diff --git a/src/cs_gen.cc b/src/cs_gen.cc
index 265644f..6f549ed 100644
--- a/src/cs_gen.cc
+++ b/src/cs_gen.cc
@@ -198,7 +198,7 @@ static inline void compileunescapestr(cs_gen_state &gs) {
     memset(&buf[len], 0, sizeof(uint32_t) - len % sizeof(uint32_t));
     gs.code.back() |= len << 8;
     uint32_t *ubuf = reinterpret_cast<uint32_t *>(buf);
-    gs.code.insert(gs.code.end(), ubuf, ubuf + (len / sizeof(uint32_t) + 1));
+    gs.code.append(ubuf, ubuf + (len / sizeof(uint32_t) + 1));
     delete[] buf;
 }
 
@@ -496,7 +496,7 @@ static bool compileblockstr(cs_gen_state &gs, ostd::string_range str) {
 done:
     memset(&buf[len], '\0', sizeof(uint32_t) - len % sizeof(uint32_t));
     uint32_t *ubuf = reinterpret_cast<uint32_t *>(buf);
-    gs.code.insert(gs.code.end(), ubuf, ubuf + (len / sizeof(uint32_t) + 1));
+    gs.code.append(ubuf, ubuf + (len / sizeof(uint32_t) + 1));
     gs.code[startc] |= len << 8;
     delete[] buf;
     return true;
diff --git a/src/cs_util.hh b/src/cs_util.hh
index 36a19cb..256951c 100644
--- a/src/cs_util.hh
+++ b/src/cs_util.hh
@@ -212,15 +212,31 @@ struct cs_valbuf {
     using const_reference = T const &;
 
     void reserve(std::size_t s) { buf.reserve(s); }
+    void resize(std::size_t s) { buf.resize(s); }
+
+    void append(T const *beg, T const *end) {
+        buf.insert(buf.end(), beg, end);
+    }
 
     void push_back(T const &v) { buf.push_back(v); }
+    void pop_back() { buf.pop_back(); }
 
-    size_t size() const { return buf.size(); }
+    T &back() { return buf.back(); }
+    T const &back() const { return buf.back(); }
+
+    std::size_t size() const { return buf.size(); }
+    std::size_t capacity() const { return buf.capacity(); }
 
     bool empty() const { return buf.empty(); }
 
     void clear() { buf.clear(); }
 
+    T &operator[](std::size_t i) { return buf[i]; }
+    T const &operator[](std::size_t i) const { return buf[i]; }
+
+    T *data() { return &buf[0]; }
+    T const *data() const { return &buf[0]; }
+
     std::vector<T, cs_shared_state::allocator<T>> buf;
 };
 
@@ -229,7 +245,7 @@ struct cs_charbuf: cs_valbuf<char> {
     cs_charbuf(cs_state &cs): cs_valbuf<char>(cs) {}
 
     void append(char const *beg, char const *end) {
-        buf.insert(buf.end(), beg, end);
+        cs_valbuf<char>::append(beg, end);
     }
 
     void append(ostd::string_range v) {
diff --git a/src/cs_vm.hh b/src/cs_vm.hh
index f518363..1722b49 100644
--- a/src/cs_vm.hh
+++ b/src/cs_vm.hh
@@ -128,14 +128,14 @@ struct cs_gen_state {
     cs_state &cs;
     cs_gen_state *prevps;
     bool parsing = true;
-    cs_vector<uint32_t> code;
+    cs_valbuf<uint32_t> code;
     ostd::string_range source;
     size_t current_line;
     ostd::string_range src_name;
 
     cs_gen_state() = delete;
     cs_gen_state(cs_state &csr):
-        cs(csr), prevps(csr.p_pstate), code(),
+        cs(csr), prevps(csr.p_pstate), code{cs},
         source(nullptr), current_line(1), src_name()
     {
         csr.p_pstate = this;
@@ -171,9 +171,7 @@ struct cs_gen_state {
         }
         code.push_back(CS_CODE_VAL | CS_RET_STRING | (word.size() << 8));
         auto it = reinterpret_cast<uint32_t const *>(word.data());
-        code.insert(
-            code.end(), it, it + (word.size() / sizeof(uint32_t))
-        );
+        code.append(it, it + (word.size() / sizeof(uint32_t)));
         size_t esz = word.size() % sizeof(uint32_t);
         union {
             char c[sizeof(uint32_t)];
@@ -202,7 +200,7 @@ struct cs_gen_state {
             } c;
             c.i = i;
             code.push_back(CS_CODE_VAL | CS_RET_INT);
-            code.insert(code.end(), c.u, c.u + CsTypeStorageSize<cs_int>);
+            code.append(c.u, c.u + CsTypeStorageSize<cs_int>);
         }
     }
 
@@ -218,7 +216,7 @@ struct cs_gen_state {
             } c;
             c.f = f;
             code.push_back(CS_CODE_VAL | CS_RET_FLOAT);
-            code.insert(code.end(), c.u, c.u + CsTypeStorageSize<cs_float>);
+            code.append(c.u, c.u + CsTypeStorageSize<cs_float>);
         }
     }
 
diff --git a/src/lib_list.cc b/src/lib_list.cc
index 4622869..7269531 100644
--- a/src/lib_list.cc
+++ b/src/lib_list.cc
@@ -543,7 +543,7 @@ static void cs_list_sort(
 
     cs_alias *xa = static_cast<cs_alias *>(x), *ya = static_cast<cs_alias *>(y);
 
-    cs_vector<ListSortItem> items;
+    cs_valbuf<ListSortItem> items{cs};
     size_t total = 0;
 
     for (cs_list_parse_state p{list}; list_parse(p, cs);) {
@@ -567,7 +567,7 @@ static void cs_list_sort(
     size_t nuniq = items.size();
     if (body) {
         ListSortFun f = { cs, xval, yval, body };
-        ostd::sort_cmp(ostd::iter(items), f);
+        ostd::sort_cmp(ostd::iter(items.buf), f);
         if (!cs_code_is_empty(unique)) {
             f.body = unique;
             totaluniq = items[0].quote.size();