switch from custom stringFormat to fmtlib

The latter helps to avoid wrong format errors and is simpler to use.
Will be replaced by std::format once C++20 becomes mandatory.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

.github/workflows/codeql-analysis.yml

@@ -37,11 +37,11 @@ jobs:
     steps:
     - name: Checkout repository
       uses: actions/checkout@v4
-      
+
     - name: Install dependencies
       run: |
         sudo apt-get update
-        sudo apt-get install -y libexpat1-dev zlib1g-dev libbrotli-dev libinih-dev
+        sudo apt-get install -y libfmt-dev libexpat1-dev zlib1g-dev libbrotli-dev libinih-dev
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/on_PR_mac_matrix.yml

@@ -27,6 +27,7 @@ jobs:
         run: |
           brew install ninja
           brew install inih
+          brew install fmt
           brew install googletest
 
       - name: Build

.github/workflows/on_PR_mac_special_builds.yml

@@ -22,6 +22,7 @@ jobs:
         run: |
           brew install ninja
           brew install inih
+          brew install fmt
           brew install googletest
 
       - name: Build

.github/workflows/on_PR_meson.yaml

@@ -115,6 +115,7 @@ jobs:
             cc:p
             cmake:p
             curl:p
+            fmt:p
             gtest:p
             libinih:p
             meson:p
@@ -126,6 +127,34 @@ jobs:
           meson setup "${{github.workspace}}/build" -Dauto_features=${{matrix.deps}} -Dwarning_level=3 -Dcpp_std=c++20
           meson compile -C "${{github.workspace}}/build" --verbose
           meson test -C "${{github.workspace}}/build" --verbose
+  Cygwin:
+    runs-on: windows-latest
+    strategy:
+      matrix:
+        deps: ['enabled', 'disabled']
+        platform: ['x86', 'x86_64']
+    name: Cygwin-${{matrix.platform}}-deps=${{matrix.deps}}
+    defaults:
+      run:
+        shell: C:\cygwin\bin\bash.exe --noprofile --norc -o igncr -eo pipefail '{0}'
+    steps:
+      - uses: actions/checkout@v4
+      - uses: cygwin/cygwin-install-action@v4
+        with:
+          platform: ${{matrix.platform}}
+          packages: :>
+            cmake
+            gcc-g++
+            meson
+            ninja
+            pkg-config
+            python3
+            libiconv-devel
+      - name: Compile and Test
+        run: |
+          meson setup build -Dauto_features=${{matrix.deps}} -Dwarning_level=3 -Dcpp_std=c++20
+          meson compile -C build --verbose
+          meson test -C build --verbose
   MacOS:
     runs-on: macos-latest
     name: macOS-deps=${{matrix.deps}}
@@ -137,7 +166,7 @@ jobs:
 
       - name: Install packages
         run: |
-          brew install curl brotli inih expat googletest
+          brew install fmt curl brotli inih expat googletest
           python3 -m pip install meson==0.54.1 ninja
 
       - name: Compile and Test
@@ -154,7 +183,7 @@ jobs:
         uses: vmactions/freebsd-vm@v1
         with:
           prepare: |
-            pkg install -y cmake curl ninja meson gettext pkgconf googletest expat inih brotli
+            pkg install -y cmake curl ninja meson gettext pkgconf googletest expat inih brotli libfmt
           run: |
             meson setup "${{github.workspace}}/build" -Dwarning_level=3 -Dcpp_std=c++20
             meson compile -C "${{github.workspace}}/build" --verbose

.github/workflows/on_PR_windows_matrix.yml

@@ -116,6 +116,7 @@ jobs:
             libiconv:p
             libinih:p
             zlib:p
+            fmt:p
 
       - name: Build
         run: |
@@ -131,56 +132,3 @@ jobs:
       - name: Test
         run: |
           ctest --test-dir build --output-on-failure
-
-  cygwin:
-    runs-on: windows-latest
-    strategy:
-      fail-fast: false
-      matrix:
-        build_type: [Release]
-        shared_libraries: [ON]
-        platform: [x86_64]
-    name: Cygwin ${{matrix.platform}} - BuildType:${{matrix.build_type}} - SHARED:${{matrix.shared_libraries}}
-    env:
-      SHELLOPTS: igncr
-    defaults:
-      run:
-        shell: C:\cygwin\bin\bash.exe -eo pipefail '{0}'
-    steps:
-      # Make sure we don't check out scripts using Windows CRLF line endings
-      - run: git config --global core.autocrlf input
-        shell: pwsh
-      - uses: actions/checkout@v4
-
-      - name: Set up Cygwin
-        uses: cygwin/cygwin-install-action@v4
-        with:
-          platform: ${{matrix.platform}}
-          packages: >-
-            gcc-g++
-            cmake
-            ninja
-            pkg-config
-            python3
-            libbrotli-devel
-            libcurl-devel
-            libexpat-devel
-            libiconv-devel
-            libinih-devel
-            zlib-devel
-
-      - name: Build
-        run: |
-          cmake --preset base_windows \
-            -DCMAKE_BUILD_TYPE=${{matrix.build_type}} \
-            -DBUILD_SHARED_LIBS=${{matrix.shared_libraries}} \
-            -DCONAN_AUTO_INSTALL=OFF \
-            -DEXIV2_BUILD_SAMPLES=OFF \
-            -DEXIV2_BUILD_UNIT_TESTS=OFF \
-            -DEXIV2_TEAM_WARNINGS_AS_ERRORS=OFF \
-            -S . -B build && \
-          cmake --build build --parallel
-
-      - name: Test
-        run: |
-          ctest --test-dir build --output-on-failure

.github/workflows/on_push_BasicWinLinMac.yml

@@ -93,6 +93,7 @@ jobs:
         run: |
           brew install ninja
           brew install inih
+          brew install fmt
           brew install googletest
 
       - name: build and compile

CMakeLists.txt

@@ -91,6 +91,11 @@ endif()
 
 include_directories(${CMAKE_BINARY_DIR}) # Make the exv_conf.h file visible for the full project
 
+check_cxx_symbol_exists(__cpp_lib_format "format" HAVE_STD_FORMAT)
+if(NOT HAVE_STD_FORMAT)
+  find_package(fmt REQUIRED)
+endif()
+
 if(EXIV2_ENABLE_XMP)
   add_subdirectory(xmpsdk)
 endif()

ci/install_dependencies.sh

@@ -41,46 +41,46 @@ distro_id=$(grep '^ID=' /etc/os-release|awk -F = '{print $2}'|sed 's/\"//g')
 
 case "$distro_id" in
     'fedora')
-        dnf -y --refresh install gcc-c++ clang cmake ninja-build expat-devel zlib-devel brotli-devel libssh-devel libcurl-devel gmock-devel glibc-langpack-en inih-devel
+        dnf -y --refresh install gcc-c++ clang cmake ninja-build expat-devel zlib-devel brotli-devel libssh-devel libcurl-devel gmock-devel glibc-langpack-en inih-devel fmt-devel
         ;;
 
     'debian')
         apt-get update
-        apt-get install -y cmake ninja-build g++ clang libexpat1-dev zlib1g-dev libbrotli-dev libssh-dev libcurl4-openssl-dev libgmock-dev libxml2-utils libinih-dev
+        apt-get install -y cmake ninja-build g++ clang libexpat1-dev zlib1g-dev libbrotli-dev libssh-dev libcurl4-openssl-dev libgmock-dev libxml2-utils libinih-dev libfmt-dev
         # debian_build_gtest
         ;;
 
     'arch')
         pacman --noconfirm -Syu
-        pacman --noconfirm --needed -S gcc clang cmake ninja expat zlib brotli libssh curl gtest libinih
+        pacman --noconfirm --needed -S gcc clang cmake ninja expat zlib brotli libssh curl gtest libinih fmt
         ;;
 
     'ubuntu')
         apt-get update
-        apt-get install -y cmake ninja-build g++ clang libexpat1-dev zlib1g-dev libbrotli-dev libssh-dev libcurl4-openssl-dev libgmock-dev libxml2-utils libinih-dev
+        apt-get install -y cmake ninja-build g++ clang libexpat1-dev zlib1g-dev libbrotli-dev libssh-dev libcurl4-openssl-dev libgmock-dev libxml2-utils libinih-dev libfmt-dev
         # debian_build_gtest
         ;;
 
     'alpine')
         apk update
-        apk add gcc g++ clang cmake samurai expat-dev zlib-dev brotli-dev libssh-dev curl-dev gtest gtest-dev gmock libintl gettext-dev libxml2-utils inih-dev inih-inireader-dev
+        apk add gcc g++ clang cmake samurai expat-dev zlib-dev brotli-dev libssh-dev curl-dev gtest gtest-dev gmock libintl gettext-dev libxml2-utils inih-dev inih-inireader-dev fmt-dev
         ;;
 
     'rhel')
         dnf clean all
-        dnf -y install gcc-c++ clang cmake ninja-build expat-devel zlib-devel brotli-devel libssh-devel libcurl-devel inih-devel
+        dnf -y install gcc-c++ clang cmake ninja-build expat-devel zlib-devel brotli-devel libssh-devel libcurl-devel inih-devel fmt-devel
         ;;
 
     'centos')
         dnf clean all
-        dnf -y install gcc-c++ clang cmake expat-devel zlib-devel brotli-devel libssh-devel libcurl-devel git
+        dnf -y install gcc-c++ clang cmake expat-devel zlib-devel brotli-devel libssh-devel libcurl-devel git fmt-devel
         dnf -y --enablerepo=crb install ninja-build meson
         centos_build_inih
         ;;
 
     'opensuse-tumbleweed')
         zypper --non-interactive refresh
-        zypper --non-interactive install gcc-c++ clang cmake ninja libexpat-devel zlib-devel libbrotli-devel libssh-devel libcurl-devel gmock libxml2-tools libinih-devel
+        zypper --non-interactive install gcc-c++ clang cmake ninja libexpat-devel zlib-devel libbrotli-devel libssh-devel libcurl-devel gmock libxml2-tools libinih-devel libfmt-devel
         ;;
     *)
         echo "Sorry, no predefined dependencies for your distribution $distro_id exist yet"

conanfile.py

@@ -27,6 +27,8 @@ def requirements(self):
 
         self.requires('inih/55')
 
+        self.requires('fmt/10.1.1')
+
         if self.options.webready:
             self.requires('libcurl/7.85.0')
 

meson.build

@@ -54,6 +54,10 @@ deps = []
 deps += cpp.find_library('ws2_32', required: host_machine.system() == 'windows')
 deps += cpp.find_library('procstat', required: host_machine.system() == 'freebsd')
 
+if not cpp.has_header_symbol('format', '__cpp_lib_format')
+  deps += dependency('fmt')
+endif
+
 if cpp.get_argument_syntax() == 'gcc' and cpp.version().version_compare('<9')
   if host_machine.system() == 'linux' and cpp.get_define('_LIBCPP_VERSION', prefix: '#include <new>') == ''
     deps += cpp.find_library('stdc++fs')

src/CMakeLists.txt

@@ -250,6 +250,12 @@ else()
   target_link_libraries(exiv2lib PRIVATE psapi ws2_32 shell32)
 endif()
 
+if(NOT HAVE_STD_FORMAT)
+  target_link_libraries(exiv2lib PRIVATE fmt::fmt)
+  target_link_libraries(exiv2lib_int PRIVATE fmt::fmt)
+  list(APPEND requires_private_list "fmt")
+endif()
+
 if(EXIV2_ENABLE_PNG)
   target_link_libraries(exiv2lib PRIVATE ZLIB::ZLIB)
   list(APPEND requires_private_list "zlib")

src/bmffimage.cpp

@@ -81,7 +81,7 @@ bool enableBMFF(bool enable) {
 }
 
 std::string Iloc::toString() const {
-  return Internal::stringFormat("ID = %u from,length = %u,%u", ID_, start_, length_);
+  return stringFormat("ID = {} from,length = {},{}", ID_, start_, length_);
 }
 
 BmffImage::BmffImage(BasicIo::UniquePtr io, bool /* create */) :
@@ -269,7 +269,7 @@ uint64_t BmffImage::boxHandler(std::ostream& out /* = std::cout*/, Exiv2::PrintS
   if (bTrace) {
     bLF = true;
     out << Internal::indent(depth) << "Exiv2::BmffImage::boxHandler: " << toAscii(box_type)
-        << Internal::stringFormat(" %8zd->%" PRIu64 " ", address, box_length);
+        << stringFormat(" {:8}->{} ", address, box_length);
   }
 
   if (box_length == 1) {
@@ -366,7 +366,7 @@ uint64_t BmffImage::boxHandler(std::ostream& out /* = std::cout*/, Exiv2::PrintS
         id = " *** XMP ***";
       }
       if (bTrace) {
-        out << Internal::stringFormat("ID = %3d ", ID) << name << " " << id;
+        out << stringFormat("ID = {:3} {} {}", ID, name, id);
       }
     } break;
 
@@ -444,7 +444,7 @@ uint64_t BmffImage::boxHandler(std::ostream& out /* = std::cout*/, Exiv2::PrintS
           uint32_t ldata = data.read_uint32(skip + step - 4, endian_);
           if (bTrace) {
             out << Internal::indent(depth)
-                << Internal::stringFormat("%8zd | %8zd |   ID | %4u | %6u,%6u", address + skip, step, ID, offset, ldata)
+                << stringFormat("{:8} | {:8} |   ID | {:4} | {:6},{:6}", address + skip, step, ID, offset, ldata)
                 << std::endl;
           }
           // save data for post-processing in meta box
@@ -463,7 +463,7 @@ uint64_t BmffImage::boxHandler(std::ostream& out /* = std::cout*/, Exiv2::PrintS
       uint32_t height = data.read_uint32(skip, endian_);
       skip += 4;
       if (bTrace) {
-        out << "pixelWidth_, pixelHeight_ = " << Internal::stringFormat("%d, %d", width, height);
+        out << stringFormat("pixelWidth_, pixelHeight_ = {}, {}", width, height);
       }
       // HEIC files can have multiple ispe records
       // Store largest width/height
@@ -678,8 +678,8 @@ void BmffImage::parseCr3Preview(const DataBuf& data, std::ostream& out, bool bTr
     return "application/octet-stream";
   }();
   if (bTrace) {
-    out << Internal::stringFormat("width,height,size = %zu,%zu,%zu", nativePreview.width_, nativePreview.height_,
-                                  nativePreview.size_);
+    out << stringFormat("width,height,size = {},{},{}", nativePreview.width_, nativePreview.height_,
+                        nativePreview.size_);
   }
   nativePreviews_.push_back(std::move(nativePreview));
 }

src/futils.cpp

@@ -373,7 +373,7 @@ std::string getProcessPath() {
       return "unknown";  // pathbuf not big enough
     auto path = fs::path(pathbuf);
 #elif defined(__sun__)
-    auto path = fs::read_symlink(Internal::stringFormat("/proc/%d/path/a.out", getpid()));
+    auto path = fs::read_symlink(stringFormat("/proc/%d/path/a.out", getpid()));
 #elif defined(__unix__)
     auto path = fs::read_symlink("/proc/self/exe");
 #endif

src/image.cpp

@@ -350,8 +350,7 @@ void Image::printIFDStructure(BasicIo& io, std::ostream& out, Exiv2::PrintStruct
       throw Error(ErrorCode::kerTiffDirectoryTooLarge);
 
     if (bFirst && bPrint) {
-      out << Internal::indent(depth) << Internal::stringFormat("STRUCTURE OF TIFF FILE (%c%c): ", c, c) << io.path()
-          << std::endl;
+      out << Internal::indent(depth) << stringFormat("STRUCTURE OF TIFF FILE ({}{}): {}", c, c, io.path()) << std::endl;
     }
 
     // Read the dictionary
@@ -435,11 +434,11 @@ void Image::printIFDStructure(BasicIo& io, std::ostream& out, Exiv2::PrintStruct
 
       if (bPrint) {
         const size_t address = start + 2 + i * 12;
-        const std::string offsetString = bOffsetIsPointer ? Internal::stringFormat("%10u", offset) : "";
+        const std::string offsetString = bOffsetIsPointer ? stringFormat("{:9}", offset) : "";
 
         out << Internal::indent(depth)
-            << Internal::stringFormat("%8zu | %#06x %-28s |%10s |%9u |%10s | ", address, tag, tagName(tag).c_str(),
-                                      typeName(type), count, offsetString.c_str());
+            << stringFormat("{:8} | {:#06x} {:<28} | {:>9} | {:>8} | {:9} | ", address, tag, tagName(tag).c_str(),
+                            typeName(type), count, offsetString);
         if (isShortType(type)) {
           for (size_t k = 0; k < kount; k++) {
             out << sp << byteSwap2(buf, k * size, bSwap);

src/image_int.cpp

@@ -9,32 +9,6 @@
 #include <vector>
 
 namespace Exiv2::Internal {
-std::string stringFormat(const char* format, ...) {
-  std::string result;
-  std::vector<char> buffer;
-  size_t need = std::strlen(format) * 8;  // initial guess
-  int rc = -1;
-
-  // vsnprintf writes at most size (2nd parameter) bytes (including \0)
-  //           returns the number of bytes required for the formatted string excluding \0
-  // the following loop goes through:
-  // one iteration (if 'need' was large enough for the for formatted string)
-  // or two iterations (after the first call to vsnprintf we know the required length)
-  do {
-    buffer.resize(need + 1);
-    va_list args;            // variable arg list
-    va_start(args, format);  // args start after format
-    rc = vsnprintf(buffer.data(), buffer.size(), format, args);
-    va_end(args);  // free the args
-    if (rc > 0)
-      need = static_cast<size_t>(rc);
-  } while (buffer.size() <= need);
-
-  if (rc > 0)
-    result = std::string(buffer.data(), need);
-  return result;
-}
-
 [[nodiscard]] std::string indent(size_t i) {
   return std::string(2 * i, ' ');
 }