mirror of
https://github.com/fastfloat/fast_float.git
synced 2025-12-07 01:06:48 +08:00
132 lines
3.9 KiB
C++
132 lines
3.9 KiB
C++
#include "fast_float/fast_float.h"
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#include <iostream>
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#include <random>
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#include <sstream>
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#include <vector>
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#if defined(__CYGWIN__) || defined(__MINGW32__) || defined(__MINGW64__) || defined(sun) || defined(__sun)
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// Anything at all that is related to cygwin, msys and so forth will
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// always use this fallback because we cannot rely on it behaving as normal
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// gcc.
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#include <locale>
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#include <sstream>
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// workaround for CYGWIN
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double cygwin_strtod_l(const char* start, char** end) {
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double d;
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std::stringstream ss;
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ss.imbue(std::locale::classic());
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ss << start;
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ss >> d;
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if(ss.fail()) { *end = nullptr; }
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if(ss.eof()) { ss.clear(); }
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auto nread = ss.tellg();
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*end = const_cast<char*>(start) + nread;
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return d;
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}
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float cygwin_strtof_l(const char* start, char** end) {
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float d;
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std::stringstream ss;
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ss.imbue(std::locale::classic());
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ss << start;
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ss >> d;
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if(ss.fail()) { *end = nullptr; }
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if(ss.eof()) { ss.clear(); }
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auto nread = ss.tellg();
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*end = const_cast<char*>(start) + nread;
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return d;
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}
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#endif
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std::pair<double, bool> strtod_from_string(const char *st) {
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double d;
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char *pr;
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#if defined(__CYGWIN__) || defined(__MINGW32__) || defined(__MINGW64__) || defined(sun) || defined(__sun)
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d = cygwin_strtod_l(st, &pr);
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#elif defined(_WIN32)
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static _locale_t c_locale = _create_locale(LC_ALL, "C");
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d = _strtod_l(st, &pr, c_locale);
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#else
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static locale_t c_locale = newlocale(LC_ALL_MASK, "C", NULL);
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d = strtod_l(st, &pr, c_locale);
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#endif
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if (st == pr) {
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std::cerr << "strtod_l could not parse '" << st << std::endl;
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return std::make_pair(0, false);
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}
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return std::make_pair(d, true);
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}
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std::pair<float, bool> strtof_from_string(char *st) {
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float d;
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char *pr;
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#if defined(__CYGWIN__) || defined(__MINGW32__) || defined(__MINGW64__) || defined(sun) || defined(__sun)
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d = cygwin_strtof_l(st, &pr);
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#elif defined(_WIN32)
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static _locale_t c_locale = _create_locale(LC_ALL, "C");
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d = _strtof_l(st, &pr, c_locale);
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#else
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static locale_t c_locale = newlocale(LC_ALL_MASK, "C", NULL);
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d = strtof_l(st, &pr, c_locale);
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#endif
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if (st == pr) {
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std::cerr << "strtof_l could not parse '" << st << std::endl;
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return std::make_pair(0.0f, false);
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}
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return std::make_pair(d, true);
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}
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bool tester() {
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std::random_device rd;
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std::mt19937 gen(rd());
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for (int q = 18; q <= 27; q++) {
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std::cout << "q = " << -q << std::endl;
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uint64_t power5 = 1;
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for (int k = 0; k < q; k++) {
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power5 *= 5;
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}
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uint64_t low_threshold = 0x20000000000000 / power5 + 1;
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uint64_t threshold = 0xFFFFFFFFFFFFFFFF / power5;
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std::uniform_int_distribution<uint64_t> dis(low_threshold, threshold);
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for (size_t i = 0; i < 10000; i++) {
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uint64_t mantissa = dis(gen) * power5;
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std::stringstream ss;
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ss << mantissa;
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ss << "e";
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ss << -q;
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std::string to_be_parsed = ss.str();
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std::pair<double, bool> expected_double =
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strtod_from_string(to_be_parsed.c_str());
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double result_value;
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auto result =
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fast_float::from_chars(to_be_parsed.data(), to_be_parsed.data() + to_be_parsed.size(), result_value);
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if (result.ec != std::errc()) {
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std::cout << to_be_parsed << std::endl;
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std::cerr << " I could not parse " << std::endl;
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return false;
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}
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if (result_value != expected_double.first) {
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std::cout << to_be_parsed << std::endl;
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std::cerr << std::hexfloat << result_value << std::endl;
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std::cerr << std::hexfloat << expected_double.first << std::endl;
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std::cerr << " Mismatch " << std::endl;
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return false;
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}
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}
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}
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return true;
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}
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int main() {
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if (tester()) {
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std::cout << std::endl;
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std::cout << "all ok" << std::endl;
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return EXIT_SUCCESS;
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}
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std::cerr << std::endl;
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std::cerr << "errors were encountered" << std::endl;
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return EXIT_FAILURE;
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}
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