Stable vector implementation

Stable vectors will be used in the lisp runtime to implement actual
vectors, instead of using the disgusting lvec trick.  This way we at
least can get attributes about the vector through one pointer hop.

alisp.h

@@ -46,6 +46,18 @@ typedef struct
 
 sv_t sv_copy(sv_t);
 
+/// Good ol' Dynamic Arrays
+typedef struct Vector
+{
+  u64 size, capacity;
+  void *data;
+} vec_t;
+
+#define VEC_MULT 2
+void vec_free(vec_t *);
+void vec_ensure_free(vec_t *, u64);
+void vec_append(vec_t *, void *, u64);
+void vec_clone(vec_t *, vec_t *);
 
 /// Inlined Dynamic arrays
 typedef struct InlineVector

build.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env sh
 
 CFLAGS="-Wall -Wextra -std=c11 -ggdb -fsanitize=address -fsanitize=undefined"
-SRC="ivec.c symtable.c tag.c constructor.c sys.c main.c"
+SRC="vec.c ivec.c symtable.c tag.c constructor.c sys.c main.c"
 OUT="alisp.out"
 
 set -xe

vec.c

@@ -0,0 +1,57 @@
+/* Copyright (C) 2025 Aryadev Chavali
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the Unlicense
+ * for details.
+
+ * You may distribute and modify this code under the terms of the
+ * Unlicense, which you should have received a copy of along with this
+ * program.  If not, please go to <https://unlicense.org/>.
+
+ * Created: 2025-08-20
+ * Description: Stable Vector implementation
+ */
+
+#include <malloc.h>
+#include <string.h>
+
+#include "./alisp.h"
+
+void vec_free(vec_t *vec)
+{
+  if (!vec)
+    return;
+  if (vec->data)
+    free(vec->data);
+  memset(vec, 0, sizeof(*vec));
+}
+
+void vec_ensure_free(vec_t *vec, u64 size)
+{
+  if (!vec)
+    return;
+  if (vec->capacity - vec->size < size)
+  {
+    vec->capacity = MAX(vec->capacity * VEC_MULT, vec->size + size);
+    vec->data     = realloc(vec->data, vec->capacity);
+  }
+}
+
+void vec_append(vec_t *vec, void *ptr, u64 size)
+{
+  if (!vec)
+    return;
+  vec_ensure_free(vec, size);
+  memcpy(vec->data + vec->size, ptr, size);
+  vec->size += size;
+}
+
+void vec_clone(vec_t *dest, vec_t *src)
+{
+  if (!src || !dest)
+    return;
+  dest       = src;
+  dest->data = calloc(1, dest->capacity);
+  memcpy(dest->data, src->data, src->size);
+}