#!/usr/bin/awk -fBEGIN {	hextab ["0"] = 0; hextab ["8"] = 8;	hextab ["1"] = 1; hextab ["9"] = 9;	hextab ["2"] = 2; hextab ["A"] = hextab ["a"] = 10	hextab ["3"] = 3; hextab ["B"] = hextab ["b"] = 11;	hextab ["4"] = 4; hextab ["C"] = hextab ["c"] = 12;	hextab ["5"] = 5; hextab ["D"] = hextab ["d"] = 13;	hextab ["6"] = 6; hextab ["E"] = hextab ["e"] = 14;	hextab ["7"] = 7; hextab ["F"] = hextab ["f"] = 15;}{	decoded = ""	i   = 1	len = length ($0)	while ( i <= len ) {		c = substr ($0, i, 1)		if ( c == "%" ) {			if ( i+2 <= len ) {				c1 = substr ($0, i+1, 1)				c2 = substr ($0, i+2, 1)				if ( hextab [c1] == "" || hextab [c2] == "" ) {					print "WARNING: invalid hex encoding: %" c1 c2 | "cat >&2"				} else {					code = 0 + hextab [c1] * 16 + hextab [c2] + 0					c = sprintf ("%c", code)					i = i + 2				}			} else {				print "WARNING: invalid % encoding: " substr ($0, i, len - i)			}		} else if ( c == "+" ) {			c = " "		}		decoded = decoded c		++i	}	print decoded}