Introduce Cosmopolitan Templates Library (CTL)

ctl/.clang-format

@@ -0,0 +1,12 @@
+---
+BasedOnStyle: Mozilla
+IndentWidth: 4
+ColumnLimit: 80
+---
+Language: Cpp
+AllowShortFunctionsOnASingleLine: false
+AlignTrailingComments: false
+AlignEscapedNewlines: DontAlign
+AlwaysBreakTemplateDeclarations: true
+ConstructorInitializerAllOnOneLineOrOnePerLine: true
+---

ctl/BUILD.mk

@@ -0,0 +1,48 @@
+#-*-mode:makefile-gmake;indent-tabs-mode:t;tab-width:8;coding:utf-8-*-┐
+#── vi: set noet ft=make ts=8 sw=8 fenc=utf-8 :vi ────────────────────┘
+
+PKGS += CTL
+
+CTL_ARTIFACTS += CTL_A
+CTL = $(CTL_A_DEPS) $(CTL_A)
+CTL_A = o/$(MODE)/ctl/ctl.a
+CTL_A_FILES := $(wildcard ctl/*)
+CTL_A_HDRS = $(filter %.h,$(CTL_A_FILES))
+CTL_A_SRCS = $(filter %.cc,$(CTL_A_FILES))
+CTL_A_OBJS = $(CTL_A_SRCS:%.cc=o/$(MODE)/%.o)
+
+CTL_A_CHECKS =						\
+	$(CTL_A).pkg					\
+	$(CTL_A_HDRS:%=o/$(MODE)/%.okk)			\
+
+CTL_A_DIRECTDEPS =					\
+	LIBC_INTRIN					\
+	LIBC_MEM					\
+	LIBC_STR					\
+
+CTL_A_DEPS := $(call uniq,$(foreach x,$(CTL_A_DIRECTDEPS),$($(x))))
+
+$(CTL_A):	ctl/					\
+		$(CTL_A).pkg				\
+		$(CTL_A_OBJS)
+
+$(CTL_A).pkg:						\
+		$(CTL_A_OBJS)				\
+		$(foreach x,$(CTL_A_DIRECTDEPS),$($(x)_A).pkg)
+
+$(CTL_A_OBJS): private					\
+		OVERRIDE_CXXFLAGS +=			\
+			-Wframe-larger-than=4096	\
+			-Walloca-larger-than=4096	\
+			-ffunction-sections		\
+			-fdata-sections			\
+
+CTL_LIBS = $(foreach x,$(CTL_ARTIFACTS),$($(x)))
+CTL_SRCS = $(foreach x,$(CTL_ARTIFACTS),$($(x)_SRCS))
+CTL_HDRS = $(foreach x,$(CTL_ARTIFACTS),$($(x)_HDRS))
+CTL_CHECKS = $(foreach x,$(CTL_ARTIFACTS),$($(x)_CHECKS))
+CTL_OBJS = $(foreach x,$(CTL_ARTIFACTS),$($(x)_OBJS))
+$(CTL_OBJS): $(BUILD_FILES) ctl/BUILD.mk
+
+.PHONY: o/$(MODE)/ctl
+o/$(MODE)/ctl: $(CTL_CHECKS)

ctl/optional.h

@@ -0,0 +1,125 @@
+// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
+// vi: set et ft=c++ ts=4 sts=4 sw=4 fenc=utf-8 :vi
+#ifndef COSMOPOLITAN_CTL_OPTIONAL_H_
+#define COSMOPOLITAN_CTL_OPTIONAL_H_
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <__utility/swap.h>
+
+template<typename T>
+class Optional
+{
+  public:
+    using value_type = T;
+
+    ~Optional() = default;
+
+    Optional() noexcept : present_(false)
+    {
+    }
+
+    Optional(const T& value) : present_(true), value_(value)
+    {
+    }
+
+    Optional(T&& value) : present_(true), value_(std::move(value))
+    {
+    }
+
+    Optional(const Optional& other) : present_(other.present_)
+    {
+        if (present_)
+            new (&value_) T(other.value_);
+    }
+
+    Optional(Optional&& other) noexcept : present_(other.present_)
+    {
+        if (present_)
+            value_ = std::move(other.value_);
+    }
+
+    Optional& operator=(const Optional& other)
+    {
+        if (this != &other) {
+            present_ = other.present_;
+            if (present_)
+                value_ = other.value_;
+        }
+        return *this;
+    }
+
+    Optional& operator=(Optional&& other) noexcept
+    {
+        if (this != &other) {
+            present_ = other.present_;
+            if (present_)
+                value_ = std::move(other.value_);
+        }
+        return *this;
+    }
+
+    T& value() &
+    {
+        if (!present_)
+            __builtin_trap();
+        return value_;
+    }
+
+    const T& value() const&
+    {
+        if (!present_)
+            __builtin_trap();
+        return value_;
+    }
+
+    T&& value() &&
+    {
+        if (!present_)
+            __builtin_trap();
+        return std::move(value_);
+    }
+
+    explicit operator bool() const noexcept
+    {
+        return present_;
+    }
+
+    bool has_value() const noexcept
+    {
+        return present_;
+    }
+
+    void reset() noexcept
+    {
+        if (present_) {
+            value_.~T();
+            present_ = false;
+        }
+    }
+
+    template<typename... Args>
+    void emplace(Args&&... args)
+    {
+        present_ = true;
+        value_ = T(std::forward<Args>(args)...);
+    }
+
+    void swap(Optional& other) noexcept
+    {
+        if (present_ && other.present_) {
+            std::swap(value_, other.value_);
+        } else if (present_) {
+            other.emplace(std::move(value_));
+            reset();
+        } else if (other.present_) {
+            emplace(std::move(other.value_));
+            other.reset();
+        }
+    }
+
+  private:
+    bool present_;
+    T value_;
+};
+
+#endif // COSMOPOLITAN_CTL_OPTIONAL_H_

ctl/string.cc

@@ -0,0 +1,439 @@
+// -*- mode:c++; indent-tabs-mode:nil; c-basic-offset:4; coding:utf-8 -*-
+// vi: set et ft=c++ ts=4 sts=4 sw=4 fenc=utf-8
+//
+// Copyright 2024 Justine Alexandra Roberts Tunney
+//
+// Permission to use, copy, modify, and/or distribute this software for
+// any purpose with or without fee is hereby granted, provided that the
+// above copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+// WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+// AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+// DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+// PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+// TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+#include "string.h"
+
+#include <__atomic/fence.h>
+#include <stdckdint.h>
+
+String::~String() noexcept
+{
+    if (n) {
+        if (n >= c)
+            __builtin_trap();
+        if (p[n])
+            __builtin_trap();
+    }
+    if (c && !p)
+        __builtin_trap();
+    free(p);
+}
+
+String::String(const char* s) noexcept
+{
+    append(s, strlen(s));
+}
+
+String::String(const String& s) noexcept
+{
+    append(s.p, s.n);
+}
+
+String::String(const StringView s) noexcept
+{
+    append(s.p, s.n);
+}
+
+String::String(size_t size, char ch) noexcept
+{
+    resize(size, ch);
+}
+
+String::String(const char* s, size_t size) noexcept
+{
+    append(s, size);
+}
+
+const char*
+String::c_str() const noexcept
+{
+    if (!n)
+        return "";
+    if (n >= c)
+        __builtin_trap();
+    if (p[n])
+        __builtin_trap();
+    return p;
+}
+
+void
+String::reserve(size_t c2) noexcept
+{
+    char* p2;
+    if (c2 < n)
+        c2 = n;
+    if (ckd_add(&c2, c2, 15))
+        __builtin_trap();
+    c2 &= -16;
+    if (!(p2 = (char*)realloc(p, c2)))
+        __builtin_trap();
+    std::atomic_signal_fence(std::memory_order_seq_cst);
+    c = c2;
+    p = p2;
+}
+
+void
+String::resize(size_t n2, char ch) noexcept
+{
+    size_t c2;
+    if (ckd_add(&c2, n2, 1))
+        __builtin_trap();
+    reserve(c2);
+    if (n2 > n)
+        memset(p + n, ch, n2 - n);
+    p[n = n2] = 0;
+}
+
+void
+String::append(char ch) noexcept
+{
+    if (n + 2 > c) {
+        size_t c2 = c + 2;
+        c2 += c2 >> 1;
+        reserve(c2);
+    }
+    p[n++] = ch;
+    p[n] = 0;
+}
+
+void
+String::grow(size_t size) noexcept
+{
+    size_t need;
+    if (ckd_add(&need, n, size))
+        __builtin_trap();
+    if (ckd_add(&need, need, 1))
+        __builtin_trap();
+    if (need <= c)
+        return;
+    size_t c2 = c;
+    if (!c2) {
+        c2 = need;
+    } else {
+        while (c2 < need)
+            if (ckd_add(&c2, c2, c2 >> 1))
+                __builtin_trap();
+    }
+    reserve(c2);
+}
+
+void
+String::append(char ch, size_t size) noexcept
+{
+    grow(size);
+    if (size)
+        memset(p + n, ch, size);
+    p[n += size] = 0;
+}
+
+void
+String::append(const void* data, size_t size) noexcept
+{
+    grow(size);
+    if (size)
+        memcpy(p + n, data, size);
+    p[n += size] = 0;
+}
+
+void
+String::pop_back() noexcept
+{
+    if (!n)
+        __builtin_trap();
+    p[--n] = 0;
+}
+
+String&
+String::operator=(String&& s) noexcept
+{
+    if (p != s.p) {
+        free(p);
+        p = s.p;
+        n = s.n;
+        c = s.c;
+        s.p = nullptr;
+        s.n = 0;
+        s.c = 0;
+    }
+    return *this;
+}
+
+static String
+StrCat(const StringView lhs, const StringView rhs) noexcept
+{
+    String res;
+    size_t need;
+    if (ckd_add(&need, lhs.n, rhs.n))
+        __builtin_trap();
+    if (ckd_add(&need, need, 1))
+        __builtin_trap();
+    res.reserve(need);
+    if (lhs.n)
+        memcpy(res.p, lhs.p, lhs.n);
+    if (rhs.n)
+        memcpy(res.p + lhs.n, rhs.p, rhs.n);
+    res.p[res.n = lhs.n + rhs.n] = 0;
+    return res;
+}
+
+String
+StringView::operator+(const StringView s) const noexcept
+{
+    return StrCat(*this, s);
+}
+
+String
+String::operator+(const StringView s) const noexcept
+{
+    return StrCat(*this, s);
+}
+
+bool
+String::operator==(const StringView s) const noexcept
+{
+    if (n != s.n)
+        return false;
+    return !memcmp(p, s.p, n);
+}
+
+bool
+String::operator!=(const StringView s) const noexcept
+{
+    if (n != s.n)
+        return true;
+    return !!memcmp(p, s.p, n);
+}
+
+bool
+String::contains(const StringView s) const noexcept
+{
+    if (!s.n)
+        return true;
+    return !!memmem(p, n, s.p, s.n);
+}
+
+bool
+String::ends_with(const StringView s) const noexcept
+{
+    if (n < s.n)
+        return false;
+    return !memcmp(p + n - s.n, s.p, s.n);
+}
+
+bool
+String::starts_with(const StringView s) const noexcept
+{
+    if (n < s.n)
+        return false;
+    return !memcmp(p, s.p, s.n);
+}
+
+static int
+StrCmp(const StringView lhs, const StringView rhs) noexcept
+{
+    int r;
+    size_t m = lhs.n;
+    if ((m = rhs.n < m ? rhs.n : m))
+        if ((r = memcmp(lhs.p, rhs.p, m)))
+            return r;
+    if (lhs.n == rhs.n)
+        return 0;
+    if (m < lhs.n)
+        return +1;
+    return -1;
+}
+
+int
+String::compare(const StringView s) const noexcept
+{
+    return StrCmp(*this, s);
+}
+
+size_t
+String::find(char ch, size_t pos) const noexcept
+{
+    char* q;
+    if ((q = (char*)memchr(p, ch, n)))
+        return q - p;
+    return npos;
+}
+
+size_t
+String::find(const StringView s, size_t pos) const noexcept
+{
+    char* q;
+    if (pos > n)
+        __builtin_trap();
+    if ((q = (char*)memmem(p + pos, n - pos, s.p, s.n)))
+        return q - p;
+    return npos;
+}
+
+String
+String::substr(size_t pos, size_t count) const noexcept
+{
+    size_t last;
+    if (pos > n)
+        __builtin_trap();
+    if (count > n - pos)
+        count = n - pos;
+    if (ckd_add(&last, pos, count))
+        last = n;
+    if (last > n)
+        __builtin_trap();
+    return String(p + pos, count);
+}
+
+String&
+String::replace(size_t pos, size_t count, const StringView& s) noexcept
+{
+    size_t last;
+    if (ckd_add(&last, pos, count))
+        __builtin_trap();
+    if (last > n)
+        __builtin_trap();
+    size_t need;
+    if (ckd_add(&need, pos, s.n))
+        __builtin_trap();
+    size_t extra = n - last;
+    if (ckd_add(&need, need, extra))
+        __builtin_trap();
+    size_t c2;
+    if (ckd_add(&c2, need, 1))
+        __builtin_trap();
+    reserve(c2);
+    if (extra)
+        memmove(p + pos + s.n, p + last, extra);
+    memcpy(p + pos, s.p, s.n);
+    p[n = need] = 0;
+    return *this;
+}
+
+int
+StringView::compare(const StringView s) const noexcept
+{
+    return StrCmp(*this, s);
+}
+
+size_t
+StringView::find(char ch, size_t pos) const noexcept
+{
+    char* q;
+    if (n && (q = (char*)memchr(p, ch, n)))
+        return q - p;
+    return npos;
+}
+
+size_t
+StringView::find(const StringView s, size_t pos) const noexcept
+{
+    char* q;
+    if (pos > n)
+        __builtin_trap();
+    if ((q = (char*)memmem(p + pos, n - pos, s.p, s.n)))
+        return q - p;
+    return npos;
+}
+
+StringView
+StringView::substr(size_t pos, size_t count) const noexcept
+{
+    size_t last;
+    if (pos > n)
+        __builtin_trap();
+    if (count > n - pos)
+        count = n - pos;
+    if (ckd_add(&last, pos, count))
+        last = n;
+    if (last > n)
+        __builtin_trap();
+    return StringView(p + pos, count);
+}
+
+String&
+String::insert(size_t i, const StringView s) noexcept
+{
+    if (i > n)
+        __builtin_trap();
+    size_t extra = n - i;
+    size_t need;
+    if (ckd_add(&need, n, s.n))
+        __builtin_trap();
+    if (ckd_add(&need, need, 1))
+        __builtin_trap();
+    reserve(need);
+    if (extra)
+        memmove(p + i + s.n, p + i, extra);
+    memcpy(p + i, s.p, s.n);
+    p[n += s.n] = 0;
+    return *this;
+}
+
+String&
+String::erase(size_t pos, size_t count) noexcept
+{
+    if (pos > n)
+        __builtin_trap();
+    if (count > n - pos)
+        count = n - pos;
+    size_t extra = n - (pos + count);
+    if (extra)
+        memmove(p + pos, p + pos + count, extra);
+    p[n = pos + extra] = 0;
+    return *this;
+}
+
+bool
+StringView::operator==(const StringView s) const noexcept
+{
+    if (n == s.n)
+        return true;
+    return !memcmp(p, s.p, n);
+}
+
+bool
+StringView::operator!=(const StringView s) const noexcept
+{
+    if (n != s.n)
+        return true;
+    return !!memcmp(p, s.p, n);
+}
+
+bool
+StringView::contains(const StringView s) const noexcept
+{
+    if (!s.n)
+        return true;
+    return !!memmem(p, n, s.p, s.n);
+}
+
+bool
+StringView::ends_with(const StringView s) const noexcept
+{
+    if (n < s.n)
+        return false;
+    return !memcmp(p + n - s.n, s.p, s.n);
+}
+
+bool
+StringView::starts_with(const StringView s) const noexcept
+{
+    if (n < s.n)
+        return false;
+    return !memcmp(p, s.p, s.n);
+}

ctl/string.h

@@ -0,0 +1,320 @@
+// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
+// vi: set et ft=c++ ts=4 sts=4 sw=4 fenc=utf-8 :vi
+#ifndef COSMOPOLITAN_CTL_STRING_H_
+#define COSMOPOLITAN_CTL_STRING_H_
+
+struct String;
+
+struct StringView
+{
+    const char* p;
+    size_t n;
+
+    static constexpr size_t npos = -1;
+
+    constexpr StringView(const char* s) noexcept
+      : p(s), n(s ? __builtin_strlen(s) : 0)
+    {
+    }
+
+    constexpr StringView(const char* s, size_t n) noexcept : p(s), n(n)
+    {
+    }
+
+    inline constexpr ~StringView() noexcept
+    {
+    }
+
+    int compare(const StringView) const noexcept;
+    bool operator==(const StringView) const noexcept;
+    bool operator!=(const StringView) const noexcept;
+    bool contains(const StringView) const noexcept;
+    String operator+(const StringView) const noexcept;
+    bool ends_with(const StringView) const noexcept;
+    bool starts_with(const StringView) const noexcept;
+    StringView substr(size_t = 0, size_t = npos) const noexcept;
+    size_t find(char, size_t = 0) const noexcept;
+    size_t find(const StringView, size_t = 0) const noexcept;
+
+    constexpr StringView& operator=(const StringView& s) noexcept
+    {
+        p = s.p;
+        n = s.n;
+        return *this;
+    }
+
+    constexpr bool empty() const noexcept
+    {
+        return !n;
+    }
+
+    constexpr const char* data() const noexcept
+    {
+        return p;
+    }
+
+    constexpr size_t size() const noexcept
+    {
+        return n;
+    }
+
+    constexpr size_t length() const noexcept
+    {
+        return n;
+    }
+
+    constexpr const char& operator[](size_t i) const noexcept
+    {
+        if (i >= n)
+            __builtin_trap();
+        return p[i];
+    }
+
+    constexpr void remove_prefix(size_t count)
+    {
+        if (count > n)
+            __builtin_trap();
+        p += count;
+        n -= count;
+    }
+
+    constexpr void remove_suffix(size_t count)
+    {
+        if (count > n)
+            __builtin_trap();
+        n -= count;
+    }
+
+    bool operator<(const StringView& s) const noexcept
+    {
+        return compare(s) < 0;
+    }
+
+    bool operator<=(const StringView& s) const noexcept
+    {
+        return compare(s) <= 0;
+    }
+
+    bool operator>(const StringView& s) const noexcept
+    {
+        return compare(s) > 0;
+    }
+
+    bool operator>=(const StringView& s) const noexcept
+    {
+        return compare(s) >= 0;
+    }
+};
+
+struct String
+{
+    char* p = nullptr;
+    size_t n = 0;
+    size_t c = 0;
+
+    using iterator = char*;
+    using const_iterator = const char*;
+    static constexpr size_t npos = -1;
+
+    ~String() noexcept;
+    String() = default;
+    String(const StringView) noexcept;
+    String(const char*) noexcept;
+    String(const String&) noexcept;
+    String(const char*, size_t) noexcept;
+    explicit String(size_t, char = 0) noexcept;
+    String& operator=(String&&) noexcept;
+    const char* c_str() const noexcept;
+
+    void pop_back() noexcept;
+    void grow(size_t) noexcept;
+    void reserve(size_t) noexcept;
+    void resize(size_t, char = 0) noexcept;
+    void append(char) noexcept;
+    void append(char, size_t) noexcept;
+    void append(unsigned long) noexcept;
+    void append(const void*, size_t) noexcept;
+    String& insert(size_t, const StringView) noexcept;
+    String& erase(size_t = 0, size_t = npos) noexcept;
+    String operator+(const StringView) const noexcept;
+    String substr(size_t = 0, size_t = npos) const noexcept;
+    String& replace(size_t, size_t, const StringView&) noexcept;
+    bool operator==(const StringView) const noexcept;
+    bool operator!=(const StringView) const noexcept;
+    bool contains(const StringView) const noexcept;
+    bool ends_with(const StringView) const noexcept;
+    bool starts_with(const StringView) const noexcept;
+    int compare(const StringView) const noexcept;
+    size_t find(char, size_t = 0) const noexcept;
+    size_t find(const StringView, size_t = 0) const noexcept;
+
+    String(String&& s) noexcept : p(s.p), n(s.n), c(s.c)
+    {
+        s.p = nullptr;
+        s.n = 0;
+        s.c = 0;
+    }
+
+    void clear() noexcept
+    {
+        n = 0;
+    }
+
+    bool empty() const noexcept
+    {
+        return !n;
+    }
+
+    char* data() const noexcept
+    {
+        return p;
+    }
+
+    size_t size() const noexcept
+    {
+        return n;
+    }
+
+    size_t length() const noexcept
+    {
+        return n;
+    }
+
+    size_t capacity() const noexcept
+    {
+        return c;
+    }
+
+    iterator begin() noexcept
+    {
+        return p;
+    }
+
+    iterator end() noexcept
+    {
+        return p + n;
+    }
+
+    const_iterator cbegin() const noexcept
+    {
+        return p;
+    }
+
+    const_iterator cend() const noexcept
+    {
+        return p + n;
+    }
+
+    char& front()
+    {
+        if (!n)
+            __builtin_trap();
+        return p[0];
+    }
+
+    const char& front() const
+    {
+        if (!n)
+            __builtin_trap();
+        return p[0];
+    }
+
+    char& back()
+    {
+        if (!n)
+            __builtin_trap();
+        return p[n - 1];
+    }
+
+    const char& back() const
+    {
+        if (!n)
+            __builtin_trap();
+        return p[n - 1];
+    }
+
+    char& operator[](size_t i) noexcept
+    {
+        if (i >= n)
+            __builtin_trap();
+        return p[i];
+    }
+
+    const char& operator[](size_t i) const noexcept
+    {
+        if (i >= n)
+            __builtin_trap();
+        return p[i];
+    }
+
+    void push_back(char ch) noexcept
+    {
+        append(ch);
+    }
+
+    void append(const StringView s) noexcept
+    {
+        append(s.p, s.n);
+    }
+
+    inline constexpr operator StringView() const noexcept
+    {
+        return StringView(p, n);
+    }
+
+    String& operator=(const char* s) noexcept
+    {
+        clear();
+        append(s);
+        return *this;
+    }
+
+    String& operator=(const StringView s) noexcept
+    {
+        clear();
+        append(s);
+        return *this;
+    }
+
+    String& operator+=(char x) noexcept
+    {
+        append(x);
+        return *this;
+    }
+
+    String& operator+=(const StringView s) noexcept
+    {
+        append(s);
+        return *this;
+    }
+
+    bool operator<(const StringView s) const noexcept
+    {
+        return compare(s) < 0;
+    }
+
+    bool operator<=(const StringView s) const noexcept
+    {
+        return compare(s) <= 0;
+    }
+
+    bool operator>(const StringView s) const noexcept
+    {
+        return compare(s) > 0;
+    }
+
+    bool operator>=(const StringView s) const noexcept
+    {
+        return compare(s) >= 0;
+    }
+};
+
+#pragma GCC diagnostic ignored "-Wliteral-suffix"
+
+inline String
+operator"" s(const char* s, size_t n)
+{
+    return String(s, n);
+}
+
+#endif // COSMOPOLITAN_CTL_STRING_H_

ctl/vector.h

@@ -0,0 +1,242 @@
+// -*-mode:c++;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8-*-
+// vi: set et ft=c++ ts=4 sts=4 sw=4 fenc=utf-8 :vi
+#ifndef COSMOPOLITAN_CTL_OPTIONAL_H_
+#define COSMOPOLITAN_CTL_OPTIONAL_H_
+#include <__utility/forward.h>
+#include <__utility/move.h>
+#include <__utility/swap.h>
+
+template<typename T>
+struct Vector
+{
+    size_t n = 0;
+    size_t c = 0;
+    T* p = nullptr;
+
+    using iterator = T*;
+    using const_iterator = const T*;
+
+    Vector() = default;
+
+    ~Vector()
+    {
+        delete[] p;
+    }
+
+    Vector(const Vector& other)
+    {
+        n = other.n;
+        c = other.c;
+        p = new T[c];
+        for (size_t i = 0; i < n; ++i)
+            new (&p[i]) T(other.p[i]);
+    }
+
+    Vector(Vector&& other) noexcept
+    {
+        n = other.n;
+        c = other.c;
+        p = other.p;
+        other.n = 0;
+        other.c = 0;
+        other.p = nullptr;
+    }
+
+    explicit Vector(size_t count, const T& value = T())
+    {
+        n = count;
+        c = count;
+        p = new T[c];
+        for (size_t i = 0; i < n; ++i)
+            new (&p[i]) T(value);
+    }
+
+    Vector& operator=(const Vector& other)
+    {
+        if (this != &other) {
+            T* newData = new T[other.c];
+            for (size_t i = 0; i < other.n; ++i) {
+                newData[i] = other.p[i];
+            }
+            delete[] p;
+            p = newData;
+            n = other.n;
+            c = other.c;
+        }
+        return *this;
+    }
+
+    Vector& operator=(Vector&& other) noexcept
+    {
+        if (this != &other) {
+            delete[] p;
+            p = other.p;
+            n = other.n;
+            c = other.c;
+            other.p = nullptr;
+            other.n = 0;
+            other.c = 0;
+        }
+        return *this;
+    }
+
+    bool empty() const
+    {
+        return !n;
+    }
+
+    size_t size() const
+    {
+        return n;
+    }
+
+    size_t capacity() const
+    {
+        return c;
+    }
+
+    T& operator[](size_t i)
+    {
+        if (i >= n)
+            __builtin_trap();
+        return p[i];
+    }
+
+    const T& operator[](size_t i) const
+    {
+        if (i >= n)
+            __builtin_trap();
+        return p[i];
+    }
+
+    iterator begin()
+    {
+        return p;
+    }
+
+    iterator end()
+    {
+        return p + n;
+    }
+
+    const_iterator cbegin() const
+    {
+        return p;
+    }
+
+    const_iterator cend() const
+    {
+        return p + n;
+    }
+
+    T& front()
+    {
+        if (!n)
+            __builtin_trap();
+        return p[0];
+    }
+
+    const T& front() const
+    {
+        if (!n)
+            __builtin_trap();
+        return p[0];
+    }
+
+    T& back()
+    {
+        if (!n)
+            __builtin_trap();
+        return p[n - 1];
+    }
+
+    const T& back() const
+    {
+        if (!n)
+            __builtin_trap();
+        return p[n - 1];
+    }
+
+    void clear()
+    {
+        for (size_t i = 0; i < n; ++i)
+            p[i].~T();
+        n = 0;
+    }
+
+    void reserve(size_t c2)
+    {
+        if (c2 <= c)
+            return;
+        T* newP = new T[c2];
+        for (size_t i = 0; i < n; ++i)
+            newP[i] = std::move(p[i]);
+        delete[] p;
+        p = newP;
+        c = c2;
+    }
+
+    void push_back(const T& e)
+    {
+        if (n == c) {
+            size_t c2 = c + 1;
+            c2 += c2 >> 1;
+            reserve(c2);
+        }
+        new (&p[n]) T(e);
+        ++n;
+    }
+
+    void push_back(T&& e)
+    {
+        if (n == c) {
+            size_t c2 = c + 1;
+            c2 += c2 >> 1;
+            reserve(c2);
+        }
+        new (&p[n]) T(std::forward<T>(e));
+        ++n;
+    }
+
+    template<typename... Args>
+    void emplace_back(Args&&... args)
+    {
+        if (n == c) {
+            size_t c2 = c + 1;
+            c2 += c2 >> 1;
+            reserve(c2);
+        }
+        new (&p[n]) T(std::forward<Args>(args)...);
+        ++n;
+    }
+
+    void pop_back()
+    {
+        if (n > 0) {
+            --n;
+            p[n].~T();
+        }
+    }
+
+    void resize(size_t n2)
+    {
+        if (n2 > n) {
+            reserve(n2);
+            for (size_t i = n; i < n2; ++i)
+                new (&p[i]) T();
+        } else if (n2 < n) {
+            for (size_t i = n2; i < n; ++i)
+                p[i].~T();
+        }
+        n = n2;
+    }
+
+    void swap(Vector& other) noexcept
+    {
+        std::swap(n, other.n);
+        std::swap(c, other.c);
+        std::swap(p, other.p);
+    }
+};
+
+#endif // COSMOPOLITAN_CTL_OPTIONAL_H_