Get version information from taglib.h.

This avoids duplication of the version information in both
CMakeLists.txt and taglib.h while keeping the possibility to
use something different from CMake.

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d4469b5dc5cee8215d02f76dd5dee2975be820f6..bae9e2fc5be9efe8338a0cf49e00eff483a97253 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,9 +52,20 @@ if (MSVC AND ENABLE_STATIC_RUNTIME)
   endforeach(flag_var)
 endif()
 
-set(TAGLIB_LIB_MAJOR_VERSION "1")
-set(TAGLIB_LIB_MINOR_VERSION "9")
-set(TAGLIB_LIB_PATCH_VERSION "1")
+# Read version information from file taglib/toolkit/taglib.h into variables
+# TAGLIB_LIB_MAJOR_VERSION, TAGLIB_LIB_MINOR_VERSION, TAGLIB_LIB_PATCH_VERSION.
+foreach(version_part MAJOR MINOR PATCH)
+  set(version_var_name "TAGLIB_${version_part}_VERSION")
+  file(STRINGS taglib/toolkit/taglib.h version_line
+       REGEX "^#define +${version_var_name}")
+  if(NOT version_line)
+    message(FATAL_ERROR "${version_var_name} not found in taglib.h")
+  endif()
+  string(REGEX MATCH "${version_var_name} +([^ ]+)" result ${version_line})
+  set(TAGLIB_LIB_${version_part}_VERSION ${CMAKE_MATCH_1})
+endforeach(version_part)
+# Only used to force cmake rerun when taglib.h changes.
+configure_file(taglib/toolkit/taglib.h ${CMAKE_CURRENT_BINARY_DIR}/taglib.h.stamp)
 
 set(TAGLIB_LIB_VERSION_STRING "${TAGLIB_LIB_MAJOR_VERSION}.${TAGLIB_LIB_MINOR_VERSION}.${TAGLIB_LIB_PATCH_VERSION}")