LibrePilot/flight/libraries/printf-stdarg.c

/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 *
 * @file       printf-stdarg.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
 *             Parts by Thorsten Klose (tk@midibox.org)
 * @brief      Formatted print functions
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * 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, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/*
        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);
    }
#ifdef PIOS_COM_DEBUG
    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);
}

/**
 * @}
 */