snprintf.cc

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/*
 * Copyright Patrick Powell 1995
 * This code is based on code written by Patrick Powell (papowell@astart.com)
 * It may be used for any purpose as long as this notice remains intact
 * on all source code distributions
 */

/**************************************************************
 * Original:
 * Patrick Powell Tue Apr 11 09:48:21 PDT 1995
 * 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...
 *
 * 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 nast effects.
 *
 * More Recently:
 *  Brandon Long <blong@fiction.net> 9/15/96 for mutt 0.43
 *  This was ugly.  It is still ugly.  I opted out of floating point
 *  numbers, but the formatter understands just about everything
 *  from the normal C string format, at least as far as I can tell from
 *  the Solaris 2.5 printf(3S) man page.
 *
 *  Brandon Long <blong@fiction.net> 10/22/97 for mutt 0.87.1
 *    Ok, added some minimal floating point support, which means this
 *    probably requires libm on most operating systems.  Don't yet
 *    support the exponent (e,E) and sigfig (g,G).  Also, fmtint()
 *    was pretty badly broken, it just wasn't being exercised in ways
 *    which showed it, so that's been fixed.  Also, formated the code
 *    to mutt conventions, and removed dead code left over from the
 *    original.  Also, there is now a builtin-test, just compile with:
 *           gcc -DTEST_SNPRINTF -o snprintf snprintf.c -lm
 *    and run snprintf for results.
 * 
 *  Thomas Roessler <roessler@guug.de> 01/27/98 for mutt 0.89i
 *    The PGP code was using unsigned hexadecimal formats. 
 *    Unfortunately, unsigned formats simply didn't work.
 *
 *  Michael Elkins <me@cs.hmc.edu> 03/05/98 for mutt 0.90.8
 *    The original code assumed that both snprintf() and vsnprintf() were
 *    missing.  Some systems only have snprintf() but not vsnprintf(), so
 *    the code is now broken down under HAVE_SNPRINTF and HAVE_VSNPRINTF.
 *
 *  Andrew Tridgell (tridge@samba.org) Oct 1998
 *    fixed handling of %.0f
 *    added test for HAVE_LONG_DOUBLE
 *
 * tridge@samba.org, idra@samba.org, April 2001
 *    got rid of fcvt code (twas buggy and made testing harder)
 *    added C99 semantics
 *
 * HT authors
 *    * ht_snprintf/ht_vsnprintf return number of characters actually
 *      written instead of the number of characters that would
 *      have been written.
 *    * added '%y' to allow object output using Object's toString() method.
 *    * added '%q[dioux]' for formatting qwords.
 *    * added '%b' for formatting in binary notation.
 **************************************************************/

#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <sys/types.h>

#include "common.h"
#include "global.h"
#include "tools.h"

#ifndef NO_CONFIG_H /* for some tests */
#include "config.h"
#endif


#ifdef HAVE_LONG_DOUBLE
#define LDOUBLE long double
#else
#define LDOUBLE double
#endif

#ifdef HAVE_LONG_LONG
#define LLONG long long
#else
#define LLONG long
#endif

static size_t dopr(char *buffer, size_t maxlen, const char *format, 
                            va_list args);
static void fmtstr(char *buffer, size_t *currlen, size_t maxlen,
                                char *value, int flags, int min, int max);
static void fmtint(char *buffer, size_t *currlen, size_t maxlen,
                                long value, int base, int min, int max, int flags);
static void fmtqword(char *buffer, size_t *currlen, size_t maxlen,
                                sint64 value, int base, int min, int max, int flags);
static void fmtfp(char *buffer, size_t *currlen, size_t maxlen,
                            LDOUBLE fvalue, int min, int max, int flags);
static void dopr_outch(char *buffer, size_t *currlen, size_t maxlen, char c);

/*
 * dopr(): poor man's version of doprintf
 */

/* format read states */
#define DP_S_DEFAULT 0
#define DP_S_FLAGS   1
#define DP_S_MIN     2
#define DP_S_DOT     3
#define DP_S_MAX     4
#define DP_S_MOD     5
#define DP_S_CONV    6
#define DP_S_DONE    7

/* format flags - Bits */
#define DP_F_MINUS      (1 << 0)
#define DP_F_PLUS       (1 << 1)
#define DP_F_SPACE      (1 << 2)
#define DP_F_NUM        (1 << 3)
#define DP_F_ZERO       (1 << 4)
#define DP_F_UP         (1 << 5)
#define DP_F_UNSIGNED   (1 << 6)

/* Conversion Flags */
#define DP_C_SHORT   1
#define DP_C_LONG    2
#define DP_C_LDOUBLE 3
#define DP_C_LLONG   4
#define DP_C_QWORD   5

#define char_to_int(p) ((p)- '0')
#ifndef MAX
#define MAX(p,q) (((p) >= (q)) ? (p) : (q))
#endif

static size_t dopr(char *buffer, size_t maxlen, const char *format, va_list args)
{
           char ch;
           LLONG value;
           LDOUBLE fvalue;
           char *strvalue;
           int min;
           int max;
           int state;
           int flags;
           int cflags;
           size_t currlen;
           
           state = DP_S_DEFAULT;
           currlen = flags = cflags = min = 0;
           max = -1;
           ch = *format++;
           
           while (state != DP_S_DONE) {
                         if (ch == '\0') 
                                    state = DP_S_DONE;

                         switch(state) {
                         case DP_S_DEFAULT:
                                    if (ch == '%') 
                                                  state = DP_S_FLAGS;
                                    else 
                                                  dopr_outch (buffer, &currlen, maxlen, ch);
                                    ch = *format++;
                                    break;
                         case DP_S_FLAGS:
                                    switch (ch) {
                                    case '-':
                                                  flags |= DP_F_MINUS;
                                                  ch = *format++;
                                                  break;
                                    case '+':
                                                  flags |= DP_F_PLUS;
                                                  ch = *format++;
                                                  break;
                                    case ' ':
                                                  flags |= DP_F_SPACE;
                                                  ch = *format++;
                                                  break;
                                    case '#':
                                                  flags |= DP_F_NUM;
                                                  ch = *format++;
                                                  break;
                                    case '0':
                                                  flags |= DP_F_ZERO;
                                                  ch = *format++;
                                                  break;
                                    default:
                                                  state = DP_S_MIN;
                                                  break;
                                    }
                                    break;
                         case DP_S_MIN:
                                    if (isdigit((unsigned char)ch)) {
                                                  min = 10*min + char_to_int (ch);
                                                  ch = *format++;
                                    } else if (ch == '*') {
                                                  min = va_arg (args, int);
                                                  ch = *format++;
                                                  state = DP_S_DOT;
                                    } else {
                                                  state = DP_S_DOT;
                                    }
                                    break;
                         case DP_S_DOT:
                                    if (ch == '.') {
                                                  state = DP_S_MAX;
                                                  ch = *format++;
                                    } else { 
                                                  state = DP_S_MOD;
                                    }
                                    break;
                         case DP_S_MAX:
                                    if (isdigit((unsigned char)ch)) {
                                                  if (max < 0)
                                                                max = 0;
                                                  max = 10*max + char_to_int (ch);
                                                  ch = *format++;
                                    } else if (ch == '*') {
                                                  max = va_arg (args, int);
                                                  ch = *format++;
                                                  state = DP_S_MOD;
                                    } else {
                                                  state = DP_S_MOD;
                                    }
                                    break;
                         case DP_S_MOD:
                                    switch (ch) {
                                    case 'h':
                                                  cflags = DP_C_SHORT;
                                                  ch = *format++;
                                                  break;
                                    case 'l':
                                                  cflags = DP_C_LONG;
                                                  ch = *format++;
                                                  if (ch == 'l') {        /* It's a long long */
                                                                cflags = DP_C_LLONG;
                                                                ch = *format++;
                                                  }
                                                  break;
                                    case 'L':
                                                  cflags = DP_C_LDOUBLE;
                                                  ch = *format++;
                                                  break;
                                    case 'q':
                                                  cflags = DP_C_QWORD;
                                                  ch = *format++;
                                                  break;
                                    default:
                                                  break;
                                    }
                                    state = DP_S_CONV;
                                    break;
                         case DP_S_CONV:
                                    switch (ch) {
                                    case 'b':
                                                  flags |= DP_F_UNSIGNED;
                                                  if (cflags == DP_C_SHORT)
                                                                value = va_arg (args, unsigned int);
                                                  else if (cflags == DP_C_LONG)
                                                                value = (long)va_arg (args, unsigned long int);
                                                  else if (cflags == DP_C_LLONG)
                                                                value = (LLONG)va_arg (args, unsigned LLONG);
                                                  else if (cflags == DP_C_QWORD) {
                                                          sint64 *q = va_arg (args, sint64 *);
                                                          fmtqword(buffer, &currlen, maxlen, *q, 2, min, max, flags);
                                                          break;
                                                  } else
                                                          value = (long)va_arg (args, unsigned int);
                                                  fmtint (buffer, &currlen, maxlen, value, 2, min, max, flags);
                                                  break;
                                    case 'd':
                                    case 'i':
                                                  if (cflags == DP_C_SHORT) 
                                                                value = va_arg (args, int);
                                                  else if (cflags == DP_C_LONG)
                                                                value = va_arg (args, long int);
                                                  else if (cflags == DP_C_LLONG)
                                                                value = va_arg (args, LLONG);
                                                  else if (cflags == DP_C_QWORD) {
                                                          sint64 *q = va_arg (args, sint64 *);
                                                          fmtqword(buffer, &currlen, maxlen, *q, 10, min, max, flags);
                                                          break;
                                                  } else
                                                                value = va_arg (args, int);
                                                  fmtint (buffer, &currlen, maxlen, value, 10, min, max, flags);
                                                  break;
                                    case 'o':
                                                  flags |= DP_F_UNSIGNED;
                                                  if (cflags == DP_C_SHORT)
                                                                value = va_arg (args, unsigned int);
                                                  else if (cflags == DP_C_LONG)
                                                                value = (long)va_arg (args, unsigned long int);
                                                  else if (cflags == DP_C_LLONG)
                                                                value = (long)va_arg (args, unsigned LLONG);
                                                  else if (cflags == DP_C_QWORD) {
                                                          sint64 *q = va_arg (args, sint64 *);
                                                          fmtqword(buffer, &currlen, maxlen, *q, 8, min, max, flags);
                                                          break;
                                                  } else
                                                                value = (long)va_arg (args, unsigned int);
                                                  fmtint (buffer, &currlen, maxlen, value, 8, min, max, flags);
                                                  break;
                                    case 'u':
                                                  flags |= DP_F_UNSIGNED;
                                                  if (cflags == DP_C_SHORT)
                                                                value = va_arg (args, unsigned int);
                                                  else if (cflags == DP_C_LONG)
                                                                value = (long)va_arg (args, unsigned long int);
                                                  else if (cflags == DP_C_LLONG)
                                                                value = (LLONG)va_arg (args, unsigned LLONG);
                                                  else if (cflags == DP_C_QWORD) {
                                                          sint64 *q = va_arg (args, sint64 *);
                                                          fmtqword(buffer, &currlen, maxlen, *q, 10, min, max, flags);
                                                          break;
                                                  } else
                                                                value = (long)va_arg (args, unsigned int);
                                                  fmtint (buffer, &currlen, maxlen, value, 10, min, max, flags);
                                                  break;
                                    case 'X':
                                                  flags |= DP_F_UP;
                                    case 'x':
                                                  flags |= DP_F_UNSIGNED;
                                                  if (cflags == DP_C_SHORT)
                                                                value = va_arg (args, unsigned int);
                                                  else if (cflags == DP_C_LONG)
                                                                value = (long)va_arg (args, unsigned long int);
                                                  else if (cflags == DP_C_LLONG)
                                                                value = (LLONG)va_arg (args, unsigned LLONG);
                                                  else if (cflags == DP_C_QWORD) {
                                                          sint64 *q = va_arg (args, sint64 *);
                                                          fmtqword(buffer, &currlen, maxlen, *q, 16, min, max, flags);
                                                          break;
                                                  } else
                                                                value = (long)va_arg (args, unsigned int);
                                                  fmtint (buffer, &currlen, maxlen, value, 16, min, max, flags);
                                                  break;
                                    case 'f':
                                                  if (cflags == DP_C_LDOUBLE)
                                                                fvalue = va_arg (args, LDOUBLE);
                                                  else
                                                                fvalue = va_arg (args, double);
                                                  /* um, floating point? */
                                                  fmtfp (buffer, &currlen, maxlen, fvalue, min, max, flags);
                                                  break;
                                    case 'E':
                                                  flags |= DP_F_UP;
                                    case 'e':
                                                  if (cflags == DP_C_LDOUBLE)
                                                                fvalue = va_arg (args, LDOUBLE);
                                                  else
                                                                fvalue = va_arg (args, double);
                                                  break;
                                    case 'G':
                                                  flags |= DP_F_UP;
                                    case 'g':
                                                  if (cflags == DP_C_LDOUBLE)
                                                                fvalue = va_arg (args, LDOUBLE);
                                                  else
                                                                fvalue = va_arg (args, double);
                                                  break;
                                    case 'c':
                                                  dopr_outch (buffer, &currlen, maxlen, va_arg (args, int));
                                                  break;
                                    case 's':
                                                  strvalue = va_arg (args, char *);
                                                  if (!strvalue) strvalue = "(null)";
                                                  if (max == -1) {
                                                                max = strlen(strvalue);
                                                  }
                                                  if (min > 0 && max >= 0 && min > max) max = min;
                                                  fmtstr (buffer, &currlen, maxlen, strvalue, flags, min, max);
                                                  break;
                                    case 'p':
                                                  strvalue = va_arg (args, char *);
                                                  fmtint (buffer, &currlen, maxlen, (long) strvalue, 16, min, max, flags);
                                                  break;
                                    case 'n':
                                                  if (cflags == DP_C_SHORT) {
                                                                short int *num;
                                                                num = va_arg (args, short int *);
                                                                *num = currlen;
                                                  } else if (cflags == DP_C_LONG) {
                                                                long int *num;
                                                                num = va_arg (args, long int *);
                                                                *num = (long int)currlen;
                                                  } else if (cflags == DP_C_LLONG) {
                                                                LLONG *num;
                                                                num = va_arg (args, LLONG *);
                                                                *num = (LLONG)currlen;
                                                  } else {
                                                                int *num;
                                                                num = va_arg (args, int *);
                                                                *num = currlen;
                                                  }
                                                  break;
                                    case '%':
                                                  dopr_outch (buffer, &currlen, maxlen, ch);
                                                  break;
                                    case 'w':
                                                  /* not supported yet, treat as next char */
                                                  ch = *format++;
                                                  break;
                                    case 'y':
                                                  /* object */
                                                  strvalue = va_arg (args, char *);
                                                  currlen += ((Object*)strvalue)->toString(buffer+currlen, maxlen - currlen);
                                                  break;
                                    default:
                                                  /* Unknown, skip */
                                                  break;
                                    }
                                    ch = *format++;
                                    state = DP_S_DEFAULT;
                                    flags = cflags = min = 0;
                                    max = -1;
                                    break;
                         case DP_S_DONE:
                                    break;
                         default:
                                    /* hmm? */
                                    break; /* some picky compilers need this */
                         }
           }
           if (maxlen != 0) {
                         if (currlen < maxlen - 1) 
                                    buffer[currlen] = '\0';
                         else if (maxlen > 0) 
                                    buffer[maxlen - 1] = '\0';
           }
           
           return currlen;
}

static void fmtstr(char *buffer, size_t *currlen, size_t maxlen,
                                char *value, int flags, int min, int max)
{
           int padlen, strln;     /* amount to pad */
           int cnt = 0;

#ifdef DEBUG_SNPRINTF
           printf("fmtstr min=%d max=%d s=[%s]\n", min, max, value);
#endif
           if (value == 0) {
                         value = "<NULL>";
           }

           for (strln = 0; value[strln]; ++strln); /* strlen */
           padlen = min - strln;
           if (padlen < 0) 
                         padlen = 0;
           if (flags & DP_F_MINUS) 
                         padlen = -padlen; /* Left Justify */
           
           while ((padlen > 0) && (cnt < max)) {
                         dopr_outch (buffer, currlen, maxlen, ' ');
                         --padlen;
                         ++cnt;
           }
           while (*value && (cnt < max)) {
                         dopr_outch (buffer, currlen, maxlen, *value++);
                         ++cnt;
           }
           while ((padlen < 0) && (cnt < max)) {
                         dopr_outch (buffer, currlen, maxlen, ' ');
                         ++padlen;
                         ++cnt;
           }
}

/* Have to handle DP_F_NUM (ie 0x and 0 alternates) */

static void fmtint(char *buffer, size_t *currlen, size_t maxlen,
                                long value, int base, int min, int max, int flags)
{
#define MAX_CONVERT_PLACES 40
           int signvalue = 0;
           unsigned long uvalue;
           char convert[MAX_CONVERT_PLACES];
           int place = 0;
           int spadlen = 0; /* amount to space pad */
           int zpadlen = 0; /* amount to zero pad */
           int caps = 0;
           
           if (max < 0)
                         max = 0;
           
           uvalue = value;
           
           if(!(flags & DP_F_UNSIGNED)) {
                         if( value < 0 ) {
                                    signvalue = '-';
                                    uvalue = -value;
                         } else {
                                    if (flags & DP_F_PLUS)  /* Do a sign (+/i) */
                                                  signvalue = '+';
                                    else if (flags & DP_F_SPACE)
                                                  signvalue = ' ';
                         }
           }
  
           if (flags & DP_F_UP) caps = 1; /* Should characters be upper case? */

           do {
                         convert[place++] =
                                    (caps? "0123456789ABCDEF":"0123456789abcdef")
                                    [uvalue % (unsigned)base  ];
                         uvalue = (uvalue / (unsigned)base );
           } while(uvalue && (place < MAX_CONVERT_PLACES));
           if (place == MAX_CONVERT_PLACES) place--;
           convert[place] = 0;

           zpadlen = max - place;
           spadlen = min - MAX (max, place) - (signvalue ? 1 : 0);
           if (zpadlen < 0) zpadlen = 0;
           if (spadlen < 0) spadlen = 0;
           if (flags & DP_F_ZERO) {
                         zpadlen = MAX(zpadlen, spadlen);
                         spadlen = 0;
           }
           if (flags & DP_F_MINUS) 
                         spadlen = -spadlen; /* Left Justifty */

#ifdef DEBUG_SNPRINTF
           printf("zpad: %d, spad: %d, min: %d, max: %d, place: %d\n",
                        zpadlen, spadlen, min, max, place);
#endif

           /* Spaces */
           while (spadlen > 0) {
                         dopr_outch (buffer, currlen, maxlen, ' ');
                         --spadlen;
           }

           /* Sign */
           if (signvalue) 
                         dopr_outch (buffer, currlen, maxlen, signvalue);

           /* Zeros */
           if (zpadlen > 0) {
                         while (zpadlen > 0) {
                                    dopr_outch (buffer, currlen, maxlen, '0');
                                    --zpadlen;
                         }
           }

           /* Digits */
           while (place > 0) 
                         dopr_outch (buffer, currlen, maxlen, convert[--place]);
  
           /* Left Justified spaces */
           while (spadlen < 0) {
                         dopr_outch (buffer, currlen, maxlen, ' ');
                         ++spadlen;
           }
}

static void fmtqword(char *buffer, size_t *currlen, size_t maxlen,
                                sint64 value, int base, int min, int max, int flags)
{
#undef MAX_CONVERT_PLACES
#define MAX_CONVERT_PLACES 80
           int signvalue = 0;
           uint64 uvalue;
           char convert[MAX_CONVERT_PLACES];
           int place = 0;
           int spadlen = 0; /* amount to space pad */
           int zpadlen = 0; /* amount to zero pad */
           int caps = 0;
           
           if (max < 0)
                         max = 0;
           
           uvalue = to_uint64(value);
           
           if (!(flags & DP_F_UNSIGNED)) {
                         if (value < to_sint64(0)) {
                                    signvalue = '-';
                                    uvalue = to_uint64(-value);
                         } else {
                                    if (flags & DP_F_PLUS)  /* Do a sign (+/i) */
                                                  signvalue = '+';
                                    else if (flags & DP_F_SPACE)
                                                  signvalue = ' ';
                         }
           }
  
           if (flags & DP_F_UP) caps = 1; /* Should characters be upper case? */

           do {
                         qword uv = uvalue % to_qword((unsigned)base);
                         convert[place++] =
                                    (caps? "0123456789ABCDEF":"0123456789abcdef")
                                    [uv.lo];
                         uvalue = (uvalue / to_qword((unsigned)base));
           } while ((uvalue != to_qword(0)) && (place < MAX_CONVERT_PLACES));
           if (place == MAX_CONVERT_PLACES) place--;
           convert[place] = 0;

           zpadlen = max - place;
           spadlen = min - MAX (max, place) - (signvalue ? 1 : 0);
           if (zpadlen < 0) zpadlen = 0;
           if (spadlen < 0) spadlen = 0;
           if (flags & DP_F_ZERO) {
                         zpadlen = MAX(zpadlen, spadlen);
                         spadlen = 0;
           }
           if (flags & DP_F_MINUS) 
                         spadlen = -spadlen; /* Left Justifty */

#ifdef DEBUG_SNPRINTF
           printf("zpad: %d, spad: %d, min: %d, max: %d, place: %d\n",
                        zpadlen, spadlen, min, max, place);
#endif

           /* Spaces */
           while (spadlen > 0) {
                         dopr_outch (buffer, currlen, maxlen, ' ');
                         --spadlen;
           }

           /* Sign */
           if (signvalue) 
                         dopr_outch (buffer, currlen, maxlen, signvalue);

           /* Zeros */
           if (zpadlen > 0) {
                         while (zpadlen > 0) {
                                    dopr_outch (buffer, currlen, maxlen, '0');
                                    --zpadlen;
                         }
           }

           /* Digits */
           while (place > 0) 
                         dopr_outch (buffer, currlen, maxlen, convert[--place]);
  
           /* Left Justified spaces */
           while (spadlen < 0) {
                         dopr_outch (buffer, currlen, maxlen, ' ');
                         ++spadlen;
           }
}

static LDOUBLE abs_val(LDOUBLE value)
{
           LDOUBLE result = value;

           if (value < 0)
                         result = -value;
           
           return result;
}

static LDOUBLE POW10(int exp)
{
           LDOUBLE result = 1;
           
           while (exp) {
                         result *= 10;
                         exp--;
           }
  
           return result;
}

static LLONG ROUND(LDOUBLE value)
{
           LLONG intpart;

           intpart = (LLONG)value;
           value = value - intpart;
           if (value >= 0.5) intpart++;
           
           return intpart;
}

/* a replacement for modf that doesn't need the math library. Should
   be portable, but slow */
static double my_modf(double x0, double *iptr)
{
           int i;
           long l;
           double x = x0;
           double f = 1.0;

           for (i=0;i<100;i++) {
                         l = (long)x;
                         if (l <= (x+1) && l >= (x-1)) break;
                         x *= 0.1;
                         f *= 10.0;
           }

           if (i == 100) {
                         /* yikes! the number is beyond what we can handle. What do we do? */
                         (*iptr) = 0;
                         return 0;
           }

           if (i != 0) {
                         double i2;
                         double ret;

                         ret = my_modf(x0-l*f, &i2);
                         (*iptr) = l*f + i2;
                         return ret;
           } 

           (*iptr) = l;
           return x - (*iptr);
}


static void fmtfp (char *buffer, size_t *currlen, size_t maxlen,
                            LDOUBLE fvalue, int min, int max, int flags)
{
           int signvalue = 0;
           double ufvalue;
           char iconvert[311];
           char fconvert[311];
           int iplace = 0;
           int fplace = 0;
           int padlen = 0; /* amount to pad */
           int zpadlen = 0; 
           int caps = 0;
           int index;
           double intpart;
           double fracpart;
           double temp;
  
           /* 
            * AIX manpage says the default is 0, but Solaris says the default
            * is 6, and sprintf on AIX defaults to 6
            */
           if (max < 0)
                         max = 6;

           ufvalue = abs_val (fvalue);

           if (fvalue < 0) {
                         signvalue = '-';
           } else {
                         if (flags & DP_F_PLUS) { /* Do a sign (+/i) */
                                    signvalue = '+';
                         } else {
                                    if (flags & DP_F_SPACE)
                                                  signvalue = ' ';
                         }
           }

#if 0
           if (flags & DP_F_UP) caps = 1; /* Should characters be upper case? */
#endif

#if 0
            if (max == 0) ufvalue += 0.5; /* if max = 0 we must round */
#endif

           /* 
            * Sorry, we only support 16 digits past the decimal because of our 
            * conversion method
            */
           if (max > 16)
                         max = 16;

           /* We "cheat" by converting the fractional part to integer by
            * multiplying by a factor of 10
            */

           temp = ufvalue;
           my_modf(temp, &intpart);

           fracpart = ROUND((POW10(max)) * (ufvalue - intpart));
           
           if (fracpart >= POW10(max)) {
                         intpart++;
                         fracpart -= POW10(max);
           }


           /* Convert integer part */
           do {
                         temp = intpart;
                         my_modf(intpart*0.1, &intpart);
                         temp = temp*0.1;
                         index = (int) ((temp -intpart +0.05)* 10.0);
                         /* index = (int) (((double)(temp*0.1) -intpart +0.05) *10.0); */
                         /* printf ("%llf, %f, %x\n", temp, intpart, index); */
                         iconvert[iplace++] =
                                    (caps? "0123456789ABCDEF":"0123456789abcdef")[index];
           } while (intpart && (iplace < 311));
           if (iplace == 311) iplace--;
           iconvert[iplace] = 0;

           /* Convert fractional part */
           if (fracpart)
           {
                         do {
                                    temp = fracpart;
                                    my_modf(fracpart*0.1, &fracpart);
                                    temp = temp*0.1;
                                    index = (int) ((temp -fracpart +0.05)* 10.0);
                                    /* index = (int) ((((temp/10) -fracpart) +0.05) *10); */
                                    /* printf ("%lf, %lf, %ld\n", temp, fracpart, index); */
                                    fconvert[fplace++] =
                                    (caps? "0123456789ABCDEF":"0123456789abcdef")[index];
                         } while(fracpart && (fplace < 311));
                         if (fplace == 311) fplace--;
           }
           fconvert[fplace] = 0;
  
           /* -1 for decimal point, another -1 if we are printing a sign */
           padlen = min - iplace - max - 1 - ((signvalue) ? 1 : 0); 
           zpadlen = max - fplace;
           if (zpadlen < 0) zpadlen = 0;
           if (padlen < 0) 
                         padlen = 0;
           if (flags & DP_F_MINUS) 
                         padlen = -padlen; /* Left Justifty */
           
           if ((flags & DP_F_ZERO) && (padlen > 0)) {
                         if (signvalue) {
                                    dopr_outch (buffer, currlen, maxlen, signvalue);
                                    --padlen;
                                    signvalue = 0;
                         }
                         while (padlen > 0) {
                                    dopr_outch (buffer, currlen, maxlen, '0');
                                    --padlen;
                         }
           }
           while (padlen > 0) {
                         dopr_outch (buffer, currlen, maxlen, ' ');
                         --padlen;
           }
           if (signvalue) 
                         dopr_outch (buffer, currlen, maxlen, signvalue);
           
           while (iplace > 0) 
                         dopr_outch (buffer, currlen, maxlen, iconvert[--iplace]);

#ifdef DEBUG_SNPRINTF
           printf("fmtfp: fplace=%d zpadlen=%d\n", fplace, zpadlen);
#endif

           /*
            * Decimal point.  This should probably use locale to find the correct
            * char to print out.
            */
           if (max > 0) {
                         dopr_outch (buffer, currlen, maxlen, '.');
                         
                         while (fplace > 0) 
                                    dopr_outch (buffer, currlen, maxlen, fconvert[--fplace]);
           }
           
           while (zpadlen > 0) {
                         dopr_outch (buffer, currlen, maxlen, '0');
                         --zpadlen;
           }

           while (padlen < 0) {
                         dopr_outch (buffer, currlen, maxlen, ' ');
                         ++padlen;
           }
}

static void dopr_outch(char *buffer, size_t *currlen, size_t maxlen, char c)
{
           if (*currlen < maxlen) {
                         buffer[(*currlen)] = c;
           }
           (*currlen)++;
}

int ht_vsnprintf (char *str, size_t count, const char *fmt, va_list args)
{
        if ((int)count < 0) count = 0;
        int res = dopr(str, count, fmt, args);
        if (count) count--;
        return str ? MIN(res, (int)count) : count;
}

int ht_snprintf(char *str, size_t count, const char *fmt,...)
{
        size_t ret;
        va_list ap;

        va_start(ap, fmt);
        ret = ht_vsnprintf(str, count, fmt, ap);
        va_end(ap);
        return ret;
}

int ht_vasprintf(char **ptr, const char *format, va_list ap)
{
        int ret;

        ret = dopr(NULL, 0, format, ap);
        if (ret <= 0) {
                *ptr = NULL;
                return 0;
        }

        (*ptr) = (char *)malloc(ret+1);
        if (!*ptr) return 0;
        ret = ht_vsnprintf(*ptr, ret+1, format, ap);

        return ret;
}


int ht_asprintf(char **ptr, const char *format, ...)
{
        va_list ap;
        int ret;

        va_start(ap, format);
        ret = ht_vasprintf(ptr, format, ap);
        va_end(ap);

        return ret;
}

int ht_vfprintf(FILE *file, const char *fmt, va_list args)
{
#if 0
        char *buf;
        int ret = ht_vasprintf(&buf, fmt, args);
        fputs(buf, file);
        free(buf);
#else
        char buf[1024];
        int ret = ht_vsnprintf(buf, sizeof buf, fmt, args);
        fputs(buf, file);
#endif
        return ret;
}

int ht_fprintf(FILE *file, const char *fmt, ...)
{
        va_list ap;
        int ret;

        va_start(ap, fmt);
        ret = ht_vfprintf(file, fmt, ap);
        va_end(ap);

        return ret;
}


int ht_vprintf(const char *fmt, va_list args)
{
        return ht_vfprintf(stdout, fmt, args);
}

int ht_printf(const char *fmt, ...)
{
        va_list ap;
        int ret;

        va_start(ap, fmt);
        ret = ht_vprintf(fmt, ap);
        va_end(ap);

        return ret;
}

---