New utility to tag/stamp image

scripts/image_signing/lib/shflags/shflags

+# $Id: shflags 133 2009-05-10 18:04:51Z kate.ward@forestent.com $
+# vim:et:ft=sh:sts=2:sw=2
+#
+# Copyright 2008 Kate Ward. All Rights Reserved.
+# Released under the LGPL (GNU Lesser General Public License)
+#
+# shFlags -- Advanced command-line flag library for Unix shell scripts.
+# http://code.google.com/p/shflags/
+#
+# Author: kate.ward@forestent.com (Kate Ward)
+#
+# This module implements something like the google-gflags library available
+# from http://code.google.com/p/google-gflags/.
+#
+# FLAG TYPES: This is a list of the DEFINE_*'s that you can do.  All flags take
+# a name, default value, help-string, and optional 'short' name (one-letter
+# name).  Some flags have other arguments, which are described with the flag.
+#
+# DEFINE_string: takes any input, and intreprets it as a string.
+#
+# DEFINE_boolean: typically does not take any argument: say --myflag to set
+#   FLAGS_myflag to true, or --nomyflag to set FLAGS_myflag to false.
+#   Alternately, you can say
+#     --myflag=true  or --myflag=t or --myflag=0  or
+#     --myflag=false or --myflag=f or --myflag=1
+#   Passing an option has the same affect as passing the option once.
+#
+# DEFINE_float: takes an input and intreprets it as a floating point number. As
+#   shell does not support floats per-se, the input is merely validated as
+#   being a valid floating point value.
+#
+# DEFINE_integer: takes an input and intreprets it as an integer.
+#
+# SPECIAL FLAGS: There are a few flags that have special meaning:
+#   --help (or -?)  prints a list of all the flags in a human-readable fashion
+#   --flagfile=foo  read flags from foo.  (not implemented yet)
+#   --              as in getopt(), terminates flag-processing
+#
+# EXAMPLE USAGE:
+#
+#   -- begin hello.sh --
+#   #! /bin/sh
+#   . ./shflags
+#   DEFINE_string name 'world' "somebody's name" n
+#   FLAGS "$@" || exit $?
+#   eval set -- "${FLAGS_ARGV}"
+#   echo "Hello, ${FLAGS_name}."
+#   -- end hello.sh --
+#
+#   $ ./hello.sh -n Kate
+#   Hello, Kate.
+#
+# NOTE: Not all systems include a getopt version that supports long flags. On
+# these systems, only short flags are recognized.
+
+#==============================================================================
+# shFlags
+#
+# Shared attributes:
+#   flags_error: last error message
+#   flags_return: last return value
+#
+#   __flags_longNames: list of long names for all flags
+#   __flags_shortNames: list of short names for all flags
+#   __flags_boolNames: list of boolean flag names
+#
+#   __flags_opts: options parsed by getopt
+#
+# Per-flag attributes:
+#   FLAGS_<flag_name>: contains value of flag named 'flag_name'
+#   __flags_<flag_name>_default: the default flag value
+#   __flags_<flag_name>_help: the flag help string
+#   __flags_<flag_name>_short: the flag short name
+#   __flags_<flag_name>_type: the flag type
+#
+# Notes:
+# - lists of strings are space separated, and a null value is the '~' char.
+
+# return if FLAGS already loaded
+[ -n "${FLAGS_VERSION:-}" ] && return 0
+FLAGS_VERSION='1.0.3'
+
+# return values
+FLAGS_TRUE=0
+FLAGS_FALSE=1
+FLAGS_ERROR=2
+
+# reserved flag names
+FLAGS_RESERVED='ARGC ARGV ERROR FALSE HELP PARENT RESERVED TRUE VERSION'
+
+_flags_debug() { echo "flags:DEBUG $@" >&2; }
+_flags_warn() { echo "flags:WARN $@" >&2; }
+_flags_error() { echo "flags:ERROR $@" >&2; }
+_flags_fatal() { echo "flags:FATAL $@" >&2; }
+
+# specific shell checks
+if [ -n "${ZSH_VERSION:-}" ]; then
+  setopt |grep "^shwordsplit$" >/dev/null
+  if [ $? -ne ${FLAGS_TRUE} ]; then
+    _flags_fatal 'zsh shwordsplit option is required for proper zsh operation'
+    exit ${FLAGS_ERROR}
+  fi
+  if [ -z "${FLAGS_PARENT:-}" ]; then
+    _flags_fatal "zsh does not pass \$0 through properly. please declare' \
+\"FLAGS_PARENT=\$0\" before calling shFlags"
+    exit ${FLAGS_ERROR}
+  fi
+fi
+
+#
+# constants
+#
+
+# getopt version
+__FLAGS_GETOPT_VERS_STD=0
+__FLAGS_GETOPT_VERS_ENH=1
+__FLAGS_GETOPT_VERS_BSD=2
+
+getopt >/dev/null 2>&1
+case $? in
+  0) __FLAGS_GETOPT_VERS=${__FLAGS_GETOPT_VERS_STD} ;;  # bsd getopt
+  2)
+    # TODO(kward): look into '-T' option to test the internal getopt() version
+    if [ "`getopt --version`" = '-- ' ]; then
+      __FLAGS_GETOPT_VERS=${__FLAGS_GETOPT_VERS_STD}
+    else
+      __FLAGS_GETOPT_VERS=${__FLAGS_GETOPT_VERS_ENH}
+    fi
+    ;;
+  *)
+    _flags_fatal 'unable to determine getopt version'
+    exit ${FLAGS_ERROR}
+    ;;
+esac
+
+# getopt optstring lengths
+__FLAGS_OPTSTR_SHORT=0
+__FLAGS_OPTSTR_LONG=1
+
+__FLAGS_NULL='~'
+
+# flag info strings
+__FLAGS_INFO_DEFAULT='default'
+__FLAGS_INFO_HELP='help'
+__FLAGS_INFO_SHORT='short'
+__FLAGS_INFO_TYPE='type'
+
+# flag lengths
+__FLAGS_LEN_SHORT=0
+__FLAGS_LEN_LONG=1
+
+# flag types
+__FLAGS_TYPE_NONE=0
+__FLAGS_TYPE_BOOLEAN=1
+__FLAGS_TYPE_FLOAT=2
+__FLAGS_TYPE_INTEGER=3
+__FLAGS_TYPE_STRING=4
+
+# set the constants readonly
+__flags_constants=`set |awk -F= '/^FLAGS_/ || /^__FLAGS_/ {print $1}'`
+for __flags_const in ${__flags_constants}; do
+  # skip certain flags
+  case ${__flags_const} in
+    FLAGS_HELP) continue ;;
+    FLAGS_PARENT) continue ;;
+  esac
+  # set flag readonly
+  if [ -z "${ZSH_VERSION:-}" ]; then
+    readonly ${__flags_const}
+  else  # handle zsh
+    case ${ZSH_VERSION} in
+      [123].*) readonly ${__flags_const} ;;
+      *) readonly -g ${__flags_const} ;;  # declare readonly constants globally
+    esac
+  fi
+done
+unset __flags_const __flags_constants
+
+#
+# internal variables
+#
+
+__flags_boolNames=' '  # space separated list of boolean flag names
+__flags_longNames=' '  # space separated list of long flag names
+__flags_shortNames=' '  # space separated list of short flag names
+
+__flags_columns=''  # screen width in columns
+__flags_opts=''  # temporary storage for parsed getopt flags
+
+#------------------------------------------------------------------------------
+# private functions
+#
+
+# Define a flag.
+#
+# Calling this function will define the following info variables for the
+# specified flag:
+#   FLAGS_flagname - the name for this flag (based upon the long flag name)
+#   __flags_<flag_name>_default - the default value
+#   __flags_flagname_help - the help string
+#   __flags_flagname_short - the single letter alias
+#   __flags_flagname_type - the type of flag (one of __FLAGS_TYPE_*)
+#
+# Args:
+#   _flags__type: integer: internal type of flag (__FLAGS_TYPE_*)
+#   _flags__name: string: long flag name
+#   _flags__default: default flag value
+#   _flags__help: string: help string
+#   _flags__short: string: (optional) short flag name
+# Returns:
+#   integer: success of operation, or error
+_flags_define()
+{
+  if [ $# -lt 4 ]; then
+    flags_error='DEFINE error: too few arguments'
+    flags_return=${FLAGS_ERROR}
+    _flags_error "${flags_error}"
+    return ${flags_return}
+  fi
+
+  _flags_type_=$1
+  _flags_name_=$2
+  _flags_default_=$3
+  _flags_help_=$4
+  _flags_short_=${5:-${__FLAGS_NULL}}
+
+  _flags_return_=${FLAGS_TRUE}
+
+  # TODO(kward): check for validity of the flag name (e.g. dashes)
+
+  # check whether the flag name is reserved
+  echo " ${FLAGS_RESERVED} " |grep " ${_flags_name_} " >/dev/null
+  if [ $? -eq 0 ]; then
+    flags_error="flag name (${_flags_name_}) is reserved"
+    _flags_return_=${FLAGS_ERROR}
+  fi
+
+  # require short option for getopt that don't support long options
+  if [ ${_flags_return_} -eq ${FLAGS_TRUE} \
+      -a ${__FLAGS_GETOPT_VERS} -ne ${__FLAGS_GETOPT_VERS_ENH} \
+      -a "${_flags_short_}" = "${__FLAGS_NULL}" ]
+  then
+    flags_error="short flag required for (${_flags_name_}) on this platform"
+    _flags_return_=${FLAGS_ERROR}
+  fi
+
+  # check for existing long name definition
+  if [ ${_flags_return_} -eq ${FLAGS_TRUE} ]; then
+    if _flags_itemInList "${_flags_name_}" \
+        ${__flags_longNames} ${__flags_boolNames}
+    then
+      flags_error="flag name ([no]${_flags_name_}) already defined"
+      _flags_warn "${flags_error}"
+      _flags_return_=${FLAGS_FALSE}
+    fi
+  fi
+
+  # check for existing short name definition
+  if [ ${_flags_return_} -eq ${FLAGS_TRUE} \
+      -a "${_flags_short_}" != "${__FLAGS_NULL}" ]
+  then
+    if _flags_itemInList "${_flags_short_}" ${__flags_shortNames}; then
+      flags_error="flag short name (${_flags_short_}) already defined"
+      _flags_warn "${flags_error}"
+      _flags_return_=${FLAGS_FALSE}
+    fi
+  fi
+
+  # handle default value. note, on several occasions the 'if' portion of an
+  # if/then/else contains just a ':' which does nothing. a binary reversal via
+  # '!' is not done because it does not work on all shells.
+  if [ ${_flags_return_} -eq ${FLAGS_TRUE} ]; then
+    case ${_flags_type_} in
+      ${__FLAGS_TYPE_BOOLEAN})
+        if _flags_validateBoolean "${_flags_default_}"; then
+          case ${_flags_default_} in
+            true|t|0) _flags_default_=${FLAGS_TRUE} ;;
+            false|f|1) _flags_default_=${FLAGS_FALSE} ;;
+          esac
+        else
+          flags_error="invalid default flag value '${_flags_default_}'"
+          _flags_return_=${FLAGS_ERROR}
+        fi
+        ;;
+
+      ${__FLAGS_TYPE_FLOAT})
+        if _flags_validateFloat "${_flags_default_}"; then
+          :
+        else
+          flags_error="invalid default flag value '${_flags_default_}'"
+          _flags_return_=${FLAGS_ERROR}
+        fi
+        ;;
+
+      ${__FLAGS_TYPE_INTEGER})
+        if _flags_validateInteger "${_flags_default_}"; then
+          :
+        else
+          flags_error="invalid default flag value '${_flags_default_}'"
+          _flags_return_=${FLAGS_ERROR}
+        fi
+        ;;
+
+      ${__FLAGS_TYPE_STRING}) ;;  # everything in shell is a valid string
+
+      *)
+        flags_error="unrecognized flag type '${_flags_type_}'"
+        _flags_return_=${FLAGS_ERROR}
+        ;;
+    esac
+  fi
+
+  if [ ${_flags_return_} -eq ${FLAGS_TRUE} ]; then
+    # store flag information
+    eval "FLAGS_${_flags_name_}='${_flags_default_}'"
+    eval "__flags_${_flags_name_}_${__FLAGS_INFO_TYPE}=${_flags_type_}"
+    eval "__flags_${_flags_name_}_${__FLAGS_INFO_DEFAULT}=\
+\"${_flags_default_}\""
+    eval "__flags_${_flags_name_}_${__FLAGS_INFO_HELP}=\"${_flags_help_}\""
+    eval "__flags_${_flags_name_}_${__FLAGS_INFO_SHORT}='${_flags_short_}'"
+
+    # append flag name(s) to list of names
+    __flags_longNames="${__flags_longNames}${_flags_name_} "
+    __flags_shortNames="${__flags_shortNames}${_flags_short_} "
+    [ ${_flags_type_} -eq ${__FLAGS_TYPE_BOOLEAN} ] && \
+        __flags_boolNames="${__flags_boolNames}no${_flags_name_} "
+  fi
+
+  flags_return=${_flags_return_}
+  unset _flags_default_ _flags_help_ _flags_name_ _flags_return_ _flags_short_ \
+      _flags_type_
+  [ ${flags_return} -eq ${FLAGS_ERROR} ] && _flags_error "${flags_error}"
+  return ${flags_return}
+}
+
+# Return valid getopt options using currently defined list of long options.
+#
+# This function builds a proper getopt option string for short (and long)
+# options, using the current list of long options for reference.
+#
+# Args:
+#   _flags_optStr: integer: option string type (__FLAGS_OPTSTR_*)
+# Output:
+#   string: generated option string for getopt
+# Returns:
+#   boolean: success of operation (always returns True)
+_flags_genOptStr()
+{
+  _flags_optStrType_=$1
+
+  _flags_opts_=''
+
+  for _flags_flag_ in ${__flags_longNames}; do
+    _flags_type_=`_flags_getFlagInfo ${_flags_flag_} ${__FLAGS_INFO_TYPE}`
+    case ${_flags_optStrType_} in
+      ${__FLAGS_OPTSTR_SHORT})
+        _flags_shortName_=`_flags_getFlagInfo \
+            ${_flags_flag_} ${__FLAGS_INFO_SHORT}`
+        if [ "${_flags_shortName_}" != "${__FLAGS_NULL}" ]; then
+          _flags_opts_="${_flags_opts_}${_flags_shortName_}"
+          # getopt needs a trailing ':' to indicate a required argument
+          [ ${_flags_type_} -ne ${__FLAGS_TYPE_BOOLEAN} ] && \
+              _flags_opts_="${_flags_opts_}:"
+        fi
+        ;;
+
+      ${__FLAGS_OPTSTR_LONG})
+        _flags_opts_="${_flags_opts_:+${_flags_opts_},}${_flags_flag_}"
+        # getopt needs a trailing ':' to indicate a required argument
+        [ ${_flags_type_} -ne ${__FLAGS_TYPE_BOOLEAN} ] && \
+            _flags_opts_="${_flags_opts_}:"
+        ;;
+    esac
+  done
+
+  echo "${_flags_opts_}"
+  unset _flags_flag_ _flags_opts_ _flags_optStrType_ _flags_shortName_ \
+      _flags_type_
+  return ${FLAGS_TRUE}
+}
+
+# Returns flag details based on a flag name and flag info.
+#
+# Args:
+#   string: long flag name
+#   string: flag info (see the _flags_define function for valid info types)
+# Output:
+#   string: value of dereferenced flag variable
+# Returns:
+#   integer: one of FLAGS_{TRUE|FALSE|ERROR}
+_flags_getFlagInfo()
+{
+  _flags_name_=$1
+  _flags_info_=$2
+
+  _flags_nameVar_="__flags_${_flags_name_}_${_flags_info_}"
+  _flags_strToEval_="_flags_value_=\"\${${_flags_nameVar_}:-}\""
+  eval "${_flags_strToEval_}"
+  if [ -n "${_flags_value_}" ]; then
+    flags_return=${FLAGS_TRUE}
+  else
+    # see if the _flags_name_ variable is a string as strings can be empty...
+    # note: the DRY principle would say to have this function call itself for
+    # the next three lines, but doing so results in an infinite loop as an
+    # invalid _flags_name_ will also not have the associated _type variable.
+    # Because it doesn't (it will evaluate to an empty string) the logic will
+    # try to find the _type variable of the _type variable, and so on. Not so
+    # good ;-)
+    _flags_typeVar_="__flags_${_flags_name_}_${__FLAGS_INFO_TYPE}"
+    _flags_strToEval_="_flags_type_=\"\${${_flags_typeVar_}:-}\""
+    eval "${_flags_strToEval_}"
+    if [ "${_flags_type_}" = "${__FLAGS_TYPE_STRING}" ]; then
+      flags_return=${FLAGS_TRUE}
+    else
+      flags_return=${FLAGS_ERROR}
+      flags_error="invalid flag name (${_flags_nameVar_})"
+    fi
+  fi
+
+  echo "${_flags_value_}"
+  unset _flags_info_ _flags_name_ _flags_strToEval_ _flags_type_ _flags_value_ \
+      _flags_nameVar_ _flags_typeVar_
+  [ ${flags_return} -eq ${FLAGS_ERROR} ] && _flags_error "${flags_error}"
+  return ${flags_return}
+}
+
+# check for presense of item in a list. passed a string (e.g. 'abc'), this
+# function will determine if the string is present in the list of strings (e.g.
+# ' foo bar abc ').
+#
+# Args:
+#   _flags__str: string: string to search for in a list of strings
+#   unnamed: list: list of strings
+# Returns:
+#   boolean: true if item is in the list
+_flags_itemInList()
+{
+  _flags_str_=$1
+  shift
+
+  echo " ${*:-} " |grep " ${_flags_str_} " >/dev/null
+  if [ $? -eq 0 ]; then
+    flags_return=${FLAGS_TRUE}
+  else
+    flags_return=${FLAGS_FALSE}
+  fi
+
+  unset _flags_str_
+  return ${flags_return}
+}
+
+# Returns the width of the current screen.
+#
+# Output:
+#   integer: width in columns of the current screen.
+_flags_columns()
+{
+  if [ -z "${__flags_columns}" ]; then
+    # determine the value and store it
+    if eval stty size >/dev/null 2>&1; then
+      # stty size worked :-)
+      set -- `stty size`
+      __flags_columns=$2
+    elif eval tput cols >/dev/null 2>&1; then
+      set -- `tput cols`
+      __flags_columns=$1
+    else
+      __flags_columns=80  # default terminal width
+    fi
+  fi
+  echo ${__flags_columns}
+}
+
+# Validate a boolean.
+#
+# Args:
+#   _flags__bool: boolean: value to validate
+# Returns:
+#   bool: true if the value is a valid boolean
+_flags_validateBoolean()
+{
+  _flags_bool_=$1
+
+  flags_return=${FLAGS_TRUE}
+  case "${_flags_bool_}" in
+    true|t|0) ;;
+    false|f|1) ;;
+    *) flags_return=${FLAGS_FALSE} ;;
+  esac
+
+  unset _flags_bool_
+  return ${flags_return}
+}
+
+# Validate a float.
+#
+# Args:
+#   _flags__float: float: value to validate
+# Returns:
+#   bool: true if the value is a valid float
+_flags_validateFloat()
+{
+  _flags_float_=$1
+
+  if _flags_validateInteger ${_flags_float_}; then
+    flags_return=${FLAGS_TRUE}
+  else
+    flags_return=${FLAGS_TRUE}
+    case ${_flags_float_} in
+      -*)  # negative floats
+        _flags_test_=`expr "${_flags_float_}" : '\(-[0-9][0-9]*\.[0-9][0-9]*\)'`
+        ;;
+      *)  # positive floats
+        _flags_test_=`expr "${_flags_float_}" : '\([0-9][0-9]*\.[0-9][0-9]*\)'`
+        ;;
+    esac
+    [ "${_flags_test_}" != "${_flags_float_}" ] && flags_return=${FLAGS_FALSE}
+  fi
+
+  unset _flags_float_ _flags_test_
+  return ${flags_return}
+}
+
+# Validate an integer.
+#
+# Args:
+#   _flags__integer: interger: value to validate
+# Returns:
+#   bool: true if the value is a valid integer
+_flags_validateInteger()
+{
+  _flags_int_=$1
+
+  flags_return=${FLAGS_TRUE}
+  case ${_flags_int_} in
+    -*)  # negative ints
+      _flags_test_=`expr "${_flags_int_}" : '\(-[0-9][0-9]*\)'`
+      ;;
+    *)  # positive ints
+      _flags_test_=`expr "${_flags_int_}" : '\([0-9][0-9]*\)'`
+      ;;
+  esac
+  [ "${_flags_test_}" != "${_flags_int_}" ] && flags_return=${FLAGS_FALSE}
+
+  unset _flags_int_ _flags_test_
+  return ${flags_return}
+}
+
+# Parse command-line options using the standard getopt.
+#
+# Note: the flag options are passed around in the global __flags_opts so that
+# the formatting is not lost due to shell parsing and such.
+#
+# Args:
+#   @: varies: command-line options to parse
+# Returns:
+#   integer: a FLAGS success condition
+_flags_getoptStandard()
+{
+  flags_return=${FLAGS_TRUE}
+  _flags_shortOpts_=`_flags_genOptStr ${__FLAGS_OPTSTR_SHORT}`
+
+  # check for spaces in passed options
+  for _flags_opt_ in "$@"; do
+    # note: the silliness with the x's is purely for ksh93 on Ubuntu 6.06
+    _flags_match_=`echo "x${_flags_opt_}x" |sed 's/ //g'`
+    if [ "${_flags_match_}" != "x${_flags_opt_}x" ]; then
+      flags_error='the available getopt does not support spaces in options'
+      flags_return=${FLAGS_ERROR}
+      break
+    fi
+  done
+
+  if [ ${flags_return} -eq ${FLAGS_TRUE} ]; then
+    __flags_opts=`getopt ${_flags_shortOpts_} $@ 2>&1`
+    _flags_rtrn_=$?
+    if [ ${_flags_rtrn_} -ne ${FLAGS_TRUE} ]; then
+      _flags_warn "${__flags_opts}"
+      flags_error='unable to parse provided options with getopt.'
+      flags_return=${FLAGS_ERROR}
+    fi
+  fi
+
+  unset _flags_match_ _flags_opt_ _flags_rtrn_ _flags_shortOpts_
+  return ${flags_return}
+}
+
+# Parse command-line options using the enhanced getopt.
+#
+# Note: the flag options are passed around in the global __flags_opts so that
+# the formatting is not lost due to shell parsing and such.
+#
+# Args:
+#   @: varies: command-line options to parse
+# Returns:
+#   integer: a FLAGS success condition
+_flags_getoptEnhanced()
+{
+  flags_return=${FLAGS_TRUE}
+  _flags_shortOpts_=`_flags_genOptStr ${__FLAGS_OPTSTR_SHORT}`
+  _flags_boolOpts_=`echo "${__flags_boolNames}" \
+      |sed 's/^ *//;s/ *$//;s/ /,/g'`
+  _flags_longOpts_=`_flags_genOptStr ${__FLAGS_OPTSTR_LONG}`
+
+  __flags_opts=`getopt \
+      -o ${_flags_shortOpts_} \
+      -l "${_flags_longOpts_},${_flags_boolOpts_}" \
+      -- "$@" 2>&1`
+  _flags_rtrn_=$?
+  if [ ${_flags_rtrn_} -ne ${FLAGS_TRUE} ]; then
+    _flags_warn "${__flags_opts}"
+    flags_error='unable to parse provided options with getopt.'
+    flags_return=${FLAGS_ERROR}
+  fi
+
+  unset _flags_boolOpts_ _flags_longOpts_ _flags_rtrn_ _flags_shortOpts_
+  return ${flags_return}
+}
+
+# Dynamically parse a getopt result and set appropriate variables.
+#
+# This function does the actual conversion of getopt output and runs it through
+# the standard case structure for parsing. The case structure is actually quite
+# dynamic to support any number of flags.
+#
+# Args:
+#   argc: int: original command-line argument count
+#   @: varies: output from getopt parsing
+# Returns:
+#   integer: a FLAGS success condition
+_flags_parseGetopt()
+{
+  _flags_argc_=$1
+  shift
+
+  flags_return=${FLAGS_TRUE}
+
+  if [ ${__FLAGS_GETOPT_VERS} -ne ${__FLAGS_GETOPT_VERS_ENH} ]; then
+    set -- $@
+  else
+    # note the quotes around the `$@' -- they are essential!
+    eval set -- "$@"
+  fi
+
+  # provide user with number of arguments to shift by later
+  # NOTE: the FLAGS_ARGC variable is obsolete as of 1.0.3 because it does not
+  # properly give user access to non-flag arguments mixed in between flag
+  # arguments. Its usage was replaced by FLAGS_ARGV, and it is being kept only
+  # for backwards compatibility reasons.
+  FLAGS_ARGC=`expr $# - 1 - ${_flags_argc_}`
+
+  # handle options. note options with values must do an additional shift
+  while true; do
+    _flags_opt_=$1
+    _flags_arg_=${2:-}
+    _flags_type_=${__FLAGS_TYPE_NONE}
+    _flags_name_=''
+
+    # determine long flag name
+    case "${_flags_opt_}" in
+      --) shift; break ;;  # discontinue option parsing
+
+      --*)  # long option
+        _flags_opt_=`expr "${_flags_opt_}" : '--\(.*\)'`
+        _flags_len_=${__FLAGS_LEN_LONG}
+        if _flags_itemInList "${_flags_opt_}" ${__flags_longNames}; then
+          _flags_name_=${_flags_opt_}
+        else
+          # check for negated long boolean version
+          if _flags_itemInList "${_flags_opt_}" ${__flags_boolNames}; then
+            _flags_name_=`expr "${_flags_opt_}" : 'no\(.*\)'`
+            _flags_type_=${__FLAGS_TYPE_BOOLEAN}
+            _flags_arg_=${__FLAGS_NULL}
+          fi
+        fi
+        ;;
+
+      -*)  # short option
+        _flags_opt_=`expr "${_flags_opt_}" : '-\(.*\)'`
+        _flags_len_=${__FLAGS_LEN_SHORT}
+        if _flags_itemInList "${_flags_opt_}" ${__flags_shortNames}; then
+          # yes. match short name to long name. note purposeful off-by-one
+          # (too high) with awk calculations.
+          _flags_pos_=`echo "${__flags_shortNames}" \
+              |awk 'BEGIN{RS=" ";rn=0}$0==e{rn=NR}END{print rn}' \
+                  e=${_flags_opt_}`
+          _flags_name_=`echo "${__flags_longNames}" \
+              |awk 'BEGIN{RS=" "}rn==NR{print $0}' rn="${_flags_pos_}"`
+        fi
+        ;;
+    esac
+
+    # die if the flag was unrecognized
+    if [ -z "${_flags_name_}" ]; then
+      flags_error="unrecognized option (${_flags_opt_})"
+      flags_return=${FLAGS_ERROR}
+      break
+    fi
+
+    # set new flag value
+    [ ${_flags_type_} -eq ${__FLAGS_TYPE_NONE} ] && \
+        _flags_type_=`_flags_getFlagInfo \
+            "${_flags_name_}" ${__FLAGS_INFO_TYPE}`
+    case ${_flags_type_} in
+      ${__FLAGS_TYPE_BOOLEAN})
+        if [ ${_flags_len_} -eq ${__FLAGS_LEN_LONG} ]; then
+          if [ "${_flags_arg_}" != "${__FLAGS_NULL}" ]; then
+            eval "FLAGS_${_flags_name_}=${FLAGS_TRUE}"
+          else
+            eval "FLAGS_${_flags_name_}=${FLAGS_FALSE}"
+          fi
+        else
+          _flags_strToEval_="_flags_val_=\
+\${__flags_${_flags_name_}_${__FLAGS_INFO_DEFAULT}}"
+          eval "${_flags_strToEval_}"
+          if [ ${_flags_val_} -eq ${FLAGS_FALSE} ]; then
+            eval "FLAGS_${_flags_name_}=${FLAGS_TRUE}"
+          else
+            eval "FLAGS_${_flags_name_}=${FLAGS_FALSE}"
+          fi
+        fi
+        ;;
+
+      ${__FLAGS_TYPE_FLOAT})
+        if _flags_validateFloat "${_flags_arg_}"; then
+          eval "FLAGS_${_flags_name_}='${_flags_arg_}'"
+        else
+          flags_error="invalid float value (${_flags_arg_})"
+          flags_return=${FLAGS_ERROR}
+          break
+        fi
+        ;;
+
+      ${__FLAGS_TYPE_INTEGER})
+        if _flags_validateInteger "${_flags_arg_}"; then
+          eval "FLAGS_${_flags_name_}='${_flags_arg_}'"
+        else
+          flags_error="invalid integer value (${_flags_arg_})"
+          flags_return=${FLAGS_ERROR}
+          break
+        fi
+        ;;
+
+      ${__FLAGS_TYPE_STRING})
+        eval "FLAGS_${_flags_name_}='${_flags_arg_}'"
+        ;;
+    esac
+
+    # handle special case help flag
+    if [ "${_flags_name_}" = 'help' ]; then
+      if [ ${FLAGS_help} -eq ${FLAGS_TRUE} ]; then
+        flags_help
+        flags_error='help requested'
+        flags_return=${FLAGS_FALSE}
+        break
+      fi
+    fi
+
+    # shift the option and non-boolean arguements out.
+    shift
+    [ ${_flags_type_} != ${__FLAGS_TYPE_BOOLEAN} ] && shift
+  done
+
+  # give user back non-flag arguments
+  FLAGS_ARGV=''
+  while [ $# -gt 0 ]; do
+    FLAGS_ARGV="${FLAGS_ARGV:+${FLAGS_ARGV} }'$1'"
+    shift
+  done
+
+  unset _flags_arg_ _flags_len_ _flags_name_ _flags_opt_ _flags_pos_ \
+      _flags_strToEval_ _flags_type_ _flags_val_
+  return ${flags_return}
+}
+
+#------------------------------------------------------------------------------
+# public functions
+#
+
+# A basic boolean flag. Boolean flags do not take any arguments, and their
+# value is either 1 (false) or 0 (true). For long flags, the false value is
+# specified on the command line by prepending the word 'no'. With short flags,
+# the presense of the flag toggles the current value between true and false.
+# Specifying a short boolean flag twice on the command results in returning the
+# value back to the default value.
+#
+# A default value is required for boolean flags.
+#
+# For example, lets say a Boolean flag was created whose long name was 'update'
+# and whose short name was 'x', and the default value was 'false'. This flag
+# could be explicitly set to 'true' with '--update' or by '-x', and it could be
+# explicitly set to 'false' with '--noupdate'.
+DEFINE_boolean() { _flags_define ${__FLAGS_TYPE_BOOLEAN} "$@"; }
+
+# Other basic flags.
+DEFINE_float()   { _flags_define ${__FLAGS_TYPE_FLOAT} "$@"; }
+DEFINE_integer() { _flags_define ${__FLAGS_TYPE_INTEGER} "$@"; }
+DEFINE_string()  { _flags_define ${__FLAGS_TYPE_STRING} "$@"; }
+
+# Parse the flags.
+#
+# Args:
+#   unnamed: list: command-line flags to parse
+# Returns:
+#   integer: success of operation, or error
+FLAGS()
+{
+  # define a standard 'help' flag if one isn't already defined
+  [ -z "${__flags_help_type:-}" ] && \
+      DEFINE_boolean 'help' false 'show this help' 'h'
+
+  # parse options
+  if [ $# -gt 0 ]; then
+    if [ ${__FLAGS_GETOPT_VERS} -ne ${__FLAGS_GETOPT_VERS_ENH} ]; then
+      _flags_getoptStandard "$@"
+    else
+      _flags_getoptEnhanced "$@"
+    fi
+    flags_return=$?
+  else
+    # nothing passed; won't bother running getopt
+    __flags_opts='--'
+    flags_return=${FLAGS_TRUE}
+  fi
+
+  if [ ${flags_return} -eq ${FLAGS_TRUE} ]; then
+    _flags_parseGetopt $# "${__flags_opts}"
+    flags_return=$?
+  fi
+
+  [ ${flags_return} -eq ${FLAGS_ERROR} ] && _flags_fatal "${flags_error}"
+  return ${flags_return}
+}
+
+# This is a helper function for determining the `getopt` version for platforms
+# where the detection isn't working. It simply outputs debug information that
+# can be included in a bug report.
+#
+# Args:
+#   none
+# Output:
+#   debug info that can be included in a bug report
+# Returns:
+#   nothing
+flags_getoptInfo()
+{
+  # platform info
+  _flags_debug "uname -a: `uname -a`"
+  _flags_debug "PATH: ${PATH}"
+
+  # shell info
+  if [ -n "${BASH_VERSION:-}" ]; then
+    _flags_debug 'shell: bash'
+    _flags_debug "BASH_VERSION: ${BASH_VERSION}"
+  elif [ -n "${ZSH_VERSION:-}" ]; then
+    _flags_debug 'shell: zsh'
+    _flags_debug "ZSH_VERSION: ${ZSH_VERSION}"
+  fi
+
+  # getopt info
+  getopt >/dev/null
+  _flags_getoptReturn=$?
+  _flags_debug "getopt return: ${_flags_getoptReturn}"
+  _flags_debug "getopt --version: `getopt --version 2>&1`"
+
+  unset _flags_getoptReturn
+}
+
+# Returns whether the detected getopt version is the enhanced version.
+#
+# Args:
+#   none
+# Output:
+#   none
+# Returns:
+#   bool: true if getopt is the enhanced version
+flags_getoptIsEnh()
+{
+  test ${__FLAGS_GETOPT_VERS} -eq ${__FLAGS_GETOPT_VERS_ENH}
+}
+
+# Returns whether the detected getopt version is the standard version.
+#
+# Args:
+#   none
+# Returns:
+#   bool: true if getopt is the standard version
+flags_getoptIsStd()
+{
+  test ${__FLAGS_GETOPT_VERS} -eq ${__FLAGS_GETOPT_VERS_STD}
+}
+
+# This is effectively a 'usage()' function. It prints usage information and
+# exits the program with ${FLAGS_FALSE} if it is ever found in the command line
+# arguments. Note this function can be overridden so other apps can define
+# their own --help flag, replacing this one, if they want.
+#
+# Args:
+#   none
+# Returns:
+#   integer: success of operation (always returns true)
+flags_help()
+{
+  if [ -n "${FLAGS_HELP:-}" ]; then
+    echo "${FLAGS_HELP}" >&2
+  else
+    echo "USAGE: ${FLAGS_PARENT:-$0} [flags] args" >&2
+  fi
+  if [ -n "${__flags_longNames}" ]; then
+    echo 'flags:' >&2
+    for flags_name_ in ${__flags_longNames}; do
+      flags_flagStr_=''
+      flags_boolStr_=''
+
+      flags_default_=`_flags_getFlagInfo \
+          "${flags_name_}" ${__FLAGS_INFO_DEFAULT}`
+      flags_help_=`_flags_getFlagInfo \
+          "${flags_name_}" ${__FLAGS_INFO_HELP}`
+      flags_short_=`_flags_getFlagInfo \
+          "${flags_name_}" ${__FLAGS_INFO_SHORT}`
+      flags_type_=`_flags_getFlagInfo \
+          "${flags_name_}" ${__FLAGS_INFO_TYPE}`
+
+      [ "${flags_short_}" != "${__FLAGS_NULL}" ] \
+          && flags_flagStr_="-${flags_short_}"
+
+      if [ ${__FLAGS_GETOPT_VERS} -eq ${__FLAGS_GETOPT_VERS_ENH} ]; then
+        [ "${flags_short_}" != "${__FLAGS_NULL}" ] \
+            && flags_flagStr_="${flags_flagStr_},"
+        [ ${flags_type_} -eq ${__FLAGS_TYPE_BOOLEAN} ] \
+            && flags_boolStr_='[no]'
+        flags_flagStr_="${flags_flagStr_}--${flags_boolStr_}${flags_name_}:"
+      fi
+
+      case ${flags_type_} in
+        ${__FLAGS_TYPE_BOOLEAN})
+          if [ ${flags_default_} -eq ${FLAGS_TRUE} ]; then
+            flags_defaultStr_='true'
+          else
+            flags_defaultStr_='false'
+          fi
+          ;;
+        ${__FLAGS_TYPE_FLOAT}|${__FLAGS_TYPE_INTEGER})
+          flags_defaultStr_=${flags_default_} ;;
+        ${__FLAGS_TYPE_STRING}) flags_defaultStr_="'${flags_default_}'" ;;
+      esac
+      flags_defaultStr_="(default: ${flags_defaultStr_})"
+
+      flags_helpStr_="  ${flags_flagStr_}  ${flags_help_} ${flags_defaultStr_}"
+      flags_helpStrLen_=`expr "${flags_helpStr_}" : '.*'`
+      flags_columns_=`_flags_columns`
+      if [ ${flags_helpStrLen_} -lt ${flags_columns_} ]; then
+        echo "${flags_helpStr_}" >&2
+      else
+        echo "  ${flags_flagStr_}  ${flags_help_}" >&2
+        # note: the silliness with the x's is purely for ksh93 on Ubuntu 6.06
+        # because it doesn't like empty strings when used in this manner.
+        flags_emptyStr_="`echo \"x${flags_flagStr_}x\" \
+            |awk '{printf "%"length($0)-2"s", ""}'`"
+        flags_helpStr_="  ${flags_emptyStr_}  ${flags_defaultStr_}"
+        flags_helpStrLen_=`expr "${flags_helpStr_}" : '.*'`
+        if [ ${__FLAGS_GETOPT_VERS} -eq ${__FLAGS_GETOPT_VERS_STD} \
+            -o ${flags_helpStrLen_} -lt ${flags_columns_} ]; then
+          # indented to match help string
+          echo "${flags_helpStr_}" >&2
+        else
+          # indented four from left to allow for longer defaults as long flag
+          # names might be used too, making things too long
+          echo "    ${flags_defaultStr_}" >&2
+        fi
+      fi
+    done
+  fi
+
+  unset flags_boolStr_ flags_default_ flags_defaultStr_ flags_emptyStr_ \
+      flags_flagStr_ flags_help_ flags_helpStr flags_helpStrLen flags_name_ \
+      flags_columns_ flags_short_ flags_type_
+  return ${FLAGS_TRUE}
+}
+
+# Reset shflags back to an uninitialized state.
+#
+# Args:
+#   none
+# Returns:
+#   nothing
+flags_reset()
+{
+  for flags_name_ in ${__flags_longNames}; do
+    flags_strToEval_="unset FLAGS_${flags_name_}"
+    for flags_type_ in \
+        ${__FLAGS_INFO_DEFAULT} \
+        ${__FLAGS_INFO_HELP} \
+        ${__FLAGS_INFO_SHORT} \
+        ${__FLAGS_INFO_TYPE}
+    do
+      flags_strToEval_=\
+"${flags_strToEval_} __flags_${flags_name_}_${flags_type_}"
+    done
+    eval ${flags_strToEval_}
+  done
+
+  # reset internal variables
+  __flags_boolNames=' '
+  __flags_longNames=' '
+  __flags_shortNames=' '
+
+  unset flags_name_ flags_type_ flags_strToEval_
+}