Rewrite FindPCRE.cmake

Complete rewrite of FindPCRE.cmake module from scratch;

- Properly allocate both release and debug libraries
- Automatically prefer static libraries if found
- Properly check the set required version and use find_package_handle_standard_Args to throw an error if the version isn't matching or higher than requested

Author: Phatcat

CMakeLists.txt

@@ -123,12 +123,6 @@ include_directories(${ZLIB_INCLUDE_DIR})
 #            PCRE            #
 ##############################
 find_package(PCRE 8.39 REQUIRED)
-include_directories(${PCRE_INCLUDE_DIR})
-option(PCRE_STATIC_LIB "Statically link to PCRE" ON)
-
-if(PCRE_STATIC_LIB)
-  add_definitions(-DPCRE_STATIC)
-endif()
 
 ##############################
 #         Google Test        #

cmake/FindPCRE.cmake

@@ -1,38 +1,104 @@
-# Copyright (C) 2007-2009 LuaDist.
-# Created by Peter Kapec <kapecp@gmail.com>
-# Redistribution and use of this file is allowed according to the terms of the MIT license.
-# For details see the COPYRIGHT file distributed with LuaDist.
-#	Note:
-#		Searching headers and libraries is very simple and is NOT as powerful as scripts
-#		distributed with CMake, because LuaDist defines directories to search for.
-#		Everyone is encouraged to contact the author with improvements. Maybe this file
-#		becomes part of CMake distribution sometimes.
-
-# - Find pcre
-# Find the native PCRE headers and libraries.
+# Copyright (c) 2025 Ember
 #
-# PCRE_INCLUDE_DIRS	- where to find pcre.h, etc.
-# PCRE_LIBRARIES	- List of libraries when using pcre.
-# PCRE_FOUND	- True if pcre found.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+SET(PCRE_POSSIBLE_LIBRARY_NAMES pcre libpcre)
+SET(PCRE_POSSIBLE_LIB_SUFFIX lib)
+SET(PCRE_POSSIBLE_LIBD_SUFFIX debug/lib)
+SET(POSSIBLE_STATICLIB_NAMES pcre.a libpcre.a pcre-static.lib)
 
 # Look for the header file.
-FIND_PATH(PCRE_INCLUDE_DIR NAMES pcre.h)
+FIND_PATH(PCRE_INCLUDE_DIR
+  NAMES pcre.h
+  PATH_SUFFIXES include
+  DOC "pcre include directory")
+
+# Look for the release library.
+FIND_LIBRARY(PCRE_LIBRARY_RELEASE
+  NAMES ${PCRE_POSSIBLE_LIBRARY_NAMES}
+  PATH_SUFFIXES ${PCRE_POSSIBLE_LIB_SUFFIX}
+  DOC "pcre release library")
+
+# Look for the debug library.
+FIND_LIBRARY(PCRE_LIBRARY_DEBUG
+  NAMES ${PCRE_POSSIBLE_LIBRARY_NAMES}
+  PATH_SUFFIXES ${PCRE_POSSIBLE_LIBD_SUFFIX}
+  DOC "pcre debug library")
+
+# Default to shared libraries.
+IF(PCRE_LIBRARY_RELEASE)
+  IF(PCRE_LIBRARY_DEBUG)
+    SET(PCRE_LIBRARY
+      optimized ${PCRE_LIBRARY_RELEASE}
+      debug ${PCRE_LIBRARY_DEBUG}
+      CACHE INTERNAL "PCRE library")
+  ELSE()
+    SET(PCRE_LIBRARY ${PCRE_LIBRARY_RELEASE} CACHE INTERNAL "PCRE library")
+  ENDIF()
+
+  # Extract the directory from the found release library.
+  GET_FILENAME_COMPONENT(PCRE_LIB_DIR "${PCRE_LIBRARY_RELEASE}" DIRECTORY)
+
+  # Check for static release candidate in that directory.
+  FOREACH(candidate ${POSSIBLE_STATICLIB_NAMES})
+    IF(EXISTS "${PCRE_LIB_DIR}/${candidate}")
+      SET(PCRE_LIBRARY_STATIC_RELEASE "${PCRE_LIB_DIR}/${candidate}")
+      BREAK()
+    ENDIF()
+  ENDFOREACH()
+
+  # If a debug build is sought, check for a static debug candidate.
+  IF(PCRE_LIBRARY_DEBUG)
+    FOREACH(candidate ${POSSIBLE_STATICLIB_NAMES})
+      IF(EXISTS "${PCRE_LIB_DIR}/${candidate}")
+        SET(PCRE_LIBRARY_STATIC_DEBUG "${PCRE_LIB_DIR}/${candidate}")
+        BREAK()
+      ENDIF()
+    ENDFOREACH()
+  ENDIF()
 
-# Look for the library.
-FIND_LIBRARY(PCRE_LIBRARY NAMES pcre)
+  # If we found a static release candidate, override the shared one.
+  IF(PCRE_LIBRARY_STATIC_RELEASE)
+    IF(PCRE_LIBRARY_DEBUG AND PCRE_LIBRARY_STATIC_DEBUG)
+      SET(PCRE_LIBRARY
+        optimized "${PCRE_LIBRARY_STATIC_RELEASE}"
+        debug "${PCRE_LIBRARY_STATIC_DEBUG}"
+        CACHE INTERNAL "PCRE library" FORCE)
+    ELSE()
+      SET(PCRE_LIBRARY "${PCRE_LIBRARY_STATIC_RELEASE}" CACHE INTERNAL "PCRE library" FORCE)
+    ENDIF()
+  ENDIF()
+ENDIF()
 
-# Handle the QUIETLY and REQUIRED arguments and set PCRE_FOUND to TRUE if all listed variables are TRUE.
-INCLUDE(FindPackageHandleStandardArgs)
-FIND_PACKAGE_HANDLE_STANDARD_ARGS(PCRE DEFAULT_MSG PCRE_LIBRARY PCRE_INCLUDE_DIR)
+IF(PCRE_LIBRARY_STATIC_RELEASE)
+  MESSAGE(STATUS "Using PCRE static release library")
+ELSE()
+  MESSAGE(STATUS "Using PCRE shared release library")
+ENDIF()
 
-# Copy the results to the output variables.
-IF(PCRE_FOUND)
-	SET(PCRE_LIBRARIES ${PCRE_LIBRARY})
-	SET(PCRE_INCLUDE_DIRS ${PCRE_INCLUDE_DIR})
-ELSE(PCRE_FOUND)
-	SET(PCRE_LIBRARIES)
-	SET(PCRE_INCLUDE_DIRS)
-ENDIF(PCRE_FOUND)
+IF(PCRE_LIBRARY_STATIC_DEBUG)
+  MESSAGE(STATUS "Also using PCRE static debug library")
+ELSEIF(PCRE_LIBRARY_DEBUG)  
+  MESSAGE(STATUS "Also using PCRE shared debug library")
+ENDIF()
 
-MARK_AS_ADVANCED(PCRE_INCLUDE_DIRS PCRE_LIBRARIES)
+# Extract the version from the header and compare it to the required version.
+IF(PCRE_INCLUDE_DIR)
+  SET(_PCRE_VERSION_HEADER "${PCRE_INCLUDE_DIR}/pcre.h")
+  IF(EXISTS "${_PCRE_VERSION_HEADER}")
+    FILE(STRINGS "${_PCRE_VERSION_HEADER}" _PCRE_VERSION_TMP REGEX "#define PCRE_(MAJOR|MINOR)[ \t]+[0-9]+")
+    STRING(REGEX REPLACE ".*#define PCRE_MAJOR[ \t]+([0-9]+).*" "\\1" _PCRE_FOUND_MAJOR "${_PCRE_VERSION_TMP}")
+    STRING(REGEX REPLACE ".*#define PCRE_MINOR[ \t]+([0-9]+).*" "\\1" _PCRE_FOUND_MINOR "${_PCRE_VERSION_TMP}")
+    SET(_PCRE_FOUND_VERSION "${_PCRE_FOUND_MAJOR}.${_PCRE_FOUND_MINOR}")
+    IF(_PCRE_FOUND_VERSION VERSION_GREATER_EQUAL "${PCRE_VERSION}")
+      SET(PCRE_VERSION "${_PCRE_FOUND_VERSION}")
+    ELSE() # The found version is too old; clear PCRE_VERSION so that the handler later will throw an error.
+      UNSET(PCRE_VERSION)
+    ENDIF()
+  ENDIF()
+ENDIF()
 
+# Handle the QUIETLY and REQUIRED arguments and mark PCRE as found if all listed variables are TRUE.
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(PCRE REQUIRED_VARS PCRE_INCLUDE_DIR PCRE_LIBRARY VERSION_VAR PCRE_VERSION)