diff --git a/cs_vm.cc b/cs_vm.cc
index 4290de5..9bfc559 100644
--- a/cs_vm.cc
+++ b/cs_vm.cc
@@ -3,6 +3,8 @@
 
 #include <limits.h>
 
+#include <ostd/memory.hh>
+
 namespace cscript {
 
 static inline ostd::Uint32 const *forcecode(CsState &cs, TaggedValue &v) {
@@ -827,10 +829,9 @@ static ostd::Uint32 const *runcode(CsState &cs, ostd::Uint32 const *code, Tagged
                 (cs).stack = &aliaslink; \
                 if(!id->code) id->code = reinterpret_cast<Bytecode *>(compilecode(cs, id->get_str())); \
                 ostd::Uint32 *codep = reinterpret_cast<ostd::Uint32 *>(id->code); \
-                codep[0] += 0x100; \
+                bcode_incr(codep); \
                 runcode((cs), codep+1, (result)); \
-                codep[0] -= 0x100; \
-                if(int(codep[0]) < 0x100) delete[] codep; \
+                bcode_decr(codep); \
                 (cs).stack = aliaslink.next; \
                 (cs).identflags = oldflags; \
                 for(int i = 0; i < callargs; i++) \
@@ -1094,7 +1095,7 @@ bool CsState::run_bool(Ident *id, TvalRange args) {
 
 bool CsState::run_file(ostd::ConstCharRange fname) {
     ostd::ConstCharRange oldsrcfile = src_file, oldsrcstr = src_str;
-    char *buf = nullptr;
+    ostd::Box<char[]> buf;
     ostd::Size len;
 
     ostd::FileStream f(fname, ostd::StreamMode::read);
@@ -1102,19 +1103,17 @@ bool CsState::run_file(ostd::ConstCharRange fname) {
         return false;
 
     len = f.size();
-    buf = new char[len + 1];
-    if (f.get(buf, len) != len) {
-        delete[] buf;
+    buf = ostd::make_box<char[]>(len + 1);
+    if (!buf || f.get(buf.get(), len) != len) {
         return false;
     }
     buf[len] = '\0';
 
     src_file = fname;
-    src_str = ostd::ConstCharRange(buf, len);
-    run_int(buf);
+    src_str = ostd::ConstCharRange(buf.get(), len);
+    run_int(src_str);
     src_file = oldsrcfile;
     src_str = oldsrcstr;
-    delete[] buf;
     return true;
 }
 
diff --git a/cs_vm.hh b/cs_vm.hh
index 0f93b43..c07067d 100644
--- a/cs_vm.hh
+++ b/cs_vm.hh
@@ -211,6 +211,17 @@ ostd::String floatstr(float v);
 
 bool cs_check_num(ostd::ConstCharRange s);
 
+static inline void bcode_incr(ostd::Uint32 *bc) {
+    *bc += 0x100;
+}
+
+static inline void bcode_decr(ostd::Uint32 *bc) {
+    *bc -= 0x100;
+    if (ostd::Int32(*bc) < 0x100) {
+        delete[] bc;
+    }
+}
+
 } /* namespace cscript */
 
 #endif /* LIBCUBESCRIPT_CS_VM_HH */
diff --git a/cubescript.cc b/cubescript.cc
index fc741ec..8388390 100644
--- a/cubescript.cc
+++ b/cubescript.cc
@@ -616,8 +616,7 @@ void Ident::get_cval(TaggedValue &v) const {
 void Ident::clean_code() {
     ostd::Uint32 *bcode = reinterpret_cast<ostd::Uint32 *>(code);
     if (bcode) {
-        bcode[0] -= 0x100;
-        if (int(bcode[0]) < 0x100) delete[] bcode;
+        bcode_decr(bcode);
         code = nullptr;
     }
 }
@@ -2111,7 +2110,7 @@ ostd::Uint32 *compilecode(CsState &cs, ostd::ConstCharRange str) {
     gs.gen_main(str);
     ostd::Uint32 *code = new ostd::Uint32[gs.code.size()];
     memcpy(code, gs.code.data(), gs.code.size() * sizeof(ostd::Uint32));
-    code[0] += 0x100;
+    bcode_incr(code);
     return code;
 }
 
@@ -2119,16 +2118,16 @@ static void bcode_ref(ostd::Uint32 *code) {
     if (!code) return;
     switch (*code & CODE_OP_MASK) {
     case CODE_START:
-        *code += 0x100;
+        bcode_incr(code);
         return;
     }
     switch (code[-1]&CODE_OP_MASK) {
     case CODE_START:
-        code[-1] += 0x100;
+        bcode_incr(&code[-1]);
         break;
     case CODE_OFFSET:
         code -= int(code[-1] >> 8);
-        *code += 0x100;
+        bcode_incr(code);
         break;
     }
 }
@@ -2137,19 +2136,16 @@ static void bcode_unref(ostd::Uint32 *code) {
     if (!code) return;
     switch (*code & CODE_OP_MASK) {
     case CODE_START:
-        *code -= 0x100;
-        if (int(*code) < 0x100) delete[] code;
+        bcode_decr(code);
         return;
     }
     switch (code[-1]&CODE_OP_MASK) {
     case CODE_START:
-        code[-1] -= 0x100;
-        if (int(code[-1]) < 0x100) delete[] &code[-1];
+        bcode_decr(&code[-1]);
         break;
     case CODE_OFFSET:
         code -= int(code[-1] >> 8);
-        *code -= 0x100;
-        if (int(*code) < 0x100) delete[] code;
+        bcode_decr(code);
         break;
     }
 }