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snprintf.c

/*
 * snprintf.c - a portable implementation of snprintf and vsnprintf
 *
 * $Id: snprintf.c,v 1.20 2004/01/13 10:21:00 wcc Exp $
 */
/*
 * Portions Copyright (C) 2000, 2001, 2002, 2003, 2004 Eggheads Development Team
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include "main.h"
#include "snprintf.h"


/*
 * 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
 *
 *  Fabian Knittel <fknittel@gmx.de> Apr 2000 for eggdrop 1.5.3
 *    Indented code to match eggdrop style. Adjusted to fit into eggdrops
 *    build environment. Added `egg_' prefixes to snprintf and vsnprintf.
 *
 **************************************************************/

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

#ifndef HAVE_VSNPRINTF

/* varargs declarations: */

#if defined(__STDC__)
#  ifdef HAVE_STDARG_H
#    include <stdarg.h>
#  else
#    ifdef HAVE_STD_ARGS_H
#      include <std_args.h>
#    endif
#  endif
#  define HAVE_STDARGS          /* let's hope that works everywhere (mj) */
#  define VA_LOCAL_DECL va_list ap
#  define VA_START(f)   va_start(ap, f)
#  define VA_SHIFT(v,t) ;       /* no-op for ANSI */
#  define VA_END        va_end(ap)
#else
#  include <varargs.h>
#  undef HAVE_STDARGS
#  define VA_LOCAL_DECL va_list ap
#  define VA_START(f)   va_start(ap)    /* f is ignored! */
#  define VA_SHIFT(v,t) v = va_arg(ap,t)
#  define VA_END        va_end(ap)
#endif

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

static void 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 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 char_to_int(p) (p - '0')

#ifdef MAX
#  undef MAX
#endif
#define MAX(p,q) ((p >= q) ? p : q)

static void dopr(char *buffer, size_t maxlen, const char *format, va_list args)
{
  char ch;
  long 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') || (currlen >= maxlen))
      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 (egg_isdigit(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 (egg_isdigit(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:
      /* Currently, we don't support Long Long, bummer */
      switch (ch) {
      case 'h':
        cflags = DP_C_SHORT;
        ch = *format++;
        break;
      case 'l':
        cflags = DP_C_LONG;
        ch = *format++;
        break;
      case 'L':
        cflags = DP_C_LDOUBLE;
        ch = *format++;
        break;
      default:
        break;
      }
      state = DP_S_CONV;
      break;
    case DP_S_CONV:
      switch (ch) {
      case 'd':
      case 'i':
        if (cflags == DP_C_SHORT)
          value = va_arg(args, short int);

        else if (cflags == DP_C_LONG)
          value = va_arg(args, long int);

        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 short int);

        else if (cflags == DP_C_LONG)
          value = va_arg(args, unsigned long int);

        else
          value = 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 short int);

        else if (cflags == DP_C_LONG)
          value = va_arg(args, unsigned long int);

        else
          value = 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 short int);

        else if (cflags == DP_C_LONG)
          value = va_arg(args, unsigned long int);

        else
          value = 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 (max < 0)
          max = maxlen;         /* ie, no max */
        fmtstr(buffer, &currlen, maxlen, strvalue, flags, min, max);
        break;
      case 'p':
        strvalue = va_arg(args, void *);

        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 = 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;
      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 (currlen < maxlen - 1)
    buffer[currlen] = '\0';
  else
    buffer[maxlen - 1] = '\0';
}

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;

  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)
{
  int signvalue = 0;
  unsigned long uvalue;
  char convert[20];
  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 < 20));
  if (place == 20)
    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
  dprint(1,
         (debugfile, "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 long round(LDOUBLE value)
{
  long intpart;

  intpart = value;
  value = value - intpart;
  if (value >= 0.5)
    intpart++;

  return intpart;
}

static void fmtfp(char *buffer, size_t *currlen, size_t maxlen,
                  LDOUBLE fvalue, int min, int max, int flags)
{
  int signvalue = 0;
  LDOUBLE ufvalue;
  char iconvert[20];
  char fconvert[20];
  int iplace = 0;
  int fplace = 0;
  int padlen = 0;               /* amount to pad */
  int zpadlen = 0;
  int caps = 0;
  long intpart;
  long fracpart;

  /*
   * 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

  intpart = ufvalue;

  /*
   * Sorry, we only support 9 digits past the decimal because of our
   * conversion method
   */
  if (max > 9)
    max = 9;

  /* We "cheat" by converting the fractional part to integer by
   * multiplying by a factor of 10
   */
  fracpart = round((pow10(max)) * (ufvalue - intpart));

  if (fracpart >= pow10(max)) {
    intpart++;
    fracpart -= pow10(max);
  }

  /* Convert integer part */
  do {
    iconvert[iplace++] =
      (caps ? "0123456789ABCDEF" : "0123456789abcdef")[intpart % 10];
    intpart = (intpart / 10);
  }
  while (intpart && (iplace < 20));
  if (iplace == 20)
    iplace--;
  iconvert[iplace] = 0;

  /* Convert fractional part */
  do {
    fconvert[fplace++] =
      (caps ? "0123456789ABCDEF" : "0123456789abcdef")[fracpart % 10];
    fracpart = (fracpart / 10);
  }
  while (fracpart && (fplace < 20));
  if (fplace == 20)
    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]);

  /*
   * 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;
}

int egg_vsnprintf(char *str, size_t count, const char *fmt, va_list args)
{
  str[0] = 0;
  dopr(str, count, fmt, args);
  return (strlen(str));
}
#endif /* !HAVE_VSNPRINTF */

#ifndef HAVE_SNPRINTF
#  ifdef HAVE_STDARGS
int egg_snprintf(char *str, size_t count, const char *fmt, ...)
#  else
int egg_snprintf(va_alist)
va_dcl
#  endif
{
#  ifndef HAVE_STDARGS
  char *str;
  size_t count;
  char *fmt;
#  endif
  VA_LOCAL_DECL;

  VA_START(fmt);
  VA_SHIFT(str, char *);

  VA_SHIFT(count, size_t);
  VA_SHIFT(fmt, char *);

  (void) egg_vsnprintf(str, count, fmt, ap);
  VA_END;
  return (strlen(str));
}
#endif /* !HAVE_SNPRINTF */

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