| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | // Copyright 2023 Matt Borland | ||
| 2 | // Distributed under the Boost Software License, Version 1.0. | ||
| 3 | // https://www.boost.org/LICENSE_1_0.txt | ||
| 4 | |||
| 5 | #ifndef BOOST_JSON_DETAIL_CHARCONV_DETAIL_INTEGER_SEARCH_TREES_HPP | ||
| 6 | #define BOOST_JSON_DETAIL_CHARCONV_DETAIL_INTEGER_SEARCH_TREES_HPP | ||
| 7 | |||
| 8 | // https://stackoverflow.com/questions/1489830/efficient-way-to-determine-number-of-digits-in-an-integer?page=1&tab=scoredesc#tab-top | ||
| 9 | // https://graphics.stanford.edu/~seander/bithacks.html | ||
| 10 | |||
| 11 | #include <boost/json/detail/charconv/detail/config.hpp> | ||
| 12 | #include <limits> | ||
| 13 | #include <array> | ||
| 14 | #include <cstdint> | ||
| 15 | |||
| 16 | namespace boost { namespace json { namespace detail { namespace charconv { namespace detail { | ||
| 17 | |||
| 18 | // Generic solution | ||
| 19 | template <typename T> | ||
| 20 | BOOST_JSON_CXX14_CONSTEXPR int num_digits(T x) noexcept | ||
| 21 | { | ||
| 22 | int digits = 0; | ||
| 23 | |||
| 24 | while (x) | ||
| 25 | { | ||
| 26 | x /= 10; | ||
| 27 | ++digits; | ||
| 28 | } | ||
| 29 | |||
| 30 | return digits; | ||
| 31 | } | ||
| 32 | |||
| 33 | template <> | ||
| 34 | BOOST_JSON_CXX14_CONSTEXPR int num_digits(std::uint32_t x) noexcept | ||
| 35 | { | ||
| 36 | if (x >= UINT32_C(10000)) | ||
| 37 | { | ||
| 38 | if (x >= UINT32_C(10000000)) | ||
| 39 | { | ||
| 40 | if (x >= UINT32_C(100000000)) | ||
| 41 | { | ||
| 42 | if (x >= UINT32_C(1000000000)) | ||
| 43 | { | ||
| 44 | return 10; | ||
| 45 | } | ||
| 46 | return 9; | ||
| 47 | } | ||
| 48 | return 8; | ||
| 49 | } | ||
| 50 | |||
| 51 | else if (x >= UINT32_C(100000)) | ||
| 52 | { | ||
| 53 | if (x >= UINT32_C(1000000)) | ||
| 54 | { | ||
| 55 | return 7; | ||
| 56 | } | ||
| 57 | return 6; | ||
| 58 | } | ||
| 59 | return 5; | ||
| 60 | } | ||
| 61 | else if (x >= UINT32_C(100)) | ||
| 62 | { | ||
| 63 | if (x >= UINT32_C(1000)) | ||
| 64 | { | ||
| 65 | return 4; | ||
| 66 | } | ||
| 67 | return 3; | ||
| 68 | } | ||
| 69 | else if (x >= UINT32_C(10)) | ||
| 70 | { | ||
| 71 | return 2; | ||
| 72 | } | ||
| 73 | |||
| 74 | return 1; | ||
| 75 | } | ||
| 76 | |||
| 77 | template <> | ||
| 78 | ✗ | BOOST_JSON_CXX14_CONSTEXPR int num_digits(std::uint64_t x) noexcept | |
| 79 | { | ||
| 80 | ✗ | if (x >= UINT64_C(10000000000)) | |
| 81 | { | ||
| 82 | ✗ | if (x >= UINT64_C(100000000000000)) | |
| 83 | { | ||
| 84 | ✗ | if (x >= UINT64_C(10000000000000000)) | |
| 85 | { | ||
| 86 | ✗ | if (x >= UINT64_C(100000000000000000)) | |
| 87 | { | ||
| 88 | ✗ | if (x >= UINT64_C(1000000000000000000)) | |
| 89 | { | ||
| 90 | ✗ | if (x >= UINT64_C(10000000000000000000)) | |
| 91 | { | ||
| 92 | ✗ | return 20; | |
| 93 | } | ||
| 94 | ✗ | return 19; | |
| 95 | } | ||
| 96 | ✗ | return 18; | |
| 97 | } | ||
| 98 | ✗ | return 17; | |
| 99 | } | ||
| 100 | ✗ | else if (x >= UINT64_C(1000000000000000)) | |
| 101 | { | ||
| 102 | ✗ | return 16; | |
| 103 | } | ||
| 104 | ✗ | return 15; | |
| 105 | } | ||
| 106 | ✗ | if (x >= UINT64_C(1000000000000)) | |
| 107 | { | ||
| 108 | ✗ | if (x >= UINT64_C(10000000000000)) | |
| 109 | { | ||
| 110 | ✗ | return 14; | |
| 111 | } | ||
| 112 | ✗ | return 13; | |
| 113 | } | ||
| 114 | ✗ | if (x >= UINT64_C(100000000000)) | |
| 115 | { | ||
| 116 | ✗ | return 12; | |
| 117 | } | ||
| 118 | ✗ | return 11; | |
| 119 | } | ||
| 120 | ✗ | else if (x >= UINT64_C(100000)) | |
| 121 | { | ||
| 122 | ✗ | if (x >= UINT64_C(10000000)) | |
| 123 | { | ||
| 124 | ✗ | if (x >= UINT64_C(100000000)) | |
| 125 | { | ||
| 126 | ✗ | if (x >= UINT64_C(1000000000)) | |
| 127 | { | ||
| 128 | ✗ | return 10; | |
| 129 | } | ||
| 130 | ✗ | return 9; | |
| 131 | } | ||
| 132 | ✗ | return 8; | |
| 133 | } | ||
| 134 | ✗ | if (x >= UINT64_C(1000000)) | |
| 135 | { | ||
| 136 | ✗ | return 7; | |
| 137 | } | ||
| 138 | ✗ | return 6; | |
| 139 | } | ||
| 140 | ✗ | if (x >= UINT64_C(100)) | |
| 141 | { | ||
| 142 | ✗ | if (x >= UINT64_C(1000)) | |
| 143 | { | ||
| 144 | ✗ | if (x >= UINT64_C(10000)) | |
| 145 | { | ||
| 146 | ✗ | return 5; | |
| 147 | } | ||
| 148 | ✗ | return 4; | |
| 149 | } | ||
| 150 | ✗ | return 3; | |
| 151 | } | ||
| 152 | ✗ | if (x >= UINT64_C(10)) | |
| 153 | { | ||
| 154 | ✗ | return 2; | |
| 155 | } | ||
| 156 | ✗ | return 1; | |
| 157 | } | ||
| 158 | |||
| 159 | #ifdef BOOST_HAS_INT128 | ||
| 160 | static constexpr std::array<std::uint64_t, 20> powers_of_10 = | ||
| 161 | {{ | ||
| 162 | UINT64_C(1), UINT64_C(10), UINT64_C(100), UINT64_C(1000), UINT64_C(10000), UINT64_C(100000), UINT64_C(1000000), | ||
| 163 | UINT64_C(10000000), UINT64_C(100000000), UINT64_C(1000000000), UINT64_C(10000000000), UINT64_C(100000000000), | ||
| 164 | UINT64_C(1000000000000), UINT64_C(10000000000000), UINT64_C(100000000000000), UINT64_C(1000000000000000), | ||
| 165 | UINT64_C(10000000000000000), UINT64_C(100000000000000000), UINT64_C(1000000000000000000), UINT64_C(10000000000000000000) | ||
| 166 | }}; | ||
| 167 | |||
| 168 | // Assume that if someone is using 128 bit ints they are favoring the top end of the range | ||
| 169 | // Max value is 340,282,366,920,938,463,463,374,607,431,768,211,455 (39 digits) | ||
| 170 | BOOST_JSON_CXX14_CONSTEXPR int num_digits(boost::uint128_type x) noexcept | ||
| 171 | { | ||
| 172 | // There is not literal for boost::uint128_type so we need to calculate them using the max value of the | ||
| 173 | // std::uint64_t powers of 10 | ||
| 174 | constexpr boost::uint128_type digits_39 = static_cast<boost::uint128_type>(UINT64_C(10000000000000000000)) * | ||
| 175 | static_cast<boost::uint128_type>(UINT64_C(10000000000000000000)); | ||
| 176 | |||
| 177 | constexpr boost::uint128_type digits_38 = digits_39 / 10; | ||
| 178 | constexpr boost::uint128_type digits_37 = digits_38 / 10; | ||
| 179 | constexpr boost::uint128_type digits_36 = digits_37 / 10; | ||
| 180 | constexpr boost::uint128_type digits_35 = digits_36 / 10; | ||
| 181 | constexpr boost::uint128_type digits_34 = digits_35 / 10; | ||
| 182 | constexpr boost::uint128_type digits_33 = digits_34 / 10; | ||
| 183 | constexpr boost::uint128_type digits_32 = digits_33 / 10; | ||
| 184 | constexpr boost::uint128_type digits_31 = digits_32 / 10; | ||
| 185 | constexpr boost::uint128_type digits_30 = digits_31 / 10; | ||
| 186 | constexpr boost::uint128_type digits_29 = digits_30 / 10; | ||
| 187 | constexpr boost::uint128_type digits_28 = digits_29 / 10; | ||
| 188 | constexpr boost::uint128_type digits_27 = digits_28 / 10; | ||
| 189 | constexpr boost::uint128_type digits_26 = digits_27 / 10; | ||
| 190 | constexpr boost::uint128_type digits_25 = digits_26 / 10; | ||
| 191 | constexpr boost::uint128_type digits_24 = digits_25 / 10; | ||
| 192 | constexpr boost::uint128_type digits_23 = digits_24 / 10; | ||
| 193 | constexpr boost::uint128_type digits_22 = digits_23 / 10; | ||
| 194 | constexpr boost::uint128_type digits_21 = digits_22 / 10; | ||
| 195 | |||
| 196 | return (x >= digits_39) ? 39 : | ||
| 197 | (x >= digits_38) ? 38 : | ||
| 198 | (x >= digits_37) ? 37 : | ||
| 199 | (x >= digits_36) ? 36 : | ||
| 200 | (x >= digits_35) ? 35 : | ||
| 201 | (x >= digits_34) ? 34 : | ||
| 202 | (x >= digits_33) ? 33 : | ||
| 203 | (x >= digits_32) ? 32 : | ||
| 204 | (x >= digits_31) ? 31 : | ||
| 205 | (x >= digits_30) ? 30 : | ||
| 206 | (x >= digits_29) ? 29 : | ||
| 207 | (x >= digits_28) ? 28 : | ||
| 208 | (x >= digits_27) ? 27 : | ||
| 209 | (x >= digits_26) ? 26 : | ||
| 210 | (x >= digits_25) ? 25 : | ||
| 211 | (x >= digits_24) ? 24 : | ||
| 212 | (x >= digits_23) ? 23 : | ||
| 213 | (x >= digits_22) ? 22 : | ||
| 214 | (x >= digits_21) ? 21 : | ||
| 215 | (x >= powers_of_10[19]) ? 20 : | ||
| 216 | (x >= powers_of_10[18]) ? 19 : | ||
| 217 | (x >= powers_of_10[17]) ? 18 : | ||
| 218 | (x >= powers_of_10[16]) ? 17 : | ||
| 219 | (x >= powers_of_10[15]) ? 16 : | ||
| 220 | (x >= powers_of_10[14]) ? 15 : | ||
| 221 | (x >= powers_of_10[13]) ? 14 : | ||
| 222 | (x >= powers_of_10[12]) ? 13 : | ||
| 223 | (x >= powers_of_10[11]) ? 12 : | ||
| 224 | (x >= powers_of_10[10]) ? 11 : | ||
| 225 | (x >= powers_of_10[9]) ? 10 : | ||
| 226 | (x >= powers_of_10[8]) ? 9 : | ||
| 227 | (x >= powers_of_10[7]) ? 8 : | ||
| 228 | (x >= powers_of_10[6]) ? 7 : | ||
| 229 | (x >= powers_of_10[5]) ? 6 : | ||
| 230 | (x >= powers_of_10[4]) ? 5 : | ||
| 231 | (x >= powers_of_10[3]) ? 4 : | ||
| 232 | (x >= powers_of_10[2]) ? 3 : | ||
| 233 | (x >= powers_of_10[1]) ? 2 : | ||
| 234 | (x >= powers_of_10[0]) ? 1 : 0; | ||
| 235 | } | ||
| 236 | #endif | ||
| 237 | |||
| 238 | }}}}} // Namespace boost::json::detail::charconv::detail | ||
| 239 | |||
| 240 | #endif // BOOST_JSON_DETAIL_CHARCONV_DETAIL_INTEGER_SEARCH_TREES_HPP | ||
| 241 |