"Failed to read attribute" error message on Big Endian platform?

[s-trinh]

Describe the issue

   Error: Unable to parse EXR header from /root/visp-images/memorial/
  memorial_color_32bits.exr : Failed to read attribute.

when testing to read an EXR file on a Build on ubuntu20.04 s390x (Big Endian) platform.

To Reproduce
Steps to reproduce the behavior:

1. Compile TinyEXR with:

General configuration information for ViSP 3.5.1

  Version control:               unknown

  Platform:
    Timestamp:                   2023-03-11T17:14:14Z
    Host:                        Linux 5.15.0-1034-azure s390x
    CMake:                       3.16.3
    CMake generator:             Unix Makefiles
    CMake build tool:            /usr/bin/make
    Configuration:               Release

  System information:
    Number of CPU logical cores: 2
    Number of CPU physical cores: 2
    Total physical memory (in MiB): 6943
    OS name:                     Linux
    OS release:                  5.15.0-1034-azure
    OS version:                  #41~20.04.1-Ubuntu SMP Sat Feb 11 17:02:42 UTC 2023
    OS platform:                 s390x
    CPU name:                    Unknown P6 family
    Is the CPU 64-bit?           yes
    Does the CPU have FPU?       yes
    CPU optimization:

  C/C++:
    Built as dynamic libs?:      yes
    C++ Compiler:                /usr/bin/c++  (ver 9.4.0)
    C++ flags (Release):         -Wall -Wextra -fopenmp -std=c++17 -fvisibility=hidden -fPIC -O3 -DNDEBUG
    C++ flags (Debug):           -Wall -Wextra -fopenmp -std=c++17 -fvisibility=hidden -fPIC -g
    C Compiler:                  /usr/bin/cc
    C flags (Release):           -Wall -Wextra -fopenmp -std=c++17 -fvisibility=hidden -fPIC -O3 -DNDEBUG
    C flags (Debug):             -Wall -Wextra -fopenmp -std=c++17 -fvisibility=hidden -fPIC -g
    Linker flags (Release):
    Linker flags (Debug):
    Use cxx standard:            17

Version at: 3c8e0cb
2. Load EXR Image memorial_color_32bits.exr
3. See error:

EXR image read
Color
32-bits

/home/runner/work/visp/visp/modules/core/test/image-with-dataset/testIoEXR.cpp:88
...............................................................................

/home/runner/work/visp/visp/modules/core/test/image-with-dataset/testIoEXR.cpp:88: FAILED:
{Unknown expression after the reported line}
due to unexpected exception with message:
Error: Unable to parse EXR header from /root/visp-images/memorial/
memorial_color_32bits.exr : Failed to read attribute.

---

I suspect an issue with endianness since it occurs specifically on this platform: Build on ubuntu20.04 s390x (Big Endian).

Otherwise, did I miss checking something when reading the EXR file?
This is the code used.

Many thanks.

[syoyo]

[memorial_color_32bits.exr](https://github.com/lagadic/visp-images/blob/master/memorial/memorial_color_32bits.exr) can be correctly load in test_tinyexr example on x86_64, so the issue would be Endianness.

There was a Big Endian support in TinyEXR when I had a SPARC CPU(8~9 years ago!), but not maintained in recent years.

@s-trinh Something may be still missing to support Big Endian in recently added codes You may find an issue in ReadAttribute by dumping its content.

tinyexr/tinyexr.h

Line 1029 in 02310c7

static bool ReadAttribute(std::string *name, std::string *type,

Contribution of Big Endian support is much appreciated!
(PIZ decompression/compression support in Big Endian is also appreciated!

tinyexr/tinyexr.h

Line 3161 in 02310c7

#if !TINYEXR_LITTLE_ENDIAN

)

[s-trinh]

Thanks for your answer 👍
I will see what I could do.