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-rw-r--r--source/kit/allocator.c201
1 files changed, 201 insertions, 0 deletions
diff --git a/source/kit/allocator.c b/source/kit/allocator.c
new file mode 100644
index 0000000..e1446ac
--- /dev/null
+++ b/source/kit/allocator.c
@@ -0,0 +1,201 @@
+#include "allocator.h"
+
+#include <assert.h>
+#include <string.h>
+
+#ifndef KIT_DISABLE_SYSTEM_MALLOC
+# include <stdlib.h>
+#endif
+
+static void *kit_allocate_default_(i32 request, i64 size,
+ i64 previous_size, void *pointer) {
+#ifndef KIT_DISABLE_SYSTEM_MALLOC
+ switch (request) {
+ case KIT_ALLOCATE:
+ case KIT_ALLOCATE_ZERO: {
+ assert(size >= 0);
+ assert(previous_size == 0);
+ assert(pointer == NULL);
+
+ if (size <= 0)
+ return NULL;
+
+ void *p = malloc(size);
+
+ if (p != NULL && request == KIT_ALLOCATE_ZERO)
+ memset(p, 0, size);
+
+ return p;
+ }
+
+ case KIT_REALLOCATE:
+ case KIT_REALLOCATE_ZERO: {
+ assert(size >= 0);
+ assert(previous_size != 0 || pointer == NULL);
+ assert(previous_size == 0 || pointer != NULL);
+
+ if (previous_size == 0 && pointer != NULL)
+ return NULL;
+ if (previous_size != 0 && pointer == NULL)
+ return NULL;
+ if (size == previous_size)
+ return pointer;
+
+ u8 *p = NULL;
+
+ if (size > 0) {
+ p = (u8 *) malloc(size);
+
+ if (p != NULL) {
+ if (size > 0 && previous_size > 0)
+ memcpy(p, pointer,
+ size < previous_size ? size : previous_size);
+ if (request == KIT_REALLOCATE_ZERO && size > previous_size)
+ memset(p + previous_size, 0, size - previous_size);
+ }
+ }
+
+ free(pointer);
+
+ return p;
+ }
+
+ case KIT_DEALLOCATE:
+ assert(size == 0);
+ assert(pointer != NULL);
+ if (pointer != NULL)
+ free(pointer);
+ return NULL;
+
+ case KIT_DEALLOCATE_ALL:
+ // Do nothing.
+ //
+ return NULL;
+
+ default:;
+ }
+#endif
+
+ assert(0);
+ return NULL;
+}
+
+static void *kit_allocate_from_buffer_(kit_allocator_t *alloc,
+ i32 request, i64 size,
+ i64 previous_size,
+ void *pointer) {
+ assert(alloc != NULL);
+ assert(pointer == NULL || pointer < alloc->data);
+
+ if (alloc == NULL)
+ return NULL;
+
+ switch (request) {
+ case KIT_ALLOCATE:
+ case KIT_ALLOCATE_ZERO: {
+ assert(size >= 0);
+ assert(previous_size == 0);
+ assert(pointer == NULL);
+
+ if (size <= 0)
+ return NULL;
+
+ if (alloc->size < size)
+ return NULL;
+
+ void *p = alloc->data;
+ alloc->bytes += size;
+ alloc->size -= size;
+
+ if (request == KIT_ALLOCATE_ZERO)
+ memset(p, 0, size);
+
+ return p;
+ }
+
+ case KIT_REALLOCATE:
+ case KIT_REALLOCATE_ZERO: {
+ assert(size >= 0);
+ assert(previous_size != 0 || pointer == NULL);
+ assert(previous_size == 0 || pointer != NULL);
+
+ if (size <= 0)
+ return NULL;
+ if (size <= previous_size)
+ return pointer;
+ if (previous_size == 0 && pointer != NULL)
+ return NULL;
+ if (previous_size != 0 && pointer == NULL)
+ return NULL;
+
+ if ((u8 *) pointer + previous_size == alloc->data) {
+ if (alloc->size < size - previous_size)
+ return NULL;
+ alloc->bytes += size - previous_size;
+ alloc->size -= size - previous_size;
+ return pointer;
+ }
+
+ if (alloc->size < size)
+ return NULL;
+
+ u8 *p = alloc->bytes;
+ alloc->bytes += size;
+ alloc->size -= size;
+
+ if (previous_size > 0)
+ memcpy(p, pointer, previous_size);
+ if (request == KIT_REALLOCATE_ZERO)
+ memset(p + previous_size, 0, size - previous_size);
+
+ return p;
+ }
+
+ case KIT_DEALLOCATE:
+ case KIT_DEALLOCATE_ALL: return NULL;
+
+ default:;
+ }
+
+ assert(0);
+ return NULL;
+}
+#ifndef KIT_ENABLE_CUSTOM_ALLOC_DISPATCH
+void *kit_alloc_dispatch(kit_allocator_t *alloc, i32 request,
+ i64 size, i64 previous_size, void *pointer) {
+ if (alloc == NULL)
+ return kit_allocate_default_(request, size, previous_size,
+ pointer);
+
+ switch (alloc->type) {
+ case KIT_ALLOC_TYPE_DEFAULT:
+ return kit_allocate_default_(request, size, previous_size,
+ pointer);
+
+ case KIT_ALLOC_TYPE_BUFFER:
+ return kit_allocate_from_buffer_(alloc, request,
+ // alignment
+ ((size + 7) / 8) * 8,
+ previous_size, pointer);
+
+ default:;
+ }
+
+ return NULL;
+}
+#endif
+
+kit_allocator_t kit_alloc_default(void) {
+ kit_allocator_t alloc = { .type = KIT_ALLOC_TYPE_DEFAULT,
+ .size = 0,
+ .data = NULL };
+ return alloc;
+}
+
+kit_allocator_t kit_alloc_buffer(i64 size, void *buffer) {
+ kit_allocator_t alloc = { .type = KIT_ALLOC_TYPE_BUFFER,
+ .size = size,
+ .data = buffer };
+
+ return alloc;
+}