stm32f4x/lib/printf.c

/*
 * `write' is the only external dependency for this file,
 * if you have a working write, leave it commented out.
 * If not, uncomment the define below and
 * replace outbyte(c) by your own function call.
 */
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <stdarg.h>

#define PAD_RIGHT 1
#define PAD_ZERO 2

static void printchar(char **str, int c)
{
    if (str) {
        **str = (char)c;
        ++(*str);
    } else {
        if (c == '\n') {
            write(STDOUT_FILENO, "\r\n", 2);
        } else {
            write(STDOUT_FILENO, &c, 1);
        }
    }
}

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 16

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 = (unsigned int)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 = (unsigned int)-i;
    }

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

    while (u) {
        t = (unsigned int)u % b;
        if( t >= 10 )
            t += letbase - '0' - 10;
        *--s = (char)(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;
            }
            if (*format == 'l') {
                ++format;
            }

            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 );
}

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

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

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

    ( void ) count;

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