sscanf.cpp

/*
 * Copyright (c) 2000-2002 Opsycon AB  (www.opsycon.se)
 * 
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by Opsycon AB.
 * 4. 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 "sscanf.h"

#define MAXLN 200
// http://web.mit.edu/10.001/Web/Course_Notes/c_Notes/tips_printf.html
/*alert (beep) \a
  backslash \\
  backspace \b
  carriage return \r
  double quote  \"
  formfeed  \f
  horizontal tab  \t
  newline \n
  null character  \0
  single quote  \'
  vertical tab  \v
  question mark \?
*/
#define ISSPACE " \t\n\r\f\v"

size_t strcspn (const char *p, const char *s){
    int i, j;

    for (i = 0; p[i]; i++) {
        for (j = 0; s[j]; j++) {
            if (s[j] == p[i])
                break;
        }
        if (s[j])
            break;
    }
    return (i);
}

char * _getbase(char *p, int *basep){
    if (p[0] == '0') {
        switch (p[1]) {
        case 'x':
            *basep = 16;
            break;
        case 't': case 'n':
            *basep = 10;
            break;
        case 'o':
            *basep = 8;
            break;
        default:
            *basep = 10;
            return (p);
        }
        return (p + 2);
    }
    *basep = 10;
    return (p);
}

/*
 *  _atob(vp,p,base)
 */
int _atob (uint32_t *vp, char *p, int base){
    uint32_t value, v1, v2;
    char *q, tmp[20];
    int digit;

    if (p[0] == '0' && (p[1] == 'x' || p[1] == 'X')) {
        base = 16;
        p += 2;
    }

    if (base == 16 && (q = strchr (p, '.')) != 0) {
        if (q - p > sizeof(tmp) - 1)
            return (0);

        strncpy (tmp, p, q - p);
        tmp[q - p] = '\0';
        if (!_atob (&v1, tmp, 16))
            return (0);

        q++;
        if (strchr (q, '.'))
            return (0);

        if (!_atob (&v2, q, 16))
            return (0);
        *vp = (v1 << 16) + v2;
        return (1);
    }

    value = *vp = 0;
    for (; *p; p++) {
        if (*p >= '0' && *p <= '9')
            digit = *p - '0';
        else if (*p >= 'a' && *p <= 'f')
            digit = *p - 'a' + 10;
        else if (*p >= 'A' && *p <= 'F')
            digit = *p - 'A' + 10;
        else
            return (0);

        if (digit >= base)
            return (0);
        value *= base;
        value += digit;
    }
    *vp = value;
    return (1);
}

/*
 *  atob(vp,p,base) 
 *      converts p to binary result in vp, rtn 1 on success
 */
int atob(uint32_t *vp, char *p, int base){
    uint32_t v;
    if (base == 0)
        p = _getbase (p, &base);
    if (_atob (&v, p, base)) {
        *vp = v;
        return (1);
    }
    return (0);
}

/*
 *  vsscanf(buf,fmt,ap)
 */

int vsscanf (const char *buf, const char *s, va_list ap){
    uint32_t             count, noassign, width, base, lflag;
    const char     *tc;
    char           *t, tmp[MAXLN];

    count = noassign = width = lflag = 0;
    while (*s && *buf) {
    while (isspace (*s))
        s++;
    if (*s == '%') {
        s++;
        for (; *s; s++) {
        if (strchr ("dibouxcsefg%", *s))
            break;
        if (*s == '*')
            noassign = 1;
        else if (*s == 'l' || *s == 'L')
            lflag = 1;
        else if (*s >= '1' && *s <= '9') {
            for (tc = s; isdigit (*s); s++);
            strncpy (tmp, tc, s - tc);
            tmp[s - tc] = '\0';
            atob (&width, tmp, 10);
            s--;
        }
        }
        if (*s == 's') {
        while (isspace (*buf))
            buf++;
        if (!width)
            width = strcspn (buf, ISSPACE);
        if (!noassign) {
            strncpy (t = va_arg (ap, char *), buf, width);
            t[width] = '\0';
        }
        buf += width;
        } else if (*s == 'c') {
        if (!width)
            width = 1;
        if (!noassign) {
            strncpy (t = va_arg (ap, char *), buf, width);
            t[width] = '\0';
        }
        buf += width;
        } else if (strchr ("dobxu", *s)) {
        while (isspace (*buf))
            buf++;
        if (*s == 'd' || *s == 'u')
            base = 10;
        else if (*s == 'x')
            base = 16;
        else if (*s == 'o')
            base = 8;
        else if (*s == 'b')
            base = 2;
        if (!width) {
            if (isspace (*(s + 1)) || *(s + 1) == 0)
            width = strcspn (buf, ISSPACE);
            else
            width = strchr (buf, *(s + 1)) - buf;
        }
        strncpy (tmp, buf, width);
        tmp[width] = '\0';
        buf += width;
        if (!noassign)
            atob (va_arg (ap, uint32_t *), tmp, base);
        }
        if (!noassign)
        count++;
        width = noassign = lflag = 0;
        s++;
    } else {
        while (isspace (*buf))
        buf++;
        if (*s != *buf)
        break;
        else
        s++, buf++;
    }
    }
    return (count);
}


int sscanf (const char *buf, const char *fmt, ...){
    int count;
    va_list ap;
    
    va_start (ap, fmt);
    count = vsscanf (buf, fmt, ap);
    va_end (ap);
    return (count);
}