printf-stdarg.c

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/* 
 * This program is free software; you can redistribute it and/or modify 
 * it under the terms of the GNU General Public License as published by 
 * the Free Software Foundation; either version 3 of the License, or 
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
 * for more details.
 * 
 * You should have received a copy of the GNU General Public License along 
 * with this program; if not, see <http://www.gnu.org/licenses/>
 */

/*
        putchar is the only external dependency for this file,
        if you have a working putchar, leave it commented out.
        If not, uncomment the define below and
        replace outbyte(c) by your own function call.

#define putchar(c) outbyte(c)
*/
//#define putchar(c) COMSendChar(c)

#include <pios.h>

static void printchar(char **str, int c)
{
        if (str) {
                **str = c;
                ++(*str);
        }
#if defined(PIOS_INCLUDE_DEBUG_CONSOLE)
        else
                PIOS_COM_SendChar(PIOS_COM_DEBUG, c);
#endif

}

#define PAD_RIGHT 1
#define PAD_ZERO 2

static int prints(char **out, const char *string, int width, int pad)
{
        register int pc = 0, padchar = ' ';

        if (width > 0) {
                register int len = 0;
                register const char *ptr;
                for (ptr = string; *ptr; ++ptr)
                        ++len;
                if (len >= width)
                        width = 0;
                else
                        width -= len;
                if (pad & PAD_ZERO)
                        padchar = '0';
        }
        if (!(pad & PAD_RIGHT)) {
                for (; width > 0; --width) {
                        printchar(out, padchar);
                        ++pc;
                }
        }
        for (; *string; ++string) {
                printchar(out, *string);
                ++pc;
        }
        for (; width > 0; --width) {
                printchar(out, padchar);
                ++pc;
        }

        return pc;
}

/* the following should be enough for 32 bit int */
#define PRINT_BUF_LEN 12

static int printi(char **out, int i, int b, int sg, int width, int pad, int letbase)
{
        char print_buf[PRINT_BUF_LEN];
        register char *s;
        register int t, neg = 0, pc = 0;
        register unsigned int u = i;

        if (i == 0) {
                print_buf[0] = '0';
                print_buf[1] = '\0';
                return prints(out, print_buf, width, pad);
        }

        if (sg && b == 10 && i < 0) {
                neg = 1;
                u = -i;
        }

        s = print_buf + PRINT_BUF_LEN - 1;
        *s = '\0';

        while (u) {
                t = u % b;
                if (t >= 10)
                        t += letbase - '0' - 10;
                *--s = t + '0';
                u /= b;
        }

        if (neg) {
                if (width && (pad & PAD_ZERO)) {
                        printchar(out, '-');
                        ++pc;
                        --width;
                } else {
                        *--s = '-';
                }
        }

        return pc + prints(out, s, width, pad);
}

static int print(char **out, const char *format, va_list args)
{
        register int width, pad;
        register int pc = 0;
        char scr[2];

        for (; *format != 0; ++format) {
                if (*format == '%') {
                        ++format;
                        width = pad = 0;
                        if (*format == '\0')
                                break;
                        if (*format == '%')
                                goto out;
                        if (*format == '-') {
                                ++format;
                                pad = PAD_RIGHT;
                        }
                        while (*format == '0') {
                                ++format;
                                pad |= PAD_ZERO;
                        }
                        for (; *format >= '0' && *format <= '9'; ++format) {
                                width *= 10;
                                width += *format - '0';
                        }
                        if (*format == 's') {
                                register char *s = (char *)va_arg(args, int);
                                pc += prints(out, s ? s : "(null)", width, pad);
                                continue;
                        }
                        if (*format == 'd') {
                                pc += printi(out, va_arg(args, int), 10, 1, width, pad, 'a');
                                continue;
                        }
                        if (*format == 'x') {
                                pc += printi(out, va_arg(args, int), 16, 0, width, pad, 'a');
                                continue;
                        }
                        if (*format == 'X') {
                                pc += printi(out, va_arg(args, int), 16, 0, width, pad, 'A');
                                continue;
                        }
                        if (*format == 'u') {
                                pc += printi(out, va_arg(args, int), 10, 0, width, pad, 'a');
                                continue;
                        }
                        if (*format == 'c') {
                                /* char are converted to int then pushed on the stack */
                                scr[0] = (char)va_arg(args, int);
                                scr[1] = '\0';
                                pc += prints(out, scr, width, pad);
                                continue;
                        }
                } else {
out:
                        printchar(out, *format);
                        ++pc;
                }
        }
        if (out)
                **out = '\0';
        va_end(args);
        return pc;
}

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

        va_start(args, format);
        return print(0, format, args);
}

// TK: added for alternative parameter passing
int vprintf(const char *format, va_list args)
{
        return print(0, format, args);
}

int sprintf(char *out, const char *format, ...)
{
        va_list args;

        va_start(args, format);
        return print(&out, format, args);
}

// TK: added for alternative parameter passing
int vsprintf(char *out, const char *format, va_list args)
{
        char *_out;
        _out = out;
        return print(&_out, format, args);
}

int snprintf(char *buf, size_t count, const char *format, ...)
{
        va_list args;

        (void)count;

        va_start(args, format);
        return print(&buf, format, args);
}