vsnprintf.c

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/*-
 * Copyright (c) 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * IMPORTANT NOTE:
 * --------------
 * From ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change
 * paragraph 3 above is now null and void.
 */

/* SNPRINTF.C
 * fjc 7-31-97 Modified by Mib Software to be a standalone snprintf.c module.
 *      http://www.mibsoftware.com
 * Mib Software does not warrant this software any differently than the
 * University of California, Berkeley as described above.  All warranties
 * are disclaimed.  Use this software at your own risk.
 *
 *      All code referencing FILE * functions was eliminated, since it could
 *      never be called.  All header files and necessary files are collapsed
 *      into one file, internal functions are declared static.  This should
 *      allow inclusion into libraries with less chance of namespace collisions.
 *
 *      snprintf should be the only externally visible item.
 *
 *      As of 7-31-97 FLOATING_POINT is NOT provided.  The code is somewhat
 *        non-portable, so it is disabled.
 */

/* Define FLOATING_POINT to get floating point. */
/*
#define FLOATING_POINT
*/

#include <sys/types.h>
#define u_long unsigned long
#define u_short unsigned short
#define u_int unsigned int

#if !defined(HAVE_STDARG_PROTOTYPES)
#if defined(__STDC__)
#define HAVE_STDARG_PROTOTYPES 1
#endif
#endif

#undef __P
#if defined(HAVE_STDARG_PROTOTYPES)
# include <stdarg.h>
# if !defined(__P)
#  define __P(x) x
# endif
#else
# define __P(x) ()
# if !defined(const)
#  define const
# endif
# include <varargs.h>
#endif
#ifndef _BSD_VA_LIST_
#define _BSD_VA_LIST_ va_list
#endif

#ifdef __STDC__
# include <limits.h>
#else
# ifndef LONG_MAX
#  ifdef HAVE_LIMITS_H
#   include <limits.h>
#  else
    /* assuming 32bit(2's compliment) long */
#   define LONG_MAX 2147483647
#  endif
# endif
#endif

#if defined(__hpux) && !defined(__GNUC__) && !defined(__STDC__)
#define const
#endif

#if defined(sgi)
#undef __const
#define __const
#endif /* People who don't like const sys_error */

#include <stddef.h>
#if defined(__hpux) && !defined(__GNUC__) || defined(__DECC)
#include <string.h>
#endif

#if !defined(__CYGWIN32__) && defined(__hpux) && !defined(__GNUC__)
#include <stdlib.h>
#endif

#ifndef NULL
#define NULL    0
#endif

#if SIZEOF_LONG > SIZEOF_INT
# include <errno.h>
#endif

/*
 * NB: to fit things in six character monocase externals, the stdio
 * code uses the prefix `__s' for stdio objects, typically followed
 * by a three-character attempt at a mnemonic.
 */

/* stdio buffers */
struct __sbuf {
        unsigned char *_base;
        size_t  _size;
};


/*
 * stdio state variables.
 *
 * The following always hold:
 *
 *      if (_flags&(__SLBF|__SWR)) == (__SLBF|__SWR),
 *              _lbfsize is -_bf._size, else _lbfsize is 0
 *      if _flags&__SRD, _w is 0
 *      if _flags&__SWR, _r is 0
 *
 * This ensures that the getc and putc macros (or inline functions) never
 * try to write or read from a file that is in `read' or `write' mode.
 * (Moreover, they can, and do, automatically switch from read mode to
 * write mode, and back, on "r+" and "w+" files.)
 *
 * _lbfsize is used only to make the inline line-buffered output stream
 * code as compact as possible.
 *
 * _ub, _up, and _ur are used when ungetc() pushes back more characters
 * than fit in the current _bf, or when ungetc() pushes back a character
 * that does not match the previous one in _bf.  When this happens,
 * _ub._base becomes non-nil (i.e., a stream has ungetc() data iff
 * _ub._base!=NULL) and _up and _ur save the current values of _p and _r.
 *
 * NB: see WARNING above before changing the layout of this structure!
 */
typedef struct __sFILE {
        unsigned char *_p;      /* current position in (some) buffer */
#if 0
        size_t  _r;             /* read space left for getc() */
#endif
        size_t  _w;             /* write space left for putc() */
        short   _flags;         /* flags, below; this FILE is free if 0 */
        short   _file;          /* fileno, if Unix descriptor, else -1 */
        struct  __sbuf _bf;     /* the buffer (at least 1 byte, if !NULL) */
        size_t  _lbfsize;       /* 0 or -_bf._size, for inline putc */
        int     (*vwrite)(/* struct __sFILE*, struct __suio * */);
} FILE;


#define __SLBF  0x0001          /* line buffered */
#define __SNBF  0x0002          /* unbuffered */
#define __SRD   0x0004          /* OK to read */
#define __SWR   0x0008          /* OK to write */
        /* RD and WR are never simultaneously asserted */
#define __SRW   0x0010          /* open for reading & writing */
#define __SEOF  0x0020          /* found EOF */
#define __SERR  0x0040          /* found error */
#define __SMBF  0x0080          /* _buf is from malloc */
#define __SAPP  0x0100          /* fdopen()ed in append mode */
#define __SSTR  0x0200          /* this is an sprintf/snprintf string */
#define __SOPT  0x0400          /* do fseek() optimisation */
#define __SNPT  0x0800          /* do not do fseek() optimisation */
#define __SOFF  0x1000          /* set iff _offset is in fact correct */
#define __SMOD  0x2000          /* true => fgetln modified _p text */


#define EOF     (-1)


#define __sfeof(p)      (((p)->_flags & __SEOF) != 0)
#define __sferror(p)    (((p)->_flags & __SERR) != 0)
#define __sclearerr(p)  ((void)((p)->_flags &= ~(__SERR|__SEOF)))
#define __sfileno(p)    ((p)->_file)

#undef feof
#undef ferror
#undef clearerr
#define feof(p)         __sfeof(p)
#define ferror(p)       __sferror(p)
#define clearerr(p)     __sclearerr(p)

#ifndef _ANSI_SOURCE
#define fileno(p)       __sfileno(p)
#endif


/*
 * I/O descriptors for __sfvwrite().
 */
struct __siov {
        const void *iov_base;
        size_t  iov_len;
};
struct __suio {
        struct  __siov *uio_iov;
        int     uio_iovcnt;
        size_t  uio_resid;
};

/*
 * Write some memory regions.  Return zero on success, EOF on error.
 *
 * This routine is large and unsightly, but most of the ugliness due
 * to the three different kinds of output buffering is handled here.
 */
static int BSD__sfvwrite(fp, uio)
        register FILE *fp;
        register struct __suio *uio;
{
        register size_t len;
        register const char *p;
        register struct __siov *iov;
        register size_t w;

        if ((len = uio->uio_resid) == 0)
                return (0);
#ifndef __hpux
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#endif
#define COPY(n)   (void)memcpy((void *)fp->_p, (void *)p, (size_t)(n))

        iov = uio->uio_iov;
        p = iov->iov_base;
        len = iov->iov_len;
        iov++;
#define GETIOV(extra_work) \
        while (len == 0) { \
                extra_work; \
                p = iov->iov_base; \
                len = iov->iov_len; \
                iov++; \
        }
        if (fp->_flags & __SNBF) {
        /* fjc 7-31-97 Will never happen.  We are working with
                                           strings only
        */
        } else if ((fp->_flags & __SLBF) == 0) {
        /*
                 * Fully buffered: fill partially full buffer, if any,
                 * and then flush.  If there is no partial buffer, write
                 * one _bf._size byte chunk directly (without copying).
                 *
                 * String output is a special case: write as many bytes
                 * as fit, but pretend we wrote everything.  This makes
                 * snprintf() return the number of bytes needed, rather
                 * than the number used, and avoids its write function
                 * (so that the write function can be invalid).
                 */
                do {
                        GETIOV(;);
                        w = fp->_w;
                        if (fp->_flags & __SSTR) {
                                if (len < w)
                                        w = len;
                                COPY(w);        /* copy MIN(fp->_w,len), */
                                fp->_w -= w;
                                fp->_p += w;
                                w = len;        /* but pretend copied all */
                        } else {
                                /* fjc 7-31-97 Will never happen.  We are working with
                                                                   strings only
                                */
                        }
                        p += w;
                        len -= w;
                } while ((uio->uio_resid -= w) != 0);
        } else {
                /* fjc 7-31-97 Will never happen.  We are working with
                                                   strings only
                */
        }
        return (0);
}

/*
 * Actual printf innards.
 *
 * This code is large and complicated...
 */

/*
 * Flush out all the vectors defined by the given uio,
 * then reset it so that it can be reused.
 */
static int
BSD__sprint(FILE *fp, register struct __suio *uio)
{
        register int err;

        if (uio->uio_resid == 0) {
                uio->uio_iovcnt = 0;
                return (0);
        }
        err = (*fp->vwrite)(fp, uio);
        uio->uio_resid = 0;
        uio->uio_iovcnt = 0;
        return (err);
}


/*
 * Helper function for `fprintf to unbuffered unix file': creates a
 * temporary buffer.  We only work on write-only files; this avoids
 * worries about ungetc buffers and so forth.
 */
static int
BSD__sbprintf(register FILE *fp, const char *fmt, va_list ap)
{
/* We don't support files. */
        return 0;
}


/*
 * Macros for converting digits to letters and vice versa
 */
#define to_digit(c)     ((c) - '0')
#define is_digit(c)     ((unsigned)to_digit(c) <= 9)
#define to_char(n)      (char)((n) + '0')

#ifdef _HAVE_SANE_QUAD_
/*
 * Convert an unsigned long long to ASCII for printf purposes, returning
 * a pointer to the first character of the string representation.
 * Octal numbers can be forced to have a leading zero; hex numbers
 * use the given digits.
 */
static char *
BSD__uqtoa(register u_quad_t val, char *endp, int base, int octzero, const char *xdigs)
{
        register char *cp = endp;
        register quad_t sval;

        /*
         * Handle the three cases separately, in the hope of getting
         * better/faster code.
         */
        switch (base) {
        case 10:
                if (val < 10) { /* many numbers are 1 digit */
                        *--cp = to_char(val);
                        return (cp);
                }
                /*
                 * On many machines, unsigned arithmetic is harder than
                 * signed arithmetic, so we do at most one unsigned mod and
                 * divide; this is sufficient to reduce the range of
                 * the incoming value to where signed arithmetic works.
                 */
                if (val > LLONG_MAX) {
                        *--cp = to_char(val % 10);
                        sval = val / 10;
                } else
                        sval = val;
                do {
                        *--cp = to_char(sval % 10);
                        sval /= 10;
                } while (sval != 0);
                break;

        case 8:
                do {
                        *--cp = to_char(val & 7);
                        val >>= 3;
                } while (val);
                if (octzero && *cp != '0')
                        *--cp = '0';
                break;

        case 16:
                do {
                        *--cp = xdigs[val & 15];
                        val >>= 4;
                } while (val);
                break;

        default:                        /* oops */
                /*
                abort();
                */
                break;  /* fjc 7-31-97.  Don't reference abort() here */
        }
        return (cp);
}
#endif /* _HAVE_SANE_QUAD_ */

/*
 * Convert an unsigned long to ASCII for printf purposes, returning
 * a pointer to the first character of the string representation.
 * Octal numbers can be forced to have a leading zero; hex numbers
 * use the given digits.
 */
static char *
BSD__ultoa(register u_long val, char *endp, int base, int octzero, const char *xdigs)
{
        register char *cp = endp;
        register long sval;

        /*
         * Handle the three cases separately, in the hope of getting
         * better/faster code.
         */
        switch (base) {
        case 10:
                if (val < 10) { /* many numbers are 1 digit */
                        *--cp = to_char(val);
                        return (cp);
                }
                /*
                 * On many machines, unsigned arithmetic is harder than
                 * signed arithmetic, so we do at most one unsigned mod and
                 * divide; this is sufficient to reduce the range of
                 * the incoming value to where signed arithmetic works.
                 */
                if (val > LONG_MAX) {
                        *--cp = to_char(val % 10);
                        sval = val / 10;
                } else
                        sval = val;
                do {
                        *--cp = to_char(sval % 10);
                        sval /= 10;
                } while (sval != 0);
                break;

        case 8:
                do {
                        *--cp = to_char(val & 7);
                        val >>= 3;
                } while (val);
                if (octzero && *cp != '0')
                        *--cp = '0';
                break;

        case 16:
                do {
                        *--cp = xdigs[val & 15];
                        val >>= 4;
                } while (val);
                break;

        default:                        /* oops */
                /*
                abort();
                */
                break;  /* fjc 7-31-97.  Don't reference abort() here */
        }
        return (cp);
}

#ifdef FLOATING_POINT
#include <math.h>
/* #include "floatio.h" */

#ifndef MAXEXP
# define MAXEXP 1024
#endif

#ifndef MAXFRACT
# define MAXFRACT 64
#endif

#define BUF             (MAXEXP+MAXFRACT+1)     /* + decimal point */
#define DEFPREC         6

static char *cvt __P((double, int, int, char *, int *, int, int *, char *));
static int exponent __P((char *, int, int));

#else /* no FLOATING_POINT */

#define BUF             68

#endif /* FLOATING_POINT */


/*
 * Flags used during conversion.
 */
#define ALT             0x001           /* alternate form */
#define HEXPREFIX       0x002           /* add 0x or 0X prefix */
#define LADJUST         0x004           /* left adjustment */
#define LONGDBL         0x008           /* long double; unimplemented */
#define LONGINT         0x010           /* long integer */

#ifdef _HAVE_SANE_QUAD_
#define QUADINT         0x020           /* quad integer */
#endif /* _HAVE_SANE_QUAD_ */

#define SHORTINT        0x040           /* short integer */
#define ZEROPAD         0x080           /* zero (as opposed to blank) pad */
#define FPT             0x100           /* Floating point number */
static ssize_t
BSD_vfprintf(FILE *fp, const char *fmt0, va_list ap)
{
        register const char *fmt; /* format string */
        register int ch;        /* character from fmt */
        register int n;         /* handy integer (short term usage) */
        register const char *cp;/* handy char pointer (short term usage) */
        register struct __siov *iovp;/* for PRINT macro */
        register int flags;     /* flags as above */
        ssize_t ret;            /* return value accumulator */
        int width;              /* width from format (%8d), or 0 */
        int prec;               /* precision from format (%.3d), or -1 */
        char sign;              /* sign prefix (' ', '+', '-', or \0) */
#ifdef FLOATING_POINT
        char softsign;          /* temporary negative sign for floats */
        double _double = 0;     /* double precision arguments %[eEfgG] */
        int expt;               /* integer value of exponent */
        int expsize = 0;        /* character count for expstr */
        int ndig = 0;           /* actual number of digits returned by cvt */
        char expstr[7];         /* buffer for exponent string */
#endif
        u_long  ulval;          /* integer arguments %[diouxX] */
#ifdef _HAVE_SANE_QUAD_
        u_quad_t uqval;         /* %q integers */
#endif /* _HAVE_SANE_QUAD_ */
        int base;               /* base for [diouxX] conversion */
        int dprec;              /* a copy of prec if [diouxX], 0 otherwise */
        long fieldsz;           /* field size expanded by sign, etc */
        long realsz;            /* field size expanded by dprec */
        int size;               /* size of converted field or string */
        const char *xdigs = 0;  /* digits for [xX] conversion */
#define NIOV 8
        struct __suio uio;      /* output information: summary */
        struct __siov iov[NIOV];/* ... and individual io vectors */
        char buf[BUF];          /* space for %c, %[diouxX], %[eEfgG] */
        char ox[4];             /* space for 0x hex-prefix, hexadecimal's 1. */
        char *const ebuf = buf + sizeof(buf);
#if SIZEOF_LONG > SIZEOF_INT
        long ln;
#endif

        /*
         * Choose PADSIZE to trade efficiency vs. size.  If larger printf
         * fields occur frequently, increase PADSIZE and make the initializers
         * below longer.
         */
#define PADSIZE 16              /* pad chunk size */
        static const char blanks[PADSIZE] =
         {' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '};
        static const char zeroes[PADSIZE] =
         {'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'};

        /*
         * BEWARE, these `goto error' on error, and PAD uses `n'.
         */
#define PRINT(ptr, len) { \
        iovp->iov_base = (ptr); \
        iovp->iov_len = (len); \
        uio.uio_resid += (len); \
        iovp++; \
        if (++uio.uio_iovcnt >= NIOV) { \
                if (BSD__sprint(fp, &uio)) \
                        goto error; \
                iovp = iov; \
        } \
}
#define PAD(howmany, with) { \
        if ((n = (howmany)) > 0) { \
                while (n > PADSIZE) { \
                        PRINT(with, PADSIZE); \
                        n -= PADSIZE; \
                } \
                PRINT(with, n); \
        } \
}
#if SIZEOF_LONG > SIZEOF_INT
        /* abandon if too larger padding */
#define PAD_L(howmany, with) { \
        ln = (howmany); \
        if ((long)((int)ln) != ln) { \
            errno = ENOMEM; \
            goto error; \
        } \
        if (ln > 0) PAD((int)ln, with); \
}
#else
#define PAD_L(howmany, with) PAD(howmany, with)
#endif
#define FLUSH() { \
        if (uio.uio_resid && BSD__sprint(fp, &uio)) \
                goto error; \
        uio.uio_iovcnt = 0; \
        iovp = iov; \
}

        /*
         * To extend shorts properly, we need both signed and unsigned
         * argument extraction methods.
         */
#define SARG() \
        (flags&LONGINT ? va_arg(ap, long) : \
            flags&SHORTINT ? (long)(short)va_arg(ap, int) : \
            (long)va_arg(ap, int))
#define UARG() \
        (flags&LONGINT ? va_arg(ap, u_long) : \
            flags&SHORTINT ? (u_long)(u_short)va_arg(ap, int) : \
            (u_long)va_arg(ap, u_int))

        /* optimise fprintf(stderr) (and other unbuffered Unix files) */
        if ((fp->_flags & (__SNBF|__SWR|__SRW)) == (__SNBF|__SWR) &&
            fp->_file >= 0)
                return (BSD__sbprintf(fp, fmt0, ap));

        fmt = fmt0;
        uio.uio_iov = iovp = iov;
        uio.uio_resid = 0;
        uio.uio_iovcnt = 0;
        ret = 0;
        xdigs = 0;

        /*
         * Scan the format for conversions (`%' character).
         */
        for (;;) {
                size_t nc;
                for (cp = fmt; (ch = *fmt) != '\0' && ch != '%'; fmt++)
                        /* void */;
                if ((nc = fmt - cp) != 0) {
                        PRINT(cp, nc);
                        ret += nc;
                }
                if (ch == '\0')
                        goto done;
                fmt++;          /* skip over '%' */

                flags = 0;
                dprec = 0;
                width = 0;
                prec = -1;
                sign = '\0';

rflag:          ch = *fmt++;
reswitch:       switch (ch) {
                case ' ':
                        /*
                         * ``If the space and + flags both appear, the space
                         * flag will be ignored.''
                         *      -- ANSI X3J11
                         */
                        if (!sign)
                                sign = ' ';
                        goto rflag;
                case '#':
                        flags |= ALT;
                        goto rflag;
                case '*':
                        /*
                         * ``A negative field width argument is taken as a
                         * - flag followed by a positive field width.''
                         *      -- ANSI X3J11
                         * They don't exclude field widths read from args.
                         */
                        if ((width = va_arg(ap, int)) >= 0)
                                goto rflag;
                        width = -width;
                        /* FALLTHROUGH */
                case '-':
                        flags |= LADJUST;
                        goto rflag;
                case '+':
                        sign = '+';
                        goto rflag;
                case '.':
                        if ((ch = *fmt++) == '*') {
                                n = va_arg(ap, int);
                                prec = n < 0 ? -1 : n;
                                goto rflag;
                        }
                        n = 0;
                        while (is_digit(ch)) {
                                n = 10 * n + to_digit(ch);
                                ch = *fmt++;
                        }
                        prec = n < 0 ? -1 : n;
                        goto reswitch;
                case '0':
                        /*
                         * ``Note that 0 is taken as a flag, not as the
                         * beginning of a field width.''
                         *      -- ANSI X3J11
                         */
                        flags |= ZEROPAD;
                        goto rflag;
                case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        n = 0;
                        do {
                                n = 10 * n + to_digit(ch);
                                ch = *fmt++;
                        } while (is_digit(ch));
                        width = n;
                        goto reswitch;
#ifdef FLOATING_POINT
                case 'L':
                        flags |= LONGDBL;
                        goto rflag;
#endif
                case 'h':
                        flags |= SHORTINT;
                        goto rflag;
#if SIZEOF_PTRDIFF_T == SIZEOF_LONG
                case 't':
#endif
#if SIZEOF_SIZE_T == SIZEOF_LONG
                case 'z':
#endif
                case 'l':
                        flags |= LONGINT;
                        goto rflag;
#ifdef _HAVE_SANE_QUAD_
#if SIZEOF_PTRDIFF_T == SIZEOF_LONG_LONG
                case 't':
#endif
#if SIZEOF_SIZE_T == SIZEOF_LONG_LONG
                case 'z':
#endif
                case 'q':
                        flags |= QUADINT;
                        goto rflag;
#endif /* _HAVE_SANE_QUAD_ */
                case 'c':
                        cp = buf;
                        *buf = (char)va_arg(ap, int);
                        size = 1;
                        sign = '\0';
                        break;
                case 'D':
                        flags |= LONGINT;
                        /*FALLTHROUGH*/
                case 'd':
                case 'i':
#ifdef _HAVE_SANE_QUAD_
                        if (flags & QUADINT) {
                                uqval = va_arg(ap, quad_t);
                                if ((quad_t)uqval < 0) {
                                        uqval = -(quad_t)uqval;
                                        sign = '-';
                                }
                        } else
#endif /* _HAVE_SANE_QUAD_ */
                        {
                                ulval = SARG();
                                if ((long)ulval < 0) {
                                        ulval = (u_long)(-(long)ulval);
                                        sign = '-';
                                }
                        }
                        base = 10;
                        goto number;
#ifdef FLOATING_POINT
                case 'a':
                case 'A':
                        if (prec >= 0)
                                prec++;
                        goto fp_begin;
                case 'e':               /* anomalous precision */
                case 'E':
                        if (prec != 0)
                                flags |= ALT;
                        prec = (prec == -1) ?
                                DEFPREC + 1 : prec + 1;
                        /* FALLTHROUGH */
                        goto fp_begin;
                case 'f':               /* always print trailing zeroes */
                        if (prec != 0)
                                flags |= ALT;
                case 'g':
                case 'G':
                        if (prec == -1)
                                prec = DEFPREC;
fp_begin:               _double = va_arg(ap, double);
                        /* do this before tricky precision changes */
                        if (isinf(_double)) {
                                if (_double < 0)
                                        sign = '-';
                                cp = "Inf";
                                size = 3;
                                break;
                        }
                        if (isnan(_double)) {
                                cp = "NaN";
                                size = 3;
                                break;
                        }
                        flags |= FPT;
                        cp = cvt(_double, prec, flags, &softsign,
                                &expt, ch, &ndig, buf);
                        if (ch == 'g' || ch == 'G') {
                                if (expt <= -4 || (expt > prec && expt > 1))
                                        ch = (ch == 'g') ? 'e' : 'E';
                                else
                                        ch = 'g';
                        }
                        if (ch == 'a' || ch == 'A') {
                                --expt;
                                expsize = exponent(expstr, expt, ch + 'p' - 'a');
                                size = expsize + ndig;
                        }
                        else if (ch <= 'e') {   /* 'e' or 'E' fmt */
                                --expt;
                                expsize = exponent(expstr, expt, ch);
                                size = expsize + ndig;
                                if (ndig > 1 || flags & ALT)
                                        ++size;
                        } else if (ch == 'f') {         /* f fmt */
                                if (expt > 0) {
                                        size = expt;
                                        if (prec || flags & ALT)
                                                size += prec + 1;
                                } else if (!prec) { /* "0" */
                                        size = 1;
                                } else  /* "0.X" */
                                        size = prec + 2;
                        } else if (expt >= ndig) {      /* fixed g fmt */
                                size = expt;
                                if (flags & ALT)
                                        ++size;
                        } else
                                size = ndig + (expt > 0 ?
                                        1 : 2 - expt);

                        if (softsign)
                                sign = '-';
                        break;
#endif /* FLOATING_POINT */
                case 'n':
#ifdef _HAVE_SANE_QUAD_
                        if (flags & QUADINT)
                                *va_arg(ap, quad_t *) = ret;
                        else if (flags & LONGINT)
#else /* _HAVE_SANE_QUAD_ */
                        if (flags & LONGINT)
#endif /* _HAVE_SANE_QUAD_ */
                                *va_arg(ap, long *) = ret;
                        else if (flags & SHORTINT)
                                *va_arg(ap, short *) = (short)ret;
                        else
                                *va_arg(ap, int *) = (int)ret;
                        continue;       /* no output */
                case 'O':
                        flags |= LONGINT;
                        /*FALLTHROUGH*/
                case 'o':
#ifdef _HAVE_SANE_QUAD_
                        if (flags & QUADINT)
                                uqval = va_arg(ap, u_quad_t);
                        else
#endif /* _HAVE_SANE_QUAD_ */
                                ulval = UARG();
                        base = 8;
                        goto nosign;
                case 'p':
                        /*
                         * ``The argument shall be a pointer to void.  The
                         * value of the pointer is converted to a sequence
                         * of printable characters, in an implementation-
                         * defined manner.''
                         *      -- ANSI X3J11
                         */
                        prec = (int)(sizeof(void*)*CHAR_BIT/4);
#ifdef _HAVE_LLP64_
                        uqval = (u_quad_t)va_arg(ap, void *);
                        flags = (flags) | QUADINT | HEXPREFIX;
#else
                        ulval = (u_long)va_arg(ap, void *);
#ifdef _HAVE_SANE_QUAD_
                        flags = (flags & ~QUADINT) | HEXPREFIX;
#else /* _HAVE_SANE_QUAD_ */
                        flags = (flags) | HEXPREFIX;
#endif /* _HAVE_SANE_QUAD_ */
#endif
                        base = 16;
                        xdigs = "0123456789abcdef";
                        ch = 'x';
                        goto nosign;
                case 's':
                        if ((cp = va_arg(ap, char *)) == NULL)
                                cp = "(null)";
                        if (prec >= 0) {
                                /*
                                 * can't use strlen; can only look for the
                                 * NUL in the first `prec' characters, and
                                 * strlen() will go further.
                                 */
                                const char *p = (char *)memchr(cp, 0, prec);

                                if (p != NULL && (p - cp) > prec)
                                        size = (int)(p - cp);
                                else
                                        size = prec;
                        }
                        else {
                                fieldsz = strlen(cp);
                                goto long_len;
                        }
                        sign = '\0';
                        break;
                case 'U':
                        flags |= LONGINT;
                        /*FALLTHROUGH*/
                case 'u':
#ifdef _HAVE_SANE_QUAD_
                        if (flags & QUADINT)
                                uqval = va_arg(ap, u_quad_t);
                        else
#endif /* _HAVE_SANE_QUAD_ */
                                ulval = UARG();
                        base = 10;
                        goto nosign;
                case 'X':
                        xdigs = "0123456789ABCDEF";
                        goto hex;
                case 'x':
                        xdigs = "0123456789abcdef";
hex:
#ifdef _HAVE_SANE_QUAD_
                        if (flags & QUADINT)
                                uqval = va_arg(ap, u_quad_t);
                        else
#endif /* _HAVE_SANE_QUAD_ */
                                ulval = UARG();
                        base = 16;
                        /* leading 0x/X only if non-zero */
                        if (flags & ALT &&
#ifdef _HAVE_SANE_QUAD_
                            (flags & QUADINT ? uqval != 0 : ulval != 0)
#else /* _HAVE_SANE_QUAD_ */
                            ulval != 0
#endif /* _HAVE_SANE_QUAD_ */
                            )
                                flags |= HEXPREFIX;

                        /* unsigned conversions */
nosign:                 sign = '\0';
                        /*
                         * ``... diouXx conversions ... if a precision is
                         * specified, the 0 flag will be ignored.''
                         *      -- ANSI X3J11
                         */
number:                 if ((dprec = prec) >= 0)
                                flags &= ~ZEROPAD;

                        /*
                         * ``The result of converting a zero value with an
                         * explicit precision of zero is no characters.''
                         *      -- ANSI X3J11
                         */
#ifdef _HAVE_SANE_QUAD_
                        if (flags & QUADINT) {
                                if (uqval != 0 || prec != 0)
                                        cp = BSD__uqtoa(uqval, ebuf, base,
                                            flags & ALT, xdigs);
                        } else
#else /* _HAVE_SANE_QUAD_ */
#endif /* _HAVE_SANE_QUAD_ */
                        {
                                if (ulval != 0 || prec != 0)
                                        cp = BSD__ultoa(ulval, ebuf, base,
                                            flags & ALT, xdigs);
                        }
                        size = (int)(ebuf - cp);
                        break;
                default:        /* "%?" prints ?, unless ? is NUL */
                        if (ch == '\0')
                                goto done;
                        /* pretend it was %c with argument ch */
                        cp = buf;
                        *buf = ch;
                        size = 1;
                        sign = '\0';
                        break;
                }

                /*
                 * All reasonable formats wind up here.  At this point, `cp'
                 * points to a string which (if not flags&LADJUST) should be
                 * padded out to `width' places.  If flags&ZEROPAD, it should
                 * first be prefixed by any sign or other prefix; otherwise,
                 * it should be blank padded before the prefix is emitted.
                 * After any left-hand padding and prefixing, emit zeroes
                 * required by a decimal [diouxX] precision, then print the
                 * string proper, then emit zeroes required by any leftover
                 * floating precision; finally, if LADJUST, pad with blanks.
                 *
                 * Compute actual size, so we know how much to pad.
                 * fieldsz excludes decimal prec; realsz includes it.
                 */
                fieldsz = size;
long_len:
                if (sign)
                        fieldsz++;
                else if (flags & HEXPREFIX)
                        fieldsz += 2;
                realsz = dprec > fieldsz ? dprec : fieldsz;

                /* right-adjusting blank padding */
                if ((flags & (LADJUST|ZEROPAD)) == 0)
                        PAD_L(width - realsz, blanks);

                /* prefix */
                if (sign) {
                        PRINT(&sign, 1);
                } else if (flags & HEXPREFIX) {
                        ox[0] = '0';
                        ox[1] = ch;
                        PRINT(ox, 2);
                }

                /* right-adjusting zero padding */
                if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD)
                        PAD_L(width - realsz, zeroes);

                /* leading zeroes from decimal precision */
                PAD_L(dprec - fieldsz, zeroes);
                if (sign)
                        fieldsz--;
                else if (flags & HEXPREFIX)
                        fieldsz -= 2;

                /* the string or number proper */
#ifdef FLOATING_POINT
                if ((flags & FPT) == 0) {
                        PRINT(cp, fieldsz);
                } else {        /* glue together f_p fragments */
                        if (ch == 'a' || ch == 'A') {
                                ox[0] = '0';
                                ox[1] = ch + ('x' - 'a');
                                PRINT(ox, 2);
                                if (ndig > 1 || flags & ALT) {
                                        ox[2] = *cp++;
                                        ox[3] = '.';
                                        PRINT(ox+2, 2);
                                        PRINT(cp, ndig-1);
                                } else  /* XpYYY */
                                        PRINT(cp, 1);
                                PRINT(expstr, expsize);
                        }
                        else if (ch >= 'f') {   /* 'f' or 'g' */
                                if (_double == 0) {
                                /* kludge for __dtoa irregularity */
                                        if (ndig <= 1 &&
                                            (flags & ALT) == 0) {
                                                PRINT("0", 1);
                                        } else {
                                                PRINT("0.", 2);
                                                PAD(ndig - 1, zeroes);
                                        }
                                } else if (expt == 0 && ndig == 0 && (flags & ALT) == 0) {
                                        PRINT("0", 1);
                                } else if (expt <= 0) {
                                        PRINT("0.", 2);
                                        PAD(-expt, zeroes);
                                        PRINT(cp, ndig);
                                } else if (expt >= ndig) {
                                        PRINT(cp, ndig);
                                        PAD(expt - ndig, zeroes);
                                        if (flags & ALT)
                                                PRINT(".", 1);
                                } else {
                                        PRINT(cp, expt);
                                        cp += expt;
                                        PRINT(".", 1);
                                        PRINT(cp, ndig-expt);
                                }
                        } else {        /* 'e' or 'E' */
                                if (ndig > 1 || flags & ALT) {
                                        ox[0] = *cp++;
                                        ox[1] = '.';
                                        PRINT(ox, 2);
                                        if (_double /*|| flags & ALT == 0*/) {
                                                PRINT(cp, ndig-1);
                                        } else  /* 0.[0..] */
                                                /* __dtoa irregularity */
                                                PAD(ndig - 1, zeroes);
                                } else  /* XeYYY */
                                        PRINT(cp, 1);
                                PRINT(expstr, expsize);
                        }
                }
#else
                PRINT(cp, fieldsz);
#endif
                /* left-adjusting padding (always blank) */
                if (flags & LADJUST)
                        PAD_L(width - realsz, blanks);

                /* finally, adjust ret */
                ret += width > realsz ? width : realsz;

                FLUSH();        /* copy out the I/O vectors */
        }
done:
        FLUSH();
error:
        return (__sferror(fp) ? EOF : ret);
        /* NOTREACHED */
}

#ifdef FLOATING_POINT

extern char *BSD__dtoa __P((double, int, int, int *, int *, char **));
extern char *BSD__hdtoa(double, const char *, int, int *, int *, char **);

static char *
cvt(value, ndigits, flags, sign, decpt, ch, length, buf)
        double value;
        int ndigits, flags, *decpt, ch, *length;
        char *sign, *buf;
{
        int mode, dsgn;
        char *digits, *bp, *rve;

        if (ch == 'f')
                mode = 3;
        else {
                mode = 2;
        }
        if (value < 0) {
                value = -value;
                *sign = '-';
        } else if (value == 0.0 && 1.0/value < 0) {
            *sign = '-';
        } else {
            *sign = '\000';
        }
        if (ch == 'a' || ch =='A') {
            digits = BSD__hdtoa(value,
                    ch == 'a' ? "0123456789abcdef" : "0123456789ABCDEF",
                    ndigits, decpt, &dsgn, &rve);
        }
        else {
            digits = BSD__dtoa(value, mode, ndigits, decpt, &dsgn, &rve);
        }
        buf[0] = 0; /* rve - digits may be 0 */
        memcpy(buf, digits, rve - digits);
        xfree(digits);
        rve = buf + (rve - digits);
        digits = buf;
        if (flags & ALT) {      /* Print trailing zeros */
                bp = digits + ndigits;
                if (ch == 'f') {
                        if (*digits == '0' && value)
                                *decpt = -ndigits + 1;
                        bp += *decpt;
                }
                if (value == 0) /* kludge for __dtoa irregularity */
                        rve = bp;
                while (rve < bp)
                        *rve++ = '0';
        }
        *length = (int)(rve - digits);
        return (digits);
}

static int
exponent(p0, exp, fmtch)
        char *p0;
        int exp, fmtch;
{
        register char *p, *t;
        char expbuf[MAXEXP];

        p = p0;
        *p++ = fmtch;
        if (exp < 0) {
                exp = -exp;
                *p++ = '-';
        }
        else
                *p++ = '+';
        t = expbuf + MAXEXP;
        if (exp > 9) {
                do {
                        *--t = to_char(exp % 10);
                } while ((exp /= 10) > 9);
                *--t = to_char(exp);
                for (; t < expbuf + MAXEXP; *p++ = *t++);
        }
        else {
                if (fmtch & 15) *p++ = '0'; /* other than p or P */
                *p++ = to_char(exp);
        }
        return (int)(p - p0);
}
#endif /* FLOATING_POINT */

int
ruby_vsnprintf(char *str, size_t n, const char *fmt, va_list ap)
{
        int ret;
        FILE f;

        if ((int)n < 1)
                return (EOF);
        f._flags = __SWR | __SSTR;
        f._bf._base = f._p = (unsigned char *)str;
        f._bf._size = f._w = n - 1;
        f.vwrite = BSD__sfvwrite;
        ret = (int)BSD_vfprintf(&f, fmt, ap);
        *f._p = 0;
        return (ret);
}

int
ruby_snprintf(char *str, size_t n, char const *fmt, ...)
{
        int ret;
        va_list ap;
        FILE f;

        if ((int)n < 1)
                return (EOF);

        va_start(ap, fmt);
        f._flags = __SWR | __SSTR;
        f._bf._base = f._p = (unsigned char *)str;
        f._bf._size = f._w = n - 1;
        f.vwrite = BSD__sfvwrite;
        ret = (int)BSD_vfprintf(&f, fmt, ap);
        *f._p = 0;
        va_end(ap);
        return (ret);
}