Re: Simplify formatting.c - Mailing list pgsql-patches

Bruce Momjian wrote:
> Bruce Momjian wrote:
> > Alvaro Herrera wrote:
> > > Bruce Momjian wrote:
> > >
> > > > I moved str_initcap() over into oracle_compat.c and then had initcap()
> > > > convert to/from TEXT to call it.  The code is a little weird because
> > > > str_initcap() needs to convert to text to use texttowcs(), so in
> > > > multibyte encodings initcap converts the string to text, then to char,
> > > > then to text to call texttowcs().  I didn't see a cleaner way to do
> > > > this.
> > >
> > > Why not use wchar2char?  It seems there's room for extra cleanup here.
> > >
> > > Also, the prototype of str_initcap in builtins.h looks out of place.
> >
> > I talked to Alvaro on IM, and there is certainly much more cleanup to do
> > in this area. I will work from the bottom up.  First, is moving the
> > USE_WIDE_UPPER_LOWER define to c.h, and removing TS_USE_WIDE and using
> > USE_WIDE_UPPER_LOWER instead.  Patch attached and applied.
>
> The second step is to move wchar2char() and char2wchar() from tsearch
> into /mb to be easier to use for other modules;  also move pnstrdup().

The third step is for oracle_compat.c::initcap() to use
formatting.c::str_initcap().  You can see the result;  patch attached
(not applied).

This greatly reduces the size of initcap(), with the downside that we
are making two extra copies of the string to convert it to/from char*.

Is this acceptable?  If it is I will do the same for uppper()/lower()
with similar code size reduction and modularity.

If not perhaps I should keep the non-multibyte code in initcap() and
have only the multi-byte use str_initcap().

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: src/backend/utils/adt/formatting.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/formatting.c,v
retrieving revision 1.142
diff -c -c -r1.142 formatting.c
*** src/backend/utils/adt/formatting.c    17 Jun 2008 16:09:06 -0000    1.142
--- src/backend/utils/adt/formatting.c    21 Jun 2008 20:00:45 -0000
***************
*** 1499,1526 ****
      if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c())
      {
          wchar_t        *workspace;
!         text        *in_text;
!         text        *out_text;
!         int            i;

!         in_text = cstring_to_text(buff);
!         workspace = texttowcs(in_text);

!         for (i = 0; workspace[i] != 0; i++)
          {
              if (wasalnum)
!                 workspace[i] = towlower(workspace[i]);
              else
!                 workspace[i] = towupper(workspace[i]);
!             wasalnum = iswalnum(workspace[i]);
          }

!         out_text = wcstotext(workspace, i);
!         result = text_to_cstring(out_text);

          pfree(workspace);
-         pfree(in_text);
-         pfree(out_text);
      }
      else
  #endif        /* USE_WIDE_UPPER_LOWER */
--- 1499,1525 ----
      if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c())
      {
          wchar_t        *workspace;
!         int            curr_char = 0;

!         /* Output workspace cannot have more codes than input bytes */
!         workspace = (wchar_t *) palloc((strlen(buff) + 1) * sizeof(wchar_t));

!         char2wchar(workspace, strlen(buff) + 1, buff, strlen(buff) + 1);
!
!         for (curr_char = 0; workspace[curr_char] != 0; curr_char++)
          {
              if (wasalnum)
!                 workspace[curr_char] = towlower(workspace[curr_char]);
              else
!                 workspace[curr_char] = towupper(workspace[curr_char]);
!             wasalnum = iswalnum(workspace[curr_char]);
          }

!         /* Make result large enough; case change might change number of bytes */
!         result = palloc(curr_char * MB_CUR_MAX + 1);

+         wchar2char(result, workspace, curr_char * MB_CUR_MAX + 1);
          pfree(workspace);
      }
      else
  #endif        /* USE_WIDE_UPPER_LOWER */
Index: src/backend/utils/adt/oracle_compat.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/oracle_compat.c,v
retrieving revision 1.80
diff -c -c -r1.80 oracle_compat.c
*** src/backend/utils/adt/oracle_compat.c    17 Jun 2008 16:09:06 -0000    1.80
--- src/backend/utils/adt/oracle_compat.c    21 Jun 2008 20:00:45 -0000
***************
*** 467,530 ****
  Datum
  initcap(PG_FUNCTION_ARGS)
  {
! #ifdef USE_WIDE_UPPER_LOWER

!     /*
!      * Use wide char code only when max encoding length > 1 and ctype != C.
!      * Some operating systems fail with multi-byte encodings and a C locale.
!      * Also, for a C locale there is no need to process as multibyte.
!      */
!     if (pg_database_encoding_max_length() > 1 && !lc_ctype_is_c())
!     {
!         text       *string = PG_GETARG_TEXT_PP(0);
!         text       *result;
!         wchar_t    *workspace;
!         int            wasalnum = 0;
!         int            i;
!
!         workspace = texttowcs(string);
!
!         for (i = 0; workspace[i] != 0; i++)
!         {
!             if (wasalnum)
!                 workspace[i] = towlower(workspace[i]);
!             else
!                 workspace[i] = towupper(workspace[i]);
!             wasalnum = iswalnum(workspace[i]);
!         }
!
!         result = wcstotext(workspace, i);
!
!         pfree(workspace);
!
!         PG_RETURN_TEXT_P(result);
!     }
!     else
! #endif   /* USE_WIDE_UPPER_LOWER */
!     {
!         text       *string = PG_GETARG_TEXT_P_COPY(0);
!         int            wasalnum = 0;
!         char       *ptr;
!         int            m;
!
!         /*
!          * Since we copied the string, we can scribble directly on the value
!          */
!         ptr = VARDATA(string);
!         m = VARSIZE(string) - VARHDRSZ;

!         while (m-- > 0)
!         {
!             if (wasalnum)
!                 *ptr = tolower((unsigned char) *ptr);
!             else
!                 *ptr = toupper((unsigned char) *ptr);
!             wasalnum = isalnum((unsigned char) *ptr);
!             ptr++;
!         }
!
!         PG_RETURN_TEXT_P(string);
!     }
  }


--- 467,482 ----
  Datum
  initcap(PG_FUNCTION_ARGS)
  {
!     char    *in_string, *out_string;
!     text    *result;

!     in_string = text_to_cstring(PG_GETARG_TEXT_PP(0));
!     out_string = str_initcap(in_string);
!     pfree(in_string);
!     result = cstring_to_text(out_string);
!     pfree(out_string);

!     PG_RETURN_TEXT_P(result);
  }