Added thirdparty: boost library

thirdparty/include/boost/json/detail/utf8.hpp

@@ -0,0 +1,199 @@
+//
+// Copyright (c) 2020 Krystian Stasiowski (sdkrystian@gmail.com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// Official repository: https://github.com/boostorg/json
+//
+
+#ifndef BOOST_JSON_DETAIL_UTF8_HPP
+#define BOOST_JSON_DETAIL_UTF8_HPP
+
+#include <boost/json/detail/config.hpp>
+
+#include <cstddef>
+#include <cstring>
+#include <cstdint>
+
+namespace boost {
+namespace json {
+namespace detail {
+
+template<int N>
+std::uint32_t
+load_little_endian(void const* p)
+{
+    std::uint32_t v = 0;
+    std::memcpy(&v, p, N);
+#ifdef BOOST_JSON_BIG_ENDIAN
+    v = ((v & 0xFF000000) >> 24) |
+        ((v & 0x00FF0000) >>  8) |
+        ((v & 0x0000FF00) <<  8) |
+        ((v & 0x000000FF) << 24);
+#endif
+    return v;
+}
+
+inline
+uint16_t
+classify_utf8(char c)
+{
+    // 0x000 = invalid
+    // 0x102 = 2 bytes, second byte [80, BF]
+    // 0x203 = 3 bytes, second byte [A0, BF]
+    // 0x303 = 3 bytes, second byte [80, BF]
+    // 0x403 = 3 bytes, second byte [80, 9F]
+    // 0x504 = 4 bytes, second byte [90, BF]
+    // 0x604 = 4 bytes, second byte [80, BF]
+    // 0x704 = 4 bytes, second byte [80, 8F]
+    static constexpr uint16_t first[128]
+    {
+       0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
+       0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
+       0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
+       0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
+       0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
+       0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
+       0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
+       0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
+
+       0x000, 0x000, 0x102, 0x102, 0x102, 0x102, 0x102, 0x102,
+       0x102, 0x102, 0x102, 0x102, 0x102, 0x102, 0x102, 0x102,
+       0x102, 0x102, 0x102, 0x102, 0x102, 0x102, 0x102, 0x102,
+       0x102, 0x102, 0x102, 0x102, 0x102, 0x102, 0x102, 0x102,
+       0x203, 0x303, 0x303, 0x303, 0x303, 0x303, 0x303, 0x303,
+       0x303, 0x303, 0x303, 0x303, 0x303, 0x403, 0x303, 0x303,
+       0x504, 0x604, 0x604, 0x604, 0x704, 0x000, 0x000, 0x000,
+       0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000,
+    };
+    return first[static_cast<unsigned char>(c & 0x7F)];
+}
+
+inline
+bool
+is_valid_utf8(const char* p, uint16_t first)
+{
+    uint32_t v;
+    switch(first >> 8)
+    {
+    default:
+        return false;
+
+    // 2 bytes, second byte [80, BF]
+    case 1:
+        v = load_little_endian<2>(p);
+        return (v & 0xC000) == 0x8000;
+
+    // 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:
+        v = load_little_endian<3>(p);
+        return (v & 0xC0C000) == 0x808000;
+
+    // 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:
+        v = load_little_endian<4>(p);
+        return (v & 0xC0C0FF00) + 0x7F7F7000 <= 0x2F00;
+
+    // 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:
+        v = load_little_endian<4>(p);
+        return (v & 0xC0C0F000) == 0x80808000;
+    }
+}
+
+class utf8_sequence
+{
+    char seq_[4];
+    uint16_t first_;
+    uint8_t size_;
+
+public:
+    void
+    save(
+        const char* p,
+        std::size_t remain) noexcept
+    {
+        first_ = classify_utf8(*p );
+        if(remain >= length())
+            size_ = length();
+        else
+            size_ = static_cast<uint8_t>(remain);
+        std::memcpy(seq_, p, size_);
+    }
+
+    uint8_t
+    length() const noexcept
+    {
+        return first_ & 0xFF;
+    }
+
+    bool
+    complete() const noexcept
+    {
+        return size_ >= length();
+    }
+
+    // returns true if complete
+    bool
+    append(
+        const char* p,
+        std::size_t remain) noexcept
+    {
+        if(BOOST_JSON_UNLIKELY(needed() == 0))
+            return true;
+        if(BOOST_JSON_LIKELY(remain >= needed()))
+        {
+            std::memcpy(
+                seq_ + size_, p, needed());
+            size_ = length();
+            return true;
+        }
+        if(BOOST_JSON_LIKELY(remain > 0))
+        {
+            std::memcpy(seq_ + size_, p, remain);
+            size_ += static_cast<uint8_t>(remain);
+        }
+        return false;
+    }
+
+    const char*
+    data() const noexcept
+    {
+        return seq_;
+    }
+
+    uint8_t
+    needed() const noexcept
+    {
+        return length() - size_;
+    }
+
+    bool
+    valid() const noexcept
+    {
+        BOOST_ASSERT(size_ >= length());
+        return is_valid_utf8(seq_, first_);
+    }
+};
+
+} // detail
+} // namespace json
+} // namespace boost
+
+#endif