fs: reduce path size 0x28 -> 0x18

libraries/libstratosphere/include/stratosphere/fs/fs_memory_management.hpp

@@ -18,6 +18,9 @@
 
 namespace ams::fs {
 
+    /* Controls whether MakeUniqueBuffer uses a custom buffer wrapper which wraps the size inline. */
+    #define AMS_FS_IMPL_MAKE_UNIQUE_BUFFER_WITH_INLINE_SIZE
+
     /* ACCURATE_TO_VERSION: Unknown */
     using AllocateFunction   = void *(*)(size_t);
     using DeallocateFunction = void (*)(void *, size_t);
@@ -26,6 +29,8 @@ namespace ams::fs {
 
     namespace impl {
 
+        class Newable;
+
         void *Allocate(size_t size);
         void Deallocate(void *ptr, size_t size);
 
@@ -129,21 +134,175 @@ namespace ams::fs {
                 }
         };
 
+        #if defined(AMS_FS_IMPL_MAKE_UNIQUE_BUFFER_WITH_INLINE_SIZE)
+        template<std::convertible_to<u8> BufferEntryType>
+        class BufferWithInlineSize final {
+            static_assert(sizeof(BufferEntryType) == 1);
+            NON_COPYABLE(BufferWithInlineSize);
+            NON_MOVEABLE(BufferWithInlineSize);
+            private:
+                template<std::unsigned_integral T> static constexpr inline T EncodedSizeMask = util::IsLittleEndian() ? (static_cast<T>(3u) << (BITSIZEOF(T) - 2)) : static_cast<T>(3u);
+
+                template<std::unsigned_integral T> static constexpr inline T EncodedSize1    = util::IsLittleEndian() ? (static_cast<T>(0u) << (BITSIZEOF(T) - 2)) : static_cast<T>(0u);
+                template<std::unsigned_integral T> static constexpr inline T EncodedSize2    = util::IsLittleEndian() ? (static_cast<T>(1u) << (BITSIZEOF(T) - 2)) : static_cast<T>(1u);
+                template<std::unsigned_integral T> static constexpr inline T EncodedSize4    = util::IsLittleEndian() ? (static_cast<T>(2u) << (BITSIZEOF(T) - 2)) : static_cast<T>(2u);
+                template<std::unsigned_integral T> static constexpr inline T EncodedSize8    = util::IsLittleEndian() ? (static_cast<T>(3u) << (BITSIZEOF(T) - 2)) : static_cast<T>(3u);
+
+                static constexpr inline u64 TestSize1Mask = ~((static_cast<u64>(1u) << (BITSIZEOF(u8)  - 2)) - static_cast<u64>(1));
+                static constexpr inline u64 TestSize2Mask = ~((static_cast<u64>(1u) << (BITSIZEOF(u16) - 2)) - static_cast<u64>(1));
+                static constexpr inline u64 TestSize4Mask = ~((static_cast<u64>(1u) << (BITSIZEOF(u32) - 2)) - static_cast<u64>(1));
+                static constexpr inline u64 TestSize8Mask = ~((static_cast<u64>(1u) << (BITSIZEOF(u64) - 2)) - static_cast<u64>(1));
+
+                template<std::unsigned_integral SizeType>
+                static constexpr ALWAYS_INLINE SizeType EncodeSize(SizeType type, size_t size) noexcept {
+                    if constexpr (util::IsLittleEndian()) {
+                        return type | static_cast<SizeType>(size);
+                    } else {
+                        return type | (static_cast<SizeType>(size) << 2);
+                    }
+                }
+
+                template<std::unsigned_integral SizeType>
+                static constexpr ALWAYS_INLINE size_t DecodeSize(const SizeType encoded) noexcept {
+                    if constexpr (util::IsLittleEndian()) {
+                        /* Small optimization: 1-byte size has size type field == 0 and no shifting, can return the value directly. */
+                        if constexpr (sizeof(SizeType) == 1) {
+                            static_assert(EncodedSize1<SizeType> == 0);
+                            return encoded;
+                        } else {
+                            /* On little endian, we want to mask out the high bits storing the size field. */
+                            constexpr SizeType DecodedSizeMask = static_cast<SizeType>(~EncodedSizeMask<SizeType>);
+
+                            return encoded & DecodedSizeMask;
+                        }
+                    } else {
+                        /* On big endian, we want to shift out the low bits storing the size type field. */
+                        return encoded >> 2;
+                    }
+                }
+
+                template<std::unsigned_integral SizeType>
+                static ALWAYS_INLINE void DeleteBufferImpl(BufferEntryType *buffer) noexcept {
+                    /* Get pointer to start of allocation. */
+                    SizeType *alloc = reinterpret_cast<SizeType *>(buffer) - 1;
+
+                    /* Decode the size of the allocation. */
+                    const size_t alloc_size = sizeof(SizeType) + DecodeSize<SizeType>(*alloc);
+
+                    /* Delete the buffer. */
+                    return ::ams::fs::impl::Deallocate(alloc, alloc_size);
+                }
+
+                template<std::unsigned_integral SizeType, SizeType EncodedSizeType>
+                static std::unique_ptr<BufferWithInlineSize> MakeBuffer(size_t size) noexcept {
+                    /* Allocate a buffer. */
+                    SizeType *alloc = static_cast<SizeType *>(::ams::fs::impl::Allocate(sizeof(SizeType) + size));
+                    if (AMS_UNLIKELY(alloc == nullptr)) {
+                        return nullptr;
+                    }
+
+                    /* Write the encoded size. */
+                    if constexpr (util::IsLittleEndian()) {
+                        *alloc = EncodedSizeType | static_cast<SizeType>(size);
+                    } else {
+                        *alloc = EncodedSizeType | (static_cast<SizeType>(size) << 2);
+                    }
+
+                    /* Return our buffer. */
+                    return std::unique_ptr<BufferWithInlineSize>(reinterpret_cast<BufferWithInlineSize *>(alloc + 1));
+                }
+
+                static void DeleteBuffer(BufferEntryType *buffer) noexcept {
+                    /* Convert to u8 pointer */
+                    const u8 *buffer_u8 = reinterpret_cast<const u8 *>(buffer);
+
+                    /* Determine the storage size for the size. */
+                    const auto size_type = buffer_u8[-1] & EncodedSizeMask<u8>;
+                    if (size_type == EncodedSize1<u8>) {
+                        return DeleteBufferImpl<u8>(buffer);
+                    } else if (size_type == EncodedSize2<u8>) {
+                        return DeleteBufferImpl<u16>(buffer);
+                    } else if (size_type == EncodedSize4<u8>) {
+                        return DeleteBufferImpl<u32>(buffer);
+                    } else /* if (size_type == EncodedSize8<u8>) */ {
+                        return DeleteBufferImpl<u64>(buffer);
+                    }
+                }
+            private:
+                BufferEntryType m_buffer[1];
+            private:
+                ALWAYS_INLINE BufferWithInlineSize() noexcept { /* ... */ }
+            public:
+                ALWAYS_INLINE ~BufferWithInlineSize() noexcept { /* ... */ }
+            public:
+                ALWAYS_INLINE operator BufferEntryType *() noexcept {
+                    return m_buffer;
+                }
+
+                ALWAYS_INLINE operator const BufferEntryType *() const noexcept {
+                    return m_buffer;
+                }
+            public:
+                static ALWAYS_INLINE std::unique_ptr<BufferWithInlineSize> Make(size_t size) noexcept {
+                    /* Create based on overhead size. */
+                    if (!(size & TestSize1Mask)) {
+                        return MakeBuffer<u8, EncodedSize1<u8>>(size);
+                    } else if (!(size & TestSize2Mask)) {
+                        return MakeBuffer<u16, EncodedSize2<u16>>(size);
+                    } else if (!(size & TestSize4Mask)) {
+                        return MakeBuffer<u32, EncodedSize4<u32>>(size);
+                    } else /* if (!(size & TestSize8Mask)) */ {
+                        /* Check pre-condition. */
+                        AMS_ASSERT(!(size & TestSize8Mask));
+                        return MakeBuffer<u64, EncodedSize8<u64>>(size);
+                    }
+                }
+            public:
+                static ALWAYS_INLINE void *operator new(size_t) noexcept { AMS_ABORT(AMS_CURRENT_FUNCTION_NAME); }
+
+                static ALWAYS_INLINE void *operator new(size_t size, Newable *placement) noexcept { AMS_ABORT(AMS_CURRENT_FUNCTION_NAME); }
+
+                static ALWAYS_INLINE void operator delete(void *ptr, size_t) noexcept {
+                    /* Delete the buffer. */
+                    DeleteBuffer(reinterpret_cast<BufferWithInlineSize *>(ptr)->m_buffer);
+                }
+
+                static void *operator new[](size_t size) noexcept = delete;
+                static void operator delete[](void *ptr, size_t size) noexcept = delete;
+        };
+        #endif
+
         template<typename T>
-        std::unique_ptr<T, Deleter> MakeUnique() {
+        auto MakeUnique() {
-            static_assert(util::is_pod<T>::value);
+            /* Check that we're not using MakeUnique unnecessarily. */
+            static_assert(!std::derived_from<T, ::ams::fs::impl::Newable>);
+
             return std::unique_ptr<T, Deleter>(static_cast<T *>(::ams::fs::impl::Allocate(sizeof(T))), Deleter(sizeof(T)));
         }
 
         template<typename ArrayT>
-        std::unique_ptr<ArrayT, Deleter> MakeUnique(size_t size) {
+        auto MakeUnique(size_t size) {
             using T = typename std::remove_extent<ArrayT>::type;
 
             static_assert(util::is_pod<ArrayT>::value);
             static_assert(std::is_array<ArrayT>::value);
 
+            /* Check that we're not using MakeUnique unnecessarily. */
+            static_assert(!std::derived_from<T, ::ams::fs::impl::Newable>);
+
+            using ReturnType = std::unique_ptr<ArrayT, Deleter>;
+
             const size_t alloc_size = sizeof(T) * size;
-            return std::unique_ptr<ArrayT, Deleter>(static_cast<T *>(::ams::fs::impl::Allocate(alloc_size)), Deleter(alloc_size));
+            return ReturnType(static_cast<T *>(::ams::fs::impl::Allocate(alloc_size)), Deleter(alloc_size));
+        }
+
+        template<typename T>
+        auto MakeUniqueBuffer(size_t size) {
+            #if defined(AMS_FS_IMPL_MAKE_UNIQUE_BUFFER_WITH_INLINE_SIZE)
+            return BufferWithInlineSize<T>::Make(size);
+            #else
+            return ::ams::fs::impl::MakeUnique<T[]>(size);
+            #endif
         }
 
     }

libraries/libstratosphere/include/stratosphere/fs/fs_path.hpp

@@ -33,20 +33,30 @@ namespace ams::fs {
         private:
             friend class DirectoryPathParser;
         private:
-            using WriteBuffer = std::unique_ptr<char[], ::ams::fs::impl::Deleter>;
+            using WriteBuffer = decltype(::ams::fs::impl::MakeUniqueBuffer<char>(0));
+
+            template<std::same_as<WriteBuffer> T>
+            static ALWAYS_INLINE char *GetBuffer(T &write_buffer) {
+                if constexpr (std::same_as<T, decltype(::ams::fs::impl::MakeUnique<char[]>(0))>) {
+                    return write_buffer.get();
+                } else {
+                    return static_cast<char *>(*write_buffer);
+                }
+            }
+
+            static ALWAYS_INLINE WriteBuffer MakeWriteBuffer(size_t size) {
+                return ::ams::fs::impl::MakeUniqueBuffer<char>(size);
+            }
         private:
             const char *m_str;
             util::TypedStorage<WriteBuffer> m_write_buffer;
-            size_t m_write_buffer_length;
+            size_t m_write_buffer_length_and_is_normalized;
-            bool m_is_normalized;
         public:
-            Path() : m_str(EmptyPath), m_write_buffer_length(0), m_is_normalized(false) {
+            Path() : m_str(EmptyPath), m_write_buffer_length_and_is_normalized(0) {
                 util::ConstructAt(m_write_buffer, nullptr);
             }
 
-            constexpr Path(const char *s, util::ConstantInitializeTag) : m_str(s), m_write_buffer(), m_write_buffer_length(0), m_is_normalized(true) {
+            constexpr Path(const char *s, util::ConstantInitializeTag) : m_str(s), m_write_buffer(), m_write_buffer_length_and_is_normalized(1) { }
-                /* ... */
-            }
 
             constexpr ~Path() {
                 if (!std::is_constant_evaluated()) {
@@ -59,8 +69,8 @@ namespace ams::fs {
                 AMS_ASSERT(util::GetReference(m_write_buffer) != nullptr);
 
                 /* Reset. */
-                m_str                 = EmptyPath;
+                m_str = EmptyPath;
-                m_write_buffer_length = 0;
+                this->SetWriteBufferLength(0);
 
                 /* Return our write buffer. */
                 return std::move(util::GetReference(m_write_buffer));
@@ -68,7 +78,7 @@ namespace ams::fs {
 
             constexpr Result SetShallowBuffer(const char *buffer) {
                 /* Check pre-conditions. */
-                AMS_ASSERT(m_write_buffer_length == 0);
+                AMS_ASSERT(this->GetWriteBufferLength() == 0);
 
                 /* Check the buffer is valid. */
                 R_UNLESS(buffer != nullptr, fs::ResultNullptrArgument());
@@ -77,14 +87,14 @@ namespace ams::fs {
                 this->SetReadOnlyBuffer(buffer);
 
                 /* Note that we're normalized. */
-                m_is_normalized = true;
+                this->SetNormalized();
 
                 R_SUCCEED();
             }
 
             const char *GetString() const {
                 /* Check pre-conditions. */
-                AMS_ASSERT(m_is_normalized);
+                AMS_ASSERT(this->IsNormalized());
 
                 return m_str;
             }
@@ -103,18 +113,19 @@ namespace ams::fs {
 
             Result Initialize(const Path &rhs) {
                 /* Check the other path is normalized. */
-                R_UNLESS(rhs.m_is_normalized, fs::ResultNotNormalized());
+                const bool normalized = rhs.IsNormalized();
+                R_UNLESS(normalized, fs::ResultNotNormalized());
 
                 /* Allocate buffer for our path. */
                 const auto len = rhs.GetLength();
                 R_TRY(this->Preallocate(len + 1));
 
                 /* Copy the path. */
-                const size_t copied = util::Strlcpy<char>(util::GetReference(m_write_buffer).get(), rhs.GetString(), len + 1);
+                const size_t copied = util::Strlcpy<char>(GetBuffer(util::GetReference(m_write_buffer)), rhs.GetString(), len + 1);
                 R_UNLESS(copied == len, fs::ResultUnexpectedInPathA());
 
                 /* Set normalized. */
-                m_is_normalized = rhs.m_is_normalized;
+                this->SetNormalized();
                 R_SUCCEED();
             }
 
@@ -126,7 +137,7 @@ namespace ams::fs {
                 R_TRY(this->InitializeImpl(path, len));
 
                 /* Set not normalized. */
-                m_is_normalized = false;
+                this->SetNotNormalized();
 
                 R_SUCCEED();
             }
@@ -154,7 +165,7 @@ namespace ams::fs {
                 R_TRY(this->Preallocate(len + 1));
 
                 /* Format our path into our new buffer. */
-                const auto real_len = util::VSNPrintf(util::GetReference(m_write_buffer).get(), m_write_buffer_length, fmt, vl);
+                const auto real_len = util::VSNPrintf(GetBuffer(util::GetReference(m_write_buffer)), this->GetWriteBufferLength(), fmt, vl);
                 AMS_ASSERT(real_len == len);
                 AMS_UNUSED(real_len);
 
@@ -162,7 +173,7 @@ namespace ams::fs {
                 va_end(vl);
 
                 /* Set not normalized. */
-                m_is_normalized = false;
+                this->SetNotNormalized();
 
                 R_SUCCEED();
             }
@@ -175,12 +186,12 @@ namespace ams::fs {
                 R_TRY(this->InitializeImpl(path, std::strlen(path)));
 
                 /* Replace slashes as desired. */
-                if (m_write_buffer_length > 1) {
+                if (const auto write_buffer_length = this->GetWriteBufferLength(); write_buffer_length > 1) {
-                    fs::Replace(this->GetWriteBuffer(), m_write_buffer_length - 1, '\\', '/');
+                    fs::Replace(this->GetWriteBuffer(), write_buffer_length - 1, '\\', '/');
                 }
 
                 /* Set not normalized. */
-                m_is_normalized = false;
+                this->SetNotNormalized();
 
                 R_SUCCEED();
             }
@@ -193,7 +204,7 @@ namespace ams::fs {
                 R_TRY(this->InitializeImpl(path, std::strlen(path)));
 
                 /* Replace slashes as desired. */
-                if (m_write_buffer_length > 1) {
+                if (this->GetWriteBufferLength() > 1) {
                     if (auto *p = this->GetWriteBuffer(); p[0] == '/' && p[1] == '/') {
                         p[0] = '\\';
                         p[1] = '\\';
@@ -201,7 +212,7 @@ namespace ams::fs {
                 }
 
                 /* Set not normalized. */
-                m_is_normalized = false;
+                this->SetNotNormalized();
 
                 R_SUCCEED();
             }
@@ -214,7 +225,7 @@ namespace ams::fs {
                 R_TRY(this->InitializeImpl(path, std::strlen(path)));
 
                 /* Set not normalized. */
-                m_is_normalized = false;
+                this->SetNotNormalized();
 
                 /* Replace unc as desired. */
                 if (m_str[0]) {
@@ -251,7 +262,7 @@ namespace ams::fs {
                 R_TRY(this->InitializeImpl(path, size));
 
                 /* Set not normalized. */
-                m_is_normalized = false;
+                this->SetNotNormalized();
 
                 /* Perform normalization. */
                 fs::PathFlags path_flags;
@@ -263,16 +274,17 @@ namespace ams::fs {
                     /* NOTE: In this case, Nintendo checks is normalized, then sets is normalized, then returns success. */
                     /* This seems like a bug. */
                     size_t dummy;
-                    R_TRY(PathFormatter::IsNormalized(std::addressof(m_is_normalized), std::addressof(dummy), m_str));
+                    bool normalized;
+                    R_TRY(PathFormatter::IsNormalized(std::addressof(normalized), std::addressof(dummy), m_str));
 
-                    m_is_normalized = true;
+                    this->SetNormalized();
                     R_SUCCEED();
                 }
 
                 /* Normalize. */
                 R_TRY(this->Normalize(path_flags));
 
-                m_is_normalized = true;
+                this->SetNormalized();
                 R_SUCCEED();
             }
 
@@ -288,7 +300,7 @@ namespace ams::fs {
                 this->ClearBuffer();
 
                 /* Set normalized. */
-                m_is_normalized = true;
+                this->SetNormalized();
 
                 R_SUCCEED();
             }
@@ -335,7 +347,7 @@ namespace ams::fs {
                 /* Get our write buffer. */
                 auto *dst = this->GetWriteBuffer();
                 if (old_write_buffer != nullptr && cur_len > 0) {
-                    util::Strlcpy<char>(dst, old_write_buffer.get(), cur_len + 1);
+                    util::Strlcpy<char>(dst, static_cast<char *>(*old_write_buffer), cur_len + 1);
                 }
 
                 /* Add separator. */
@@ -379,7 +391,7 @@ namespace ams::fs {
                 if (util::GetReference(m_write_buffer) == nullptr) {
                     if (const auto len = std::strlen(m_str); len > 0) {
                         R_TRY(this->Preallocate(len));
-                        util::Strlcpy<char>(util::GetReference(m_write_buffer).get(), m_str, len + 1);
+                        util::Strlcpy<char>(GetBuffer(util::GetReference(m_write_buffer)), m_str, len + 1);
                     }
                 }
 
@@ -414,7 +426,7 @@ namespace ams::fs {
 
             Result Normalize(const PathFlags &flags) {
                 /* If we're already normalized, nothing to do. */
-                R_SUCCEED_IF(m_is_normalized);
+                R_SUCCEED_IF(this->IsNormalized());
 
                 /* Check if we're normalized. */
                 bool normalized;
@@ -424,7 +436,7 @@ namespace ams::fs {
                 /* If we're not normalized, normalize. */
                 if (!normalized) {
                     /* Determine necessary buffer length. */
-                    auto len = m_write_buffer_length;
+                    auto len = this->GetWriteBufferLength();
                     if (flags.IsRelativePathAllowed() && fs::IsPathRelative(m_str)) {
                         len += 2;
                     }
@@ -434,24 +446,24 @@ namespace ams::fs {
 
                     /* Allocate a new buffer. */
                     const size_t size = util::AlignUp(len, WriteBufferAlignmentLength);
-                    auto buf = fs::impl::MakeUnique<char[]>(size);
+                    auto buf = MakeWriteBuffer(size);
                     R_UNLESS(buf != nullptr, fs::ResultAllocationMemoryFailedMakeUnique());
 
                     /* Normalize into it. */
-                    R_TRY(PathFormatter::Normalize(buf.get(), size, util::GetReference(m_write_buffer).get(), m_write_buffer_length, flags));
+                    R_TRY(PathFormatter::Normalize(*buf, size, GetBuffer(util::GetReference(m_write_buffer)), this->GetWriteBufferLength(), flags));
 
                     /* Set the normalized buffer as our buffer. */
                     this->SetModifiableBuffer(std::move(buf), size);
                 }
 
                 /* Set normalized. */
-                m_is_normalized = true;
+                this->SetNormalized();
                 R_SUCCEED();
             }
         private:
             void ClearBuffer() {
                 util::GetReference(m_write_buffer).reset();
-                m_write_buffer_length = 0;
+                this->SetWriteBufferLength(0);
                 m_str = EmptyPath;
             }
 
@@ -463,24 +475,24 @@ namespace ams::fs {
 
                 /* Set write buffer. */
                 util::GetReference(m_write_buffer) = std::move(buffer);
-                m_write_buffer_length              = size;
+                this->SetWriteBufferLength(size);
-                m_str                              = util::GetReference(m_write_buffer).get();
+                m_str                              = GetBuffer(util::GetReference(m_write_buffer));
             }
 
             constexpr void SetReadOnlyBuffer(const char *buffer) {
                 m_str = buffer;
                 if (!std::is_constant_evaluated()) {
                     util::GetReference(m_write_buffer) = nullptr;
-                    m_write_buffer_length              = 0;
+                    this->SetWriteBufferLength(0);
                 }
             }
 
             Result Preallocate(size_t length) {
                 /* Allocate additional space, if needed. */
-                if (length > m_write_buffer_length) {
+                if (length > this->GetWriteBufferLength()) {
                     /* Allocate buffer. */
                     const size_t size = util::AlignUp(length, WriteBufferAlignmentLength);
-                    auto buf = fs::impl::MakeUnique<char[]>(size);
+                    auto buf = MakeWriteBuffer(size);
                     R_UNLESS(buf != nullptr, fs::ResultAllocationMemoryFailedMakeUnique());
 
                     /* Set write buffer. */
@@ -508,11 +520,27 @@ namespace ams::fs {
 
             char *GetWriteBuffer() {
                 AMS_ASSERT(util::GetReference(m_write_buffer) != nullptr);
-                return util::GetReference(m_write_buffer).get();
+                return GetBuffer(util::GetReference(m_write_buffer));
             }
 
-            size_t GetWriteBufferLength() const {
+            constexpr ALWAYS_INLINE size_t GetWriteBufferLength() const {
-                return m_write_buffer_length;
+                return m_write_buffer_length_and_is_normalized >> 1;
+            }
+
+            constexpr ALWAYS_INLINE void SetWriteBufferLength(size_t size) {
+                m_write_buffer_length_and_is_normalized = (m_write_buffer_length_and_is_normalized & 1) | (size << 1);
+            }
+
+            constexpr ALWAYS_INLINE bool IsNormalized() const {
+                return static_cast<bool>(m_write_buffer_length_and_is_normalized & 1);
+            }
+
+            constexpr ALWAYS_INLINE void SetNormalized() {
+                m_write_buffer_length_and_is_normalized |= static_cast<size_t>(1);
+            }
+
+            constexpr ALWAYS_INLINE void SetNotNormalized() {
+                m_write_buffer_length_and_is_normalized &= ~static_cast<size_t>(1);
             }
         public:
             ALWAYS_INLINE bool operator==(const fs::Path &rhs) const { return std::strcmp(this->GetString(), rhs.GetString()) == 0; }