dhcp-snprintf.c

this is sample about DHCP-agent

/*
 * 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
 */

/*********************************************************
 * Taken from the mutt project.
 * Recent changes:
 *
 * Thamer Alharbash <[e-mail]>, June, 2003:
 *
 * Some minor tweaks to keep it healthy on newer gcc, and
 * platforms like Solaris. 
 * 
 *********************************************************/

/**************************************************************
 * 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
 *
 *  Russ Allbery <[e-mail]> 2000-08-26
 *    fixed return value to comply with C99
 *    fixed handling of snprintf(NULL, ...)
 *
 **************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif                          /* HAVE_CONFIG_H */

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

#include <string.h>
#include <ctype.h>
#include <sys/types.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 int dopr(char *buffer, size_t maxlen, const char *format, va_list args);
static int fmtstr(char *buffer, size_t * currlen, size_t maxlen,
                  char *value, int flags, int min, int max);
static int fmtint(char *buffer, size_t * currlen, size_t maxlen,
                  long value, int base, int min, int max, int flags);
static int fmtfp(char *buffer, size_t * currlen, size_t maxlen,
                 LDOUBLE fvalue, int min, int max, int flags);
static int 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)
#define MIN(p,q) ((p <= q) ? p : q)

static int 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;
    int total;
    size_t currlen;

    state = DP_S_DEFAULT;
    currlen = flags = cflags = min = 0;
    max = -1;
    ch = *format++;
    total = 0;

    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
                total += 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((int)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((int)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, int);
                else if(cflags == DP_C_LONG)
                    value = va_arg(args, long int);
                else
                    value = va_arg(args, int);
                total += 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 = va_arg(args, unsigned long int);
                else
                    value = va_arg(args, unsigned int);
                total += 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 = va_arg(args, unsigned long int);
                else
                    value = va_arg(args, unsigned int);
                total += 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 = va_arg(args, unsigned long int);
                else
                    value = va_arg(args, unsigned int);
                total += 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? */
                total += 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':
                total += dopr_outch(buffer, &currlen, maxlen, va_arg(args, int));
                break;
            case 's':
                strvalue = va_arg(args, char *);
                total += fmtstr(buffer, &currlen, maxlen, strvalue, flags, min, max);
                break;
            case 'p':
                strvalue = va_arg(args, void *);
                total += 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 '%':
                total += 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(buffer != NULL) {
        if(currlen < maxlen - 1)
            buffer[currlen] = '\0';
        else
            buffer[maxlen - 1] = '\0';
    }
    return total;
}

static int 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;
    int total = 0;

    if(value == 0) {
        value = "<NULL>";
    }

    for(strln = 0; value[strln]; ++strln); /* strlen */