DPL: revamp / remove Endian.h

C++20 (and even more so 23) has understanding of endianess.
No need to have a special wrapper include anymore.

Author: ktf

Framework/AnalysisSupport/src/TTreePlugin.cxx

@@ -12,7 +12,7 @@
 #include "Framework/RootArrowFilesystem.h"
 #include "Framework/Plugins.h"
 #include "Framework/Signpost.h"
-#include "Framework/Endian.h"
+#include <bit>
 #include <TBufferFile.h>
 #include <TBufferIO.h>
 #include <arrow/buffer.h>
@@ -187,6 +187,32 @@ arrow::Result<std::shared_ptr<arrow::Buffer>> TTreeDeferredReadOutputStream::Fin
 
 arrow::Result<int64_t> TTreeDeferredReadOutputStream::Tell() const { return position_; }
 
+static void bigEndianCopy(uint8_t* dest, char* src, int count, size_t typeSize) noexcept
+{
+  if constexpr (std::endian::native == std::endian::big) {
+    std::memcpy(dest, src, count * typeSize);
+    return;
+  }
+  switch (typeSize) {
+    case 2:
+      for (int i = 0; i < count; ++i) {
+        reinterpret_cast<uint16_t*>(dest)[i] = __builtin_bswap16(reinterpret_cast<uint16_t*>(src)[i]);
+      }
+      return;
+    case 4:
+      for (int i = 0; i < count; ++i) {
+        reinterpret_cast<uint32_t*>(dest)[i] = __builtin_bswap32(reinterpret_cast<uint32_t*>(src)[i]);
+      }
+      return;
+    case 8:
+      for (int i = 0; i < count; ++i) {
+        reinterpret_cast<uint64_t*>(dest)[i] = __builtin_bswap64(reinterpret_cast<uint64_t*>(src)[i]);
+      }
+      return;
+  }
+  std::memcpy(dest, src, count * typeSize);
+}
+
 auto readValues = [](uint8_t* target, ReadOps& op, TBufferFile& rootBuffer) {
   int readEntries = 0;
   rootBuffer.Reset();
@@ -197,7 +223,7 @@ auto readValues = [](uint8_t* target, ReadOps& op, TBufferFile& rootBuffer) {
     }
     int size = readLast * op.listSize;
     readEntries += readLast;
-    swapCopy(target, rootBuffer.GetCurrent(), size, op.typeSize);
+    bigEndianCopy(target, rootBuffer.GetCurrent(), size, op.typeSize);
     target += (ptrdiff_t)(size * op.typeSize);
   }
 };
@@ -230,7 +256,7 @@ auto readVLAValues = [](uint8_t* target, ReadOps& op, ReadOps const& offsetOp, T
     auto readLast = op.branch->GetBulkRead().GetEntriesSerialized(readEntries, rootBuffer);
     int size = offsets[readEntries + readLast] - offsets[readEntries];
     readEntries += readLast;
-    swapCopy(target, rootBuffer.GetCurrent(), size, op.typeSize);
+    bigEndianCopy(target, rootBuffer.GetCurrent(), size, op.typeSize);
     target += (ptrdiff_t)(size * op.typeSize);
   }
 };
@@ -581,7 +607,8 @@ auto readOffsets = [](ReadOps& op, TBufferFile& rootBuffer) {
     readEntries += readLast;
     for (auto i = 0; i < readLast; ++i) {
       offsets[count++] = (int)offset;
-      offset += swap32_(reinterpret_cast<uint32_t*>(rootBuffer.GetCurrent())[i]);
+      uint32_t raw = reinterpret_cast<uint32_t*>(rootBuffer.GetCurrent())[i];
+      offset += (std::endian::native == std::endian::little) ? __builtin_bswap32(raw) : raw;
     }
   }
   offsets[count] = (int)offset;

Framework/AnalysisSupport/src/TableTreeHelpers.cxx

@@ -10,7 +10,6 @@
 // or submit itself to any jurisdiction.
 #include "Framework/TableTreeHelpers.h"
 #include "Framework/Logger.h"
-#include "Framework/Endian.h"
 #include "Framework/Signpost.h"
 
 #include <arrow/dataset/file_base.h>

Framework/Core/src/FragmentToBatch.cxx

@@ -10,7 +10,6 @@
 // or submit itself to any jurisdiction.
 #include "Framework/FragmentToBatch.h"
 #include "Framework/Logger.h"
-#include "Framework/Endian.h"
 #include "Framework/Signpost.h"
 
 #include <arrow/dataset/file_base.h>

Framework/Core/src/HTTPParser.cxx

@@ -90,7 +90,7 @@ void encode_websocket_frames(std::vector<uv_buf_t>& outputs, char const* src, si
     WebSocketFrameHuge* header = (WebSocketFrameHuge*)buffer;
     memset(buffer, 0, headerSize);
     header->len = 127;
-    header->len64 = htonll(size);
+    header->len64 = (std::endian::native == std::endian::little) ? __builtin_bswap64(size) : size;
     outputs.push_back(uv_buf_init(buffer, size + maskSize + headerSize));
   }
   size_t fullHeaderSize = maskSize + headerSize;
@@ -165,7 +165,7 @@ void decode_websocket(char* start, size_t size, WebSocketHandler& handler)
       headerSize = 2 + 2 + (header->mask ? 4 : 0);
     } else if (header->len == 127) {
       WebSocketFrameHuge* headerSmall = (WebSocketFrameHuge*)cur;
-      payloadSize = ntohll(headerSmall->len64);
+      payloadSize = (std::endian::native == std::endian::little) ? __builtin_bswap64(headerSmall->len64) : headerSmall->len64;
       headerSize = 2 + 8 + (header->mask ? 4 : 0);
     }
     size_t availableSize = size - (cur - start);

Framework/Core/src/HTTPParser.h

@@ -12,7 +12,8 @@
 #ifndef O2_FRAMEWORK_HTTPPARSER_H_
 #define O2_FRAMEWORK_HTTPPARSER_H_
 
-#include "Framework/Endian.h"
+#include <bit>
+#include <cstdint>
 #include <fmt/format.h>
 #include <uv.h>
 #include <string>
@@ -22,74 +23,91 @@
 namespace o2::framework
 {
 
-struct __attribute__((__packed__)) WebSocketFrameTiny {
-#if O2_HOST_BYTE_ORDER == O2_LITTLE_ENDIAN
+template <std::endian E>
+struct __attribute__((__packed__)) WebSocketFrameTiny;
+
+template <>
+struct __attribute__((__packed__)) WebSocketFrameTiny<std::endian::little> {
   unsigned char opcode : 4;
   unsigned char rsv3 : 1;
   unsigned char rsv2 : 1;
   unsigned char rsv1 : 1;
   unsigned char fin : 1;
   unsigned char len : 7;
   unsigned char mask : 1;
-#elif O2_HOST_BYTE_ORDER == O2_BIG_ENDIAN
+};
+
+template <>
+struct __attribute__((__packed__)) WebSocketFrameTiny<std::endian::big> {
   unsigned char fin : 1;
   unsigned char rsv1 : 1;
   unsigned char rsv2 : 1;
   unsigned char rsv3 : 1;
   unsigned char opcode : 4;
   unsigned char mask : 1;
   unsigned char len : 7;
-#else
-#error Uknown endiannes
-#endif
 };
 
-struct __attribute__((__packed__)) WebSocketFrameShort {
-#if O2_HOST_BYTE_ORDER == O2_LITTLE_ENDIAN
+using WebSocketFrameTiny = WebSocketFrameTiny<std::endian::native>;
+
+template <std::endian E>
+struct __attribute__((__packed__)) WebSocketFrameShort;
+
+template <>
+struct __attribute__((__packed__)) WebSocketFrameShort<std::endian::little> {
   unsigned char opcode : 4;
   unsigned char rsv3 : 1;
   unsigned char rsv2 : 1;
   unsigned char rsv1 : 1;
   unsigned char fin : 1;
   unsigned char len : 7;
   unsigned char mask : 1;
-#elif O2_HOST_BYTE_ORDER == O2_BIG_ENDIAN
+  uint16_t len16;
+};
+
+template <>
+struct __attribute__((__packed__)) WebSocketFrameShort<std::endian::big> {
   unsigned char fin : 1;
   unsigned char rsv1 : 1;
   unsigned char rsv2 : 1;
   unsigned char rsv3 : 1;
   unsigned char opcode : 4;
   unsigned char mask : 1;
   unsigned char len : 7;
-#else
-#error Uknown endiannes
-#endif
   uint16_t len16;
 };
 
-struct __attribute__((__packed__)) WebSocketFrameHuge {
-#if O2_HOST_BYTE_ORDER == O2_LITTLE_ENDIAN
+using WebSocketFrameShort = WebSocketFrameShort<std::endian::native>;
+
+template <std::endian E>
+struct __attribute__((__packed__)) WebSocketFrameHuge;
+
+template <>
+struct __attribute__((__packed__)) WebSocketFrameHuge<std::endian::little> {
   unsigned char opcode : 4;
   unsigned char rsv3 : 1;
   unsigned char rsv2 : 1;
   unsigned char rsv1 : 1;
   unsigned char fin : 1;
   unsigned char len : 7;
   unsigned char mask : 1;
-#elif O2_HOST_BYTE_ORDER == O2_BIG_ENDIAN
+  uint64_t len64;
+};
+
+template <>
+struct __attribute__((__packed__)) WebSocketFrameHuge<std::endian::big> {
   unsigned char fin : 1;
   unsigned char rsv1 : 1;
   unsigned char rsv2 : 1;
   unsigned char rsv3 : 1;
   unsigned char opcode : 4;
   unsigned char mask : 1;
   unsigned char len : 7;
-#else
-#error Uknown endiannes
-#endif
   uint64_t len64;
 };
 
+using WebSocketFrameHuge = WebSocketFrameHuge<std::endian::native>;
+
 enum struct WebSocketFrameKind {
   Tiny,
   Short,
@@ -138,9 +156,9 @@ struct WebSocketHandler {
   virtual ~WebSocketHandler() = default;
 
   /// Invoked when all the headers are received.
-  virtual void headers(std::map<std::string, std::string> const& headers){};
+  virtual void headers(std::map<std::string, std::string> const& headers) {};
   /// FIXME: not implemented
-  virtual void beginFragmentation(){};
+  virtual void beginFragmentation() {};
   /// Invoked when a frame it's parsed. Notice you do not own the data and you must
   /// not free the memory.
   virtual void frame(char const* frame, size_t s) {}
@@ -205,18 +223,18 @@ struct HTTPParser {
   std::string remaining;
   std::string error;
   std::vector<HTTPState> states;
-  virtual void method(std::string_view const& s){};
-  virtual void target(std::string_view const& s){};
-  virtual void version(std::string_view const& s){};
-  virtual void header(std::string_view const& k, std::string_view const& v){};
-  virtual void endHeaders(){};
+  virtual void method(std::string_view const& s) {};
+  virtual void target(std::string_view const& s) {};
+  virtual void version(std::string_view const& s) {};
+  virtual void header(std::string_view const& k, std::string_view const& v) {};
+  virtual void endHeaders() {};
   /// Invoked whenever we are parsing data.
   /// In order to allow for xoring (as required by the websocket standard)
   /// in place, we pass it as a mutable pointer.
-  virtual void body(char* data, size_t s){};
-  virtual void replyVersion(std::string_view const& s){};
-  virtual void replyCode(std::string_view const& s){};
-  virtual void replyMessage(std::string_view const& s){};
+  virtual void body(char* data, size_t s) {};
+  virtual void replyVersion(std::string_view const& s) {};
+  virtual void replyCode(std::string_view const& s) {};
+  virtual void replyMessage(std::string_view const& s) {};
 };
 
 struct HTTPParserHelpers {