MemoryError on ppc64

[opoplawski]

What did you do?

Trying to build Fedora package for EPEL7, 2 tests fail only on ppc64

What are your OS, Python and Pillow versions?

• OS: RHEL 7.6
• Python: 3.6.6
• Pillow: 6.0.0

They fail for these two cases:

• mode=1, encoder_name=xbm, args=()
• mode=RGB, encoder_name=raw, args=RGB

--------------------------------------------------------------------
Pillow 6.0.0 TEST SUMMARY 
--------------------------------------------------------------------
Python modules loaded from /builddir/build/BUILD/Pillow-6.0.0/build/lib.linux-ppc64-3.6/PIL
Binary modules loaded from /builddir/build/BUILD/Pillow-6.0.0/build/lib.linux-ppc64-3.6/PIL
--------------------------------------------------------------------
--- PIL CORE support ok
--- TKINTER support ok
--- FREETYPE2 support ok
--- LITTLECMS2 support ok
--- WEBP support ok
--- WEBP Transparency support ok
*** WEBPMUX support not installed
*** WEBP Animation support not installed
--- JPEG support ok
--- OPENJPEG (JPEG2000) support ok
--- ZLIB (PNG/ZIP) support ok
--- LIBTIFF support ok
*** RAQM (Bidirectional Text) support not installed
--------------------------------------------------------------------
Running selftest:
**********************************************************************
File "selftest.py", line 101, in __main__.testimage
Failed example:
    len(im.convert("1").tobitmap())
Exception raised:
    Traceback (most recent call last):
      File "/usr/lib64/python3.6/doctest.py", line 1330, in __run
        compileflags, 1), test.globs)
      File "<doctest __main__.testimage[32]>", line 1, in <module>
        len(im.convert("1").tobitmap())
      File "/builddir/build/BUILD/Pillow-6.0.0/build/lib.linux-ppc64-3.6/PIL/Image.py", line 785, in tobitmap
        data = self.tobytes("xbm")
      File "/builddir/build/BUILD/Pillow-6.0.0/build/lib.linux-ppc64-3.6/PIL/Image.py", line 758, in tobytes
        l, s, d = e.encode(bufsize)
    MemoryError
**********************************************************************
File "selftest.py", line 103, in __main__.testimage
Failed example:
    len(im.tobytes())
Exception raised:
    Traceback (most recent call last):
      File "/usr/lib64/python3.6/doctest.py", line 1330, in __run
        compileflags, 1), test.globs)
      File "<doctest __main__.testimage[33]>", line 1, in <module>
        len(im.tobytes())
      File "/builddir/build/BUILD/Pillow-6.0.0/build/lib.linux-ppc64-3.6/PIL/Image.py", line 758, in tobytes
        l, s, d = e.encode(bufsize)
    MemoryError
**********************************************************************