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.
 *
 *  Ben Lindstrom <mouring@eviladmin.org> 09/27/00 for OpenSSH
 *    Welcome to the world of %lld and %qd support.  With other
 *    long long support.  This is needed for sftp-server to work
 *    right.
 *
 *  Ben Lindstrom <mouring@eviladmin.org> 02/12/01 for OpenSSH
 *    Removed all hint of VARARGS stuff and banished it to the void,
 *    and did a bit of KNF style work to make things a bit more
 *    acceptable.  Consider stealing from mutt or enlightenment.
 **************************************************************/

#if HAVE_CONFIG_H
#include "config.h"
#endif

#if defined(BROKEN_SNPRINTF)        /* For those with broken snprintf() */
# undef HAVE_SNPRINTF
# undef HAVE_VSNPRINTF
#endif

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

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

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, long double 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 DP_C_LONG_LONG 4

#define char_to_int(p) (p - '0')
#define abs_val(p) (p < 0 ? -p : p)

#ifndef MAX
#define MAX(a, b) ((a > b) ? a : b)
#endif

static void
dopr(char *buffer, size_t maxlen, const char *format, va_list args) {
    char *strvalue, ch;
    long value;
    long double fvalue;
    int min = 0, max = -1, state = DP_S_DEFAULT, flags = 0, cflags = 0;
    size_t currlen = 0;

    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((unsigned char) 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((unsigned char) 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:
                switch (ch) {
                    case 'h':
                        cflags = DP_C_SHORT;
                        ch = *format++;
                        break;
                    case 'l':
                        cflags = DP_C_LONG;
                        ch = *format++;
                        if (ch == 'l') {
                            cflags = DP_C_LONG_LONG;
                            ch = *format++;
                        }
                        break;
                    case 'q':
                        cflags = DP_C_LONG_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 if (cflags == DP_C_LONG_LONG)
                            value = va_arg (args, long
                                    long);
                        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
                                    int);
                        else if (cflags == DP_C_LONG)
                            value = va_arg(args, unsigned
                                    long
                                    int);
                        else if (cflags == DP_C_LONG_LONG)
                            value = va_arg(args, unsigned
                                    long
                                    long);
                        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
                                    int);
                        else if (cflags == DP_C_LONG)
                            value = va_arg(args, unsigned
                                    long
                                    int);
                        else if (cflags == DP_C_LONG_LONG)
                            value = va_arg(args, unsigned
                                    long
                                    long);
                        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
                                    int);
                        else if (cflags == DP_C_LONG)
                            value = va_arg(args, unsigned
                                    long
                                    int);
                        else if (cflags == DP_C_LONG_LONG)
                            value = va_arg(args, unsigned
                                    long
                                    long);
                        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, long
                                    double);
                        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, long
                                    double);
                        else
                            fvalue = va_arg(args, double);
                        break;
                    case 'G':
                        flags |= DP_F_UP;
                    case 'g':
                        if (cflags == DP_C_LDOUBLE)
                            fvalue = va_arg(args, long
                                    double);
                        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 = 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 if (cflags == DP_C_LONG_LONG) {
                            long long *num;
                            num = va_arg(args, long long *);
                            *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 cnt = 0, padlen, strln;     /* amount to pad */

    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) {
    unsigned long uvalue;
    char convert[20];
    int signvalue = 0, place = 0, caps = 0;
    int spadlen = 0; /* amount to space pad */
    int zpadlen = 0; /* amount to zero pad */

    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 */

    /* 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 long double
pow10(int exp) {
    long double result = 1;

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

    return result;
}

static long
round(long double value) {
    long intpart = value;

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

    return intpart;
}

static void
fmtfp(char *buffer, size_t *currlen, size_t maxlen, long double fvalue,
      int min, int max, int flags) {
    char iconvert[20], fconvert[20];
    int signvalue = 0, iplace = 0, fplace = 0;
    int padlen = 0; /* amount to pad */
    int zpadlen = 0, caps = 0;
    long intpart, fracpart;
    long double ufvalue;

    /*
     * 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 = ' ';

    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);
    }

    /* 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.
     */
    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;
}

#endif /* !defined(HAVE_SNPRINTF) || !defined(HAVE_VSNPRINTF) */

#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

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

    va_start(ap, fmt);
    (void) vsnprintf(str, count, fmt, ap);
    va_end(ap);

    return (strlen(str));
}

#endif /* !HAVE_SNPRINTF */