Zlib for use with Hercules

This repository contains an unmodified copy of Zlib 1.2.11, retrieved October 2017 from http://www.zlib.net/ and stored in the pkg_src subdirectory. This should allow a complete replacement of the pkg_src directory contents when an uplevel upstream Zlib distribution becomes available.

A CMake build script has been added. The CMake script, while based on makefile and and makefile.msc in the upstream Zlib distribution, is specific to Hercules' requirements and only builds a z shared library (.so or .dll). The build script exports targets for the build directory, and for the installation directory if the z shared library is installed. The CMake build for Hercules can import either target. If Zlib is built by the CMake build for Hercules, the build directory target is used.

File Zlib_version.txt line one contains the version of Zlib available in pkg_src.

The CMake build for Hercules will clone and build this repository if Zlib is not installed on the target system, or if the version installed on the target system is older than the version in this repository.

The CMakeLists.txt in the top level directory is a modified version of the original CMakeLists.txt in pkg_src; modifications are licensed using the same BSD license as the unmodified version. Other programming in the top level is copyright by Stephen Orso and is licensed under the Boost license. Documentation and other writing is licensed using the Creative Commons By-SA 4.0 license.

Each file contains specific copyright and license information.

The Zlib package retains its original copyright and license, which can be found at `pkg_src/LICENSE'

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CMake -D Configuration Option Variables

Except for BUILD_TESTING, the configuration options used by the CMake build for Hercules ensure that the Zlib library is built in a manner consistent with the options and target for which Hercules is being built.

• BUILD_TESTING ON | OFF, default is OFF When ON, include the example and example64 executables in the build tree and generate test cases to verify the operation of Zlib
• DEBUG ON | OFF, default is OFF Applicable to single-configuration generators like Makefiles and Ninja. When ON, generate a Debug configuration build script. When OFF, generate a Release script. (The configuration used for multi-configuration generators like Microsoft Visual Studio or Apple Xcode is determined at build time.)
• WINTARGET blank | HOST | DIST | windows-version Applicable when building on Windows. Option windows-version may be any of WinXP364, WinVista, Win7, Win8, Win10 and is case insensitive. When blank or HOST, build for the version of Windows on the host. When DIST, build for the earliest version of Windows supported by Hercules, Windows XP SP3 64-bit. Otherwise build for the Windows version specified.

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Differences from the original CMakeLists.txt

• Normally, only the zlib library is built, as a shared library (libhercz.so or libz1.dll). The static library is not built, as Hercules has no need of it.

• On Windows, a DLL import library is also built.

• On Windows, warning C4267 "'var' : conversion from 'size_t' to 'type', possible loss of data is" suppressed to eliminate noise messages when Hercules builds Zlib.

• If the option BUILD_TESTING is ON (-DBUILD_TESTING=ON), then the example and example64 executables are built and tests added for them. The executable is not included in the package installation.

• A WINTARGET option is added to allow generation for specific versions of the Windows API, with a range from WINXP364 to WIN10.

• The options to build assembly-language versions of selected routines are eliminated. A single attempt to use these routines generated warnings that they were "use at your own risk," and a segment fault upon execution of the sample program.

• The entire unmodified Zlib distribution is stored in the pkg_src directory, and this script reflects that. This should allow a complete replacement the pkg_src directory contents when an uplevel upstream Zlib distribution becomes available.

• On UNIX-like systems, the shared library is not versioned. There is no need, as this build of the package is intended to be used with exactly one application, Hercules, and versioning issues are expected to be addressed as part of updating pkg_src with new upstream code.

• The library installation target is exported to the zlib-targets sub-directory for inclusion by Hercules.

• The library target is also exported from the build tree to allow the Zlib library to be included in a Hercules build by referencing the build directory. If a Hercules builder elects to build this Zlib package, there is no need to install it; the build tree target can be imported.

• The two public headers are copied to the build tree so that the exported build tree target does not make any references to the source tree.

• For targets that support configurations (Windows and mac OS Xcode), only the Release and Debug configurations are supported. The MinSizeRel and RelWithDebInfo configurations are removed if they are present in CMAKE_CONFIGURATION_TYPES.

• On Windows, for both Release and Debug configurations, linker .pdb files are created and included in the install of the library.

CMake 3.4 is the minimum version required to build Zlib because it is the first version to include the boolean WINDOWS_EXPORT_ALL_SYMBOLS, which creates the exports file (.def) needed to build DLLs from source that lacks specific __declspec( dllexport ) declarations.

   

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This README.md file Copyright © 2017 by Stephen R. Orso.

This work is licensed under the Creative Commons Attribution-ShareAlike 4.0 International License.

To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.