Memory Allocation

About

The MAXON API provides tools to safely allocate new memory. Typically it is not needed to allocate raw memory, structures like maxon::BaseArray should be used instead (see BaseArray Manual). Memory is allocated using different allocators.

For object creation see Entity Creation.

Allocation

These macros allocate raw memory using the maxon::DefaultAllocator:

To safely handle memory one can use references, see maxon::AutoMem in References.

Alternatively one can use the finally macro to ensure the release of memory, see Finally.

// This example allocates raw memory and stores it with AutoMem.
// allocate memory
// use memory
for (maxon::Int i = 0; i < count; ++i)
data[i] = (maxon::Char)i;
// when the scope is left, maxon::AutoMem will free the memory
Py_ssize_t i
Definition: abstract.h:645
Py_ssize_t count
Definition: abstract.h:640
Definition: baseref.h:62
#define NewMemClear(T, cnt)
Definition: defaultallocator.h:204
Int64 Int
signed 32/64 bit int, size depends on the platform
Definition: apibase.h:202
char Char
signed 8 bit character
Definition: apibase.h:198
#define iferr_return
Definition: resultbase.h:1524

Memory Utility

Further memory utility tools are:

// This example allocates new memory. The memory content is written, copied and compared.
maxon::Char* data = nullptr;
maxon::Char* copy = nullptr;
finally
{
// assure release of memory at the end
DeleteMem(data);
DeleteMem(copy);
};
// allocate memory
// use memory
for (maxon::Int i = 0; i < count; ++i)
data[i] = (maxon::Char)i;
// copy data
maxon::MemCopy(copy, data, count);
// compare
const maxon::Int res = maxon::CompareMem(data, copy, count);
if (res == 0)
DiagnosticOutput("Memory blocks are identical.");
// clear memory
Py_UCS4 * res
Definition: unicodeobject.h:1113
#define DiagnosticOutput(formatString,...)
Definition: debugdiagnostics.h:170
void DeleteMem(T *&p)
Definition: defaultallocator.h:257
MAXON_ATTRIBUTE_FORCE_INLINE Int CompareMem(const void *block1, const void *block2, Int size)
Definition: defaultallocator.h:367
MAXON_ATTRIBUTE_FORCE_INLINE void SecureClearMem(volatile void *mem, Int size, UChar value=0)
Definition: defaultallocator.h:352
MAXON_ATTRIBUTE_FORCE_INLINE void MemCopy(void *dst, const void *src, Int size)
Definition: defaultallocator.h:284

Allocators

An allocator allocates and releases memory. Typically the maxon::DefaultAllocator is used. In rare cases when special memory alignment is needed, a custom allocator can be used.

If memory from the C standard lib is needed, use maxon::CStdLibAllocator.

// This example uses FixedBufferAllocator to define a BaseArray type which guarantees a certain amout of memory.
// define a BaseArray with guaranteed 1024 bytes from the stack
// create array
FixedBufferArray testArray;
// check array size
const maxon::Int size = (maxon::Int)SIZEOF(testArray);
DiagnosticOutput("Size: @", size);
// fill array
// as long as the needed size is less than 1024, no memory calls are invoked
for (maxon::Int i = 0; i < 1024; ++i)
{
testArray.Append() iferr_return;
}
Definition: basearray.h:415
Py_ssize_t size
Definition: bytesobject.h:86
#define SIZEOF(...)
Calculates the size of a datatype or element.
Definition: apibasemath.h:214

Further Reading