/*
 * Replacement for a missing snprintf or vsnprintf.
 *
 * The following implementation of snprintf was taken mostly verbatim from
 * <http://www.fiction.net/blong/programs/>; it is the version of snprintf
 * used in Mutt.  A possibly newer version is used in wget, found at
 * <https://github.com/wertarbyte/wget/blob/master/src/snprintf.c>.
 *
 * Please do not reformat or otherwise change this file more than necessary so
 * that later merges with the original source are easy.  Bug fixes and
 * improvements should be sent back to the original author.
 *
 * The canonical version of this file was maintained (until 2020) in the
 * rra-c-util package, which can be found at
 * <https://www.eyrie.org/~eagle/software/rra-c-util/>.
 */

/*
 * If we're running the test suite, rename snprintf and vsnprintf to avoid
 * conflicts with the system version.
 */
#if TESTING
#    undef snprintf
#    undef vsnprintf
#    define snprintf  test_snprintf
#    define vsnprintf test_vsnprintf
#endif

/*
 * __attribute__ is available in gcc 2.5 and later, but only with gcc 2.7
 * could you use the __format__ form of the attributes, which is what we use
 * (to avoid confusion with other macros).
 */
#ifndef __attribute__
#    if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 7)
#        define __attribute__(spec) /* empty */
#    endif
#endif

/* Specific to rra-c-util, but only when debugging is enabled. */
#ifdef DEBUG_SNPRINTF
#    include "inn/messages.h"
#endif

/*
 * 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
 *
 * There is no SPDX-License-Identifier registered for this license.
 */

/**************************************************************
 * 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, formatted 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
 *
 *  Russ Allbery <eagle@eyrie.org> 2000-08-26
 *    fixed return value to comply with C99
 *    fixed handling of snprintf(NULL, ...)
 *    added explicit casts for double to long long int conversion
 *    fixed various warnings with GCC 7
 *    fixed various warnings with Clang
 *
 *  Hrvoje Niksic <hniksic@xemacs.org> 2000-11-04
 *    include <config.h> instead of "config.h".
 *    moved TEST_SNPRINTF stuff out of HAVE_SNPRINTF ifdef.
 *    include <stdio.h> for NULL.
 *    added support and test cases for long long.
 *    don't declare argument types to (v)snprintf if stdarg is not used.
 *    use int instead of short int as 2nd arg to va_arg.
 *
 *  alexk (INN) 2002-08-21
 *    use LLONG in fmtfp to handle more characters during floating
 *    point conversion.
 *
 *  herb (Samba) 2002-12-19
 *    actually print args for %g and %e
 *
 *  Hrvoje Niksic <hniksic@xemacs.org> 2005-04-15
 *    use the PARAMS macro to handle prototypes.
 *    write function definitions in the ansi2knr-friendly way.
 *    if string precision is specified, don't read VALUE past it.
 *    fix bug in fmtfp that caused 0.01 to be printed as 0.1.
 *    don't include <ctype.h> because none of it is used.
 *    interpret precision as number of significant digits with %g
 *    omit trailing decimal zeros with %g
 *
 **************************************************************/

#include "config.h"

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

#ifndef NULL
#    define NULL 0
#endif

/* varargs declarations: */

#include <stdarg.h>

/* Assume all compilers support long double, per Autoconf documentation. */
#define LDOUBLE long double

#ifdef HAVE_LONG_LONG_INT
#    define LLONG long long
#else
#    define LLONG long
#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,
                  const char *value, int flags, int min, int max);
static int fmtint(char *buffer, size_t *currlen, size_t maxlen, LLONG 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_MOD_L     6
#define DP_S_CONV      7
#define DP_S_DONE      8

/* 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)
#define DP_F_FP_G      (1 << 7)

/* Conversion Flags */
#define DP_C_SHORT     1
#define DP_C_LONG      2
#define DP_C_LLONG     3
#define DP_C_LDOUBLE   4

#define char_to_int(p) (p - '0')
#define MAX(p, q)      ((p >= q) ? p : q)

static int
dopr(char *buffer, size_t maxlen, const char *format, va_list args)
{
    char ch;
    LLONG value;
    LDOUBLE fvalue;
    char *strvalue;
    int min;
    int max;
    unsigned 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 ('0' <= ch && ch <= '9') {
                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 ('0' <= ch && ch <= '9') {
                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:
            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;
            }
            if (cflags != DP_C_LONG)
                state = DP_S_CONV;
            else
                state = DP_S_MOD_L;
            break;
        case DP_S_MOD_L:
            switch (ch) {
            case 'l':
                cflags = DP_C_LLONG;
                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 = (short int) va_arg(args, int);
                else if (cflags == DP_C_LONG)
                    value = va_arg(args, long int);
                else if (cflags == DP_C_LLONG)
                    value = va_arg(args, LLONG);
                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 = (unsigned short int) va_arg(args, unsigned int);
                else if (cflags == DP_C_LONG)
                    value = va_arg(args, unsigned long int);
                else if (cflags == DP_C_LLONG)
                    value = va_arg(args, unsigned LLONG);
                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 = (unsigned short int) va_arg(args, unsigned int);
                else if (cflags == DP_C_LONG)
                    value = va_arg(args, unsigned long int);
                else if (cflags == DP_C_LLONG)
                    value = va_arg(args, unsigned LLONG);
                else
                    value = va_arg(args, unsigned int);
                total += fmtint(buffer, &currlen, maxlen, value, 10, min, max,
                                flags);
                break;
            case 'X':
                flags |= DP_F_UP;
                goto fallthrough1;
            case 'x':
            fallthrough1:
                flags |= DP_F_UNSIGNED;
                if (cflags == DP_C_SHORT)
                    value = (unsigned short int) va_arg(args, unsigned int);
                else if (cflags == DP_C_LONG)
                    value = va_arg(args, unsigned long int);
                else if (cflags == DP_C_LLONG)
                    value = va_arg(args, unsigned LLONG);
                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 = (LDOUBLE) va_arg(args, double);
                total +=
                    fmtfp(buffer, &currlen, maxlen, fvalue, min, max, flags);
                break;
            case 'E':
                flags |= DP_F_UP;
                goto fallthrough2;
            case 'e':
            fallthrough2:
                if (cflags == DP_C_LDOUBLE)
                    fvalue = va_arg(args, LDOUBLE);
                else
                    fvalue = (LDOUBLE) va_arg(args, double);
                total +=
                    fmtfp(buffer, &currlen, maxlen, fvalue, min, max, flags);
                break;
            case 'G':
                flags |= DP_F_UP;
                goto fallthrough3;
            case 'g':
            fallthrough3:
                flags |= DP_F_FP_G;
                if (cflags == DP_C_LDOUBLE)
                    fvalue = va_arg(args, LDOUBLE);
                else
                    fvalue = (LDOUBLE) va_arg(args, double);
                if (max == 0)
                    /* C99 says: if precision [for %g] is zero, it is taken as
                     * one */
                    max = 1;
                total +=
                    fmtfp(buffer, &currlen, maxlen, fvalue, min, max, flags);
                break;
            case 'c':
                total += dopr_outch(buffer, &currlen, maxlen,
                                    (char) 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 = (short) currlen;
                } else if (cflags == DP_C_LONG) {
                    long int *num;
                    num = va_arg(args, long int *);
                    *num = currlen;
                } else if (cflags == DP_C_LLONG) {
                    LLONG *num;
                    num = va_arg(args, LLONG *);
                    *num = currlen;
                } else {
                    int *num;
                    num = va_arg(args, int *);
                    *num = (int) currlen;
                }
                break;
            case '%':
                total += dopr_outch(buffer, &currlen, maxlen, ch);
                break;
            case 'w':
                /* not supported yet, treat as next char */
                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, const 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)";
    }

    if (max < 0)
        strln = (int) strlen(value);
    else
        /* When precision is specified, don't read VALUE past precision. */
        /*strln = strnlen (value, max);*/
        for (strln = 0; strln < max && value[strln]; ++strln)
            ;
    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, LLONG value, int base,
       int min, int max, int flags)
{
    char signvalue = 0;
    unsigned LLONG uvalue;
    char convert[24];
    unsigned int place = 0;
    int spadlen = 0; /* amount to space pad */
    int zpadlen = 0; /* amount to zero pad */
    const char *digits;
    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)
        /* Should characters be upper case? */
        digits = "0123456789ABCDEF";
    else
        digits = "0123456789abcdef";

    do {
        convert[place++] = digits[uvalue % (unsigned) base];
        uvalue = (uvalue / (unsigned) base);
    } while (uvalue && (place < sizeof(convert)));
    if (place == sizeof(convert))
        place--;
    convert[place] = 0;

    zpadlen = max - place;
    spadlen = min - MAX((unsigned int) 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
    debug("zpad: %d, spad: %d, min: %d, max: %d, place: %u\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 LLONG
pow10_int(unsigned int exp)
{
    LDOUBLE result = 1;

    while (exp) {
        result *= 10;
        exp--;
    }

    return (LLONG) result;
}

static LLONG
round_int(LDOUBLE value)
{
    LLONG intpart;

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

    return intpart;
}

/*
 * GCC 7.1 issues this warning at the point of the function definition header
 * (not in any actual code), and I can't figure out what's triggering it since
 * the comparison form doesn't appear anywhere in this code.  Since this is
 * rarely-used portability code, suppress the warning.
 */
#pragma GCC diagnostic ignored "-Wstrict-overflow"

static int
fmtfp(char *buffer, size_t *currlen, size_t maxlen, LDOUBLE fvalue, int min,
      int max, int flags)
{
    char signvalue = 0;
    LDOUBLE ufvalue;
    char iconvert[24];
    char fconvert[24];
    size_t iplace = 0;
    size_t fplace = 0;
    long padlen = 0; /* amount to pad */
    long zpadlen = 0;
    int total = 0;
    LLONG intpart;
    LLONG fracpart;
    LLONG mask10;
    int leadingfrac0s = 0; /* zeroes at the start of fractional part */
    int omitzeros = 0;
    size_t omitcount = 0;

    /*
     * 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 = (LLONG) ufvalue;

    /* With %g precision is the number of significant digits, which
       includes the digits in intpart. */
    if (flags & DP_F_FP_G) {
        if (intpart != 0) {
            /* For each digit of INTPART, print one less fractional digit. */
            LLONG temp;
            for (temp = intpart; temp != 0; temp /= 10)
                --max;
            if (max < 0)
                max = 0;
        } else {
            /* For each leading 0 in fractional part, print one more
               fractional digit. */
            LDOUBLE temp;
            if (ufvalue > 0)
                for (temp = ufvalue; temp < (LDOUBLE) 0.1; temp *= 10)
                    ++max;
        }
    }

    /* C99: trailing zeros are removed from the fractional portion of the
       result unless the # flag is specified */
    if ((flags & DP_F_FP_G) && !(flags & DP_F_NUM))
        omitzeros = 1;

#if SIZEOF_LONG_LONG > 0
#    define MAX_DIGITS 18 /* grok more digits with long long */
#else
#    define MAX_DIGITS 9 /* just long */
#endif

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

    /* Factor of 10 with the needed number of digits, e.g. 1000 for max==3 */
    mask10 = pow10_int(max);

    /* We "cheat" by converting the fractional part to integer by
     * multiplying by a factor of 10
     */
    fracpart = round_int(mask10 * (ufvalue - intpart));

    if (fracpart >= mask10) {
        intpart++;
        fracpart -= mask10;
    } else if (fracpart != 0)
        /* If fracpart has less digits than the 10* mask, we need to
           manually insert leading 0s.  For example 2.01's fractional part
           requires one leading zero to distinguish it from 2.1. */
        while (fracpart < mask10 / 10) {
            ++leadingfrac0s;
            mask10 /= 10;
        }

#ifdef DEBUG_SNPRINTF
#    ifdef HAVE_LONG_LONG_INT
    debug("fmtfp: %Lf =? %lld.%lld\n", fvalue, intpart, fracpart);
#    else
    debug("fmtfp: %Lf =? %ld.%ld\n", fvalue, intpart, fracpart);
#    endif
#endif

    /* Convert integer part */
    do {
        iconvert[iplace++] = (char) ('0' + (intpart % 10));
        intpart = (intpart / 10);
    } while (intpart && (iplace < sizeof(iconvert)));
    if (iplace == sizeof(iconvert))
        iplace--;
    iconvert[iplace] = 0;

    /* Convert fractional part */
    do {
        fconvert[fplace++] = (char) ('0' + (fracpart % 10));
        fracpart = (fracpart / 10);
    } while (fracpart && (fplace < sizeof(fconvert)));
    while (leadingfrac0s-- > 0 && fplace < sizeof(fconvert))
        fconvert[fplace++] = '0';
    if (fplace == sizeof(fconvert))
        fplace--;
    fconvert[fplace] = 0;
    if (omitzeros)
        while (omitcount < fplace && fconvert[omitcount] == '0')
            ++omitcount;

    /* -1 for decimal point, another -1 if we are printing a sign */
    padlen = min - iplace - (max - omitcount) - 1 - ((signvalue) ? 1 : 0);
    if (!omitzeros)
        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 && (fplace > omitcount || zpadlen > 0)) {
        total += dopr_outch(buffer, currlen, maxlen, '.');

        while (fplace > omitcount)
            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;
}

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);
}

int
snprintf(char *str, size_t count, const char *fmt, ...)
{
    va_list ap;
    int total;

    va_start(ap, fmt);
    total = vsnprintf(str, count, fmt, ap);
    va_end(ap);
    return total;
}

#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);
    return 0;
}
#endif /* TEST_SNPRINTF */
