Chris@47: // Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
Chris@47: // Licensed under the MIT License:
Chris@47: //
Chris@47: // Permission is hereby granted, free of charge, to any person obtaining a copy
Chris@47: // of this software and associated documentation files (the "Software"), to deal
Chris@47: // in the Software without restriction, including without limitation the rights
Chris@47: // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
Chris@47: // copies of the Software, and to permit persons to whom the Software is
Chris@47: // furnished to do so, subject to the following conditions:
Chris@47: //
Chris@47: // The above copyright notice and this permission notice shall be included in
Chris@47: // all copies or substantial portions of the Software.
Chris@47: //
Chris@47: // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
Chris@47: // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
Chris@47: // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
Chris@47: // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
Chris@47: // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
Chris@47: // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
Chris@47: // THE SOFTWARE.
Chris@47: 
Chris@47: // This file contains types which are intended to help detect incorrect usage at compile
Chris@47: // time, but should then be optimized down to basic primitives (usually, integers) by the
Chris@47: // compiler.
Chris@47: 
Chris@47: #ifndef CAPNP_COMMON_H_
Chris@47: #define CAPNP_COMMON_H_
Chris@47: 
Chris@47: #if defined(__GNUC__) && !defined(CAPNP_HEADER_WARNINGS)
Chris@47: #pragma GCC system_header
Chris@47: #endif
Chris@47: 
Chris@47: #include <kj/units.h>
Chris@47: #include <inttypes.h>
Chris@47: #include <kj/string.h>
Chris@47: #include <kj/memory.h>
Chris@47: 
Chris@47: namespace capnp {
Chris@47: 
Chris@47: #define CAPNP_VERSION_MAJOR 0
Chris@47: #define CAPNP_VERSION_MINOR 6
Chris@47: #define CAPNP_VERSION_MICRO 0
Chris@47: 
Chris@47: #define CAPNP_VERSION \
Chris@47:   (CAPNP_VERSION_MAJOR * 1000000 + CAPNP_VERSION_MINOR * 1000 + CAPNP_VERSION_MICRO)
Chris@47: 
Chris@47: #ifdef _MSC_VER
Chris@47: #define CAPNP_LITE 1
Chris@47: // MSVC only supports "lite" mode for now, due to missing C++11 features.
Chris@47: #endif
Chris@47: 
Chris@47: #ifndef CAPNP_LITE
Chris@47: #define CAPNP_LITE 0
Chris@47: #endif
Chris@47: 
Chris@47: typedef unsigned int uint;
Chris@47: 
Chris@47: struct Void {
Chris@47:   // Type used for Void fields.  Using C++'s "void" type creates a bunch of issues since it behaves
Chris@47:   // differently from other types.
Chris@47: 
Chris@47:   inline constexpr bool operator==(Void other) const { return true; }
Chris@47:   inline constexpr bool operator!=(Void other) const { return false; }
Chris@47: };
Chris@47: 
Chris@47: static constexpr Void VOID = Void();
Chris@47: // Constant value for `Void`,  which is an empty struct.
Chris@47: 
Chris@47: inline kj::StringPtr KJ_STRINGIFY(Void) { return "void"; }
Chris@47: 
Chris@47: struct Text;
Chris@47: struct Data;
Chris@47: 
Chris@47: enum class Kind: uint8_t {
Chris@47:   PRIMITIVE,
Chris@47:   BLOB,
Chris@47:   ENUM,
Chris@47:   STRUCT,
Chris@47:   UNION,
Chris@47:   INTERFACE,
Chris@47:   LIST,
Chris@47: 
Chris@47:   OTHER
Chris@47:   // Some other type which is often a type parameter to Cap'n Proto templates, but which needs
Chris@47:   // special handling. This includes types like AnyPointer, Dynamic*, etc.
Chris@47: };
Chris@47: 
Chris@47: enum class Style: uint8_t {
Chris@47:   PRIMITIVE,
Chris@47:   POINTER,      // other than struct
Chris@47:   STRUCT,
Chris@47:   CAPABILITY
Chris@47: };
Chris@47: 
Chris@47: enum class ElementSize: uint8_t {
Chris@47:   // Size of a list element.
Chris@47: 
Chris@47:   VOID = 0,
Chris@47:   BIT = 1,
Chris@47:   BYTE = 2,
Chris@47:   TWO_BYTES = 3,
Chris@47:   FOUR_BYTES = 4,
Chris@47:   EIGHT_BYTES = 5,
Chris@47: 
Chris@47:   POINTER = 6,
Chris@47: 
Chris@47:   INLINE_COMPOSITE = 7
Chris@47: };
Chris@47: 
Chris@47: enum class PointerType {
Chris@47:   // Various wire types a pointer field can take
Chris@47: 
Chris@47:   NULL_,
Chris@47:   // Should be NULL, but that's #defined in stddef.h
Chris@47: 
Chris@47:   STRUCT,
Chris@47:   LIST,
Chris@47:   CAPABILITY
Chris@47: };
Chris@47: 
Chris@47: namespace schemas {
Chris@47: 
Chris@47: template <typename T>
Chris@47: struct EnumInfo;
Chris@47: 
Chris@47: }  // namespace schemas
Chris@47: 
Chris@47: namespace _ {  // private
Chris@47: 
Chris@47: template <typename T, typename = void> struct Kind_;
Chris@47: 
Chris@47: template <> struct Kind_<Void> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<bool> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<int8_t> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<int16_t> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<int32_t> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<int64_t> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<uint8_t> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<uint16_t> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<uint32_t> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<uint64_t> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<float> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<double> { static constexpr Kind kind = Kind::PRIMITIVE; };
Chris@47: template <> struct Kind_<Text> { static constexpr Kind kind = Kind::BLOB; };
Chris@47: template <> struct Kind_<Data> { static constexpr Kind kind = Kind::BLOB; };
Chris@47: 
Chris@47: template <typename T> struct Kind_<T, kj::VoidSfinae<typename T::_capnpPrivate::IsStruct>> {
Chris@47:   static constexpr Kind kind = Kind::STRUCT;
Chris@47: };
Chris@47: template <typename T> struct Kind_<T, kj::VoidSfinae<typename T::_capnpPrivate::IsInterface>> {
Chris@47:   static constexpr Kind kind = Kind::INTERFACE;
Chris@47: };
Chris@47: template <typename T> struct Kind_<T, kj::VoidSfinae<typename schemas::EnumInfo<T>::IsEnum>> {
Chris@47:   static constexpr Kind kind = Kind::ENUM;
Chris@47: };
Chris@47: 
Chris@47: }  // namespace _ (private)
Chris@47: 
Chris@47: template <typename T, Kind k = _::Kind_<T>::kind>
Chris@47: inline constexpr Kind kind() {
Chris@47:   // This overload of kind() matches types which have a Kind_ specialization.
Chris@47: 
Chris@47:   return k;
Chris@47: }
Chris@47: 
Chris@47: #if CAPNP_LITE
Chris@47: 
Chris@47: #define CAPNP_KIND(T) ::capnp::_::Kind_<T>::kind
Chris@47: // Avoid constexpr methods in lite mode (MSVC is bad at constexpr).
Chris@47: 
Chris@47: #else  // CAPNP_LITE
Chris@47: 
Chris@47: #define CAPNP_KIND(T) ::capnp::kind<T>()
Chris@47: // Use this macro rather than kind<T>() in any code which must work in lite mode.
Chris@47: 
Chris@47: template <typename T, Kind k = kind<T>()>
Chris@47: inline constexpr Style style() {
Chris@47:   return k == Kind::PRIMITIVE || k == Kind::ENUM ? Style::PRIMITIVE
Chris@47:        : k == Kind::STRUCT ? Style::STRUCT
Chris@47:        : k == Kind::INTERFACE ? Style::CAPABILITY : Style::POINTER;
Chris@47: }
Chris@47: 
Chris@47: #endif  // CAPNP_LITE, else
Chris@47: 
Chris@47: template <typename T, Kind k = CAPNP_KIND(T)>
Chris@47: struct List;
Chris@47: 
Chris@47: #if _MSC_VER
Chris@47: 
Chris@47: template <typename T, Kind k>
Chris@47: struct List {};
Chris@47: // For some reason, without this declaration, MSVC will error out on some uses of List
Chris@47: // claiming that "T" -- as used in the default initializer for the second template param, "k" --
Chris@47: // is not defined. I do not understand this error, but adding this empty default declaration fixes
Chris@47: // it.
Chris@47: 
Chris@47: #endif
Chris@47: 
Chris@47: template <typename T> struct ListElementType_;
Chris@47: template <typename T> struct ListElementType_<List<T>> { typedef T Type; };
Chris@47: template <typename T> using ListElementType = typename ListElementType_<T>::Type;
Chris@47: 
Chris@47: namespace _ {  // private
Chris@47: template <typename T, Kind k> struct Kind_<List<T, k>> {
Chris@47:   static constexpr Kind kind = Kind::LIST;
Chris@47: };
Chris@47: }  // namespace _ (private)
Chris@47: 
Chris@47: template <typename T, Kind k = CAPNP_KIND(T)> struct ReaderFor_ { typedef typename T::Reader Type; };
Chris@47: template <typename T> struct ReaderFor_<T, Kind::PRIMITIVE> { typedef T Type; };
Chris@47: template <typename T> struct ReaderFor_<T, Kind::ENUM> { typedef T Type; };
Chris@47: template <typename T> struct ReaderFor_<T, Kind::INTERFACE> { typedef typename T::Client Type; };
Chris@47: template <typename T> using ReaderFor = typename ReaderFor_<T>::Type;
Chris@47: // The type returned by List<T>::Reader::operator[].
Chris@47: 
Chris@47: template <typename T, Kind k = CAPNP_KIND(T)> struct BuilderFor_ { typedef typename T::Builder Type; };
Chris@47: template <typename T> struct BuilderFor_<T, Kind::PRIMITIVE> { typedef T Type; };
Chris@47: template <typename T> struct BuilderFor_<T, Kind::ENUM> { typedef T Type; };
Chris@47: template <typename T> struct BuilderFor_<T, Kind::INTERFACE> { typedef typename T::Client Type; };
Chris@47: template <typename T> using BuilderFor = typename BuilderFor_<T>::Type;
Chris@47: // The type returned by List<T>::Builder::operator[].
Chris@47: 
Chris@47: template <typename T, Kind k = CAPNP_KIND(T)> struct PipelineFor_ { typedef typename T::Pipeline Type;};
Chris@47: template <typename T> struct PipelineFor_<T, Kind::INTERFACE> { typedef typename T::Client Type; };
Chris@47: template <typename T> using PipelineFor = typename PipelineFor_<T>::Type;
Chris@47: 
Chris@47: template <typename T, Kind k = CAPNP_KIND(T)> struct TypeIfEnum_;
Chris@47: template <typename T> struct TypeIfEnum_<T, Kind::ENUM> { typedef T Type; };
Chris@47: 
Chris@47: template <typename T>
Chris@47: using TypeIfEnum = typename TypeIfEnum_<kj::Decay<T>>::Type;
Chris@47: 
Chris@47: template <typename T>
Chris@47: using FromReader = typename kj::Decay<T>::Reads;
Chris@47: // FromReader<MyType::Reader> = MyType (for any Cap'n Proto type).
Chris@47: 
Chris@47: template <typename T>
Chris@47: using FromBuilder = typename kj::Decay<T>::Builds;
Chris@47: // FromBuilder<MyType::Builder> = MyType (for any Cap'n Proto type).
Chris@47: 
Chris@47: template <typename T>
Chris@47: using FromPipeline = typename kj::Decay<T>::Pipelines;
Chris@47: // FromBuilder<MyType::Pipeline> = MyType (for any Cap'n Proto type).
Chris@47: 
Chris@47: template <typename T>
Chris@47: using FromClient = typename kj::Decay<T>::Calls;
Chris@47: // FromReader<MyType::Client> = MyType (for any Cap'n Proto interface type).
Chris@47: 
Chris@47: template <typename T>
Chris@47: using FromServer = typename kj::Decay<T>::Serves;
Chris@47: // FromBuilder<MyType::Server> = MyType (for any Cap'n Proto interface type).
Chris@47: 
Chris@47: template <typename T, typename = void>
Chris@47: struct FromAny_;
Chris@47: 
Chris@47: template <typename T>
Chris@47: struct FromAny_<T, kj::VoidSfinae<FromReader<T>>> {
Chris@47:   using Type = FromReader<T>;
Chris@47: };
Chris@47: 
Chris@47: template <typename T>
Chris@47: struct FromAny_<T, kj::VoidSfinae<FromBuilder<T>>> {
Chris@47:   using Type = FromBuilder<T>;
Chris@47: };
Chris@47: 
Chris@47: template <typename T>
Chris@47: struct FromAny_<T, kj::VoidSfinae<FromPipeline<T>>> {
Chris@47:   using Type = FromPipeline<T>;
Chris@47: };
Chris@47: 
Chris@47: // Note that T::Client is covered by FromReader
Chris@47: 
Chris@47: template <typename T>
Chris@47: struct FromAny_<kj::Own<T>, kj::VoidSfinae<FromServer<T>>> {
Chris@47:   using Type = FromServer<T>;
Chris@47: };
Chris@47: 
Chris@47: template <typename T>
Chris@47: struct FromAny_<T,
Chris@47:     kj::EnableIf<_::Kind_<T>::kind == Kind::PRIMITIVE || _::Kind_<T>::kind == Kind::ENUM>> {
Chris@47:   // TODO(msvc): Ideally the EnableIf condition would be `style<T>() == Style::PRIMITIVE`, but MSVC
Chris@47:   // cannot yet use style<T>() in this constexpr context.
Chris@47: 
Chris@47:   using Type = kj::Decay<T>;
Chris@47: };
Chris@47: 
Chris@47: template <typename T>
Chris@47: using FromAny = typename FromAny_<T>::Type;
Chris@47: // Given any Cap'n Proto value type as an input, return the Cap'n Proto base type. That is:
Chris@47: //
Chris@47: //     Foo::Reader -> Foo
Chris@47: //     Foo::Builder -> Foo
Chris@47: //     Foo::Pipeline -> Foo
Chris@47: //     Foo::Client -> Foo
Chris@47: //     Own<Foo::Server> -> Foo
Chris@47: //     uint32_t -> uint32_t
Chris@47: 
Chris@47: namespace _ {  // private
Chris@47: 
Chris@47: template <typename T, Kind k = CAPNP_KIND(T)>
Chris@47: struct PointerHelpers;
Chris@47: 
Chris@47: #if _MSC_VER
Chris@47: 
Chris@47: template <typename T, Kind k>
Chris@47: struct PointerHelpers {};
Chris@47: // For some reason, without this declaration, MSVC will error out on some uses of PointerHelpers
Chris@47: // claiming that "T" -- as used in the default initializer for the second template param, "k" --
Chris@47: // is not defined. I do not understand this error, but adding this empty default declaration fixes
Chris@47: // it.
Chris@47: 
Chris@47: #endif
Chris@47: 
Chris@47: }  // namespace _ (private)
Chris@47: 
Chris@47: struct MessageSize {
Chris@47:   // Size of a message.  Every struct type has a method `.totalSize()` that returns this.
Chris@47:   uint64_t wordCount;
Chris@47:   uint capCount;
Chris@47: };
Chris@47: 
Chris@47: // =======================================================================================
Chris@47: // Raw memory types and measures
Chris@47: 
Chris@47: using kj::byte;
Chris@47: 
Chris@47: class word { uint64_t content KJ_UNUSED_MEMBER; KJ_DISALLOW_COPY(word); public: word() = default; };
Chris@47: // word is an opaque type with size of 64 bits.  This type is useful only to make pointer
Chris@47: // arithmetic clearer.  Since the contents are private, the only way to access them is to first
Chris@47: // reinterpret_cast to some other pointer type.
Chris@47: //
Chris@47: // Copying is disallowed because you should always use memcpy().  Otherwise, you may run afoul of
Chris@47: // aliasing rules.
Chris@47: //
Chris@47: // A pointer of type word* should always be word-aligned even if won't actually be dereferenced as
Chris@47: // that type.
Chris@47: 
Chris@47: static_assert(sizeof(byte) == 1, "uint8_t is not one byte?");
Chris@47: static_assert(sizeof(word) == 8, "uint64_t is not 8 bytes?");
Chris@47: 
Chris@47: #if CAPNP_DEBUG_TYPES
Chris@47: // Set CAPNP_DEBUG_TYPES to 1 to use kj::Quantity for "count" types.  Otherwise, plain integers are
Chris@47: // used.  All the code should still operate exactly the same, we just lose compile-time checking.
Chris@47: // Note that this will also change symbol names, so it's important that the library and any clients
Chris@47: // be compiled with the same setting here.
Chris@47: //
Chris@47: // We disable this by default to reduce symbol name size and avoid any possibility of the compiler
Chris@47: // failing to fully-optimize the types, but anyone modifying Cap'n Proto itself should enable this
Chris@47: // during development and testing.
Chris@47: 
Chris@47: namespace _ { class BitLabel; class ElementLabel; struct WirePointer; }
Chris@47: 
Chris@47: typedef kj::Quantity<uint, _::BitLabel> BitCount;
Chris@47: typedef kj::Quantity<uint8_t, _::BitLabel> BitCount8;
Chris@47: typedef kj::Quantity<uint16_t, _::BitLabel> BitCount16;
Chris@47: typedef kj::Quantity<uint32_t, _::BitLabel> BitCount32;
Chris@47: typedef kj::Quantity<uint64_t, _::BitLabel> BitCount64;
Chris@47: 
Chris@47: typedef kj::Quantity<uint, byte> ByteCount;
Chris@47: typedef kj::Quantity<uint8_t, byte> ByteCount8;
Chris@47: typedef kj::Quantity<uint16_t, byte> ByteCount16;
Chris@47: typedef kj::Quantity<uint32_t, byte> ByteCount32;
Chris@47: typedef kj::Quantity<uint64_t, byte> ByteCount64;
Chris@47: 
Chris@47: typedef kj::Quantity<uint, word> WordCount;
Chris@47: typedef kj::Quantity<uint8_t, word> WordCount8;
Chris@47: typedef kj::Quantity<uint16_t, word> WordCount16;
Chris@47: typedef kj::Quantity<uint32_t, word> WordCount32;
Chris@47: typedef kj::Quantity<uint64_t, word> WordCount64;
Chris@47: 
Chris@47: typedef kj::Quantity<uint, _::ElementLabel> ElementCount;
Chris@47: typedef kj::Quantity<uint8_t, _::ElementLabel> ElementCount8;
Chris@47: typedef kj::Quantity<uint16_t, _::ElementLabel> ElementCount16;
Chris@47: typedef kj::Quantity<uint32_t, _::ElementLabel> ElementCount32;
Chris@47: typedef kj::Quantity<uint64_t, _::ElementLabel> ElementCount64;
Chris@47: 
Chris@47: typedef kj::Quantity<uint, _::WirePointer> WirePointerCount;
Chris@47: typedef kj::Quantity<uint8_t, _::WirePointer> WirePointerCount8;
Chris@47: typedef kj::Quantity<uint16_t, _::WirePointer> WirePointerCount16;
Chris@47: typedef kj::Quantity<uint32_t, _::WirePointer> WirePointerCount32;
Chris@47: typedef kj::Quantity<uint64_t, _::WirePointer> WirePointerCount64;
Chris@47: 
Chris@47: template <typename T, typename U>
Chris@47: inline constexpr U* operator+(U* ptr, kj::Quantity<T, U> offset) {
Chris@47:   return ptr + offset / kj::unit<kj::Quantity<T, U>>();
Chris@47: }
Chris@47: template <typename T, typename U>
Chris@47: inline constexpr const U* operator+(const U* ptr, kj::Quantity<T, U> offset) {
Chris@47:   return ptr + offset / kj::unit<kj::Quantity<T, U>>();
Chris@47: }
Chris@47: template <typename T, typename U>
Chris@47: inline constexpr U* operator+=(U*& ptr, kj::Quantity<T, U> offset) {
Chris@47:   return ptr = ptr + offset / kj::unit<kj::Quantity<T, U>>();
Chris@47: }
Chris@47: template <typename T, typename U>
Chris@47: inline constexpr const U* operator+=(const U*& ptr, kj::Quantity<T, U> offset) {
Chris@47:   return ptr = ptr + offset / kj::unit<kj::Quantity<T, U>>();
Chris@47: }
Chris@47: 
Chris@47: template <typename T, typename U>
Chris@47: inline constexpr U* operator-(U* ptr, kj::Quantity<T, U> offset) {
Chris@47:   return ptr - offset / kj::unit<kj::Quantity<T, U>>();
Chris@47: }
Chris@47: template <typename T, typename U>
Chris@47: inline constexpr const U* operator-(const U* ptr, kj::Quantity<T, U> offset) {
Chris@47:   return ptr - offset / kj::unit<kj::Quantity<T, U>>();
Chris@47: }
Chris@47: template <typename T, typename U>
Chris@47: inline constexpr U* operator-=(U*& ptr, kj::Quantity<T, U> offset) {
Chris@47:   return ptr = ptr - offset / kj::unit<kj::Quantity<T, U>>();
Chris@47: }
Chris@47: template <typename T, typename U>
Chris@47: inline constexpr const U* operator-=(const U*& ptr, kj::Quantity<T, U> offset) {
Chris@47:   return ptr = ptr - offset / kj::unit<kj::Quantity<T, U>>();
Chris@47: }
Chris@47: 
Chris@47: #else
Chris@47: 
Chris@47: typedef uint BitCount;
Chris@47: typedef uint8_t BitCount8;
Chris@47: typedef uint16_t BitCount16;
Chris@47: typedef uint32_t BitCount32;
Chris@47: typedef uint64_t BitCount64;
Chris@47: 
Chris@47: typedef uint ByteCount;
Chris@47: typedef uint8_t ByteCount8;
Chris@47: typedef uint16_t ByteCount16;
Chris@47: typedef uint32_t ByteCount32;
Chris@47: typedef uint64_t ByteCount64;
Chris@47: 
Chris@47: typedef uint WordCount;
Chris@47: typedef uint8_t WordCount8;
Chris@47: typedef uint16_t WordCount16;
Chris@47: typedef uint32_t WordCount32;
Chris@47: typedef uint64_t WordCount64;
Chris@47: 
Chris@47: typedef uint ElementCount;
Chris@47: typedef uint8_t ElementCount8;
Chris@47: typedef uint16_t ElementCount16;
Chris@47: typedef uint32_t ElementCount32;
Chris@47: typedef uint64_t ElementCount64;
Chris@47: 
Chris@47: typedef uint WirePointerCount;
Chris@47: typedef uint8_t WirePointerCount8;
Chris@47: typedef uint16_t WirePointerCount16;
Chris@47: typedef uint32_t WirePointerCount32;
Chris@47: typedef uint64_t WirePointerCount64;
Chris@47: 
Chris@47: #endif
Chris@47: 
Chris@47: constexpr BitCount BITS = kj::unit<BitCount>();
Chris@47: constexpr ByteCount BYTES = kj::unit<ByteCount>();
Chris@47: constexpr WordCount WORDS = kj::unit<WordCount>();
Chris@47: constexpr ElementCount ELEMENTS = kj::unit<ElementCount>();
Chris@47: constexpr WirePointerCount POINTERS = kj::unit<WirePointerCount>();
Chris@47: 
Chris@47: // GCC 4.7 actually gives unused warnings on these constants in opt mode...
Chris@47: constexpr auto BITS_PER_BYTE KJ_UNUSED = 8 * BITS / BYTES;
Chris@47: constexpr auto BITS_PER_WORD KJ_UNUSED = 64 * BITS / WORDS;
Chris@47: constexpr auto BYTES_PER_WORD KJ_UNUSED = 8 * BYTES / WORDS;
Chris@47: 
Chris@47: constexpr auto BITS_PER_POINTER KJ_UNUSED = 64 * BITS / POINTERS;
Chris@47: constexpr auto BYTES_PER_POINTER KJ_UNUSED = 8 * BYTES / POINTERS;
Chris@47: constexpr auto WORDS_PER_POINTER KJ_UNUSED = 1 * WORDS / POINTERS;
Chris@47: 
Chris@47: constexpr WordCount POINTER_SIZE_IN_WORDS = 1 * POINTERS * WORDS_PER_POINTER;
Chris@47: 
Chris@47: template <typename T>
Chris@47: inline KJ_CONSTEXPR() decltype(BYTES / ELEMENTS) bytesPerElement() {
Chris@47:   return sizeof(T) * BYTES / ELEMENTS;
Chris@47: }
Chris@47: 
Chris@47: template <typename T>
Chris@47: inline KJ_CONSTEXPR() decltype(BITS / ELEMENTS) bitsPerElement() {
Chris@47:   return sizeof(T) * 8 * BITS / ELEMENTS;
Chris@47: }
Chris@47: 
Chris@47: inline constexpr ByteCount intervalLength(const byte* a, const byte* b) {
Chris@47:   return uint(b - a) * BYTES;
Chris@47: }
Chris@47: inline constexpr WordCount intervalLength(const word* a, const word* b) {
Chris@47:   return uint(b - a) * WORDS;
Chris@47: }
Chris@47: 
Chris@47: }  // namespace capnp
Chris@47: 
Chris@47: #endif  // CAPNP_COMMON_H_