configure

#! /usr/bin/env bash

TMPDIR=`mktemp -d -t tmpXXXXXXXX`
trap "rm -rf $TMPDIR" EXIT

usage() {
    cat >&2 <<EOF
usage: $0 [flags]

Help Options:
  -h, --help                Show help options

Build Configuration:
  --cxx                     C++ compiler that should be used.
  --prefix                  Installation path of the library.
  --enable-debug            Build with debug symbols and without optimizations.
  --disable-debug
  --enable-demos            Build libdrc demos.
  --disable-demos
EOF
    exit 0
}

# Options parsing
# Default values
CXX=g++
PREFIX=/usr/local
DEBUG=n
DEMOS=y
for arg; do
    case $arg in
        "--cxx="*)
            CXX=${arg#*=};;
        "--prefix="*)
            PREFIX=${arg#*=};;
        "--enable-debug")
            DEBUG=y;;
        "--disable-debug")
            DEBUG=n;;
        "--enable-demos")
            DEMOS=y;;
        "--disable-demos")
            DEMOS=n;;
        "-h"|"--help")
            usage;;
        *)
            echo >&2 "error: unknown option $arg"
            usage;;
    esac
done

CXXFLAGS="-fPIC -I include -Wall -Wextra -Wno-unused-parameter -Wno-unused-variable -std=gnu++11 $CXXFLAGS"
if [ x"$DEBUG" = x"y" ]; then
    CXXFLAGS="-g -ggdb3 $CXXFLAGS"
else
    CXXFLAGS="-O2 $CXXFLAGS"
fi

# Libraries detection utils
export PKG_CONFIG_PATH="$PREFIX/lib/pkgconfig:$PKG_CONFIG_PATH"
lib_present() {
    pkg-config --exists $@
}
lib_cflags() {
    pkg-config --cflags $@
}
lib_ldflags() {
    pkg-config --libs $@
}

# Check required dependencies
DEPS="libswscale x264"
for DEP in $DEPS
do
    if lib_present "$DEP"; then
        CXXFLAGS+=$(lib_cflags $DEP)
        LDFLAGS+=" $(lib_ldflags $DEP)"
    else
        echo 2>&1 "error: missing one of the required dependencies ($DEP)"
        exit 1
    fi
done

# Check if the ffmpeg version is recent enough.
cat >$TMPDIR/test.cpp <<EOF
#include <libavutil/pixfmt.h>

int main(void) {
  AVPixelFormat fmt = AV_PIX_FMT_NONE;
  (void)fmt;
  return 0;
}
EOF
if ! $CXX $CXXFLAGS -c $TMPDIR/test.cpp -o $TMPDIR/test.o; then
    echo 2>&1 "error: could not compile a test ffmpeg/libavutil C++ source file"
    echo 2>&1 "error: this usually means your ffmpeg/libav version is not up to date"
    exit 1
fi

# Check if x264 is patched for libdrc support.
cat >$TMPDIR/test.cpp <<EOF
#include <stdint.h>
#include <x264.h>

int main(void) {
  x264_param_t p;
  p.b_drh_mode = 1;
  (void)p;
  return 0;
}
EOF
if ! $CXX $CXXFLAGS -c $TMPDIR/test.cpp -o $TMPDIR/test.o; then
    echo 2>&1 "error: could not compile a test x264 C++ source file"
    echo 2>&1 "error: this usually means pkg-config is not finding the patched x264 version - check PKG_CONFIG_PATH"
    exit 1
fi

# Build demos only if we have the required libs installed
DEMOS_DEPS="gl glu glew sdl"
LDFLAGS_DEMOS=-lpthread
if [ x"$DEMOS" = x"y" ]; then
    for DEMOS_DEP in $DEMOS_DEPS
    do
        if lib_present $DEMOS_DEP; then
            CXXFLAGS+=$(lib_cflags $DEMOS_DEP)
            LDFLAGS_DEMOS+=" $(lib_ldflags $DEMOS_DEP)"
        else
           echo 2>&1 "error: demos cannot be built because one of the dependencies ($DEMOS_DEP) could not be found"
        echo 2>&1 "error: demos build can be disabled with --disable-demos"
        exit 1
        fi
    done
fi

# Show a summary to the user
cat <<EOF
Summary:
  Installation prefix: $PREFIX
  Debug mode: $DEBUG
  Build demos: $DEMOS

Run 'make' to build libdrc.
EOF

# Output generation
cat >Makefile.config <<EOF
PREFIX:=$PREFIX
DEMOS:=$DEMOS
CXX:=$CXX
CXXFLAGS:=$CXXFLAGS
LDFLAGS:=$LDFLAGS
LDFLAGS_DEMOS:=$LDFLAGS_DEMOS
EOF

cp libdrc.pc.in libdrc.pc
sed -i "s,@@PREFIX@@,$PREFIX," libdrc.pc