Locale-independent to_double and from_double conversions.

GitOrigin-RevId: 997ec58422c4128857d395fa49c46ee0605afca9

td/telegram/cli.cpp

@@ -40,6 +40,7 @@
 #include <algorithm>
 #include <array>
 #include <atomic>
+#include <clocale>
 #include <cstdlib>
 #include <cstring>  // for strcmp
 #include <ctime>
@@ -2929,6 +2930,8 @@ void main(int argc, char **argv) {
   set_signal_handler(SignalType::Abort, fail_signal).ensure();
   td::Log::set_fatal_error_callback(on_fatal_error);
 
+  std::setlocale(LC_ALL, "fr-FR");
+
   CliLog cli_log;
   log_interface = &cli_log;
 

tdutils/td/utils/StringBuilder.cpp

@@ -6,7 +6,11 @@
 //
 #include "td/utils/StringBuilder.h"
 
+#include "td/utils/misc.h"
+
 #include <cstdio>
+#include <locale>
+#include <sstream>
 
 namespace td {
 
@@ -63,14 +67,24 @@ StringBuilder &StringBuilder::operator<<(double x) {
   if (unlikely(end_ptr_ < current_ptr_)) {
     return on_error();
   }
+
+  static TD_THREAD_LOCAL std::stringstream *ss;
+  if (init_thread_local<std::stringstream>(ss)) {
+    ss->imbue(std::locale::classic());
+  } else {
+    ss->str(std::string());
+    ss->clear();
+  }
+  *ss << x;
+
+  int len = narrow_cast<int>(static_cast<std::streamoff>(ss->tellp()));
   auto left = end_ptr_ + reserved_size - current_ptr_;
-  int len = std::snprintf(current_ptr_, left, "%lf", x);
   if (unlikely(len >= left)) {
     error_flag_ = true;
-    current_ptr_ += left - 1;
-  } else {
-    current_ptr_ += len;
+    len = left - 1;
   }
+  ss->read(current_ptr_, len);
+  current_ptr_ += len;
   return *this;
 }
 

tdutils/td/utils/misc.cpp

@@ -8,6 +8,8 @@
 
 #include <algorithm>
 #include <cstdlib>
+#include <locale>
+#include <sstream>
 
 namespace td {
 
@@ -57,7 +59,18 @@ string oneline(Slice str) {
 }
 
 double to_double(CSlice str) {
-  return std::atof(str.c_str());
+  static TD_THREAD_LOCAL std::stringstream *ss;
+  if (init_thread_local<std::stringstream>(ss)) {
+    ss->imbue(std::locale::classic());
+  } else {
+    ss->str(std::string());
+    ss->clear();
+  }
+  ss->write(str.begin(), narrow_cast<std::streamsize>(str.size()));
+
+  double result = 0.0;
+  *ss >> result;
+  return result;
 }
 
 }  // namespace td

tdutils/test/misc.cpp

@@ -14,9 +14,11 @@
 #include "td/utils/port/Stat.h"
 #include "td/utils/port/thread.h"
 #include "td/utils/Random.h"
+#include "td/utils/Slice.h"
 #include "td/utils/tests.h"
 
 #include <atomic>
+#include <clocale>
 #include <limits>
 
 using namespace td;
@@ -187,3 +189,35 @@ TEST(Misc, to_integer) {
   ASSERT_EQ(to_integer_safe<uint64>("12345678910111213").ok(), 12345678910111213ull);
   ASSERT_TRUE(to_integer_safe<uint64>("-12345678910111213").is_error());
 }
+
+static void test_to_double_one(CSlice str, Slice expected) {
+  auto result = PSTRING() << to_double(str);
+  if (expected != result) {
+    LOG(ERROR) << "To double conversion failed: have " << str << ", expected " << expected << ", parsed "
+               << to_double(str) << ", got " << result;
+  }
+}
+
+static void test_to_double() {
+  test_to_double_one("0", "0");
+  test_to_double_one("1", "1");
+  test_to_double_one("-10", "-10");
+  test_to_double_one("1.234", "1.234");
+  test_to_double_one("-1.234e2", "-123.4");
+  test_to_double_one("inf", "inf");
+  test_to_double_one("  inF  asdasd", "inf");
+  test_to_double_one("  inFasdasd", "0");
+  test_to_double_one("  NaN", "nan");
+  test_to_double_one("  12345678910111213141516171819  asdasd", "1.23457e+28");
+  test_to_double_one("1.234567891011121314E123", "1.23457e+123");
+  test_to_double_one("123456789", "1.23457e+08");
+  test_to_double_one("-1,234567891011121314E123", "-1");
+}
+
+TEST(Misc, to_double) {
+  test_to_double();
+  std::setlocale(LC_ALL, "fr-FR");
+  test_to_double();
+  std::setlocale(LC_ALL, "C");
+  test_to_double();
+}