#!/bin/ksh
##
## SCRIPT: egrep_like_awk_plusminusNlines
##
##                     in $FEDIR/scripts   where $FEDIR=/apps/nns_com/fea
##
#############################################################################
## PURPOSE: Shows $1 lines both above and below lines which contain a match to
##          the string(s) in $2.  The file being searched is named in $3.
##
##          $1 $2 $3 represent the 3 positional arguments to this script.
##
##          Like 'egrep', the string argument may be sub-strings separated
##          by vertical-bars (|).  Hence, the file can actually be searched
##          for an OR-match, in any record of the file, to the several
##          sub-strings within the string.
##
##          Example string:  'fatal|error|fail|warning'
##
##         'awk' is used to find the match and save/print the N lines
##         above a match line as well as the N lines following, where N = $1.
##
##         This is an 'egrep-like' utility --- except that it shows lines
##         around the match lines --- and does this with 'awk',
##         because 'egrep' is not capable of showing the nearby lines.
#############################################################################
## CALL FORMAT:
##
## $FEDIR/scripts/egrep_like_awk_plusminusNlines <integer> <string> <filename>
##
##  Can test with
##       ./egrep_like_awk_plusminusNlines 3 'tk|tool|DISPLAY' $HOME/test_eegrep
##       ./egrep_like_awk_plusminusNlines 2 'tk|tool|DISPLAY' $HOME/test_eegrep
##       ./egrep_like_awk_plusminusNlines 1 'tk|tool|DISPLAY' $HOME/test_eegrep
##       ./egrep_like_awk_plusminusNlines 0 'tk|tool|DISPLAY' $HOME/test_eegrep
##   and 
##       ./egrep_like_awk_plusminusNlines 6 'tk|tool|DISPLAY' $HOME/test_eegrep
#############################################################################
## CALLED BY: various FEA/CAE/CAD/Viz utility scripts, like
##
##                    $FEDIR/scripts/ddam_find_f06_errs_bygui         
##
#############################################################################
## MAINTENANCE HISTORY:
## Written by : Blaise Montandon 26jul2001 Based on script
##                                         'grep_3lines_around'
##                                                        in $FEDIR/scripts
##                            which is called by 'grep3' in  $FEDIR/scripts.
##                 Also, see /apps/nns_com/fea/Dscrtest/test_awk_like_egrep
## Last Update: Blaise Montandon 26jul2001
#############################################################################

#############################################################################
## Check for input item #1.
#############################################################################

if test "$1" = ""
then
	echo "
INPUT ERROR:
Supply an INTEGER (and a string and a filename) to script $0.

Input: <integer> <string> <filename>

Example: $0  3  'error|warning|core|dump'  /var/adm/SYSLOG

Exiting ...
"
	exit
fi

#############################################################################
## Check for input item #2.
#############################################################################

if test "$2" = ""
then
	echo "
INPUT ERROR:
Supply a string to script $0.

Input: <integer> <string> <filename>

Example: $0  3  'error|warning|core|dump'  /var/adm/SYSLOG

Exiting ...
"
	exit
fi

#############################################################################
## Check for input item #3.
#############################################################################

if test "$3" = ""
then
	echo "
INPUT ERROR:
Supply a filename to script $0.

Input: <integer> <string> <filename>

Example: $0  3  'error|warning|core|dump'  /var/adm/SYSLOG

Exiting ...
"
	exit
fi


#############################################################################
## CALL 'awk' -- with an appropriate awk program -- with file $3 as input. 
## (Output is simply allowed to go to stdout.  The calling utility script
##  can direct stdout into an appropriate file.)
#############################################################################
## 'awk' program (AN EXAMPLE) to
##  write all lines whose first field is different from the previous one.
##
##               $1 != prev { print; prev = $1 }
##  NOTE:
##  This extended-egrep 'eegrep' script is basically
##  a more complex version of this.
#############################################################################

##################################################
## FOR TESTING:
##################################################
#  TEST="YES"
   TEST="NO"

if test "$TEST" = "YES"
then

echo "
*..........................................................
* Lines in file $3
* that match the '|'-separated sub-strings in '$2'
* --- including $1 line(s) above-and-below matches
* --- are shown below.
*..........................................................
*  All lines are preceded by line numbers.
*  An asterisk (*) before a line-number indicates a match.
*..........................................................
"
  # set -x

fi


##################################################
## HERE's the 'awk'.
##################################################

awk  -v N="$1"  -v STRING="$2"  \
'BEGIN  {

   #######################################################
   ## Initialize the N "prev" vars to null.
   ## They are to hold the last N lines read.
   #######################################################
   for ( i = 1 ; i <= N ; i++ )
   {
       prev[i] = ""
   }

   ##################################################
   ## After converting STRING to upper-case,
   ## split the "STRING" into NS "subSTRING"s -- at
   ## occurrences of a vertical bar (|).
   ##################################################

   STRING=toupper(STRING)

   NS=split(STRING,subSTRING,"|")


   ## FOR TESTING:
   #   print NS
   #   print subSTRING[1]
   #   print subSTRING[2]
   #   print subSTRING[3]

   ###################################################
   ## "aftcount" holds the integer N,N-1,...,2,1, or 0
   ## --- representing the number of lines after the
   ## last matched line that still need to be printed.
   ###################################################
   aftcount = 0

   ######################################################
   ## "lastprt" holds the line# of the line last printed.
   ## "lastprt" is reset any time "printf" is called.
   ######################################################
   lastprt = 0

}
#END OF BEGIN
#START OF BODY
{
   ####################################################
   ## IF WE HAVE A MATCH, SUSPEND PRINTING
   ## at N "AFTER-A-MATCH-LINES":
   ## If there is a new match, reset "aftcount" to zero.
   ##            (We do not want to print a line twice.)
   ## We will restart aftcount at N after the new match
   ## line is printed.
   ####################################################
   ## We use "Match" to indicate whether there was a
   ## match to at least one of the subSTRINGs, in the
   ## current line ($0).  Match==1 indicates a match.
   ####################################################

   Match = 0
   UPPER=toupper($0)

   for  ( i = 1 ; i <= NS ; i++ ) {  

       if (  UPPER ~ subSTRING[i] )  { aftcount = 0 ; Match = 1 }

       ## FOR TESTING:
       #  print "subSTRING LOOP:: " subSTRING[i] " aftcount: " aftcount " Match: " Match
   }

   ## FOR TESTING:
   # }" $3
   # exit

   ######################################################
   ## PRINT ONE OF THE N "AFTER-A-MATCH-LINES":
   ## If "aftcount" is non-zero, print the current line.
   ## We had a match up to N lines ago. Decrement "aftcount"
   ## and save the number of the printed line in "lastprt".
   ######################################################

   if ( aftcount != 0 ) {

       printf (" %s : %s \n", NR, $0);

       ## If this is the last of the "aftcount" lines,
       ## print a blank line.
       if ( aftcount == 1 ) {print ""}

       aftcount = aftcount - 1 ;
       lastprt = NR

       ## FOR TESTING:
       #  print "aftcount != 0  CHECK::  aftcount: " aftcount " lastprt: " lastprt
   }

   ## FOR TESTING:
   # }" $3
   # exit


   ######################################################
   ## IF WE HAVE A MATCH, PRINT N-PREV & CURRENT:
   ## If there is a match, print the N previous lines
   ## --- as long as their linenums are greater than
   ## the last-printed line number.  (We do not want
   ## to print a line twice.)
   ##
   ## Then print the current line.  Also set "aftcount"
   ## to N, and save the
   ## number of the matched-printed line in "lastprt".
   ######################################################

   for  ( i = N ; i > 0 ; i-- ) {  

       recnum = NR - i
       if ( Match == 1 && recnum > lastprt ) {
             printf (" %s : %s \n", recnum, prev[i])
       }

       ## FOR TESTING:
       #  print "prev[] PRINT-LOOP::  NR= " NR " recnum= " recnum " i= " i
       #  print "prev[] PRINT-LOOP::  lastprt= " lastprt " prev[i]= " prev[i]
   }

   if ( Match == 1 ) {

       printf ("*%s : %s \n", NR, $0);
       aftcount = N;
       lastprt = NR

       ## FOR TESTING:
       #  print "Match == 1 TEST::  aftcount: " aftcount " lastprt: " lastprt
   }


   ########################################################
   ## Update prev[N], prev[N-1], ... , prev[2], and prev[1]
   ## before reading the next line.
   ########################################################

   for  ( i = N ; i > 1 ; i-- )
   {  
     prev[i] = prev[i-1]
   }

   prev[1] = $0

#END OF BODY
}' $3