switch from custom stringFormat to fmtlib

[neheb]

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

[ghost]

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[codecov]

Codecov Report

Attention: Patch coverage is 36.36364% with 35 lines in your changes are missing coverage. Please review.

Project coverage is 64.57%. Comparing base (77915ad) to head (a0aa4a7).
Report is 11 commits behind head on main.

❗ Current head a0aa4a7 differs from pull request most recent head 51fd65b. Consider uploading reports for the commit 51fd65b to get more accurate results

Files	Patch %	Lines
src/rafimage.cpp	0.00%	26 Missing ⚠️
src/basicio.cpp	14.28%	6 Missing ⚠️
src/bmffimage.cpp	71.42%	2 Missing ⚠️
src/image.cpp	75.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2769      +/-   ##
==========================================
- Coverage   64.62%   64.57%   -0.05%     
==========================================
  Files         104      104              
  Lines       22239    22155      -84     
  Branches    10911    10849      -62     
==========================================
- Hits        14371    14306      -65     
+ Misses       5626     5610      -16     
+ Partials     2242     2239       -3     

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[kmilos]

How about we just wait for C++20 as min requirement and use std::format straight away? Or code it in a way to use std::format if using C++20 so there is one less dependency?

[neheb]

Rebased.

[neheb]

Rebased.

[kmilos]

@neheb I think I managed to install GCC 13 for the Cygwin job so this can finally proceed.

[neheb]

Hmm? Not sure what you mean by GCC 13 on Cygwin needed.

[kmilos]

Hmm? Not sure what you mean by GCC 13 on Cygwin needed.

It's been a while, heh? 😉 There is no fmt package on Cygwin, and only GCC (libstdc++) 13 onwards has this feature.

[kevinbackhouse]

I think the CIFuzz error might fix itself after this is merged. My guess is that OSS-Fuzz is running ci/install_dependencies.sh from the main branch, so the fmt package isn't installed. If something goes wrong, we can do a follow-up PR to fix it.

[neheb]

hmmm CMAKE_CXX_STANDARD is not being overwritten.

[kmilos]

hmmm CMAKE_CXX_STANDARD is not being overwritten

Looks like it gets reset back to 17 at least here and here:

exiv2/cmake/compilerFlags.cmake

Line 4 in cb6cbb1

set(CMAKE_CXX_STANDARD 17)

exiv2/cmake/FindFilesystem.cmake

Line 129 in cb6cbb1

set(CMAKE_CXX_STANDARD 17)

Those should probably be wrapped w/ if(NOT CMAKE_CXX_STANDARD)...?

[neheb]

good to go now.

[kmilos]

Ah, one last thing, but could be added in a separate PR: probably now also need to (conditionally) include fmt dependency in the CMake config file...