locale-aware byte size formatter

Char-based number formatting (using std::stringstream)
is broken for locales with non-ascii thousand separator
(at least with gcc 8.3.0), for that reason, we should
provide custom locale aware number-to-string conversion
for float numbers and use it in ByteSizeToString utility.

Tests/src/StringUtils.cpp

@@ -308,8 +308,21 @@ TEST_CASE("Local aware number to string")
 {
   osmscout::Locale locale;
   locale.SetThousandsSeparator(" ");
+  locale.SetDecimalSeparator(".");
   REQUIRE(osmscout::NumberToString(1002030, locale) == "1 002 030");
   REQUIRE(osmscout::NumberToString(-1002030, locale) == "-1 002 030");
+
+  REQUIRE(osmscout::FloatToString(-1002030.123456, locale, 6) == "-1 002 030.123 456");
+  REQUIRE(osmscout::FloatToString(-1002030.125, locale, 2) == "-1 002 030.13");
+}
+
+TEST_CASE("Byte size to string")
+{
+  osmscout::Locale locale;
+  locale.SetThousandsSeparator("'");
+  locale.SetDecimalSeparator(",");
+  locale.SetUnitsSeparator(" ");
+  REQUIRE(osmscout::ByteSizeToString(1063256064.0, locale) == "1'014,0 MiB");
 }
 
 TEST_CASE("Trim string")

libosmscout-client/src/osmscoutclient/MapManager.cpp

@@ -48,7 +48,7 @@ CancelableFuture<bool> MapManager::LookupDatabases()
       // https://en.cppreference.com/w/cpp/filesystem/is_directory
       // https://en.cppreference.com/w/cpp/filesystem/status
       if (!std::filesystem::exists(lookupDir) || !std::filesystem::is_directory(lookupDir)) {
-        osmscout::log.Warn() << "Lookup dir" << lookupDir.string() << "doesn't exist or isn't a directory";
+        osmscout::log.Warn() << "Lookup dir " << lookupDir.string() << " doesn't exist or isn't a directory";
         continue;
       }
 

libosmscout/include/osmscout/util/String.h

@@ -74,10 +74,20 @@ namespace osmscout {
    *
    * @param value
    * @param locale
-   * @return
+   * @return UTF-8 string
    */
   extern OSMSCOUT_API std::string NumberToString(long value, const Locale &locale);
 
+  /**
+   * Returns locale-aware string representation of number
+   *
+   * @param value
+   * @param locale
+   * @param precision
+   * @return UTF-8 string
+   */
+  extern OSMSCOUT_API std::string FloatToString(double value, const Locale &locale, uint32_t precision = 3);
+
   /**
    * \ingroup Util
    * Returns the numerical value of the given character, if the character
@@ -403,9 +413,13 @@ namespace osmscout {
   /**
    * \ingroup Util
    *
+   * Prints byte size with short, human readable form by ISO/IEC 80000 standard.
+   * It means that KiB stands for 1024 bytes, MiB for 1024^2, GiB 1024^3...
+   *
+   * Returned string is locale aware, UTF-8 encoded
    */
-  extern OSMSCOUT_API std::string ByteSizeToString(FileOffset size);
-  extern OSMSCOUT_API std::string ByteSizeToString(double size);
+  extern OSMSCOUT_API std::string ByteSizeToString(FileOffset size, const Locale &locale = Locale::ByEnvironment());
+  extern OSMSCOUT_API std::string ByteSizeToString(double size, const Locale &locale = Locale::ByEnvironment());
 
   /**
    * \ingroup Util

libosmscout/src/osmscout/util/String.cpp

@@ -196,7 +196,8 @@ namespace osmscout {
   std::string NumberToString(long value, const Locale &locale)
   {
     std::stringstream ss;
-    if (std::abs(value) < 1000 || locale.GetThousandsSeparator().empty()){
+    ss.imbue(std::locale("C"));
+    if (locale.GetThousandsSeparator().empty()){
       ss << value;
     }else{
       long mag=1000;
@@ -214,6 +215,25 @@ namespace osmscout {
     return ss.str();
   }
 
+  extern OSMSCOUT_API std::string FloatToString(double value, const Locale &locale, uint_2 precision)
+  {
+    std::stringstream ss;
+    ss << NumberToString(static_cast<long>(value), locale);
+
+    if (precision > 0) {
+      ss << locale.GetDecimalSeparator();
+      double fractionNum = std::abs(value - std::ceil(value));
+      std::string fraction = NumberToString(std::round(fractionNum * std::pow(10, precision)), Locale());
+      for (size_t i = 0; i < fraction.size(); i++) {
+        if (i > 0 && i % 3 == 0 && i < fraction.size() - 1) {
+          ss << locale.GetThousandsSeparator();
+        }
+        ss << fraction[i];
+      }
+    }
+    return ss.str();
+  }
+
   bool GetDigitValue(char digit, size_t& result)
   {
     switch (digit) {
@@ -329,36 +349,32 @@ namespace osmscout {
     return wordCount;
   }
 
-  std::string ByteSizeToString(FileOffset value)
+  std::string ByteSizeToString(FileOffset value, const Locale &locale)
   {
-    return ByteSizeToString((double)value);
+    return ByteSizeToString(static_cast<double>(value), locale);
   }
 
-  std::string ByteSizeToString(double value)
+  std::string ByteSizeToString(double value, const Locale &locale)
   {
     std::stringstream buffer;
 
-    buffer.setf(std::ios::fixed);
-    buffer << std::setprecision(1);
-
     if (value<1.0 && value>-1) {
-      buffer << "0 B";
+      buffer << "0" << locale.GetUnitsSeparator() << "B";
     }
-    else if (ceil(value)>=1024.0*1024*1024*1024) {
-      buffer << value/(1024.0*1024*1024*1024) << " TiB";
+    else if (ceil(value)>=std::pow(1024.0, 4.0)) {
+      buffer << FloatToString(value/std::pow(1024.0, 4.0), locale, 1) << locale.GetUnitsSeparator()  << "TiB";
     }
-    else if (ceil(value)>=1024.0*1024*1024) {
-      buffer << value/(1024.0*1024*1024) << " GiB";
+    else if (ceil(value)>=std::pow(1024.0, 3.0)) {
+      buffer << FloatToString(value/std::pow(1024.0, 3.0), locale, 1) << locale.GetUnitsSeparator() << "GiB";
     }
-    else if (ceil(value)>=1024.0*1024) {
-      buffer << value/(1024.0*1024) << " MiB";
+    else if (ceil(value)>=std::pow(1024.0, 2.0)) {
+      buffer << FloatToString(value/std::pow(1024.0, 2.0), locale, 1) << locale.GetUnitsSeparator() << "MiB";
     }
     else if (ceil(value)>=1024.0) {
-      buffer << value/1024.0 << " KiB";
+      buffer << FloatToString(value/1024.0, locale, 1) << locale.GetUnitsSeparator() << "KiB";
     }
     else {
-      buffer << std::setprecision(0);
-      buffer << value << " B";
+      buffer << FloatToString(value, locale, 0) << locale.GetUnitsSeparator() << "B";
     }
 
     return buffer.str();