############################################################################
#
#	Name:	radcon.icn
#
#	Title:	Radix conversion
#
#	Author:	Ralph E. Griswold
#
#	Date:	June 10, 1988
#
############################################################################
#  
#  The following procedures convert numbers from one radix to
#  another. The letters from a to z are used for ``digits'' greater
#  than 9. All the conversion procedures fail if the conversion can-
#  not be made.
#  
#       exbase10(i,j)  convert base-10 integer i to base j
#  
#       inbase10(s,i)  convert base-i integer s to base 10
#  
#       radcon(s,i,j)  convert base-i integer s to base j
#  
#  Limitation:
#
#     The maximum base allowed is 36.
#  
############################################################################

procedure exbase10(i,j)
   static digits
   local s, d, sign
   initial digits := &digits || &lcase
   if i = 0 then return 0
   if i < 0 then {
      sign := "-"
      i := -i
      }
   else sign := ""
   s := ""
   while i > 0 do {
      d := i % j
      if d > 9 then d := digits[d + 1]
      s := d || s
      i /:= j
      }
   return sign || s
end

procedure inbase10(s,i)
   if s[1] == "-" then return "-" || integer(i || "r" || s[2:0])
   else return integer(i || "r" || s)
end

procedure radcon(s,i,j)
   return exbase10(inbase10(s,i),j)
end