ee_printf.c

/* 
 * Copyright (c) 2015-2017 Contributors as noted in the AUTHORS file
 *
 * This file is part of Solo5, a unikernel base layer.
 *
 * Permission to use, copy, modify, and/or distribute this software
 * for any purpose with or without fee is hereby granted, provided
 * that the above copyright notice and this permission notice appear
 * in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
 * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/* This code is based on a file that contains the following:
 *
 * Copyright (C) 2002 Michael Ringgaard. All rights reserved.
 *
 * 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 project 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 COPYRIGHT HOLDERS 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
 * COPYRIGHT OWNER 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.
 *
 */
#include "kernel.h"

#undef HAS_FLOAT
#define ZEROPAD  (1<<0)/* Pad with zero */
#define SIGN    (1<<1)/* Unsigned/signed long */
#define PLUS    (1<<2)/* Show plus */
#define SPACE   (1<<3)/* Spacer */
#define LEFT    (1<<4)/* Left justified */
#define HEX_PREP (1<<5)/* 0x */
#define UPPERCASE   (1<<6)/* 'ABCDEF' */

#define is_digit(c) ((c) >= '0' && (c) <= '9')

struct outbuf {
    int size;
    char *ptr;
    int num_printed;
};
static void fill_outbuf(struct outbuf *o, char c)
{
    if (o->num_printed++ < o->size)
        *o->ptr++ = c;
}
static char *lower_digits = "0123456789abcdefghijklmnopqrstuvwxyz";
static char *upper_digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
static size_t strnlen(const char *s, size_t count);

static size_t strnlen(const char *s, size_t count)
{
    const char *sc;

    for (sc = s; *sc != '\0' && count--; ++sc)
        ;
    return sc - s;
}

static int ee_skip_atoi(const char **s)
{
    int i = 0;

    while (is_digit(**s))
        i = i*10 + *((*s)++) - '0';
    return i;
}

static void out_number(struct outbuf *out, long num, int base, int size,
                       int precision, int type){
    char c, sign, tmp[66];
    char *dig = lower_digits;
    int i;

    if (type & UPPERCASE)
        dig = upper_digits;
    if (type & LEFT)
        type &= ~ZEROPAD;
    if (base < 2 || base > 36)
        return;

    c = (type & ZEROPAD) ? '0' : ' ';
    sign = 0;
    if (type & SIGN) {
        if (num < 0) {
            sign = '-';
            num = -num;
            size--;
        } else if (type & PLUS) {
            sign = '+';
            size--;
        } else if (type & SPACE) {
            sign = ' ';
            size--;
        }
    }

    if (type & HEX_PREP) {
        if (base == 16)
            size -= 2;
        else if (base == 8)
            size--;
    }

    i = 0;

    if (num == 0) {
        tmp[i++] = '0';
    } else {
        while (num != 0) {
            tmp[i++] = dig[((unsigned long) num) % (unsigned int) base];
            num = ((unsigned long) num) / (unsigned int) base;
        }
    }

    if (i > precision)
        precision = i;
    size -= precision;
    if (!(type & (ZEROPAD | LEFT)))
        while (size-- > 0)
            fill_outbuf(out, ' ');
    if (sign)
        fill_outbuf(out, sign);

    if (type & HEX_PREP) {
        if (base == 8) {
            fill_outbuf(out, '0');
        } else if (base == 16) {
            fill_outbuf(out, '0');
            fill_outbuf(out, lower_digits[33]);
        }
    }

    if (!(type & LEFT))
        while (size-- > 0)
            fill_outbuf(out, c);

    while (i < precision--)
        fill_outbuf(out, '0');
    while (i-- > 0)
        fill_outbuf(out, tmp[i]);
    while (size-- > 0)
        fill_outbuf(out, ' ');
}

static void out_eaddr(struct outbuf *out, unsigned char *addr, int size,
                      __attribute__((unused)) int precision, int type)
{
    char tmp[24];
    char *dig = lower_digits;
    int i, len;

    if (type & UPPERCASE)
        dig = upper_digits;
    len = 0;
    for (i = 0; i < 6; i++) {
        if (i != 0)
            tmp[len++] = ':';
        tmp[len++] = dig[addr[i] >> 4];
        tmp[len++] = dig[addr[i] & 0x0F];
    }

    if (!(type & LEFT))
        while (len < size--)
            fill_outbuf(out, ' ');

    for (i = 0; i < len; ++i)
        fill_outbuf(out, tmp[i]);

    while (len < size--)
        fill_outbuf(out, ' ');
}

static void out_iaddr(struct outbuf *out, unsigned char *addr, int size,
                      __attribute__((unused)) int precision, int type)
{
    char tmp[24];
    int i, n, len;

    len = 0;
    for (i = 0; i < 4; i++) {
        if (i != 0)
            tmp[len++] = '.';
        n = addr[i];

        if (n == 0) {
            tmp[len++] = lower_digits[0];
        } else {
            if (n >= 100) {
                tmp[len++] = lower_digits[n / 100];
                n = n % 100;
                tmp[len++] = lower_digits[n / 10];
                n = n % 10;
            } else if (n >= 10) {
                tmp[len++] = lower_digits[n / 10];
                n = n % 10;
            }

            tmp[len++] = lower_digits[n];
        }
    }

    if (!(type & LEFT))
        while (len < size--)
            fill_outbuf(out, ' ');

    for (i = 0; i < len; ++i)
        fill_outbuf(out, tmp[i]);

    while (len < size--)
        fill_outbuf(out, ' ');
}



#ifdef HAS_FLOAT

char *ecvtbuf(double arg, int ndigits, int *decpt, int *sign, char *buf);
char *fcvtbuf(double arg, int ndigits, int *decpt, int *sign, char *buf);
static void ee_bufcpy(char *d, char *s, int count);

void ee_bufcpy(char *pd, char *ps, int count)
{
    char *pe = ps + count;

    while (ps != pe)
        *pd++ = *ps++;
}

static void parse_float(double value, char *buffer, char fmt, int precision)
{
    int decpt, sign, exp, pos;
    char *fdigits = NULL;
    char cvtbuf[80];
    int capexp = 0;
    int magnitude;

    if (fmt == 'G' || fmt == 'E') {
        capexp = 1;
        fmt += 'a' - 'A';
    }

    if (fmt == 'g') {
        fdigits = ecvtbuf(value, precision, &decpt, &sign, cvtbuf);
        magnitude = decpt - 1;
        if (magnitude < -4  ||  magnitude > precision - 1) {
            fmt = 'e';
            precision -= 1;
        } else {
            fmt = 'f';
            precision -= decpt;
        }
    }

    if (fmt == 'e') {
        fdigits = ecvtbuf(value, precision + 1, &decpt, &sign, cvtbuf);

        if (sign)
            *buffer++ = '-';
        *buffer++ = *fdigits;
        if (precision > 0)
            *buffer++ = '.';
        ee_bufcpy(buffer, fdigits + 1, precision);
        buffer += precision;
        *buffer++ = capexp ? 'E' : 'e';

        if (decpt == 0) {
            if (value == 0.0)
                exp = 0;
            else
                exp = -1;
        } else
            exp = decpt - 1;

        if (exp < 0) {
            *buffer++ = '-';
            exp = -exp;
        } else
            *buffer++ = '+';

        buffer[2] = (exp % 10) + '0';
        exp = exp / 10;
        buffer[1] = (exp % 10) + '0';
        exp = exp / 10;
        buffer[0] = (exp % 10) + '0';
        buffer += 3;
    } else if (fmt == 'f') {
        fdigits = fcvtbuf(value, precision, &decpt, &sign, cvtbuf);
        if (sign)
            *buffer++ = '-';
        if (*fdigits) {
            if (decpt <= 0) {
                *buffer++ = '0';
                *buffer++ = '.';
                for (pos = 0; pos < -decpt; pos++)
                    *buffer++ = '0';
                while (*fdigits)
                    *buffer++ = *fdigits++;
            } else {
                pos = 0;
                while (*fdigits) {
                    if (pos++ == decpt)
                        *buffer++ = '.';
                    *buffer++ = *fdigits++;
                }
            }
        } else {
            *buffer++ = '0';
            if (precision > 0) {
                *buffer++ = '.';
                for (pos = 0; pos < precision; pos++)
                    *buffer++ = '0';
            }
        }
    }

    *buffer = '\0';
}

static void decimal_point(char *buffer)
{
    while (*buffer) {
        if (*buffer == '.')
            return;
        if (*buffer == 'e' || *buffer == 'E')
            break;
        buffer++;
    }

    if (*buffer) {
        int n = strnlen(buffer, 256);

        while (n > 0) {
            buffer[n + 1] = buffer[n];
            n--;
        }

        *buffer = '.';
    } else {
        *buffer++ = '.';
        *buffer = '\0';
    }
}

static void cropzeros(char *buffer)
{
    char *stop;

    while (*buffer && *buffer != '.')
        buffer++;
    if (*buffer++) {
        while (*buffer && *buffer != 'e' && *buffer != 'E')
            buffer++;
        stop = buffer--;
        while (*buffer == '0')
            buffer--;
        if (*buffer == '.')
            buffer--;
        while (buffer != stop)
            *++buffer = 0;
    }
}

static char *flt(char *str, double num, int size, int precision,
                 char fmt, int flags)
{
    char tmp[80];
    char c, sign;
    int n, i;

    /* Left align means no zero padding */
    if (flags & LEFT)
        flags &= ~ZEROPAD;

    /* Determine padding and sign char */
    c = (flags & ZEROPAD) ? '0' : ' ';
    sign = 0;
    if (flags & SIGN) {
        if (num < 0.0) {
            sign = '-';
            num = -num;
            size--;
        } else if (flags & PLUS) {
            sign = '+';
            size--;
        } else if (flags & SPACE) {
            sign = ' ';
            size--;
        }
    }

    /* Compute the precision value */
    if (precision < 0)
        precision = 6; /* Default precision: 6 */

    /* Convert floating point number to text */
    parse_float(num, tmp, fmt, precision);

    if ((flags & HEX_PREP) && precision == 0)
        decimal_point(tmp);
    if (fmt == 'g' && !(flags & HEX_PREP))
        cropzeros(tmp);

    n = strnlen(tmp, 256);

    /* Output number with alignment and padding */
    size -= n;
    if (!(flags & (ZEROPAD | LEFT)))
        while (size-- > 0)
            *str++ = ' ';
    if (sign)
        *str++ = sign;
    if (!(flags & LEFT))
        while (size-- > 0)
            *str++ = c;
    for (i = 0; i < n; i++)
        *str++ = tmp[i];
    while (size-- > 0)
        *str++ = ' ';

    return str;
}

static void out_flt(struct outbuf *out, double num, int size, int precision,
                    char fmt, int flags)
{
    char tmp[80];
    char c, sign;
    int n, i;

    /* Left align means no zero padding */
    if (flags & LEFT)
        flags &= ~ZEROPAD;

    /* Determine padding and sign char */
    c = (flags & ZEROPAD) ? '0' : ' ';
    sign = 0;
    if (flags & SIGN) {
        if (num < 0.0) {
            sign = '-';
            num = -num;
            size--;
        } else if (flags & PLUS) {
            sign = '+';
            size--;
        } else if (flags & SPACE) {
            sign = ' ';
            size--;
        }
    }

    /* Compute the precision value */
    if (precision < 0)
        precision = 6; /* Default precision: 6 */

    /* Convert floating point number to text */
    parse_float(num, tmp, fmt, precision);

    if ((flags & HEX_PREP) && precision == 0)
        decimal_point(tmp);
    if (fmt == 'g' && !(flags & HEX_PREP))
        cropzeros(tmp);

    n = strnlen(tmp, 256);

    /* Output number with alignment and padding */
    size -= n;

    if (!(flags & (ZEROPAD | LEFT)))
        while (size-- > 0)
            fill_outbuf(out, ' ');

    if (sign)
        fill_outbuf(out, sign);

    if (!(flags & LEFT))
        while (size-- > 0)
            fill_outbuf(out, c);

    for (i = 0; i < n; i++)
        fill_outbuf(out, tmp[i]);

    while (size-- > 0)
        fill_outbuf(out, ' ');
}
#endif

int vsnprintf(char *buf, size_t size,
              const char *fmt, va_list args)
{
    int len;
    unsigned long num;
    int i, base;
    char *s;

    int flags;            /* Flags to number() */

    int field_width;      /* Width of output field */
    int precision;        /* Min. # of digits for integers,      */
                          /* max number of chars for from string */
    int qualifier;        /* 'h', 'l', or 'L' for integer fields */
    struct outbuf out;

    out.size = size;
    out.ptr = buf;
    out.num_printed = 0;

    for (; *fmt; fmt++) {

        if (*fmt != '%') {
            fill_outbuf(&out, *fmt);
            continue;
        }

        /* Process flags */
        flags = 0;
repeat:
        fmt++; /* This also skips first '%' */
        switch (*fmt) {
        case '-':
            flags |= LEFT;
            goto repeat;
        case '+':
            flags |= PLUS;
            goto repeat;
        case ' ':
            flags |= SPACE;
            goto repeat;
        case '#':
            flags |= HEX_PREP;
            goto repeat;
        case '0':
            flags |= ZEROPAD;
            goto repeat;
        }

        /* Get field width */
        field_width = -1;
        if (is_digit(*fmt)) {
            field_width = ee_skip_atoi(&fmt);
        } else if (*fmt == '*') {
            fmt++;
            field_width = va_arg(args, int);
            if (field_width < 0) {
                field_width = -field_width;
                flags |= LEFT;
            }
        }

        /* Get the precision */
        precision = -1;
        if (*fmt == '.') {
            ++fmt;
            if (is_digit(*fmt)) {
                precision = ee_skip_atoi(&fmt);
            } else if (*fmt == '*') {
                ++fmt;
                precision = va_arg(args, int);
            }
            if (precision < 0)
                precision = 0;
        }

        /* Get the conversion qualifier */
        qualifier = -1;
        if (*fmt == 'l' || *fmt == 'L') {
            qualifier = *fmt;
            fmt++;
        }

        /* Default base */
        base = 10;

        switch (*fmt) {
        case 'c':
            if (!(flags & LEFT))
                while (--field_width > 0)
                    fill_outbuf(&out, ' ');

            fill_outbuf(&out, (unsigned char) va_arg(args, int));
            while (--field_width > 0)
                fill_outbuf(&out, ' ');
            continue;

        case 's':
            s = va_arg(args, char *);
            if (!s)
                s = "<NULL>";
            len = strnlen(s, precision);
            if (!(flags & LEFT))
                while (len < field_width--)
                    fill_outbuf(&out, ' ');

            for (i = 0; i < len; ++i)
                fill_outbuf(&out, *s++);

            while (len < field_width--)
                fill_outbuf(&out, ' ');
            continue;

        case 'p':
            if (field_width == -1) {
                field_width = 2 * sizeof(void *);
                flags |= ZEROPAD;
            }
            out_number(&out, (unsigned long) va_arg(args, void *),
                       16, field_width, precision, flags);
            continue;

        case 'A':
            flags |= UPPERCASE;

        case 'a':
            if (qualifier == 'l')
                out_eaddr(&out, va_arg(args, unsigned char *),
                          field_width, precision, flags);
            else
                out_iaddr(&out, va_arg(args, unsigned char *),
                          field_width, precision, flags);
            continue;

            /* Integer number formats - set up the flags and "break" */
        case 'o':
            base = 8;
            break;

        case 'X':
            flags |= UPPERCASE;

        case 'x':
            base = 16;
            break;

        case 'd':
        case 'i':
            flags |= SIGN;

        case 'u':
            break;

#ifdef HAS_FLOAT

        case 'f':
            out_flt(&out, va_arg(args, double),
                    field_width, precision, *fmt, flags | SIGN);
            continue;

#endif

        default:
            if (*fmt != '%')
                fill_outbuf(&out, '%');
            if (*fmt)
                fill_outbuf(&out, *fmt);
            else
                --fmt;
            continue;
        }

        if (qualifier == 'l')
            num = va_arg(args, unsigned long);
        else if (flags & SIGN)
            num = va_arg(args, int);
        else
            num = va_arg(args, unsigned int);

        out_number(&out, num, base, field_width, precision, flags);
    }

    fill_outbuf(&out, '\0');
    return out.num_printed - 1; /* don't include terminating null byte */
}

#define PRINTF_BUF_LEN (4*80)
static int ee_vprintf(const char *fmt, va_list args)
{
    /* XXX Replace ee_printf() with a version that does not need buffers */
    char buf[PRINTF_BUF_LEN];
    int n;

    n = vsnprintf(buf, PRINTF_BUF_LEN, fmt, args);
    assert(n < PRINTF_BUF_LEN);

    return solo5_console_write(buf, n);
}

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

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

    return ret;
}

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

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

    return ret;
}