From 5107f9d0b3be326aea462cc57c4e957e80051e77 Mon Sep 17 00:00:00 2001
From: Christoph Hasse <hassec@users.noreply.github.com>
Date: Thu, 28 Mar 2024 21:06:27 -0600
Subject: [PATCH] fix(lens): canon lens detecton should be independent of
 locale

---
 CMakeLists.txt      |  5 +++++
 src/canonmn_int.cpp | 27 +++++++++++++++++++++------
 2 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index cd339a6213..5984187e44 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -139,6 +139,11 @@ if(EXIV2_BUILD_EXIV2_COMMAND)
       WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}/tests
       COMMAND cmake -E env EXIV2_BINDIR=${CMAKE_RUNTIME_OUTPUT_DIRECTORY} ${Python3_EXECUTABLE} runner.py --verbose lens_tests
     )
+    add_test(
+      NAME lensTestsLocaleDE
+      WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}/tests
+      COMMAND cmake -E env LC_ALL=de_DE.UTF-8 EXIV2_BINDIR=${CMAKE_RUNTIME_OUTPUT_DIRECTORY} ${Python3_EXECUTABLE} runner.py --verbose lens_tests
+    )
     add_test(
       NAME tiffTests
       WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}/tests
diff --git a/src/canonmn_int.cpp b/src/canonmn_int.cpp
index 3de6946f6f..804e7b59b1 100644
--- a/src/canonmn_int.cpp
+++ b/src/canonmn_int.cpp
@@ -18,12 +18,12 @@
 #include "value.hpp"
 
 // + standard includes
+#include <charconv>
 #include <cmath>
 #include <iomanip>
 #include <regex>
 #include <sstream>
 #include <string>
-
 // *****************************************************************************
 // class member definitions
 namespace Exiv2::Internal {
@@ -2851,6 +2851,21 @@ std::ostream& printCsLensFFFF(std::ostream& os, const Value& value, const ExifDa
   return EXV_PRINT_TAG(canonCsLensType)(os, value, metadata);
 }
 
+float string_to_float(std::string const& str) {
+  float val{};
+  std::stringstream ss;
+  std::locale c_locale("C");
+  ss.imbue(c_locale);
+  ss << str;
+  ss >> val;
+
+  if (ss.fail()) {
+    throw Error(ErrorCode::kerErrorMessage, std::string("canonmn_int.cpp:string_to_float failed for: ") + str);
+  }
+
+  return val;
+}
+
 std::ostream& printCsLensTypeByMetadata(std::ostream& os, const Value& value, const ExifData* metadata) {
   if (!metadata || value.typeId() != unsignedShort || value.count() == 0)
     return os << value;
@@ -2914,13 +2929,13 @@ std::ostream& printCsLensTypeByMetadata(std::ostream& os, const Value& value, co
       throw Error(ErrorCode::kerErrorMessage, std::string("Lens regex didn't match for: ") + std::string(label));
     }
 
-    auto tc = base_match[5].length() > 0 ? std::stof(base_match[5].str()) : 1.f;
+    auto tc = base_match[5].length() > 0 ? string_to_float(base_match[5].str()) : 1.f;
 
-    auto flMax = static_cast<int>(std::stof(base_match[2].str()) * tc);
-    int flMin = base_match[1].length() > 0 ? static_cast<int>(std::stof(base_match[1].str()) * tc) : flMax;
+    auto flMax = static_cast<int>(string_to_float(base_match[2].str()) * tc);
+    int flMin = base_match[1].length() > 0 ? static_cast<int>(string_to_float(base_match[1].str()) * tc) : flMax;
 
-    auto aperMaxTele = std::stof(base_match[4].str()) * tc;
-    auto aperMaxShort = base_match[3].length() > 0 ? std::stof(base_match[3].str()) * tc : aperMaxTele;
+    auto aperMaxTele = string_to_float(base_match[4].str()) * tc;
+    auto aperMaxShort = base_match[3].length() > 0 ? string_to_float(base_match[3].str()) * tc : aperMaxTele;
 
     if (flMin != exifFlMin || flMax != exifFlMax || exifAperMax < (aperMaxShort - .1 * tc) ||
         exifAperMax > (aperMaxTele + .1 * tc)) {