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1#ifndef BENCHMARK_REGISTER_H2#define BENCHMARK_REGISTER_H3 4#include <algorithm>5#include <limits>6#include <vector>7 8#include "check.h"9 10namespace benchmark {11namespace internal {12 13// Append the powers of 'mult' in the closed interval [lo, hi].14// Returns iterator to the start of the inserted range.15template <typename T>16typename std::vector<T>::iterator AddPowers(std::vector<T>* dst, T lo, T hi,17 int mult) {18 BM_CHECK_GE(lo, 0);19 BM_CHECK_GE(hi, lo);20 BM_CHECK_GE(mult, 2);21 22 const size_t start_offset = dst->size();23 24 static const T kmax = std::numeric_limits<T>::max();25 26 // Space out the values in multiples of "mult"27 for (T i = static_cast<T>(1); i <= hi; i *= static_cast<T>(mult)) {28 if (i >= lo) {29 dst->push_back(i);30 }31 // Break the loop here since multiplying by32 // 'mult' would move outside of the range of T33 if (i > kmax / mult) break;34 }35 36 return dst->begin() + static_cast<int>(start_offset);37}38 39template <typename T>40void AddNegatedPowers(std::vector<T>* dst, T lo, T hi, int mult) {41 // We negate lo and hi so we require that they cannot be equal to 'min'.42 BM_CHECK_GT(lo, std::numeric_limits<T>::min());43 BM_CHECK_GT(hi, std::numeric_limits<T>::min());44 BM_CHECK_GE(hi, lo);45 BM_CHECK_LE(hi, 0);46 47 // Add positive powers, then negate and reverse.48 // Casts necessary since small integers get promoted49 // to 'int' when negating.50 const auto lo_complement = static_cast<T>(-lo);51 const auto hi_complement = static_cast<T>(-hi);52 53 const auto it = AddPowers(dst, hi_complement, lo_complement, mult);54 55 std::for_each(it, dst->end(), [](T& t) { t *= -1; });56 std::reverse(it, dst->end());57}58 59template <typename T>60void AddRange(std::vector<T>* dst, T lo, T hi, int mult) {61 static_assert(std::is_integral<T>::value && std::is_signed<T>::value,62 "Args type must be a signed integer");63 64 BM_CHECK_GE(hi, lo);65 BM_CHECK_GE(mult, 2);66 67 // Add "lo"68 dst->push_back(lo);69 70 // Handle lo == hi as a special case, so we then know71 // lo < hi and so it is safe to add 1 to lo and subtract 172 // from hi without falling outside of the range of T.73 if (lo == hi) return;74 75 // Ensure that lo_inner <= hi_inner below.76 if (lo + 1 == hi) {77 dst->push_back(hi);78 return;79 }80 81 // Add all powers of 'mult' in the range [lo+1, hi-1] (inclusive).82 const auto lo_inner = static_cast<T>(lo + 1);83 const auto hi_inner = static_cast<T>(hi - 1);84 85 // Insert negative values86 if (lo_inner < 0) {87 AddNegatedPowers(dst, lo_inner, std::min(hi_inner, T{-1}), mult);88 }89 90 // Treat 0 as a special case (see discussion on #762).91 if (lo < 0 && hi >= 0) {92 dst->push_back(0);93 }94 95 // Insert positive values96 if (hi_inner > 0) {97 AddPowers(dst, std::max(lo_inner, T{1}), hi_inner, mult);98 }99 100 // Add "hi" (if different from last value).101 if (hi != dst->back()) {102 dst->push_back(hi);103 }104}105 106} // namespace internal107} // namespace benchmark108 109#endif // BENCHMARK_REGISTER_H110