forked from HPR/hpr-tools
		
	Added InternetArchive/function_lib.sh
InternetArchive/function_lib.sh: new file; subset of
    '~/bin/function_lib.sh' which is referred to in a number of scripts.
    It contains relevant functions such as 'yes_no' and 'define_colours'.
			
			
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							| @@ -0,0 +1,477 @@ | ||||
| # | ||||
| # Bash Functions for sourcing in scripts. | ||||
| # | ||||
| # This is a copy of some of the functions for HPR project use. | ||||
| # | ||||
| #       ${HOME}/HPR/InternetArchive/function_lib.sh | ||||
| # | ||||
| # Revised: 2024-06-15 18:13:28 | ||||
| # | ||||
|  | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #        NAME:  abs_diff | ||||
| # DESCRIPTION:  Compute the difference between two numbers, returning an | ||||
| #               absolute value | ||||
| #  PARAMETERS:  $1      first number | ||||
| #               $2      second number | ||||
| #     RETURNS:  The absolute value as a string | ||||
| #=============================================================================== | ||||
| function abs_diff { | ||||
|     local p1="${1:?Usage: abs_diff n1 n2}" | ||||
|     local p2="${2:?Usage: abs_diff n1 n2}" | ||||
|  | ||||
|     echo $((p1 >= p2 ? p1 - p2 : p2 - p1)) | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #          NAME:  cleanup_temp | ||||
| #   DESCRIPTION:  Cleanup temporary files in case of a keyboard interrupt | ||||
| #                 (SIGINT) or a termination signal (SIGTERM) and at script | ||||
| #                 exit | ||||
| #    PARAMETERS:  * - names of temporary files to delete | ||||
| #       RETURNS:  Nothing | ||||
| #=============================================================================== | ||||
| function cleanup_temp { | ||||
|     for tmp in "$@"; do | ||||
|         [ -e "$tmp" ] && rm --force "$tmp" | ||||
|     done | ||||
|     exit 0 | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #         NAME: _DEBUG | ||||
| #  DESCRIPTION: Writes one or more messages if in DEBUG mode. Each argument is | ||||
| #               seen as a message and is written on a separate line. | ||||
| #               References the global variable 'DEBUG' which is expected to be | ||||
| #               True if debug output is wanted. | ||||
| #   PARAMETERS: List of messages | ||||
| #      RETURNS: Nothing | ||||
| #=============================================================================== | ||||
| _DEBUG () { | ||||
|     [ "$DEBUG" == 0 ] && return | ||||
|     for msg in "$@"; do | ||||
|         printf 'D> %s\n' "$msg" | ||||
|     done | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #         NAME: yes_no | ||||
| #  DESCRIPTION: Read a Yes or No response from STDIN (only these values are | ||||
| #               accepted) and return a suitable numeric value. | ||||
| #   PARAMETERS: 1 - Prompt string for the read | ||||
| #               2 - Default value (optional) | ||||
| #      RETURNS: 0 for a response of Y or YES, 1 otherwise | ||||
| #=============================================================================== | ||||
| yes_no () { | ||||
|     local prompt="${1:?Usage: yes_no prompt [default]}" | ||||
|     local default="${2^^}" | ||||
|     local ans res | ||||
|  | ||||
|     if [[ $prompt =~ %s ]]; then | ||||
|         if [[ -n $default ]]; then | ||||
|             default=${default:0:1} | ||||
|             # shellcheck disable=SC2059 | ||||
|             # { | ||||
|             case "$default" in | ||||
|                 Y) printf -v prompt "$prompt" "[Y/n]" ;; | ||||
|                 N) printf -v prompt "$prompt" "[y/N]" ;; | ||||
|                 *) echo "Error: ${FUNCNAME[0]} @ line ${BASH_LINENO[0]}: Default must be 'Y' or 'N'" | ||||
|                    exit 1 | ||||
|                    ;; | ||||
|             esac | ||||
|             # } | ||||
|         else | ||||
|             echo "Error: ${FUNCNAME[0]} @ line ${BASH_LINENO[0]}: Default required" | ||||
|             exit 1 | ||||
|         fi | ||||
|     fi | ||||
|  | ||||
|     # | ||||
|     # Loop until a valid input is received | ||||
|     # | ||||
|     while true; do | ||||
|         # | ||||
|         # Read and handle CTRL-D (EOF) | ||||
|         # | ||||
|         read -r -e -p "$prompt" ans | ||||
|         res="$?" | ||||
|         if [[ $res -ne 0 ]]; then | ||||
|             echo "Read aborted" | ||||
|             return 1 | ||||
|         fi | ||||
|  | ||||
|         [ -z "$ans" ] && ans="$default" | ||||
|  | ||||
|         # | ||||
|         # Look for valid replies and return appropriate values. Print an error | ||||
|         # message otherwise and loop around for another go | ||||
|         # | ||||
|         if [[ ${ans^^} =~ ^Y(E|ES)?$ ]]; then | ||||
|             return 0 | ||||
|         elif [[ ${ans^^} =~ ^NO?$ ]]; then | ||||
|             return 1 | ||||
|         else | ||||
|             echo "Invalid reply; please use 'Y' or 'N'" | ||||
|         fi | ||||
|     done | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #         NAME: make_file_list | ||||
| #  DESCRIPTION: Given an array of filenames select from them and make | ||||
| #               an array of choices in a different order if required | ||||
| #   PARAMETERS: 1 - input array name | ||||
| #               2 - output array name | ||||
| #      RETURNS: True (0) if a new list was generated, false (1) otherwise | ||||
| #=============================================================================== | ||||
| make_file_list () { | ||||
|     local -n inarr=${1:?Usage make_file_list input_array out_array} | ||||
|     local -n outarr=${2:?Usage make_file_list input_array out_array} | ||||
|     local i msg prompt range lines choices | ||||
|  | ||||
|     # | ||||
|     # Print the array contents | ||||
|     # | ||||
|     lines="${#inarr[@]}" | ||||
|     for ((i = 0; i < lines; i++)); do | ||||
|         printf '%-2d %s\n' "$((i+1))" "${inarr[$i]}" | ||||
|     done | ||||
|  | ||||
|     msg="Enter a range like '1,2' or '4-7'" | ||||
|     if [[ $lines -eq 1 ]]; then | ||||
|         prompt="1" | ||||
|     else | ||||
|         prompt="1-$lines" | ||||
|         msg+=" (between 1 and $lines)" | ||||
|     fi | ||||
|  | ||||
|     # | ||||
|     # Choose array elements by number where order is significant | ||||
|     # | ||||
|     echo "$msg" | ||||
|     if read_value "Files to add to list: " range "$prompt"; then | ||||
|         # | ||||
|         # If there's a range then parse it and write the relevant elements to the | ||||
|         # target array, otherwise exit with an error | ||||
|         # | ||||
|         if [[ -n "$range" ]]; then | ||||
|             range_parse "$lines" "$range" choices 0 | ||||
|             for i in $choices; do | ||||
|                 outarr+=("${inarr[$((i-1))]}") | ||||
|             done | ||||
|         else | ||||
|             echo "No files chosen; no list created" | ||||
|             return 1 | ||||
|         fi | ||||
|  | ||||
|         return 0 | ||||
|     else | ||||
|         return 1 | ||||
|     fi | ||||
|  | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #          NAME:  range_parse | ||||
| #   DESCRIPTION:  Parse a collection of ranges | ||||
| #    PARAMETERS:  - maximum limit of the range | ||||
| #                 - entered range expression (e.g. 1-3,7,14) | ||||
| #                 - name of variable to receive the result | ||||
| #       RETURNS:  Writes a list of values to the nominated variable | ||||
| #=============================================================================== | ||||
| function range_parse { | ||||
|     local max=${1?range_parse: arg 1 missing} | ||||
|     local range=${2?range:parse: arg2 missing} | ||||
|     local result=${3?range:parse: arg3 missing} | ||||
|     local tosort=${4:-1} | ||||
|  | ||||
|     local selection= | ||||
|  | ||||
|     # | ||||
|     # Turn this off. It affects how some code below behaves | ||||
|     # | ||||
|     set +o nounset | ||||
|  | ||||
|     # | ||||
|     # Remove spaces from the range | ||||
|     # | ||||
|     range=${range// /} | ||||
|  | ||||
|     # | ||||
|     # Check for invalid characters | ||||
|     # | ||||
|     if [[ $range =~ [^0-9,-] ]]; then | ||||
|         echo "Invalid range: $range" | ||||
|         exit | ||||
|     fi | ||||
|  | ||||
|     # | ||||
|     # Slice up the sub-ranges separated by commas and turn all n-m expressions | ||||
|     # into the intermediate values. Trim the trailing space from the | ||||
|     # concatenation. | ||||
|     # | ||||
|     until [[ -z $range ]]; do | ||||
|         if [[ $range =~ [,] ]]; then | ||||
|             item=${range%%,*} | ||||
|             range=${range#*,} | ||||
|         else | ||||
|             item=$range | ||||
|             range= | ||||
|         fi | ||||
|         if [[ $item =~ [-] ]]; then | ||||
|             item=${item//-/ } | ||||
|             if [[ $item =~ ^([0-9]{1,}).([0-9]{1,})$ ]]; then | ||||
|                 # shellcheck disable=SC2086 | ||||
|                 item=$(seq -s' ' $item) | ||||
|             else | ||||
|                 echo "Invalid sequence: ${item/ /-}" | ||||
|                 item= | ||||
|             fi | ||||
|         fi | ||||
|         selection+="$item " | ||||
|     done | ||||
|     selection=${selection%% } | ||||
|  | ||||
|     # | ||||
|     # Check for out of bounds problems, sort values and and make unique | ||||
|     # | ||||
|     if [[ ${#selection} -gt 0 ]]; then | ||||
|         # | ||||
|         # Validate the resulting range | ||||
|         # | ||||
|         declare -a sel err msg | ||||
|         for i in $selection; do | ||||
|             if [[ $i -lt 1 || $i -gt $max ]]; then | ||||
|                 err+=( $i ) | ||||
|             else | ||||
|                 sel+=( $i ) | ||||
|             fi | ||||
|         done | ||||
|  | ||||
|         # | ||||
|         # Report any errors | ||||
|         # | ||||
|         if [[ ${#err[*]} -gt 0 ]]; then | ||||
|             msg=( $(for i in ${err[*]}; do echo $i; done | sort -un) ) | ||||
|             if [[ ${#msg[*]} -gt 1 ]]; then | ||||
|                 printf "Values out of range: %s .. %s\n" ${msg[0]} ${msg[${#msg[*]}-1]} | ||||
|             else | ||||
|                 printf "Value out of range: %s\n" ${msg[0]} | ||||
|             fi | ||||
|         fi | ||||
|  | ||||
|         # | ||||
|         # Rebuild the selection | ||||
|         # | ||||
|         selection= | ||||
|         if [[ ${#sel[*]} -gt 0 ]]; then | ||||
|             if [[ $tosort -eq 1 ]]; then | ||||
|                 selection="$(for i in ${sel[*]}; do echo $i; done | sort -un)" | ||||
|             else | ||||
|                 selection="$(for i in ${sel[*]}; do echo $i; done)" | ||||
|             fi | ||||
|         fi | ||||
|     fi | ||||
|  | ||||
|     # | ||||
|     # Return the result | ||||
|     # | ||||
|     eval $result=\"$selection\" | ||||
|  | ||||
|     return | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #         NAME: pad | ||||
| #  DESCRIPTION: Pad $text to the left with $char characters to length $length | ||||
| #   PARAMETERS: 1 - the text string to pad (no default) | ||||
| #               2 - how long the padded string is to be (default 80) | ||||
| #               3 - the character to pad with (default '-') | ||||
| #      RETURNS: Nothing | ||||
| #=============================================================================== | ||||
| pad () { | ||||
|     local text=${1?Usage: pad text [length] [character]} | ||||
|     local length=${2:-80} | ||||
|     local char=${3:--} | ||||
|  | ||||
|     local line | ||||
|     printf -v line "%0*d%s\n" $((length - ${#text})) 0 "$text" | ||||
|     char=${char:0:1} | ||||
|     echo "${line//0/$char}" | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #         NAME: read_value | ||||
| #  DESCRIPTION: Read a value from STDIN and handle errors. | ||||
| #   PARAMETERS: 1 - Prompt string for the read | ||||
| #               2 - Name of variable to receive the result | ||||
| #               3 - Default value (optional) | ||||
| #      RETURNS: 1 on error, otherwise 0 | ||||
| #=============================================================================== | ||||
| read_value () { | ||||
|     local prompt="${1:?Usage: read_value prompt outputname [default]}" | ||||
|     local outputname="${2:?Usage: read_value prompt outputname [default]}" | ||||
|     local default="${3:-}" | ||||
|     local var | ||||
|  | ||||
|     # | ||||
|     # Make an option for the 'read' if there's a default | ||||
|     # | ||||
|     if [[ -n $default ]]; then | ||||
|         default="-i '$default'" | ||||
|     fi | ||||
|  | ||||
|     # | ||||
|     # Read and handle CTRL-D (EOF). Use 'eval' to deal with the argument being | ||||
|     # a variable | ||||
|     # | ||||
|     eval "read -r -e $default -p '$prompt' var" | ||||
|     res="$?" | ||||
|     if [[ $res -ne 0 ]]; then | ||||
|         echo "Read aborted" | ||||
|         return 1 | ||||
|     fi | ||||
|  | ||||
|     # | ||||
|     # Return the value in the nominated variable | ||||
|     # | ||||
|     eval "$outputname='$var'" | ||||
|     return 0 | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #         NAME: define_colours | ||||
| #  DESCRIPTION: Defines terminal colours | ||||
| #   PARAMETERS: None | ||||
| #      RETURNS: Nothing; justs sets the variables in the namespace | ||||
| #=============================================================================== | ||||
| define_colours () { | ||||
|  | ||||
|     # | ||||
|     # Colour codes | ||||
|     # | ||||
|     red=$(tput setaf 1) | ||||
|     export red | ||||
|     green=$(tput setaf 2) | ||||
|     export green | ||||
|     yellow=$(tput setaf 3) | ||||
|     export yellow | ||||
|     blue=$(tput setaf 4) | ||||
|     export blue | ||||
|     purple=$(tput setaf 5) | ||||
|     export purple | ||||
|     reset=$(tput sgr0) | ||||
|     export reset | ||||
|  | ||||
|     return | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #         NAME: undefine_colours | ||||
| #  DESCRIPTION: Remove all the colour codes from the colour variables | ||||
| #   PARAMETERS: None | ||||
| #      RETURNS: Nothing; justs sets the variables in the namespace | ||||
| #=============================================================================== | ||||
| undefine_colours () { | ||||
|  | ||||
|     # | ||||
|     # Colour codes being removed | ||||
|     # | ||||
|     for code in red green yellow blue purple reset; do | ||||
|         eval "$code=''" | ||||
|         eval "export $code" | ||||
|     done | ||||
|  | ||||
|     return | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #         NAME: coloured | ||||
| #  DESCRIPTION: Write a message with colour codes | ||||
| #   PARAMETERS: 1 - colour name | ||||
| #               2 - message | ||||
| #      RETURNS: Nothing | ||||
| #=============================================================================== | ||||
| coloured () { | ||||
|     local colour="${1:-green}" | ||||
|     local message="${2:-no message}" | ||||
|  | ||||
|     printf '%s%s%s\n' "${!colour}" "$message" "${reset}" | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #         NAME: plural | ||||
| #  DESCRIPTION: Adds an 's' to a word depending on the size of a number (based | ||||
| #               on an example from O'Reilly). Also look at ngettext for a much | ||||
| #               more sophisticated alternative. | ||||
| #   PARAMETERS: 1 - the word to pluralise | ||||
| #               2 - the number used to decide | ||||
| #      RETURNS: Nothing | ||||
| #=============================================================================== | ||||
| plural () { | ||||
|     if [[ $2 -eq 1 || $2 -eq -1 ]]; then | ||||
|         echo "${1}" | ||||
|     else | ||||
|         echo "${1}s" | ||||
|     fi | ||||
| } | ||||
|  | ||||
| #===  FUNCTION  ================================================================ | ||||
| #         NAME: trimpath | ||||
| #  DESCRIPTION: Trim a file path to its last few components for display | ||||
| #   PARAMETERS: $1 - path to trim | ||||
| #               $2 - number of elements to retain | ||||
| #      RETURNS: Trimmed path | ||||
| #=============================================================================== | ||||
| trimpath () { | ||||
|     local path=${1:?Usage: mpath path elements} | ||||
|     local elements=${2:?Usage: mpath path elements} | ||||
|     local -a arr1 arr2 | ||||
|     local result | ||||
|  | ||||
|     # Split the path | ||||
| #     oldifs="$IFS" | ||||
| #     IFS='/' mapfile -d'/' -t arr1 <<<"$path" | ||||
|     IFS='/' read -r -a arr1 <<<"$path" | ||||
| #     IFS="$oldifs" | ||||
|  | ||||
|     if [[ ${#arr1[@]} -gt $elements ]]; then | ||||
|         # Put the last elements in another array | ||||
|         mapfile -t arr2 < <(printf '%s\n' "${arr1[@]: -$elements}") | ||||
|  | ||||
|         # Return the second array interleaved with '/' | ||||
|         result="${arr2[*]/%//}" | ||||
|         result="${result//\/ /\/}" | ||||
|         echo "${result:0:-1}" | ||||
|     else | ||||
|         echo "$path" | ||||
|     fi | ||||
| } | ||||
|  | ||||
| #=============================================================================== | ||||
| #         NAME: stampfile | ||||
| #  DESCRIPTION: Rename a file by adding a timestamp to its name. The timestamp | ||||
| #               is the modification time. It is added at the end by default or | ||||
| #               wherever the caller places a '%s'. Note there are not enough | ||||
| #               error checks to deal with really weird requests :-) | ||||
| #   PARAMETERS: $1 - name of file to rename | ||||
| #               $2 - optional template string | ||||
| #      RETURNS: Nothing | ||||
| #=============================================================================== | ||||
| function stampfile () { | ||||
|     if [[ $# = 0  || $# -gt 2 ]]; then | ||||
|         echo "Usage: ${FUNCNAME[0]} filename [template]" | ||||
|         return | ||||
|     fi | ||||
|     local fname=${1} | ||||
|     local tp=${2:-"${fname}_%s"} | ||||
|     [ -e "$fname" ] || { echo "$fname does not exist"; return; } | ||||
|     # shellcheck disable=SC2059 | ||||
|     new=$(printf "$tp" "$(date -r "$fname" +%Y%m%d_%H%M%S)") | ||||
|     mv "$fname" "$new" || { echo "Unable to mv $fname to $new"; return; } | ||||
|     echo "Renamed $fname to $new" | ||||
| } | ||||
|  | ||||
| # | ||||
| # vim: syntax=sh:ts=8:sw=4:et:tw=78:fo=tcrqn21 | ||||
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