# Hilfsfunktion zur Eingabe von Integers

# Wandelt eine Ziffernfolge in ein Integer >=0 um.
# DIGITS_to_I(MSBptr,len,base)
# > base: Stellenwertsystem-Basis, >=2, <=36
# > MSBptr/len/..: Ziffernfolge, bestehend aus Punkten (werden überlesen)
#     und Ziffern/Buchstaben mit Wert < base.
# < ergebnis: der dargestellte Integer >=0
# can trigger GC
  local object DIGITS_to_I (const chart* MSBptr, uintL len, uintD base);
  local object DIGITS_to_I(MSBptr,len,base)
    var const chart* MSBptr;
    var uintL len;
    var uintD base;
    { SAVE_NUM_STACK # num_stack retten
      var uintD* erg_MSDptr;
      var uintC erg_len;
      var uintD* erg_LSDptr;
      # Platz fürs Ergebnis:
      # 1+ceiling(len*log(base)/(intDsize*log(2))) oder etwas mehr Digits
      var uintL need = 1+floor(len,intDsize*256); # > len/(intDsize*256) >=0
      switch (base) # need mit ceiling(256*log(base)/log(2)) multiplizieren:
        { case 2: need = 256*need; break;
          case 3: need = 406*need; break;
          case 4: need = 512*need; break;
          case 5: need = 595*need; break;
          case 6: need = 662*need; break;
          case 7: need = 719*need; break;
          case 8: need = 768*need; break;
          case 9: need = 812*need; break;
          case 10: need = 851*need; break;
          case 11: need = 886*need; break;
          case 12: need = 918*need; break;
          case 13: need = 948*need; break;
          case 14: need = 975*need; break;
          case 15: need = 1001*need; break;
          case 16: need = 1024*need; break;
          case 17: need = 1047*need; break;
          case 18: need = 1068*need; break;
          case 19: need = 1088*need; break;
          case 20: need = 1107*need; break;
          case 21: need = 1125*need; break;
          case 22: need = 1142*need; break;
          case 23: need = 1159*need; break;
          case 24: need = 1174*need; break;
          case 25: need = 1189*need; break;
          case 26: need = 1204*need; break;
          case 27: need = 1218*need; break;
          case 28: need = 1231*need; break;
          case 29: need = 1244*need; break;
          case 30: need = 1257*need; break;
          case 31: need = 1269*need; break;
          case 32: need = 1280*need; break;
          case 33: need = 1292*need; break;
          case 34: need = 1303*need; break;
          case 35: need = 1314*need; break;
          case 36: need = 1324*need; break;
          default: NOTREACHED
        }
      # Nun gilt need >= len*log(base)/(intDsize*log(2)).
      need += 1;
      if ((intWCsize < 32) && (need > (uintL)(bitc(intWCsize)-1))) { BN_ueberlauf(); }
      num_stack_need(need,_EMA_,erg_LSDptr=);
      erg_MSDptr = erg_LSDptr; erg_len = 0;
      if (len > 0)
        { begin_arith_call();
          # Ziffern einzeln draufaddieren:
          dotimespL(len,len,
            { # erg_MSDptr/erg_len/erg_LSDptr ist eine NUDS, erg_len < need.
              var chart ch = *MSBptr++; # nächstes Character
              var cint c = as_cint(ch);
              if (!(c=='.')) # Punkt überlesen
                { # Wert von c ('0'-'9','A'-'Z','a'-'z') bilden:
                  c = c - '0';
                  if (c > '9'-'0') # keine Ziffer?
                    { c = c+'0'-'A'+10;
                      if (c > 'Z'-'A'+10) # kein Großbuchstabe?
                        { c = c+'A'-'a'; } # dann ein Kleinbuchstabe
                    }
                  # multipliziere erg mit base und addiere ch:
                 {var uintD carry = mulusmall_loop_down(base,erg_LSDptr,erg_len,c);
                  if (!(carry==0))
                    # muss NUDS vergrößern:
                    { *--erg_MSDptr = carry; erg_len++; }
            }   }});
          end_arith_call();
        }
     {var object result = NUDS_to_I(erg_MSDptr,erg_len);
      RESTORE_NUM_STACK # num_stack zurück
      return result;
    }}

