LZ4: try system library first, fallback to builtin

[tinc] / m4 / lz4.m4

diff --git a/m4/lz4.m4 b/m4/lz4.m4
index f112885..9d79d2e 100644 (file)
--- a/m4/lz4.m4
+++ b/m4/lz4.m4
@@ -19,87 +19,58 @@ dnl  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 AC_DEFUN([tinc_LZ4], [
 
   AC_ARG_ENABLE([lz4],
-    AS_HELP_STRING([--disable-lz4], [disable all lz4 compression support])
-  )
+    AS_HELP_STRING([--disable-lz4], [disable lz4 compression support]))
 
   AC_ARG_ENABLE([lz4-builtin],
-    AS_HELP_STRING([--disable-lz4-builtin], [required to link an lz4 library])
-  )
+    AS_HELP_STRING([--disable-lz4-builtin], [do not use lz4 builtin]))
 
-  AC_ARG_WITH(lz4,
-    AS_HELP_STRING([--with-lz4=DIR], [lz4 shared library prefix (eg: /usr/local)]),
-    [lz4="$withval" CPPFLAGS="$CPPFLAGS -I$withval/include" LDFLAGS="$LDFLAGS -L$withval/lib"]
-  )
+  AS_IF([test "x$enable_lz4" != "xno"], [
+    AC_DEFINE(HAVE_LZ4, 1, [enable lz4 compression support])
 
-  AC_ARG_WITH(lz4-include,
-    AS_HELP_STRING([--with-lz4-include=DIR], [lz4 shared header directory]),
-    [lz4_include="$withval" CPPFLAGS="$CPPFLAGS -I$withval"]
-  )
-
-  AC_ARG_WITH(lz4-lib,
-    AS_HELP_STRING([--with-lz4-lib=DIR], [lz4 shared object directory]),
-    [lz4_lib="$withval" LDFLAGS="$LDFLAGS -L$withval"]
-  )
-
-  dnl Calling this early prevents autoconf lint.
-  AM_CONDITIONAL([CONFIGURE_LZ4_BUILTIN], [test "$enable_lz4_builtin" != 'no'])
-
-  AS_IF([test "$enable_lz4" != 'no' -a "$enable_lz4_builtin" != 'no' ], [
-    AC_DEFINE(HAVE_LZ4, 1, [Enable lz4 support.])
-    AC_DEFINE(HAVE_LZ4_BUILTIN, 1, [Enable lz4 builtin.])
-    AC_DEFINE(HAVE_LZ4_STATE, 1, [Enable lz4 external state features.])
-    AC_DEFINE(
-      [LZ4_compress_shim(a, b, c, d)],
-      [LZ4_compress_fast_extState(lz4_wrkmem, a, b, c, d, 0)],
-      [This is the best interface for the lz4 builtin.]
+    AC_ARG_WITH(lz4,
+      AS_HELP_STRING([--with-lz4=DIR], [lz4 shared library prefix (eg: /usr/local)]),
+      [lz4="$withval"
+       CPPFLAGS="$CPPFLAGS-I$withval/include"
+       LDFLAGS="$LDFLAGS -L$withval/lib"]
     )
-  ],[
-    AS_IF([test "$enable_lz4" != 'no'], [
-      AC_CHECK_HEADERS(lz4.h, [
-        AC_DEFINE(LZ4_H, [<lz4.h>], [Location of lz4.h])
 
-        AC_CHECK_LIB(lz4, LZ4_compress_fast_extState, [
-          LIBS="$LIBS -llz4"
-          AC_DEFINE(HAVE_LZ4, 1, [Enable lz4 compression support.])
-          AC_DEFINE(HAVE_LZ4_STATE, 1, [Enable lz4 external state features.])
-          AC_DEFINE(
-            [LZ4_compress_shim(a, b, c, d)],
-            [LZ4_compress_fast_extState(lz4_wrkmem, a, b, c, d, 0)],
-            [The lz4-r129 library interface.]
-          )
-          break
-        ])
-
-        AC_CHECK_LIB(lz4, LZ4_compress_default, [
-          LIBS="$LIBS -llz4"
-          AC_DEFINE(HAVE_LZ4, 1, [Enable lz4 compression support.])
-          AC_DEFINE(
-            [LZ4_compress_shim(a, b, c, d)],
-            [LZ4_compress_default(a, b, c, d)],
-            [The lz4-r128 library interface.]
-          )
-          break
-        ])
+    AC_ARG_WITH(lz4-include,
+      AS_HELP_STRING([--with-lz4-include=DIR], [lz4 shared header directory]),
+      [lz4_include="$withval"
+       CPPFLAGS="$CPPFLAGS -I$withval"]
+    )
 
-        AC_CHECK_LIB(lz4, LZ4_compress_limitedOutput, [
-          LIBS="$LIBS -llz4"
-          AC_DEFINE(HAVE_LZ4, 1, [Enable lz4 compression support.])
-          AC_DEFINE(
-            [LZ4_compress_shim(a, b, c, d)],
-            [LZ4_compress_limitedOutput(a, b, c, d)],
-            [The lz4-r59 library interface.]
-          )
-          AC_MSG_WARN("Using deprecated lz4-r59 interface.")
-          break
-        ])
+    AC_ARG_WITH(lz4-lib,
+      AS_HELP_STRING([--with-lz4-lib=DIR], [lz4 shared object directory]),
+      [lz4_lib="$withval"
+       LDFLAGS="$LDFLAGS -L$withval"]
+    )
 
-      ],[
-        AC_MSG_ERROR("lz4.h header file not found.")
-        break
+    dnl First we check the system copy of the library
+    AS_IF([test "x$enable_lz4_builtin" != 'xyes'], [
+      AC_CHECK_HEADERS(lz4.h, [
+        AC_CHECK_LIB(lz4, LZ4_compress_fast_extState,
+          [lz4_header='<lz4.h>'
+           LIBS="$LIBS -llz4"])
       ])
+    ])
+
+    dnl If it was not found or is too old, fallback to the built-in copy
+    AS_IF([test "x$enable_lz4_builtin" != 'xno' -a "x$lz4_header" = 'x'], [
+      lz4_header='"lib/lz4/lz4.h"'
+      lz4_builtin=1
+      AC_DEFINE(HAVE_LZ4_BUILTIN, 1, [Enable lz4 builtin.])
+    ])
 
+    dnl If the first one failed and the second one is disabled, there's nothing more we can do
+    AS_IF([test "x$lz4_header" = 'x'], [
+      AC_MSG_ERROR("lz4 library was not found and fallback to builtin is disabled.");
     ])
 
   ])
 
+  AC_DEFINE_UNQUOTED(LZ4_H, [$lz4_header], [Location of lz4.h])
+
+  AM_CONDITIONAL([CONFIGURE_LZ4_BUILTIN], [test "x$lz4_builtin" = 'x1'])
+
 ])