snprintf.c

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/*
 * Copyright Patrick Powell 1995
 * This code is based on code written by Patrick Powell ([e-mail])
 * 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 <[e-mail]> 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 <[e-mail]> 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 <[e-mail]> 01/27/98 for mutt 0.89i
 *    The PGP code was using unsigned hexadecimal formats.
 *    Unfortunately, unsigned formats simply didn't work.
 *
 *  Michael Elkins <[e-mail]> 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 ([e-mail]) Oct 1998
 *    fixed handling of %.0f
 *    added test for HAVE_LONG_DOUBLE
 *
 *  Chris Kirmse ([e-mail]) May 2003
 *    fixed handling of leading zeros in the fractional part of a float.
 *
 **************************************************************/

/* #include "config.h" */
#define HAVE_STDARG_H

/* moved above the #ifdef to avoid warning about empty c-files */
#include <string.h>
#include <ctype.h>
#include <sys/types.h>

#if !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF)


/* Define this as a fall through, HAVE_STDARG_H is probably already set */
#define HAVE_VARARGS_H


/* varargs declarations: */

#if defined(HAVE_STDARG_H)
# include <stdarg.h>
# 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
# if defined(HAVE_VARARGS_H)
#  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)
# else
/*XX ** NO VARARGS ** XX*/
# endif
#endif

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

int snprintf (char *str, size_t count, const char *fmt, ...);
int vsnprintf (char *str, size_t count, const char *fmt, va_list arg);

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,
		    const 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')
#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 (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 (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, (char)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 = (char*)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,
		    const 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 */