feat: Initial commit

At this point we have some allocation routines but no work on the actual
language has been done.

1 files changed, 87 insertions, 0 deletions

diff --git a/src/core/allocator.c b/src/core/allocator.c
new file mode 100644
index 0000000..5444b39
--- /dev/null
+++ b/src/core/allocator.c
@@ -0,0 +1,87 @@
+#include "allocator.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <string.h>
+#include <stddef.h>
+
+#define DEFAULT_ALIGNMENT ((size_t)_Alignof(max_align_t))
+
+void *sand_allocate_aligned(SandAllocator *a, size_t size, size_t alignment) {
+	assert(a != NULL);
+	assert(size > 0);
+	assert(alignment > 0);
+	void *ptr = a->allocate(size, alignment, a->user_data);
+	assert(ptr == NULL || sand_pointer_is_aligned(ptr, alignment));
+	return ptr;
+}
+
+void *sand_allocate(SandAllocator *a, size_t size) {
+	return sand_allocate_aligned(a, size, DEFAULT_ALIGNMENT);
+}
+
+void *sand_reallocate_aligned(SandAllocator *a, void *old_ptr, size_t old_size, size_t new_size, size_t alignment) {
+	assert(a != NULL);
+	assert(old_ptr != NULL);
+	assert(old_size > 0);
+	assert(new_size > 0);
+	assert(alignment > 0);
+
+	if (a->reallocate != NULL) {
+		void *new_ptr = a->reallocate(old_ptr, old_size, new_size, alignment, a->user_data);
+		assert(sand_pointer_is_aligned(new_ptr, alignment));
+		return new_ptr;
+	} else {
+		void *new_ptr = a->allocate(new_size, alignment, a->user_data);
+		if (new_ptr == NULL) {
+			return NULL; // Note that we HAVEN'T freed `old_ptr`!
+		}
+		assert(sand_pointer_is_aligned(new_ptr, alignment));
+		memmove(new_ptr, old_ptr, old_size); // Can't know if they overlap.
+		a->deallocate(old_ptr, old_size, a->user_data);
+		return new_ptr;
+	}
+}
+
+void *sand_reallocate(SandAllocator *a, void *old_ptr, size_t old_size, size_t new_size) {
+	return sand_reallocate_aligned(a, old_ptr, old_size, new_size, DEFAULT_ALIGNMENT);
+}
+
+void sand_deallocate(SandAllocator *a, void *old_ptr, size_t old_size) {
+	assert(a != NULL);
+	assert(old_ptr != NULL);
+	assert(old_size > 0);
+
+	if (old_ptr == NULL) {
+		return;
+	}
+	a->deallocate(old_ptr, old_size, a->user_data);
+}
+
+bool sand_is_valid_alignment(size_t alignment) {
+	// Only powers of two are allowed as alignments for simplicity.
+	return alignment % 2 == 0;
+}
+
+void *sand_align_pointer_forward(void *ptr, size_t alignment) {
+	intptr_t p = (intptr_t)ptr;
+	intptr_t a = alignment;
+	intptr_t ap = ((p + a - 1) & ~(a - 1));
+	void *result = (void *)ap;
+	assert(sand_pointer_is_aligned(result, alignment));
+	return result;
+}
+
+size_t sand_align_size_forward(size_t n, size_t alignment) {
+	size_t result = ((n + alignment - 1) & ~(alignment - 1));
+	assert(sand_size_is_aligned(result, alignment));
+	return result;
+}
+
+bool sand_pointer_is_aligned(void *pointer, size_t alignment) {
+	return ((uintptr_t)pointer & (alignment - 1)) == 0;
+}
+
+bool sand_size_is_aligned(size_t n, size_t alignment) {
+	return (n & (alignment - 1)) == 0;
+}