#!/bin/sh
# simple risu configure script
#
# Copyright (c) 2013 Linaro Limited
# All rights reserved. This program and the accompanying materials
# are made available under the terms of the Eclipse Public License v1.0
# which accompanies this distribution, and is available at
# http://www.eclipse.org/legal/epl-v10.html
#
# Contributors:
#      Claudio Fontana (Linaro) - initial implementation

# Locate the directory where this configure script is
SRCDIR="$(cd "$(dirname "$0")"; pwd)"

# Temporary directory used for files created by this script.
# Like autoconf (and like QEMU) we put this directory in the
# build directory, which means we can just give it a fixed name and
# blow it away when configure is run, and we don't need to jump
# through complicated hoops to delete it when configure exits
# abnormally (it may be useful for debug purposes on an
# abnormal exit).
tmp_dir="config-temp"
rm -rf "$tmp_dir"
mkdir -p "$tmp_dir"
if [ $? -ne 0 ]; then
    echo "ERROR: could not create temporary directory"
    exit 1
fi

compile() {
    $CC $CFLAGS -c -o ${1}.o ${1}.c 2>/dev/null
}

link() {
    $LD $LDFLAGS -l${2} -o ${1} ${1}.o 2>/dev/null
}

check_define() {
    c=${tmp_dir}/check_define_${1}
    cat > ${c}.c <<EOF
#if !defined($1)
#error $1 not defined
#endif
int main(void) { return 0; }
EOF
    compile $c
}

guess_arch() {
    if check_define __aarch64__ ; then
        ARCH="aarch64"
    elif check_define __arm__ ; then
        ARCH="arm"
    elif check_define __i386__ || check_define __x86_64__ ; then
        ARCH="i386"
    elif check_define __m68k__ ; then
        ARCH="m68k"
    elif check_define __powerpc64__ ; then
        ARCH="ppc64"
    elif check_define __s390x__ ; then
        ARCH="s390x"
    else
        echo "This cpu is not supported by risu. Try -h. " >&2
        exit 1
    fi
}

check_type() {
    c=${tmp_dir}/check_type_${1}
    cat > ${c}.c <<EOF
#include <inttypes.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/socket.h>

int main(void) { $1 thisone; return 0; }
EOF
    compile $c
}

check_lib() {
    c=${tmp_dir}/check_lib${1}
    cat > ${c}.c <<EOF
#include <stdint.h>
#include <$2.h>

int main(void) { $3; return 0; }
EOF
    compile $c && link $c $1
}

generate_config() {
    cfg=config.h
    echo "generating config.h..."

    echo "/* config.h - generated by the 'configure' script */" > $cfg
    echo "#ifndef CONFIG_H" >> $cfg
    echo "#define CONFIG_H 1" >> $cfg

    if check_lib z zlib "zlibVersion()"; then
        echo "#define HAVE_ZLIB 1" >> $cfg
        LDFLAGS=-lz
    fi

    echo "#endif /* CONFIG_H */" >> $cfg

    echo "...done"
}

generate_makefilein() {
    m=Makefile.in
    echo "generating Makefile.in..."

    echo "# Makefile.in - generated by the 'configure' script" > $m
    echo "ARCH:=${ARCH}" >> $m
    echo "CC:=${CC}" >> $m
    echo "CPPFLAGS:=${CPPFLAGS}" >> $m
    echo "LDFLAGS:=${LDFLAGS}" >> $m
    echo "AS:=${AS}" >> $m
    echo "OBJCOPY:=${OBJCOPY}" >> $m
    echo "OBJDUMP:=${OBJDUMP}" >> $m
    echo "STATIC:=${STATIC}" >> $m
    echo "SRCDIR:=${SRCDIR}" >> $m
    echo "BUILD_INC:=${BUILD_INC}" >> $m

    echo "...done"
}

usage() {
    cat <<EOF
Usage: [VAR=VALUE]... ./configure [-h|--help] [-s|--static]

  -s/--static - force a static build of risu

To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE.  See below for descriptions of some of the useful variables.

Some influential environment variables:
  CROSS_PREFIX cross-compiler prefix, defaults to gcc and other tools
               prefixed with the given string.

  ARCH         force target architecture instead of trying to detect it.
               Valid values=[arm|aarch64|m68k|ppc64|ppc64le|s390x]

  CC           C compiler command
  CFLAGS       C compiler flags
  CPPFLAGS     C preprocessor flags, e.g. -I<include dir>

  AS           assembler command
  OBJCOPY      object copy utility command
  OBJDUMP      object dump utility command

EOF
}

# STARTUP: entry point
STATIC=""

for opt do
  case "$opt" in
      --help | -h)
          usage;
          exit 0;;
      --static | -s)
          STATIC="-static"
          ;;

  esac
done

CC="${CC-${CROSS_PREFIX}gcc}"
AS="${AS-${CROSS_PREFIX}as}"
LD="${LD-${CROSS_PREFIX}ld}"
OBJCOPY="${OBJCOPY-${CROSS_PREFIX}objcopy}"
OBJDUMP="${OBJDUMP-${CROSS_PREFIX}objdump}"

if test "x${ARCH}" = "x"; then
    guess_arch
fi

# Are we in a separate build tree? If so, link the Makefile
# so that 'make' works.
if test ! -e Makefile || test -s Makefile; then
    echo "linking Makefile..."
    BUILD_INC="-I $(pwd)"
    ln -sf "${SRCDIR}/Makefile" .
fi

generate_config
generate_makefilein

rm -r "$tmp_dir"

echo "type 'make' to start the build"
exit 0