1 files changed, 116 insertions, 0 deletions
diff --git a/BumpAlloc.c b/BumpAlloc.c
new file mode 100644
index 0000000..327bfd5
--- /dev/null
+++ b/BumpAlloc.c
@@ -0,0 +1,116 @@
+#include "BumpAlloc.h"
+#include "Types.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+struct BumpArena {
+    void* memory;
+    usize size;
+    usize top;
+};
+
+BumpArena
+Bcreate(usize size) {
+    struct BumpArena *b = malloc(sizeof(struct BumpArena));
+    b->memory = malloc(size);
+    b->size = size;
+    b->top = 0;
+
+    return b;
+}
+
+Result
+Bdestroy(BumpArena bp) {
+    if (NULL == bp)
+        return R_Uninitialized;
+
+    struct BumpArena b = *(struct BumpArena*)bp;
+
+    if (NULL == b.memory)
+        return R_Uninitialized;
+
+    free(b.memory);
+    b.memory = NULL;
+    b.size = b.top = 0;
+
+    return R_Ok;
+}
+
+static inline usize*
+top_size(struct BumpArena* b) {
+    return (usize*)(b->memory + b->top);
+}
+
+void*
+Balloc(BumpArena bp, usize size) {
+    if (bp == NULL || size == 0)
+        return NULL;
+
+    struct BumpArena *b = (struct BumpArena*)bp;
+
+    if (size + b->top + sizeof(usize) > b->size)
+        return NULL;
+
+    if (b->top > 0)
+        b->top += sizeof(usize);
+    usize start = b->top;
+
+    b->top += size;
+    // Keep allocated memory size at the end of every allocation
+    *top_size(b) = size;
+
+    return b->memory + start;
+}
+
+int
+Bresizeable(BumpArena bp, void* ptr) {
+    if (NULL == bp)
+        return 0;
+
+    struct BumpArena *b = (struct BumpArena*)bp;
+
+    return b->memory + b->top - *top_size(b) <= ptr &&
+           ptr < b->memory + b->top;
+}
+
+Result
+Bresize(BumpArena bp, usize size) {
+    if (NULL == bp)
+        return R_Uninitialized;
+
+    struct BumpArena *b = (struct BumpArena*)bp;
+
+    if (size == 0) {
+        Bfree(bp);
+        return R_Ok;
+    }
+
+    usize last_size = *top_size(b);
+    usize start = b->top - last_size;
+    if (start > 0)
+        start -= sizeof(usize);
+
+    if (start + size + sizeof(usize) > b->size)
+        return R_OutOfBounds;
+
+    b->top += size;
+    *top_size(b) = size;
+
+    return R_Ok;
+}
+
+Result
+Bfree(BumpArena bp) {
+    if (NULL == bp)
+        return R_Uninitialized;
+
+    struct BumpArena *b = (struct BumpArena*)bp;
+
+    if (b->top > 0) {
+        b->top -= *top_size(b);
+        if (b->top > 0)
+            b->top -= sizeof(usize);
+    }
+
+    return R_Ok;
+}