]> granicus.if.org Git - postgresql/commitdiff
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);
        }
 }