Convert README files to markdown

Jay Berkenbilt
1 parent 6219111e
Showing 5 changed files with 224 additions and 600 deletions
README-hardening.md
README-maintainer.md
README-what-to-download.md
README-windows.md
README.md
-Avoiding operator[]
-===================
+# Avoiding `operator[]`
  
-During a security review by Red Hat security team (specifically
-Florian Weimer), it was discovered that qpdf used std::string and
-std::vector's operator[], which has no bounds checking by design.
-Instead, using those objects' at() method is preferable since it does
-bounds checking.  Florian has a tool that can detect all uses of these
-methods and report them.  I have a short perl script that
-automatically corrects any such uses.  The perl script is not intended
-to be general, but it could be reasonably general.  The only known
-shortcut is that it might not work very well with some cases of nested
-[]'s like a[b[c]] or with cases where there are line breaks inside the
-brackets.  For qpdf's coding style, it worked on all cases reported.
+During a security review by Red Hat security team (specifically Florian Weimer), it was discovered that qpdf used `std::string` and `std::vector`'s `operator[]`, which has no bounds checking by design. Instead, using those objects' `at()` method is preferable since it does bounds checking.  Florian has a tool that can detect all uses of these methods and report them.  I have a short perl script that automatically corrects any such uses.  The perl script is not intended to be general, but it could be reasonably general.  The only known shortcut is that it might not work very well with some cases of nested `[]`'s like `a[b[c]]` or with cases where there are line breaks inside the brackets.  For qpdf's coding style, it worked on all cases reported.
  
-To use this, obtain htcondor-analyzer, run it, and respond to the
-report.  Here's what I did.
+To use this, obtain htcondor-analyzer, run it, and respond to the report.  Here's what I did.
  
+```
 sudo aptitude install libclang-dev llvm llvm-dev clang
 cd /tmp
 git clone https://github.com/fweimer/htcondor-analyzer
 # HEAD = 5fa06fc68a9b0677e9de162279185d58ba1e8477 at this writing
 cd htcondor-analyzer
 make
+```
  
-in qpdf
+In qpdf:
  
+```
 ./autogen.sh
 /tmp/htcondor-analyzer/create-db
 CC=/tmp/htcondor-analyzer/cc CXX=/tmp/htcondor-analyzer/cxx ./configure --disable-shared --disable-werror
 # to remove conftest.c
 \rm htcondor-analyzer.sqlite
 /tmp/htcondor-analyzer/create-db
+```
  
 Repeat until no more errors:
  
+```
 /tmp/fix-at.pl is shown below.
+```
  
+```
 make
 /tmp/htcondor-analyzer/report | grep std:: | grep qpdf >| /tmp/r
 perl /tmp/fix-at.pl /tmp/r
 # move all *.new over the original file.  patmv is my script.  Can
 # also use a for loop.
 patmv -f s/.new// **/*.new
+```
  
----------- /tmp/fix-at.pl ----------
+/tmp/fix-at.pl:
+```perl
 #!/usr/bin/env perl
 require 5.008;
 use warnings;
@@ -90,4 +87,4 @@ foreach my $file (sort keys %to_fix)
     }
     close(F) or die;
 }
---------------------
+```
-Release Reminders
-=================
-
- * Test for binary compatility. The easiest way to do this is to check
-   out the last release, run the test suite, check out the new
-   release, run make build_libqpdf, check out the old release, and run
-   make check NO_REBUILD=1.
-
- * When making a release, always remember to run large file tests and
-   image comparison tests (--enable-test-compare-images
-   --with-large-file-test-path=/path). For Windows, use a Windows
-   style path, not an MSYS path for large files. For a major release,
-   consider running a spelling checker over the source code to catch
-   errors in variable names, strings, and comments. Use ispell -p
-   ispell-words.
-
- * Run tests with sanitize address enabled:
-
-   ./configure CFLAGS="-fsanitize=address -g" \
-      CXXFLAGS="-fsanitize=address -g" \
-      LDFLAGS="-fsanitize=address" \
-      --enable-werror --disable-shared
-
-   As of gcc 6.3.0, this exposes some good things but appears to also
-   have some false positive leak reports. Valgrind is more reliable
-   but also may miss some things that this catches.
-
- * Consider running tests with latest gcc and/or valgrind. To test
-   with valgrind:
-
-   ./configure --disable-shared
-   make -j8 -k VALGRIND=1
-   make -k check NO_REBUILD=1
-
-   This moves each binary into a subdirectory and replaces it with a
-   link to make/exec-z. See make/exec-z.
-
- * Check all open issues in the sourceforge trackers and on github.
-
- * If any interfaces were added or changed, check C API to see whether
-   changes are appropriate there as well.  If necessary, review the
-   casting policy in the manual, and ensure that integer types are
-   properly handled.
-
- * Remember to avoid using operator[] with std::string or
-   std::vector.  See README-hardening.md for details.
-
- * Increment shared library version information as needed (LT_* in
-   configure.ac)
-
- * Update release notes in manual -- look at diffs and ChangeLog
-
- * Add a release entry to ChangeLog
-
- * Make sure version numbers are consistent in the following
-   locations:
-
-     configure.ac
-     libqpdf/QPDF.cc
-     manual/qpdf-manual.xml
-
-   make_dist verifies this consistency.
-
- * Update release date in manual/qpdf-manual.xml.  Remember to ensure
-   that the entities at the top of the document are consistent with
-   the release notes for both version and release date.
-
- * Check TODO file to make sure all planned items for the release are
-   done or retargeted.
-
- * Each year, update copyright notices. Just do a case-insensitive
-   search for copyright. Don't forget copyright in manual. Also update
-   debian copyright in debian package. Last updated: 2017.
-
- * To construct a source distribution from a pristine checkout,
-   make_dist does the following:
-
-    ./autogen.sh
-    ./configure --enable-doc-maintenance --enable-werror
-    make build_manual
-    make distclean
-
- * To create a source release, do an export from the version control
-   system to a directory called qpdf-version.  For example, from this
-   directory:
-
-   rm -rf /tmp/qpdf-x.y.z
-   git archive --prefix=qpdf-x.y.z/ HEAD . | (cd /tmp; tar xf -)
-
-   From the parent of that directory, run make_dist with the directory
-   as an argument.  Remember to have fop in your path.  For internally
-   testing releases, you can run make_dist with the --no-tests option.
-
- * To create a source release of external libs, do an export from the
-   version control system into a directory called qpdf-external-libs
-   and just make a zip file of the result called
-   qpdf-external-libs-src.zip.  See the README.txt file there for
-   information on creating binary external libs releases. Run this
-   from the external-libs repository:
-
-   git archive --prefix=external-libs/ HEAD . | (cd /tmp; tar xf -)
-   cd /tmp
-   zip -r qpdf-external-libs-src.zip external-libs
-
- * To create Windows binary releases, extract the qpdf source
-   distribution in Windows (MSYS + MINGW, MSVC).  From the extracted
-   directory, extract the binary distribution of the external
-   libraries.  Run ./make_windows_releases from there.  You will need
-   to have zip in your path.
-
- * Before releasing, rebuild and test debian package.
-
- * Remember to copy README-what-to-download.md separately onto the
-   download area.
-
- * Remember to update the web page including putting new documentation
-   in the "files" subdirectory of the website on sourceforge.net.
-
- * Create a tag in the version control system, and make backups of the
-   actual releases.  With git, use git tag -s to create a signed tag:
-
-   git tag -s release-qpdf-$version HEAD -m"qpdf $version"
-
- * When releasing on sourceforge, external-libs distributions go in
-   external-libs/yyyymmdd, and qpdf distributions go in qpdf/vvv.
-   Make the source package the default for all but Windows, and make
-   the 32-bit mingw build the default for Windows.
-
-
-General Build Stuff
-===================
-
-QPDF uses autoconf and libtool but does not use automake.  The only
-files distributed with the qpdf source distribution that are not
-controlled are "configure", "libqpdf/qpdf/qpdf-config.h.in",
-"aclocal.m4", and some documentation.  See above for the steps
-required to prepare a source distribution.
-
-A small handful of additional files have been taken from autotools
-programs.  These should probably be updated from time to time.
-
- * config.guess, config.sub, ltmain.sh, and the m4 directory: these
-   were created by running libtoolize -c.  To update, run libtoolize
-   -f -c or remove the files and rerun libtoolize.
-
- * Other files copied as indicated:
-
-   cp /usr/share/automake-1.11/install-sh .
-   cp /usr/share/automake-1.11/mkinstalldirs .
-
-The entire contents of the m4 directory came from libtool.m4.  If we
-had some additional local parts, we could also add those to the m4
-directory.  In order for this to work, it is necessary to run "aclocal
--I m4" before running autoheader and autoconf.
-
-If building or editing documentation, configure with
---enable-doc-maintenance.  This will ensure that all tools or files
-required to validate and build documentation are available.
-
-If you want to run make maintainer-clean or make distclean and you
-haven't run ./configure, you can pass CLEAN=1 to make on the command
-line to prevent it from complaining about configure not having been
-run.
-
-Local Windows Testing Procedure
-===============================
+# Release Reminders
+
+* Test for binary compatility. The easiest way to do this is to check out the last release, run the test suite, check out the new release, run `make build_libqpdf`, check out the old release, and run `make check NO_REBUILD=1`.
+* When making a release, always remember to run large file tests and image comparison tests (`--enable-test-compare-images` `--with-large-file-test-path=/path`). For Windows, use a Windows style path, not an MSYS path for large files. For a major release, consider running a spelling checker over the source code to catch errors in variable names, strings, and comments. Use `ispell -p ispell-words`.
+* Run tests with sanitize address enabled:
+  ```
+  ./configure CFLAGS="-fsanitize=address -g" \
+     CXXFLAGS="-fsanitize=address -g" \
+     LDFLAGS="-fsanitize=address" \
+     --enable-werror --disable-shared
+  ```
+  As of gcc 6.3.0, this exposes some good things but appears to also have some false positive leak reports. Valgrind is more reliable but also may miss some things that this catches.
+* Consider running tests with latest gcc and/or valgrind. To test with valgrind:
+  ```
+  ./configure --disable-shared
+  make -j8 -k VALGRIND=1
+  make -k check NO_REBUILD=1
+  ```
+  This moves each binary into a subdirectory and replaces it with a link to make/exec-z. See make/exec-z.
+* Check all open issues in the sourceforge trackers and on github.
+* If any interfaces were added or changed, check C API to see whether changes are appropriate there as well.  If necessary, review the casting policy in the manual, and ensure that integer types are properly handled.
+* Remember to avoid using `operator[]` with `std::string` or `std::vector`. Instead, use `at()`. See README-hardening.md for details.
+* Increment shared library version information as needed (`LT_*` in `configure.ac`)
+* Update release notes in manual. Look at diffs and ChangeLog.
+* Add a release entry to ChangeLog.
+* Make sure version numbers are consistent in the following locations:
+  * configure.ac
+  * libqpdf/QPDF.cc
+  * manual/qpdf-manual.xml
+  `make_dist` verifies this consistency.
+* Update release date in `manual/qpdf-manual.xml`.  Remember to ensure that the entities at the top of the document are consistent with the release notes for both version and release date.
+* Check `TODO` file to make sure all planned items for the release are done or retargeted.
+* Each year, update copyright notices. Just do a case-insensitive search for copyright. Don't forget copyright in manual. Also update debian copyright in debian package. Last updated: 2017.
+* To construct a source distribution from a pristine checkout, `make_dist` does the following:
+  ```
+  ./autogen.sh
+  ./configure --enable-doc-maintenance --enable-werror
+  make build_manual
+  make distclean
+  ```
+* To create a source release, do an export from the version control system to a directory called qpdf-version.  For example, from this directory:
+  ```
+  rm -rf /tmp/qpdf-x.y.z
+  git archive --prefix=qpdf-x.y.z/ HEAD . | (cd /tmp; tar xf -)
+  ```
+  From the parent of that directory, run `make_dist` with the directory as an argument.  Remember to have fop in your path.  For internally testing releases, you can run make_dist with the `--no-tests` option.
+* To create a source release of external libs, do an export from the version control system into a directory called `qpdf-external-libs` and just make a zip file of the result called `qpdf-external-libs-src.zip`.  See the README.txt file there for information on creating binary external libs releases. Run this from the external-libs repository:
+  ```
+  git archive --prefix=external-libs/ HEAD . | (cd /tmp; tar xf -)
+  cd /tmp
+  zip -r qpdf-external-libs-src.zip external-libs
+  ```
+* To create Windows binary releases, extract the qpdf source distribution in Windows (MSYS2 + MSVC).  From the extracted directory, extract the binary distribution of the external libraries.  Run ./make_windows_releases from there.
+* Before releasing, rebuild and test debian package.
+* Remember to copy `README-what-to-download.md` separately onto the download area.
+* Remember to update the web page including putting new documentation in the `files` subdirectory of the website on sourceforge.net.
+* Create a tag in the version control system, and make backups of the actual releases.  With git, use git `tag -s` to create a signed tag:
+  ```
+  git tag -s release-qpdf-$version HEAD -m"qpdf $version"
+  ```
+* When releasing on sourceforge, `external-libs` distributions go in `external-libs/yyyymmdd`, and qpdf distributions go in `qpdf/vvv`. Make the source package the default for all but Windows, and make the 32-bit mingw build the default for Windows.
+
+# General Build Stuff
+
+QPDF uses autoconf and libtool but does not use automake.  The only files distributed with the qpdf source distribution that are not controlled are `configure`, `libqpdf/qpdf/qpdf-config.h.in`, `aclocal.m4`, and some documentation.  See above for the steps required to prepare a source distribution.
+
+A small handful of additional files have been taken from autotools programs.  These should probably be updated from time to time.
+* `config.guess`, `config.sub`, `ltmain.sh`, and the `m4` directory: these were created by running `libtoolize -c`.  To update, run `libtoolize -f -c` or remove the files and rerun `libtoolize`.
+* Other files copied as indicated:
+  ```
+  cp /usr/share/automake-1.11/install-sh .
+  cp /usr/share/automake-1.11/mkinstalldirs .
+  ```
+
+The entire contents of the `m4` directory came from `libtool.m4`.  If we had some additional local parts, we could also add those to the `m4` directory.  In order for this to work, it is necessary to run `aclocal -I m4` before running `autoheader` and `autoconf`. The `autogen.sh` script handles this.
+
+If building or editing documentation, configure with `--enable-doc-maintenance`.  This will ensure that all tools or files required to validate and build documentation are available.
+
+If you want to run `make maintainer-clean`, `make distclean`, or `make autofiles.zip` and you haven't run `./configure`, you can pass `CLEAN=1` to make on the command line to prevent it from complaining about configure not having been run.
+
+If you want to run checks without rerunning the build, pass `NO_REBUILD=1` to make. This can be useful for special testing scenarios such as valgrind or binary compatibility.
+
+# Local Windows Testing Procedure
  
 This is what I do for routine testing on Windows.
  
-From Linux, run ./autogen.sh and make autofiles.zip
+From Linux, run `./autogen.sh` and `make autofiles.zip CLEAN=1`.
  
-From Windows, git clone from my Linux clone, unzip external-libs, and
-unzip autofiles.zip.
+From Windows, git clone from my Linux clone, unzip `external-libs`, and unzip `autofiles.zip`.
  
-Look at make_windows_releases. Set up path the same way and run
-whichever ./config-* is appropriate for whichever compiler I need to
-test with. Run from msys started from one of the visual studio command
-line shells. The build doesn't work from git bash on my local system.
+Look at `make_windows_releases`. Set up path the same way and run whichever `./config-*` is appropriate for whichever compiler I need to test with. Start one of the Visual Studio native compiler shells, and from there, run one of the msys shells. The Visual Studio step is not necessary if just building with mingw.
-To build from source for Linux or other UNIX/UNIX-like systems, it is
-generally sufficient to download just the source qpdf-<version>.tar.gz
-file.
+To build from source for Linux or other UNIX/UNIX-like systems, it is generally sufficient to download just the source `qpdf-<version>.tar.gz` file.
  
-For Windows, there are several additional files that you might want to
-download.
+For Windows, there are several additional files that you might want to download.
  
- * qpdf-<version>-bin-mingw32.zip
+* `qpdf-<version>-bin-mingw32.zip`
  
-   If you just want to use the qpdf command line program or use the
-   qpdf DLL's C-language interface, you can download this file.  You
-   can also download this version if you are using MINGW's gcc 4.6 (or
-   a binary compatible version) and want to program using the C++
-   interface.
+   If you just want to use the qpdf command line program or use the qpdf DLL's C-language interface, you can download this file.  You can also download this version if you are using MINGW's gcc and want to program using the C++ interface.
  
- * qpdf-<version>-bin-mingw64.zip
+* `qpdf-<version>-bin-mingw64.zip`
  
-   A 64-bit version built with mingw.  Use this for 64-bit Windows
-   systems.  The 32-bit version will also work on Windows 64-bit.
-   Both the 32-bit and the 64-bit version support files over 2 GB in
-   size, but you may find it easier to integrate this with your own
-   software if you use the 64-bit version.
+   A 64-bit version built with mingw.  Use this for 64-bit Windows systems.  The 32-bit version will also work on Windows 64-bit. Both the 32-bit and the 64-bit version support files over 2 GB in size, but you may find it easier to integrate this with your own software if you use the 64-bit version.
  
- * qpdf-<version>-bin-msvc32.zip
+* `qpdf-<version>-bin-msvc32.zip`
  
-   If you want to program using qpdf's C++ interface and you are using
-   Microsoft Visual C++ 2010 in 32-bit mode, you can download this
-   file.
+  If you want to program using qpdf's C++ interface and you are using Microsoft Visual C++ 2015 in 32-bit mode, you can download this file.
  
- * qpdf-<version>-bin-msvc64.zip
+* `qpdf-<version>-bin-msvc64.zip`
  
-   If you want to program using qpdf's C++ interface and you are using
-   Microsoft Visual C++ 2010 in 64-bit mode, you can download this
-   file.
+  If you want to program using qpdf's C++ interface and you are using Microsoft Visual C++ 2015 in 64-bit mode, you can download this file.
  
- * qpdf-external-libs-bin.zip
+* `qpdf-external-libs-bin.zip`
  
-   If you want to build qpdf for Windows yourself with either MINGW or
-   MSVC 2010, you can download this file and extract it inside the
-   qpdf source distribution.  Please refer to README-windows.md in
-   the qpdf source distribution for additional details.  Note that you
-   need the 2012-06-20 version or later to be able to build qpdf 3.0
-   or newer.  The 2009-10-24 version is required for qpdf 2.3.1 or
-   older.
+  If you want to build qpdf for Windows yourself with either MINGW or MSVC 2015, you can download this file and extract it inside the qpdf source distribution.  Please refer to README-windows.md in the qpdf source distribution for additional details.  Note that you need the 2017-08-21 version or later to be able to build qpdf 7.0 or newer. Generally grab the `external-libs` distribution that was the latest version at the time of the release of whichever version of qpdf you are building.
  
- * qpdf-external-libs-src.zip
+* `qpdf-external-libs-src.zip`
  
-   If you want to build the external libraries on your own (for
-   Windows or anything else), you can download this archive. In
-   addition to including an unmodified distribution zlib and the jpeg
-   libary, it includes a README file and some scripts to help you
-   build it for Windows. qpdf was built using a binary distribution of
-   libjpeg-turbo for Windows. You will also have to provide those. See
-   README-windows.md for details.
+  If you want to build the external libraries on your own (for Windows or anything else), you can download this archive. In addition to including an unmodified distribution `zlib` and the `jpeg` libary, it includes a `README` file and some scripts to help you build it for Windows. You will also have to provide those.
+
+If you want to build on Windows, please see also README-windows.md in the qpdf source distribution.
  
-If you want to build on Windows, please see also README-windows.md.
 Common Setup
 ============
  
-You may need to disable antivirus software to run qpdf's test suite.
+You may need to disable antivirus software to run qpdf's test suite. Running Windows Defender on Windows 10 does not interfere with building or running qpdf or its test suite.
  
-To be able to build qpdf and run its test suite, you must have MSYS2
-installed. This replaces the old process of having a mixture of msys,
-mingw-w64, and ActiveState perl. It is now possible to do everything
-with just MSYS2.
+To be able to build qpdf and run its test suite, you must have MSYS2 installed. This replaces the old process of having a mixture of msys, mingw-w64, and ActiveState perl. It is now possible to do everything with just MSYS2.
  
 Here's what I did on my system:
  
@@ -16,214 +13,95 @@ Here&#39;s what I did on my system:
 * From the prompt:
   * Run `pacman -Syuu` and follow the instructions, which may tell you
     to close the window and rerun the command multiple times.
-  * pacman -S make base-devel git zip unzip
-  * pacman -S mingw-w64-x86_64-toolchain mingw-w64-i686-toolchain
-
-If you would like to build with Microsoft Visual C++, install a
-suitable Microsoft Visual Studio edition. In early 2016, 2015
-community edition with C++ support is fine. It may crash a few times
-during installation, but repeating the installation will allow it to
-finish, and the resulting software is stable.
-
-To build qpdf with Visual Studio, start the msys2 mingw32 or mingw64
-shell from a command window started from one of the Visual Studio
-shell windows. You must use the mingw shell for the same word size (32
-or 64 bit) as the Windows compiler since the MSVC build uses objdump
-from the msys distribution. You must also have it inherit the path.
-For example:
+  * `pacman -S make base-devel git zip unzip`
+  * `pacman -S mingw-w64-x86_64-toolchain mingw-w64-i686-toolchain`
  
-* Start x64 native tools command prompt from msvc
-* set MSYS2_PATH_TYPE=inherit
-* C:\msys64\mingw64
-
-Image comparison tests are disabled by default, but it is possible to
-run them on Windows. To do so, add --enable-test-compare-images from
-the configure statements given below and install some additional
-third-party dependencies. These may be provided in an environment such
-as MSYS or Cygwin or can be downloaded separately for other
-environments. You may extract or install the following software into
-separate folders each and add the "bin" folder to your "PATH"
-environment variable to make executables and DLLs available. If
-installers are provided, they might do that already by default.
-
- * LibJpeg (http://gnuwin32.sourceforge.net/packages/jpeg.htm)
-
-   This archive provides some needed DLLs needed by LibTiff.
-
- * LibTiff (http://gnuwin32.sourceforge.net/packages/tiff.htm)
-
-   This archive provides some needed binaries and DLLs if you want to
-   use the image comparison tests. It depends on some DLLs from
-   LibJpeg.
-
- * GhostScript (http://www.ghostscript.com/download/gsdnld.html)
+If you would like to build with Microsoft Visual C++, install a suitable Microsoft Visual Studio edition. In early 2016, 2015 community edition with C++ support is fine. It may crash a few times during installation, but repeating the installation will allow it to finish, and the resulting software is stable.
  
-   GhostScript is needed for image comparison tests. It's important
-   that the binary is available as "gs", while its default name is
-   "gswin32[c].exe". You can either copy one of the original files,
-   use "mklink" to create a hard-/softlink, or provide a custom
-   "gs.cmd" wrapper that forwards all arguments to one of the original
-   binaries. Using "mklink" with "gswin32c.exe" is probably the best
-   choice.
+To build qpdf with Visual Studio, start the msys2 mingw32 or mingw64 shell from a command window started from one of the Visual Studio shell windows. You must use the mingw shell for the same word size (32 or 64 bit) as the Windows compiler since the MSVC build uses objdump from the msys distribution. You must also have it inherit the path. For example:
  
+* Start x64 native tools command prompt from msvc
+* `set MSYS2_PATH_TYPE=inherit`
+* `C:\msys64\mingw64`
  
-External Libraries
-==================
-
-In order to build qpdf, you must have a copy of zlib and the jpeg
-library. The easy way to get it is to download the external libs from
-the qpdf download area. There are packages called
-external-libs-bin.zip and external-libs-src.zip. If you are building
-with MSVC 2015 or MINGW with MSYS2, you can just extract the
-qpdf-external-libs-bin.zip zip file into the top-level qpdf source
-tree. Note that you need the 2017-08-21 version (at least) to build
-qpdf 7.0 or greater since this includes jpeg. Passing
---enable-external-libs to ./configure (which is done automatically if
-you follow the instructions below) is sufficient to find them.
-
-You can also obtain zlib and jpeg directly on your own and install
-them. If you are using mingw, you can just set CPPFLAGS, LDFLAGS, and
-LIBS when you run ./configure so that it can find the header files and
-libraries. If you are building with msvc and you want to do this, it
-probably won't work because ./configure doesn't know how to interpret
-LDFLAGS and LIBS properly for MSVC (though qpdf's own build system
-does). In this case, you can probably get away with cheating by
-passing --enable-external-libs to ./configure and then just editing
-CPPFLAGS, LDFLAGS, LIBS in the generated autoconf.mk file. Note that
-you should use UNIX-like syntax (-I, -L, -l) even though this is not
-what cl takes on the command line. qpdf's build rules will fix it.
+Image comparison tests are disabled by default, but it is possible to run them on Windows. To do so, add `--enable-test-compare-images` from the configure statements given below and install some additional third-party dependencies. These may be provided in an environment such as MSYS or Cygwin or can be downloaded separately for other environments. You may extract or install the following software into separate folders each and add the `bin` folder to your `PATH` environment variable to make executables and DLLs available. If installers are provided, they might do that already by default.
  
-You can also download qpdf-external-libs-src.zip and follow the
-instructions in the README.txt there for how to build external libs.
+* [LibJpeg](http://gnuwin32.sourceforge.net/packages/jpeg.htm): This archive provides some needed DLLs needed by LibTiff.
+* [LibTiff](http://gnuwin32.sourceforge.net/packages/tiff.htm): This archive provides some needed binaries and DLLs if you want to use the image comparison tests. It depends on some DLLs from LibJpeg.
+* [GhostScript](http://www.ghostscript.com/download/gsdnld.html): GhostScript is needed for image comparison tests. It's important that the binary is available as `gs`, while its default name is `gswin32[c].exe`. You can either copy one of the original files, use `mklink` to create a hard/softlink, or provide a custom `gs.cmd` wrapper that forwards all arguments to one of the original binaries. Using `mklink` with `gswin32c.exe` is probably the best choice.
  
+# External Libraries
  
-Building from version control
-=============================
+In order to build qpdf, you must have a copy of `zlib` and the `jpeg` library. The easy way to get it is to download the external libs from the qpdf download area. There are packages called `external-libs-bin.zip` and `external-libs-src.zip`. If you are building with MSVC 2015 or MINGW with MSYS2, you can just extract the `qpdf-external-libs-bin.zip` zip file into the top-level qpdf source tree. Note that you need the 2017-08-21 version (at least) to build qpdf 7.0 or greater since this includes jpeg. Passing `--enable-external-libs` to `./configure` (which is done automatically if you follow the instructions below) is sufficient to find them.
  
-If you check out qpdf from version control, you will not have the
-files that are generated by autoconf.  If you are not changing these
-files, you can grab them from a source distribution or create them
-from a system that has autoconf.  To create them from scratch, run
-./autogen.sh on a system that has autoconf installed.  Once you have
-them, you can run make CLEAN=1 autofiles.zip.  This will create an
-autofiles.zip that you can extract on top of a fresh checkout.
+You can also obtain `zlib` and `jpeg` directly on your own and install them. If you are using mingw, you can just set `CPPFLAGS`, `LDFLAGS`, and `LIBS` when you run ./configure so that it can find the header files and libraries. If you are building with MSVC and you want to do this, it probably won't work because `./configure` doesn't know how to interpret `LDFLAGS` and `LIBS` properly for MSVC (though qpdf's own build system does). In this case, you can probably get away with cheating by passing `--enable-external-libs` to `./configure` and then just editing `CPPFLAGS`, `LDFLAGS`, `LIBS` in the generated autoconf.mk file. Note that you should use UNIX-like syntax (`-I`, `-L`, `-l`) even though this is not what cl takes on the command line. qpdf's build rules will fix it.
  
+You can also download `qpdf-external-libs-src.zip` and follow the instructions in the README.txt there for how to build external libs.
  
-Building with MinGW
-===================
+# Building from version control
  
-QPDF is known to build and pass its test suite with MSYS2 using the
-32-bit and 64-bit compilers from that project and Microsoft Visual C++
-2015, both 32-bit and 64-bit versions. MSYS2 is required to build as
-well in order to get make and other related tools. See common setup at
-the top of this file for installation and configuration of MSYS2.
-Then, from the suitable 32-bit or 64-bit environment, run
+If you check out qpdf from version control, you will not have the files that are generated by autoconf.  If you are not changing these files, you can grab them from a source distribution or create them from a system that has autoconf.  To create them from scratch, run `./autogen.sh` on a system that has autoconf installed.  Once you have them, you can run `make CLEAN=1 autofiles.zip`.  This will create an autofiles.zip that you can extract on top of a fresh checkout.
  
-  ./config-mingw
+# Building with MinGW
  
-and then
+QPDF is known to build and pass its test suite with MSYS2 using the 32-bit and 64-bit compilers. MSYS2 is required to build as well in order to get make and other related tools. See common setup at the top of this file for installation and configuration of MSYS2. Then, from the suitable 32-bit or 64-bit environment, run
  
-  make
+```
+./config-mingw
+make
+```
  
-Note that ./config-mingw just runs ./configure with specific
-arguments, so you can look at it, make adjustments, and manually run
-configure instead.
+Note that `./config-mingw` just runs `./configure` with specific arguments, so you can look at it, make adjustments, and manually run configure instead.
  
-Add the absolute path to the libqpdf/build directory to your PATH.
-Make sure you can run the qpdf command by typing qpdf/build/qpdf and
-making sure you get a help message rather than an error loading the
-DLL or no output at all.  Run the test suite by typing
+Add the absolute path to the `libqpdf/build` directory to your `PATH`. Make sure you can run the qpdf command by typing qpdf/build/qpdf and making sure you get a help message rather than an error loading the DLL or no output at all.  Run the test suite by typing
  
-  make check
+```
+make check
+```
  
 If all goes well, you should get a passing test suite.
  
-To create an installation directory, run make install.  This will
-create install-mingw/qpdf-VERSION and populate it.  The binary
-download of qpdf for Windows with mingw is created from this
-directory.
-
-You can also take a look at make_windows_releases for reference.  This
-is how the distributed Windows executables are created.
+To create an installation directory, run `make install`.  This will create `install-mingw/qpdf-VERSION` and populate it.  The binary download of qpdf for Windows with mingw is created from this directory.
  
+You can also take a look at `make_windows_releases` for reference.  This is how the distributed Windows executables are created.
  
-Building with MSVC 2015
-=======================
+# Building with MSVC 2015
  
-These instructions would likely work with newer versions of MSVC and
-are known to have worked with versions as old as 2008 Express.
+These instructions would likely work with newer versions of MSVC and are known to have worked with versions as old as 2008 Express.
  
-You should first set up your environment to be able to run MSVC from
-the command line.  There is usually a batch file included with MSVC
-that does this.  Make sure that you start a command line environment
-configured for whichever of 32-bit or 64-bit output that you intend to
-build for.
+You should first set up your environment to be able to run MSVC from the command line.  There is usually a batch file included with MSVC that does this.  Make sure that you start a command line environment configured for whichever of 32-bit or 64-bit output that you intend to build for.
  
-From that cmd prompt, you can start your MSYS2 shell with path
-inheritance as described above.
+From that cmd prompt, you can start your MSYS2 shell with path inheritance as described above.
  
-Configure as follows:
+Configure and build as follows:
  
-  ./config-msvc
+```
+./config-msvc
+make
+```
  
-Once configured, run
+Note that `./config-msvc` just runs `./configure` with specific arguments, so you can look at it, make adjustments, and manually run configure instead.
  
-  make
+NOTE: automated dependencies are not generated with the msvc build. If you're planning on making modifications, you should probably work with mingw.  If there is a need, I can add dependency information to the msvc build, but since I only use it for generating release versions, I haven't bothered.
  
-Note that ./config-msvc just runs ./configure with specific arguments,
-so you can look at it, make adjustments, and manually run configure
-instead.
+Once built, add the full path to the `libqpdf/build` directory to your path and run
  
-NOTE: automated dependencies are not generated with the msvc build.
-If you're planning on making modifications, you should probably work
-with mingw.  If there is a need, I can add dependency information to
-the msvc build, but since I only use it for generating release
-versions, I haven't bothered.
+```
+make check
+```
  
-Once built, add the full path to the libqpdf/build directory to your
-path and run
+to run the test suite.
  
-  make check
+If you are building with MSVC and want to debug a crash in MSVC's debugger, first start an instance of Visual C++.  Then run qpdf.  When the abort/retry/ignore dialog pops up, first attach the process from within visual C++, and then click Retry in qpdf.
  
-to run the test suite.
+A release version of qpdf is built by default.  If you want to link against debugging libraries, you will have to change `/MD` to `/MDd` in `make/msvc.mk`.  Note that you must redistribute the Microsoft runtime DLLs.  Linking with static runtime (`/MT`) won't work; see "Static Runtime" below for details.
  
-If you are building with MSVC and want to debug a crash in MSVC's
-debugger, first start an instance of Visual C++.  Then run qpdf.  When
-the abort/retry/ignore dialog pops up, first attach the process from
-within visual C++, and then click Retry in qpdf.
+# Runtime DLLs
  
-A release version of qpdf is built by default.  If you want to link
-against debugging libraries, you will have to change /MD to /MDd in
-make/msvc.mk.  Note that you must redistribute the Microsoft runtime
-DLLs.  Linking with static runtime (/MT) won't work; see "Static
-Runtime" below for details.
+Both build methods create executables and DLLs that are dependent on the compiler's runtime DLLs.  When you run make install, the installation process will automatically detect the DLLs and copy them into the installation bin directory.  Look at the `copy_dlls` script for details on how this is accomplished.
  
+Redistribution of the runtime DLL is unavoidable as of this writing; see "Static Runtime" below for details.
  
-Runtime DLLs
-============
+# Static Runtime
  
-Both build methods create executables and DLLs that are dependent on
-the compiler's runtime DLLs.  When you run make install, the
-installation process will automatically detect the DLLs and copy them
-into the installation bin directory.  Look at the copy_dlls script for
-details on how this is accomplished.
-
-Redistribution of the runtime DLL is unavoidable as of this writing;
-see "Static Runtime" below for details.
-
-
-Static Runtime
-==============
-
-Building the DLL and executables with static runtime does not work
-with either Visual C++ .NET 2008 (a.k.a. vc9) using /MT or with mingw
-(at least as of 4.4.0) using -static-libgcc.  The reason is that, in
-both cases, there is static data involved with exception handling, and
-when the runtime is linked in statically, exceptions cannot be thrown
-across the DLL to EXE boundary.  Since qpdf uses exception handling
-extensively for error handling, we have no choice but to redistribute
-the C++ runtime DLLs.  Maybe this will be addressed in a future
-version of the compilers.  This has not been retested with the
-toolchain versions used to create qpdf 3.0 distributions. (This has
-not been revisited since MSVC 2008, but redistrbuting runtime DLLs is
-extremely common and should not be a problem.)
+Building the DLL and executables with static runtime does not work with either Visual C++ .NET 2008 (a.k.a. vc9) using `/MT` or with mingw (at least as of 4.4.0) using `-static-libgcc`.  The reason is that, in both cases, there is static data involved with exception handling, and when the runtime is linked in statically, exceptions cannot be thrown across the DLL to EXE boundary.  Since qpdf uses exception handling extensively for error handling, we have no choice but to redistribute the C++ runtime DLLs.  Maybe this will be addressed in a future version of the compilers.  This has not been retested with the toolchain versions used to create qpdf >= 3.0 distributions. This has not been revisited since MSVC 2008, but redistrbuting runtime DLLs is extremely common and should not be a problem.
-This is the QPDF package.  Information about it can be found at
-http://qpdf.sourceforge.net.  The source code repository is hosted
-at github: https://github.com/qpdf/qpdf.
+This is the QPDF package.  Information about it can be found at https://qpdf.sourceforge.net.  The source code repository is hosted at github: https://github.com/qpdf/qpdf.
  
 QPDF is copyright (c) 2005-2017 Jay Berkenbilt
  
-This software may be distributed under the terms of version 2 of the
-Artistic License which may be found in the source distribution as
-"Artistic-2.0".  It is provided "as is" without express or implied
-warranty.
+This software may be distributed under the terms of version 2 of the Artistic License which may be found in the source distribution as "Artistic-2.0".  It is provided "as is" without express or implied warranty.
  
+# Prerequisites
  
-Prerequisites
-=============
+QPDF depends on the external libraries [zlib](http://www.zlib.net/) and [jpeg](http://www.ijg.org/files/). The [libjpeg-turbo](https://libjpeg-turbo.org/) library is also known to work since it is compatible with the regular jpeg library, and QPDF doesn't use any interfaces that aren't present in the straight jpeg8 API. These are part of every Linux distribution and are readily available. Download information appears in the documentation. For Windows, you can download pre-built binary versions of these libraries for some compilers; see [README-windows.md](README-windows.md) for additional details.
  
-QPDF depends on the external libraries "zlib" and "jpeg". These are
-part of every Linux distribution and are readily available. Download
-information appears in the documentation. For Windows, you can
-download pre-built binary versions of these libraries for some
-compilers; see README-windows.md for additional details.
+QPDF requires a C++ compiler that works with STL.  Your compiler must also support `long long`.  Almost all modern compilers do.  If you are trying to port qpdf to a compiler that doesn't support `long long`, you could change all occurrences of `long long` to `long` in the source code, noting that this would break binary compatibility with other builds of qpdf.  Doing so would certainly prevent qpdf from working with files larger than 2 GB, but remaining functionality would most likely work fine.  If you built qpdf this way and it passed its test suite with large file support disabled, you could be confident that you had an otherwise working qpdf.
  
-QPDF requires a C++ compiler that works with STL.  Your compiler must
-also support "long long".  Almost all modern compilers do.  If you are
-trying to port qpdf to a compiler that doesn't support long long, you
-could change all occurrences of "long long" to "long" in the source
-code, noting that this would break binary compatibility with other
-builds of qpdf.  Doing so would certainly prevent qpdf from working
-with files larger than 2 GB, but remaining functionality would most
-likely work fine.  If you built qpdf this way and it passed its test
-suite with large file support disabled, you could be confident that
-you had an otherwise working qpdf.
+# Licensing terms of embedded software
  
+QPDF makes use of zlib and jpeg libraries for its functionality. These packages can be downloaded separately from their own download locations, or they can be downloaded in the external-libs area of the qpdf download site.
  
-Licensing terms of embedded software
-====================================
-
-QPDF makes use of zlib and jpeg libraries for its functionality. These
-packages can be downloaded separately from their own download
-locations, or they can be downloaded in the external-libs area of the
-qpdf download site.
-
-The Rijndael encryption implementation used as the basis for AES
-encryption and decryption support comes from Philip J. Erdelsky's
-public domain implementation.  The files libqpdf/rijndael.cc and
-libqpdf/qpdf/rijndael.h remain in the public domain.  They were
-obtained from
-
-  http://www.efgh.com/software/rijndael.htm
-  http://www.efgh.com/software/rijndael.txt
+The Rijndael encryption implementation used as the basis for AES encryption and decryption support comes from Philip J. Erdelsky's public domain implementation.  The files `libqpdf/rijndael.cc` and `libqpdf/qpdf/rijndael.h` remain in the public domain.  They were obtained from
+* http://www.efgh.com/software/rijndael.htm
+* http://www.efgh.com/software/rijndael.txt
  
 The embedded sha2 code comes from sphlib 3.0
-
-  http://www.saphir2.com/sphlib/
+* http://www.saphir2.com/sphlib/
  
 That code has the following license:
-
+  ```
   Copyright (c) 2007-2011  Projet RNRT SAPHIR
  
   Permission is hereby granted, free of charge, to any person obtaining
@@ -74,166 +43,59 @@ That code has the following license:
   CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
   TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
   SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+  ```
  
+# Building from a pristine checkout
  
-Building from a pristine checkout
-=================================
-
-When building qpdf from a pristine checkout from version control,
-documentation and automatically generated files are not present.
-Building on Windows from a pristine checkout is not guaranteed to work
-because of issues running autoconf; see README-windows.md for how to
-handle this.  For UNIX and UNIX-like systems, you must have some
-addditional tools installed to build from the source repository.  To
-do this, you should run
+When building qpdf from a pristine checkout from version control, documentation and automatically generated files are not present. Building on Windows from a pristine checkout is not guaranteed to work because of issues running autoconf; see [README-windows.md](README-windows.md) for how to handle this.  For UNIX and UNIX-like systems, you must have some addditional tools installed to build from the source repository.  To do this, you should run
  
+```
 ./autogen.sh
 ./configure --enable-doc-maintenance
 make
 make install
+```
  
-If you don't have Apache fop and the docbook stylesheets installed,
-you won't be able to build documentation.  You can omit
---enable-doc-maintenance and produce working qpdf software that passes
-its test suite, but make install will fail because the documentation
-files won't exist.  Depending on your purposes, you can either work
-around this or grab the docs from a source distribution.
-
+If you don't have Apache fop and the docbook stylesheets installed, you won't be able to build documentation.  You can omit `--enable-doc-maintenance` and produce working qpdf software that passes its test suite, but make install will fail because the documentation files won't exist.  Depending on your purposes, you can either work around this or grab the docs from a source distribution.
  
-Building from source distribution on UNIX/Linux
-===============================================
+# Building from source distribution on UNIX/Linux
  
 For UNIX and UNIX-like systems, you can usually get by with just
  
+```
 ./configure
 make
 make install
+```
+
+Packagers may set DESTDIR, in which case make install will install inside of DESTDIR, as is customary with many packages.  For more detailed general information, see the "INSTALL" file in this directory.  If you are already accustomed to building and installing software that uses autoconf, there's nothing new for you in the INSTALL file. Note that qpdf uses `autoconf` but not `automake`. We have our own system of Makefiles that allows cross-directory dependencies, doesn't use recursive make, and works better on non-UNIX platforms.
+
+# Building on Windows
+
+QPDF is known to build and pass its test suite with mingw (latest version tested: gcc 7.2.0), mingw64 (latest version tested: 7.2.0) and Microsoft Visual C++ 2015, both 32-bit and 64-bit versions.  MSYS2 is required to build as well in order to get make and other related tools.  See [README-windows.md](README-windows.md) for details on how to build under Windows.
+
+# Additional Notes on Build
+
+QPDF's build system, inspired by [abuild](http://www.abuild.org), can optionally use its own built-in rules rather than using libtool and obeying the compiler specified with configure.  This can be enabled by passing `--with-buildrules=buildrules` where buildrules corresponds to one of the `.mk` files (other than `rules.mk`) in the make directory. This should never be necessary on a UNIX system, but may be necessary on a Windows system.  See [README-windows.md](README-windows.md) for details.  There is a `gcc-linux.mk` file enable `gcc-linux` build rules, but it is intended to help test the build system; Linux users should build with the `libtools` rules, which are enabled by default.
+
+The QPDF package provides some executables and a software library.  A user manual can be found in the "doc" directory.  The docbook sources to the user manual can be found in the `manual` directory.
+
+The software library is just `libqpdf`, and all the header files are in the `qpdf` subdirectories of `include` and `libqpdf`. If you link statically with `-lqpdf`, then you will also need to link with `-lz` and `-ljpeg`. The shared qpdf library is linked with `-lz` and `-ljpeg`, none of qpdf's public header files directly include files from `libz`, and only `Pl_DCT.hh` includes files from `libjpeg`, so for most cases, qpdf's development files are self contained. If you need to use `Pl_DCT` in your application code, you will need to have the header files for some libjpeg distribution in your include path.
+
+To learn about using the library, please read comments in the header files in `include/qpdf`, especially `QPDF.hh`, `QPDFObjectHandle.hh`, and
+`QPDFWriter.hh`. These are the best sources of documentation on the API.  You can also study the code of `qpdf/qpdf.cc`, which exercises most of the public interface.  There are additional example programs in the examples directory.  Reading all the source files in the `qpdf` directory (including the qpdf command-line tool and some test drivers) along with the code in the examples directory will give you a complete picture of every aspect of the public interface.
+
+# Additional Notes on Test Suite
+
+By default, slow tests and tests that require dependencies beyond those needed to build qpdf are disabled.  Slow tests include image comparison tests and large file tests.  Image comparison tests can be enabled by passing `--enable-test-compare-images` to ./configure.  This was on by default in qpdf versions prior to 3.0, but is now off by default.  Large file tests can be enabled by passing `--with-large-file-test-path=path` to `./configure` or by setting the `QPDF_LARGE_FILE_TEST_PATH` environment variable.  On Windows, this should be a Windows path.  Run `./configure --help` for additional options.  The test suite provides nearly full coverage even without these tests.  Unless you are making deep changes to the library that would impact the contents of the generated PDF files or testing this on a new platform for the first time, there is no real reason to run these tests.  If you're just running the test suite to make sure that qpdf works for your build, the default tests are adequate.  The configure rules for these tests do nothing other than setting variables in `autoconf.mk`, so you can feel free to turn these on and off directly in `autoconf.mk` rather than rerunning configure.
+
+If you are packaging qpdf for a distribution and preparing a build that is run by an autobuilder, you may want to add the `--enable-show-failed-test-output` to configure options.  This way, if the test suite fails, test failure detail will be included in the build output.  Otherwise, you will have to have access to the `qtest.log` file from the build to view test failures.  The debian packages for qpdf enable this option.
+
+# Random Number Generation
+
+By default, when `qpdf` detects either the Windows cryptography API or the existence of `/dev/urandom`, `/dev/arandom`, or `/dev/random`, it uses them to generate cryptography secure random numbers.  If none of these conditions are true, the build will fail with an error.  This behavior can be modified in several ways:
+* If you configure with `--disable-os-secure-random` or define `SKIP_OS_SECURE_RANDOM`, qpdf will not attempt to use Windows cryptography or the random device.  You must either supply your own random data provider or allow use of insecure random numbers.
+* If you configure qpdf with the `--enable-insecure-random` option or define `USE_INSECURE_RANDOM`, qpdf will try insecure random numbers if OS-provided secure random numbers are disabled.  This is not a fallback.  In order for insecure random numbers to be used, you must also disable OS secure random numbers since, otherwise, failure to find OS secure random numbers is a compile error.  The insecure random number source is stdlib's `random()` or `rand()` calls. These random numbers are not cryptography secure, but the qpdf library is fully functional using them.  Using non-secure random numbers means that it's easier in some cases to guess encryption keys.  If you're not generating encrypted files, there's no advantage to using secure random numbers.
+* In all cases, you may supply your own random data provider.  To do this, derive a class from `qpdf/RandomDataProvider` (since version 5.1.0) and call `QUtil::setRandomDataProvider` before you create any `QPDF` objects.  If you supply your own random data provider, it will always be used even if support for one of the other random data providers is compiled in.  If you wish to avoid any possibility of your build of qpdf from using anything but a user-supplied random data provider, you can define `SKIP_OS_SECURE_RANDOM` and not `USE_INSECURE_RANDOM`.  In this case, qpdf will throw a runtime error if any attempt is made to generate random numbers and no random data provider has been supplied.
  
-Packagers may set DESTDIR, in which case make install will install
-inside of DESTDIR, as is customary with many packages.  For more
-detailed general information, see the "INSTALL" file in this
-directory.  If you are already accustomed to building and installing
-software that uses autoconf, there's nothing new for you in the
-INSTALL file.
-
-
-Building on Windows
-===================
-
-QPDF is known to build and pass its test suite with mingw (latest
-version tested: gcc 4.6.2), mingw64 (latest version tested: 4.7.0) and
-Microsoft Visual C++ 2010, both 32-bit and 64-bit versions.  MSYS plus
-ActiveState Perl is required to build as well in order to get make
-and other related tools.  See README-windows.md for details on how to
-build under Windows, see README-windows.md.
-
-
-Additional Notes on Build
-=========================
-
-QPDF's build system, inspired by abuild (http://www.abuild.org), can
-optionally use its own built-in rules rather than using libtool and
-obeying the compiler specified with configure.  This can be enabled by
-passing --with-buildrules=buildrules where buildrules corresponds to
-one of the .mk files (other than rules.mk) in the make directory.
-This should never be necessary on a UNIX system, but may be necessary
-on a Windows system.  See README-windows.md for details.  There is a
-gcc-linux.mk file enable "gcc-linux" build rules, but it is intended
-to help test the build system; Linux users should build with the
-"libtools" rules, which are enabled by default.
-
-The QPDF package provides some executables and a software library.  A
-user's manual can be found in the "doc" directory.  The docbook
-sources to the user's manual can be found in the "manual" directory.
-
-The software library is just libqpdf, and all the header files are in
-the qpdf subdirectory. If you link statically with -lqpdf, then you
-will also need to link with -lz and -ljpeg. The shared qpdf library is
-linked with -lz and -ljpeg, none of qpdf's public header files
-directly include files from libz, and only Pl_DCT.hh includes files
-from libjpeg, so for most cases, qpdf's development files are self
-contained. If you need to use Pl_DCT in your application code, you
-will need to have the header files for some libjpeg distribution in
-your include path.
-
-To learn about using the library, please read comments in the header
-files in include/qpdf, especially QPDF.hh, QPDFObjectHandle.hh, and
-QPDFWriter.hh.  You can also study the code of qpdf/qpdf.cc, which
-exercises most of the public interface.  There are additional example
-programs in the examples directory.  Reading all the source files in
-the qpdf directory (including the qpdf command-line tool and some test
-drivers) along with the code in the examples directory will give you a
-complete picture of every aspect of the public interface.
-
-
-Additional Notes on Test Suite
-==============================
-
-By default, slow tests are disabled.  Slow tests include image
-comparison tests and large file tests.  Image comparison tests can be
-enabled by passing --enable-test-compare-images to ./configure.  This
-was on by default in qpdf versions prior to 3.0, but is now off by
-default.  Large file tests can be enabled by passing
---with-large-file-test-path=path to ./configure or by setting the
-QPDF_LARGE_FILE_TEST_PATH environment variable.  On Windows, this
-should be a Windows path.  Run ./configure --help for additional
-options.  The test suite provides nearly full coverage even without
-these tests.  Unless you are making deep changes to the library that
-would impact the contents of the generated PDF files or testing this
-on a new platform for the first time, there is no real reason to run
-these tests.  If you're just running the test suite to make sure that
-qpdf works for your build, the default tests are adequate.  The
-configure rules for these tests do nothing other than setting
-variables in autoconf.mk, so you can feel free to turn these on and
-off directly in autoconf.mk rather than rerunning configure.
-
-If you are packaging qpdf for a distribution and preparing a build
-that is run by an autobuilder, you may want to add the
---enable-show-failed-test-output to configure options.  This way, if
-the test suite fails, test failure detail will be included in the
-build output.  Otherwise, you will have to have access to the
-qtest.log file from the build to view test failures.  The debian
-packages for qpdf enable this option, for example.
-
-
-Random Number Generation
-========================
-
-By default, when the qpdf detects either the Windows cryptography API
-or the existence of /dev/urandom, /dev/arandom, or /dev/random, it
-uses them to generate cryptography secure random numbers.  If none of
-these conditions are true, the build will fail with an error.  This
-behavior can be modified in several ways:
-
- * If you configure with --disable-os-secure-random or define
-   SKIP_OS_SECURE_RANDOM, qpdf will not attempt to use Windows
-   cryptography or the random device.  You must either supply your own
-   random data provider or allow use of insecure random numbers.
-
- * If you configure qpdf with the --enable-insecure-random option or
-   define USE_INSECURE_RANDOM, qpdf will try insecure random numbers
-   if OS-provided secure random numbers are disabled.  This is not a
-   fallback.  In order for insecure random numbers to be used, you
-   must also disable OS secure random numbers since, otherwise,
-   failure to find OS secure random numbers is a compile error.  The
-   insecure random number source is stdlib's random() or rand() calls.
-   These random numbers are not cryptography secure, but the qpdf
-   library is fully functional using them.  Using non-secure random
-   numbers means that it's easier in some cases to guess encryption
-   keys.  If you're not generating encrypted files, there's no
-   advantage to using secure random numbers.
-
- * In all cases, you may supply your own random data provider.  To do
-   this, derive a class from qpdf/RandomDataProvider (since 5.1.0) and
-   call QUtil::setRandomDataProvider before you create any QPDF
-   objects.  If you supply your own random data provider, it will
-   always be used even if support for one of the other random data
-   providers is compiled in.  If you wish to avoid any possibility of
-   your build of qpdf from using anything but a user-supplied random
-   data provider, you can define SKIP_OS_SECURE_RANDOM and not
-   USE_INSECURE_RANDOM.  In this case, qpdf will throw a runtime error
-   if any attempt is made to generate random numbers and no random
-   data provider has been supplied.
-
-If you are building qpdf on a platform that qpdf doesn't know how to
-generate secure random numbers on, a patch would be welcome.
+If you are building qpdf on a platform that qpdf doesn't know how to generate secure random numbers on, a patch would be welcome.