Fix sign and conversion warnings (major)

This makes all integer type conversions that have potential data loss
explicit with calls that do range checks and raise an exception. After
this commit, qpdf builds with no warnings when -Wsign-conversion
-Wconversion is used with gcc or clang or when -W3 -Wd4800 is used
with MSVC. This significantly reduces the likelihood of potential
crashes from bogus integer values.

There are some parts of the code that take int when they should take
size_t or an offset. Such places would make qpdf not support files
with more than 2^31 of something that usually wouldn't be so large. In
the event that such a file shows up and is valid, at least qpdf would
raise an error in the right spot so the issue could be legitimately
addressed rather than failing in some weird way because of a silent
overflow condition.

1 files changed, 10 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index a9196159..713b954a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,9 +1,19 @@
 2019-06-20  Jay Berkenbilt  <ejb@ql.org>
 
+	* Fix all integer sign and conversion warnings. This makes all
+	integer type conversions that have potential data loss explicit
+	with calls that do range checks and raise an exception.
+
 	* Change out_bufsize argument to Pl_Flate's constructor for int to
 	unsigned int for compatibility with underlying zlib
 	implementation.
 
+	* Change QPDFObjectHandle::pipeStreamData's encode_flags argument
+	from unsigned long to int since int is the underlying type of the
+	enumerated type values that are passed to it. This change should
+	be invisible to virtually all code unless you are compiling with
+	strict warning flags and explicitly casting to unsigned long.
+
 	* Add methods to QPDFObjectHandle to return the value of Integer
 	objects as int and unsigned int with range checking and fallback
 	behavior to avoid silent underflow/overflow conditions.