# Flat profiler
#
# Copyright (C) 2016  Patrick "P. J." McDermott
#
# This file is part of the Eggshell Profiler.
#
# The Eggshell Profiler is free software: you can redistribute it
# and/or modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation, either version 3 of
# the License, or (at your option) any later version.
#
# The Eggshell Profiler is distributed in the hope that it will be
# useful, but WITHOUT ANY WARRANTY; without even the implied warranty
# of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with the Eggshell Profiler.  If not, see
# <http://www.gnu.org/licenses/>.

sp=
fn_name=
fn_start_time=
fn_end_time=
fns=
total_runtime=

sp_inc()
{
	sp=$((${sp} + 1))
}

sp_dec()
{
	sp=$((${sp} - 1))
}

frame_set()
{
	local p="${1}"
	shift 1

	eval "frame_${p}_name=\${fn_name}"
	eval "frame_${p}_time=0"
}

frame_get()
{
	local p="${1}"
	shift 1

	eval "fn_name=\${frame_${p}_name}"
	eval "fn_time=\${frame_${p}_time}"
}

frame_unset()
{
	local p="${1}"
	shift 1

	unset "frame_${p}_name"
	unset "frame_${p}_time"
}

frame_inc_time()
{
	local p="${1}"
	local value="${2}"

	eval "frame_${p}_time=\$((\${frame_${p}_time} + \${value}))"
}

frame_dec_time()
{
	local p="${1}"
	local value="${2}"

	eval "frame_${p}_time=\$((\${frame_${p}_time} - \${value}))"
}

ctxsw()
{
	local prev_sp="${1}"
	local next_sp="${2}"
	local time="${3}"
	shift 2

	frame_inc_time ${prev_sp} ${time}
	frame_dec_time ${next_sp} ${time}
}

record()
{
	local name="${1}"
	local time="${2}"
	shift 2

	case " ${fns} " in
		*" ${name} "*)
			eval "fn_timing_${name}=\$((\${fn_timing_${name}} + \
				\${time}))"
			eval "fn_calls_${name}=\$((\${fn_calls_${name}} + 1))"
			;;
		*)
			eval "fn_timing_${name}=\${time}"
			eval "fn_calls_${name}=1"
			fns="${fns} ${name}"
			;;
	esac
	total_runtime=$((${total_runtime} + ${time}))
}

fn_begin()
{
	local name="${1}"
	local time="${2}"
	shift 2
	local old_sp=

	old_sp=${sp}
	sp_inc
	fn_name="${name}"
	frame_set ${sp}
	ctxsw ${old_sp} ${sp} ${time}
}

fn_end()
{
	local name="${1}"
	local time="${2}"
	shift 2
	local old_sp=

	old_sp=${sp}
	sp_dec
	ctxsw ${old_sp} ${sp} ${time}
	frame_get ${old_sp}
	record ${fn_name} ${fn_time}
	frame_unset ${old_sp}
}

read_profile()
{
	local profile="${1}"
	shift 1

	while read time change fn; do
		# Convert to int.
		time="${time%.*}${time#*.}"
		case "${change}" in
			'B')
				fn_begin "${fn}" "${time}"
				;;
			'E')
				fn_end "${fn}" "${time}"
				;;
		esac
	done <"${profile}"
}

show_table()
{
	local fn=
	local time=
	local percent=
	local calls=
	local time_per_call=

	printf '                  self                   self\n'
	printf '%% time         seconds     calls      ms/call  name\n'
	for fn in ${fns}; do
		eval "time=\${fn_timing_${fn}}"
		eval "calls=\${fn_calls_${fn}}"
		percent=$(printf 'scale = 2; 100 * %d / %d\n' \
			${time} ${total_runtime} | bc)
		time=$(printf 'scale = 9; %d / 1000000000\n' ${time} | bc)
		time_per_call=$(printf 'scale = 6; %s * 1000 / %s\n' \
			${time} ${calls} | bc)
		printf '%6.2f  ' ${percent}
		printf '%14.9f  ' ${time}
		printf '%8d  ' ${calls}
		printf '%11.6f  ' ${time_per_call}
		printf '%s\n' "${fn}"
	done | sort -nr -k 1,4
}

flat_profile()
{
	local profile="${1}"
	shift 1
	sp=0
	fn_name=''
	fn_time=0
	fns=''
	total_runtime=0

	read_profile "${profile}"
	show_table
}