dhcp-snprintf.c

this is sample about DHCP-agent

    if(max >= 0 && max < strln)
        strln = max;
    padlen = min - strln;
    if(padlen < 0)
        padlen = 0;
    if(flags & DP_F_MINUS)
        padlen = -padlen; /* Left Justify */

    while(padlen > 0) {
        total += dopr_outch(buffer, currlen, maxlen, ' ');
        --padlen;
    }
    while(*value && ((max < 0) || (cnt < max))) {
        total += dopr_outch(buffer, currlen, maxlen, *value++);
        ++cnt;
    }
    while(padlen < 0) {
        total += dopr_outch(buffer, currlen, maxlen, ' ');
        ++padlen;
    }
    return total;
}

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

static int 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;
    int total = 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) {
        total += dopr_outch(buffer, currlen, maxlen, ' ');
        --spadlen;
    }

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

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

    /* Digits */
    while(place > 0)
        total += dopr_outch(buffer, currlen, maxlen, convert[--place]);

    /* Left Justified spaces */
    while(spadlen < 0) {
        total += dopr_outch(buffer, currlen, maxlen, ' ');
        ++spadlen;
    }

    return total;
}

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 int 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;
    int total = 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) {
            total += dopr_outch(buffer, currlen, maxlen, signvalue);
            --padlen;
            signvalue = 0;
        }
        while(padlen > 0) {
            total += dopr_outch(buffer, currlen, maxlen, '0');
            --padlen;
        }
    }
    while(padlen > 0) {
        total += dopr_outch(buffer, currlen, maxlen, ' ');
        --padlen;
    }
    if(signvalue)
        total += dopr_outch(buffer, currlen, maxlen, signvalue);

    while(iplace > 0)
        total += 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) {
        total += dopr_outch(buffer, currlen, maxlen, '.');

        while(fplace > 0)
            total += dopr_outch(buffer, currlen, maxlen, fconvert[--fplace]);
    }

    while(zpadlen > 0) {
        total += dopr_outch(buffer, currlen, maxlen, '0');
        --zpadlen;
    }

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

    return total;
}

static int dopr_outch(char *buffer, size_t * currlen, size_t maxlen, char c)
{
    if(*currlen + 1 < maxlen)
        buffer[(*currlen)++] = c;
    return 1;
}

#ifndef HAVE_VSNPRINTF
int vsnprintf(char *str, size_t count, const char *fmt, va_list args)
{
    if(str != NULL)
        str[0] = 0;
    return dopr(str, count, fmt, args);
}
#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;
    int total;

    VA_START(fmt);
    VA_SHIFT(str, char *);
    VA_SHIFT(count, size_t);
    VA_SHIFT(fmt, char *);
    total = vsnprintf(str, count, fmt, ap);
    VA_END;
    return total;
}
#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 */