daw_json_string_util.h

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// Copyright (c) Darrell Wright
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// Official repository: https://github.com/beached/daw_json_link
//
 
#pragma once
 
#include "version.h"
 
#include "daw_json_exec_modes.h"
#include "daw_json_parse_policy_policy_details.h"
#include "daw_not_const_ex_functions.h"
 
#include <daw/daw_is_constant_evaluated.h>
#include <daw/daw_likely.h>
#include <daw/daw_traits.h>
 
#include <cstring>
 
namespace daw::json {
  inline namespace DAW_JSON_VER {
    namespace json_details {
      template<char c, typename ExecTag, bool expect_long, typename CharT>
      DAW_ATTRIB_NONNULL( )
      DAW_ATTRIB_RET_NONNULL DAW_ATTRIB_FLATINLINE
        static inline constexpr CharT *memchr_unchecked( CharT *first,
                                                         CharT *last ) {
#if DAW_HAS_BUILTIN( __builtin_char_memchr )
        if constexpr( expect_long ) {
          return __builtin_char_memchr(
            first, '"', static_cast<std::size_t>( last - first ) );
        } else
#else
#if defined( DAW_IS_CONSTANT_EVALUATED )
        bool is_cxeval =
          DAW_IS_CONSTANT_EVALUATED( ) | DAW_CAN_CONSTANT_EVAL( first );
#else
        bool is_cxeval = DAW_CAN_CONSTANT_EVAL( first );
#endif
        if constexpr( expect_long ) {
          if( ( not is_cxeval ) |
              daw::traits::not_same_v<ExecTag, constexpr_exec_tag> ) {
            return static_cast<CharT *>(
              std::memchr( static_cast<void const *>( first ), '"',
                           static_cast<std::size_t>( last - first ) ) );
          }
          (void)last;
          while( *first != c ) {
            ++first;
          }
          return first;
        } else
#endif
        {
          (void)last;
          while( *first != c ) {
            ++first;
          }
          return first;
        }
      }
 
      template<char c, typename ExecTag, bool expect_long, typename CharT>
      DAW_ATTRIB_NONNULL( )
      DAW_ATTRIB_RET_NONNULL DAW_ATTRIB_FLATINLINE
        static inline constexpr CharT *memchr_checked( CharT *first,
                                                       CharT *last ) {
#if DAW_HAS_BUILTIN( __builtin_char_memchr )
        if constexpr( expect_long ) {
          return __builtin_char_memchr(
            first, '"', static_cast<std::size_t>( last - first ) );
        } else
#elif DAW_HAS_BUILTIN( __builtin_memchr )
        if constexpr( expect_long ) {
          return static_cast<CharT *>( __builtin_memchr(
            first, '"', static_cast<std::size_t>( last - first ) ) );
        } else
#else
#if defined( DAW_IS_CONSTANT_EVALUATED )
        bool is_cxeval =
          DAW_IS_CONSTANT_EVALUATED( ) | DAW_CAN_CONSTANT_EVAL( first );
#else
        bool is_cxeval = DAW_CAN_CONSTANT_EVAL( first );
#endif
        if constexpr( expect_long ) {
          if( ( not is_cxeval ) |
              daw::traits::not_same_v<ExecTag, constexpr_exec_tag> ) {
            return static_cast<CharT *>(
              std::memchr( static_cast<void const *>( first ), '"',
                           static_cast<std::size_t>( last - first ) ) );
          }
          while( DAW_LIKELY( first < last ) and *first != c ) {
            ++first;
          }
          return first;
        } else
#endif
        {
          while( DAW_LIKELY( first < last ) and *first != c ) {
            ++first;
          }
          return first;
        }
      }
 
      template<typename ExecTag, bool expect_long, char... chars,
               typename CharT>
      DAW_ATTRIB_NONNULL( )
      DAW_ATTRIB_RET_NONNULL DAW_ATTRIB_FLATINLINE
        static inline constexpr CharT *mempbrk_unchecked( CharT *first,
                                                          CharT * /*last*/ ) {
#if DAW_HAS_BUILTIN( __builtin_strpbrk )
        if constexpr( expect_long ) {
          constexpr char const needles[]{ chars..., '\0' };
          CharT *res = __builtin_strpbrk( first, needles );
#if not defined( NDEBUG )
          daw_json_ensure( res != nullptr, ErrorReason::UnexpectedEndOfData );
#endif
          return res;
        } else
#else
#if defined( DAW_IS_CONSTANT_EVALUATED )
        bool is_cxeval =
          DAW_IS_CONSTANT_EVALUATED( ) | DAW_CAN_CONSTANT_EVAL( first );
#else
        bool is_cxeval = DAW_CAN_CONSTANT_EVAL( first );
#endif
        if constexpr( expect_long ) {
          if( ( not is_cxeval ) |
              daw::traits::not_same_v<ExecTag, constexpr_exec_tag> ) {
            constexpr char const needles[]{ chars..., '\0' };
            CharT *res = std::strpbrk( first, needles );
#if not defined( NDEBUG )
            daw_json_ensure( res != nullptr, ErrorReason::UnexpectedEndOfData );
#endif
            return res;
          }
          while( not parse_policy_details::in<chars...>( *first ) ) {
            ++first;
          }
          return first;
        } else
#endif
        {
          while( not parse_policy_details::in<chars...>( *first ) ) {
            ++first;
          }
          return first;
        }
      }
 
      template<typename ExecTag, bool expect_long, char... chars,
               typename CharT>
      DAW_ATTRIB_NONNULL( )
      DAW_ATTRIB_RET_NONNULL DAW_ATTRIB_FLATINLINE
        static inline constexpr CharT *mempbrk_checked( CharT *first,
                                                        CharT *last ) {
        if constexpr( expect_long ) {
#if defined( DAW_IS_CONSTANT_EVALUATED )
          bool is_cxeval =
            DAW_IS_CONSTANT_EVALUATED( ) | DAW_CAN_CONSTANT_EVAL( first );
#else
          bool is_cxeval = DAW_CAN_CONSTANT_EVAL( first );
#endif
          if( ( not is_cxeval ) |
              daw::traits::not_same_v<ExecTag, constexpr_exec_tag> ) {
 
            return mem_move_to_next_of<false, chars...>( ExecTag{}, first, last );
          }
          while( DAW_LIKELY( first < last ) and
                 not parse_policy_details::in<chars...>( *first ) ) {
            ++first;
          }
          return first;
        } else {
          while( DAW_LIKELY( first < last ) and
                 not parse_policy_details::in<chars...>( *first ) ) {
            ++first;
          }
          return first;
        }
      }
 
      template<bool is_unchecked_input, typename ExecTag, bool expect_long,
               char... chars, typename CharT>
      DAW_ATTRIB_NONNULL( )
      DAW_ATTRIB_RET_NONNULL DAW_ATTRIB_FLATINLINE
        static inline constexpr CharT *mempbrk( CharT *first, CharT *last ) {
 
        if constexpr( is_unchecked_input ) {
          return mempbrk_unchecked<ExecTag, expect_long, chars...>( first,
                                                                    last );
        } else {
          return mempbrk_checked<ExecTag, expect_long, chars...>( first, last );
        }
      }
    } // namespace json_details
  } // namespace DAW_JSON_VER
} // namespace daw::json