OpenSystemsDevelopment / qpdf

The following script was used to adjust test data:

----------
#!/usr/bin/env python3
import json
import sys
import re

def json_dumps(data):
    return json.dumps(data, ensure_ascii=False,
                      indent=2, separators=(',', ': '))

for filename in sys.argv[1:]:
    with open(filename, 'r') as f:
        data = json.loads(f.read())
    if 'objects' not in data:
        continue
    trailer = None
    to_sort = []
    for k, v in data['objects'].items():
        if k == 'trailer':
            trailer = v
        else:
            m = re.match(r'^(\d+) \d+ R', k)
            if m:
                to_sort.append([int(m.group(1)), k, v])
    newobjects = {x[1]: x[2] for x in sorted(to_sort)}
    if trailer is not None:
        newobjects['trailer'] = trailer
    data['objects'] = newobjects
print(json_dumps(data))
----------

This commit just changes the order in which fields are written to the
json without changing their content. All the json files in the test
suite were modified with this script to ensure that we didn't get any
changes other than ordering.

----------
#!/usr/bin/env python3
import json
import sys

def json_dumps(data):
    return json.dumps(data, ensure_ascii=False,
                      indent=2, separators=(',', ': '))

for filename in sys.argv[1:]:
    with open(filename, 'r') as f:
        data = json.loads(f.read())
    newdata = {}
    for i in ('version', 'parameters', 'pages', 'pagelabels',
              'acroform', 'attachments', 'encrypt', 'outlines',
              'objects', 'objectinfo'):
        if i in data:
            newdata[i] = data[i]
print(json_dumps(newdata))
----------

Testing json against schema requires an in-memory copy, so do it only
when requested by the test suite.

We used to have to do that, but for quite some time, the code that
gets images has no longer required it.

Prevent my future self or other contributors from using assert in
tests and then having that assert not do anything because of the
NDEBUG macro.

Bidirectional base64; will be used by JSON v2.

This reverts commit dc059560e73e0b373a6e54e71b07e3af4b692cb4.

I changed my mind. There's no harm in leaving it deprecated for a
release cycle.

See ChangeLog for rationale for not deprecating it as originally
planned.

Where not possible, use "auto" to get the iterator type.

Editorial note: I have avoid this change for a long time because of
not wanting to make gratuitous changes to version history, which can
obscure when certain changes were made, but with having recently
touched every single file to apply automatic code formatting and with
making several broad changes to the API, I decided it was time to take
the plunge and get rid of the older (pre-C++11) verbose iterator
syntax. The new code is just easier to read and understand, and in
many cases, it will be more effecient as fewer temporary copies are
being made.

m-holger, if you're reading, you can see that I've finally come
around. :-)

Change .clang-format and commit automated changes from a fresh run of
format-code

It was being run at configuration time, not build time.

Make it so that a key with a null value is always treated as not being
present. This was inconsistent before.