Bash script to merge static libraries together, useable for macOS, iOS, Android and Linux libraries.

merge_static_libs.sh

#! /bin/bash

#
# Usage ./merge_static_libs.sh [--prefix <prefix>] [--ext <ext>] [--indir <indir>] [--target_platform macos|ios|android|linux] [--android_toolchain <toolchain> outlib inlib1 [inlib2] [inlib3] [...]
# <prefix> defaults to 'lib', <ext> defaults to '.a', <indir> defaults to '.'
# <toolchain> defaults to "arm-linux-androideabi". Other options: "aarch64-linux-android", "x86", "x86_64", "mipsel-linux-android", "mips64el-linux-android".
#
#


TMPFILE=/tmp/$$
trap "rm -f $TMPFILE; exit 0" 0 1 2 3 15
OS=`uname -s`
ARCH=`uname -m`

# Defaults.
if [ "$OS" = "Linux" ]
then
    HOST="linux-${ARCH}"
    TARGET='linux'
elif [ "$OS" = "Darwin" ]
then
    HOST="darwin-${ARCH}"
    TARGET='macos'
elif [ "$OS" = "CYGWIN_NT-6.1" ]
then
    HOST="windows-${ARCH}"
    TARGET='windows'
else
    echo "Unsupported host platform." && exit 1
fi
INPATH=${PWD}
LIBPREFIX="lib"
LIBEXT=".a"
TOOLCHAIN="arm-linux-androideabi"

# Parse command line.
while test $# -gt 0
do
    case "$1" in
        --prefix) LIBPREFIX="$2" ; shift
            ;;
        --ext) LIBEXT="$2" ; shift
            ;;
        --indir) INPATH="$2" ; shift
            ;;
        --target_platform) TARGET="$2" ; shift
            ;;
        --android_toolchain) TOOLCHAIN="$2" ; shift
            ;;
        --*) echo "bad option $1"
            ;;
        *)
            if [ -z "${OUT}" ]; then
                OUT="$1"
            else
                LIBS+=("$1")
            fi
            ;;
    esac
    shift
done

if [ -z "${OUT}" ]; then
    echo "No output library specified." && exit 1
fi
if [ ${#LIBS[@]} -eq 0 ]; then
    echo "No input library/libraries specified." && exit 1
fi

# For debugging input.
#echo --prefix ${LIBPREFIX} --ext ${LIBEXT} --indir ${INPATH} --target_platform ${TARGET} ${OUT} ${LIBS[@]} && exit

if [ "${TARGET}" = "android" ] ; then

    if [ -z "${ANDROID_NDK_ROOT}" ]; then
        echo "ANDROID_NDK_ROOT is not set." && exit 1
    fi
    TOOLCHAIN_VERSION="4.9"
    TOOLSBIN=$ANDROID_NDK_ROOT/toolchains/$TOOLCHAIN-$TOOLCHAIN_VERSION/prebuilt/$HOST/$TOOLCHAIN/bin

    echo "CREATE $LIBPREFIX$OUT$LIBEXT" >$TMPFILE
    for lib in ${LIBS[@]}
    do
      echo "ADDLIB $INPATH/$LIBPREFIX$lib$LIBEXT" >>$TMPFILE 
    done
    echo "SAVE" >>$TMPFILE  
    echo "END" >>$TMPFILE  

    $TOOLSBIN/ar -M <$TMPFILE
    $TOOLSBIN/ranlib $LIBPREFIX$OUT$LIBEXT

elif [ "${TARGET}" = "macos" ] || [ "${TARGET}" = "ios" ] ; then

    ARCHS=`lipo -info $INPATH/$LIBPREFIX${LIBS[0]}$LIBEXT | sed -En -e 's/^(Non-|Architectures in the )fat file: .+( is architecture| are): (.*)$/\3/p'`
    if (( $(wc -w <<<"$ARCHS") > 1 )) ; then
        for arch in $ARCHS
        do
            for lib in ${LIBS[@]}
            do
                lipo -extract $arch $INPATH/$LIBPREFIX$lib$LIBEXT -o $LIBPREFIX$lib-$arch$LIBEXT
            done
            INLIBS="${LIBS[*]}"
            INLIBS=`eval echo $LIBPREFIX\{${INLIBS// /,}\}-$arch$LIBEXT`
            libtool -static -o $LIBPREFIX$OUT-$arch$LIBEXT $INLIBS
            rm $INLIBS
        done
        OUTLIBS=`eval echo $LIBPREFIX$OUT-\{${ARCHS// /,}\}$LIBEXT`
        lipo -create $OUTLIBS -o $LIBPREFIX$OUT$LIBEXT
        rm $OUTLIBS
    else
        INLIBS="${LIBS[*]}"
        INLIBS=`eval echo $INPATH/$LIBPREFIX\{${INLIBS// /,}\}$LIBEXT`
        libtool -static -o $LIBPREFIX$OUT$LIBEXT $INLIBS
    fi

elif [ "${TARGET}" = "linux" ] ; then

    echo "CREATE $LIBPREFIX$OUT$LIBEXT" >$TMPFILE
    for lib in ${LIBS[@]}
    do
        echo "ADDLIB $INPATH/$LIBPREFIX$lib$LIBEXT" >>$TMPFILE 
    done
    echo "SAVE" >>$TMPFILE  
    echo "END" >>$TMPFILE  

    ar -M <$TMPFILE
    ranlib $LIBPREFIX$OUT$LIBEXT

fi