Refactor allocator to use offsets instead of absolute pointers

JLANG_malloc now returns size_t offsets relative to the heap buffer, making all references stable across heap growth (realloc). Object API updated accordingly: constructors return offsets, obj_print/obj_free receive (allocator, offset). Added heap auto-grow when out of space.
2026-02-15 23:16:45 +01:00
parent 5dc0946a19
commit 13c9d052a0
3 changed files with 118 additions and 100 deletions
--- a/src/main.c
+++ b/src/main.c
@@ -7,24 +7,18 @@ int main() {
  printf("memoryPtr=%p\n", allocPtr->memory);
  printf("size=%zu\n", allocPtr->size);

-  // Create object
-  Object *intVar1 = obj_new_int(allocPtr, 66);
-  obj_print(intVar1);
-
-  Object *stringVar1 = obj_new_string(allocPtr, "\nHello world!\n");
-  obj_print(stringVar1);
+  size_t stringVar1 = obj_new_string(allocPtr, "\nHello world!\n");
+  obj_print(allocPtr, stringVar1);

  JLANG_visualize(allocPtr);

-  for (int i = 0; i < 10; i++) {
-    Object *intVar1 = obj_new_int(allocPtr, 66);
-    obj_print(intVar1);
+  // obj_free(allocPtr, stringVar1);
+
+  for (int i = 0; i < 20; i++) {
+    obj_new_string(allocPtr, "FFFFFFFFFFFFFF");
  }

-  obj_free(allocPtr, intVar1);
-  void* newPtr = JLANG_malloc(allocPtr, 8);
-
-  obj_print(stringVar1);
+  obj_print(allocPtr, stringVar1);
  JLANG_visualize(allocPtr);
  return 0;
 }
--- a/src/memory/allocator.h
+++ b/src/memory/allocator.h
@@ -58,7 +58,7 @@ size_t JLANG_used(void *ptr) {
  // Iterate memory parsing only metadata
  JLANG_metadata *currentHeader = (JLANG_metadata *)allocPtr->memory;
  size_t used = 0;
-  while (currentHeader->in_use != 0 && used < allocPtr->size) {
+  while (currentHeader->size != 0 && used < allocPtr->size) {
    used += sizeof(JLANG_metadata) + currentHeader->size;

    // Current block is in_use, jump to next block
@@ -76,7 +76,7 @@ void *JLANG_last_free(void *ptr) {
  // Iterate memory parsing only metadata
  JLANG_metadata *currentHeader = (JLANG_metadata *)allocPtr->memory;
  size_t used = 0;
-  while (currentHeader->in_use != 0 && used < allocPtr->size) {
+  while (currentHeader->size != 0 && used < allocPtr->size) {
    used += sizeof(JLANG_metadata) + currentHeader->size;

    // Current block is in_use, jump to next block
@@ -88,7 +88,9 @@ void *JLANG_last_free(void *ptr) {
  return currentHeader;
 }

-void *JLANG_malloc(void *ptr, size_t size) {
+// JLANG_malloc devuelve un offset a la memoria del heap. No un absoluto a la
+// memoria del proceso
+size_t JLANG_malloc(void *ptr, size_t size) {
  JLANG_memory_allocator *allocPtr = (JLANG_memory_allocator *)ptr;

  // 1. Hay bloques disponibles??
@@ -101,16 +103,42 @@ void *JLANG_malloc(void *ptr, size_t size) {
    freeHeader->size = size;
    freeHeader->in_use = 1;

-    return (char *)freeHeader + sizeof(JLANG_metadata);
+    void *payloadPtr = (char *)freeHeader + sizeof(JLANG_metadata);
+
+    return (char *)payloadPtr - allocPtr->memory;
  }

-  return NULL; // TODO
+  /*
+    Se necesita más espacio..
+    De momento vamos a pedir otro array más grande y liberar el antiguo
+    Mantenemos toda la memoria contigua
+  */
+
+  int newSize = allocPtr->size + 1024;
+  char *newBuffer = (char *)malloc(newSize); // Otro 1KB
+  memset(newBuffer, 0, newSize);
+  memcpy(newBuffer, allocPtr->memory,
+         allocPtr->size); // Copiamos al nuevo buffer
+
+  allocPtr->size = newSize;
+
+  free(allocPtr->memory);       // Liberamos el buffer antiguo
+  allocPtr->memory = newBuffer; // Seteamos el nuevo buffer
+
+  JLANG_metadata *freeHeader = (JLANG_metadata *)JLANG_last_free(ptr);
+  freeHeader->size = size;
+  freeHeader->in_use = 1;
+
+  void *payloadPtr = (char *) freeHeader + sizeof(JLANG_metadata);
+  return (char *)payloadPtr - allocPtr->memory;
 }

-void JLANG_free(void *ptr, void *blockPtr) {
+void JLANG_free(void *ptr, size_t blockOffset) {
  JLANG_memory_allocator *allocPtr = (JLANG_memory_allocator *)ptr;

  // Get block header
+  void *blockPtr = allocPtr->memory + blockOffset;
+
  JLANG_metadata *blockHeader =
      (JLANG_metadata *)((char *)blockPtr - sizeof(JLANG_metadata));

--- a/src/objects/object.h
+++ b/src/objects/object.h
@@ -1,101 +1,97 @@
 #include "../memory/allocator.h"

-typedef enum
-{
-    OBJ_INT,
-    OBJ_FLOAT,
-    OBJ_STRING,
-    OBJ_LIST,
-    OBJ_NONE
-} ObjectType;
+#define JLANG_RESOLVE(alloc, offset)                                           \
+  ((void *)(((JLANG_memory_allocator *)(alloc))->memory + (offset)))

-typedef struct Object
-{
-    ObjectType type;
-    union
-    {
-        int int_val;
-        double float_val;
-        struct
-        {
-            char *chars;
-            int length;
-        } string_val;
-        struct
-        {
-            struct Object **items;
-            int count;
-            int capacity;
-        } list_val;
-    } data;
+typedef enum { OBJ_INT, OBJ_FLOAT, OBJ_STRING, OBJ_LIST, OBJ_NONE } ObjectType;
+
+typedef struct Object {
+  ObjectType type;
+  union {
+    int int_val;
+    double float_val;
+    struct {
+      size_t chars;
+      int length;
+    } string_val;
+    struct {
+      struct Object **items;
+      int count;
+      int capacity;
+    } list_val;
+  } data;
 } Object;

-Object *obj_new_int(void *allocator, int value)
-{
-    Object *objPtr = (Object *)JLANG_malloc(allocator, sizeof(Object));
-    objPtr->type = OBJ_INT;
-    objPtr->data.int_val = value;
-    return objPtr;
+size_t obj_new_int(void *allocator, int value) {
+  // Object *objPtr = (Object *)JLANG_malloc(allocator, sizeof(Object));
+  size_t offset = JLANG_malloc(allocator, sizeof(Object));
+  Object *objPtr = (Object *)JLANG_RESOLVE(allocator, offset);
+  objPtr->type = OBJ_INT;
+  objPtr->data.int_val = value;
+  return offset;
 }

-Object *obj_new_float(void *allocator, float value)
-{
-    Object *objPtr = (Object *)JLANG_malloc(allocator, sizeof(Object));
-    objPtr->type = OBJ_FLOAT;
-    objPtr->data.float_val = value;
-    return objPtr;
+size_t obj_new_float(void *allocator, float value) {
+  size_t offset = JLANG_malloc(allocator, sizeof(Object));
+  Object *objPtr = (Object *)JLANG_RESOLVE(allocator, offset);
+  objPtr->type = OBJ_FLOAT;
+  objPtr->data.float_val = value;
+  return offset;
 }

-Object *obj_new_string(void *allocator, const char *str)
-{
-    Object *objPtr = (Object *)JLANG_malloc(allocator, sizeof(Object));
-    objPtr->type = OBJ_STRING;
+size_t obj_new_string(void *allocator, const char *str) {
+  size_t offset = JLANG_malloc(allocator, sizeof(Object));
+  Object *objPtr = (Object *)JLANG_RESOLVE(allocator, offset);

-    int len = strlen(str);
-    char *buffer = (char *)JLANG_malloc(allocator, len + 1);
-    memcpy(buffer, str, len + 1);
+  objPtr->type = OBJ_STRING;

-    objPtr->data.string_val.chars = buffer;
-    objPtr->data.string_val.length = len;
+  int len = strlen(str);

-    return objPtr;
+  // !! CUIDADO CON ESTE DOBLE MALLOC SI DISPARA EL GROW !!
+  size_t bufferOffset = JLANG_malloc(allocator, len + 1);
+  char *buffer = (char *)JLANG_RESOLVE(allocator, bufferOffset);
+  memcpy(buffer, str, len + 1);
+
+  objPtr->data.string_val.chars = bufferOffset;
+  objPtr->data.string_val.length = len;
+
+  return offset;
 }

-Object *obj_new_list(void *allocator)
-{
-    Object *objPtr = (Object *)JLANG_malloc(allocator, sizeof(Object));
-    objPtr->type = OBJ_LIST;
-    return objPtr;
+size_t obj_new_list(void *allocator) {
+  size_t offset = JLANG_malloc(allocator, sizeof(Object));
+  Object *objPtr = (Object *)JLANG_RESOLVE(allocator, offset);
+  objPtr->type = OBJ_LIST;
+  return offset;
 }

-void obj_free(void *allocator, Object* obj) {
-    if (obj->type == OBJ_STRING) {
-        JLANG_free(allocator, obj->data.string_val.chars);
-    }
+void obj_free(void *allocator, size_t offset) {
+  // if (obj->type == OBJ_STRING) {
+  //  JLANG_free(allocator, obj->data.string_val.chars);
+  // }

-    JLANG_free(allocator, obj);
+  JLANG_free(allocator, offset);
 }

-void obj_print(Object *obj)
-{
-    switch (obj->type)
-    {
-    case OBJ_INT:
-        printf("%d", obj->data.int_val);
-        break;
-    case OBJ_FLOAT:
-        printf("%f", obj->data.float_val);
-        break;
-    case OBJ_LIST:
-        for (int i = 0; i < obj->data.list_val.count; i++)
-        {
-            obj_print(obj->data.list_val.items[i]);
-        }
-        break;
-    case OBJ_STRING:
-        printf("%s", obj->data.string_val.chars);
-        break;
-    default:
-        break;
-    }
+void obj_print(void *allocator, size_t offset) {
+  Object *obj = (Object *)JLANG_RESOLVE(allocator, offset);
+
+  switch (obj->type) {
+  case OBJ_INT:
+    printf("%d", obj->data.int_val);
+    break;
+  case OBJ_FLOAT:
+    printf("%f", obj->data.float_val);
+    break;
+    //  case OBJ_LIST:
+    //    for (int i = 0; i < obj->data.list_val.count; i++) {
+    //      obj_print(obj->data.list_val.items[i]);
+    //    }
+    //    break;
+  case OBJ_STRING:
+    printf("%s", (char *)JLANG_RESOLVE(allocator, obj->data.string_val.chars));
+    break;
+  default:
+    break;
+  }
 }