CMake/Modules/FindZLIB.cmake

# - Find zlib
# Find the native ZLIB includes and library.
# Once done this will define
#
#  ZLIB_INCLUDE_DIRS   - where to find zlib.h, etc.
#  ZLIB_LIBRARIES      - List of libraries when using zlib.
#  ZLIB_FOUND          - True if zlib found.
#
#  ZLIB_VERSION_STRING - The version of zlib found (x.y.z)
#  ZLIB_VERSION_MAJOR  - The major version of zlib
#  ZLIB_VERSION_MINOR  - The minor version of zlib
#  ZLIB_VERSION_PATCH  - The patch version of zlib
#  ZLIB_VERSION_TWEAK  - The tweak version of zlib
#
# The following variable are provided for backward compatibility
#
#  ZLIB_MAJOR_VERSION  - The major version of zlib
#  ZLIB_MINOR_VERSION  - The minor version of zlib
#  ZLIB_PATCH_VERSION  - The patch version of zlib

#=============================================================================
# Copyright 2001-2009 Kitware, Inc.
#
# Distributed under the OSI-approved BSD License (the "License");
# see accompanying file Copyright.txt for details.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of CMake, substitute the full
#  License text for the above reference.)

FIND_PATH(ZLIB_INCLUDE_DIR zlib.h
    "[HKEY_LOCAL_MACHINE\\SOFTWARE\\GnuWin32\\Zlib;InstallPath]/include"
)

SET(ZLIB_NAMES z zlib zdll)
FIND_LIBRARY(ZLIB_LIBRARY
    NAMES
        ${ZLIB_NAMES}
    PATHS
        "[HKEY_LOCAL_MACHINE\\SOFTWARE\\GnuWin32\\Zlib;InstallPath]/lib"
)
MARK_AS_ADVANCED(ZLIB_LIBRARY ZLIB_INCLUDE_DIR)

IF(ZLIB_INCLUDE_DIR AND EXISTS "${ZLIB_INCLUDE_DIR}/zlib.h")
    FILE(STRINGS "${ZLIB_INCLUDE_DIR}/zlib.h" ZLIB_H REGEX "^#define ZLIB_VERSION \"[^\"]*\"$")

    STRING(REGEX REPLACE "^.*ZLIB_VERSION \"([0-9]+).*$" "\\1" ZLIB_VERSION_MAJOR "${ZLIB_H}")
    STRING(REGEX REPLACE "^.*ZLIB_VERSION \"[0-9]+\\.([0-9]+).*$" "\\1" ZLIB_VERSION_MINOR  "${ZLIB_H}")
    STRING(REGEX REPLACE "^.*ZLIB_VERSION \"[0-9]+\\.[0-9]+\\.([0-9]+).*$" "\\1" ZLIB_VERSION_PATCH "${ZLIB_H}")
    STRING(REGEX REPLACE "^.*ZLIB_VERSION \"[0-9]+\\.[0-9]+\\.[0-9]+\\.([0-9]+).*$" "\\1" ZLIB_VERSION_TWEAK "${ZLIB_H}")

    SET(ZLIB_VERSION_STRING "${ZLIB_VERSION_MAJOR}.${ZLIB_VERSION_MINOR}.${ZLIB_VERSION_PATCH}.${ZLIB_VERSION_TWEAK}")

    SET(ZLIB_MAJOR_VERSION "${ZLIB_VERSION_MAJOR}")
    SET(ZLIB_MINOR_VERSION "${ZLIB_VERSION_MINOR}")
    SET(ZLIB_PATCH_VERSION "${ZLIB_VERSION_PATCH}")
ENDIF()

# handle the QUIETLY and REQUIRED arguments and set ZLIB_FOUND to TRUE if 
# all listed variables are TRUE
INCLUDE(FindPackageHandleStandardArgs)
FIND_PACKAGE_HANDLE_STANDARD_ARGS(ZLIB DEFAULT_MSG ZLIB_INCLUDE_DIR ZLIB_LIBRARY)

# handle the VERSION provided in find_package() command
if(ZLIB_FIND_VERSION)
    if(ZLIB_FIND_VERSION_EXACT AND NOT ${ZLIB_VERSION_STRING} VERSION_EQUAL ${ZLIB_FIND_VERSION})
        message(FATAL_ERROR "ZLIB version found (${ZLIB_VERSION_STRING}) does not match the required one (${ZLIB_FIND_VERSION}), aborting.")
    elseif(${ZLIB_VERSION_STRING} VERSION_LESS ${ZLIB_FIND_VERSION})
        if(ZLIB_FIND_REQUIRED)
            message(FATAL_ERROR "ZLIB version found (${ZLIB_VERSION_STRING}) is less then the minimum required (${ZLIB_FIND_VERSION}), aborting.")
        else(ZLIB_FIND_REQUIRED)
            message("ZLIB version found (${ZLIB_VERSION_STRING}) is less then the minimum required (${ZLIB_FIND_VERSION}), continue without ZLIB support.")
            set(ZLIB_FOUND FALSE)
        endif(ZLIB_FIND_REQUIRED)
    endif()
endif(ZLIB_FIND_VERSION)

IF(ZLIB_FOUND)
    SET(ZLIB_INCLUDE_DIRS ${ZLIB_INCLUDE_DIR})
    SET(ZLIB_LIBRARIES ${ZLIB_LIBRARY})
ENDIF()