#!/bin/ksh
#*******************************************************************************
#                          KSH PROGRAM
#*******************************************************************************
#
#    PROGRAM ID           : block_grep.ksh
#
#D   DESCRIPTION          : Search for a string and display each occurrence
#D                          including 2 lines before and 4 lines after this
#D                          occurrence (2 and 4 are the defaults and can be
#D                          changed with 3rd and 4th input parameter)
#D
#
#    INPUT PARAMETERS     : $1 - $si_search_string (search string)
#                           $2 - $si_file          (name of the file)
#                           $3 - $si_lines_before  (number of lines to be displayed before)
#                           $4 - $si_lines_after   (number of lines to be displayed after)
#
#    OUTPUT PARAMETERS    : none
#
#
#    INPUT FILES          : $si_file (name of the file)
#
#    OUTPUT FILES         : none
#
#
#    SPECIAL LOGIC NOTES  : none
#
#*******************************************************************************
#                        MODIFICATION LOG
#
#
#    DATE                               SE
#       DESCRIPTION
#    ---------------------------------------------------------------------------
#    Mon Dec 14 09:51:42 CET 2015       (Hajo)
#       initial version
#    ---------------------------------------------------------------------------
#
#*******************************************************************************

#*******************************************************************************
# INITIALIZATION
#*******************************************************************************
export s_parmcount=$#
export s_myname=`basename $0`

export s_parmcount_expected=2

if [[ $s_parmcount -lt $s_parmcount_expected ]]
then
    print -u2 "${s_myname}: USAGE: ${s_myname} <SEARCH_STRING> <FILE_NAME> or"
    print -u2 "                       ${s_myname} <SEARCH_STRING> <FILE_NAME> <LINES_BEFORE> <LINES_AFTER>!"
    exit 1
else
    export si_search_string=$1
    export si_file=$2
    export si_lines_before=$3
    export si_lines_after=$4

    if [ "${si_lines_before}" = "" ]
    then
        export si_lines_before=2
    fi

    if [ "${si_lines_after}" = "" ]
    then
        export si_lines_after=4
    fi

    typeset -i i_line_number=0
    typeset -i i_line_number_before=0
    typeset -i i_occurrence=0
fi


#*******************************************************************************
# FUNCTIONS
#*******************************************************************************
#--------------------------------------------------------------------------------
fun_block_grep () {
#--------------------------------------------------------------------------------
   typeset -i i_linecnt
   i_linecnt=0

   typeset -i i_line_first=0
   typeset -i i_line_last=$(wc -l ${si_file} | awk '{print $1}')

   typeset -i i_line_to_check=$1
   typeset -i i_lines_before=${si_lines_before}
   typeset -i i_lines_after=${si_lines_after}

   typeset -i i_line_start=${i_line_to_check}-${i_lines_before}
   typeset -i i_line_end=${i_line_to_check}+${i_lines_after}


   if [[ ${i_line_start} -lt 0 ]]
   then
      i_line_start=0
   fi


   if [[ ${i_line_end} -gt ${i_line_last} ]]
   then
      i_line_end=${i_line_last}
   fi


   cat ${si_file} |
   while read s_current_line
   do
      let i_linecnt=${i_linecnt}+1

      if [[ ${i_linecnt} -ge ${i_line_start} ]]  && [[ ${i_linecnt} -le ${i_line_end} ]]
      then
         echo "${s_current_line}"
      fi

   done
}


#*******************************************************************************
# MAINLINE
#*******************************************************************************
grep -n ${si_search_string} ${si_file} | sed -e's/\:/ /' | awk '{print $1}' |
while read i_line_number
do
   #echo if [[ ${i_line_number_before} -ne ${i_line_number}-1 ]]
   if [[ ${i_line_number_before} -ne ${i_line_number}-1 ]]
   then
      let i_occurrence=${i_occurrence}+1
      fun_block_grep ${i_line_number}

      echo ""
      echo "--------------------------------------------------------------------------------"
      echo ""
   fi

   i_line_number_before=${i_line_number}
done

export s_number_of_lines=$(grep ${si_search_string} ${si_file} | wc -l)

echo "================================================================================"
echo "---> Found ${i_occurrence} occurrences of <${si_search_string}>"
echo "================================================================================"

exit