1 files changed, 79 insertions, 0 deletions
diff --git a/subprojects/exess/src/exess_config.h b/subprojects/exess/src/exess_config.h
new file mode 100644
index 00000000..4325484a
--- /dev/null
+++ b/subprojects/exess/src/exess_config.h
@@ -0,0 +1,79 @@
+/*
+  Copyright 2021 David Robillard <d@drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+/*
+  Configuration header that defines reasonable defaults at compile time.
+
+  This allows compile-time configuration from the command line (typically via
+  the build system) while still allowing the source to be built without any
+  configuration.  The build system can define EXESS_NO_DEFAULT_CONFIG to disable
+  defaults, in which case it must define things like HAVE_FEATURE to enable
+  features.  The design here ensures that compiler warnings or
+  include-what-you-use will catch any mistakes.
+*/
+
+#ifndef EXESS_CONFIG_H
+#define EXESS_CONFIG_H
+
+// Define version unconditionally so a warning will catch a mismatch
+#define EXESS_VERSION "0.0.1"
+
+#if !defined(EXESS_NO_DEFAULT_CONFIG)
+
+// GCC and clang: __builtin_clz()
+#  ifndef HAVE_BUILTIN_CLZ
+#    if defined(__has_builtin)
+#      if __has_builtin(__builtin_clz)
+#        define HAVE_BUILTIN_CLZ 1
+#      else
+#        define HAVE_BUILTIN_CLZ 0
+#      endif
+#    elif defined(__GNUC__)
+#      define HAVE_BUILTIN_CLZ 1
+#    else
+#      define HAVE_BUILTIN_CLZ 0
+#    endif
+#  endif
+
+// GCC and clang: __builtin_clz()
+#  ifndef HAVE_BUILTIN_CLZLL
+#    if defined(__has_builtin)
+#      if __has_builtin(__builtin_clzll)
+#        define HAVE_BUILTIN_CLZLL 1
+#      else
+#        define HAVE_BUILTIN_CLZLL 0
+#      endif
+#    elif defined(__GNUC__)
+#      define HAVE_BUILTIN_CLZLL 1
+#    else
+#      define HAVE_BUILTIN_CLZLL 0
+#    endif
+#  endif
+
+#endif // !defined(EXESS_NO_DEFAULT_CONFIG)
+
+/*
+  Make corresponding USE_FEATURE defines based on the HAVE_FEATURE defines from
+  above or the command line.  The code checks for these using #if (not #ifdef),
+  so there will be an undefined warning if it checks for an unknown feature,
+  and this header is always required by any code that checks for features, even
+  if the build system defines them all.
+*/
+
+#define USE_BUILTIN_CLZ HAVE_BUILTIN_CLZ
+#define USE_BUILTIN_CLZLL HAVE_BUILTIN_CLZLL
+
+#endif // EXESS_CONFIG_H