--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/include/kj/string.h	Tue Mar 18 17:55:14 2025 -0400
@@ -0,0 +1,935 @@
+// Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
+// Licensed under the MIT License:
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#pragma once
+
+#include <initializer_list>
+#include "array.h"
+#include "kj/common.h"
+#include <string.h>
+
+KJ_BEGIN_HEADER
+
+namespace kj {
+  class StringPtr;
+  class LiteralStringConst;
+  class String;
+  class ConstString;
+
+  class StringTree;   // string-tree.h
+}
+
+constexpr kj::StringPtr operator "" _kj(const char* str, size_t n);
+// You can append _kj to a string literal to make its type be StringPtr. There are a few cases
+// where you must do this for correctness:
+// - When you want to declare a constexpr StringPtr. Without _kj, this is a compile error.
+// - When you want to initialize a static/global StringPtr from a string literal without forcing
+//   global constructor code to run at dynamic initialization time.
+// - When you have a string literal that contains NUL characters. Without _kj, the string will
+//   be considered to end at the first NUL.
+// - When you want to initialize an ArrayPtr<const char> from a string literal, without including
+//   the NUL terminator in the data. (Initializing an ArrayPtr from a regular string literal is
+//   a compile error specifically due to this ambiguity.)
+//
+// In other cases, there should be no difference between initializing a StringPtr from a regular
+// string literal vs. one with _kj (assuming the compiler is able to optimize away strlen() on a
+// string literal).
+
+constexpr kj::LiteralStringConst operator "" _kjc(const char* str, size_t n);
+
+namespace kj {
+
+// Our STL string SFINAE trick does not work with GCC 4.7, but it works with Clang and GCC 4.8, so
+// we'll just preprocess it out if not supported.
+#if __clang__ || __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8) || _MSC_VER
+#define KJ_COMPILER_SUPPORTS_STL_STRING_INTEROP 1
+#endif
+
+// =======================================================================================
+// StringPtr -- A NUL-terminated ArrayPtr<const char> containing UTF-8 text.
+//
+// NUL bytes are allowed to appear before the end of the string.  The only requirement is that
+// a NUL byte appear immediately after the last byte of the content.  This terminator byte is not
+// counted in the string's size.
+
+class StringPtr {
+public:
+  inline StringPtr(): content("", 1) {}
+  inline StringPtr(decltype(nullptr)): content("", 1) {}
+  inline StringPtr(const char* value KJ_LIFETIMEBOUND): content(value, strlen(value) + 1) {}
+  inline StringPtr(const char* value KJ_LIFETIMEBOUND, size_t size): content(value, size + 1) {
+    KJ_IREQUIRE(value[size] == '\0', "StringPtr must be NUL-terminated.");
+  }
+  inline StringPtr(const char* begin KJ_LIFETIMEBOUND, const char* end KJ_LIFETIMEBOUND): StringPtr(begin, end - begin) {}
+  inline StringPtr(String&& value KJ_LIFETIMEBOUND) : StringPtr(value) {}
+  inline StringPtr(const String& value KJ_LIFETIMEBOUND);
+  inline StringPtr(const ConstString& value KJ_LIFETIMEBOUND);
+  StringPtr& operator=(String&& value) = delete;
+  inline StringPtr& operator=(decltype(nullptr)) {
+    content = ArrayPtr<const char>("", 1);
+    return *this;
+  }
+
+#if __cpp_char8_t
+  inline StringPtr(const char8_t* value KJ_LIFETIMEBOUND): StringPtr(reinterpret_cast<const char*>(value)) {}
+  inline StringPtr(const char8_t* value KJ_LIFETIMEBOUND, size_t size)
+      : StringPtr(reinterpret_cast<const char*>(value), size) {}
+  inline StringPtr(const char8_t* begin KJ_LIFETIMEBOUND, const char8_t* end KJ_LIFETIMEBOUND)
+      : StringPtr(reinterpret_cast<const char*>(begin), reinterpret_cast<const char*>(end)) {}
+  // KJ strings are and always have been UTF-8, so screw this C++20 char8_t stuff.
+#endif
+
+#if KJ_COMPILER_SUPPORTS_STL_STRING_INTEROP
+  template <
+    typename T,
+    typename = decltype(instance<T>().c_str()),
+    typename = decltype(instance<T>().size())>
+  inline StringPtr(const T& t KJ_LIFETIMEBOUND): StringPtr(t.c_str(), t.size()) {}
+  // Allow implicit conversion from any class that has a c_str() and a size() method (namely, std::string).
+  // We use a template trick to detect std::string in order to avoid including the header for
+  // those who don't want it.
+  template <
+    typename T,
+    typename = decltype(instance<T>().c_str()),
+    typename = decltype(instance<T>().size())>
+  inline operator T() const { return {cStr(), size()}; }
+  // Allow implicit conversion to any class that has a c_str() method and a size() method (namely, std::string).
+  // We use a template trick to detect std::string in order to avoid including the header for
+  // those who don't want it.
+#endif
+
+  inline constexpr operator ArrayPtr<const char>() const;
+  inline constexpr ArrayPtr<const char> asArray() const;
+  inline ArrayPtr<const byte> asBytes() const { return asArray().asBytes(); }
+  // Result does not include NUL terminator.
+
+  inline const char* cStr() const { return content.begin(); }
+  // Returns NUL-terminated string.
+
+  inline size_t size() const { return content.size() - 1; }
+  // Result does not include NUL terminator.
+
+  inline char operator[](size_t index) const { return content[index]; }
+
+  inline constexpr const char* begin() const { return content.begin(); }
+  inline constexpr const char* end() const { return content.end() - 1; }
+
+  inline constexpr bool operator==(decltype(nullptr)) const { return content.size() <= 1; }
+#if !__cpp_impl_three_way_comparison
+  inline constexpr bool operator!=(decltype(nullptr)) const { return content.size() > 1; }
+#endif
+
+  inline bool operator==(const StringPtr& other) const;
+#if !__cpp_impl_three_way_comparison
+  inline bool operator!=(const StringPtr& other) const { return !(*this == other); }
+#endif
+  inline bool operator< (const StringPtr& other) const;
+  inline bool operator> (const StringPtr& other) const { return other < *this; }
+  inline bool operator<=(const StringPtr& other) const { return !(other < *this); }
+  inline bool operator>=(const StringPtr& other) const { return !(*this < other); }
+
+  inline StringPtr slice(size_t start) const;
+  inline ArrayPtr<const char> slice(size_t start, size_t end) const;
+  // A string slice is only NUL-terminated if it is a suffix, so slice() has a one-parameter
+  // version that assumes end = size().
+
+  inline bool startsWith(const StringPtr& other) const { return asArray().startsWith(other);}
+  inline bool endsWith(const StringPtr& other) const { return asArray().endsWith(other); }
+
+  inline Maybe<size_t> findFirst(char c) const { return asArray().findFirst(c); }
+  inline Maybe<size_t> findLast(char c) const { return asArray().findLast(c); }
+
+  template <typename T>
+  T parseAs() const;
+  // Parse string as template number type.
+  // Integer numbers prefixed by "0x" and "0X" are parsed in base 16 (like strtoi with base 0).
+  // Integer numbers prefixed by "0" are parsed in base 10 (unlike strtoi with base 0).
+  // Overflowed integer numbers throw exception.
+  // Overflowed floating numbers return inf.
+  template <typename T>
+  Maybe<T> tryParseAs() const;
+  // Same as parseAs, but rather than throwing an exception we return NULL.
+
+  template <typename... Attachments>
+  ConstString attach(Attachments&&... attachments) const KJ_WARN_UNUSED_RESULT;
+  ConstString attach() const KJ_WARN_UNUSED_RESULT;
+  // Like ArrayPtr<T>::attach(), but instead promotes a StringPtr into a ConstString. Generally the
+  // attachment should be an object that somehow owns the String that the StringPtr is pointing at.
+
+private:
+  inline explicit constexpr StringPtr(ArrayPtr<const char> content): content(content) {}
+  friend constexpr StringPtr (::operator "" _kj)(const char* str, size_t n);
+  friend class LiteralStringConst;
+
+  ArrayPtr<const char> content;
+  friend class SourceLocation;
+};
+
+#if !__cpp_impl_three_way_comparison
+inline bool operator==(const char* a, const StringPtr& b) { return b == a; }
+inline bool operator!=(const char* a, const StringPtr& b) { return b != a; }
+#endif
+
+template <> char StringPtr::parseAs<char>() const;
+template <> signed char StringPtr::parseAs<signed char>() const;
+template <> unsigned char StringPtr::parseAs<unsigned char>() const;
+template <> short StringPtr::parseAs<short>() const;
+template <> unsigned short StringPtr::parseAs<unsigned short>() const;
+template <> int StringPtr::parseAs<int>() const;
+template <> unsigned StringPtr::parseAs<unsigned>() const;
+template <> long StringPtr::parseAs<long>() const;
+template <> unsigned long StringPtr::parseAs<unsigned long>() const;
+template <> long long StringPtr::parseAs<long long>() const;
+template <> unsigned long long StringPtr::parseAs<unsigned long long>() const;
+template <> float StringPtr::parseAs<float>() const;
+template <> double StringPtr::parseAs<double>() const;
+
+template <> Maybe<char> StringPtr::tryParseAs<char>() const;
+template <> Maybe<signed char> StringPtr::tryParseAs<signed char>() const;
+template <> Maybe<unsigned char> StringPtr::tryParseAs<unsigned char>() const;
+template <> Maybe<short> StringPtr::tryParseAs<short>() const;
+template <> Maybe<unsigned short> StringPtr::tryParseAs<unsigned short>() const;
+template <> Maybe<int> StringPtr::tryParseAs<int>() const;
+template <> Maybe<unsigned> StringPtr::tryParseAs<unsigned>() const;
+template <> Maybe<long> StringPtr::tryParseAs<long>() const;
+template <> Maybe<unsigned long> StringPtr::tryParseAs<unsigned long>() const;
+template <> Maybe<long long> StringPtr::tryParseAs<long long>() const;
+template <> Maybe<unsigned long long> StringPtr::tryParseAs<unsigned long long>() const;
+template <> Maybe<float> StringPtr::tryParseAs<float>() const;
+template <> Maybe<double> StringPtr::tryParseAs<double>() const;
+
+class LiteralStringConst: public StringPtr {
+public:
+  inline operator ConstString() const;
+
+private:
+  inline explicit constexpr LiteralStringConst(ArrayPtr<const char> content): StringPtr(content) {}
+  friend constexpr LiteralStringConst (::operator "" _kjc)(const char* str, size_t n);
+};
+
+// =======================================================================================
+// String -- A NUL-terminated Array<char> containing UTF-8 text.
+//
+// NUL bytes are allowed to appear before the end of the string.  The only requirement is that
+// a NUL byte appear immediately after the last byte of the content.  This terminator byte is not
+// counted in the string's size.
+//
+// To allocate a String, you must call kj::heapString().  We do not implement implicit copying to
+// the heap because this hides potential inefficiency from the developer.
+
+class String {
+public:
+  String() = default;
+  inline String(decltype(nullptr)): content(nullptr) {}
+  inline String(char* value, size_t size, const ArrayDisposer& disposer);
+  // Does not copy.  `size` does not include NUL terminator, but `value` must be NUL-terminated.
+  inline explicit String(Array<char> buffer);
+  // Does not copy.  Requires `buffer` ends with `\0`.
+
+  inline operator ArrayPtr<char>() KJ_LIFETIMEBOUND;
+  inline operator ArrayPtr<const char>() const KJ_LIFETIMEBOUND;
+  inline ArrayPtr<char> asArray() KJ_LIFETIMEBOUND;
+  inline ArrayPtr<const char> asArray() const KJ_LIFETIMEBOUND;
+  inline ArrayPtr<byte> asBytes() KJ_LIFETIMEBOUND { return asArray().asBytes(); }
+  inline ArrayPtr<const byte> asBytes() const KJ_LIFETIMEBOUND { return asArray().asBytes(); }
+  // Result does not include NUL terminator.
+
+  inline StringPtr asPtr() const KJ_LIFETIMEBOUND {
+    // Convenience operator to return a StringPtr.
+    return StringPtr{*this};
+  }
+
+  inline Array<char> releaseArray() { return kj::mv(content); }
+  // Disowns the backing array (which includes the NUL terminator) and returns it. The String value
+  // is clobbered (as if moved away).
+
+  inline const char* cStr() const KJ_LIFETIMEBOUND;
+
+  inline size_t size() const;
+  // Result does not include NUL terminator.
+
+  inline char operator[](size_t index) const;
+  inline char& operator[](size_t index) KJ_LIFETIMEBOUND;
+
+  inline char* begin() KJ_LIFETIMEBOUND;
+  inline char* end() KJ_LIFETIMEBOUND;
+  inline const char* begin() const KJ_LIFETIMEBOUND;
+  inline const char* end() const KJ_LIFETIMEBOUND;
+
+  inline bool operator==(decltype(nullptr)) const { return content.size() <= 1; }
+  inline bool operator!=(decltype(nullptr)) const { return content.size() > 1; }
+
+  inline bool operator==(const StringPtr& other) const { return StringPtr(*this) == other; }
+#if !__cpp_impl_three_way_comparison
+  inline bool operator!=(const StringPtr& other) const { return StringPtr(*this) != other; }
+#endif
+  inline bool operator< (const StringPtr& other) const { return StringPtr(*this) <  other; }
+  inline bool operator> (const StringPtr& other) const { return StringPtr(*this) >  other; }
+  inline bool operator<=(const StringPtr& other) const { return StringPtr(*this) <= other; }
+  inline bool operator>=(const StringPtr& other) const { return StringPtr(*this) >= other; }
+
+  inline bool operator==(const String& other) const { return StringPtr(*this) == StringPtr(other); }
+#if !__cpp_impl_three_way_comparison
+  inline bool operator!=(const String& other) const { return StringPtr(*this) != StringPtr(other); }
+#endif
+  inline bool operator< (const String& other) const { return StringPtr(*this) <  StringPtr(other); }
+  inline bool operator> (const String& other) const { return StringPtr(*this) >  StringPtr(other); }
+  inline bool operator<=(const String& other) const { return StringPtr(*this) <= StringPtr(other); }
+  inline bool operator>=(const String& other) const { return StringPtr(*this) >= StringPtr(other); }
+  // Note that if we don't overload for `const String&` specifically, then C++20 will decide that
+  // comparisons between two strings are ambiguous. (Clang turns this into a warning,
+  // -Wambiguous-reversed-operator, due to the stupidity...)
+
+  inline bool operator==(const ConstString& other) const { return StringPtr(*this) == StringPtr(other); }
+#if !__cpp_impl_three_way_comparison
+  inline bool operator!=(const ConstString& other) const { return StringPtr(*this) != StringPtr(other); }
+#endif
+  inline bool operator< (const ConstString& other) const { return StringPtr(*this) <  StringPtr(other); }
+  inline bool operator> (const ConstString& other) const { return StringPtr(*this) >  StringPtr(other); }
+  inline bool operator<=(const ConstString& other) const { return StringPtr(*this) <= StringPtr(other); }
+  inline bool operator>=(const ConstString& other) const { return StringPtr(*this) >= StringPtr(other); }
+
+  inline bool startsWith(const StringPtr& other) const { return asArray().startsWith(other);}
+  inline bool endsWith(const StringPtr& other) const { return asArray().endsWith(other); }
+
+  inline StringPtr slice(size_t start) const KJ_LIFETIMEBOUND {
+    return StringPtr(*this).slice(start);
+  }
+  inline ArrayPtr<const char> slice(size_t start, size_t end) const KJ_LIFETIMEBOUND {
+    return StringPtr(*this).slice(start, end);
+  }
+
+  inline Maybe<size_t> findFirst(char c) const { return asArray().findFirst(c); }
+  inline Maybe<size_t> findLast(char c) const { return asArray().findLast(c); }
+
+  template <typename T>
+  T parseAs() const { return StringPtr(*this).parseAs<T>(); }
+  // Parse as number
+
+  template <typename T>
+  Maybe<T> tryParseAs() const { return StringPtr(*this).tryParseAs<T>(); }
+
+private:
+  Array<char> content;
+};
+
+// =======================================================================================
+// ConstString -- Same as String, but the backing buffer is const.
+//
+// This has the useful property that it can reference a string literal without allocating
+// a copy. Any String can also convert (by move) to ConstString, transferring ownership of
+// the buffer.
+
+class ConstString {
+public:
+  ConstString() = default;
+  inline ConstString(decltype(nullptr)): content(nullptr) {}
+  inline ConstString(const char* value, size_t size, const ArrayDisposer& disposer);
+  // Does not copy.  `size` does not include NUL terminator, but `value` must be NUL-terminated.
+  inline explicit ConstString(Array<const char> buffer);
+  // Does not copy.  Requires `buffer` ends with `\0`.
+  inline explicit ConstString(String&& string): content(string.releaseArray()) {}
+  // Does not copy. Ownership is transfered.
+
+  inline operator ArrayPtr<const char>() const KJ_LIFETIMEBOUND;
+  inline ArrayPtr<const char> asArray() const KJ_LIFETIMEBOUND;
+  inline ArrayPtr<const byte> asBytes() const KJ_LIFETIMEBOUND { return asArray().asBytes(); }
+  // Result does not include NUL terminator.
+
+  inline StringPtr asPtr() const KJ_LIFETIMEBOUND {
+    // Convenience operator to return a StringPtr.
+    return StringPtr{*this};
+  }
+
+  inline Array<const char> releaseArray() { return kj::mv(content); }
+  // Disowns the backing array (which includes the NUL terminator) and returns it. The ConstString value
+  // is clobbered (as if moved away).
+
+  inline const char* cStr() const KJ_LIFETIMEBOUND;
+
+  inline size_t size() const;
+  // Result does not include NUL terminator.
+
+  inline char operator[](size_t index) const;
+  inline char& operator[](size_t index) KJ_LIFETIMEBOUND;
+
+  inline const char* begin() const KJ_LIFETIMEBOUND;
+  inline const char* end() const KJ_LIFETIMEBOUND;
+
+  inline bool operator==(decltype(nullptr)) const { return content.size() <= 1; }
+  inline bool operator!=(decltype(nullptr)) const { return content.size() > 1; }
+
+  inline bool operator==(const StringPtr& other) const { return StringPtr(*this) == other; }
+#if !__cpp_impl_three_way_comparison
+  inline bool operator!=(const StringPtr& other) const { return StringPtr(*this) != other; }
+#endif
+  inline bool operator< (const StringPtr& other) const { return StringPtr(*this) <  other; }
+  inline bool operator> (const StringPtr& other) const { return StringPtr(*this) >  other; }
+  inline bool operator<=(const StringPtr& other) const { return StringPtr(*this) <= other; }
+  inline bool operator>=(const StringPtr& other) const { return StringPtr(*this) >= other; }
+
+  inline bool operator==(const String& other) const { return StringPtr(*this) == StringPtr(other); }
+#if !__cpp_impl_three_way_comparison
+  inline bool operator!=(const String& other) const { return StringPtr(*this) != StringPtr(other); }
+#endif
+  inline bool operator< (const String& other) const { return StringPtr(*this) <  StringPtr(other); }
+  inline bool operator> (const String& other) const { return StringPtr(*this) >  StringPtr(other); }
+  inline bool operator<=(const String& other) const { return StringPtr(*this) <= StringPtr(other); }
+  inline bool operator>=(const String& other) const { return StringPtr(*this) >= StringPtr(other); }
+
+  inline bool operator==(const ConstString& other) const { return StringPtr(*this) == StringPtr(other); }
+#if !__cpp_impl_three_way_comparison
+  inline bool operator!=(const ConstString& other) const { return StringPtr(*this) != StringPtr(other); }
+#endif
+  inline bool operator< (const ConstString& other) const { return StringPtr(*this) <  StringPtr(other); }
+  inline bool operator> (const ConstString& other) const { return StringPtr(*this) >  StringPtr(other); }
+  inline bool operator<=(const ConstString& other) const { return StringPtr(*this) <= StringPtr(other); }
+  inline bool operator>=(const ConstString& other) const { return StringPtr(*this) >= StringPtr(other); }
+  // Note that if we don't overload for `const ConstString&` specifically, then C++20 will decide that
+  // comparisons between two strings are ambiguous. (Clang turns this into a warning,
+  // -Wambiguous-reversed-operator, due to the stupidity...)
+
+  inline bool startsWith(const StringPtr& other) const { return asArray().startsWith(other);}
+  inline bool endsWith(const StringPtr& other) const { return asArray().endsWith(other); }
+
+  inline StringPtr slice(size_t start) const KJ_LIFETIMEBOUND {
+    return StringPtr(*this).slice(start);
+  }
+  inline ArrayPtr<const char> slice(size_t start, size_t end) const KJ_LIFETIMEBOUND {
+    return StringPtr(*this).slice(start, end);
+  }
+
+  inline Maybe<size_t> findFirst(char c) const { return asArray().findFirst(c); }
+  inline Maybe<size_t> findLast(char c) const { return asArray().findLast(c); }
+
+  template <typename T>
+  T parseAs() const { return StringPtr(*this).parseAs<T>(); }
+  // Parse as number
+
+  template <typename T>
+  Maybe<T> tryParseAs() const { return StringPtr(*this).tryParseAs<T>(); }
+
+private:
+  Array<const char> content;
+};
+
+#if !__cpp_impl_three_way_comparison
+inline bool operator==(const char* a, const String& b) { return b == a; }
+inline bool operator!=(const char* a, const String& b) { return b != a; }
+#endif
+
+String heapString(size_t size);
+// Allocate a String of the given size on the heap, not including NUL terminator.  The NUL
+// terminator will be initialized automatically but the rest of the content is not initialized.
+
+String heapString(const char* value);
+String heapString(const char* value, size_t size);
+String heapString(StringPtr value);
+String heapString(const String& value);
+String heapString(ArrayPtr<const char> value);
+// Allocates a copy of the given value on the heap.
+
+// =======================================================================================
+// Magic str() function which transforms parameters to text and concatenates them into one big
+// String.
+
+namespace _ {  // private
+
+inline size_t sum(std::initializer_list<size_t> nums) {
+  size_t result = 0;
+  for (auto num: nums) {
+    result += num;
+  }
+  return result;
+}
+
+inline char* fill(char* ptr) { return ptr; }
+inline char* fillLimited(char* ptr, char* limit) { return ptr; }
+
+template <typename... Rest>
+char* fill(char* __restrict__ target, const StringTree& first, Rest&&... rest);
+template <typename... Rest>
+char* fillLimited(char* __restrict__ target, char* limit, const StringTree& first, Rest&&... rest);
+// Make str() work with stringifiers that return StringTree by patching fill().
+//
+// Defined in string-tree.h.
+
+template <typename First, typename... Rest>
+char* fill(char* __restrict__ target, const First& first, Rest&&... rest) {
+  auto i = first.begin();
+  auto end = first.end();
+  while (i != end) {
+    *target++ = *i++;
+  }
+  return fill(target, kj::fwd<Rest>(rest)...);
+}
+
+template <typename... Params>
+String concat(Params&&... params) {
+  // Concatenate a bunch of containers into a single Array.  The containers can be anything that
+  // is iterable and whose elements can be converted to `char`.
+
+  String result = heapString(sum({params.size()...}));
+  fill(result.begin(), kj::fwd<Params>(params)...);
+  return result;
+}
+
+inline String concat(String&& arr) {
+  return kj::mv(arr);
+}
+
+template <typename First, typename... Rest>
+char* fillLimited(char* __restrict__ target, char* limit, const First& first, Rest&&... rest) {
+  auto i = first.begin();
+  auto end = first.end();
+  while (i != end) {
+    if (target == limit) return target;
+    *target++ = *i++;
+  }
+  return fillLimited(target, limit, kj::fwd<Rest>(rest)...);
+}
+
+template <typename T>
+class Delimited;
+// Delimits a sequence of type T with a string delimiter. Implements kj::delimited().
+
+template <typename T, typename... Rest>
+char* fill(char* __restrict__ target, Delimited<T>&& first, Rest&&... rest);
+template <typename T, typename... Rest>
+char* fillLimited(char* __restrict__ target, char* limit, Delimited<T>&& first,Rest&&... rest);
+template <typename T, typename... Rest>
+char* fill(char* __restrict__ target, Delimited<T>& first, Rest&&... rest);
+template <typename T, typename... Rest>
+char* fillLimited(char* __restrict__ target, char* limit, Delimited<T>& first,Rest&&... rest);
+// As with StringTree, we special-case Delimited<T>.
+
+struct Stringifier {
+  // This is a dummy type with only one instance: STR (below).  To make an arbitrary type
+  // stringifiable, define `operator*(Stringifier, T)` to return an iterable container of `char`.
+  // The container type must have a `size()` method.  Be sure to declare the operator in the same
+  // namespace as `T` **or** in the global scope.
+  //
+  // A more usual way to accomplish what we're doing here would be to require that you define
+  // a function like `toString(T)` and then rely on argument-dependent lookup.  However, this has
+  // the problem that it pollutes other people's namespaces and even the global namespace.  For
+  // example, some other project may already have functions called `toString` which do something
+  // different.  Declaring `operator*` with `Stringifier` as the left operand cannot conflict with
+  // anything.
+
+  inline ArrayPtr<const char> operator*(ArrayPtr<const char> s) const { return s; }
+  inline ArrayPtr<const char> operator*(ArrayPtr<char> s) const { return s; }
+  inline ArrayPtr<const char> operator*(const Array<const char>& s) const KJ_LIFETIMEBOUND {
+    return s;
+  }
+  inline ArrayPtr<const char> operator*(const Array<char>& s) const KJ_LIFETIMEBOUND { return s; }
+  template<size_t n>
+  inline ArrayPtr<const char> operator*(const CappedArray<char, n>& s) const KJ_LIFETIMEBOUND {
+    return s;
+  }
+  template<size_t n>
+  inline ArrayPtr<const char> operator*(const FixedArray<char, n>& s) const KJ_LIFETIMEBOUND {
+    return s;
+  }
+  inline ArrayPtr<const char> operator*(const char* s) const KJ_LIFETIMEBOUND {
+    return arrayPtr(s, strlen(s));
+  }
+#if __cpp_char8_t
+  inline ArrayPtr<const char> operator*(const char8_t* s) const KJ_LIFETIMEBOUND {
+    return operator*(reinterpret_cast<const char*>(s));
+  }
+#endif
+  inline ArrayPtr<const char> operator*(const String& s) const KJ_LIFETIMEBOUND {
+    return s.asArray();
+  }
+  inline ArrayPtr<const char> operator*(const StringPtr& s) const { return s.asArray(); }
+  inline ArrayPtr<const char> operator*(const ConstString& s) const { return s.asArray(); }
+
+  inline Range<char> operator*(const Range<char>& r) const { return r; }
+  inline Repeat<char> operator*(const Repeat<char>& r) const { return r; }
+
+  inline FixedArray<char, 1> operator*(char c) const {
+    FixedArray<char, 1> result;
+    result[0] = c;
+    return result;
+  }
+
+  StringPtr operator*(decltype(nullptr)) const;
+  StringPtr operator*(bool b) const;
+
+  CappedArray<char, 5> operator*(signed char i) const;
+  CappedArray<char, 5> operator*(unsigned char i) const;
+  CappedArray<char, sizeof(short) * 3 + 2> operator*(short i) const;
+  CappedArray<char, sizeof(unsigned short) * 3 + 2> operator*(unsigned short i) const;
+  CappedArray<char, sizeof(int) * 3 + 2> operator*(int i) const;
+  CappedArray<char, sizeof(unsigned int) * 3 + 2> operator*(unsigned int i) const;
+  CappedArray<char, sizeof(long) * 3 + 2> operator*(long i) const;
+  CappedArray<char, sizeof(unsigned long) * 3 + 2> operator*(unsigned long i) const;
+  CappedArray<char, sizeof(long long) * 3 + 2> operator*(long long i) const;
+  CappedArray<char, sizeof(unsigned long long) * 3 + 2> operator*(unsigned long long i) const;
+  CappedArray<char, 24> operator*(float f) const;
+  CappedArray<char, 32> operator*(double f) const;
+  CappedArray<char, sizeof(const void*) * 2 + 1> operator*(const void* s) const;
+
+#if KJ_COMPILER_SUPPORTS_STL_STRING_INTEROP  // supports expression SFINAE?
+  template <typename T, typename Result = decltype(instance<T>().toString())>
+  inline Result operator*(T&& value) const { return kj::fwd<T>(value).toString(); }
+#endif
+};
+static KJ_CONSTEXPR(const) Stringifier STR = Stringifier();
+
+}  // namespace _ (private)
+
+template <typename T>
+auto toCharSequence(T&& value) -> decltype(_::STR * kj::fwd<T>(value)) {
+  // Returns an iterable of chars that represent a textual representation of the value, suitable
+  // for debugging.
+  //
+  // Most users should use str() instead, but toCharSequence() may occasionally be useful to avoid
+  // heap allocation overhead that str() implies.
+  //
+  // To specialize this function for your type, see KJ_STRINGIFY.
+
+  return _::STR * kj::fwd<T>(value);
+}
+
+CappedArray<char, sizeof(unsigned char) * 2 + 1> hex(unsigned char i);
+CappedArray<char, sizeof(unsigned short) * 2 + 1> hex(unsigned short i);
+CappedArray<char, sizeof(unsigned int) * 2 + 1> hex(unsigned int i);
+CappedArray<char, sizeof(unsigned long) * 2 + 1> hex(unsigned long i);
+CappedArray<char, sizeof(unsigned long long) * 2 + 1> hex(unsigned long long i);
+
+template <typename... Params>
+String str(Params&&... params) {
+  // Magic function which builds a string from a bunch of arbitrary values.  Example:
+  //     str(1, " / ", 2, " = ", 0.5)
+  // returns:
+  //     "1 / 2 = 0.5"
+  // To teach `str` how to stringify a type, see `Stringifier`.
+
+  return _::concat(toCharSequence(kj::fwd<Params>(params))...);
+}
+
+inline String str(String&& s) { return mv(s); }
+// Overload to prevent redundant allocation.
+
+template <typename T>
+_::Delimited<T> delimited(T&& arr, kj::StringPtr delim);
+// Use to stringify an array.
+
+template <typename T>
+String strArray(T&& arr, const char* delim) {
+  size_t delimLen = strlen(delim);
+  KJ_STACK_ARRAY(decltype(_::STR * arr[0]), pieces, kj::size(arr), 8, 32);
+  size_t size = 0;
+  for (size_t i = 0; i < kj::size(arr); i++) {
+    if (i > 0) size += delimLen;
+    pieces[i] = _::STR * arr[i];
+    size += pieces[i].size();
+  }
+
+  String result = heapString(size);
+  char* pos = result.begin();
+  for (size_t i = 0; i < kj::size(arr); i++) {
+    if (i > 0) {
+      memcpy(pos, delim, delimLen);
+      pos += delimLen;
+    }
+    pos = _::fill(pos, pieces[i]);
+  }
+  return result;
+}
+
+template <typename... Params>
+StringPtr strPreallocated(ArrayPtr<char> buffer, Params&&... params) {
+  // Like str() but writes into a preallocated buffer. If the buffer is not long enough, the result
+  // is truncated (but still NUL-terminated).
+  //
+  // This can be used like:
+  //
+  //     char buffer[256];
+  //     StringPtr text = strPreallocated(buffer, params...);
+  //
+  // This is useful for optimization. It can also potentially be used safely in async signal
+  // handlers. HOWEVER, to use in an async signal handler, all of the stringifiers for the inputs
+  // must also be signal-safe. KJ guarantees signal safety when stringifying any built-in integer
+  // type (but NOT floating-points), basic char/byte sequences (ArrayPtr<byte>, String, etc.), as
+  // well as Array<T> as long as T can also be stringified safely. To safely stringify a delimited
+  // array, you must use kj::delimited(arr, delim) rather than the deprecated
+  // kj::strArray(arr, delim).
+
+  char* end = _::fillLimited(buffer.begin(), buffer.end() - 1,
+      toCharSequence(kj::fwd<Params>(params))...);
+  *end = '\0';
+  return StringPtr(buffer.begin(), end);
+}
+
+template <typename T, typename = decltype(toCharSequence(kj::instance<T&>()))>
+inline _::Delimited<ArrayPtr<T>> operator*(const _::Stringifier&, ArrayPtr<T> arr) {
+  return _::Delimited<ArrayPtr<T>>(arr, ", ");
+}
+
+template <typename T, typename = decltype(toCharSequence(kj::instance<const T&>()))>
+inline _::Delimited<ArrayPtr<const T>> operator*(const _::Stringifier&, const Array<T>& arr) {
+  return _::Delimited<ArrayPtr<const T>>(arr, ", ");
+}
+
+#define KJ_STRINGIFY(...) operator*(::kj::_::Stringifier, __VA_ARGS__)
+// Defines a stringifier for a custom type.  Example:
+//
+//    class Foo {...};
+//    inline StringPtr KJ_STRINGIFY(const Foo& foo) { return foo.name(); }
+//      // or perhaps
+//    inline String KJ_STRINGIFY(const Foo& foo) { return kj::str(foo.fld1(), ",", foo.fld2()); }
+//
+// This allows Foo to be passed to str().
+//
+// The function should be declared either in the same namespace as the target type or in the global
+// namespace.  It can return any type which is an iterable container of chars.
+
+// =======================================================================================
+// Inline implementation details.
+
+inline StringPtr::StringPtr(const String& value): content(value.cStr(), value.size() + 1) {}
+inline StringPtr::StringPtr(const ConstString& value): content(value.cStr(), value.size() + 1) {}
+
+inline constexpr StringPtr::operator ArrayPtr<const char>() const {
+  return ArrayPtr<const char>(content.begin(), content.size() - 1);
+}
+
+inline constexpr ArrayPtr<const char> StringPtr::asArray() const {
+  return ArrayPtr<const char>(content.begin(), content.size() - 1);
+}
+
+inline bool StringPtr::operator==(const StringPtr& other) const {
+  return content.size() == other.content.size() &&
+      memcmp(content.begin(), other.content.begin(), content.size() - 1) == 0;
+}
+
+inline bool StringPtr::operator<(const StringPtr& other) const {
+  bool shorter = content.size() < other.content.size();
+  int cmp = memcmp(content.begin(), other.content.begin(),
+                   shorter ? content.size() : other.content.size());
+  return cmp < 0 || (cmp == 0 && shorter);
+}
+
+inline StringPtr StringPtr::slice(size_t start) const {
+  return StringPtr(content.slice(start, content.size()));
+}
+inline ArrayPtr<const char> StringPtr::slice(size_t start, size_t end) const {
+  return content.slice(start, end);
+}
+
+inline LiteralStringConst::operator ConstString() const {
+  return ConstString(begin(), size(), NullArrayDisposer::instance);
+}
+
+inline ConstString StringPtr::attach() const {
+  // This is meant as a roundabout way to make a ConstString from a StringPtr
+  return ConstString(begin(), size(), NullArrayDisposer::instance);
+}
+
+template <typename... Attachments>
+inline ConstString StringPtr::attach(Attachments&&... attachments) const {
+  return ConstString { content.attach(kj::fwd<Attachments>(attachments)...) };
+}
+
+inline String::operator ArrayPtr<char>() {
+  return content == nullptr ? ArrayPtr<char>(nullptr) : content.slice(0, content.size() - 1);
+}
+inline String::operator ArrayPtr<const char>() const {
+  return content == nullptr ? ArrayPtr<const char>(nullptr) : content.slice(0, content.size() - 1);
+}
+inline ConstString::operator ArrayPtr<const char>() const {
+  return content == nullptr ? ArrayPtr<const char>(nullptr) : content.slice(0, content.size() - 1);
+}
+
+inline ArrayPtr<char> String::asArray() {
+  return content == nullptr ? ArrayPtr<char>(nullptr) : content.slice(0, content.size() - 1);
+}
+inline ArrayPtr<const char> String::asArray() const {
+  return content == nullptr ? ArrayPtr<const char>(nullptr) : content.slice(0, content.size() - 1);
+}
+inline ArrayPtr<const char> ConstString::asArray() const {
+  return content == nullptr ? ArrayPtr<const char>(nullptr) : content.slice(0, content.size() - 1);
+}
+
+inline const char* String::cStr() const { return content == nullptr ? "" : content.begin(); }
+inline const char* ConstString::cStr() const { return content == nullptr ? "" : content.begin(); }
+
+inline size_t String::size() const { return content == nullptr ? 0 : content.size() - 1; }
+inline size_t ConstString::size() const { return content == nullptr ? 0 : content.size() - 1; }
+
+inline char String::operator[](size_t index) const { return content[index]; }
+inline char& String::operator[](size_t index) { return content[index]; }
+inline char ConstString::operator[](size_t index) const { return content[index]; }
+
+inline char* String::begin() { return content == nullptr ? nullptr : content.begin(); }
+inline char* String::end() { return content == nullptr ? nullptr : content.end() - 1; }
+inline const char* String::begin() const { return content == nullptr ? nullptr : content.begin(); }
+inline const char* String::end() const { return content == nullptr ? nullptr : content.end() - 1; }
+inline const char* ConstString::begin() const { return content == nullptr ? nullptr : content.begin(); }
+inline const char* ConstString::end() const { return content == nullptr ? nullptr : content.end() - 1; }
+
+inline String::String(char* value, size_t size, const ArrayDisposer& disposer)
+    : content(value, size + 1, disposer) {
+  KJ_IREQUIRE(value[size] == '\0', "String must be NUL-terminated.");
+}
+inline ConstString::ConstString(const char* value, size_t size, const ArrayDisposer& disposer)
+    : content(value, size + 1, disposer) {
+  KJ_IREQUIRE(value[size] == '\0', "String must be NUL-terminated.");
+}
+
+inline String::String(Array<char> buffer): content(kj::mv(buffer)) {
+  KJ_IREQUIRE(content.size() > 0 && content.back() == '\0', "String must be NUL-terminated.");
+}
+inline ConstString::ConstString(Array<const char> buffer): content(kj::mv(buffer)) {
+  KJ_IREQUIRE(content.size() > 0 && content.back() == '\0', "String must be NUL-terminated.");
+}
+
+inline String heapString(const char* value) {
+  return heapString(value, strlen(value));
+}
+inline String heapString(StringPtr value) {
+  return heapString(value.begin(), value.size());
+}
+inline String heapString(const String& value) {
+  return heapString(value.begin(), value.size());
+}
+inline String heapString(ArrayPtr<const char> value) {
+  return heapString(value.begin(), value.size());
+}
+
+namespace _ {  // private
+
+template <typename T>
+class Delimited {
+public:
+  Delimited(T array, kj::StringPtr delimiter)
+      : array(kj::fwd<T>(array)), delimiter(delimiter) {}
+
+  // TODO(someday): In theory we should support iteration as a character sequence, but the iterator
+  //   will be pretty complicated.
+
+  size_t size() {
+    ensureStringifiedInitialized();
+
+    size_t result = 0;
+    bool first = true;
+    for (auto& e: stringified) {
+      if (first) {
+        first = false;
+      } else {
+        result += delimiter.size();
+      }
+      result += e.size();
+    }
+    return result;
+  }
+
+  char* flattenTo(char* __restrict__ target) {
+    ensureStringifiedInitialized();
+
+    bool first = true;
+    for (auto& elem: stringified) {
+      if (first) {
+        first = false;
+      } else {
+        target = fill(target, delimiter);
+      }
+      target = fill(target, elem);
+    }
+    return target;
+  }
+
+  char* flattenTo(char* __restrict__ target, char* limit) {
+    // This is called in the strPreallocated(). We want to avoid allocation. size() will not have
+    // been called in this case, so hopefully `stringified` is still uninitialized. We will
+    // stringify each item and immediately use it.
+    bool first = true;
+    for (auto&& elem: array) {
+      if (target == limit) return target;
+      if (first) {
+        first = false;
+      } else {
+        target = fillLimited(target, limit, delimiter);
+      }
+      target = fillLimited(target, limit, kj::toCharSequence(elem));
+    }
+    return target;
+  }
+
+private:
+  typedef decltype(toCharSequence(*instance<T>().begin())) StringifiedItem;
+  T array;
+  kj::StringPtr delimiter;
+  Array<StringifiedItem> stringified;
+
+  void ensureStringifiedInitialized() {
+    if (array.size() > 0 && stringified.size() == 0) {
+      stringified = KJ_MAP(e, array) { return toCharSequence(e); };
+    }
+  }
+};
+
+template <typename T, typename... Rest>
+char* fill(char* __restrict__ target, Delimited<T>&& first, Rest&&... rest) {
+  target = first.flattenTo(target);
+  return fill(target, kj::fwd<Rest>(rest)...);
+}
+template <typename T, typename... Rest>
+char* fillLimited(char* __restrict__ target, char* limit, Delimited<T>&& first, Rest&&... rest) {
+  target = first.flattenTo(target, limit);
+  return fillLimited(target, limit, kj::fwd<Rest>(rest)...);
+}
+template <typename T, typename... Rest>
+char* fill(char* __restrict__ target, Delimited<T>& first, Rest&&... rest) {
+  target = first.flattenTo(target);
+  return fill(target, kj::fwd<Rest>(rest)...);
+}
+template <typename T, typename... Rest>
+char* fillLimited(char* __restrict__ target, char* limit, Delimited<T>& first, Rest&&... rest) {
+  target = first.flattenTo(target, limit);
+  return fillLimited(target, limit, kj::fwd<Rest>(rest)...);
+}
+
+template <typename T>
+inline Delimited<T>&& KJ_STRINGIFY(Delimited<T>&& delimited) { return kj::mv(delimited); }
+template <typename T>
+inline const Delimited<T>& KJ_STRINGIFY(const Delimited<T>& delimited) { return delimited; }
+
+}  // namespace _ (private)
+
+template <typename T>
+_::Delimited<T> delimited(T&& arr, kj::StringPtr delim) {
+  return _::Delimited<T>(kj::fwd<T>(arr), delim);
+}
+
+}  // namespace kj
+
+constexpr kj::StringPtr operator "" _kj(const char* str, size_t n) {
+  return kj::StringPtr(kj::ArrayPtr<const char>(str, n + 1));
+};
+
+constexpr kj::LiteralStringConst operator "" _kjc(const char* str, size_t n) {
+  return kj::LiteralStringConst(kj::ArrayPtr<const char>(str, n + 1));
+};
+
+KJ_END_HEADER