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snprintf.c

/*
 * snprintf.c - a portable implementation of snprintf and vsnprintf
 *
 * $Id: snprintf.c,v 1.5 2004/01/26 16:18:23 we7u Exp $
 */
/*
 * Portions Copyright (C) 2000-2004 The Xastir Group
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */


#include "snprintf.h"
#include "config.h"

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

#ifndef HAVE_VSNPRINTF

/* varargs declarations: */

#if defined(__STDC__)
#  ifdef HAVE_STDARG_H
#    include <stdarg.h>
#  else // HAVE_STDARG_H
#    ifdef HAVE_STD_ARGS_H
#      include <std_args.h>
#    endif  // HAVE_STD_ARGS_H
#  endif    // 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   // __STDC__
#  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)
#endif  // __STDC__

#ifdef HAVE_LONG_DOUBLE
#define LDOUBLE long double
#else   // HAVE_LONG_DOUBLE
#define LDOUBLE double
#endif  // HAVE_LONG_DOUBLE

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 = 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  // DEBUG_SNPRINTF

    /* 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  // 0

    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.
    */
    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;
}

int xastir_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
#  ifdef HAVE_STDARGS
int xastir_snprintf(char *str, size_t count, const char *fmt, ...)
#  else // HAVE_STDARGS
int xastir_snprintf(va_alist) va_dcl
#  endif    // HAVE_STDARGS
{
#  ifndef HAVE_STDARGS
    char *str;
    size_t count;
    char *fmt;
#  endif    // HAVE_STDARGS
    VA_LOCAL_DECL;

    VA_START(fmt);
    VA_SHIFT(str, char *);
    VA_SHIFT(count, size_t);
    VA_SHIFT(fmt, char *);
    (void) xastir_vsnprintf(str, count, fmt, ap);
    VA_END;
    return (strlen(str));
}
#endif /* !HAVE_SNPRINTF */



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