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Optimize f_substr() to use built-ins only

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Change f_snprintf() to use optimzed f_substr()
This commit is contained in:
Devin Teske 2016-01-31 21:28:41 +00:00
parent fcb16c1036
commit 0cb8bea7ed
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=295102
1 changed files with 57 additions and 32 deletions
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89
usr.sbin/bsdconfig/share/strings.subr
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@ -1,6 +1,6 @@
if [ ! "$_STRINGS_SUBR" ]; then _STRINGS_SUBR=1
#
# Copyright (c) 2006-2013 Devin Teske
# Copyright (c) 2006-2016 Devin Teske
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
@ -52,44 +52,53 @@ VALID_VARNAME_CHARS="0-9ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_"
############################################################ FUNCTIONS
# f_substr "$string" $start [$length]
# f_substr [-v $var_to_set] $string $start [$length]
#
# Simple wrapper to awk(1)'s `substr' function.
# Similar to awk(1)'s substr(), return length substring of string that begins
# at start position counted from 1.
#
f_substr()
{
local string="$1" start="${2:-0}" len="${3:-0}"
echo "$string" | awk "{ print substr(\$0, $start, $len) }"
}
local OPTIND=1 OPTARG __flag __var_to_set=
while getopts v: __flag; do
case "$__flag" in
v) __var_to_set="$OPTARG" ;;
esac
done
shift $(( $OPTIND - 1 ))
local __tmp="$1" __start="${2:-1}" __size="$3"
local __tbuf __tbuf_len __trim __trimq
# f_snprintf $var_to_set $size $format [$arguments ...]
#
# Similar to snprintf(3), write at most $size number of bytes into $var_to_set
# using printf(1) syntax (`$format [$arguments ...]'). The value of $var_to_set
# is NULL unless at-least one byte is stored from the output.
#
f_snprintf()
{
local __funcname=f_snprintf
local __var_to_set="$1" __size="$2"
shift 2 # var_to_set size
if [ "$__size" -eq 0 ] 2> /dev/null; then
setvar "$__var_to_set" ""
if [ ! "$__tmp" ]; then
[ "$__var_to_set" ] && setvar "$__var_to_set" ""
return ${SUCCESS:-0}
elif [ $? -ge 2 ] || [ $__size -lt 0 ]; then
setvar "$__var_to_set" ""
echo "$__funcname: invalid size argument \`__size'" >&2
fi
[ "$__start" -ge 1 ] 2> /dev/null || __start=1
if ! [ "${__size:-1}" -ge 1 ] 2> /dev/null; then
[ "$__var_to_set" ] && setvar "$__var_to_set" ""
return ${FAILURE:-1}
fi
local __f_snprintf_tmp
f_sprintf __f_snprintf_tmp "$@"
__trim=$(( $__start - 1 ))
while [ $__trim -gt 0 ]; do
__tbuf="?"
__tbuf_len=1
while [ $__tbuf_len -lt $(( $__trim / $__tbuf_len )) ]; do
__tbuf="$__tbuf?"
__tbuf_len=$(( $__tbuf_len + 1 ))
done
__trimq=$(( $__trim / $__tbuf_len ))
__trim=$(( $__trim - $__tbuf_len * $__trimq ))
while [ $__trimq -gt 0 ]; do
__tmp="${__tmp#$__tbuf}"
__trimq=$(( $__trimq - 1 ))
done
done
local __tmp_size=${#__f_snprintf_tmp}
local __trim=$(( $__tmp_size - $__size )) __trimq
local __tbuf __tbuf_len
local __tmp_size=${#__tmp}
local __mask __mask_len
__trim=$(( $__tmp_size - ${__size:-$__tmp_size} ))
while [ $__trim -gt 0 ]; do
__tbuf="?"
__tbuf_len=1
@ -102,11 +111,11 @@ f_snprintf()
__trimq=$(( $__trim / $__tbuf_len ))
__trim=$(( $__trim - $__tbuf_len * $__trimq ))
while [ $__trimq -gt 0 ]; do
__f_snprintf_tmp="${__f_snprintf_tmp%$__tbuf}"
__tmp="${__tmp%$__tbuf}"
__trimq=$(( $__trimq - 1 ))
done
else
__mask="$__f_snprintf_tmp"
__mask="$__tmp"
while [ $__tbuf_len -lt $(( $__size / $__tbuf_len )) ]
do
__tbuf="$__tbuf?"
@ -123,10 +132,26 @@ f_snprintf()
__mask="${__mask#$__tbuf}"
__trimq=$(( $__trimq - 1 ))
done
__f_snprintf_tmp="${__f_snprintf_tmp%"$__mask"}"
__tmp="${__tmp%"$__mask"}"
fi
done
setvar "$__var_to_set" "$__f_snprintf_tmp"
setvar "$__var_to_set" "$__tmp"
}
# f_snprintf $var_to_set $size $format [$arguments ...]
#
# Similar to snprintf(3), write at most $size number of bytes into $var_to_set
# using printf(1) syntax (`$format [$arguments ...]').
#
f_snprintf()
{
local __var_to_set="$1" __size="$2"
shift 2 # var_to_set size
local __f_snprintf_tmp
f_sprintf __f_snprintf_tmp "$@"
f_substr "$__var_to_set" "$__f_snprintf_tmp" 1 "$__size"
}
# f_sprintf $var_to_set $format [$arguments ...]