feat(unitproc/bkshuf):Add bash script like shuf

- Note: bkshuf tends to preserve neighbors in output

diff --git a/unitproc/bkshuf b/unitproc/bkshuf
new file mode 100644 (file)
index 0000000..4bf9f99
--- /dev/null
+++ b/unitproc/bkshuf
@@ -0,0 +1,193 @@
+#!/usr/bin/env bash
+# Desc: Mixes input lines while also preserving some neighbors
+# Usage: cat file | bkshuf arg1
+# Version 0.0.1
+# Depends: bc 1.07.1, GNU Coreutils 8.32 (shuf)
+# Input: var: arg1  initial lines to output
+
+BKSHUF_PARAM_LINEC=1000000;
+BKSHUF_PARAM_GSIZE=25 # lines per group for BKSHUF_PARAM_LINEC lines of input
+
+
+yell() { echo "$0: $*" >&2; } # print script path and all args to stderr
+die() { yell "$*"; exit 111; } # same as yell() but non-zero exit status
+must() { "$@" || die "cannot $*"; } # runs args as command, reports args if command fails
+read_stdin() {
+    # Desc: Consumes stdin; outputs as stdout lines
+    # Input: stdin (consumes)
+    # Output: stdout (newline delimited)
+    # Example: printf "foo\nbar\n" | read_stdin
+    # Depends: GNU bash (version 5.1.16)
+    # Version: 0.0.1
+    local input_stdin output;
+
+    # Store stdin
+    if [[ -p /dev/stdin ]]; then
+        input_stdin="$(cat -)";
+    fi; 
+    
+    # Store as output array elements
+    ## Read in stdin
+    if [[ -n $input_stdin ]]; then
+        while read -r line; do
+            output+=("$line");
+        done < <(printf "%s\n" "$input_stdin");
+    fi;
+
+    # Print to stdout
+    printf "%s\n" "${output[@]}";
+}; # read stdin to stdout lines
+checkInt() {
+    # Desc: Checks if arg is integer
+    # Usage: checkInt arg
+    # Input: arg: integer
+    # Output: - return code 0 (if arg is integer)
+    #         - return code 1 (if arg is not integer)
+    # Example: if ! checkInt $arg; then echo "not int"; fi;
+    # Version: 0.0.1
+    local returnState
+
+    #===Process Arg===
+    if [[ $# -ne 1 ]]; then
+       die "ERROR:Invalid number of arguments:$#";
+    fi;
+    
+    RETEST1='^[0-9]+$'; # Regular Expression to test
+    if [[ ! $1 =~ $RETEST1 ]] ; then
+       returnState="false";
+    else
+       returnState="true";
+    fi;
+
+    #===Determine function return code===
+    if [ "$returnState" = "true" ]; then
+       return 0;
+    else
+       return 1;
+    fi;
+} # Checks if arg is integer
+consume_line() {
+    # Desc: Outputs and destroys line from list_input starting at index ip
+    # Usage: consume_line;
+    # Input: var: list_input  array input lines
+    #        var: lco         int   line count original
+    #        var: lcr         int   line count remaining
+    #        var: ip          int   list_input index pointer
+    # Output: stdout:    a single non-blank element from list_input
+    #         list_input     one element destroyed
+    #         var: lc_out    incremented once
+    local n line;
+
+    n=0; # for tracking progress iterating through remaining list_input
+    ### Loop once through list_input indices until a non-blank line found
+    while [[ $n -le $lco ]]; do
+        #### check if line at ip is blank
+        line="${list_input[$ip]}";
+        if [[ -n $line ]]; then
+            ##### consume line at index ip
+            printf "%s\n" "$line" & # print to output
+            unset "list_input[$ip]"; # destroy line in list_input array
+            ((lc_out++));
+            ((lcr--)); # decrement line count remaining lcr
+            #yell "DEBUG:Consumed line ip:$ip:$line";
+            break;
+        fi;
+        #### increment input index pointer, looping around if necessary
+        if [[ $ip -le $lco ]]; then ((ip++)); else ip=0; fi;
+        #### track progress through list_input
+        ((n++));
+    done;
+}; # consume and output line in list_input array starting at index ip
+decide_read() {
+    # Desc: Decides whether to read another line in list_input array
+    #   by comparing $RANDOM to p_seq_int
+    # Usage:  if decide_read; then something; fi;
+    # Input: var: p_seq_int probability (int [0 32767])
+
+    if [[ $RANDOM -lt $p_seq_int ]]; then
+        return 0;
+    else
+        return 1;
+    fi;
+}; # returns 0 with probability p_seq; 1 otherwise
+
+main() {
+    declare par_l0 par_s0 s_exp s;
+    declare -a list_input;
+
+    # Check positional arguments
+    if [[ $# -gt 0 ]] && ! checkInt "$1"; then
+        die "FATAL:Not an integer:$1";
+    else
+        lc_out_max="$1"; # output line count
+    fi;
+    
+    
+    # store input lines from stdin (like `shuf`)
+    while read -r line; do
+        if [[ -z $line ]]; then continue; fi; # skip blank lines
+        #yell "DEBUG:INPUT:$line";
+        list_input+=("$line");
+    done < <( read_stdin; );
+
+    # calc line count (lc)
+    lc="${#list_input[@]}";
+    #lc="$(printf "%s\n" "${list_input[@]}" | wc -l )";
+    #yell "DEBUG:lc:$lc";
+    #yell "DEBUG:list_input:$(declare -p list_input)";
+
+    # calculate group size s
+    par_l0="$BKSHUF_PARAM_LINEC";
+    par_s0="$BKSHUF_PARAM_GSIZE";
+    s_exp="(( $par_s0 - 1 )/( ( l( $par_l0 ) )^2 ))*(l( $lc ))^2+1";
+    s="$(echo "scale=12; $s_exp" | bc -l)";
+
+    # calculate probabilities p_jump, p_seq
+    p_jump="$(echo "scale=12; 1 / ( $s )" | bc -l)";
+    p_seq="$(echo "scale=12; 1 - $p_jump" | bc -l)";
+    p_seq_int="$(echo "scale=0; ($p_seq * 32767)/1" | bc -l)"; # p_seq as int [0 32767] for $RANDOM range
+
+    # generate output
+    lco="${#list_input[@]}"; # save original input line count
+    lcr="$lco";
+    lc_out="0"; # init output line counter
+    if [[ -z "$lc_out_max" ]]; then lc_out_max="$lco"; fi;    
+    ip="$(shuf -i0-$(( lco - 1 )) -n1)"; # init input index pointer
+    n_loop1="0";
+    #yell "DEBUG:max_blanks:$max_blanks"
+    while [[ $lcr -ge 1 ]] && [[ $lc_out -lt $lc_out_max ]]; do
+        ## Select random unconsumed input line and consume it to output
+        ip="$(shuf -i0-$(( lco - 1 )) -n1)"; # init input index pointer
+        consume_line;
+
+        ## Consume the next sequential line with probability p_seq.
+        while decide_read && [[ $lcr -ge 1 ]] && [[ $lc_out -lt $lc_out_max ]]; do
+            consume_line;
+        done;
+        
+        ((n_loop1++)); # increment jump counter
+    done;
+    #yell "DEBUG:n_loop1:$n_loop1"; # count jumps
+    
+}; # main program
+
+main "$@";
+
+# Author: Steven Baltakatei Sandoval
+# License: GPLv3+
+
+# Dependency information
+
+# bc 1.07.1
+# Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006, 2008, 2012-2017 Free Software Foundation, Inc.
+
+
+# shuf (GNU coreutils) 8.32
+# Copyright (C) 2020 Free Software Foundation, Inc.
+# License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
+# This is free software: you are free to change and redistribute it.
+# There is NO WARRANTY, to the extent permitted by law.
+
+# Written by Paul Eggert.
+
+