Added phlow.sh tool

tools/phlow.sh

@@ -0,0 +1,48 @@
+#!/bin/bash
+# A simple helper tool to reflow the text from the standard input to a given width
+#
+# Usage: cat [file] | phlow.sh [width] [leading_spaces] [trailing_spaces]
+#
+# Created by Luxferre in 2023, released into public domain
+
+TARGET_WIDTH="$1"
+LSPACES="$2"
+TSPACES="$3"
+
+CRLF=$'\r\n'
+SPC=$'\x20'
+
+[[ -z "$TARGET_WIDTH" ]] && TARGET_WIDTH=67 # default page width
+[[ -z "$LSPACES" ]] && LSPACES=0
+[[ -z "$TSPACES" ]] && TSPACES=0
+
+fmtstr="%-$(( LSPACES ))s%-${TARGET_WIDTH}s%-$(( TSPACES ))s${CRLF}" # params: smth, line, smth
+
+while read -rs line; do # fully line-based operation
+  line="${line%%$'\r'}" # remove a trailing CR if it is there
+  llen="${#line}" # get effective line length
+  if (( llen < TARGET_WIDTH )); then # no need to run the logic for smaller lines
+    printf "$fmtstr" '' "$line" ''
+    continue
+  fi
+  lastws=0 # variable to track last whitespace
+  cpos=0 # variable to track current position within the page line
+  pagepos=0 # variable to track the position of new line start
+  outbuf='' # temporary output buffer
+  for ((i=0;i<llen;i++,cpos++)); do # start iterating over characters
+    c="${line:i:1}" # get the current one
+    if (( cpos >= TARGET_WIDTH )); then # we already exceeded the page width
+      (( lastws == 0 )) && lastws=$TARGET_WIDTH # no whitespace encountered here
+      printf "$fmtstr" '' "${outbuf:0:$lastws}" '' # truncate the buffer
+      outbuf=''
+      pagepos=$(( pagepos + lastws ))
+      cpos=0
+      lastws=0
+      i=$pagepos # update current iteration index from the last valid whitespace
+    else # save the whitespace position if found
+      [[ "$c" == "$SPC" ]] && lastws="$cpos"
+      outbuf="${outbuf}${c}" # save the character itself
+    fi
+  done
+  [[ ! -z "$outbuf" ]] && printf "$fmtstr" '' "$outbuf" ''
+done