MtEntity **entities, usz_t count, MtQueryMatcherFn matcher, void *userdata)
+{
+    usz_t num_matching_entities = mt_query(state, tags, entities, 0);
+    if(count == 0)
+        return num_matching_entities;
+    
+    // TODO: If 'num_matching_entities" is too big, this must be allocated on the heap!
+    MtEntity *generally_matching_entities[num_matching_entities];
+    mt_query(state, tags, &generally_matching_entities[0], num_matching_entities);
+    
+    usz_t written_entities = 0;
+    usz_t entity_index = 0;
+    while((entity_index < num_matching_entities) && (written_entities < count))
+    {
+        if(matcher(generally_matching_entities[entity_index], userdata))
+        {
+            entities[written_entities] = generally_matching_entities[entity_index];
+            ++written_entities;
+        }
+        ++entity_index;
+    }
+    return written_entities;
+}

core/src-c/tag_registry.c

@@ -3,6 +3,8 @@
 #include <librr/memory.h>
 #include <stdlib.h>
 
+#define MT_INITIAL_ENTITIES_CAPACITY_PER_TAG 32
+
 MtTagRegistry mt_create_tag_registry(void *parent_state)
 {
     MtTagRegistry registry;
@@ -93,7 +95,9 @@ MtTagEntry * mt_create_tag_hash_entry(MtTagRegistry *registry, const char *tag_l
     // TODO: There MUST be an arena allocator for this!
     entry->label = malloc(len_tag_label + 1);
     rr_memcopy(entry->label, tag_label, len_tag_label+1);
-
+    entry->entities_capacity = MT_INITIAL_ENTITIES_CAPACITY_PER_TAG;
+    entry->entity_identifiers = calloc(sizeof(u32_t), entry->entities_capacity);
+    entry->num_entities = 0;
     entry->identifier = registry->next_identifier;
     ++registry->next_identifier;
 
@@ -120,7 +124,7 @@ MtTagEntry * mt_create_tag_hash_entry(MtTagRegistry *registry, const char *tag_l
     return entry;
 }
 
-u32_t mt_get_tag_id(MtTagRegistry *registry, const char *tag_label)
+MtTagEntry * mt_get_tag_entry(MtTagRegistry *registry, const char *tag_label)
 {
     u32_t collection_index = mt_tag_label_to_hash(tag_label, registry->num_collections);
     MtTagCollection collection = registry->collections[collection_index];
@@ -129,12 +133,16 @@ u32_t mt_get_tag_id(MtTagRegistry *registry, const char *tag_label)
     {
         MtTagEntry *entry = &registry->entries[collection.tag_indices[entry_index]];
         if(rr_strings_equal(entry->label, tag_label))
-            return entry->identifier;
+            return entry;
 
         ++entry_index;
     }
-    MtTagEntry *entry = mt_create_tag_hash_entry(registry, tag_label);
+    return mt_create_tag_hash_entry(registry, tag_label);
-    return entry->identifier;
+}
+
+u32_t mt_get_tag_id(MtTagRegistry *registry, const char *tag_label)
+{
+    return mt_get_tag_entry(registry, tag_label)->identifier;
 }
 
 const char * mt_get_tag_label(MtTagRegistry *registry, u32_t tag_identifier)
@@ -150,3 +158,47 @@ const char * mt_get_tag_label(MtTagRegistry *registry, u32_t tag_identifier)
     }
     return NULL;
 }
+
+u32_t mt_get_or_create_entity_id_slot_in_tag_entry(MtTagEntry *entry, u32_t entity_identifier)
+{
+    // Option 1: Find the entity identifier (if it was already registered)
+
+    usz_t index = 0;
+    while(index < entry->num_entities)
+    {
+        if(entry->entity_identifiers[index] == entity_identifier)
+            return index;
+
+        ++index;
+    }
+
+    // Option 2: Get a slot for the entity identifier and write the ID.
+
+    // Resize the entity_identifiers array if needed
+
+    if(entry->num_entities >= entry->entities_capacity)
+    {
+        entry->entities_capacity *= 2;
+        if(entry->entities_capacity == 0)
+            entry->entities_capacity = MT_INITIAL_ENTITIES_CAPACITY_PER_TAG;
+        entry->entity_identifiers = realloc(entry->entity_identifiers, sizeof(u32_t) * entry->entities_capacity);
+    }
+    usz_t entity_identifier_index = entry->num_entities;
+    entry->entity_identifiers[entity_identifier_index] = entity_identifier;
+    ++entry->num_entities;
+    return entity_identifier_index;
+}
+
+void mt_add_entity_to_tag_lookup_list(MtTagRegistry *registry, const char *tag_label, u32_t entity_identifier)
+{
+    MtTagEntry *entry = mt_get_tag_entry(registry, tag_label);
+    mt_get_or_create_entity_id_slot_in_tag_entry(entry, entity_identifier);
+}
+
+void mt_remove_entity_from_tag_lookup_list(MtTagRegistry *registry, const char *tag_label, u32_t entity_identifier)
+{
+    MtTagEntry *entry = mt_get_tag_entry(registry, tag_label);
+    u32_t entity_index = mt_get_or_create_entity_id_slot_in_tag_entry(entry, entity_identifier);
+    entry->entity_identifiers[entity_index] = entry->entity_identifiers[entry->num_entities-1];
+    --entry->num_entities;
+}

core/tests/interface/entity-queries/main.c

@@ -0,0 +1,49 @@
+#include <state.h>
+#include <entity.h>
+
+#include <stdio.h>
+
+int main()
+{
+    MtState *state = mt_initialize("Interface Test");
+    MtEntity *entity_1 = mt_summon(state);
+    mt_tag_i64(entity_1, "some_tag", 3);
+    mt_tag_i64(entity_1, "another_tag", 42);
+    mt_tag_i64(entity_1, "listed_tag", 1337);
+
+    MtEntity *entity_2 = mt_summon(state);
+    mt_tag_i64(entity_2, "some_tag", 3);
+    mt_tag_i64(entity_2, "another_tag", 42);
+
+    MtEntity *entity_3 = mt_summon(state);
+    mt_tag_i64(entity_3, "some_tag", 3);
+    mt_tag_i64(entity_3, "another_tag", 42);
+    mt_tag_i64(entity_3, "listed_tag", 236512);
+
+    const char *tag_list[4] =
+    {
+        "some_tag",
+        "another_tag",
+        "listed_tag",
+        NULL
+    };
+    usz_t num_matching_entities = mt_query(state, tag_list, NULL, 0);
+    printf("Number of matching entities: %ld\n", num_matching_entities);
+
+    MtEntity *entities[8];
+    mt_query(state, tag_list, entities, 8);
+
+    printf("Entity 1: %p\nEntity 2: %p\nEntity 3: %p\n", (void *) entity_1, (void *) entity_2, (void *) entity_3);
+    usz_t entity_index = 0;
+    while(entity_index < num_matching_entities)
+    {
+        printf("Entity-Pointer: %p\n", (void *) entities[entity_index]);
+        ++entity_index;
+    }
+
+    mt_drop(entity_1);
+    mt_drop(entity_2);
+    mt_drop(entity_3);
+    mt_cleanup(state);
+    return 0;
+}

core/tests/interface/entity-tagging-api/main.c

@@ -0,0 +1,26 @@
+#include <maintree/maintree.h>
+#include <stdio.h>
+
+#define TEST_INTEGER 1337
+
+int main()
+{
+    MtState *state = mt_initialize("Interface Test");
+    MtEntity* entity = mt_summon(state);
+    mt_tag_i64(entity, "test-tag", TEST_INTEGER);
+    i64_t returned_integer = mt_get_i64_tag(entity, "test-tag");
+    if(returned_integer != TEST_INTEGER)
+    {
+        puts("The integer returned from the get_i64_tag-function doesn't match the tag which was put in!");
+        printf("Input:  %d\nOutput: %ld\n", TEST_INTEGER, returned_integer);
+        mt_drop(entity);
+        mt_cleanup(state);
+        return -1;
+    }
+
+    mt_drop(entity);
+    mt_cleanup(state);
+    puts("The program reached the end; this test is considered as passed. SUCCESS!");
+    puts("Note: A memory leak check utility should be used to verify the success.");
+    return 0;
+}

core/tests/internal/entity-lookup/main.c

@@ -5,7 +5,7 @@
 
 int main()
 {
-    MtState *state = mt_initialize("Interface Test");;
+    MtState *state = mt_initialize("Internal Test");
     MtEntity *entity = mt_summon(state);
     MtEntity *looked_up_entity = mt_get_entity(state, entity->identifier);