Bump allocator

bump.c

@@ -0,0 +1,59 @@
+#include <assert.h>
+#include <limits.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#define BUFSIZE (1024)
+static uint8_t some_large_buf[BUFSIZE] = {0};
+
+typedef struct {
+    uint8_t *buf;
+    size_t   buflen;
+    size_t   bufptr;
+} fast_alloc_t;
+
+void *fast_alloc(fast_alloc_t *fa, size_t s) {
+    if (fa->bufptr + s > fa->buflen) {
+        return NULL;
+    }
+    void *p = fa->buf + fa->bufptr;
+    fa->bufptr += s;
+    return p;
+}
+
+void fast_alloc_init(fast_alloc_t *fa, uint8_t *buf, size_t buflen) {
+    fa->buf = buf;
+    fa->buflen = buflen;
+    fa->bufptr = 0;
+}
+
+void fast_alloc_wipe(fast_alloc_t *fa) {
+    fa->bufptr = 0;
+    memset(fa->buf, 0, fa->buflen);
+}
+
+int main(void) {
+    fast_alloc_t fa = {0};
+    fast_alloc_init(&fa, some_large_buf, BUFSIZE);
+
+    int *a = fast_alloc(&fa, sizeof(int));
+    *a = 10;
+
+    int *b = fast_alloc(&fa, sizeof(int));
+    *b = INT_MAX;
+
+    printf("Number: %d\n", *a);
+    printf("Number: %d\n", *b);
+    assert(*a == 10);
+    assert(*b == INT_MAX);
+
+    fast_alloc_wipe(&fa);
+
+    printf("Number: %d\n", *a);
+    printf("Number: %d\n", *b);
+    assert(*a != 10);
+    assert(*b != INT_MAX);
+
+    printf("All ok!\n");
+}