treewide: Move device_tree to commonlib

[coreboot2.git] / payloads / libpayload / libc / printf.c

/*
 *
 * It has originally been taken from the HelenOS project
 * (http://www.helenos.eu), and slightly modified for our purposes.
 *
 * Copyright (C) 2001-2004 Jakub Jermar
 * Copyright (C) 2006 Josef Cejka
 * Copyright (C) 2008 Uwe Hermann <uwe@hermann-uwe.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#include <libpayload.h>
#include <ctype.h>

static struct _FILE {
} _stdout, _stdin, _stderr;

FILE *stdout = &_stdout;
FILE *stdin = &_stdin;
FILE *stderr = &_stderr;

/** Structure for specifying output methods for different printf clones. */
struct printf_spec {
        /* Output function, returns count of printed characters or EOF. */
        int (*write) (const char *, size_t, void *);
        /* Support data - output stream specification, its state, locks, ... */
        void *data;
};

/** Show prefixes 0x or 0. */
#define __PRINTF_FLAG_PREFIX            0x00000001
/** Signed / unsigned number. */
#define __PRINTF_FLAG_SIGNED            0x00000002
/** Print leading zeroes. */
#define __PRINTF_FLAG_ZEROPADDED        0x00000004
/** Align to left. */
#define __PRINTF_FLAG_LEFTALIGNED       0x00000010
/** Always show + sign. */
#define __PRINTF_FLAG_SHOWPLUS          0x00000020
/** Print space instead of plus. */
#define __PRINTF_FLAG_SPACESIGN         0x00000040
/** Show big characters. */
#define __PRINTF_FLAG_BIGCHARS          0x00000080
/** Number has - sign. */
#define __PRINTF_FLAG_NEGATIVE          0x00000100

/**
 * Buffer big enough for 64-bit number printed in base 2, sign, and prefix.
 * Add some more to support sane amounts of zero-padding.
 */
#define PRINT_BUFFER_SIZE               (64 + 1 + 2 + 13)

/** Enumeration of possible arguments types. */
typedef enum {
        PrintfQualifierByte = 0,
        PrintfQualifierShort,
        PrintfQualifierInt,
        PrintfQualifierLong,
        PrintfQualifierLongLong,
        PrintfQualifierPointer,
} qualifier_t;

static const char digits_small[] = "0123456789abcdef";
static const char digits_big[] = "0123456789ABCDEF";

/**
 * Print one or more characters without adding newline.
 *
 * @param buf   Buffer of >= count bytesi size. NULL pointer is not allowed!
 * @param count Number of characters to print.
 * @param ps    Output method and its data.
 * @return      Number of characters printed.
 */
static int printf_putnchars(const char *buf, size_t count,
                            struct printf_spec *ps)
{
        return ps->write(buf, count, ps->data);
}

/**
 * Print a string without adding a newline.
 *
 * @param str   String to print.
 * @param ps    Write function specification and support data.
 * @return      Number of characters printed.
 */
static inline int printf_putstr(const char *str, struct printf_spec *ps)
{
        return printf_putnchars(str, strlen(str), ps);
}

/**
 * Print one character.
 *
 * @param c     Character to be printed.
 * @param ps    Output method.
 * @return      Number of characters printed.
 */
static int printf_putchar(int c, struct printf_spec *ps)
{
        char ch = c;

        return ps->write(&ch, 1, ps->data);
}

/* Print spaces for padding. Ignores negative counts. */
static int print_spaces(int count, struct printf_spec *ps)
{
        int tmp, ret;
        char buffer[PRINT_BUFFER_SIZE];

        if (count <= 0)
                return 0;

        memset(buffer, ' ', MIN(PRINT_BUFFER_SIZE, count));
        for (tmp = count; tmp > PRINT_BUFFER_SIZE; tmp -= PRINT_BUFFER_SIZE)
                if ((ret = printf_putnchars(buffer, PRINT_BUFFER_SIZE, ps)) < 0)
                        return ret;

        if ((ret = printf_putnchars(buffer, tmp, ps)) < 0)
                return ret;

        return count;
}

/**
 * Print one formatted character.
 *
 * @param c     Character to print.
 * @param width Width modifier.
 * @param flags Flags that change the way the character is printed.
 * @param ps    Output methods spec for different printf clones.
 * @return      Number of characters printed, negative value on failure.
 */
static int print_char(char c, int width, uint64_t flags, struct printf_spec *ps)
{
        int retval;
        int counter = 1;

        if (!(flags & __PRINTF_FLAG_LEFTALIGNED)) {
                if ((retval = print_spaces(width - 1, ps)) < 0)
                        return retval;
                else
                        counter += retval;
        }

        if ((retval = printf_putchar(c, ps)) < 0)
                return retval;

        if (flags & __PRINTF_FLAG_LEFTALIGNED) {
                if ((retval = print_spaces(width - 1, ps)) < 0)
                        return retval;
                else
                        counter += retval;
        }

        return counter;
}

/**
 * Print string.
 *
 * @param s             String to be printed.
 * @param width         Width modifier.
 * @param precision     Precision modifier.
 * @param flags         Flags that modify the way the string is printed.
 * @param ps            Output methods spec for different printf clones.
 * @return              Number of characters printed, negative value on failure.
 */
/** Structure for specifying output methods for different printf clones. */
static int print_string(char *s, int width, unsigned int precision,
                        uint64_t flags, struct printf_spec *ps)
{
        int counter = 0, retval;
        size_t size;

        if (s == NULL)
                return printf_putstr("(NULL)", ps);
        size = strlen(s);
        /* Print leading spaces. */
        if (precision == 0)
                precision = size;
        width -= precision;

        if (!(flags & __PRINTF_FLAG_LEFTALIGNED)) {
                if ((retval = print_spaces(width, ps)) < 0)
                        return retval;
                else
                        counter += retval;
        }

        if ((retval = printf_putnchars(s, MIN(size, precision), ps)) < 0)
                return retval;
        counter += retval;

        if (flags & __PRINTF_FLAG_LEFTALIGNED) {
                if ((retval = print_spaces(width, ps)) < 0)
                        return retval;
                else
                        counter += retval;
        }

        return counter;
}

/**
 * Print a number in a given base.
 *
 * Print significant digits of a number in given base.
 *
 * @param num           Number to print.
 * @param width         Width modifier.
 * @param precision     Precision modifier.
 * @param base          Base to print the number in (must be between 2 and 16).
 * @param flags         Flags that modify the way the number is printed.
 * @param ps            Output methods spec for different printf clones.
 * @return              Number of characters printed.
 */
static int print_number(uint64_t num, int width, int precision, int base,
                        uint64_t flags, struct printf_spec *ps)
{
        const char *digits = digits_small;
        char d[PRINT_BUFFER_SIZE];
        char *ptr = &d[PRINT_BUFFER_SIZE];
        int size = 0;                   /* Size of the string in ptr */
        int counter = 0;                /* Amount of actually printed bytes. */
        char sgn;
        int retval;

        if (flags & __PRINTF_FLAG_BIGCHARS)
                digits = digits_big;

        if (num == 0) {
                *--ptr = '0';
                size++;
        } else {
                do {
                        *--ptr = digits[num % base];
                        size++;
                } while (num /= base);
        }

        /* Both precision and LEFTALIGNED overrule ZEROPADDED. */
        if ((flags & __PRINTF_FLAG_LEFTALIGNED) || precision)
                flags &= ~__PRINTF_FLAG_ZEROPADDED;

        /* Fix precision now since it doesn't count prefixes/signs. */
        precision -= size;

        /* Reserve size for prefixes/signs before filling up padding. */
        sgn = 0;
        if (flags & __PRINTF_FLAG_SIGNED) {
                if (flags & __PRINTF_FLAG_NEGATIVE) {
                        sgn = '-';
                        size++;
                } else if (flags & __PRINTF_FLAG_SHOWPLUS) {
                        sgn = '+';
                        size++;
                } else if (flags & __PRINTF_FLAG_SPACESIGN) {
                        sgn = ' ';
                        size++;
                }
        }
        if (flags & __PRINTF_FLAG_PREFIX) {
                switch (base) {
                case 2: /* Binary formating is not standard, but useful. */
                        size += 2;
                        break;
                case 8:
                        size++;
                        break;
                case 16:
                        size += 2;
                        break;
                }
        }

        /* If this is still set we didn't have a precision, so repurpose it */
        if (flags & __PRINTF_FLAG_ZEROPADDED)
                precision = width - size;

        /* Pad smaller numbers with 0 (larger numbers lead to precision < 0). */
        if (precision > 0) {
                precision = MIN(precision, PRINT_BUFFER_SIZE - size);
                ptr -= precision;
                size += precision;
                memset(ptr, '0', precision);
        }

        /* Add sign and prefix (we adjusted size for this beforehand). */
        if (flags & __PRINTF_FLAG_PREFIX) {
                switch (base) {
                case 2: /* Binary formating is not standard, but useful. */
                        *--ptr = (flags & __PRINTF_FLAG_BIGCHARS) ? 'B' : 'b';
                        *--ptr = '0';
                        break;
                case 8:
                        *--ptr = '0';
                        break;
                case 16:
                        *--ptr = (flags & __PRINTF_FLAG_BIGCHARS) ? 'X' : 'x';
                        *--ptr = '0';
                        break;
                }
        }
        if (sgn)
                *--ptr = sgn;

        /* Pad with spaces up to width, try to avoid extra putnchar if we can */
        width -= size;
        if (width > 0 && !(flags & __PRINTF_FLAG_LEFTALIGNED)) {
                int tmp = MIN(width, PRINT_BUFFER_SIZE - size);
                ptr -= tmp;
                size += tmp;
                memset(ptr, ' ', tmp);
                if ((retval = print_spaces(width - tmp, ps)) < 0)
                        return retval;
                else
                        counter += retval;
        }

        /* Now print the whole thing at once. */
        if ((retval = printf_putnchars(ptr, size, ps)) < 0)
                return retval;
        counter += retval;

        /* Edge case: left-aligned with width (should be rare). */
        if (flags & __PRINTF_FLAG_LEFTALIGNED) {
                if ((retval = print_spaces(width, ps)) < 0)
                        return retval;
                else
                        counter += retval;
        }

        return counter;
}

/**
 * Print formatted string.
 *
 * Print string formatted according to the fmt parameter and variadic arguments.
 * Each formatting directive must have the following form:
 *
 *      \% [ FLAGS ] [ WIDTH ] [ .PRECISION ] [ TYPE ] CONVERSION
 *
 * FLAGS:@n
 *      - "#"   Force to print prefix.For \%o conversion, the prefix is 0, for
 *              \%x and \%X prefixes are 0x and 0X and for conversion \%b the
 *              prefix is 0b.
 *
 *      - "-"   Align to left.
 *
 *      - "+"   Print positive sign just as negative.
 *
 *      - " "   If the printed number is positive and "+" flag is not set,
 *              print space in place of sign.
 *
 *      - "0"   Print 0 as padding instead of spaces. Zeroes are placed between
 *              sign and the rest of the number. This flag is ignored if "-"
 *              flag is specified.
 *
 * WIDTH:@n
 *      - Specify the minimal width of a printed argument. If it is bigger,
 *      width is ignored. If width is specified with a "*" character instead of
 *      number, width is taken from parameter list. And integer parameter is
 *      expected before parameter for processed conversion specification. If
 *      this value is negative its absolute value is taken and the "-" flag is
 *      set.
 *
 * PRECISION:@n
 *      - Value precision. For numbers it specifies minimum valid numbers.
 *      Smaller numbers are printed with leading zeroes. Bigger numbers are not
 *      affected. Strings with more than precision characters are cut off. Just
 *      as with width, an "*" can be used used instead of a number. An integer
 *      value is then expected in parameters. When both width and precision are
 *      specified using "*", the first parameter is used for width and the
 *      second one for precision.
 *
 * TYPE:@n
 *      - "hh"  Signed or unsigned char.@n
 *      - "h"   Signed or unsigned short.@n
 *      - ""    Signed or unsigned int (default value).@n
 *      - "l"   Signed or unsigned long int.@n
 *      - "ll"  Signed or unsigned long long int.@n
 *
 *
 * CONVERSION:@n
 *      - %     Print percentile character itself.
 *
 *      - c     Print single character.
 *
 *      - s     Print zero terminated string. If a NULL value is passed as
 *              value, "(NULL)" is printed instead.
 *
 *      - P, p  Print value of a pointer. Void * value is expected and it is
 *              printed in hexadecimal notation with prefix (as with \%#X / \%#x
 *              for 32-bit or \%#X / \%#x for 64-bit long pointers).
 *
 *      - b     Print value as unsigned binary number. Prefix is not printed by
 *              default. (Nonstandard extension.)
 *
 *      - o     Print value as unsigned octal number. Prefix is not printed by
 *              default.
 *
 *      - d, i  Print signed decimal number. There is no difference between d
 *              and i conversion.
 *
 *      - u     Print unsigned decimal number.
 *
 *      - X, x  Print hexadecimal number with upper- or lower-case. Prefix is
 *              not printed by default.
 *
 * All other characters from fmt except the formatting directives are printed in
 * verbatim.
 *
 * @param fmt   Formatting NULL terminated string.
 * @param ps    TODO.
 * @param ap    TODO.
 * @return      Number of characters printed, negative value on failure.
 */
static int printf_core(const char *fmt, struct printf_spec *ps, va_list ap)
{
        int i = 0;              /* Index of the currently processed char from fmt */
        int j = 0;              /* Index to the first not printed nonformating character */
        int end;
        int counter;            /* Counter of printed characters */
        int retval;             /* Used to store return values from called functions */
        char c;
        qualifier_t qualifier;  /* Type of argument */
        int base;               /* Base in which a numeric parameter will be printed */
        uint64_t number;        /* Argument value */
        size_t size;            /* Byte size of integer parameter */
        int width, precision;
        uint64_t flags;

        counter = 0;

        while ((c = fmt[i])) {
                /* Control character. */
                if (c == '%') {
                        /* Print common characters if any processed. */
                        if (i > j) {
                                if ((retval = printf_putnchars(&fmt[j],
                                    (size_t) (i - j), ps)) < 0)
                                        return retval;
                                counter += retval;
                        }

                        j = i;
                        /* Parse modifiers. */
                        flags = 0;
                        end = 0;

                        do {
                                ++i;
                                switch (c = fmt[i]) {
                                case '#':
                                        flags |= __PRINTF_FLAG_PREFIX;
                                        break;
                                case '-':
                                        flags |= __PRINTF_FLAG_LEFTALIGNED;
                                        break;
                                case '+':
                                        flags |= __PRINTF_FLAG_SHOWPLUS;
                                        break;
                                case ' ':
                                        flags |= __PRINTF_FLAG_SPACESIGN;
                                        break;
                                case '0':
                                        flags |= __PRINTF_FLAG_ZEROPADDED;
                                        break;
                                default:
                                        end = 1;
                                };

                        } while (end == 0);

                        /* Width & '*' operator. */
                        width = 0;
                        if (isdigit(fmt[i])) {
                                while (isdigit(fmt[i])) {
                                        width *= 10;
                                        width += fmt[i++] - '0';
                                }
                        } else if (fmt[i] == '*') {
                                /* Get width value from argument list. */
                                i++;
                                width = (int)va_arg(ap, int);
                                if (width < 0) {
                                        /* Negative width sets '-' flag. */
                                        width *= -1;
                                        flags |= __PRINTF_FLAG_LEFTALIGNED;
                                }
                        }

                        /* Precision and '*' operator. */
                        precision = 0;
                        if (fmt[i] == '.') {
                                ++i;
                                if (isdigit(fmt[i])) {
                                        while (isdigit(fmt[i])) {
                                                precision *= 10;
                                                precision += fmt[i++] - '0';
                                        }
                                } else if (fmt[i] == '*') {
                                        /* Get precision from argument list. */
                                        i++;
                                        precision = (int)va_arg(ap, int);
                                        /* Ignore negative precision. */
                                        if (precision < 0)
                                                precision = 0;
                                }
                        }

                        switch (fmt[i++]) {
                        /** @todo unimplemented qualifiers:
                         * t ptrdiff_t - ISO C 99
                         */
                        case 'h':       /* char or short */
                                qualifier = PrintfQualifierShort;
                                if (fmt[i] == 'h') {
                                        i++;
                                        qualifier = PrintfQualifierByte;
                                }
                                break;
                        case 'z':       /* size_t or ssize_t */
                                qualifier = PrintfQualifierLong;
                                break;
                        case 'l':       /* long or long long */
                                qualifier = PrintfQualifierLong;
                                if (fmt[i] == 'l') {
                                        i++;
                                        qualifier = PrintfQualifierLongLong;
                                }
                                break;
                        default:
                                /* default type */
                                qualifier = PrintfQualifierInt;
                                --i;
                        }

                        base = 10;

                        switch (c = fmt[i]) {
                        /* String and character conversions */
                        case 's':
                                if ((retval = print_string(va_arg(ap, char *),
                                    width, precision, flags, ps)) < 0)
                                        return retval;
                                counter += retval;
                                j = i + 1;
                                goto next_char;
                        case 'c':
                                c = va_arg(ap, unsigned int);
                                if ((retval = print_char(c, width, flags, ps)) < 0)
                                        return retval;
                                counter += retval;
                                j = i + 1;
                                goto next_char;

                        /* Integer values */
                        case 'P':       /* pointer */
                                flags |= __PRINTF_FLAG_BIGCHARS;
                                __fallthrough;
                        case 'p':
                                flags |= __PRINTF_FLAG_PREFIX;
                                base = 16;
                                qualifier = PrintfQualifierPointer;
                                break;
                        case 'b':
                                base = 2;
                                break;
                        case 'o':
                                base = 8;
                                break;
                        case 'd':
                        case 'i':
                                flags |= __PRINTF_FLAG_SIGNED;
                                break;
                        case 'u':
                                break;
                        case 'X':
                                flags |= __PRINTF_FLAG_BIGCHARS;
                                __fallthrough;
                        case 'x':
                                base = 16;
                                break;
                        case '%': /* percentile itself */
                                j = i;
                                goto next_char;
                        default: /* Bad formatting */
                                /*
                                 * Unknown format. Now, j is the index of '%'
                                 * so we will print whole bad format sequence.
                                 */
                                goto next_char;
                        }

                        /* Print integers. */
                        /* Print number. */
                        switch (qualifier) {
                        case PrintfQualifierByte:
                                size = sizeof(unsigned char);
                                number = (uint64_t) va_arg(ap, unsigned int);
                                break;
                        case PrintfQualifierShort:
                                size = sizeof(unsigned short);
                                number = (uint64_t) va_arg(ap, unsigned int);
                                break;
                        case PrintfQualifierInt:
                                size = sizeof(unsigned int);
                                number = (uint64_t) va_arg(ap, unsigned int);
                                break;
                        case PrintfQualifierLong:
                                size = sizeof(unsigned long);
                                number = (uint64_t) va_arg(ap, unsigned long);
                                break;
                        case PrintfQualifierLongLong:
                                size = sizeof(unsigned long long);
                                number = (uint64_t) va_arg(ap, unsigned long long);
                                break;
                        case PrintfQualifierPointer:
                                size = sizeof(void *);
                                number = (uint64_t) (unsigned long)va_arg(ap, void *);
                                break;
                        }

                        if (flags & __PRINTF_FLAG_SIGNED) {
                                if (number & (0x1ULL << (size * 8 - 1))) {
                                        flags |= __PRINTF_FLAG_NEGATIVE;

                                        if (size == sizeof(uint64_t)) {
                                                number = -((int64_t) number);
                                        } else {
                                                number = ~number;
                                                number &= ~(0xFFFFFFFFFFFFFFFFll << (size * 8));
                                                number++;
                                        }
                                }
                        }

                        if ((retval = print_number(number, width, precision,
                                                   base, flags, ps)) < 0)
                                return retval;

                        counter += retval;
                        j = i + 1;
                }
next_char:
                ++i;
        }

        if (i > j) {
                if ((retval = printf_putnchars(&fmt[j],
                    (u64) (i - j), ps)) < 0)
                        return retval;
                counter += retval;
        }

        return counter;
}

int snprintf(char *str, size_t size, const char *fmt, ...)
{
        int ret;
        va_list args;

        va_start(args, fmt);
        ret = vsnprintf(str, size, fmt, args);
        va_end(args);

        return ret;
}

int sprintf(char *str, const char *fmt, ...)
{
        int ret;
        va_list args;

        va_start(args, fmt);
        ret = vsprintf(str, fmt, args);
        va_end(args);

        return ret;
}

int fprintf(FILE *file, const char *fmt, ...)
{
        int ret;
        if ((file == stdout) || (file == stderr)) {
                va_list args;
                va_start(args, fmt);
                ret = vprintf(fmt, args);
                va_end(args);

                return ret;
        }
        return -1;
}

struct vsnprintf_data {
        size_t size;            /* Total space for string */
        size_t len;             /* Count of currently used characters */
        char *string;           /* Destination string */
};

/**
 * Write string to given buffer.
 *
 * Write at most data->size characters including trailing zero. According to
 * C99, snprintf() has to return number of characters that would have been
 * written if enough space had been available. Hence the return value is not
 * number of really printed characters but size of the input string.
 * Number of really used characters is stored in data->len.
 *
 * @param str   Source string to print.
 * @param count Size of source string.
 * @param _data Structure with destination string, counter of used space
 *              and total string size.
 * @return Number of characters to print (not characters really printed!).
 */
static int vsnprintf_write(const char *str, size_t count, void *_data)
{
        struct vsnprintf_data *data = _data;
        size_t i;

        i = data->size - data->len;
        if (i == 0)
                return count;

        /* We have only one free byte left in buffer => write trailing zero. */
        if (i == 1) {
                data->string[data->size - 1] = 0;
                data->len = data->size;
                return count;
        }

        /*
         * We have not enough space for whole string with the trailing
         * zero => print only a part of string.
         */
        if (i <= count) {
                memcpy((void *)(data->string + data->len), (void *)str, i - 1);
                data->string[data->size - 1] = 0;
                data->len = data->size;
                return count;
        }

        /* Buffer is big enough to print whole string. */
        memcpy((void *)(data->string + data->len), (void *)str, count);
        data->len += count;
        /*
         * Put trailing zero at end, but not count it into data->len so
         * it could be rewritten next time.
         */
        data->string[data->len] = 0;

        return count;
}

int vsnprintf(char *str, size_t size, const char *fmt, va_list ap)
{
        struct vsnprintf_data data = { size, 0, str };
        struct printf_spec ps = { vsnprintf_write, &data };

        /* Print 0 at end of string - fix case that nothing will be printed. */
        if (size > 0)
                str[0] = 0;

        /* vsnprintf_write() ensures that str will be terminated by zero. */
        return printf_core(fmt, &ps, ap);
}

int vsprintf(char *str, const char *fmt, va_list ap)
{
        return vsnprintf(str, (size_t) - 1, fmt, ap);
}

int printf(const char *fmt, ...)
{
        int ret;
        va_list args;

        va_start(args, fmt);
        ret = vprintf(fmt, args);
        va_end(args);

        return ret;
}

static int vprintf_write(const char *str, size_t count, void *unused)
{
        console_write(str, count);
        return count;
}

int vprintf(const char *fmt, va_list ap)
{
        struct printf_spec ps = { vprintf_write, NULL };

        return printf_core(fmt, &ps, ap);
}