u_snprintf.c

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/*
 * Copyright (c) 1995 Patrick Powell.
 *
 * 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.
 */

/*
 * Copyright (c) 2008 Holger Weiss.
 *
 * This version of the code is maintained by Holger Weiss <holger@jhweiss.de>.
 * My changes to the code may freely be used, modified and/or redistributed for
 * any purpose.  It would be nice if additions and fixes to this file (including
 * trivial code cleanups) would be sent back in order to let me include them in
 * the version available at <http://www.jhweiss.de/software/snprintf.html>.
 * However, this is not a requirement for using or redistributing (possibly
 * modified) versions of this file, nor is leaving this notice intact mandatory.
 */

/*
 * History
 *
 * 2008-01-20 Holger Weiss <holger@jhweiss.de> for C99-snprintf 1.1:
 *
 *      Fixed the detection of infinite floating point values on IRIX (and
 *      possibly other systems) and applied another few minor cleanups.
 *
 * 2008-01-06 Holger Weiss <holger@jhweiss.de> for C99-snprintf 1.0:
 *
 *      Added a lot of new features, fixed many bugs, and incorporated various
 *      improvements done by Andrew Tridgell <tridge@samba.org>, Russ Allbery
 *      <rra@stanford.edu>, Hrvoje Niksic <hniksic@xemacs.org>, Damien Miller
 *      <djm@mindrot.org>, and others for the Samba, INN, Wget, and OpenSSH
 *      projects.  The additions include: support the "e", "E", "g", "G", and
 *      "F" conversion specifiers (and use conversion style "f" or "F" for the
 *      still unsupported "a" and "A" specifiers); support the "hh", "ll", "j",
 *      "t", and "z" length modifiers; support the "#" flag and the (non-C99)
 *      "'" flag; use localeconv(3) (if available) to get both the current
 *      locale's decimal point character and the separator between groups of
 *      digits; fix the handling of various corner cases of field width and
 *      precision specifications; fix various floating point conversion bugs;
 *      handle infinite and NaN floating point values; don't attempt to write to
 *      the output buffer (which may be NULL) if a size of zero was specified;
 *      check for integer overflow of the field width, precision, and return
 *      values and during the floating point conversion; use the OUTCHAR() macro
 *      instead of a function for better performance; provide asprintf(3) and
 *      vasprintf(3) functions; add new test cases.  The replacement functions
 *      have been renamed to use an "rpl_" prefix, the function calls in the
 *      main project (and in this file) must be redefined accordingly for each
 *      replacement function which is needed (by using Autoconf or other means).
 *      Various other minor improvements have been applied and the coding style
 *      was cleaned up for consistency.
 *
 * 2007-07-23 Holger Weiss <holger@jhweiss.de> for Mutt 1.5.13:
 *
 *      C99 compliant snprintf(3) and vsnprintf(3) functions return the number
 *      of characters that would have been written to a sufficiently sized
 *      buffer (excluding the '\0').  The original code simply returned the
 *      length of the resulting output string, so that's been fixed.
 *
 * 1998-03-05 Michael Elkins <me@mutt.org> for Mutt 0.90.8:
 *
 *      The original code assumed that both snprintf(3) and vsnprintf(3) were
 *      missing.  Some systems only have snprintf(3) but not vsnprintf(3), so
 *      the code is now broken down under HAVE_SNPRINTF and HAVE_VSNPRINTF.
 *
 * 1998-01-27 Thomas Roessler <roessler@does-not-exist.org> for Mutt 0.89i:
 *
 *      The PGP code was using unsigned hexadecimal formats.  Unfortunately,
 *      unsigned formats simply didn't work.
 *
 * 1997-10-22 Brandon Long <blong@fiction.net> 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, run with:
 *      gcc -DTEST_SNPRINTF -o snprintf snprintf.c -lm && ./snprintf
 *
 * 2996-09-15 Brandon Long <blong@fiction.net> 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.
 */

/*
 * ToDo
 *
 * - Add wide character support.
 * - Add support for "%a" and "%A" conversions.
 * - Create test routines which predefine the expected results.  Our test cases
 *   usually expose bugs in system implementations rather than in ours :-)
 */

/*
 * Usage
 *
 * 1) The following preprocessor macros should be defined to 1 if the feature or
 *    file in question is available on the target system (by using Autoconf or
 *    other means), though basic functionality should be available as long as
 *    HAVE_STDARG_H and HAVE_STDLIB_H are defined correctly:
 *
 *      HAVE_VSNPRINTF
 *      HAVE_SNPRINTF
 *      HAVE_VASPRINTF
 *      HAVE_ASPRINTF
 *      HAVE_STDARG_H
 *      HAVE_STDDEF_H
 *      HAVE_STDINT_H
 *      HAVE_STDLIB_H
 *      HAVE_INTTYPES_H
 *      HAVE_LOCALE_H
 *      HAVE_LOCALECONV
 *      HAVE_LCONV_DECIMAL_POINT
 *      HAVE_LCONV_THOUSANDS_SEP
 *      HAVE_LONG_DOUBLE
 *      HAVE_LONG_LONG_INT
 *      HAVE_UNSIGNED_LONG_LONG_INT
 *      HAVE_INTMAX_T
 *      HAVE_UINTMAX_T
 *      HAVE_UINTPTR_T
 *      HAVE_PTRDIFF_T
 *      HAVE_VA_COPY
 *      HAVE___VA_COPY
 *
 * 2) The calls to the functions which should be replaced must be redefined
 *    throughout the project files (by using Autoconf or other means):
 *
 *      #define vsnprintf rpl_vsnprintf
 *      #define snprintf rpl_snprintf
 *      #define vasprintf rpl_vasprintf
 *      #define asprintf rpl_asprintf
 *
 * 3) The required replacement functions should be declared in some header file
 *    included throughout the project files:
 *
 *      #if HAVE_CONFIG_H
 *      #include <config.h>
 *      #endif
 *      #if HAVE_STDARG_H
 *      #include <stdarg.h>
 *      #if !HAVE_VSNPRINTF
 *      int rpl_vsnprintf(char *, size_t, const char *, va_list);
 *      #endif
 *      #if !HAVE_SNPRINTF
 *      int rpl_snprintf(char *, size_t, const char *, ...);
 *      #endif
 *      #if !HAVE_VASPRINTF
 *      int rpl_vasprintf(char **, const char *, va_list);
 *      #endif
 *      #if !HAVE_ASPRINTF
 *      int rpl_asprintf(char **, const char *, ...);
 *      #endif
 *      #endif
 *
 * Autoconf macros for handling step 1 and step 2 are available at
 * <http://www.jhweiss.de/software/snprintf.html>.
 */

#include "pipe/p_config.h"

#if HAVE_CONFIG_H
#include <config.h>
#else
#ifdef WIN32
#define vsnprintf util_vsnprintf
#define snprintf util_snprintf
#define HAVE_VSNPRINTF 0
#define HAVE_SNPRINTF 0
#define HAVE_VASPRINTF 1 /* not needed */
#define HAVE_ASPRINTF 1 /* not needed */
#define HAVE_STDARG_H 1
#define HAVE_STDDEF_H 1
#define HAVE_STDINT_H 0
#define HAVE_STDLIB_H 1
#define HAVE_INTTYPES_H 0
#define HAVE_LOCALE_H 0
#define HAVE_LOCALECONV 0
#define HAVE_LCONV_DECIMAL_POINT 0
#define HAVE_LCONV_THOUSANDS_SEP 0
#define HAVE_LONG_DOUBLE 0
#define HAVE_LONG_LONG_INT 1
#define HAVE_UNSIGNED_LONG_LONG_INT 1
#define HAVE_INTMAX_T 0
#define HAVE_UINTMAX_T 0
#define HAVE_UINTPTR_T 1
#define HAVE_PTRDIFF_T 1
#define HAVE_VA_COPY 0
#define HAVE___VA_COPY 0
#else
#define HAVE_VSNPRINTF 1
#define HAVE_SNPRINTF 1
#define HAVE_VASPRINTF 1
#define HAVE_ASPRINTF 1
#endif
#endif  /* HAVE_CONFIG_H */

#if !HAVE_SNPRINTF || !HAVE_VSNPRINTF || !HAVE_ASPRINTF || !HAVE_VASPRINTF
#include <stdio.h>      /* For NULL, size_t, vsnprintf(3), and vasprintf(3). */
#ifdef VA_START
#undef VA_START
#endif  /* defined(VA_START) */
#ifdef VA_SHIFT
#undef VA_SHIFT
#endif  /* defined(VA_SHIFT) */
#if HAVE_STDARG_H
#include <stdarg.h>
#define VA_START(ap, last) va_start(ap, last)
#define VA_SHIFT(ap, value, type) /* No-op for ANSI C. */
#else   /* Assume <varargs.h> is available. */
#include <varargs.h>
#define VA_START(ap, last) va_start(ap) /* "last" is ignored. */
#define VA_SHIFT(ap, value, type) value = va_arg(ap, type)
#endif  /* HAVE_STDARG_H */

#if !HAVE_VASPRINTF
#if HAVE_STDLIB_H
#include <stdlib.h>     /* For malloc(3). */
#endif  /* HAVE_STDLIB_H */
#ifdef VA_COPY
#undef VA_COPY
#endif  /* defined(VA_COPY) */
#ifdef VA_END_COPY
#undef VA_END_COPY
#endif  /* defined(VA_END_COPY) */
#if HAVE_VA_COPY
#define VA_COPY(dest, src) va_copy(dest, src)
#define VA_END_COPY(ap) va_end(ap)
#elif HAVE___VA_COPY
#define VA_COPY(dest, src) __va_copy(dest, src)
#define VA_END_COPY(ap) va_end(ap)
#else
#define VA_COPY(dest, src) (void)mymemcpy(&dest, &src, sizeof(va_list))
#define VA_END_COPY(ap) /* No-op. */
#define NEED_MYMEMCPY 1
static void *mymemcpy(void *, void *, size_t);
#endif  /* HAVE_VA_COPY */
#endif  /* !HAVE_VASPRINTF */

#if !HAVE_VSNPRINTF
#include <limits.h>     /* For *_MAX. */
#if HAVE_INTTYPES_H
#include <inttypes.h>   /* For intmax_t (if not defined in <stdint.h>). */
#endif  /* HAVE_INTTYPES_H */
#if HAVE_LOCALE_H
#include <locale.h>     /* For localeconv(3). */
#endif  /* HAVE_LOCALE_H */
#if HAVE_STDDEF_H
#include <stddef.h>     /* For ptrdiff_t. */
#endif  /* HAVE_STDDEF_H */
#if HAVE_STDINT_H
#include <stdint.h>     /* For intmax_t. */
#endif  /* HAVE_STDINT_H */

/* Support for unsigned long long int.  We may also need ULLONG_MAX. */
#ifndef ULONG_MAX       /* We may need ULONG_MAX as a fallback. */
#ifdef UINT_MAX
#define ULONG_MAX UINT_MAX
#else
#define ULONG_MAX INT_MAX
#endif  /* defined(UINT_MAX) */
#endif  /* !defined(ULONG_MAX) */
#ifdef ULLONG
#undef ULLONG
#endif  /* defined(ULLONG) */
#if HAVE_UNSIGNED_LONG_LONG_INT
#define ULLONG unsigned long long int
#ifndef ULLONG_MAX
#define ULLONG_MAX ULONG_MAX
#endif  /* !defined(ULLONG_MAX) */
#else
#define ULLONG unsigned long int
#ifdef ULLONG_MAX
#undef ULLONG_MAX
#endif  /* defined(ULLONG_MAX) */
#define ULLONG_MAX ULONG_MAX
#endif  /* HAVE_LONG_LONG_INT */

/* Support for uintmax_t.  We also need UINTMAX_MAX. */
#ifdef UINTMAX_T
#undef UINTMAX_T
#endif  /* defined(UINTMAX_T) */
#if HAVE_UINTMAX_T || defined(uintmax_t)
#define UINTMAX_T uintmax_t
#ifndef UINTMAX_MAX
#define UINTMAX_MAX ULLONG_MAX
#endif  /* !defined(UINTMAX_MAX) */
#else
#define UINTMAX_T ULLONG
#ifdef UINTMAX_MAX
#undef UINTMAX_MAX
#endif  /* defined(UINTMAX_MAX) */
#define UINTMAX_MAX ULLONG_MAX
#endif  /* HAVE_UINTMAX_T || defined(uintmax_t) */

/* Support for long double. */
#ifndef LDOUBLE
#if HAVE_LONG_DOUBLE
#define LDOUBLE long double
#else
#define LDOUBLE double
#endif  /* HAVE_LONG_DOUBLE */
#endif  /* !defined(LDOUBLE) */

/* Support for long long int. */
#ifndef LLONG
#if HAVE_LONG_LONG_INT
#define LLONG long long int
#else
#define LLONG long int
#endif  /* HAVE_LONG_LONG_INT */
#endif  /* !defined(LLONG) */

/* Support for intmax_t. */
#ifndef INTMAX_T
#if HAVE_INTMAX_T || defined(intmax_t)
#define INTMAX_T intmax_t
#else
#define INTMAX_T LLONG
#endif  /* HAVE_INTMAX_T || defined(intmax_t) */
#endif  /* !defined(INTMAX_T) */

/* Support for uintptr_t. */
#ifndef UINTPTR_T
#if HAVE_UINTPTR_T || defined(uintptr_t)
#define UINTPTR_T uintptr_t
#else
#define UINTPTR_T unsigned long int
#endif  /* HAVE_UINTPTR_T || defined(uintptr_t) */
#endif  /* !defined(UINTPTR_T) */

/* WinCE5.0 does not have uintptr_t defined */ 
#if (_WIN32_WCE < 600) 
#ifdef UINTPTR_T 
#undef UINTPTR_T 
#endif 
#define UINTPTR_T unsigned long int 
#endif 


/* Support for ptrdiff_t. */
#ifndef PTRDIFF_T
#if HAVE_PTRDIFF_T || defined(ptrdiff_t)
#define PTRDIFF_T ptrdiff_t
#else
#define PTRDIFF_T long int
#endif  /* HAVE_PTRDIFF_T || defined(ptrdiff_t) */
#endif  /* !defined(PTRDIFF_T) */

/*
 * We need an unsigned integer type corresponding to ptrdiff_t (cf. C99:
 * 7.19.6.1, 7).  However, we'll simply use PTRDIFF_T and convert it to an
 * unsigned type if necessary.  This should work just fine in practice.
 */
#ifndef UPTRDIFF_T
#define UPTRDIFF_T PTRDIFF_T
#endif  /* !defined(UPTRDIFF_T) */

/*
 * We need a signed integer type corresponding to size_t (cf. C99: 7.19.6.1, 7).
 * However, we'll simply use size_t and convert it to a signed type if
 * necessary.  This should work just fine in practice.
 */
#ifndef SSIZE_T
#define SSIZE_T size_t
#endif  /* !defined(SSIZE_T) */

/* Either ERANGE or E2BIG should be available everywhere. */
#ifndef ERANGE
#define ERANGE E2BIG
#endif  /* !defined(ERANGE) */
#ifndef EOVERFLOW
#define EOVERFLOW ERANGE
#endif  /* !defined(EOVERFLOW) */

/*
 * Buffer size to hold the octal string representation of UINT128_MAX without
 * nul-termination ("3777777777777777777777777777777777777777777").
 */
#ifdef MAX_CONVERT_LENGTH
#undef MAX_CONVERT_LENGTH
#endif  /* defined(MAX_CONVERT_LENGTH) */
#define MAX_CONVERT_LENGTH      43

/* Format read states. */
#define PRINT_S_DEFAULT         0
#define PRINT_S_FLAGS           1
#define PRINT_S_WIDTH           2
#define PRINT_S_DOT             3
#define PRINT_S_PRECISION       4
#define PRINT_S_MOD             5
#define PRINT_S_CONV            6

/* Format flags. */
#define PRINT_F_MINUS           (1 << 0)
#define PRINT_F_PLUS            (1 << 1)
#define PRINT_F_SPACE           (1 << 2)
#define PRINT_F_NUM             (1 << 3)
#define PRINT_F_ZERO            (1 << 4)
#define PRINT_F_QUOTE           (1 << 5)
#define PRINT_F_UP              (1 << 6)
#define PRINT_F_UNSIGNED        (1 << 7)
#define PRINT_F_TYPE_G          (1 << 8)
#define PRINT_F_TYPE_E          (1 << 9)

/* Conversion flags. */
#define PRINT_C_CHAR            1
#define PRINT_C_SHORT           2
#define PRINT_C_LONG            3
#define PRINT_C_LLONG           4
#define PRINT_C_LDOUBLE         5
#define PRINT_C_SIZE            6
#define PRINT_C_PTRDIFF         7
#define PRINT_C_INTMAX          8

#ifndef MAX
#define MAX(x, y) ((x >= y) ? x : y)
#endif  /* !defined(MAX) */
#ifndef CHARTOINT
#define CHARTOINT(ch) (ch - '0')
#endif  /* !defined(CHARTOINT) */
#ifndef ISDIGIT
#define ISDIGIT(ch) ('0' <= (unsigned char)ch && (unsigned char)ch <= '9')
#endif  /* !defined(ISDIGIT) */
#ifndef ISNAN
#define ISNAN(x) (x != x)
#endif  /* !defined(ISNAN) */
#ifndef ISINF
#define ISINF(x) (x != 0.0 && x + x == x)
#endif  /* !defined(ISINF) */

#ifdef OUTCHAR
#undef OUTCHAR
#endif  /* defined(OUTCHAR) */
#define OUTCHAR(str, len, size, ch)                                          \
do {                                                                         \
        if (len + 1 < size)                                                  \
                str[len] = ch;                                               \
        (len)++;                                                             \
} while (/* CONSTCOND */ 0)

static void fmtstr(char *, size_t *, size_t, const char *, int, int, int);
static void fmtint(char *, size_t *, size_t, INTMAX_T, int, int, int, int);
static void fmtflt(char *, size_t *, size_t, LDOUBLE, int, int, int, int *);
static void printsep(char *, size_t *, size_t);
static int getnumsep(int);
static int getexponent(LDOUBLE);
static int convert(UINTMAX_T, char *, size_t, int, int);
static UINTMAX_T cast(LDOUBLE);
static UINTMAX_T myround(LDOUBLE);
static LDOUBLE mypow10(int);

int
util_vsnprintf(char *str, size_t size, const char *format, va_list args)
{
        LDOUBLE fvalue;
        INTMAX_T value;
        unsigned char cvalue;
        const char *strvalue;
        INTMAX_T *intmaxptr;
        PTRDIFF_T *ptrdiffptr;
        SSIZE_T *sizeptr;
        LLONG *llongptr;
        long int *longptr;
        int *intptr;
        short int *shortptr;
        signed char *charptr;
        size_t len = 0;
        int overflow = 0;
        int base = 0;
        int cflags = 0;
        int flags = 0;
        int width = 0;
        int precision = -1;
        int state = PRINT_S_DEFAULT;
        char ch = *format++;

        /*
         * C99 says: "If `n' is zero, nothing is written, and `s' may be a null
         * pointer." (7.19.6.5, 2)  We're forgiving and allow a NULL pointer
         * even if a size larger than zero was specified.  At least NetBSD's
         * snprintf(3) does the same, as well as other versions of this file.
         * (Though some of these versions will write to a non-NULL buffer even
         * if a size of zero was specified, which violates the standard.)
         */
        if (str == NULL && size != 0)
                size = 0;

        while (ch != '\0')
                switch (state) {
                case PRINT_S_DEFAULT:
                        if (ch == '%')
                                state = PRINT_S_FLAGS;
                        else
                                OUTCHAR(str, len, size, ch);
                        ch = *format++;
                        break;
                case PRINT_S_FLAGS:
                        switch (ch) {
                        case '-':
                                flags |= PRINT_F_MINUS;
                                ch = *format++;
                                break;
                        case '+':
                                flags |= PRINT_F_PLUS;
                                ch = *format++;
                                break;
                        case ' ':
                                flags |= PRINT_F_SPACE;
                                ch = *format++;
                                break;
                        case '#':
                                flags |= PRINT_F_NUM;
                                ch = *format++;
                                break;
                        case '0':
                                flags |= PRINT_F_ZERO;
                                ch = *format++;
                                break;
                        case '\'':      /* SUSv2 flag (not in C99). */
                                flags |= PRINT_F_QUOTE;
                                ch = *format++;
                                break;
                        default:
                                state = PRINT_S_WIDTH;
                                break;
                        }
                        break;
                case PRINT_S_WIDTH:
                        if (ISDIGIT(ch)) {
                                ch = CHARTOINT(ch);
                                if (width > (INT_MAX - ch) / 10) {
                                        overflow = 1;
                                        goto out;
                                }
                                width = 10 * width + ch;
                                ch = *format++;
                        } else if (ch == '*') {
                                /*
                                 * C99 says: "A negative field width argument is
                                 * taken as a `-' flag followed by a positive
                                 * field width." (7.19.6.1, 5)
                                 */
                                if ((width = va_arg(args, int)) < 0) {
                                        flags |= PRINT_F_MINUS;
                                        width = -width;
                                }
                                ch = *format++;
                                state = PRINT_S_DOT;
                        } else
                                state = PRINT_S_DOT;
                        break;
                case PRINT_S_DOT:
                        if (ch == '.') {
                                state = PRINT_S_PRECISION;
                                ch = *format++;
                        } else
                                state = PRINT_S_MOD;
                        break;
                case PRINT_S_PRECISION:
                        if (precision == -1)
                                precision = 0;
                        if (ISDIGIT(ch)) {
                                ch = CHARTOINT(ch);
                                if (precision > (INT_MAX - ch) / 10) {
                                        overflow = 1;
                                        goto out;
                                }
                                precision = 10 * precision + ch;
                                ch = *format++;
                        } else if (ch == '*') {
                                /*
                                 * C99 says: "A negative precision argument is
                                 * taken as if the precision were omitted."
                                 * (7.19.6.1, 5)
                                 */
                                if ((precision = va_arg(args, int)) < 0)
                                        precision = -1;
                                ch = *format++;
                                state = PRINT_S_MOD;
                        } else
                                state = PRINT_S_MOD;
                        break;
                case PRINT_S_MOD:
                        switch (ch) {
                        case 'h':
                                ch = *format++;
                                if (ch == 'h') {        /* It's a char. */
                                        ch = *format++;
                                        cflags = PRINT_C_CHAR;
                                } else
                                        cflags = PRINT_C_SHORT;
                                break;
                        case 'l':
                                ch = *format++;
                                if (ch == 'l') {        /* It's a long long. */
                                        ch = *format++;
                                        cflags = PRINT_C_LLONG;
                                } else
                                        cflags = PRINT_C_LONG;
                                break;
                        case 'L':
                                cflags = PRINT_C_LDOUBLE;
                                ch = *format++;
                                break;
                        case 'j':
                                cflags = PRINT_C_INTMAX;
                                ch = *format++;
                                break;
                        case 't':
                                cflags = PRINT_C_PTRDIFF;
                                ch = *format++;
                                break;
                        case 'z':
                                cflags = PRINT_C_SIZE;
                                ch = *format++;
                                break;
                        }
                        state = PRINT_S_CONV;
                        break;
                case PRINT_S_CONV:
                        switch (ch) {
                        case 'd':
                                /* FALLTHROUGH */
                        case 'i':
                                switch (cflags) {
                                case PRINT_C_CHAR:
                                        value = (signed char)va_arg(args, int);
                                        break;
                                case PRINT_C_SHORT:
                                        value = (short int)va_arg(args, int);
                                        break;
                                case PRINT_C_LONG:
                                        value = va_arg(args, long int);
                                        break;
                                case PRINT_C_LLONG:
                                        value = va_arg(args, LLONG);
                                        break;
                                case PRINT_C_SIZE:
                                        value = va_arg(args, SSIZE_T);
                                        break;
                                case PRINT_C_INTMAX:
                                        value = va_arg(args, INTMAX_T);
                                        break;
                                case PRINT_C_PTRDIFF:
                                        value = va_arg(args, PTRDIFF_T);
                                        break;
                                default:
                                        value = va_arg(args, int);
                                        break;
                                }
                                fmtint(str, &len, size, value, 10, width,
                                    precision, flags);
                                break;
                        case 'X':
                                flags |= PRINT_F_UP;
                                /* FALLTHROUGH */
                        case 'x':
                                base = 16;
                                /* FALLTHROUGH */
                        case 'o':
                                if (base == 0)
                                        base = 8;
                                /* FALLTHROUGH */
                        case 'u':
                                if (base == 0)
                                        base = 10;
                                flags |= PRINT_F_UNSIGNED;
                                switch (cflags) {
                                case PRINT_C_CHAR:
                                        value = (unsigned char)va_arg(args,
                                            unsigned int);
                                        break;
                                case PRINT_C_SHORT:
                                        value = (unsigned short int)va_arg(args,
                                            unsigned int);
                                        break;
                                case PRINT_C_LONG:
                                        value = va_arg(args, unsigned long int);
                                        break;
                                case PRINT_C_LLONG:
                                        value = va_arg(args, ULLONG);
                                        break;
                                case PRINT_C_SIZE:
                                        value = va_arg(args, size_t);
                                        break;
                                case PRINT_C_INTMAX:
                                        value = va_arg(args, UINTMAX_T);
                                        break;
                                case PRINT_C_PTRDIFF:
                                        value = va_arg(args, UPTRDIFF_T);
                                        break;
                                default:
                                        value = va_arg(args, unsigned int);
                                        break;
                                }
                                fmtint(str, &len, size, value, base, width,
                                    precision, flags);
                                break;
                        case 'A':
                                /* Not yet supported, we'll use "%F". */
                                /* FALLTHROUGH */
                        case 'F':
                                flags |= PRINT_F_UP;
                        case 'a':
                                /* Not yet supported, we'll use "%f". */
                                /* FALLTHROUGH */
                        case 'f':
                                if (cflags == PRINT_C_LDOUBLE)
                                        fvalue = va_arg(args, LDOUBLE);
                                else
                                        fvalue = va_arg(args, double);
                                fmtflt(str, &len, size, fvalue, width,
                                    precision, flags, &overflow);
                                if (overflow)
                                        goto out;
                                break;
                        case 'E':
                                flags |= PRINT_F_UP;
                                /* FALLTHROUGH */
                        case 'e':
                                flags |= PRINT_F_TYPE_E;
                                if (cflags == PRINT_C_LDOUBLE)
                                        fvalue = va_arg(args, LDOUBLE);
                                else
                                        fvalue = va_arg(args, double);
                                fmtflt(str, &len, size, fvalue, width,
                                    precision, flags, &overflow);
                                if (overflow)
                                        goto out;
                                break;
                        case 'G':
                                flags |= PRINT_F_UP;
                                /* FALLTHROUGH */
                        case 'g':
                                flags |= PRINT_F_TYPE_G;
                                if (cflags == PRINT_C_LDOUBLE)
                                        fvalue = va_arg(args, LDOUBLE);
                                else
                                        fvalue = va_arg(args, double);
                                /*
                                 * If the precision is zero, it is treated as
                                 * one (cf. C99: 7.19.6.1, 8).
                                 */
                                if (precision == 0)
                                        precision = 1;
                                fmtflt(str, &len, size, fvalue, width,
                                    precision, flags, &overflow);
                                if (overflow)
                                        goto out;
                                break;
                        case 'c':
                                cvalue = (unsigned char)va_arg(args, int);
                                OUTCHAR(str, len, size, cvalue);
                                break;
                        case 's':
                                strvalue = va_arg(args, char *);
                                fmtstr(str, &len, size, strvalue, width,
                                    precision, flags);
                                break;
                        case 'p':
                                /*
                                 * C99 says: "The value of the pointer is
                                 * converted to a sequence of printing
                                 * characters, in an implementation-defined
                                 * manner." (C99: 7.19.6.1, 8)
                                 */
                                if ((strvalue = va_arg(args, void *)) == NULL)
                                        /*
                                         * We use the glibc format.  BSD prints
                                         * "0x0", SysV "0".
                                         */
                                        fmtstr(str, &len, size, "(nil)", width,
                                            -1, flags);
                                else {
                                        /*
                                         * We use the BSD/glibc format.  SysV
                                         * omits the "0x" prefix (which we emit
                                         * using the PRINT_F_NUM flag).
                                         */
                                        flags |= PRINT_F_NUM;
                                        flags |= PRINT_F_UNSIGNED;
                                        fmtint(str, &len, size,
                                            (UINTPTR_T)strvalue, 16, width,
                                            precision, flags);
                                }
                                break;
                        case 'n':
                                switch (cflags) {
                                case PRINT_C_CHAR:
                                        charptr = va_arg(args, signed char *);
                                        *charptr = (signed char)len;
                                        break;
                                case PRINT_C_SHORT:
                                        shortptr = va_arg(args, short int *);
                                        *shortptr = (short int)len;
                                        break;
                                case PRINT_C_LONG:
                                        longptr = va_arg(args, long int *);
                                        *longptr = (long int)len;
                                        break;
                                case PRINT_C_LLONG:
                                        llongptr = va_arg(args, LLONG *);
                                        *llongptr = (LLONG)len;
                                        break;
                                case PRINT_C_SIZE:
                                        /*
                                         * C99 says that with the "z" length
                                         * modifier, "a following `n' conversion
                                         * specifier applies to a pointer to a
                                         * signed integer type corresponding to
                                         * size_t argument." (7.19.6.1, 7)
                                         */
                                        sizeptr = va_arg(args, SSIZE_T *);
                                        *sizeptr = len;
                                        break;
                                case PRINT_C_INTMAX:
                                        intmaxptr = va_arg(args, INTMAX_T *);
                                        *intmaxptr = len;
                                        break;
                                case PRINT_C_PTRDIFF:
                                        ptrdiffptr = va_arg(args, PTRDIFF_T *);
                                        *ptrdiffptr = len;
                                        break;
                                default:
                                        intptr = va_arg(args, int *);
                                        *intptr = len;
                                        break;
                                }
                                break;
                        case '%':       /* Print a "%" character verbatim. */
                                OUTCHAR(str, len, size, ch);
                                break;
                        default:        /* Skip other characters. */
                                break;
                        }
                        ch = *format++;
                        state = PRINT_S_DEFAULT;
                        base = cflags = flags = width = 0;
                        precision = -1;
                        break;
                }
out:
        if (len < size)
                str[len] = '\0';
        else if (size > 0)
                str[size - 1] = '\0';

        if (overflow || len >= INT_MAX) {
                return -1;
        }
        return (int)len;
}

static void
fmtstr(char *str, size_t *len, size_t size, const char *value, int width,
       int precision, int flags)
{
        int padlen, strln;      /* Amount to pad. */
        int noprecision = (precision == -1);

        if (value == NULL)      /* We're forgiving. */
                value = "(null)";

        /* If a precision was specified, don't read the string past it. */
        for (strln = 0; value[strln] != '\0' &&
            (noprecision || strln < precision); strln++)
                continue;

        if ((padlen = width - strln) < 0)
                padlen = 0;
        if (flags & PRINT_F_MINUS)      /* Left justify. */
                padlen = -padlen;

        while (padlen > 0) {    /* Leading spaces. */
                OUTCHAR(str, *len, size, ' ');
                padlen--;
        }
        while (*value != '\0' && (noprecision || precision-- > 0)) {
                OUTCHAR(str, *len, size, *value);
                value++;
        }
        while (padlen < 0) {    /* Trailing spaces. */
                OUTCHAR(str, *len, size, ' ');
                padlen++;
        }
}

static void
fmtint(char *str, size_t *len, size_t size, INTMAX_T value, int base, int width,
       int precision, int flags)
{
        UINTMAX_T uvalue;
        char iconvert[MAX_CONVERT_LENGTH];
        char sign = 0;
        char hexprefix = 0;
        int spadlen = 0;        /* Amount to space pad. */
        int zpadlen = 0;        /* Amount to zero pad. */
        int pos;
        int separators = (flags & PRINT_F_QUOTE);
        int noprecision = (precision == -1);

        if (flags & PRINT_F_UNSIGNED)
                uvalue = value;
        else {
                uvalue = (value >= 0) ? value : -value;
                if (value < 0)
                        sign = '-';
                else if (flags & PRINT_F_PLUS)  /* Do a sign. */
                        sign = '+';
                else if (flags & PRINT_F_SPACE)
                        sign = ' ';
        }

        pos = convert(uvalue, iconvert, sizeof(iconvert), base,
            flags & PRINT_F_UP);

        if (flags & PRINT_F_NUM && uvalue != 0) {
                /*
                 * C99 says: "The result is converted to an `alternative form'.
                 * For `o' conversion, it increases the precision, if and only
                 * if necessary, to force the first digit of the result to be a
                 * zero (if the value and precision are both 0, a single 0 is
                 * printed).  For `x' (or `X') conversion, a nonzero result has
                 * `0x' (or `0X') prefixed to it." (7.19.6.1, 6)
                 */
                switch (base) {
                case 8:
                        if (precision <= pos)
                                precision = pos + 1;
                        break;
                case 16:
                        hexprefix = (flags & PRINT_F_UP) ? 'X' : 'x';
                        break;
                }
        }

        if (separators) /* Get the number of group separators we'll print. */
                separators = getnumsep(pos);

        zpadlen = precision - pos - separators;
        spadlen = width                         /* Minimum field width. */
            - separators                        /* Number of separators. */
            - MAX(precision, pos)               /* Number of integer digits. */
            - ((sign != 0) ? 1 : 0)             /* Will we print a sign? */
            - ((hexprefix != 0) ? 2 : 0);       /* Will we print a prefix? */

        if (zpadlen < 0)
                zpadlen = 0;
        if (spadlen < 0)
                spadlen = 0;

        /*
         * C99 says: "If the `0' and `-' flags both appear, the `0' flag is
         * ignored.  For `d', `i', `o', `u', `x', and `X' conversions, if a
         * precision is specified, the `0' flag is ignored." (7.19.6.1, 6)
         */
        if (flags & PRINT_F_MINUS)      /* Left justify. */
                spadlen = -spadlen;
        else if (flags & PRINT_F_ZERO && noprecision) {
                zpadlen += spadlen;
                spadlen = 0;
        }
        while (spadlen > 0) {   /* Leading spaces. */
                OUTCHAR(str, *len, size, ' ');
                spadlen--;
        }
        if (sign != 0)  /* Sign. */
                OUTCHAR(str, *len, size, sign);
        if (hexprefix != 0) {   /* A "0x" or "0X" prefix. */
                OUTCHAR(str, *len, size, '0');
                OUTCHAR(str, *len, size, hexprefix);
        }
        while (zpadlen > 0) {   /* Leading zeros. */
                OUTCHAR(str, *len, size, '0');
                zpadlen--;
        }
        while (pos > 0) {       /* The actual digits. */
                pos--;
                OUTCHAR(str, *len, size, iconvert[pos]);
                if (separators > 0 && pos > 0 && pos % 3 == 0)
                        printsep(str, len, size);
        }
        while (spadlen < 0) {   /* Trailing spaces. */
                OUTCHAR(str, *len, size, ' ');
                spadlen++;
        }
}

static void
fmtflt(char *str, size_t *len, size_t size, LDOUBLE fvalue, int width,
       int precision, int flags, int *overflow)
{
        LDOUBLE ufvalue;
        UINTMAX_T intpart;
        UINTMAX_T fracpart;
        UINTMAX_T mask;
        const char *infnan = NULL;
        char iconvert[MAX_CONVERT_LENGTH];
        char fconvert[MAX_CONVERT_LENGTH];
        char econvert[4];       /* "e-12" (without nul-termination). */
        char esign = 0;
        char sign = 0;
        int leadfraczeros = 0;
        int exponent = 0;
        int emitpoint = 0;
        int omitzeros = 0;
        int omitcount = 0;
        int padlen = 0;
        int epos = 0;
        int fpos = 0;
        int ipos = 0;
        int separators = (flags & PRINT_F_QUOTE);
        int estyle = (flags & PRINT_F_TYPE_E);
#if HAVE_LOCALECONV && HAVE_LCONV_DECIMAL_POINT
        struct lconv *lc = localeconv();
#endif  /* HAVE_LOCALECONV && HAVE_LCONV_DECIMAL_POINT */

        /*
         * AIX' man page says the default is 0, but C99 and at least Solaris'
         * and NetBSD's man pages say the default is 6, and sprintf(3) on AIX
         * defaults to 6.
         */
        if (precision == -1)
                precision = 6;

        if (fvalue < 0.0)
                sign = '-';
        else if (flags & PRINT_F_PLUS)  /* Do a sign. */
                sign = '+';
        else if (flags & PRINT_F_SPACE)
                sign = ' ';

        if (ISNAN(fvalue))
                infnan = (flags & PRINT_F_UP) ? "NAN" : "nan";
        else if (ISINF(fvalue))
                infnan = (flags & PRINT_F_UP) ? "INF" : "inf";

        if (infnan != NULL) {
                if (sign != 0)
                        iconvert[ipos++] = sign;
                while (*infnan != '\0')
                        iconvert[ipos++] = *infnan++;
                fmtstr(str, len, size, iconvert, width, ipos, flags);
                return;
        }

        /* "%e" (or "%E") or "%g" (or "%G") conversion. */
        if (flags & PRINT_F_TYPE_E || flags & PRINT_F_TYPE_G) {
                if (flags & PRINT_F_TYPE_G) {
                        /*
                         * For "%g" (and "%G") conversions, the precision
                         * specifies the number of significant digits, which
                         * includes the digits in the integer part.  The
                         * conversion will or will not be using "e-style" (like
                         * "%e" or "%E" conversions) depending on the precision
                         * and on the exponent.  However, the exponent can be
                         * affected by rounding the converted value, so we'll
                         * leave this decision for later.  Until then, we'll
                         * assume that we're going to do an "e-style" conversion
                         * (in order to get the exponent calculated).  For
                         * "e-style", the precision must be decremented by one.
                         */
                        precision--;
                        /*
                         * For "%g" (and "%G") conversions, trailing zeros are
                         * removed from the fractional portion of the result
                         * unless the "#" flag was specified.
                         */
                        if (!(flags & PRINT_F_NUM))
                                omitzeros = 1;
                }
                exponent = getexponent(fvalue);
                estyle = 1;
        }

again:
        /*
         * Sorry, we only support 9, 19, or 38 digits (that is, the number of
         * digits of the 32-bit, the 64-bit, or the 128-bit UINTMAX_MAX value
         * minus one) past the decimal point due to our conversion method.
         */
        switch (sizeof(UINTMAX_T)) {
        case 16:
                if (precision > 38)
                        precision = 38;
                break;
        case 8:
                if (precision > 19)
                        precision = 19;
                break;
        default:
                if (precision > 9)
                        precision = 9;
                break;
        }

        ufvalue = (fvalue >= 0.0) ? fvalue : -fvalue;
        if (estyle)     /* We want exactly one integer digit. */
                ufvalue /= mypow10(exponent);

        if ((intpart = cast(ufvalue)) == UINTMAX_MAX) {
                *overflow = 1;
                return;
        }

        /*
         * Factor of ten with the number of digits needed for the fractional
         * part.  For example, if the precision is 3, the mask will be 1000.
         */
#if defined(PIPE_SUBSYSTEM_WINDOWS_MINIPORT)
        mask = (unsigned long)mypow10(precision);
#else
        mask = (UINTMAX_T)mypow10(precision);
#endif
        /*
         * We "cheat" by converting the fractional part to integer by
         * multiplying by a factor of ten.
         */
        if ((fracpart = myround(mask * (ufvalue - intpart))) >= mask) {
                /*
                 * For example, ufvalue = 2.99962, intpart = 2, and mask = 1000
                 * (because precision = 3).  Now, myround(1000 * 0.99962) will
                 * return 1000.  So, the integer part must be incremented by one
                 * and the fractional part must be set to zero.
                 */
                intpart++;
                fracpart = 0;
                if (estyle && intpart == 10) {
                        /*
                         * The value was rounded up to ten, but we only want one
                         * integer digit if using "e-style".  So, the integer
                         * part must be set to one and the exponent must be
                         * incremented by one.
                         */
                        intpart = 1;
                        exponent++;
                }
        }

        /*
         * Now that we know the real exponent, we can check whether or not to
         * use "e-style" for "%g" (and "%G") conversions.  If we don't need
         * "e-style", the precision must be adjusted and the integer and
         * fractional parts must be recalculated from the original value.
         *
         * C99 says: "Let P equal the precision if nonzero, 6 if the precision
         * is omitted, or 1 if the precision is zero.  Then, if a conversion
         * with style `E' would have an exponent of X:
         *
         * - if P > X >= -4, the conversion is with style `f' (or `F') and
         *   precision P - (X + 1).
         *
         * - otherwise, the conversion is with style `e' (or `E') and precision
         *   P - 1." (7.19.6.1, 8)
         *
         * Note that we had decremented the precision by one.
         */
        if (flags & PRINT_F_TYPE_G && estyle &&
            precision + 1 > exponent && exponent >= -4) {
                precision -= exponent;
                estyle = 0;
                goto again;
        }

        if (estyle) {
                if (exponent < 0) {
                        exponent = -exponent;
                        esign = '-';
                } else
                        esign = '+';

                /*
                 * Convert the exponent.  The sizeof(econvert) is 4.  So, the
                 * econvert buffer can hold e.g. "e+99" and "e-99".  We don't
                 * support an exponent which contains more than two digits.
                 * Therefore, the following stores are safe.
                 */
                epos = convert(exponent, econvert, 2, 10, 0);
                /*
                 * C99 says: "The exponent always contains at least two digits,
                 * and only as many more digits as necessary to represent the
                 * exponent." (7.19.6.1, 8)
                 */
                if (epos == 1)
                        econvert[epos++] = '0';
                econvert[epos++] = esign;
                econvert[epos++] = (flags & PRINT_F_UP) ? 'E' : 'e';
        }

        /* Convert the integer part and the fractional part. */
        ipos = convert(intpart, iconvert, sizeof(iconvert), 10, 0);
        if (fracpart != 0)      /* convert() would return 1 if fracpart == 0. */
                fpos = convert(fracpart, fconvert, sizeof(fconvert), 10, 0);

        leadfraczeros = precision - fpos;

        if (omitzeros) {
                if (fpos > 0)   /* Omit trailing fractional part zeros. */
                        while (omitcount < fpos && fconvert[omitcount] == '0')
                                omitcount++;
                else {  /* The fractional part is zero, omit it completely. */
                        omitcount = precision;
                        leadfraczeros = 0;
                }
                precision -= omitcount;
        }

        /*
         * Print a decimal point if either the fractional part is non-zero
         * and/or the "#" flag was specified.
         */
        if (precision > 0 || flags & PRINT_F_NUM)
                emitpoint = 1;
        if (separators) /* Get the number of group separators we'll print. */
                separators = getnumsep(ipos);

        padlen = width                  /* Minimum field width. */
            - ipos                      /* Number of integer digits. */
            - epos                      /* Number of exponent characters. */
            - precision                 /* Number of fractional digits. */
            - separators                /* Number of group separators. */
            - (emitpoint ? 1 : 0)       /* Will we print a decimal point? */
            - ((sign != 0) ? 1 : 0);    /* Will we print a sign character? */

        if (padlen < 0)
                padlen = 0;

        /*
         * C99 says: "If the `0' and `-' flags both appear, the `0' flag is
         * ignored." (7.19.6.1, 6)
         */
        if (flags & PRINT_F_MINUS)      /* Left justifty. */
                padlen = -padlen;
        else if (flags & PRINT_F_ZERO && padlen > 0) {
                if (sign != 0) {        /* Sign. */
                        OUTCHAR(str, *len, size, sign);
                        sign = 0;
                }
                while (padlen > 0) {    /* Leading zeros. */
                        OUTCHAR(str, *len, size, '0');
                        padlen--;
                }
        }
        while (padlen > 0) {    /* Leading spaces. */
                OUTCHAR(str, *len, size, ' ');
                padlen--;
        }
        if (sign != 0)  /* Sign. */
                OUTCHAR(str, *len, size, sign);
        while (ipos > 0) {      /* Integer part. */
                ipos--;
                OUTCHAR(str, *len, size, iconvert[ipos]);
                if (separators > 0 && ipos > 0 && ipos % 3 == 0)
                        printsep(str, len, size);
        }
        if (emitpoint) {        /* Decimal point. */
#if HAVE_LOCALECONV && HAVE_LCONV_DECIMAL_POINT
                if (lc->decimal_point != NULL && *lc->decimal_point != '\0')
                        OUTCHAR(str, *len, size, *lc->decimal_point);
                else    /* We'll always print some decimal point character. */
#endif  /* HAVE_LOCALECONV && HAVE_LCONV_DECIMAL_POINT */
                        OUTCHAR(str, *len, size, '.');
        }
        while (leadfraczeros > 0) {     /* Leading fractional part zeros. */
                OUTCHAR(str, *len, size, '0');
                leadfraczeros--;
        }
        while (fpos > omitcount) {      /* The remaining fractional part. */
                fpos--;
                OUTCHAR(str, *len, size, fconvert[fpos]);
        }
        while (epos > 0) {      /* Exponent. */
                epos--;
                OUTCHAR(str, *len, size, econvert[epos]);
        }
        while (padlen < 0) {    /* Trailing spaces. */
                OUTCHAR(str, *len, size, ' ');
                padlen++;
        }
}

static void
printsep(char *str, size_t *len, size_t size)
{
#if HAVE_LOCALECONV && HAVE_LCONV_THOUSANDS_SEP
        struct lconv *lc = localeconv();
        int i;

        if (lc->thousands_sep != NULL)
                for (i = 0; lc->thousands_sep[i] != '\0'; i++)
                        OUTCHAR(str, *len, size, lc->thousands_sep[i]);
        else
#endif  /* HAVE_LOCALECONV && HAVE_LCONV_THOUSANDS_SEP */
                OUTCHAR(str, *len, size, ',');
}

static int
getnumsep(int digits)
{
        int separators = (digits - ((digits % 3 == 0) ? 1 : 0)) / 3;
#if HAVE_LOCALECONV && HAVE_LCONV_THOUSANDS_SEP
        int strln;
        struct lconv *lc = localeconv();

        /* We support an arbitrary separator length (including zero). */
        if (lc->thousands_sep != NULL) {
                for (strln = 0; lc->thousands_sep[strln] != '\0'; strln++)
                        continue;
                separators *= strln;
        }
#endif  /* HAVE_LOCALECONV && HAVE_LCONV_THOUSANDS_SEP */
        return separators;
}

static int
getexponent(LDOUBLE value)
{
        LDOUBLE tmp = (value >= 0.0) ? value : -value;
        int exponent = 0;

        /*
         * We check for 99 > exponent > -99 in order to work around possible
         * endless loops which could happen (at least) in the second loop (at
         * least) if we're called with an infinite value.  However, we checked
         * for infinity before calling this function using our ISINF() macro, so
         * this might be somewhat paranoid.
         */
        while (tmp < 1.0 && tmp > 0.0 && --exponent > -99)
                tmp *= 10;
        while (tmp >= 10.0 && ++exponent < 99)
                tmp /= 10;

        return exponent;
}

static int
convert(UINTMAX_T value, char *buf, size_t size, int base, int caps)
{
        const char *digits = caps ? "0123456789ABCDEF" : "0123456789abcdef";
        size_t pos = 0;

        /* We return an unterminated buffer with the digits in reverse order. */
        do {
                buf[pos++] = digits[value % base];
                value /= base;
        } while (value != 0 && pos < size);

        return (int)pos;
}

static UINTMAX_T
cast(LDOUBLE value)
{
        UINTMAX_T result;

        /*
         * We check for ">=" and not for ">" because if UINTMAX_MAX cannot be
         * represented exactly as an LDOUBLE value (but is less than LDBL_MAX),
         * it may be increased to the nearest higher representable value for the
         * comparison (cf. C99: 6.3.1.4, 2).  It might then equal the LDOUBLE
         * value although converting the latter to UINTMAX_T would overflow.
         */
        if (value >= UINTMAX_MAX)
                return UINTMAX_MAX;

#if defined(PIPE_SUBSYSTEM_WINDOWS_MINIPORT)
        result = (unsigned long)value;
#else
        result = (UINTMAX_T)value;
#endif
        /*
         * At least on NetBSD/sparc64 3.0.2 and 4.99.30, casting long double to
         * an integer type converts e.g. 1.9 to 2 instead of 1 (which violates
         * the standard).  Sigh.
         */
        return (result <= value) ? result : result - 1;
}

static UINTMAX_T
myround(LDOUBLE value)
{
        UINTMAX_T intpart = cast(value);

        return ((value -= intpart) < 0.5) ? intpart : intpart + 1;
}

static LDOUBLE
mypow10(int exponent)
{
        LDOUBLE result = 1;

        while (exponent > 0) {
                result *= 10;
                exponent--;
        }
        while (exponent < 0) {
                result /= 10;
                exponent++;
        }
        return result;
}
#endif  /* !HAVE_VSNPRINTF */

#if !HAVE_VASPRINTF
#if NEED_MYMEMCPY
void *
mymemcpy(void *dst, void *src, size_t len)
{
        const char *from = src;
        char *to = dst;

        /* No need for optimization, we use this only to replace va_copy(3). */
        while (len-- > 0)
                *to++ = *from++;
        return dst;
}
#endif  /* NEED_MYMEMCPY */

int
util_vasprintf(char **ret, const char *format, va_list ap)
{
        size_t size;
        int len;
        va_list aq;

        VA_COPY(aq, ap);
        len = vsnprintf(NULL, 0, format, aq);
        VA_END_COPY(aq);
        if (len < 0 || (*ret = malloc(size = len + 1)) == NULL)
                return -1;
        return vsnprintf(*ret, size, format, ap);
}
#endif  /* !HAVE_VASPRINTF */

#if !HAVE_SNPRINTF
#if HAVE_STDARG_H
int
util_snprintf(char *str, size_t size, const char *format, ...)
#else
int
util_snprintf(va_alist) va_dcl
#endif  /* HAVE_STDARG_H */
{
#if !HAVE_STDARG_H
        char *str;
        size_t size;
        char *format;
#endif  /* HAVE_STDARG_H */
        va_list ap;
        int len;

        VA_START(ap, format);
        VA_SHIFT(ap, str, char *);
        VA_SHIFT(ap, size, size_t);
        VA_SHIFT(ap, format, const char *);
        len = vsnprintf(str, size, format, ap);
        va_end(ap);
        return len;
}
#endif  /* !HAVE_SNPRINTF */

#if !HAVE_ASPRINTF
#if HAVE_STDARG_H
int
util_asprintf(char **ret, const char *format, ...)
#else
int
util_asprintf(va_alist) va_dcl
#endif  /* HAVE_STDARG_H */
{
#if !HAVE_STDARG_H
        char **ret;
        char *format;
#endif  /* HAVE_STDARG_H */
        va_list ap;
        int len;

        VA_START(ap, format);
        VA_SHIFT(ap, ret, char **);
        VA_SHIFT(ap, format, const char *);
        len = vasprintf(ret, format, ap);
        va_end(ap);
        return len;
}
#endif  /* !HAVE_ASPRINTF */
#else   /* Dummy declaration to avoid empty translation unit warnings. */
int main(void);
#endif  /* !HAVE_SNPRINTF || !HAVE_VSNPRINTF || !HAVE_ASPRINTF || [...] */


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