Nicolai Tufar wrote:
> Hello all,
>
> I would like to submit my changes to src/port/snprintf.c to
> enable %n$ format placeholder replacement in snprintf() and
> vsnprintf(). Additionally I implemented a trivial printf().
>
> I also attach a diff for configure.in to include snprintf.o
> in pgport but I am sure it is not the right thing to do.
> Could someone give a hint on where I need to place such a
> definition.
>
> Please review my patch. as Tom Lane pointed out there
> are 150 messages in the following files that do not print
> properly:
It took me a while to understand this but I get it now. This is the
best explanation I have seen, from Linux 2.6:
One can also specify explicitly which argument is taken, at each place
where an argument is required, by writing '%m$' instead of '%' and '*m$'
instead of '*', where the decimal integer m denotes the position in the
argument list of the desired argument, indexed starting from 1. Thus,
printf("%*d", width, num);
and
printf("%2$*1$d", width, num);
are equivalent. The second style allows repeated references to the
same argument. The C99 standard does not include the style using '$',
which comes from the Single Unix Specification. If the style using '$'
is used, it must be used throughout for all conversions taking an
argument and all width and precision arguments, but it may be mixed with
'%%' formats which do not consume an argument. There may be no gaps in
the numbers of arguments specified using '$'; for example, if
arguments 1 and 3 are specified, argument 2 must also be specified
somewhere in the format string.
I can see why this would be useful for translations because it uncouples
the order of the printf arguments from the printf string. However, I
have learned that Win32, HP-UX, NetBSD 2.0, and BSD/OS do not support
this. This is probably because it is not in C99 but in SUS (see above).
Anyway, this is too large to put into 8.0, but I am attaching a patch
for 8.1 that has the proper configure tests to check if the C library
supports this behavior. If it does not, the build will use our
port/snprintf.c.
One problem with that is that our snprintf.c is not thread-safe. Seems
the increases use of it will require us to fix this soon. I have added
to TODO:
* Make src/port/snprintf.c thread-safe
One change to the original port is that there was a define of a union
with no name:
+ union{
+ void* value;
+ long_long numvalue;
+ double fvalue;
+ int charvalue;
+ };
As far as I know a union with no name is illegal. I just removed the
"union {" and the closing brace.
--
Bruce Momjian | http://candle.pha.pa.us
pgman@candle.pha.pa.us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073
Index: configure
===================================================================
RCS file: /cvsroot/pgsql/configure,v
retrieving revision 1.425
diff -c -c -r1.425 configure
*** configure 18 Jan 2005 05:23:35 -0000 1.425
--- configure 13 Feb 2005 23:50:46 -0000
***************
*** 12162,12167 ****
--- 12162,12224 ----
done
+ echo "$as_me:$LINENO: checking printf supports argument control" >&5
+ echo $ECHO_N "checking printf supports argument control... $ECHO_C" >&6
+ if test "${pgac_cv_printf_arg_control+set}" = set; then
+ echo $ECHO_N "(cached) $ECHO_C" >&6
+ else
+ if test "$cross_compiling" = yes; then
+ pgac_cv_printf_arg_control=cross
+ else
+ cat >conftest.$ac_ext <<_ACEOF
+ #line $LINENO "configure"
+ #include "confdefs.h"
+ #include <stdio.h>
+
+ int does_printf_have_arg_control()
+ {
+ char buf[100];
+
+ /* can it swap arguments? */
+ snprintf(buf, 100, "%2$d|%1$d", 3, 4);
+ if (strcmp(buf, "4|3") != 0)
+ return 0;
+ return 1;
+ }
+ main() {
+ exit(! does_printf_have_arg_control());
+ }
+ _ACEOF
+ rm -f conftest$ac_exeext
+ if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
+ (eval $ac_link) 2>&5
+ ac_status=$?
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
+ { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); }; }; then
+ pgac_cv_printf_arg_control=yes
+ else
+ echo "$as_me: program exited with status $ac_status" >&5
+ echo "$as_me: failed program was:" >&5
+ cat conftest.$ac_ext >&5
+ ( exit $ac_status )
+ pgac_cv_printf_arg_control=no
+ fi
+ rm -f core core.* *.core conftest$ac_exeext conftest.$ac_objext
conftest.$ac_ext
+ fi
+
+ fi
+ echo "$as_me:$LINENO: result: $pgac_cv_printf_arg_control" >&5
+ echo "${ECHO_T}$pgac_cv_printf_arg_control" >&6
+
+ # cross compiler should use our snprintf too
+ if test $pgac_cv_printf_arg_control != yes ; then
+ pgac_need_repl_snprintf=yes
+ fi
# Check whether <stdio.h> declares snprintf() and vsnprintf(); if not,
# include/c.h will provide declarations. Note this is a separate test
Index: configure.in
===================================================================
RCS file: /cvsroot/pgsql/configure.in,v
retrieving revision 1.399
diff -c -c -r1.399 configure.in
*** configure.in 18 Jan 2005 05:23:36 -0000 1.399
--- configure.in 13 Feb 2005 23:50:47 -0000
***************
*** 881,886 ****
--- 881,891 ----
AC_CHECK_FUNCS(snprintf, [], pgac_need_repl_snprintf=yes)
AC_CHECK_FUNCS(vsnprintf, [], pgac_need_repl_snprintf=yes)
+ PGAC_FUNC_PRINTF_ARG_CONTROL
+ # cross compiler should use our snprintf too
+ if test $pgac_cv_printf_arg_control != yes ; then
+ pgac_need_repl_snprintf=yes
+ fi
# Check whether <stdio.h> declares snprintf() and vsnprintf(); if not,
# include/c.h will provide declarations. Note this is a separate test
***************
*** 1069,1074 ****
--- 1074,1081 ----
[AC_MSG_RESULT([cross-compiling])])
+ dnl 64-bit section
+ dnl
dnl Check to see if we have a working 64-bit integer type.
dnl This breaks down into two steps:
dnl (1) figure out if the compiler has a 64-bit int type with working
Index: config/c-library.m4
===================================================================
RCS file: /cvsroot/pgsql/config/c-library.m4,v
retrieving revision 1.29
diff -c -c -r1.29 c-library.m4
*** config/c-library.m4 16 Dec 2004 17:48:26 -0000 1.29
--- config/c-library.m4 13 Feb 2005 23:50:48 -0000
***************
*** 266,268 ****
--- 266,301 ----
LONG_LONG_INT_FORMAT=$pgac_cv_snprintf_long_long_int_format;;
*) AC_MSG_RESULT(none);;
esac])# PGAC_FUNC_SNPRINTF_LONG_LONG_INT_FORMAT
+
+
+ # PGAC_FUNC_PRINTF_ARG_CONTROL
+ # ---------------------------------------
+ # Determine if printf supports %1$ argument selection, e.g. %5$ selects
+ # the fifth argument after the printf print string.
+ # This is not in the C99 standard, but in the Single Unix Specification (SUS).
+ # It is used in our langauge translation strings.
+ #
+ AC_DEFUN([PGAC_FUNC_PRINTF_ARG_CONTROL],
+ [AC_MSG_CHECKING([printf supports argument control])
+ AC_CACHE_VAL(pgac_cv_printf_arg_control,
+ [AC_TRY_RUN([#include <stdio.h>
+
+ int does_printf_have_arg_control()
+ {
+ char buf[100];
+
+ /* can it swap arguments? */
+ snprintf(buf, 100, "%2$d|%1$d", 3, 4);
+ if (strcmp(buf, "4|3") != 0)
+ return 0;
+ return 1;
+ }
+ main() {
+ exit(! does_printf_have_arg_control());
+ }],
+ [pgac_cv_printf_arg_control=yes],
+ [pgac_cv_printf_arg_control=no],
+ [pgac_cv_printf_arg_control=cross])
+ ])dnl AC_CACHE_VAL
+ AC_MSG_RESULT([$pgac_cv_printf_arg_control])
+ ])# PGAC_FUNC_PRINTF_ARG_CONTROL
Index: src/port/snprintf.c
===================================================================
RCS file: /cvsroot/pgsql/src/port/snprintf.c,v
retrieving revision 1.4
diff -c -c -r1.4 snprintf.c
*** src/port/snprintf.c 29 Aug 2004 05:07:02 -0000 1.4
--- src/port/snprintf.c 13 Feb 2005 23:50:56 -0000
***************
*** 57,62 ****
--- 57,66 ----
typedef unsigned long ulong_long;
#endif
+ #ifndef NL_ARGMAX
+ #define NL_ARGMAX 4096
+ #endif
+
/*
** SNPRINTF, VSNPRINT -- counted versions of printf
**
***************
*** 85,93 ****
--- 89,115 ----
int snprintf(char *str, size_t count, const char *fmt,...);
int vsnprintf(char *str, size_t count, const char *fmt,
va_list args);
+ int printf(const char *format, ...);
static void dopr(char *buffer, const char *format, va_list args);
int
+ printf(const char *fmt,...)
+ {
+ int len;
+ va_list args;
+ static char* buffer[4096];
+ char* p;
+
+ va_start(args, fmt);
+ len = vsnprintf((char*)buffer, (size_t)4096, fmt, args);
+ va_end(args);
+ p = (char*)buffer;
+ for(;*p;p++)
+ putchar(*p);
+ return len;
+ }
+
+ int
snprintf(char *str, size_t count, const char *fmt,...)
{
int len;
***************
*** 124,129 ****
--- 146,155 ----
static char *output;
+ #define FMTSTR 1
+ #define FMTNUM 2
+ #define FMTFLOAT 3
+ #define FMTCHAR 4
static void
dopr(char *buffer, const char *format, va_list args)
***************
*** 139,145 ****
--- 165,198 ----
int ljust;
int len;
int zpad;
+ int i;
+ const char* format_save;
+ const char* fmtbegin;
+ int fmtpos = 1;
+ int realpos = 0;
+ int position;
+ static struct{
+ const char* fmtbegin;
+ const char* fmtend;
+ void* value;
+ long_long numvalue;
+ double fvalue;
+ int charvalue;
+ int ljust;
+ int len;
+ int zpad;
+ int maxwidth;
+ int base;
+ int dosign;
+ char type;
+ int precision;
+ int pointflag;
+ char func;
+ int realpos;
+ } fmtpar[NL_ARGMAX+1], *fmtparptr[NL_ARGMAX+1];
+
+ format_save = format;
output = buffer;
while ((ch = *format++))
{
***************
*** 148,161 ****
case '%':
ljust = len = zpad = maxwidth = 0;
longflag = longlongflag = pointflag = 0;
nextch:
ch = *format++;
switch (ch)
{
case 0:
! dostr("**end of format**", 0);
! *output = '\0';
! return;
case '-':
ljust = 1;
goto nextch;
--- 201,215 ----
case '%':
ljust = len = zpad = maxwidth = 0;
longflag = longlongflag = pointflag = 0;
+ fmtbegin = format - 1;
+ realpos = 0;
+ position = 0;
nextch:
ch = *format++;
switch (ch)
{
case 0:
! goto performpr;
case '-':
ljust = 1;
goto nextch;
***************
*** 174,180 ****
--- 228,241 ----
if (pointflag)
maxwidth = maxwidth *
10 + ch - '0';
else
+ {
len = len * 10 + ch -
'0';
+ position = position *
10 + ch - '0';
+ }
+ goto nextch;
+ case '$':
+ realpos = position;
+ len = 0;
goto nextch;
case '*':
if (pointflag)
***************
*** 203,209 ****
}
else
value = va_arg(args,
unsigned int);
! fmtnum(value, 10, 0, ljust,
len, zpad);
break;
case 'o':
case 'O':
--- 264,280 ----
}
else
value = va_arg(args,
unsigned int);
! fmtpar[fmtpos].fmtbegin =
fmtbegin;
! fmtpar[fmtpos].fmtend = format;
! fmtpar[fmtpos].numvalue = value;
! fmtpar[fmtpos].base = 10;
! fmtpar[fmtpos].dosign = 0;
! fmtpar[fmtpos].ljust = ljust;
! fmtpar[fmtpos].len = len;
! fmtpar[fmtpos].zpad = zpad;
! fmtpar[fmtpos].func = FMTNUM;
! fmtpar[fmtpos].realpos =
realpos?realpos:fmtpos;
! fmtpos++;
break;
case 'o':
case 'O':
***************
*** 217,223 ****
}
else
value = va_arg(args,
unsigned int);
! fmtnum(value, 8, 0, ljust, len,
zpad);
break;
case 'd':
case 'D':
--- 288,304 ----
}
else
value = va_arg(args,
unsigned int);
! fmtpar[fmtpos].fmtbegin =
fmtbegin;
! fmtpar[fmtpos].fmtend = format;
! fmtpar[fmtpos].numvalue = value;
! fmtpar[fmtpos].base = 8;
! fmtpar[fmtpos].dosign = 0;
! fmtpar[fmtpos].ljust = ljust;
! fmtpar[fmtpos].len = len;
! fmtpar[fmtpos].zpad = zpad;
! fmtpar[fmtpos].func = FMTNUM;
! fmtpar[fmtpos].realpos =
realpos?realpos:fmtpos;
! fmtpos++;
break;
case 'd':
case 'D':
***************
*** 230,236 ****
}
else
value = va_arg(args,
int);
! fmtnum(value, 10, 1, ljust,
len, zpad);
break;
case 'x':
if (longflag)
--- 311,327 ----
}
else
value = va_arg(args,
int);
! fmtpar[fmtpos].fmtbegin =
fmtbegin;
! fmtpar[fmtpos].fmtend = format;
! fmtpar[fmtpos].numvalue = value;
! fmtpar[fmtpos].base = 10;
! fmtpar[fmtpos].dosign = 1;
! fmtpar[fmtpos].ljust = ljust;
! fmtpar[fmtpos].len = len;
! fmtpar[fmtpos].zpad = zpad;
! fmtpar[fmtpos].func = FMTNUM;
! fmtpar[fmtpos].realpos =
realpos?realpos:fmtpos;
! fmtpos++;
break;
case 'x':
if (longflag)
***************
*** 242,248 ****
}
else
value = va_arg(args,
unsigned int);
! fmtnum(value, 16, 0, ljust,
len, zpad);
break;
case 'X':
if (longflag)
--- 333,349 ----
}
else
value = va_arg(args,
unsigned int);
! fmtpar[fmtpos].fmtbegin =
fmtbegin;
! fmtpar[fmtpos].fmtend = format;
! fmtpar[fmtpos].numvalue = value;
! fmtpar[fmtpos].base = 16;
! fmtpar[fmtpos].dosign = 0;
! fmtpar[fmtpos].ljust = ljust;
! fmtpar[fmtpos].len = len;
! fmtpar[fmtpos].zpad = zpad;
! fmtpar[fmtpos].func = FMTNUM;
! fmtpar[fmtpos].realpos =
realpos?realpos:fmtpos;
! fmtpos++;
break;
case 'X':
if (longflag)
***************
*** 254,260 ****
}
else
value = va_arg(args,
unsigned int);
! fmtnum(value, -16, 0, ljust,
len, zpad);
break;
case 's':
strvalue = va_arg(args, char *);
--- 355,371 ----
}
else
value = va_arg(args,
unsigned int);
! fmtpar[fmtpos].fmtbegin =
fmtbegin;
! fmtpar[fmtpos].fmtend = format;
! fmtpar[fmtpos].numvalue = value;
! fmtpar[fmtpos].base = -16;
! fmtpar[fmtpos].dosign = 1;
! fmtpar[fmtpos].ljust = ljust;
! fmtpar[fmtpos].len = len;
! fmtpar[fmtpos].zpad = zpad;
! fmtpar[fmtpos].func = FMTNUM;
! fmtpar[fmtpos].realpos =
realpos?realpos:fmtpos;
! fmtpos++;
break;
case 's':
strvalue = va_arg(args, char *);
***************
*** 262,273 ****
{
if (pointflag && len >
maxwidth)
len = maxwidth;
/* Adjust padding */
! fmtstr(strvalue, ljust,
len, zpad, maxwidth);
}
break;
case 'c':
ch = va_arg(args, int);
! dopr_outch(ch);
break;
case 'e':
case 'E':
--- 373,398 ----
{
if (pointflag && len >
maxwidth)
len = maxwidth;
/* Adjust padding */
! fmtpar[fmtpos].fmtbegin
= fmtbegin;
! fmtpar[fmtpos].fmtend =
format;
! fmtpar[fmtpos].value =
strvalue;
! fmtpar[fmtpos].ljust =
ljust;
! fmtpar[fmtpos].len =
len;
! fmtpar[fmtpos].zpad =
zpad;
! fmtpar[fmtpos].maxwidth
= maxwidth;
! fmtpar[fmtpos].func =
FMTSTR;
! fmtpar[fmtpos].realpos
= realpos?realpos:fmtpos;
! fmtpos++;
}
break;
case 'c':
ch = va_arg(args, int);
! fmtpar[fmtpos].fmtbegin =
fmtbegin;
! fmtpar[fmtpos].fmtend = format;
! fmtpar[fmtpos].charvalue = ch;
! fmtpar[fmtpos].func = FMTCHAR;
! fmtpar[fmtpos].realpos =
realpos?realpos:fmtpos;
! fmtpos++;
break;
case 'e':
case 'E':
***************
*** 275,285 ****
case 'g':
case 'G':
fvalue = va_arg(args, double);
! fmtfloat(fvalue, ch, ljust,
len, maxwidth, pointflag);
break;
case '%':
! dopr_outch(ch);
! continue;
default:
dostr("???????", 0);
}
--- 400,419 ----
case 'g':
case 'G':
fvalue = va_arg(args, double);
! fmtpar[fmtpos].fmtbegin =
fmtbegin;
! fmtpar[fmtpos].fmtend = format;
! fmtpar[fmtpos].fvalue = fvalue;
! fmtpar[fmtpos].type = ch;
! fmtpar[fmtpos].ljust = ljust;
! fmtpar[fmtpos].len = len;
! fmtpar[fmtpos].maxwidth =
maxwidth;
! fmtpar[fmtpos].pointflag =
pointflag;
! fmtpar[fmtpos].func = FMTFLOAT;
! fmtpar[fmtpos].realpos =
realpos?realpos:fmtpos;
! fmtpos++;
break;
case '%':
! break;
default:
dostr("???????", 0);
}
***************
*** 289,294 ****
--- 423,475 ----
break;
}
}
+ performpr:
+ /* shuffle pointers */
+ for(i = 1; i < fmtpos; i++)
+ {
+ fmtparptr[i] = &fmtpar[fmtpar[i].realpos];
+ }
+ output = buffer;
+ format = format_save;
+ while ((ch = *format++))
+ {
+ for(i = 1; i < fmtpos; i++)
+ {
+ if(ch == '%' && *format == '%')
+ {
+ format++;
+ continue;
+ }
+ if(fmtpar[i].fmtbegin == format - 1)
+ {
+ switch(fmtparptr[i]->func){
+ case FMTSTR:
+ fmtstr(fmtparptr[i]->value,
fmtparptr[i]->ljust,
+ fmtparptr[i]->len,
fmtparptr[i]->zpad,
+ fmtparptr[i]->maxwidth);
+ break;
+ case FMTNUM:
+ fmtnum(fmtparptr[i]->numvalue,
fmtparptr[i]->base,
+ fmtparptr[i]->dosign,
fmtparptr[i]->ljust,
+ fmtparptr[i]->len,
fmtparptr[i]->zpad);
+ break;
+ case FMTFLOAT:
+ fmtfloat(fmtparptr[i]->fvalue,
fmtparptr[i]->type,
+ fmtparptr[i]->ljust,
fmtparptr[i]->len,
+ fmtparptr[i]->precision,
fmtparptr[i]->pointflag);
+ break;
+ case FMTCHAR:
+ dopr_outch(fmtparptr[i]->charvalue);
+ break;
+ }
+ format = fmtpar[i].fmtend;
+ goto nochar;
+ }
+ }
+ dopr_outch(ch);
+ nochar:
+ /* nothing */
+ }
*output = '\0';
}
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