Struct hack in buffer

src/buffer.c

@@ -9,13 +9,12 @@ ds_buffer_t *ds_buffer(zend_long capacity)
 {
     php_printf("buffer: allocate capacity of " ZEND_LONG_FMT "\n", capacity);
 
-    ds_buffer_t *buffer = ecalloc(1, sizeof(ds_buffer_t));
+    ds_buffer_t *buffer = ecalloc(1, DS_BUFFER_ALLOC_SIZE(capacity));
     zend_object *object = (zend_object *) buffer;
 
     zend_object_std_init((zend_object *) buffer, ds_buffer_ce);
 
     object->handlers = &ds_buffer_handlers;
-    buffer->data     = ecalloc(capacity, sizeof(zval));
     buffer->len      = capacity;
 
     return buffer;
@@ -52,12 +51,14 @@ void ds_buffer_set(ds_buffer_t *buffer, zend_long offset, zval *value)
     ZVAL_COPY(&buffer->data[offset], value);
 }
 
-void ds_buffer_realloc(ds_buffer_t *buffer, zend_long capacity)
+ds_buffer_t *ds_buffer_realloc(ds_buffer_t *buffer, zend_long capacity)
 {
     php_printf("buffer: increase capacity to " ZEND_LONG_FMT "\n", capacity);
 
-    buffer->data = erealloc(buffer->data, capacity * sizeof(zval));
-    buffer->len  = capacity;
+    buffer      = erealloc(buffer, DS_BUFFER_ALLOC_SIZE(capacity));
+    buffer->len = capacity;
+
+    return buffer;
 }
 
 ds_buffer_t *ds_buffer_create_copy(ds_buffer_t *src)

src/buffer.h

@@ -8,13 +8,19 @@
  */
 #define DS_ZVAL_GET_BUFFER(z) ((ds_buffer_t *) (Z_OBJ_P(z)))
 
+/**
+ * Allocation length for the buffer struct and data.
+ */
+#define DS_BUFFER_ALLOC_SIZE(capacity) \
+    (sizeof(ds_buffer_t) + sizeof(zval) * (capacity - 1))
+
 /**
  * Buffer object.
  */
 typedef struct ds_buffer {
     zend_object std;
-    zval *data;
     zend_long len;
+    zval data[1];
 } ds_buffer_t;
 
 /**
@@ -50,7 +56,7 @@ ds_buffer_t *ds_buffer_create_copy(ds_buffer_t *src);
 /**
  * Reallocates the buffer to a given capacity.
  */
-void ds_buffer_realloc(ds_buffer_t *obj, zend_long capacity);
+ds_buffer_t *ds_buffer_realloc(ds_buffer_t *buffer, zend_long capacity);
 
 /**
  * Sets the array representation of a given buffer.

src/vector.c

@@ -74,7 +74,8 @@ void ds_vector_push(ds_vector_t *vector, zval *value)
 
     /* Check if we need to grow. */
     if (vector->size == buffer->len) {
-        ds_buffer_realloc(buffer, buffer->len * 2 + 1);
+        buffer = ds_buffer_realloc(buffer, buffer->len * 2 + 1);
+        DS_VECTOR_SET_BUFFER(vector, buffer);
     }
 
     ds_buffer_set(buffer, vector->size, value);