snprintf.c

/*
 * 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
 *
 **************************************************************/

#include <net-snmp/net-snmp-config.h>

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

#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#include <ctype.h>
#include <sys/types.h>

#if 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)
#elif 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

#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,
                       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, 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,
       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);
    }
#ifdef DEBUG_SNPRINTF
    dprint(1,
           (debugfile, "fmtfp: %f =? %d.%d\n", fvalue, intpart, fracpart));
#endif

    /*
     * 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;
}

#ifndef HAVE_VSNPRINTF
int
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
/*
 * VARARGS3 
 */
#ifdef HAVE_STDARGS
int
snprintf(char *str, size_t count, const char *fmt, ...)
#else
int
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) vsnprintf(str, count, fmt, ap);
    VA_END;
    return (strlen(str));
}
#endif                          /* !HAVE_SNPRINTF */

#ifdef TEST_SNPRINTF
#ifndef LONG_STRING
#define LONG_STRING 1024
#endif
int
main(void)
{
    char            buf1[LONG_STRING];
    char            buf2[LONG_STRING];
    char           *fp_fmt[] = {
        "%-1.5f",
        "%1.5f",
        "%123.9f",
        "%10.5f",
        "% 10.5f",
        "%+22.9f",
        "%+4.9f",
        "%01.3f",
        "%4f",
        "%3.1f",
        "%3.2f",
        "%.0f",
        "%.1f",
        NULL
    };
    double          fp_nums[] =
        { -1.5, 134.21, 91340.2, 341.1234, 0203.9, 0.96, 0.996,
        0.9996, 1.996, 4.136, 0
    };
    char           *int_fmt[] = {
        "%-1.5d",
        "%1.5d",
        "%123.9d",
        "%5.5d",
        "%10.5d",
        "% 10.5d",
        "%+22.33d",
        "%01.3d",
        "%4d",
        NULL
    };
    long            int_nums[] = { -1, 134, 91340, 341, 0203, 0 };
    int             x, y;
    int             fail = 0;
    int             num = 0;

    printf("Testing snprintf format codes against system sprintf...\n");

    for (x = 0; fp_fmt[x] != NULL; x++)
        for (y = 0; fp_nums[y] != 0; y++) {
            snprintf(buf1, sizeof(buf1), fp_fmt[x], fp_nums[y]);
            sprintf(buf2, fp_fmt[x], fp_nums[y]);
            if (strcmp(buf1, buf2)) {
                printf
                    ("snprintf doesn't match Format: %s\n\tsnprintf = %s\n\tsprintf  = %s\n",
                     fp_fmt[x], buf1, buf2);
                fail++;
            }
            num++;
        }

    for (x = 0; int_fmt[x] != NULL; x++)
        for (y = 0; int_nums[y] != 0; y++) {
            snprintf(buf1, sizeof(buf1), int_fmt[x], int_nums[y]);
            sprintf(buf2, int_fmt[x], int_nums[y]);
            if (strcmp(buf1, buf2)) {
                printf
                    ("snprintf doesn't match Format: %s\n\tsnprintf = %s\n\tsprintf  = %s\n",
                     int_fmt[x], buf1, buf2);
                fail++;
            }
            num++;
        }
    printf("%d tests failed out of %d.\n", fail, num);
}
#endif                          /* SNPRINTF_TEST */

#endif                          /* !HAVE_SNPRINTF */

---