For-loop from C to Delphi

[WojTec]

Could you help translate this:

Code:

   for (i = 0; i < temp_length; i += 2)
   {
      if(temp[i] == 'X') {
         strcpy(symbol->errtxt, "Invalid position of X in Telepen data");
         return ZERROR_INVALID_DATA;
      }
      
      if(temp[i + 1] == 'X') {
         glyph = ctoi(temp[i]) + 17;
         count += glyph;
      } else {
         glyph = (10 * ctoi(temp[i])) + ctoi(temp[i + 1]);
         glyph += 27;
         count += glyph;
      }
   }

to something that can be understable for me (Delphi). I tried (but I know is bad):

Delphi-Quellcode:

  for I := 1 to Length(Data) do
  begin
    if Ord(Data[I + 1]) = 88 then
      Count := Count + StrToInt(Data[I]) + 17
    else
      Count := Count + (10 * StrToInt(Data[i])) + StrToInt(Data[i + 1]) + 17
    ;
  end;

:?:

[mkinzler]

The Index starts with 0

Delphi-Quellcode:

for I := 0 to Length(Data)-1 do

or

Delphi-Quellcode:

for I := Low(data) to High(Data) do

[Union]

This is not directly possible using a Delphi for, since OP doesn't support increments or decrements other than 1. Either use while / repeat construct or calculate the for range as well as all values derived from the counter.

[DeddyH]

Since we cannot know the type of Data, here are 2 suggestions:

Delphi-Quellcode:

//If Data is a string:
i := 1;
while i < Length(Data) do

//If Data is a dynamic array of Char:
i := 0;
while i < High(Data) do

//Anyway, I hope this is right in both cases:
  begin
    if Data[i] = 'X' then
      raise Exception.Create('Invalid position of X in Telepen data');
    if Data[i + 1] = 'X' then
      Count := Count + Ord(Data[i]) + 17
    else
      Count := Count + 27 + (Ord(Data[i]) * 10) + Ord(Data[i + 1]);
    inc(i, 2);
  end;

[WojTec]

Oh, I forgot: this code working on string.

I'm not sure valid is Ord() or StrToInt().
In C++ "char" is Byte in Delphi, but value contain ASCII or what?

Also I dont understand this statement:

Code:

if(temp[i] == 'X') {

In Delphi it mean 'X' or #88? What sense is this if-statement?

BTW: This is fragment from telepen.c from Zint project.

[DeddyH]

I am not very familiar with C, but I think ctoi means "character to integer", which is Ord() in Delphi. There is also a function called atoi which means "ASCII to integer" (Delphi: StringToInt). Both return different results. In my opinion Ord() is the right function for your purpose.

[WojTec]

Thare are these functions:

Code:

int ctoi(char source)
{ /* Converts a character 0-9 to its equivalent integer value */
   if((source >= '0') && (source <= '9'))
      return (source - '0');
   return(source - 'A' + 10);
}

char itoc(int source)
{ /* Converts an integer value to its hexadecimal character */
   if ((source >= 0) && (source <= 9)) {
      return ('0' + source); }
   else {
      return ('A' + (source - 10)); }
}

StrToInt working. But I'm still confused, what difference between ctoi() and atoi() if char in C is byte? You told C.atoi() = Delphi.StrToInt(), the same doing ctoi()?

Code:

s = "C++";
i = atoi(s[0]);
i = ctoi(s[0]);
i = s[0];

What values are assigned to i in these cases?

Delphi-Quellcode:

s = 'C++';
i = Ord(s[0]);
i = StrToInt(s[0]);
i = Ord(s[0]);

?

[Union]

Delphi-Quellcode:

StrCopy(s, 'C++');
i := Ord(s[0]); -> 67
i := StrToInt(s[0]); -> Invalid since 'C' is no number

[Medium]

More importantly: When working with Delphi Strings, keep in mind that their index starts with 1! If you have an array of char, the first index is zero though.

[DeddyH]

As shown in #4 ;)

[Medium]

Easy to forget, since Union seemed to use a zero base on Strings, which can lead to quite some confusion - I know that first hand, since I regularly forget it myself. But you're right of course :)

[Union]

Yes this was for PChar (see StrCopy). But the principle was to show the StrToInt() and Ord() function's results.

[DeddyH]

I tried to translate the two posted functions:

Delphi-Quellcode:

function ctoi(source: char): integer;
begin
  if (source >= '0') and (source <= '9') then
    Result := Ord(source) - Ord('0')
  else
    Result := Ord(source) - Ord('A') + 10;
end;

function itoc(source: integer): char;
begin
  if (source >= 0) and (source <= 9) then
    Result := Chr(Ord('0') + source)
  else
    Result := Chr(Ord('A') + source - 10);
end;

Untested, use at your own risk.

[Union]

Oder kürzer Or shorter:

Delphi-Quellcode:

function ctoi(source: char): integer;
begin
   result := StrToInt('$'+source);
end;

function itoc(source: integer): char;
begin
   c := Format('%x', [source])[1];
end;

[DeddyH]

And what about ctoi('Z')?

[Union]

Ok, my solution works only for hex :(