bash: contains_item function. Check if an item is in an array

contains_item.sh

#############################################################################
# contains_item ${needle} ${haystack[@]}
#############################################################################
contains_item() {
  set +x
  local ITEM=$1
  local LIST=${@:2}

  for ELEM in ${LIST[@]}
  do
    #echo "Scanning for needle:${ITEM}: currently @ ${ELEM}"
    if [ ${ITEM} == ${ELEM} ]; then
      #echo "Found ${ITEM} == ${ELEM}"
      return 0
    fi
  done
  #echo "Did not find ${ITEM}"
  return 1
}
#############################################################################
#
# Example: We want to populate --enable-decoder= and --disable-decoder= flags
# to invoke a ./configure script, the script gives us the list of all decoders available
# we we want to exclude the ones in a given list
# 
# ENABLED_DECODERS=(flv h263 h263i h264 hevc mpeg1video mpeg2video mpeg4 svq1 svq3 vp6 vp8 vp9 wmv1 wmv2 aac ac3 flac mp3 mp3 vorbis wmav1 wmav2 adpcm_g726)
# AVAILABLE_DECODERS=`./configure --list-decoders` # We get all the available decoders
#
# DISABLED_DECODERS_FLAGS="" # We'll store the final decoders to disable here
#
# for DECODER in ${AVAILABLE_DECODERS}
#  do
#    ENCODER_ENABLED=`contains_item ${DECODER} ${ENABLED_DECODERS[@]}`
#    # if we don't find it in the enabled list, we add it.
#    # (Yes, in bash 1 stands for false. functions return 0 when everything went fine as in errors)
#    if [[ ${ENCODER_ENABLED} == 1 ]]; then
#       echo "Disabling not found decoder: ${DECODER}"
#       DISABLED_DECODERS_FLAGS+="--disable-decoder=${DECODER} ";
#    fi
#  done;