Much improved code, various bug fixes (relative temp convertion).

Drop support for the toggling feature.
mountaineerbr · Dec 22, 2024 · c62496b · c62496b
1 parent 07c965f
commit c62496b
Showing 1 changed file with 91 additions and 122 deletions.
diff --git a/ctemp.sh b/ctemp.sh
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 # Convert amongst temperature units
-# v0.6  sep/2024  by mountaineerbr
+# v0.7  dec/2024  by mountaineerbr
 
 #defaults
 
@@ -10,9 +10,6 @@ SCALEDEF=2
 #script name
 SN="${0##*/}"
 
-#make sure locale is set correctly
-export LC_NUMERIC=C
-
 #help
 HELP="$SN - Convert amongst temperature units
 
@@ -27,11 +24,6 @@ SYNOPSIS
 	degrees Celsius. TEMP is a floating point number and can be a
 	simple arithmetic expression.
 
-	If no unit is given, toggling between Celsius and Fahrenheit
-	units will be activated for absolute temperature conversions.
-	Toggling creates a temporary file at /tmp or equivalent. Input
-	from stdin is supported.
-
 	Option -r deals with relative temperatures conversions; for
 	example, a change of 45 degrees Fahrenheit corresponds to a
 	change of 25 degrees Celsius. 
@@ -40,16 +32,7 @@ SYNOPSIS
 	Floating point results are rounded to scale and trailing zeroes
 	are trimmed.
 
-	Temperature unit conversions are nonlinear; for example, temper-
-	ature conversions between Fahrenheit and Celsius scales cannot
-	be done by simply multiplying by conversion factors. These equa-
-	tions can only be used to convert from one specific temperature
-	to another specific temperature; for example, you can show that
-	the specific temperature of 0.0 Celsius equals 32 Fahrenheit, or
-	that the specific temperature of 100 Celsius equals 212 Fahrenheit.
-	However, a temperature difference of 100 degrees in the Celsius
-	scale is the same as a temperature difference of 180 degrees in
-	the Fahrenheit scale.
+	Input from stdin is supported.
 
 
 FORMULAS
@@ -64,8 +47,8 @@ FORMULAS
 		 0K = -273.15 C
 
 	Equivalence of relative temperature differences.
-		45K =   25 C
-		25C =   45 K
+		45F =   25 C
+		25K =   45 F
 		25C =   25 K
 
 
@@ -79,7 +62,7 @@ SEE ALSO
 	
 	Multiplications should be before divisions to avoid losing
 	precision if scale is small:
-	https://www.linuxquestions.org/questions/ubuntu-63/shell-script-to-convert-celsius-to-fahrenheit-929261/
+	<https://www.linuxquestions.org/questions/ubuntu-63/shell-script-to-convert-celsius-to-fahrenheit-929261>
 
 
 WARRANTY
@@ -88,8 +71,6 @@ WARRANTY
 
 	Tested with GNU Bash 5.0.
 
-	If useful, please consider sending feedback!  =)
-
 
 USAGE EXAMPLES
 	$ $SN 10
@@ -107,126 +88,132 @@ OPTIONS
 	-r 	Convert relative temperatures."
 
 
-#don't convert
-isSameUnitf()
-{
-	local degsign
-	if [[ "${FROMT:-x}${HELPER+x}" = "$TOT" ]]
-	then 	[[ $TOT = [kK] ]] || degsign=º
-		printf '%s%s%s\n' "$*" "${HELPER-$'\t'$degsign}" "${HELPER-$TOT}"
-		return 2
-	fi
-	return 0
-}
-
-#calculator command
+#bc fun
 calcf()
 {
-	bc <<-!
-	/* Round argument 'x' to 'd' digits */
-	define round(x, d) {
-		auto r, s
-		if(0 > x) {
-			return -round(-x, d)
-		}
-		r = x + 0.5*10^-d
-		s = scale
-		scale = d
-		r = r*10/10
-		scale = s  
-		return r
-	};
-	/* Serge3leo - https://stackoverflow.com/questions/26861118/rounding-numbers-with-bc-in-bash
-	 * MetroEast - https://askubuntu.com/questions/179898/how-to-round-decimals-using-bc-in-bash
-	 */
-	/* Truncate trailing zeroes */
-	define trunc(x){auto os;os=scale;for(scale=0;scale<=os;scale++)if(x==x/1){x/=1;scale=os;return x}}
-	/* http://phodd.net/gnu-bc/bcfaq.html
-	 */
-	scale=$SCALE+1; trunc( round($* , $SCALE) )
-	!
+	bc <<!
+/* Round argument 'x' to 'd' digits */
+define round(x, d) {
+  auto r, s
+  if(0 > x) {
+    return -round(-x, d)
+  }
+  r = x + 0.5*10^-d
+  s = scale
+  scale = d
+  r = r*10/10
+  scale = s  
+  return r
+};
+
+/* Truncate trailing zeroes */
+define trunc(x){auto os;os=scale;for(scale=0;scale<=os;scale++)if(x==x/1){x/=1;scale=os;return x}}
+
+scale=${SCALE:-2}+1
+trunc( round(${*} , ${SCALE:-2}) )
+!
 }
+#Serge3leo - https://stackoverflow.com/questions/26861118
+#MetroEast - https://askubuntu.com/questions/179898
+#http://phodd.net/gnu-bc/bcfaq.html
 
 #convert amongst absolute temps
 absolutef()
 {
-	local tot degsign res
+	typeset tot degsign res
 	typeset -u tot
 
-	#from fahrenheit
-	if [[ "$FROMT" = f ]] || [[ -z "$FROMT" && "$*" != "$TOGGLET" ]]
-	then 	[[ -z "$FROMT" ]] && TOGGLET="$*"
+	case "${FROMT}" in
+	    #from fahrenheit
+	    f|'')  if [[ -n "${TOT}" && -z "${TOT%%f}" ]]
+		then 	tot=f res=$1
 		#to celsius
-		if [[ -z "${TOT/c}" ]]
+		elif [[ -z "${TOT%%c}" ]]
 		then 	tot=c res=$( calcf "( (${1}) - 32) * 5/9" )
 		#to kelvin
 		else 	tot=k res=$( calcf "( ( (${1}) - 32) * 5/9) + 273.15" )
-		fi
-	#from celsius
-	elif [[ "$FROMT" = c ]]  || [[ -z "$FROMT" && "$*" = "$TOGGLET" ]]
-	then 	[[ -z "$FROMT" ]] && TOGGLET=
+		fi;;
+	    #from celsius
+	    c)  if [[ -n "${TOT}" && -z "${TOT%%c}" ]]
+		then 	tot=c res=$1
 		#to fahrenheit
-		if [[ -z "${TOT/f}" ]]
+		elif [[ -z "${TOT%%f}" ]]
 		then 	tot=f res=$( calcf "( (${1}) * 9/5) + 32" )
 		#to kelvin
 		else 	tot=k res=$( calcf "(${1}) + 273.15/1" )
-		fi
-	#from kelvin
-	else 	if [[ -z "${TOT/c}" ]]
+		fi;;
+	    #from kelvin
+	    k|*)  if [[ -n "${TOT}" && -z "${TOT%%k}" ]]
+		then 	tot=k res=$1
+		#to celsius
+		elif [[ -z "${TOT%%c}" ]]
 		then 	tot=c res=$( calcf "(${1}) - 273.15/1" )
 		#to fahrenheit
 		else 	tot=f res=$( calcf "( ( (${1}) - 273.15) * 9/5) + 32" )
-		fi
-	fi
+		fi;;
+	esac
 
 	[[ $tot = [kK] ]] || degsign=º
-	printf '%s%s%s\n' "$res" "${HELPER-$'\t'$degsign}" "${HELPER-$tot}"
+	((QUIET)) && printf '%s\n' "$res" ||
+	printf '%s %s%s\n' "$res" "$degsign" "$tot"
 }
 
 #convert amongst relative temps
 relativef()
 {
-	local degsign kzero kvar kdelta tzero tvar tdelta
-
-	#from farenheit or kelvin
-	if [[ "$FROMT$TOT" = [fk] ]] || [[ -z "$FROMT" && "$*" != "$TOGGLET" ]]
-	then 	[[ -z "$FROMT" ]] && FROMT=f TOGGLET="$*" 
-		TOT=c
-	#from celsius
-	elif [[ "$FROMT$TOT" = c ]] || [[ -z "$FROMT" && "$*" = "$TOGGLET" ]]
-	then 	[[ -z "$FROMT" ]] && FROMT=c TOGGLET=
-		TOT=f
-	fi
+	typeset degsign kzero kvar kdelta tzero tvar tdelta
+
+	case "${FROMT}${TOT}" in
+	  #from farenheit or null
+	  f|'')  [[ -z "$FROMT" ]] && FROMT=f
+		TOT=c;;
+	  #from celsius or kelvin
+	  c|k|*) [[ -z "$FROMT" ]] && FROMT=c
+		TOT=f;;
+	esac
 
 	#normalise temp unit for comparison in kelvin
-	kzero=$( HELPER= TOGGLET= TOT=k absolutef 0)
-	kvar=$(  HELPER= TOGGLET= TOT=k absolutef "$1")
+	kzero=$(QUIET=1 TOT=k absolutef 0)
+	kvar=$(QUIET=1 TOT=k absolutef "$1")
 	kdelta=$(calcf "$kvar - ( $kzero )" )
 
 	#transform kelvin delta in target temp delta
-	tzero=$( HELPER= TOGGLET= FROMT=k absolutef 0 )
-	tvar=$(  HELPER= TOGGLET= FROMT=k absolutef "$kdelta" )
+	tzero=$(QUIET=1 FROMT=k absolutef 0 )
+	tvar=$(QUIET=1 FROMT=k absolutef "$kdelta" )
 	tdelta=$(calcf "$tvar - ( $tzero )" )
 
 	[[ $TOT = [kK] ]] || degsign=º
-	printf '%s%s%s\n' "$tdelta" "${HELPER-$'\t'$degsign}" "${HELPER-$TOT}"
+	((QUIET)) && printf '%s\n' "$tdelta" ||
+	printf '%s %s%s\n' "$tdelta" "$degsign" "$TOT"
 }
+#  Temperature unit conversions are nonlinear; for example, temper-
+#  ature conversions between Fahrenheit and Celsius scales cannot
+#  be done by simply multiplying by conversion factors. These equa-
+#  tions can only be used to convert from one specific temperature
+#  to another specific temperature; for example, you can show that
+#  the specific temperature of 0.0 Celsius equals 32 Fahrenheit, or
+#  that the specific temperature of 100 Celsius equals 212 Fahrenheit.
+#  However, a temperature difference of 100 degrees in the Celsius
+#  scale is the same as a temperature difference of 180 degrees in
+#  the Fahrenheit scale.
+
+
+#prepare environment
+export LC_NUMERIC=C
 
-
-unset HELPER
 #parse opts
-while getopts 1234567890hHrRq c
+while getopts 1234567890hHrRqv c
 do 	case $c in
 		[0-9])  #scale
-			SCALE="${c%%[.,]*}"
+			SCALE="${SCALE}${c%%[.,]*}"
 			;;
 		[hH])
 			#help
 			echo "$HELP"
 			exit 
 			;;
-		[qQ]) 	#quiet
-			HELPER=
+		[qv]) 	#quiet
+			QUIET=1
 			;;
 		[rR]) #relative temps
 			OPTR=relative
@@ -246,17 +233,14 @@ elif [[ "$*" != *[0-9]* && ! -t 0 ]]
 then	set -- $(</dev/stdin) "$@"
 fi
 
-typeset -l UNITS
-UNITS="$*" UNITS="${UNITS//[^a-z]}" UNITS="${UNITS//celsius/c}"
+typeset -l UNITS; UNITS="$*";
+UNITS="${UNITS//[^a-z]}" UNITS="${UNITS//celsius/c}"
 UNITS="${UNITS//farenheit/f}" UNITS="${UNITS//kelvin/k}"
-if ILLEGAL='abdeg-jl-z' ;[[ "$UNITS" = *[$ILLEGAL]* ]]
-then 	printf '%s: err: illegal unit -- %s\n' "$SN" "${UNITS//[^${ILLEGAL}]}" >&2
+if [[ "$UNITS" = *[abdeg-jl-z]* ]]
+then 	printf '%s: err: illegal unit -- %s\n' "$SN" "${UNITS//[^abdeg-jl-z]}" >&2
 	exit 2
 fi
 
-set -- "${@//[^0-9,.-]}"  #remove units
-set -- "${@/,/.}"  #change comma to dot
-
 #from-unit is always the first
 (( ${#UNITS} )) && FROMT="${UNITS:0:1}"
 
@@ -265,26 +249,11 @@ set -- "${@/,/.}"  #change comma to dot
 
 [[ -n "$SCALE" ]] || SCALE="$SCALEDEF"
 
-#toggle
-TOGGLETTEMP="${TMPDIR:-/tmp}/$SN.$USER.togglet"
-[[ -z "$FROMT" && -e "$TOGGLETTEMP" ]] && read TOGGLET <"$TOGGLETTEMP"
+set -- "${@//[^0-9,.-]}"  #remove units
+set -- "${@/,/.}"  #change comma to dot
 
 #conversion type
-isSameUnitf "$*" || exit
 if [[ -n "$OPTR" ]]
 then 	relativef "$@"
 else 	absolutef "$@"
 fi
-code=$?
-
-#set toggle temp file?
-if [[ -n "$TOGGLET" ]]
-then 	if ! echo "$TOGGLET" >"$TOGGLETTEMP"
-	then 	printf '%s: err: cannot create tmp file -- %s\n' "$SN" "$TOGGLETTEMP" >&2
-		exit 1
-	fi
-elif [[ -e "$TOGGLETTEMP" ]]
-then 	rm -- "$TOGGLETTEMP" || exit
-fi
-
-exit ${code:-0}