Merge branch 'json-view/21-images' into json-view/22-view-dump-fast

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

include/nlohmann/detail/bit_ops.hpp

@@ -9,12 +9,15 @@
 #pragma once
 
 #include <cstdint> // uint64_t
+#if !defined(__SIZEOF_INT128__) && defined(_MSC_VER) && (defined(_M_X64) || defined(_M_ARM64))
+    #include <intrin0.h> // __umulh, _umul128
+#endif
 
 #include <nlohmann/detail/abi_macros.hpp>
 
 // Portable bit-level helpers for the number and string scanners. They use
-// compiler builtins where available and plain C++ otherwise, so they need no
-// platform headers and work regardless of byte order.
+// compiler builtins or platform-specific intrinsics where available and plain
+// C++ otherwise, so they work regardless of byte order.
 
 NLOHMANN_JSON_NAMESPACE_BEGIN
 namespace detail
@@ -71,6 +74,12 @@ inline uint128_parts full_multiplication(std::uint64_t a, std::uint64_t b) noexc
     __extension__ using uint128 = unsigned __int128;
     const uint128 r = static_cast<uint128>(a) * b;
     return {static_cast<std::uint64_t>(r), static_cast<std::uint64_t>(r >> 64u)};
+#elif defined(_MSC_VER) && defined(_M_X64)
+    std::uint64_t high = 0;
+    const std::uint64_t low = _umul128(a, b, &high);
+    return {low, high};
+#elif defined(_MSC_VER) && defined(_M_ARM64)
+    return {a * b, __umulh(a, b)};
 #else
     const std::uint64_t a_lo = a & 0xFFFFFFFFu;
     const std::uint64_t a_hi = a >> 32u;

include/nlohmann/detail/view/document_data.hpp

@@ -40,10 +40,10 @@ struct document_data
     std::size_t tape_cap = 0;
     node* inline_tape = nullptr; ///< node array allocated together with this header
     std::size_t inline_cap = 0;
-    std::string arena{}; ///< decoded strings that contained escapes // NOLINT(readability-redundant-member-init)
+    std::string arena; ///< decoded strings that contained escapes
     std::size_t arena_size = 0; ///< bytes of decoded strings at base[1] (the arena, or those of a loaded image)
-    std::string owned{}; ///< owned copy of the input, if any // NOLINT(readability-redundant-member-init)
-    std::vector<std::uint8_t> owned_image{}; ///< a loaded image the document owns (the text and the decoded strings point into it) // NOLINT(readability-redundant-member-init)
+    std::string owned; ///< owned copy of the input, if any
+    std::vector<std::uint8_t> owned_image; ///< a loaded image the document owns (the text and the decoded strings point into it)
 
     // hash indexes of large objects (see object_index.hpp)
     static constexpr std::uint32_t index_min_members = 128;
@@ -52,9 +52,9 @@ struct document_data
         std::size_t start;  ///< first slot in index_slots
         std::uint32_t mask; ///< slot count - 1 (a power of two minus one)
     };
-    std::vector<object_index> indexes{}; // NOLINT(readability-redundant-member-init)
-    std::vector<std::uint32_t> index_slots{}; // NOLINT(readability-redundant-member-init)
-    std::vector<std::uint32_t> large_objects{}; ///< positions of the objects to index (noted while parsing) // NOLINT(readability-redundant-member-init)
+    std::vector<object_index> indexes;
+    std::vector<std::uint32_t> index_slots;
+    std::vector<std::uint32_t> large_objects; ///< positions of the objects to index (noted while parsing)
     std::array<const char*, 4> base = {{nullptr, nullptr, nullptr, nullptr}}; ///< string bases: source, arena, edit arena (indexed by flags & node_flags::storage)
     bool discarded = true;
 

include/nlohmann/detail/view/edit_storage.hpp

@@ -177,7 +177,7 @@ inline node* block_of(document_data& d, node* n, std::size_t extra)
 /// still covers its original subtree.
 inline node* find_parent(const document_data& d, const node* target)
 {
-    const std::less<const node*> lt;
+    const std::less<const node*> lt{};
     const node* lo = d.tape;
     const node* hi = d.tape + d.tape_size;
     const node* c = d.tape;

include/nlohmann/detail/view/scan.hpp

@@ -85,7 +85,9 @@ NLOHMANN_VIEW_ALWAYS_INLINE const unsigned char* scan_string_run(const unsigned
 #define NLOHMANN_VIEW_STEP(i) if (NLOHMANN_VIEW_LIKELY(plain[p[i]] != 0)) {} else { p += (i); goto stop; }
             NLOHMANN_VIEW_STEP(0) NLOHMANN_VIEW_STEP(1) NLOHMANN_VIEW_STEP(2) NLOHMANN_VIEW_STEP(3)
             NLOHMANN_VIEW_STEP(4) NLOHMANN_VIEW_STEP(5) NLOHMANN_VIEW_STEP(6) NLOHMANN_VIEW_STEP(7)
-            if (!Value || !NLOHMANN_VIEW_VECTOR)
+#if NLOHMANN_VIEW_VECTOR
+            if (!Value) // (a plain `!Value || !NLOHMANN_VIEW_VECTOR` is a constant condition for MSVC, C4127)
+#endif
             {
                 NLOHMANN_VIEW_STEP(8) NLOHMANN_VIEW_STEP(9) NLOHMANN_VIEW_STEP(10) NLOHMANN_VIEW_STEP(11)
                 NLOHMANN_VIEW_STEP(12) NLOHMANN_VIEW_STEP(13) NLOHMANN_VIEW_STEP(14) NLOHMANN_VIEW_STEP(15)

include/nlohmann/detail/view/simd.hpp

@@ -26,6 +26,9 @@
 // used where the CPU has SSSE3 (all x86-64 CPUs since about 2011), else the
 // portable check. JSON_VIEW_USE_SSSE3 skips the CPU check (for code compiled
 // for SSSE3 anyway); JSON_VIEW_NO_SIMD selects the portable code.
+// NLOHMANN_VIEW_NO_TARGET_ATTRIBUTE (set by the GCC module interface, where GCC
+// ignores the target attribute and then rejects the SSSE3 intrinsics) keeps the
+// check portable without disabling the SSE2 code.
 #if !defined(JSON_VIEW_NO_SIMD) && defined(__aarch64__) && (defined(__GNUC__) || defined(__clang__)) && NLOHMANN_VIEW_LITTLE_ENDIAN
     #include <arm_neon.h>
     #define NLOHMANN_VIEW_NEON 1
@@ -44,7 +47,7 @@
 #else
     #define NLOHMANN_VIEW_SSSE3 0 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
 #endif
-#if NLOHMANN_VIEW_SSE2 && !NLOHMANN_VIEW_SSSE3 && ((defined(__clang__) && __clang_major__ >= 4) || (defined(__GNUC__) && !defined(__clang__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 9))))
+#if NLOHMANN_VIEW_SSE2 && !NLOHMANN_VIEW_SSSE3 && !defined(NLOHMANN_VIEW_NO_TARGET_ATTRIBUTE) && ((defined(__clang__) && __clang_major__ >= 4) || (defined(__GNUC__) && !defined(__clang__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 9))))
     // (GCC before 4.9 has no SSSE3 intrinsics without -mssse3)
     #include <cpuid.h>
     #include <tmmintrin.h>

include/nlohmann/json_view.hpp

@@ -705,11 +705,19 @@ class basic_json_view
         return detail::view::view_side<BasicJsonType, basic_json_view>(v);
     }
 
+    /// the template argument as a runtime condition: testing it directly in
+    /// `Editable && ...` makes the condition constant, which MSVC reports as
+    /// C4127
+    static bool editable() noexcept
+    {
+        return Editable;
+    }
+
     /// the number of source bytes of this value (estimated for values with
     /// decoded strings)
     std::size_t source_extent() const noexcept
     {
-        if (Editable && m_doc->edits != nullptr)
+        if (editable() && m_doc->edits != nullptr)
         {
             // positions of moved and new values are not source offsets
             return m_node == m_doc->tape ? m_doc->size + m_doc->edits->text_used : 64;