Re: [ft-devel] Error Description Strings

[Werner LEMBERG]

> However, I am not sure if I completely understand the other thing:
> do you prefer the solution by `N. Yoda' on StackOverflow (1) or the
> solution presented in `fterrors.h' (2)? (the latter uses the array,
> the former uses a switch/case)

I don't care.  What I dislike is that the #... lines are *within* the
structure or array.  There is no reason for it IMHO.

> 1. Switch/case is somewhat slower than array accesses but, IMO, the
> code is better to read (although I would exchange the lines with
> `FT_ERROR_START_LIST' and `FT_ERRORDEF' for improved readability)
> and it results in less code in total.  Also no global variables.
>
> 2. Faster execution but IMO results in somewhat messier code.  Also
> global variables.

Well, in (2) you can easily avoid a global variable if you use a
`static' read-only array local a function, e.g.,

  const char*
  FT_Error_String( FT_Error  error_code )
  {

#undef FTERRORS_H_
#define FT_ERRORDEF( e, v, s )  { e, s },
#define FT_ERROR_START_LIST     {
#define FT_ERROR_END_LIST       { 0, NULL } };

    static const struct
    {
      int          err_code;
      const char*  err_msg;
    } ft_errors[] =

#include FT_ERRORS_H


    ...
  }

> Efficiency is generally nice, however somewhat neglectable when it
> comes to debugging and really, it shouldn't be THAT much of a
> difference.  Beauty lies in the eye of the beholder and I'll
> willingly agree to whatever you prefer.

I think it really doesn't matter.  Using a switch statement is
probably less coding.

>> I can imagine to activate that automatically if tracing is active,
>> doing a call within the `FT_THROW' macro.
>
> Totally, why not :) However, for my (fuzzing) purposes, I'd
> appreciate it if `FT_Get_Error_Message' was independent of tracing
> since I usually don't use FreeType's tracing but do log all return
> values (esp. `if ( error != 0 ) ...').

Hmm.  Then maybe

  #define FT_CONFIG_OPTION_ERROR_STRINGS

if people want `FT_Error_String', and

  #define FT_DEBUG_LEVEL_THROW

to make `FT_Error_String' be called in `FT_THROW'.


    Werner