1 files changed, 41 insertions, 9 deletions
diff --git a/src/bumpptr_alloc.c b/src/bumpptr_alloc.c
index 77a11d9..ee2928a 100644
--- a/src/bumpptr_alloc.c
+++ b/src/bumpptr_alloc.c
@@ -1,16 +1,52 @@
-#include <errno.h>  /* TODO: set errno */
+#include <assert.h>
+#include <errno.h>
 #include <stddef.h> /* NULL, size_t */
 #include <stdint.h> /* uintptr_t */
 #include <stdio.h>  /* fprintf */
-
-#include "bump_alloc.h"
+#include <sys/mman.h> /* mmap */
 
 #define MIN_ALIGNMENT 16
 
-#ifdef __cplusplus
-extern "C" {
+#ifndef MEMSIZE
+#define MEMSIZE 1024*4*1024*1024l
 #endif
 
+#define unlikely(x)     __builtin_expect((x),0)
+
+typedef struct bumpptr {
+	uintptr_t end;
+	uintptr_t ptr;
+} bumpptr_t;
+
+__thread bumpptr_t* tsd = NULL;
+
+static inline void* bump_up(size_t size, size_t align) {
+	assert(align % 2 == 0);
+
+	if (unlikely(tsd == NULL)) {
+		void* mem_start = mmap(NULL, MEMSIZE, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, -1, 0);
+		if(mem_start == MAP_FAILED) {
+			perror("mmap");
+			return NULL;
+		}
+		tsd = (bumpptr_t*)mem_start;
+		tsd->ptr = (uintptr_t)mem_start + sizeof(bumpptr_t);
+		tsd->end = (uintptr_t)mem_start + MEMSIZE;
+	}
+
+	// align ptr;
+	uintptr_t aligned = (tsd->ptr + align - 1) & ~(align - 1);
+
+	uintptr_t new_ptr = aligned + size;
+	if (new_ptr > tsd->end) {
+		errno = ENOMEM;
+		return NULL;
+	} else {
+		tsd->ptr = new_ptr;
+		return (void*)aligned;
+	}
+}
+
 void* malloc(size_t size) {
 	return bump_up(size, MIN_ALIGNMENT);
 }
@@ -26,7 +62,3 @@ void malloc_stats() {
 	fprintf(stderr, "Bump pointer allocator by muhq\n");
 	fprintf(stderr, "Memsize: %zu, start address: %p, bump pointer %p\n", MEMSIZE, tsd, tsd->ptr);
 }
-
-#ifdef __cplusplus
-}
-#endif