Fix a rather sizable number of problems in our homegrown snprintf, such as
authorTom Lane <tgl@sss.pgh.pa.us>
Mon, 5 Dec 2005 02:39:38 +0000 (02:39 +0000)
committerTom Lane <tgl@sss.pgh.pa.us>
Mon, 5 Dec 2005 02:39:38 +0000 (02:39 +0000)
incorrect implementation of argument reordering, arbitrary limit of output
size for sprintf and fprintf, willingness to access more bytes than "%.Ns"
specification allows, wrong formatting of LONGLONG_MIN, various field-padding
bugs and omissions.  I believe it now accurately implements a subset of
the Single Unix Spec requirements (remaining unimplemented features are
documented, too).  Bruce Momjian and Tom Lane.

src/port/snprintf.c

index 910f40320a209948250ce7fab281a4870f9751a2..8f33971263adc5441f54b57c1494b12114e2889b 100644 (file)
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
+ *
+ * $PostgreSQL: pgsql/src/port/snprintf.c,v 1.30 2005/12/05 02:39:38 tgl Exp $
  */
 
 #include "c.h"
 
+#include <limits.h>
 #ifndef WIN32
 #include <sys/ioctl.h>
 #endif
 #include <sys/param.h>
 
+#ifndef NL_ARGMAX
+#define NL_ARGMAX 16
+#endif
+
 
 /*
-** SNPRINTF, VSNPRINT -- counted versions of printf
-**
-** These versions have been grabbed off the net.  They have been
-** cleaned up to compile properly and support for .precision and
-** %lx has been added.
-*/
+ * SNPRINTF, VSNPRINTF and friends
+ *
+ * These versions have been grabbed off the net.  They have been
+ * cleaned up to compile properly and support for most of the Single
+ * Unix Specification has been added.  Remaining unimplemented features
+ * are:
+ *
+ * 1. No locale support: the radix character is always '.' and the '
+ * (single quote) format flag is ignored.
+ *
+ * 2. No support for the "%n" format specification.
+ *
+ * 3. No support for wide characters ("lc" and "ls" formats).
+ *
+ * 4. No support for "long double" ("Lf" and related formats).
+ *
+ * 5. Space and '#' flags are not implemented.
+ */
 
 /**************************************************************
  * Original:
  * A bombproof version of doprnt (dopr) included.
  * Sigh.  This sort of thing is always nasty do deal with. Note that
  * the version here does not include floating point. (now it does ... tgl)
- *
- * snprintf() is used instead of sprintf() as it does limit checks
- * for string length.  This covers a nasty loophole.
- *
- * The other functions are there to prevent NULL pointers from
- * causing nasty effects.
  **************************************************************/
 
-/*static char _id[] = "$PostgreSQL: pgsql/src/port/snprintf.c,v 1.29 2005/10/15 02:49:51 momjian Exp $";*/
-
-static void dopr(char *buffer, const char *format, va_list args, char *end);
-
 /* Prevent recursion */
 #undef vsnprintf
 #undef snprintf
@@ -73,17 +82,66 @@ static void dopr(char *buffer, const char *format, va_list args, char *end);
 #undef fprintf
 #undef printf
 
+/* Info about where the formatted output is going */
+typedef struct
+{
+   char       *bufptr;         /* next buffer output position */
+   char       *bufstart;       /* first buffer element */
+   char       *bufend;         /* last buffer element, or NULL */
+   /* bufend == NULL is for sprintf, where we assume buf is big enough */
+   FILE       *stream;         /* eventual output destination, or NULL */
+   int         nchars;         /* # chars already sent to stream */
+} PrintfTarget;
+
+/*
+ * Info about the type and value of a formatting parameter.  Note that we
+ * don't currently support "long double", "wint_t", or "wchar_t *" data,
+ * nor the '%n' formatting code; else we'd need more types.  Also, at this
+ * level we need not worry about signed vs unsigned values.
+ */
+typedef enum
+{
+   ATYPE_NONE = 0,
+   ATYPE_INT,
+   ATYPE_LONG,
+   ATYPE_LONGLONG,
+   ATYPE_DOUBLE,
+   ATYPE_CHARPTR
+} PrintfArgType;
+
+typedef union
+{
+   int         i;
+   long        l;
+   int64       ll;
+   double      d;
+   char       *cptr;
+} PrintfArgValue;
+
+
+static void flushbuffer(PrintfTarget *target);
+static int dopr(PrintfTarget *target, const char *format, va_list args);
+
+
 int
 pg_vsnprintf(char *str, size_t count, const char *fmt, va_list args)
 {
-   char       *end;
-
-   str[0] = '\0';
-   end = str + count - 1;
-   dopr(str, fmt, args, end);
-   if (count > 0)
-       end[0] = '\0';
-   return strlen(str);
+   PrintfTarget    target;
+
+   if (str == NULL || count == 0)
+       return 0;
+   target.bufstart = target.bufptr = str;
+   target.bufend = str + count - 1;
+   target.stream = NULL;
+   /* target.nchars is unused in this case */
+   if (dopr(&target, fmt, args))
+   {
+       *(target.bufptr) = '\0';
+       errno = EINVAL;         /* bad format */
+       return -1;
+   }
+   *(target.bufptr) = '\0';
+   return target.bufptr - target.bufstart;
 }
 
 int
@@ -98,34 +156,73 @@ pg_snprintf(char *str, size_t count, const char *fmt,...)
    return len;
 }
 
+static int
+pg_vsprintf(char *str, const char *fmt, va_list args)
+{
+   PrintfTarget    target;
+
+   if (str == NULL)
+       return 0;
+   target.bufstart = target.bufptr = str;
+   target.bufend = NULL;
+   target.stream = NULL;
+   /* target.nchars is unused in this case */
+   if (dopr(&target, fmt, args))
+   {
+       *(target.bufptr) = '\0';
+       errno = EINVAL;         /* bad format */
+       return -1;
+   }
+   *(target.bufptr) = '\0';
+   return target.bufptr - target.bufstart;
+}
+
 int
 pg_sprintf(char *str, const char *fmt,...)
 {
    int         len;
    va_list     args;
-   char        buffer[4096];
 
    va_start(args, fmt);
-   len = pg_vsnprintf(buffer, (size_t) 4096, fmt, args);
+   len = pg_vsprintf(str, fmt, args);
    va_end(args);
-   /* limit output to string */
-   StrNCpy(str, buffer, (len + 1 < 4096) ? len + 1 : 4096);
    return len;
 }
 
+static int
+pg_vfprintf(FILE *stream, const char *fmt, va_list args)
+{
+   PrintfTarget    target;
+   char        buffer[1024];   /* size is arbitrary */
+
+   if (stream == NULL)
+   {
+       errno = EINVAL;
+       return -1;
+   }
+   target.bufstart = target.bufptr = buffer;
+   target.bufend = buffer + sizeof(buffer) - 1;
+   target.stream = stream;
+   target.nchars = 0;
+   if (dopr(&target, fmt, args))
+   {
+       errno = EINVAL;         /* bad format */
+       return -1;
+   }
+   /* dump any remaining buffer contents */
+   flushbuffer(&target);
+   return target.nchars;
+}
+
 int
 pg_fprintf(FILE *stream, const char *fmt,...)
 {
    int         len;
    va_list     args;
-   char        buffer[4096];
-   char       *p;
 
    va_start(args, fmt);
-   len = pg_vsnprintf(buffer, (size_t) 4096, fmt, args);
+   len = pg_vfprintf(stream, fmt, args);
    va_end(args);
-   for (p = buffer; *p; p++)
-       putc(*p, stream);
    return len;
 }
 
@@ -134,528 +231,655 @@ pg_printf(const char *fmt,...)
 {
    int         len;
    va_list     args;
-   char        buffer[4096];
-   char       *p;
 
    va_start(args, fmt);
-   len = pg_vsnprintf(buffer, (size_t) 4096, fmt, args);
+   len = pg_vfprintf(stdout, fmt, args);
    va_end(args);
-
-   for (p = buffer; *p; p++)
-       putchar(*p);
    return len;
 }
 
-static int adjust_sign(int is_negative, int forcesign, int *signvalue);
-static void adjust_padlen(int minlen, int vallen, int leftjust, int *padlen);
-static void leading_pad(int zpad, int *signvalue, int *padlen, char *end,
-           char **output);
-static void trailing_pad(int *padlen, char *end, char **output);
+/* call this only when stream is defined */
+static void
+flushbuffer(PrintfTarget *target)
+{
+   size_t  nc = target->bufptr - target->bufstart;
+
+   if (nc > 0)
+       target->nchars += fwrite(target->bufstart, 1, nc, target->stream);
+   target->bufptr = target->bufstart;
+}
+
 
 static void fmtstr(char *value, int leftjust, int minlen, int maxwidth,
-      char *end, char **output);
-static void fmtint(int64 value, int base, int dosign, int forcesign,
-      int leftjust, int minlen, int zpad, char *end, char **output);
+      int pointflag, PrintfTarget *target);
+static void fmtptr(void *value, PrintfTarget *target);
+static void fmtint(int64 value, char type, int forcesign,
+      int leftjust, int minlen, int zpad, int precision, int pointflag,
+      PrintfTarget *target);
+static void fmtchar(int value, int leftjust, int minlen, PrintfTarget *target);
 static void fmtfloat(double value, char type, int forcesign,
- int leftjust, int minlen, int zpad, int precision, int pointflag, char *end,
-        char **output);
-static void dostr(char *str, int cut, char *end, char **output);
-static void dopr_outch(int c, char *end, char **output);
-
-#define FMTSTR     1
-#define FMTNUM     2
-#define FMTNUM_U   3
-#define FMTFLOAT   4
-#define FMTCHAR        5
-#define FMTWIDTH   6
-#define FMTLEN     7
+       int leftjust, int minlen, int zpad, int precision, int pointflag,
+       PrintfTarget *target);
+static void dostr(const char *str, int slen, PrintfTarget *target);
+static void dopr_outch(int c, PrintfTarget *target);
+static int adjust_sign(int is_negative, int forcesign, int *signvalue);
+static void adjust_padlen(int minlen, int vallen, int leftjust, int *padlen);
+static void leading_pad(int zpad, int *signvalue, int *padlen,
+           PrintfTarget *target);
+static void trailing_pad(int *padlen, PrintfTarget *target);
+
 
 /*
  * dopr(): poor man's version of doprintf
  */
-
-static void
-dopr(char *buffer, const char *format, va_list args, char *end)
+static int
+dopr(PrintfTarget *target, const char *format, va_list args)
 {
+   const char *format_start = format;
    int         ch;
+   bool        have_dollar;
+   bool        have_non_dollar;
+   bool        have_star;
+   bool        afterstar;
+   int         accum;
    int         longlongflag;
    int         longflag;
    int         pointflag;
-   int         maxwidth;
    int         leftjust;
-   int         minlen;
+   int         fieldwidth;
+   int         precision;
    int         zpad;
    int         forcesign;
+   int         last_dollar;
+   int         fmtpos;
+   int         cvalue;
+   int64       numvalue;
+   double      fvalue;
+   char       *strvalue;
    int         i;
-   const char *format_save;
-   const char *fmtbegin;
-   int         fmtpos = 1;
-   int         realpos = 0;
-   int         precision;
-   int         position;
-   char       *output;
-   int         nargs = 1;
-   const char *p;
-   struct fmtpar
-   {
-       const char *fmtbegin;
-       const char *fmtend;
-       void       *value;
-       int64       numvalue;
-       double      fvalue;
-       int         charvalue;
-       int         leftjust;
-       int         minlen;
-       int         zpad;
-       int         maxwidth;
-       int         base;
-       int         dosign;
-       int         forcesign;
-       char        type;
-       int         precision;
-       int         pointflag;
-       char        func;
-       int         realpos;
-       int         longflag;
-       int         longlongflag;
-   }          *fmtpar, **fmtparptr;
+   PrintfArgType argtypes[NL_ARGMAX+1];
+   PrintfArgValue argvalues[NL_ARGMAX+1];
 
    /*
-    * Create enough structures to hold all arguments.  This overcounts, eg
-    * not all '*' characters are necessarily arguments, but it's not worth
-    * being exact.
+    * Parse the format string to determine whether there are %n$ format
+    * specs, and identify the types and order of the format parameters.
     */
-   for (p = format; *p != '\0'; p++)
-       if (*p == '%' || *p == '*')
-           nargs++;
+   have_dollar = have_non_dollar = false;
+   last_dollar = 0;
+   MemSet(argtypes, 0, sizeof(argtypes));
 
-   /* Need to use malloc() because memory system might not be started yet. */
-   if ((fmtpar = malloc(sizeof(struct fmtpar) * nargs)) == NULL)
+   while ((ch = *format++) != '\0')
    {
-       fprintf(stderr, _("out of memory\n"));
-       exit(1);
+       if (ch != '%')
+           continue;
+       longflag = longlongflag = pointflag = 0;
+       fmtpos = accum = 0;
+       afterstar = false;
+   nextch1:
+       ch = *format++;
+       if (ch == '\0')
+           break;              /* illegal, but we don't complain */
+       switch (ch)
+       {
+           case '-':
+           case '+':
+               goto nextch1;
+           case '0':
+           case '1':
+           case '2':
+           case '3':
+           case '4':
+           case '5':
+           case '6':
+           case '7':
+           case '8':
+           case '9':
+               accum = accum * 10 + (ch - '0');
+               goto nextch1;
+           case '.':
+               pointflag = 1;
+               accum = 0;
+               goto nextch1;
+           case '*':
+               if (afterstar)
+                   have_non_dollar = true; /* multiple stars */
+               afterstar = true;
+               accum = 0;
+               goto nextch1;
+           case '$':
+               have_dollar = true;
+               if (accum <= 0 || accum > NL_ARGMAX)
+                   return -1;
+               if (afterstar)
+               {
+                   if (argtypes[accum] &&
+                       argtypes[accum] != ATYPE_INT)
+                       return -1;
+                   argtypes[accum] = ATYPE_INT;
+                   last_dollar = Max(last_dollar, accum);
+                   afterstar = false;
+               }
+               else
+                   fmtpos = accum;
+               accum = 0;
+               goto nextch1;
+           case 'l':
+               if (longflag)
+                   longlongflag = 1;
+               else
+                   longflag = 1;
+               goto nextch1;
+           case 'h':
+           case '\'':
+               /* ignore these */
+               goto nextch1;
+           case 'd':
+           case 'i':
+           case 'o':
+           case 'u':
+           case 'x':
+           case 'X':
+               if (fmtpos)
+               {
+                   PrintfArgType atype;
+
+                   if (longlongflag)
+                       atype = ATYPE_LONGLONG;
+                   else if (longflag)
+                       atype = ATYPE_LONG;
+                   else
+                       atype = ATYPE_INT;
+                   if (argtypes[fmtpos] &&
+                       argtypes[fmtpos] != atype)
+                       return -1;
+                   argtypes[fmtpos] = atype;
+                   last_dollar = Max(last_dollar, fmtpos);
+               }
+               else
+                   have_non_dollar = true;
+               break;
+           case 'c':
+               if (fmtpos)
+               {
+                   if (argtypes[fmtpos] &&
+                       argtypes[fmtpos] != ATYPE_INT)
+                       return -1;
+                   argtypes[fmtpos] = ATYPE_INT;
+                   last_dollar = Max(last_dollar, fmtpos);
+               }
+               else
+                   have_non_dollar = true;
+               break;
+           case 's':
+           case 'p':
+               if (fmtpos)
+               {
+                   if (argtypes[fmtpos] &&
+                       argtypes[fmtpos] != ATYPE_CHARPTR)
+                       return -1;
+                   argtypes[fmtpos] = ATYPE_CHARPTR;
+                   last_dollar = Max(last_dollar, fmtpos);
+               }
+               else
+                   have_non_dollar = true;
+               break;
+           case 'e':
+           case 'E':
+           case 'f':
+           case 'g':
+           case 'G':
+               if (fmtpos)
+               {
+                   if (argtypes[fmtpos] &&
+                       argtypes[fmtpos] != ATYPE_DOUBLE)
+                       return -1;
+                   argtypes[fmtpos] = ATYPE_DOUBLE;
+                   last_dollar = Max(last_dollar, fmtpos);
+               }
+               else
+                   have_non_dollar = true;
+               break;
+           case '%':
+               break;
+       }
+       /*
+        * If we finish the spec with afterstar still set, there's a
+        * non-dollar star in there.
+        */
+       if (afterstar)
+           have_non_dollar = true;
    }
-   if ((fmtparptr = malloc(sizeof(struct fmtpar *) * nargs)) == NULL)
+
+   /* Per spec, you use either all dollar or all not. */
+   if (have_dollar && have_non_dollar)
+       return -1;
+
+   /*
+    * In dollar mode, collect the arguments in physical order.
+    */
+   for (i = 1; i <= last_dollar; i++)
    {
-       fprintf(stderr, _("out of memory\n"));
-       exit(1);
+       switch (argtypes[i])
+       {
+           case ATYPE_NONE:
+               return -1;      /* invalid format */
+           case ATYPE_INT:
+               argvalues[i].i = va_arg(args, int);
+               break;
+           case ATYPE_LONG:
+               argvalues[i].l = va_arg(args, long);
+               break;
+           case ATYPE_LONGLONG:
+               argvalues[i].ll = va_arg(args, int64);
+               break;
+           case ATYPE_DOUBLE:
+               argvalues[i].d = va_arg(args, double);
+               break;
+           case ATYPE_CHARPTR:
+               argvalues[i].cptr = va_arg(args, char *);
+               break;
+       }
    }
 
-   format_save = format;
-
-   output = buffer;
-   while ((ch = *format++))
+   /*
+    * At last we can parse the format for real.
+    */
+   format = format_start;
+   while ((ch = *format++) != '\0')
    {
+       if (ch != '%')
+       {
+           dopr_outch(ch, target);
+           continue;
+       }
+       fieldwidth = precision = zpad = leftjust = forcesign = 0;
+       longflag = longlongflag = pointflag = 0;
+       fmtpos = accum = 0;
+       have_star = afterstar = false;
+   nextch2:
+       ch = *format++;
+       if (ch == '\0')
+           break;              /* illegal, but we don't complain */
        switch (ch)
        {
-           case '%':
-               leftjust = minlen = zpad = forcesign = maxwidth = 0;
-               longflag = longlongflag = pointflag = 0;
-               fmtbegin = format - 1;
-               realpos = 0;
-               position = precision = 0;
-       nextch:
-               ch = *format++;
-               switch (ch)
+           case '-':
+               leftjust = 1;
+               goto nextch2;
+           case '+':
+               forcesign = 1;
+               goto nextch2;
+           case '0':
+               /* set zero padding if no nonzero digits yet */
+               if (accum == 0 && !pointflag)
+                   zpad = '0';
+               /* FALL THRU */
+           case '1':
+           case '2':
+           case '3':
+           case '4':
+           case '5':
+           case '6':
+           case '7':
+           case '8':
+           case '9':
+               accum = accum * 10 + (ch - '0');
+               goto nextch2;
+           case '.':
+               if (have_star)
+                   have_star = false;
+               else
+                   fieldwidth = accum;
+               pointflag = 1;
+               accum = 0;
+               goto nextch2;
+           case '*':
+               if (have_dollar)
                {
-                   case '\0':
-                       goto performpr;
-                   case '-':
-                       leftjust = 1;
-                       goto nextch;
-                   case '+':
-                       forcesign = 1;
-                       goto nextch;
-                   case '0':   /* set zero padding if minlen not set */
-                       if (minlen == 0 && !pointflag)
-                           zpad = '0';
-                   case '1':
-                   case '2':
-                   case '3':
-                   case '4':
-                   case '5':
-                   case '6':
-                   case '7':
-                   case '8':
-                   case '9':
-                       if (!pointflag)
-                       {
-                           minlen = minlen * 10 + ch - '0';
-                           position = position * 10 + ch - '0';
-                       }
-                       else
+                   /* process value after reading n$ */
+                   afterstar = true;
+               }
+               else
+               {
+                   /* fetch and process value now */
+                   int     starval = va_arg(args, int);
+
+                   if (pointflag)
+                   {
+                       precision = starval;
+                       if (precision < 0)
+                           precision = 0;
+                   }
+                   else
+                   {
+                       fieldwidth = starval;
+                       if (fieldwidth < 0)
                        {
-                           maxwidth = maxwidth * 10 + ch - '0';
-                           precision = precision * 10 + ch - '0';
+                           leftjust = 1;
+                           fieldwidth = -fieldwidth;
                        }
-                       goto nextch;
-                   case '$':
-                       realpos = position;
-                       minlen = 0;
-                       goto nextch;
-                   case '*':
-                       MemSet(&fmtpar[fmtpos], 0, sizeof(fmtpar[fmtpos]));
-                       if (!pointflag)
-                           fmtpar[fmtpos].func = FMTLEN;
-                       else
-                           fmtpar[fmtpos].func = FMTWIDTH;
-                       fmtpar[fmtpos].realpos = realpos ? realpos : fmtpos;
-                       fmtpos++;
-                       goto nextch;
-                   case '.':
-                       pointflag = 1;
-                       goto nextch;
-                   case 'l':
-                       if (longflag)
-                           longlongflag = 1;
-                       else
-                           longflag = 1;
-                       goto nextch;
-                   case 'h':
-                       /* ignore */
-                       goto nextch;
-#ifdef NOT_USED
-
-                       /*
-                        * We might export this to client apps so we should
-                        * support 'qd' and 'I64d'(MinGW) also in case the
-                        * native version does.
-                        */
-                   case 'q':
-                       longlongflag = 1;
-                       longflag = 1;
-                       goto nextch;
-                   case 'I':
-                       if (*format == '6' && *(format + 1) == '4')
+                   }
+               }
+               have_star = true;
+               accum = 0;
+               goto nextch2;
+           case '$':
+               if (afterstar)
+               {
+                   /* fetch and process star value */
+                   int     starval = argvalues[accum].i;
+
+                   if (pointflag)
+                   {
+                       precision = starval;
+                       if (precision < 0)
+                           precision = 0;
+                   }
+                   else
+                   {
+                       fieldwidth = starval;
+                       if (fieldwidth < 0)
                        {
-                           format += 2;
-                           longlongflag = 1;
-                           longflag = 1;
-                           goto nextch;
+                           leftjust = 1;
+                           fieldwidth = -fieldwidth;
                        }
-                       break;
-#endif
-                   case 'u':
-                   case 'U':
-                       fmtpar[fmtpos].longflag = longflag;
-                       fmtpar[fmtpos].longlongflag = longlongflag;
-                       fmtpar[fmtpos].fmtbegin = fmtbegin;
-                       fmtpar[fmtpos].fmtend = format;
-                       fmtpar[fmtpos].base = 10;
-                       fmtpar[fmtpos].dosign = 0;
-                       fmtpar[fmtpos].forcesign = forcesign;
-                       fmtpar[fmtpos].leftjust = leftjust;
-                       fmtpar[fmtpos].minlen = minlen;
-                       fmtpar[fmtpos].zpad = zpad;
-                       fmtpar[fmtpos].func = FMTNUM_U;
-                       fmtpar[fmtpos].realpos = realpos ? realpos : fmtpos;
-                       fmtpos++;
-                       break;
-                   case 'o':
-                   case 'O':
-                       fmtpar[fmtpos].longflag = longflag;
-                       fmtpar[fmtpos].longlongflag = longlongflag;
-                       fmtpar[fmtpos].fmtbegin = fmtbegin;
-                       fmtpar[fmtpos].fmtend = format;
-                       fmtpar[fmtpos].base = 8;
-                       fmtpar[fmtpos].dosign = 0;
-                       fmtpar[fmtpos].forcesign = forcesign;
-                       fmtpar[fmtpos].leftjust = leftjust;
-                       fmtpar[fmtpos].minlen = minlen;
-                       fmtpar[fmtpos].zpad = zpad;
-                       fmtpar[fmtpos].func = FMTNUM_U;
-                       fmtpar[fmtpos].realpos = realpos ? realpos : fmtpos;
-                       fmtpos++;
-                       break;
-                   case 'd':
-                   case 'D':
-                       fmtpar[fmtpos].longflag = longflag;
-                       fmtpar[fmtpos].longlongflag = longlongflag;
-                       fmtpar[fmtpos].fmtbegin = fmtbegin;
-                       fmtpar[fmtpos].fmtend = format;
-                       fmtpar[fmtpos].base = 10;
-                       fmtpar[fmtpos].dosign = 1;
-                       fmtpar[fmtpos].forcesign = forcesign;
-                       fmtpar[fmtpos].leftjust = leftjust;
-                       fmtpar[fmtpos].minlen = minlen;
-                       fmtpar[fmtpos].zpad = zpad;
-                       fmtpar[fmtpos].func = FMTNUM;
-                       fmtpar[fmtpos].realpos = realpos ? realpos : fmtpos;
-                       fmtpos++;
-                       break;
-                   case 'x':
-                       fmtpar[fmtpos].longflag = longflag;
-                       fmtpar[fmtpos].longlongflag = longlongflag;
-                       fmtpar[fmtpos].fmtbegin = fmtbegin;
-                       fmtpar[fmtpos].fmtend = format;
-                       fmtpar[fmtpos].base = 16;
-                       fmtpar[fmtpos].dosign = 0;
-                       fmtpar[fmtpos].forcesign = forcesign;
-                       fmtpar[fmtpos].leftjust = leftjust;
-                       fmtpar[fmtpos].minlen = minlen;
-                       fmtpar[fmtpos].zpad = zpad;
-                       fmtpar[fmtpos].func = FMTNUM_U;
-                       fmtpar[fmtpos].realpos = realpos ? realpos : fmtpos;
-                       fmtpos++;
-                       break;
-                   case 'X':
-                       fmtpar[fmtpos].longflag = longflag;
-                       fmtpar[fmtpos].longlongflag = longlongflag;
-                       fmtpar[fmtpos].fmtbegin = fmtbegin;
-                       fmtpar[fmtpos].fmtend = format;
-                       fmtpar[fmtpos].base = -16;
-                       fmtpar[fmtpos].dosign = 1;
-                       fmtpar[fmtpos].forcesign = forcesign;
-                       fmtpar[fmtpos].leftjust = leftjust;
-                       fmtpar[fmtpos].minlen = minlen;
-                       fmtpar[fmtpos].zpad = zpad;
-                       fmtpar[fmtpos].func = FMTNUM_U;
-                       fmtpar[fmtpos].realpos = realpos ? realpos : fmtpos;
-                       fmtpos++;
-                       break;
-                   case 's':
-                       fmtpar[fmtpos].fmtbegin = fmtbegin;
-                       fmtpar[fmtpos].fmtend = format;
-                       fmtpar[fmtpos].leftjust = leftjust;
-                       fmtpar[fmtpos].minlen = minlen;
-                       fmtpar[fmtpos].zpad = zpad;
-                       fmtpar[fmtpos].maxwidth = maxwidth;
-                       fmtpar[fmtpos].func = FMTSTR;
-                       fmtpar[fmtpos].realpos = realpos ? realpos : fmtpos;
-                       fmtpos++;
-                       break;
-                   case 'c':
-                       fmtpar[fmtpos].fmtbegin = fmtbegin;
-                       fmtpar[fmtpos].fmtend = format;
-                       fmtpar[fmtpos].func = FMTCHAR;
-                       fmtpar[fmtpos].realpos = realpos ? realpos : fmtpos;
-                       fmtpos++;
-                       break;
-                   case 'e':
-                   case 'E':
-                   case 'f':
-                   case 'g':
-                   case 'G':
-                       fmtpar[fmtpos].fmtbegin = fmtbegin;
-                       fmtpar[fmtpos].fmtend = format;
-                       fmtpar[fmtpos].type = ch;
-                       fmtpar[fmtpos].forcesign = forcesign;
-                       fmtpar[fmtpos].leftjust = leftjust;
-                       fmtpar[fmtpos].minlen = minlen;
-                       fmtpar[fmtpos].zpad = zpad;
-                       fmtpar[fmtpos].precision = precision;
-                       fmtpar[fmtpos].pointflag = pointflag;
-                       fmtpar[fmtpos].func = FMTFLOAT;
-                       fmtpar[fmtpos].realpos = realpos ? realpos : fmtpos;
-                       fmtpos++;
-                       break;
-                   case '%':
-                       break;
-                   default:
-                       dostr("???????", 0, end, &output);
+                   }
+                   afterstar = false;
                }
+               else
+                   fmtpos = accum;
+               accum = 0;
+               goto nextch2;
+           case 'l':
+               if (longflag)
+                   longlongflag = 1;
+               else
+                   longflag = 1;
+               goto nextch2;
+           case 'h':
+           case '\'':
+               /* ignore these */
+               goto nextch2;
+           case 'd':
+           case 'i':
+               if (!have_star)
+               {
+                   if (pointflag)
+                       precision = accum;
+                   else
+                       fieldwidth = accum;
+               }
+               if (have_dollar)
+               {
+                   if (longlongflag)
+                       numvalue = argvalues[fmtpos].ll;
+                   else if (longflag)
+                       numvalue = argvalues[fmtpos].l;
+                   else
+                       numvalue = argvalues[fmtpos].i;
+               }
+               else
+               {
+                   if (longlongflag)
+                       numvalue = va_arg(args, int64);
+                   else if (longflag)
+                       numvalue = va_arg(args, long);
+                   else
+                       numvalue = va_arg(args, int);
+               }
+               fmtint(numvalue, ch, forcesign, leftjust, fieldwidth, zpad,
+                      precision, pointflag, target);
                break;
-           default:
-               dopr_outch(ch, end, &output);
-               break;
-       }
-   }
-
-performpr:
-   /* reorder pointers */
-   for (i = 1; i < fmtpos; i++)
-       fmtparptr[i] = &fmtpar[fmtpar[i].realpos];
-
-   /* assign values */
-   for (i = 1; i < fmtpos; i++)
-   {
-       switch (fmtparptr[i]->func)
-       {
-           case FMTSTR:
-               fmtparptr[i]->value = va_arg(args, char *);
-               break;
-           case FMTNUM:
-               if (fmtparptr[i]->longflag)
+           case 'o':
+           case 'u':
+           case 'x':
+           case 'X':
+               if (!have_star)
+               {
+                   if (pointflag)
+                       precision = accum;
+                   else
+                       fieldwidth = accum;
+               }
+               if (have_dollar)
                {
-                   if (fmtparptr[i]->longlongflag)
-                       fmtparptr[i]->numvalue = va_arg(args, int64);
+                   if (longlongflag)
+                       numvalue = (uint64) argvalues[fmtpos].ll;
+                   else if (longflag)
+                       numvalue = (unsigned long) argvalues[fmtpos].l;
                    else
-                       fmtparptr[i]->numvalue = va_arg(args, long);
+                       numvalue = (unsigned int) argvalues[fmtpos].i;
                }
                else
-                   fmtparptr[i]->numvalue = va_arg(args, int);
+               {
+                   if (longlongflag)
+                       numvalue = (uint64) va_arg(args, int64);
+                   else if (longflag)
+                       numvalue = (unsigned long) va_arg(args, long);
+                   else
+                       numvalue = (unsigned int) va_arg(args, int);
+               }
+               fmtint(numvalue, ch, forcesign, leftjust, fieldwidth, zpad,
+                      precision, pointflag, target);
                break;
-           case FMTNUM_U:
-               if (fmtparptr[i]->longflag)
+           case 'c':
+               if (!have_star)
                {
-                   if (fmtparptr[i]->longlongflag)
-                       fmtparptr[i]->numvalue = va_arg(args, uint64);
+                   if (pointflag)
+                       precision = accum;
                    else
-                       fmtparptr[i]->numvalue = va_arg(args, unsigned long);
+                       fieldwidth = accum;
                }
+               if (have_dollar)
+                   cvalue = (unsigned char) argvalues[fmtpos].i;
                else
-                   fmtparptr[i]->numvalue = va_arg(args, unsigned int);
+                   cvalue = (unsigned char) va_arg(args, int);
+               fmtchar(cvalue, leftjust, fieldwidth, target);
                break;
-           case FMTFLOAT:
-               fmtparptr[i]->fvalue = va_arg(args, double);
+           case 's':
+               if (!have_star)
+               {
+                   if (pointflag)
+                       precision = accum;
+                   else
+                       fieldwidth = accum;
+               }
+               if (have_dollar)
+                   strvalue = argvalues[fmtpos].cptr;
+               else
+                   strvalue = va_arg(args, char *);
+               fmtstr(strvalue, leftjust, fieldwidth, precision, pointflag,
+                      target);
                break;
-           case FMTCHAR:
-               fmtparptr[i]->charvalue = va_arg(args, int);
+           case 'p':
+               /* fieldwidth/leftjust are ignored ... */
+               if (have_dollar)
+                   strvalue = argvalues[fmtpos].cptr;
+               else
+                   strvalue = va_arg(args, char *);
+               fmtptr((void *) strvalue, target);
                break;
-           case FMTLEN:
+           case 'e':
+           case 'E':
+           case 'f':
+           case 'g':
+           case 'G':
+               if (!have_star)
                {
-                   int         minlen = va_arg(args, int);
-                   int         leftjust = 0;
-
-                   if (minlen < 0)
-                   {
-                       minlen = -minlen;
-                       leftjust = 1;
-                   }
-                   if (i + 1 < fmtpos && fmtparptr[i + 1]->func != FMTWIDTH)
-                   {
-                       fmtparptr[i + 1]->minlen = minlen;
-                       fmtparptr[i + 1]->leftjust |= leftjust;
-                   }
-                   /* For "%*.*f", use the second arg */
-                   if (i + 2 < fmtpos && fmtparptr[i + 1]->func == FMTWIDTH)
-                   {
-                       fmtparptr[i + 2]->minlen = minlen;
-                       fmtparptr[i + 2]->leftjust |= leftjust;
-                   }
+                   if (pointflag)
+                       precision = accum;
+                   else
+                       fieldwidth = accum;
                }
+               if (have_dollar)
+                   fvalue = argvalues[fmtpos].d;
+               else
+                   fvalue = va_arg(args, double);
+               fmtfloat(fvalue, ch, forcesign, leftjust,
+                        fieldwidth, zpad,
+                        precision, pointflag,
+                        target);
                break;
-           case FMTWIDTH:
-               if (i + 1 < fmtpos)
-                   fmtparptr[i + 1]->maxwidth = fmtparptr[i + 1]->precision =
-                       va_arg(args, int);
+           case '%':
+               dopr_outch('%', target);
                break;
        }
    }
 
-   /* do the output */
-   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]->leftjust,
-                              fmtparptr[i]->minlen, fmtparptr[i]->maxwidth,
-                              end, &output);
-                       break;
-                   case FMTNUM:
-                   case FMTNUM_U:
-                       fmtint(fmtparptr[i]->numvalue, fmtparptr[i]->base,
-                              fmtparptr[i]->dosign, fmtparptr[i]->forcesign,
-                              fmtparptr[i]->leftjust, fmtparptr[i]->minlen,
-                              fmtparptr[i]->zpad, end, &output);
-                       break;
-                   case FMTFLOAT:
-                       fmtfloat(fmtparptr[i]->fvalue, fmtparptr[i]->type,
-                            fmtparptr[i]->forcesign, fmtparptr[i]->leftjust,
-                                fmtparptr[i]->minlen, fmtparptr[i]->zpad,
-                           fmtparptr[i]->precision, fmtparptr[i]->pointflag,
-                                end, &output);
-                       break;
-                   case FMTCHAR:
-                       dopr_outch(fmtparptr[i]->charvalue, end, &output);
-                       break;
-               }
-               format = fmtpar[i].fmtend;
-               goto nochar;
-           }
-       }
-       dopr_outch(ch, end, &output);
-nochar:
-       /* nothing */
-       ;                       /* semicolon required because a goto has to be
-                                * attached to a statement */
-   }
-   *output = '\0';
+   return 0;
+}
+
+static size_t
+pg_strnlen(const char *str, size_t maxlen)
+{
+   const char *p = str;
 
-   free(fmtpar);
-   free(fmtparptr);
+   while (maxlen-- > 0 && *p)
+       p++;
+   return p - str;
 }
 
 static void
-fmtstr(char *value, int leftjust, int minlen, int maxwidth, char *end,
-      char **output)
+fmtstr(char *value, int leftjust, int minlen, int maxwidth,
+      int pointflag, PrintfTarget *target)
 {
    int         padlen,
                vallen;         /* amount to pad */
 
-   if (value == NULL)
-       value = "<NULL>";
-
-   vallen = strlen(value);
-   if (maxwidth && vallen > maxwidth)
-       vallen = maxwidth;
+   /*
+    * If a maxwidth (precision) is specified, we must not fetch more bytes
+    * than that.
+    */
+   if (pointflag)
+       vallen = pg_strnlen(value, maxwidth);
+   else
+       vallen = strlen(value);
 
    adjust_padlen(minlen, vallen, leftjust, &padlen);
 
    while (padlen > 0)
    {
-       dopr_outch(' ', end, output);
+       dopr_outch(' ', target);
        --padlen;
    }
-   dostr(value, maxwidth, end, output);
 
-   trailing_pad(&padlen, end, output);
+   dostr(value, vallen, target);
+
+   trailing_pad(&padlen, target);
 }
 
 static void
-fmtint(int64 value, int base, int dosign, int forcesign, int leftjust,
-      int minlen, int zpad, char *end, char **output)
+fmtptr(void *value, PrintfTarget *target)
 {
+   int         vallen;
+   char        convert[64];
+
+   /* we rely on regular C library's sprintf to do the basic conversion */
+   vallen = sprintf(convert, "%p", value);
+
+   dostr(convert, vallen, target);
+}
+
+static void
+fmtint(int64 value, char type, int forcesign, int leftjust,
+      int minlen, int zpad, int precision, int pointflag,
+      PrintfTarget *target)
+{
+   uint64      base;
+   int         dosign;
+   const char *cvt = "0123456789abcdef";
    int         signvalue = 0;
    char        convert[64];
    int         vallen = 0;
    int         padlen = 0;     /* amount to pad */
-   int         caps = 0;
+   int         zeropad;        /* extra leading zeroes */
 
-   /* Handle +/- and %X (uppercase hex) */
+   switch (type)
+   {
+       case 'd':
+       case 'i':
+           base = 10;
+           dosign = 1;
+           break;
+       case 'o':
+           base = 8;
+           dosign = 0;
+           break;
+       case 'u':
+           base = 10;
+           dosign = 0;
+           break;
+       case 'x':
+           base = 16;
+           dosign = 0;
+           break;
+       case 'X':
+           cvt = "0123456789ABCDEF";
+           base = 16;
+           dosign = 0;
+           break;
+       default:
+           return;             /* keep compiler quiet */
+   }
+
+   /* Handle +/- */
    if (dosign && adjust_sign((value < 0), forcesign, &signvalue))
        value = -value;
-   if (base < 0)
+
+   /*
+    * SUS: the result of converting 0 with an explicit precision of 0 is no
+    * characters
+    */
+   if (value == 0 && pointflag && precision == 0)
+       vallen = 0;
+   else
    {
-       caps = 1;
-       base = -base;
+       /* make integer string */
+       uint64  uvalue = (uint64) value;
+
+       do
+       {
+           convert[vallen++] = cvt[uvalue % base];
+           uvalue = uvalue / base;
+       } while (uvalue);
    }
 
-   /* make integer string */
-   do
-   {
-       convert[vallen++] = (caps ? "0123456789ABCDEF" : "0123456789abcdef")
-           [value % (unsigned) base];
-       value = (value / (unsigned) base);
-   } while (value);
-   convert[vallen] = 0;
+   zeropad = Max(0, precision - vallen);
 
-   adjust_padlen(minlen, vallen, leftjust, &padlen);
+   adjust_padlen(minlen, vallen + zeropad, leftjust, &padlen);
+
+   leading_pad(zpad, &signvalue, &padlen, target);
 
-   leading_pad(zpad, &signvalue, &padlen, end, output);
+   while (zeropad-- > 0)
+       dopr_outch('0', target);
 
    while (vallen > 0)
-       dopr_outch(convert[--vallen], end, output);
+       dopr_outch(convert[--vallen], target);
 
-   trailing_pad(&padlen, end, output);
+   trailing_pad(&padlen, target);
+}
+
+static void
+fmtchar(int value, int leftjust, int minlen, PrintfTarget *target)
+{
+   int         padlen = 0;     /* amount to pad */
+
+   adjust_padlen(minlen, 1, leftjust, &padlen);
+
+   while (padlen > 0)
+   {
+       dopr_outch(' ', target);
+       --padlen;
+   }
+
+   dopr_outch(value, target);
+
+   trailing_pad(&padlen, target);
 }
 
 static void
 fmtfloat(double value, char type, int forcesign, int leftjust,
-        int minlen, int zpad, int precision, int pointflag, char *end,
-        char **output)
+        int minlen, int zpad, int precision, int pointflag,
+        PrintfTarget *target)
 {
    int         signvalue = 0;
    int         vallen;
@@ -676,37 +900,51 @@ fmtfloat(double value, char type, int forcesign, int leftjust,
 
    adjust_padlen(minlen, vallen, leftjust, &padlen);
 
-   leading_pad(zpad, &signvalue, &padlen, end, output);
+   leading_pad(zpad, &signvalue, &padlen, target);
 
-   dostr(convert, 0, end, output);
+   dostr(convert, vallen, target);
 
-   trailing_pad(&padlen, end, output);
+   trailing_pad(&padlen, target);
 }
 
 static void
-dostr(char *str, int cut, char *end, char **output)
+dostr(const char *str, int slen, PrintfTarget *target)
 {
-   if (cut)
-       while (*str && cut-- > 0)
-           dopr_outch(*str++, end, output);
-   else
-       while (*str)
-           dopr_outch(*str++, end, output);
+   while (slen > 0)
+   {
+       int     avail;
+
+       if (target->bufend != NULL)
+           avail = target->bufend - target->bufptr;
+       else 
+           avail = slen;
+       if (avail <= 0)
+       {
+           /* buffer full, can we dump to stream? */
+           if (target->stream == NULL)
+               return;             /* no, lose the data */
+           flushbuffer(target);
+           continue;
+       }
+       avail = Min(avail, slen);
+       memmove(target->bufptr, str, avail);
+       target->bufptr += avail;
+       str += avail;
+       slen -= avail;
+   }
 }
 
 static void
-dopr_outch(int c, char *end, char **output)
+dopr_outch(int c, PrintfTarget *target)
 {
-#ifdef NOT_USED
-   if (iscntrl((unsigned char) c) && c != '\n' && c != '\t')
+   if (target->bufend != NULL && target->bufptr >= target->bufend)
    {
-       c = '@' + (c & 0x1F);
-       if (end == 0 || *output < end)
-           *(*output)++ = '^';
+       /* buffer full, can we dump to stream? */
+       if (target->stream == NULL)
+           return;             /* no, lose the data */
+       flushbuffer(target);
    }
-#endif
-   if (end == 0 || *output < end)
-       *(*output)++ = c;
+   *(target->bufptr++) = c;
 }
 
 
@@ -731,49 +969,49 @@ adjust_padlen(int minlen, int vallen, int leftjust, int *padlen)
    if (*padlen < 0)
        *padlen = 0;
    if (leftjust)
-       *padlen = -*padlen;
+       *padlen = -(*padlen);
 }
 
 
 static void
-leading_pad(int zpad, int *signvalue, int *padlen, char *end, char **output)
+leading_pad(int zpad, int *signvalue, int *padlen, PrintfTarget *target)
 {
    if (*padlen > 0 && zpad)
    {
        if (*signvalue)
        {
-           dopr_outch(*signvalue, end, output);
-           --*padlen;
+           dopr_outch(*signvalue, target);
+           --(*padlen);
            *signvalue = 0;
        }
        while (*padlen > 0)
        {
-           dopr_outch(zpad, end, output);
-           --*padlen;
+           dopr_outch(zpad, target);
+           --(*padlen);
        }
    }
-   while (*padlen > 0 + (*signvalue != 0))
+   while (*padlen > (*signvalue != 0))
    {
-       dopr_outch(' ', end, output);
-       --*padlen;
+       dopr_outch(' ', target);
+       --(*padlen);
    }
    if (*signvalue)
    {
-       dopr_outch(*signvalue, end, output);
+       dopr_outch(*signvalue, target);
        if (*padlen > 0)
-           --* padlen;
-       if (padlen < 0)
-           ++padlen;
+           --(*padlen);
+       else if (*padlen < 0)
+           ++(*padlen);
    }
 }
 
 
 static void
-trailing_pad(int *padlen, char *end, char **output)
+trailing_pad(int *padlen, PrintfTarget *target)
 {
    while (*padlen < 0)
    {
-       dopr_outch(' ', end, output);
-       ++*padlen;
+       dopr_outch(' ', target);
+       ++(*padlen);
    }
 }