From 11048808cbe3dc77bb2bee6d2643a33a45574509 Mon Sep 17 00:00:00 2001
From: Andrew Guschin <saintruler@gmail.com>
Date: Mon, 13 Sep 2021 16:10:57 +0400
Subject: Added bitset

---
 src/bitset.c  | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/bitset.h  | 44 +++++++++++++++++++++++++++++++
 src/main.c    | 15 +++++++++++
 src/storage.h |  4 +++
 4 files changed, 148 insertions(+)
 create mode 100644 src/bitset.c
 create mode 100644 src/bitset.h

(limited to 'src')

diff --git a/src/bitset.c b/src/bitset.c
new file mode 100644
index 0000000..0d2f66a
--- /dev/null
+++ b/src/bitset.c
@@ -0,0 +1,85 @@
+#include "bitset.h"
+
+void
+bitarena_init(bitarena_t *arena, int size)
+{
+	arena->size = size;
+	size_t memSize = sizeof(char) * BITSET_BYTES * size;
+	arena->arena = malloc(memSize);
+	memset(arena->arena, 0, memSize);
+}
+
+bitset_t
+bitset_create()
+{
+	bitset_t tmp = (bitset_t) malloc(sizeof(char) * BITSET_BYTES);
+	memset(tmp, 0, sizeof(char) * BITSET_BYTES);
+	return tmp;
+}
+
+bitset_t
+bitarena_at(bitarena_t *arena, int idx)
+{
+	return (arena->arena) + (idx * BITSET_BYTES);
+}
+
+bitset_t
+bitset_and(bitset_t b1, bitset_t b2)
+{
+	bitset_t bitAnd = bitset_create();
+
+	for (int i = 0; i < BITSET_BYTES; ++i)
+	{
+		bitAnd[i] = b1[i] & b2[i];
+	}
+
+	return bitAnd;
+}
+
+int
+bitset_isZero(bitset_t bitset)
+{
+	for (int i = 0; i < BITSET_BYTES; ++i)
+	{
+		if (bitset[i] != 0)
+			return 0;
+	}
+	return 1;
+}
+
+void
+bitset_set(bitset_t bitset, int position)
+{
+	int byte = position / (sizeof(char) * 8);
+	int shift = position % (sizeof(char) * 8);
+	bitset[byte] = bitset[byte] | (1 << shift);
+}
+
+void
+bitset_unset(bitset_t bitset, int position)
+{
+	int byte = position / (sizeof(char) * 8);
+	int shift = position % (sizeof(char) * 8);
+	bitset[byte] = bitset[byte] &  ~(1 << shift);
+}
+
+int
+bitset_equals(bitset_t b1, bitset_t b2)
+{
+	for (int i = 0; i < BITSET_BYTES; ++i)
+	{
+		if (b1[i] != b2[i])
+			return 0;
+	}
+	return 1;
+}
+
+void
+bitset_print(bitset_t bitset)
+{
+	for (int i = 3; i >= 0; --i)
+	{
+		printf("%i ", bitset[i]);
+	}
+	printf("\n");
+}
diff --git a/src/bitset.h b/src/bitset.h
new file mode 100644
index 0000000..0c5092d
--- /dev/null
+++ b/src/bitset.h
@@ -0,0 +1,44 @@
+#ifndef bitset_h_INCLUDED
+#define bitset_h_INCLUDED
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifndef BITSET_BYTES
+#define BITSET_BYTES 4
+#endif
+
+typedef struct
+{
+	int size;
+	char *arena;
+} bitarena_t;
+
+typedef char* bitset_t;
+
+void
+bitarena_init(bitarena_t *arena, int size);
+
+bitset_t
+bitarena_at(bitarena_t *arena, int idx);
+
+bitset_t
+bitset_and(bitset_t b1, bitset_t b2);
+
+int
+bitset_isZero(bitset_t bitset);
+
+void
+bitset_set(bitset_t bitset, int position);
+
+void
+bitset_unset(bitset_t bitset, int position);
+
+int
+bitset_equals(bitset_t b1, bitset_t b2);
+
+void
+bitset_print(bitset_t bitset);
+
+#endif // bitset_h_INCLUDED
diff --git a/src/main.c b/src/main.c
index ad50fd5..e09cd18 100644
--- a/src/main.c
+++ b/src/main.c
@@ -3,6 +3,7 @@
 #include <string.h>
 
 #include "storage.h"
+#include "bitset.h"
 
 typedef struct
 {
@@ -29,6 +30,7 @@ initStorage(storage_t *storage)
 	storage->componentsStored = 0;
 	storage->objectsStored = 0;
 	storage->objects = (component_pair_t *) malloc(MAX_COMPONENTS * sizeof(component_pair_t));
+	bitarena_init(&storage->objectSignatures, MAX_OBJECTS);
 
 	REGISTER_COMPONENT(storage, transform_t);
 	REGISTER_COMPONENT(storage, collider_t);
@@ -37,6 +39,19 @@ initStorage(storage_t *storage)
 void
 loadScene(storage_t *storage)
 {
+	bitset_t s1 = bitarena_at(&storage->objectSignatures, 0);
+	bitset_t s2 = bitarena_at(&storage->objectSignatures, 1);
+
+	bitset_set(s1, 9);
+	bitset_set(s2, 9);
+
+	bitset_print(s1);
+	bitset_print(s2);
+
+	bitset_t sAnd = bitset_and(s1, s2);
+	printf("Bitset is zero: %i\n", bitset_isZero(sAnd));
+	printf("Bitset is equals: %i\n", bitset_equals(s1, s2));
+	
 	entity_t e1 = createEntity(storage);
 	transform_t *t1 = GET_COMPONENT(storage, transform_t, e1);
 	t1->x = 13;
diff --git a/src/storage.h b/src/storage.h
index 3989c4a..f7f5cd9 100644
--- a/src/storage.h
+++ b/src/storage.h
@@ -12,6 +12,9 @@
 #define MAX_COMPONENTS 32
 #endif
 
+#define BITSET_BYTES (MAX_COMPONENTS / 8)
+#include "bitset.h"
+
 #define GET_COMPONENT(storage, componentType, idx) (componentType *) internal_getComponent(storage, idx, #componentType)
 #define REGISTER_COMPONENT(storage, componentType) internal_registerComponent(storage, #componentType, sizeof(componentType))
 #define ADD_COMPONENT(storage, idx, componentType) internal_addComponent(storage, idx, #componentType)
@@ -30,6 +33,7 @@ typedef struct
 	unsigned int componentsStored;
 	unsigned int objectsStored;
 	component_pair_t *objects;
+	bitarena_t objectSignatures;
 } storage_t;
 
 component_pair_t * // NULL if pair is not found
-- 
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