13 files changed, 78 insertions, 72 deletions

diff --git a/src/core/hle/kernel/hle_ipc.h b/src/core/hle/kernel/hle_ipc.h
index d87be72d6..e252b5f4b 100644
--- a/src/core/hle/kernel/hle_ipc.h
+++ b/src/core/hle/kernel/hle_ipc.h
@@ -199,7 +199,7 @@ public:
     ~HLERequestContext();
 
     /// Returns a pointer to the IPC command buffer for this request.
-    u32* CommandBuffer() {
+    [[nodiscard]] u32* CommandBuffer() {
         return cmd_buf.data();
     }
 
@@ -207,7 +207,7 @@ public:
      * Returns the session through which this request was made. This can be used as a map key to
      * access per-client data on services.
      */
-    Kernel::KServerSession* Session() {
+    [[nodiscard]] Kernel::KServerSession* Session() {
         return server_session;
     }
 
@@ -217,61 +217,61 @@ public:
     /// Writes data from this context back to the requesting process/thread.
     Result WriteToOutgoingCommandBuffer(KThread& requesting_thread);
 
-    u32_le GetHipcCommand() const {
+    [[nodiscard]] u32_le GetHipcCommand() const {
         return command;
     }
 
-    u32_le GetTipcCommand() const {
+    [[nodiscard]] u32_le GetTipcCommand() const {
         return static_cast<u32_le>(command_header->type.Value()) -
                static_cast<u32_le>(IPC::CommandType::TIPC_CommandRegion);
     }
 
-    u32_le GetCommand() const {
+    [[nodiscard]] u32_le GetCommand() const {
         return command_header->IsTipc() ? GetTipcCommand() : GetHipcCommand();
     }
 
-    bool IsTipc() const {
+    [[nodiscard]] bool IsTipc() const {
         return command_header->IsTipc();
     }
 
-    IPC::CommandType GetCommandType() const {
+    [[nodiscard]] IPC::CommandType GetCommandType() const {
         return command_header->type;
     }
 
-    u64 GetPID() const {
+    [[nodiscard]] u64 GetPID() const {
         return pid;
     }
 
-    u32 GetDataPayloadOffset() const {
+    [[nodiscard]] u32 GetDataPayloadOffset() const {
         return data_payload_offset;
     }
 
-    const std::vector<IPC::BufferDescriptorX>& BufferDescriptorX() const {
+    [[nodiscard]] const std::vector<IPC::BufferDescriptorX>& BufferDescriptorX() const {
         return buffer_x_desciptors;
     }
 
-    const std::vector<IPC::BufferDescriptorABW>& BufferDescriptorA() const {
+    [[nodiscard]] const std::vector<IPC::BufferDescriptorABW>& BufferDescriptorA() const {
         return buffer_a_desciptors;
     }
 
-    const std::vector<IPC::BufferDescriptorABW>& BufferDescriptorB() const {
+    [[nodiscard]] const std::vector<IPC::BufferDescriptorABW>& BufferDescriptorB() const {
         return buffer_b_desciptors;
     }
 
-    const std::vector<IPC::BufferDescriptorC>& BufferDescriptorC() const {
+    [[nodiscard]] const std::vector<IPC::BufferDescriptorC>& BufferDescriptorC() const {
         return buffer_c_desciptors;
     }
 
-    const IPC::DomainMessageHeader& GetDomainMessageHeader() const {
+    [[nodiscard]] const IPC::DomainMessageHeader& GetDomainMessageHeader() const {
         return domain_message_header.value();
     }
 
-    bool HasDomainMessageHeader() const {
+    [[nodiscard]] bool HasDomainMessageHeader() const {
         return domain_message_header.has_value();
     }
 
     /// Helper function to read a buffer using the appropriate buffer descriptor
-    std::vector<u8> ReadBuffer(std::size_t buffer_index = 0) const;
+    [[nodiscard]] std::vector<u8> ReadBuffer(std::size_t buffer_index = 0) const;
 
     /// Helper function to write a buffer using the appropriate buffer descriptor
     std::size_t WriteBuffer(const void* buffer, std::size_t size,
@@ -308,22 +308,34 @@ public:
     }
 
     /// Helper function to get the size of the input buffer
-    std::size_t GetReadBufferSize(std::size_t buffer_index = 0) const;
+    [[nodiscard]] std::size_t GetReadBufferSize(std::size_t buffer_index = 0) const;
 
     /// Helper function to get the size of the output buffer
-    std::size_t GetWriteBufferSize(std::size_t buffer_index = 0) const;
+    [[nodiscard]] std::size_t GetWriteBufferSize(std::size_t buffer_index = 0) const;
+
+    /// Helper function to derive the number of elements able to be contained in the read buffer
+    template <typename T>
+    [[nodiscard]] std::size_t GetReadBufferNumElements(std::size_t buffer_index = 0) const {
+        return GetReadBufferSize(buffer_index) / sizeof(T);
+    }
+
+    /// Helper function to derive the number of elements able to be contained in the write buffer
+    template <typename T>
+    [[nodiscard]] std::size_t GetWriteBufferNumElements(std::size_t buffer_index = 0) const {
+        return GetWriteBufferSize(buffer_index) / sizeof(T);
+    }
 
     /// Helper function to test whether the input buffer at buffer_index can be read
-    bool CanReadBuffer(std::size_t buffer_index = 0) const;
+    [[nodiscard]] bool CanReadBuffer(std::size_t buffer_index = 0) const;
 
     /// Helper function to test whether the output buffer at buffer_index can be written
-    bool CanWriteBuffer(std::size_t buffer_index = 0) const;
+    [[nodiscard]] bool CanWriteBuffer(std::size_t buffer_index = 0) const;
 
-    Handle GetCopyHandle(std::size_t index) const {
+    [[nodiscard]] Handle GetCopyHandle(std::size_t index) const {
         return incoming_copy_handles.at(index);
     }
 
-    Handle GetMoveHandle(std::size_t index) const {
+    [[nodiscard]] Handle GetMoveHandle(std::size_t index) const {
         return incoming_move_handles.at(index);
     }
 
@@ -348,13 +360,13 @@ public:
         manager = manager_;
     }
 
-    std::string Description() const;
+    [[nodiscard]] std::string Description() const;
 
-    KThread& GetThread() {
+    [[nodiscard]] KThread& GetThread() {
         return *thread;
     }
 
-    std::shared_ptr<SessionRequestManager> GetManager() const {
+    [[nodiscard]] std::shared_ptr<SessionRequestManager> GetManager() const {
         return manager.lock();
     }
 
diff --git a/src/core/hle/service/audio/audin_u.cpp b/src/core/hle/service/audio/audin_u.cpp
index 608925dfc..053e8f9dd 100644
--- a/src/core/hle/service/audio/audin_u.cpp
+++ b/src/core/hle/service/audio/audin_u.cpp
@@ -122,10 +122,10 @@ private:
     }
 
     void GetReleasedAudioInBuffer(Kernel::HLERequestContext& ctx) {
-        auto write_buffer_size = ctx.GetWriteBufferSize() / sizeof(u64);
-        std::vector<u64> released_buffers(write_buffer_size, 0);
+        const auto write_buffer_size = ctx.GetWriteBufferNumElements<u64>();
+        std::vector<u64> released_buffers(write_buffer_size);
 
-        auto count = impl->GetReleasedBuffers(released_buffers);
+        const auto count = impl->GetReleasedBuffers(released_buffers);
 
         [[maybe_unused]] std::string tags{};
         for (u32 i = 0; i < count; i++) {
@@ -228,7 +228,7 @@ void AudInU::ListAudioIns(Kernel::HLERequestContext& ctx) {
     LOG_DEBUG(Service_Audio, "called");
 
     const auto write_count =
-        static_cast<u32>(ctx.GetWriteBufferSize() / sizeof(AudioDevice::AudioDeviceName));
+        static_cast<u32>(ctx.GetWriteBufferNumElements<AudioDevice::AudioDeviceName>());
     std::vector<AudioDevice::AudioDeviceName> device_names{};
 
     u32 out_count{0};
@@ -248,7 +248,7 @@ void AudInU::ListAudioInsAutoFiltered(Kernel::HLERequestContext& ctx) {
     LOG_DEBUG(Service_Audio, "called");
 
     const auto write_count =
-        static_cast<u32>(ctx.GetWriteBufferSize() / sizeof(AudioDevice::AudioDeviceName));
+        static_cast<u32>(ctx.GetWriteBufferNumElements<AudioDevice::AudioDeviceName>());
     std::vector<AudioDevice::AudioDeviceName> device_names{};
 
     u32 out_count{0};
diff --git a/src/core/hle/service/audio/audout_u.cpp b/src/core/hle/service/audio/audout_u.cpp
index 122290c6a..29751f075 100644
--- a/src/core/hle/service/audio/audout_u.cpp
+++ b/src/core/hle/service/audio/audout_u.cpp
@@ -129,16 +129,16 @@ private:
     }
 
     void GetReleasedAudioOutBuffers(Kernel::HLERequestContext& ctx) {
-        auto write_buffer_size = ctx.GetWriteBufferSize() / sizeof(u64);
-        std::vector<u64> released_buffers(write_buffer_size, 0);
+        const auto write_buffer_size = ctx.GetWriteBufferNumElements<u64>();
+        std::vector<u64> released_buffers(write_buffer_size);
 
-        auto count = impl->GetReleasedBuffers(released_buffers);
+        const auto count = impl->GetReleasedBuffers(released_buffers);
 
         [[maybe_unused]] std::string tags{};
         for (u32 i = 0; i < count; i++) {
             tags += fmt::format("{:08X}, ", released_buffers[i]);
         }
-        [[maybe_unused]] auto sessionid{impl->GetSystem().GetSessionId()};
+        [[maybe_unused]] const auto sessionid{impl->GetSystem().GetSessionId()};
         LOG_TRACE(Service_Audio, "called. Session {} released {} buffers: {}", sessionid, count,
                   tags);
 
@@ -244,7 +244,7 @@ void AudOutU::ListAudioOuts(Kernel::HLERequestContext& ctx) {
     std::scoped_lock l{impl->mutex};
 
     const auto write_count =
-        static_cast<u32>(ctx.GetWriteBufferSize() / sizeof(AudioDevice::AudioDeviceName));
+        static_cast<u32>(ctx.GetWriteBufferNumElements<AudioDevice::AudioDeviceName>());
     std::vector<AudioDevice::AudioDeviceName> device_names{};
     if (write_count > 0) {
         device_names.emplace_back("DeviceOut");
diff --git a/src/core/hle/service/audio/audren_u.cpp b/src/core/hle/service/audio/audren_u.cpp
index 13423dca6..034ee273f 100644
--- a/src/core/hle/service/audio/audren_u.cpp
+++ b/src/core/hle/service/audio/audren_u.cpp
@@ -274,7 +274,7 @@ public:
 
 private:
     void ListAudioDeviceName(Kernel::HLERequestContext& ctx) {
-        const size_t in_count = ctx.GetWriteBufferSize() / sizeof(AudioDevice::AudioDeviceName);
+        const size_t in_count = ctx.GetWriteBufferNumElements<AudioDevice::AudioDeviceName>();
 
         std::vector<AudioDevice::AudioDeviceName> out_names{};
 
@@ -335,7 +335,7 @@ private:
     }
 
     void GetActiveAudioDeviceName(Kernel::HLERequestContext& ctx) {
-        const auto write_size = ctx.GetWriteBufferSize() / sizeof(char);
+        const auto write_size = ctx.GetWriteBufferSize();
         std::string out_name{"AudioTvOutput"};
 
         LOG_DEBUG(Service_Audio, "(STUBBED) called. Name={}", out_name);
@@ -387,7 +387,7 @@ private:
     }
 
     void ListAudioOutputDeviceName(Kernel::HLERequestContext& ctx) {
-        const size_t in_count = ctx.GetWriteBufferSize() / sizeof(AudioDevice::AudioDeviceName);
+        const size_t in_count = ctx.GetWriteBufferNumElements<AudioDevice::AudioDeviceName>();
 
         std::vector<AudioDevice::AudioDeviceName> out_names{};
 
diff --git a/src/core/hle/service/audio/hwopus.cpp b/src/core/hle/service/audio/hwopus.cpp
index 8bafc3a98..825fb8bcc 100644
--- a/src/core/hle/service/audio/hwopus.cpp
+++ b/src/core/hle/service/audio/hwopus.cpp
@@ -68,7 +68,7 @@ private:
                                  ExtraBehavior extra_behavior) {
         u32 consumed = 0;
         u32 sample_count = 0;
-        std::vector<opus_int16> samples(ctx.GetWriteBufferSize() / sizeof(opus_int16));
+        std::vector<opus_int16> samples(ctx.GetWriteBufferNumElements<opus_int16>());
 
         if (extra_behavior == ExtraBehavior::ResetContext) {
             ResetDecoderContext();
diff --git a/src/core/hle/service/bcat/bcat_module.cpp b/src/core/hle/service/bcat/bcat_module.cpp
index bc08ac487..cbe690a5d 100644
--- a/src/core/hle/service/bcat/bcat_module.cpp
+++ b/src/core/hle/service/bcat/bcat_module.cpp
@@ -443,7 +443,7 @@ private:
     }
 
     void Read(Kernel::HLERequestContext& ctx) {
-        auto write_size = ctx.GetWriteBufferSize() / sizeof(DeliveryCacheDirectoryEntry);
+        auto write_size = ctx.GetWriteBufferNumElements<DeliveryCacheDirectoryEntry>();
 
         LOG_DEBUG(Service_BCAT, "called, write_size={:016X}", write_size);
 
@@ -533,7 +533,7 @@ private:
     }
 
     void EnumerateDeliveryCacheDirectory(Kernel::HLERequestContext& ctx) {
-        auto size = ctx.GetWriteBufferSize() / sizeof(DirectoryName);
+        auto size = ctx.GetWriteBufferNumElements<DirectoryName>();
 
         LOG_DEBUG(Service_BCAT, "called, size={:016X}", size);
 
diff --git a/src/core/hle/service/es/es.cpp b/src/core/hle/service/es/es.cpp
index ff9b0427c..d183e5829 100644
--- a/src/core/hle/service/es/es.cpp
+++ b/src/core/hle/service/es/es.cpp
@@ -192,12 +192,10 @@ private:
     }
 
     void ListCommonTicketRightsIds(Kernel::HLERequestContext& ctx) {
-        u32 out_entries;
-        if (keys.GetCommonTickets().empty())
-            out_entries = 0;
-        else
-            out_entries = static_cast<u32>(ctx.GetWriteBufferSize() / sizeof(u128));
-
+        size_t out_entries = 0;
+        if (!keys.GetCommonTickets().empty()) {
+            out_entries = ctx.GetWriteBufferNumElements<u128>();
+        }
         LOG_DEBUG(Service_ETicket, "called, entries={:016X}", out_entries);
 
         keys.PopulateTickets();
@@ -206,20 +204,19 @@ private:
         std::transform(tickets.begin(), tickets.end(), std::back_inserter(ids),
                        [](const auto& pair) { return pair.first; });
 
-        out_entries = static_cast<u32>(std::min<std::size_t>(ids.size(), out_entries));
+        out_entries = std::min(ids.size(), out_entries);
         ctx.WriteBuffer(ids.data(), out_entries * sizeof(u128));
 
         IPC::ResponseBuilder rb{ctx, 3};
         rb.Push(ResultSuccess);
-        rb.Push<u32>(out_entries);
+        rb.Push<u32>(static_cast<u32>(out_entries));
     }
 
     void ListPersonalizedTicketRightsIds(Kernel::HLERequestContext& ctx) {
-        u32 out_entries;
-        if (keys.GetPersonalizedTickets().empty())
-            out_entries = 0;
-        else
-            out_entries = static_cast<u32>(ctx.GetWriteBufferSize() / sizeof(u128));
+        size_t out_entries = 0;
+        if (!keys.GetPersonalizedTickets().empty()) {
+            out_entries = ctx.GetWriteBufferNumElements<u128>();
+        }
 
         LOG_DEBUG(Service_ETicket, "called, entries={:016X}", out_entries);
 
@@ -229,12 +226,12 @@ private:
         std::transform(tickets.begin(), tickets.end(), std::back_inserter(ids),
                        [](const auto& pair) { return pair.first; });
 
-        out_entries = static_cast<u32>(std::min<std::size_t>(ids.size(), out_entries));
+        out_entries = std::min(ids.size(), out_entries);
         ctx.WriteBuffer(ids.data(), out_entries * sizeof(u128));
 
         IPC::ResponseBuilder rb{ctx, 3};
         rb.Push(ResultSuccess);
-        rb.Push<u32>(out_entries);
+        rb.Push<u32>(static_cast<u32>(out_entries));
     }
 
     void GetCommonTicketSize(Kernel::HLERequestContext& ctx) {
diff --git a/src/core/hle/service/filesystem/fsp_srv.cpp b/src/core/hle/service/filesystem/fsp_srv.cpp
index c08274ef9..fbb16a7da 100644
--- a/src/core/hle/service/filesystem/fsp_srv.cpp
+++ b/src/core/hle/service/filesystem/fsp_srv.cpp
@@ -277,7 +277,7 @@ private:
         LOG_DEBUG(Service_FS, "called.");
 
         // Calculate how many entries we can fit in the output buffer
-        const u64 count_entries = ctx.GetWriteBufferSize() / sizeof(FileSys::Entry);
+        const u64 count_entries = ctx.GetWriteBufferNumElements<FileSys::Entry>();
 
         // Cap at total number of entries.
         const u64 actual_entries = std::min(count_entries, entries.size() - next_entry_index);
@@ -543,7 +543,7 @@ public:
         LOG_DEBUG(Service_FS, "called");
 
         // Calculate how many entries we can fit in the output buffer
-        const u64 count_entries = ctx.GetWriteBufferSize() / sizeof(SaveDataInfo);
+        const u64 count_entries = ctx.GetWriteBufferNumElements<SaveDataInfo>();
 
         // Cap at total number of entries.
         const u64 actual_entries = std::min(count_entries, info.size() - next_entry_index);
diff --git a/src/core/hle/service/ldn/ldn.cpp b/src/core/hle/service/ldn/ldn.cpp
index 6df563136..c49c61cff 100644
--- a/src/core/hle/service/ldn/ldn.cpp
+++ b/src/core/hle/service/ldn/ldn.cpp
@@ -292,7 +292,7 @@ public:
 
     void GetNetworkInfoLatestUpdate(Kernel::HLERequestContext& ctx) {
         const std::size_t network_buffer_size = ctx.GetWriteBufferSize(0);
-        const std::size_t node_buffer_count = ctx.GetWriteBufferSize(1) / sizeof(NodeLatestUpdate);
+        const std::size_t node_buffer_count = ctx.GetWriteBufferNumElements<NodeLatestUpdate>(1);
 
         if (node_buffer_count == 0 || network_buffer_size != sizeof(NetworkInfo)) {
             LOG_ERROR(Service_LDN, "Invalid buffer, size = {}, count = {}", network_buffer_size,
@@ -333,7 +333,7 @@ public:
         const auto channel{rp.PopEnum<WifiChannel>()};
         const auto scan_filter{rp.PopRaw<ScanFilter>()};
 
-        const std::size_t network_info_size = ctx.GetWriteBufferSize() / sizeof(NetworkInfo);
+        const std::size_t network_info_size = ctx.GetWriteBufferNumElements<NetworkInfo>();
 
         if (network_info_size == 0) {
             LOG_ERROR(Service_LDN, "Invalid buffer size {}", network_info_size);
diff --git a/src/core/hle/service/nfc/nfc_user.cpp b/src/core/hle/service/nfc/nfc_user.cpp
index 0753333bf..ced2d560b 100644
--- a/src/core/hle/service/nfc/nfc_user.cpp
+++ b/src/core/hle/service/nfc/nfc_user.cpp
@@ -118,7 +118,7 @@ void IUser::ListDevices(Kernel::HLERequestContext& ctx) {
     }
 
     std::vector<u64> nfp_devices;
-    const std::size_t max_allowed_devices = ctx.GetWriteBufferSize() / sizeof(u64);
+    const std::size_t max_allowed_devices = ctx.GetWriteBufferNumElements<u64>();
 
     for (auto& device : devices) {
         if (nfp_devices.size() >= max_allowed_devices) {
diff --git a/src/core/hle/service/nfp/nfp_user.cpp b/src/core/hle/service/nfp/nfp_user.cpp
index 2fe3c0ea0..49816b4c7 100644
--- a/src/core/hle/service/nfp/nfp_user.cpp
+++ b/src/core/hle/service/nfp/nfp_user.cpp
@@ -104,9 +104,9 @@ void IUser::ListDevices(Kernel::HLERequestContext& ctx) {
     }
 
     std::vector<u64> nfp_devices;
-    const std::size_t max_allowed_devices = ctx.GetWriteBufferSize() / sizeof(u64);
+    const std::size_t max_allowed_devices = ctx.GetWriteBufferNumElements<u64>();
 
-    for (auto& device : devices) {
+    for (const auto& device : devices) {
         if (nfp_devices.size() >= max_allowed_devices) {
             continue;
         }
@@ -115,7 +115,7 @@ void IUser::ListDevices(Kernel::HLERequestContext& ctx) {
         }
     }
 
-    if (nfp_devices.size() == 0) {
+    if (nfp_devices.empty()) {
         IPC::ResponseBuilder rb{ctx, 2};
         rb.Push(DeviceNotFound);
         return;
diff --git a/src/core/hle/service/ns/iplatform_service_manager.cpp b/src/core/hle/service/ns/iplatform_service_manager.cpp
index fd047ff26..1fab2f0dd 100644
--- a/src/core/hle/service/ns/iplatform_service_manager.cpp
+++ b/src/core/hle/service/ns/iplatform_service_manager.cpp
@@ -279,13 +279,10 @@ void IPlatformServiceManager::GetSharedFontInOrderOfPriority(Kernel::HLERequestC
         font_sizes.push_back(region.size);
     }
 
-    // Resize buffers if game requests smaller size output.
-    font_codes.resize(
-        std::min<std::size_t>(font_codes.size(), ctx.GetWriteBufferSize(0) / sizeof(u32)));
-    font_offsets.resize(
-        std::min<std::size_t>(font_offsets.size(), ctx.GetWriteBufferSize(1) / sizeof(u32)));
-    font_sizes.resize(
-        std::min<std::size_t>(font_sizes.size(), ctx.GetWriteBufferSize(2) / sizeof(u32)));
+    // Resize buffers if game requests smaller size output
+    font_codes.resize(std::min(font_codes.size(), ctx.GetWriteBufferNumElements<u32>(0)));
+    font_offsets.resize(std::min(font_offsets.size(), ctx.GetWriteBufferNumElements<u32>(1)));
+    font_sizes.resize(std::min(font_sizes.size(), ctx.GetWriteBufferNumElements<u32>(2)));
 
     ctx.WriteBuffer(font_codes, 0);
     ctx.WriteBuffer(font_offsets, 1);
diff --git a/src/core/hle/service/set/set.cpp b/src/core/hle/service/set/set.cpp
index f761c2da4..4f1a8d6b7 100644
--- a/src/core/hle/service/set/set.cpp
+++ b/src/core/hle/service/set/set.cpp
@@ -83,7 +83,7 @@ void PushResponseLanguageCode(Kernel::HLERequestContext& ctx, std::size_t num_la
 }
 
 void GetAvailableLanguageCodesImpl(Kernel::HLERequestContext& ctx, std::size_t max_entries) {
-    const std::size_t requested_amount = ctx.GetWriteBufferSize() / sizeof(LanguageCode);
+    const std::size_t requested_amount = ctx.GetWriteBufferNumElements<LanguageCode>();
     const std::size_t max_amount = std::min(requested_amount, max_entries);
     const std::size_t copy_amount = std::min(available_language_codes.size(), max_amount);
     const std::size_t copy_size = copy_amount * sizeof(LanguageCode);