AC_INIT(src/google/protobuf-c/protobuf-c.h)
PROTOBUF_C_VERSION=0.9

AM_INIT_AUTOMAKE(protobuf-c, $PROTOBUF_C_VERSION)
PACKAGE=protobuf-c
AC_PROG_CC
AC_PROG_CXX
AC_PROG_LIBTOOL
AC_PATH_PROG(PROTOC, protoc)
AC_CHECK_HEADERS(inttypes.h)

# --- Check for the protobuf library. ---
AC_LANG_PUSH([C++])
AC_CHECK_HEADER(google/protobuf/stubs/common.h,,
                [AC_MSG_ERROR([
ERROR: protobuf headers are required.

You must either install protobuf from google,
or if you have it installed in a custom location
you must add '-Iincludedir' to CXXFLAGS
and '-Llibdir' to LDFLAGS.
])])
pbc_savelibs="$LIBS"
LIBS="$LIBS -lprotoc"
AC_TRY_LINK([#include <google/protobuf/compiler/command_line_interface.h>],
            [google::protobuf::compiler::CommandLineInterface cli;],
	    [],
	    [AC_MSG_ERROR([
ERROR:
protobuf test program failed to link:
perhaps you need to add -Llibdir to your LDFLAGS.])])
LIBS="$pbc_savelibs"
AC_LANG_POP()


dnl  ------ define IS_LITTLE_ENDIAN ------
# We try to use, where possible the headers <endian.h>, <mach/endian.h>,
# and <machine/endian.h>, in that order.  They must define the macros
# __LITTLE_ENDIAN and __BYTE_ORDER.  We structure the test so that if they 
# do NOT define __LITTLE_ENDIAN or __BYTE_ORDER then we will disable
# the little-endian optimizations, so the resulting code should be correct,
# but not as fast, if there's a broken endian.h somewhere.
#
# If none of those headers exist, we fallback on a runtime test.
# TODO: support --with-endianness=[little|big]
knows_endianness=0
AC_CHECK_HEADERS([endian.h], [has_endian_h=1; knows_endianness=1], [has_endian_h=0])
if test $knows_endianness = 1 ; then
  AC_TRY_COMPILE([#include <endian.h>], [
   switch (1) { case __LITTLE_ENDIAN: break;
		case __BYTE_ORDER: break; } ],
    [is_little_endian=0], [is_little_endian=1])
else

  # ------------------ try <mach/endian.h>  ------------------
  AC_CHECK_HEADERS([mach/endian.h], [has_mach_endian_h=1; knows_endianness=1], [has_mach_endian_h=0])
  if test $knows_endianness = 1 ; then
    AC_TRY_COMPILE([#include <mach/endian.h>],[
      switch (1) { case __LITTLE_ENDIAN: break;
		   case __BYTE_ORDER: break; }
			      ],
      [is_little_endian=0], [is_little_endian=1])
  fi
  # ------------------ try <machine/endian.h>  ------------------
  if test $knows_endianness = 0; then
    AC_CHECK_HEADERS([machine/endian.h], [has_machine_endian_h=1; knows_endianness=1], [has_machine_endian_h=0])
    if test $knows_endianness = 1 ; then
      AC_TRY_COMPILE([#include <machine/endian.h>],[
	switch (1) { case __LITTLE_ENDIAN: break;
		     case __BYTE_ORDER: break; }
				],
	[is_little_endian=0], [is_little_endian=1])
    fi
  fi
  if test $knows_endianness = 0; then
    AC_MSG_CHECKING([for little-endianness via runtime check])
    AC_RUN_IFELSE([#include <inttypes.h>
    int main() {
      uint32_t v = 0x01020304;
      return memcmp (&v, "\4\3\2\1", 4) == 0 ? 0 : 1;
    }
    ], [is_little_endian=1; result=yes], [is_little_endian=0; result=no])
    AC_MSG_RESULT($result)
  fi
fi

if test $is_little_endian = 1; then
  echo "Your system IS little-endian" 1>&2
else
  echo "Your system IS NOT little-endian" 1>&2
fi
AC_DEFINE_UNQUOTED(IS_LITTLE_ENDIAN, $is_little_endian)

AC_OUTPUT( Makefile src/Makefile src/test/Makefile pkgwriteinfo )