This remained undetected for a long time as HeaderCheck is disabled by
default. This commit makes the following file compile again:
// file: compile_me.cpp
#include <LibDNS/Question.h>
// That's it, this was enough to cause a compilation error.
Likewise for most other files touched by this commit.
conditionally_parse_page_tree_node used to assume that the xref table
contained a byte offset, even for compressed objects. It now uses the
common facilities for parsing objects, at the expense of some
performance.
When looking up differences in the specified encoding, we previously
didn't recognize a lot of characters, namely those that are referred to
by a string in the PDF itself, like "/germandbls".
We now create a mapping of those characters to the code points they are
referring to, and correctly look them up when needed.
As per spec, the positioning (or kerning) parameter of this operator
should translate the text matrix before the next showing of text.
Previously, this calculation was slightly wrong and also only applied
after the text was already shown.
Now, whenever the xref table points to a compressed object,
parse_object_with_index will look it up in the corresponding object
stream as if it were a regular object.
With this, our parser gains the bare minimum support for xref streams.
Since PDF version 1.5, a document may omit the xref table in favor of
a new kind of xref stream object. This is used to reference so-called
"compressed" objects that are part of an object stream.
With this patch we are able to parse this new kind of xref object, but
we'll have to implement object streams to use them correctly.
The Parser class is now a generic PDF object parser, of which the new
DocumentParser class derives. DocumentParser now takes over all
functions relating to linearization, pages, xref and trailer handling.
This allows the use of multiple parsers in the same document's
context, which will be needed in order to handle PDF object streams.
This prevents us from needing a sv suffix, and potentially reduces the
need to run generic code for a single character (as contains,
starts_with, ends_with etc. for a char will be just a length and
equality check).
No functional changes.
Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).
No functional changes.
These are mostly minor mistakes I've encountered while working on the
removal of StringView(char const*). The usage of builder.put_string over
Format<FormatString>::format is preferrable as it will avoid the
indirection altogether when there's no formatting to be done. Similarly,
there is no need to do format(builder, "{}", number) when
builder.put_u64(number) works equally well.
Additionally a few Strings where only constant strings were used are
replaced with StringViews.
Security handlers manage encryption and decription of PDF files. The
standard security handler uses RC4/MD5 to perform its crypto (AES as
well, but that is not yet implemented).
This was a small optimization to allow a stream object to simply hold
a reference to the bytes in a PDF document rather than duplicating
them. However, as we move into features such as encryption, this
optimization does more harm than good. This can be revisited in the
future if necessary.
Incorrect is in quotes because the spec (both 1.7 and 2.0) specify this
multiplication as it was originally! However, flipping the order of
operations here makes the text in all of my test cases render in the
correct position.
The CTM is a transformation matrix between the text coordinate system
and the device coordinate system. However, being on the right-side of
the multiplication means that the CTM scale parameters don't have any
influence on the translation component of the left-side matrix. This
oddity is what originally led to me just trying this change to see if
it worked.
