More on endianness

README.md

@@ -95,6 +95,10 @@ building the library or including the function definitions:
 #define BOOST_JSON_STACK_BUFFER_SIZE 1024
 #include <boost/json/src.hpp>
 ```
+### Endianness
+
+Boost.JSON uses [Boost.Endian](https://www.boost.org/doc/libs/release/libs/endian/doc/html/endian.html)
+in order to support both little endian and big endian platforms.
 
 ### Supported Compilers
 

doc/qbk/overview.qbk

@@ -120,6 +120,12 @@ building the library or including the function definitions:
 #include <boost/json/src.hpp>
 ```
 
+[heading Endianness]
+
+Boost.JSON uses
+[@https://www.boost.org/doc/libs/release/libs/endian/doc/html/endian.html
+Boost.Endian] in order to support both little endian and big endian platforms.
+
 [heading Supported Compilers]
 
 Boost.JSON has been tested with the following compilers:

include/boost/json/detail/sse2.hpp

@@ -136,7 +136,7 @@ count_valid<false>(
  uint8_t len = first & 0xFF;
  if(BOOST_JSON_UNLIKELY(end - p < len))
  break;
- if(BOOST_JSON_UNLIKELY(! is_valid_utf8(p, first)))
+ if(BOOST_JSON_UNLIKELY(! is_valid_utf8_no_inline(p, first)))
  break;
  p += len;
  }
@@ -185,7 +185,7 @@ count_valid<false>(
  uint8_t len = first & 0xFF;
  if(BOOST_JSON_UNLIKELY(end - p < len))
  break;
- if(BOOST_JSON_UNLIKELY(! is_valid_utf8(p, first)))
+ if(BOOST_JSON_UNLIKELY(! is_valid_utf8_no_inline(p, first)))
  break;
  p += len;
  }

include/boost/json/detail/utf8.hpp

@@ -25,10 +25,8 @@ template<int N>
 std::uint32_t
 load_little_endian(void const* p)
 {
- std::uint32_t v = 0;
- std::memcpy(&v, p, N);
- endian::little_to_native_inplace(v);
- return v;
+ auto const up = reinterpret_cast<unsigned char const*>(p);
+ return endian::endian_load<std::uint32_t, N, endian::order::little>(up);
 }
 
 inline
@@ -70,7 +68,7 @@ inline
 bool
 is_valid_utf8(const char* p, uint16_t first)
 {
- uint32_t v;
+ std::uint32_t v;
  switch(first >> 8)
  {
  default:
@@ -81,38 +79,46 @@ is_valid_utf8(const char* p, uint16_t first)
  v = load_little_endian<2>(p);
  return (v & 0xC000) == 0x8000;
 
- // 3 bytes, second byte [A0, BF]
- case 2:
+  // 3 bytes, second byte [A0, BF]
+  case 2:
  v = load_little_endian<3>(p);
  return (v & 0xC0E000) == 0x80A000;
 
- // 3 bytes, second byte [80, BF]
- case 3:
+  // 3 bytes, second byte [80, BF]
+  case 3:
  v = load_little_endian<3>(p);
  return (v & 0xC0C000) == 0x808000;
 
- // 3 bytes, second byte [80, 9F]
- case 4:
+  // 3 bytes, second byte [80, 9F]
+  case 4:
  v = load_little_endian<3>(p);
  return (v & 0xC0E000) == 0x808000;
 
- // 4 bytes, second byte [90, BF]
- case 5:
+  // 4 bytes, second byte [90, BF]
+  case 5:
  v = load_little_endian<4>(p);
  return (v & 0xC0C0FF00) + 0x7F7F7000 <= 0x2F00;
 
- // 4 bytes, second byte [80, BF]
- case 6:
+  // 4 bytes, second byte [80, BF]
+  case 6:
  v = load_little_endian<4>(p);
  return (v & 0xC0C0C000) == 0x80808000;
 
- // 4 bytes, second byte [80, 8F]
- case 7:
+  // 4 bytes, second byte [80, 8F]
+  case 7:
  v = load_little_endian<4>(p);
  return (v & 0xC0C0F000) == 0x80808000;
  }
 }
 
+BOOST_NOINLINE
+inline
+bool
+is_valid_utf8_no_inline(const char* p, uint16_t first)
+{
+ return is_valid_utf8(p, first);
+}
+
 class utf8_sequence
 {
  char seq_[4];