diff options
Diffstat (limited to 'absl/strings/numbers.cc')
| -rw-r--r-- | absl/strings/numbers.cc | 136 |
1 files changed, 132 insertions, 4 deletions
diff --git a/absl/strings/numbers.cc b/absl/strings/numbers.cc index 68c26dd6..966d94bd 100644 --- a/absl/strings/numbers.cc +++ b/absl/strings/numbers.cc @@ -31,8 +31,8 @@ #include <utility> #include "absl/base/attributes.h" -#include "absl/base/internal/bits.h" #include "absl/base/internal/raw_logging.h" +#include "absl/numeric/bits.h" #include "absl/strings/ascii.h" #include "absl/strings/charconv.h" #include "absl/strings/escaping.h" @@ -46,8 +46,13 @@ ABSL_NAMESPACE_BEGIN bool SimpleAtof(absl::string_view str, float* out) { *out = 0.0; str = StripAsciiWhitespace(str); + // std::from_chars doesn't accept an initial +, but SimpleAtof does, so if one + // is present, skip it, while avoiding accepting "+-0" as valid. if (!str.empty() && str[0] == '+') { str.remove_prefix(1); + if (!str.empty() && str[0] == '-') { + return false; + } } auto result = absl::from_chars(str.data(), str.data() + str.size(), *out); if (result.ec == std::errc::invalid_argument) { @@ -72,8 +77,13 @@ bool SimpleAtof(absl::string_view str, float* out) { bool SimpleAtod(absl::string_view str, double* out) { *out = 0.0; str = StripAsciiWhitespace(str); + // std::from_chars doesn't accept an initial +, but SimpleAtod does, so if one + // is present, skip it, while avoiding accepting "+-0" as valid. if (!str.empty() && str[0] == '+') { str.remove_prefix(1); + if (!str.empty() && str[0] == '-') { + return false; + } } auto result = absl::from_chars(str.data(), str.data() + str.size(), *out); if (result.ec == std::errc::invalid_argument) { @@ -303,7 +313,7 @@ static std::pair<uint64_t, uint64_t> Mul32(std::pair<uint64_t, uint64_t> num, uint64_t bits128_up = (bits96_127 >> 32) + (bits64_127 < bits64_95); if (bits128_up == 0) return {bits64_127, bits0_63}; - int shift = 64 - base_internal::CountLeadingZeros64(bits128_up); + auto shift = static_cast<unsigned>(bit_width(bits128_up)); uint64_t lo = (bits0_63 >> shift) + (bits64_127 << (64 - shift)); uint64_t hi = (bits64_127 >> shift) + (bits128_up << (64 - shift)); return {hi, lo}; @@ -334,7 +344,7 @@ static std::pair<uint64_t, uint64_t> PowFive(uint64_t num, int expfive) { 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5, 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5 * 5}; result = Mul32(result, powers_of_five[expfive & 15]); - int shift = base_internal::CountLeadingZeros64(result.first); + int shift = countl_zero(result.first); if (shift != 0) { result.first = (result.first << shift) + (result.second >> (64 - shift)); result.second = (result.second << shift); @@ -736,9 +746,18 @@ struct LookupTables { X / 35, X / 36, \ } +// This kVmaxOverBase is generated with +// for (int base = 2; base < 37; ++base) { +// absl::uint128 max = std::numeric_limits<absl::uint128>::max(); +// auto result = max / base; +// std::cout << " MakeUint128(" << absl::Uint128High64(result) << "u, " +// << absl::Uint128Low64(result) << "u),\n"; +// } +// See https://godbolt.org/z/aneYsb +// // uint128& operator/=(uint128) is not constexpr, so hardcode the resulting // array to avoid a static initializer. -template <> +template<> const uint128 LookupTables<uint128>::kVmaxOverBase[] = { 0, 0, @@ -779,6 +798,111 @@ const uint128 LookupTables<uint128>::kVmaxOverBase[] = { MakeUint128(512409557603043100u, 8198552921648689607u), }; +// This kVmaxOverBase generated with +// for (int base = 2; base < 37; ++base) { +// absl::int128 max = std::numeric_limits<absl::int128>::max(); +// auto result = max / base; +// std::cout << "\tMakeInt128(" << absl::Int128High64(result) << ", " +// << absl::Int128Low64(result) << "u),\n"; +// } +// See https://godbolt.org/z/7djYWz +// +// int128& operator/=(int128) is not constexpr, so hardcode the resulting array +// to avoid a static initializer. +template<> +const int128 LookupTables<int128>::kVmaxOverBase[] = { + 0, + 0, + MakeInt128(4611686018427387903, 18446744073709551615u), + MakeInt128(3074457345618258602, 12297829382473034410u), + MakeInt128(2305843009213693951, 18446744073709551615u), + MakeInt128(1844674407370955161, 11068046444225730969u), + MakeInt128(1537228672809129301, 6148914691236517205u), + MakeInt128(1317624576693539401, 2635249153387078802u), + MakeInt128(1152921504606846975, 18446744073709551615u), + MakeInt128(1024819115206086200, 16397105843297379214u), + MakeInt128(922337203685477580, 14757395258967641292u), + MakeInt128(838488366986797800, 13415813871788764811u), + MakeInt128(768614336404564650, 12297829382473034410u), + MakeInt128(709490156681136600, 11351842506898185609u), + MakeInt128(658812288346769700, 10540996613548315209u), + MakeInt128(614891469123651720, 9838263505978427528u), + MakeInt128(576460752303423487, 18446744073709551615u), + MakeInt128(542551296285575047, 9765923333140350855u), + MakeInt128(512409557603043100, 8198552921648689607u), + MakeInt128(485440633518672410, 17475862806672206794u), + MakeInt128(461168601842738790, 7378697629483820646u), + MakeInt128(439208192231179800, 7027331075698876806u), + MakeInt128(419244183493398900, 6707906935894382405u), + MakeInt128(401016175515425035, 2406097053092550210u), + MakeInt128(384307168202282325, 6148914691236517205u), + MakeInt128(368934881474191032, 5902958103587056517u), + MakeInt128(354745078340568300, 5675921253449092804u), + MakeInt128(341606371735362066, 17763531330238827482u), + MakeInt128(329406144173384850, 5270498306774157604u), + MakeInt128(318047311615681924, 7633135478776366185u), + MakeInt128(307445734561825860, 4919131752989213764u), + MakeInt128(297528130221121800, 4760450083537948804u), + MakeInt128(288230376151711743, 18446744073709551615u), + MakeInt128(279496122328932600, 4471937957262921603u), + MakeInt128(271275648142787523, 14106333703424951235u), + MakeInt128(263524915338707880, 4216398645419326083u), + MakeInt128(256204778801521550, 4099276460824344803u), +}; + +// This kVminOverBase generated with +// for (int base = 2; base < 37; ++base) { +// absl::int128 min = std::numeric_limits<absl::int128>::min(); +// auto result = min / base; +// std::cout << "\tMakeInt128(" << absl::Int128High64(result) << ", " +// << absl::Int128Low64(result) << "u),\n"; +// } +// +// See https://godbolt.org/z/7djYWz +// +// int128& operator/=(int128) is not constexpr, so hardcode the resulting array +// to avoid a static initializer. +template<> +const int128 LookupTables<int128>::kVminOverBase[] = { + 0, + 0, + MakeInt128(-4611686018427387904, 0u), + MakeInt128(-3074457345618258603, 6148914691236517206u), + MakeInt128(-2305843009213693952, 0u), + MakeInt128(-1844674407370955162, 7378697629483820647u), + MakeInt128(-1537228672809129302, 12297829382473034411u), + MakeInt128(-1317624576693539402, 15811494920322472814u), + MakeInt128(-1152921504606846976, 0u), + MakeInt128(-1024819115206086201, 2049638230412172402u), + MakeInt128(-922337203685477581, 3689348814741910324u), + MakeInt128(-838488366986797801, 5030930201920786805u), + MakeInt128(-768614336404564651, 6148914691236517206u), + MakeInt128(-709490156681136601, 7094901566811366007u), + MakeInt128(-658812288346769701, 7905747460161236407u), + MakeInt128(-614891469123651721, 8608480567731124088u), + MakeInt128(-576460752303423488, 0u), + MakeInt128(-542551296285575048, 8680820740569200761u), + MakeInt128(-512409557603043101, 10248191152060862009u), + MakeInt128(-485440633518672411, 970881267037344822u), + MakeInt128(-461168601842738791, 11068046444225730970u), + MakeInt128(-439208192231179801, 11419412998010674810u), + MakeInt128(-419244183493398901, 11738837137815169211u), + MakeInt128(-401016175515425036, 16040647020617001406u), + MakeInt128(-384307168202282326, 12297829382473034411u), + MakeInt128(-368934881474191033, 12543785970122495099u), + MakeInt128(-354745078340568301, 12770822820260458812u), + MakeInt128(-341606371735362067, 683212743470724134u), + MakeInt128(-329406144173384851, 13176245766935394012u), + MakeInt128(-318047311615681925, 10813608594933185431u), + MakeInt128(-307445734561825861, 13527612320720337852u), + MakeInt128(-297528130221121801, 13686293990171602812u), + MakeInt128(-288230376151711744, 0u), + MakeInt128(-279496122328932601, 13974806116446630013u), + MakeInt128(-271275648142787524, 4340410370284600381u), + MakeInt128(-263524915338707881, 14230345428290225533u), + MakeInt128(-256204778801521551, 14347467612885206813u), +}; + template <typename IntType> const IntType LookupTables<IntType>::kVmaxOverBase[] = X_OVER_BASE_INITIALIZER(std::numeric_limits<IntType>::max()); @@ -948,6 +1072,10 @@ bool safe_strto64_base(absl::string_view text, int64_t* value, int base) { return safe_int_internal<int64_t>(text, value, base); } +bool safe_strto128_base(absl::string_view text, int128* value, int base) { + return safe_int_internal<absl::int128>(text, value, base); +} + bool safe_strtou32_base(absl::string_view text, uint32_t* value, int base) { return safe_uint_internal<uint32_t>(text, value, base); } |