#!/bin/bash

if [ "$#" -eq 0 ]
then
  echo "# Usage: drive_strength netlist instance drive"
  echo "#"
  echo "#   will change the drive strength of instance in netlist to value drive."
  echo "#   eg  drive_strength multi8 r_0_ins x2"
  echo "#   will change the drive strength of instance r_0_ins in multi8.vst to at least an x2."
  echo "#   If the drive strength is already an x2 or more, it won't be changed."
  exit 1
fi
if [ "$#" -eq 1 ]
then
  echo "# Usage: drive_strength netlist instance drive"
  echo "#"
  echo "#   Missing instance."
  echo "#   Please supply the instance name."
  exit 1
fi
if [ "$#" -eq 2 ]
then
  echo "# Usage: drive_strength netlist instance drive"
  echo "#"
  echo "#   Missing drive."
  echo "#   Please supply the required drive strength."
  exit 1
fi
if test -f $1.vst
then
  netlist=$1
else
  echo "# Usage: drive_strength netlist instance drive"
  echo "#"
  echo "#   The netlist supplied "$1".vst does not exist. Please check."
  exit 1
fi
inst=$2
inst_no=$(grep -c "^ *$inst *:" ${netlist}.vst)
if [ "$inst_no" -eq 0 ]
then
  echo "# Usage: drive_strength netlist instance drive"
  echo "#"
  echo "#   The instance name supplied  "$inst"  is not present in the netlist. Please check."
  exit 1
else
  cell=$(grep "^ *${inst} " ${netlist}.vst | \
    sed 's/^ *//' | \
    cut -f 3 -d ' ')
fi
drive=$3
if [ "${drive:1:1}" -eq 0 ]
then
  drivex10=${drive:2:1}
else
  drivex10=$(echo ${drive:1:1} | awk '{printf "%3d\n", $1*10 }')
fi

# Find existing drive strength

old_drive=${cell##*v?}
if [ "${old_drive:1:1}" -eq 0 ]
then
  old_drivex10=${old_drive:2:1}
else
  old_drivex10=$(echo ${old_drive:1:1} | awk '{printf "%3d\n", $1*10 }')
fi
if [ "$drivex10" -le "$old_drivex10" ]
then
  echo "# Instance "$inst", cell "$cell" already has a drive strength of "$old_drive"."
  echo "# Netlist "$netlist".vst has not been changed."
  exit 0
fi
cell2=$(echo $cell | sed "s/${old_drive}$/${drive}/")

# Change drive strength of instance to new value

sed -i "/^ *${inst} / s/^ *${inst}  *:  *\([^ ][^ ]*v[^ ][^ ]*\)x[^ ][^ ]* *$/${inst} : \1${drive}/" ${netlist}.vst
echo "# Instance "$inst", cell "$cell" has been buffered up to "$cell2"."

# Add new cell name to Component list if not already there

if [ "$(grep -c "^ *Component  *${cell2} *$" ${netlist}.vst)" -eq 0 ]
then
  sed -n "/^ *Component  *${cell} *$/,/^ *end / p" ${netlist}.vst > this_comp
  sed -i "1 s/${cell}/${cell2}/" this_comp
  let "comp_lines=$(wc -l this_comp | cut -f 1 -d ' ')-1"
  sed -i "1,${comp_lines} s/^.*$/&\\\/" this_comp
  sed -i "1 i\/^ *Component  *${cell}/ i" this_comp
  sed -i '1 s/$/\\/' this_comp
  sed -i -f this_comp ${netlist}.vst
fi