InfoMagic Source Code 1993 July/THE_SOURCE_CODE_CD_ROM.iso/bsd_srcs/lib/libc/gen/vis.c

C/C++ Source or Header | 1992-02-06 | 4.5 KB | 185 lines

/*-
 * Copyright (c) 1989 The Regents of the University of California.
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the University of
 *    California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)vis.c    5.6 (Berkeley) 2/5/92";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <limits.h>
#include <ctype.h>
#include <vis.h>

#define    isoctal(c)    (((u_char)(c)) >= '0' && ((u_char)(c)) <= '7')

/*
 * vis - visually encode characters
 */
char *
vis(dst, c, flag, nextc)
    register char *dst;
    int c, nextc;
    register int flag;
{
    if ((u_int)c <= UCHAR_MAX && isgraph(c) ||
       ((flag & VIS_SP) == 0 && c == ' ') ||
       ((flag & VIS_TAB) == 0 && c == '\t') ||
       ((flag & VIS_NL) == 0 && c == '\n') ||
       ((flag & VIS_SAFE) && (c == '\b' || c == '\007' || c == '\r'))) {
        *dst++ = c;
        if (c == '\\' && (flag & VIS_NOSLASH) == 0)
            *dst++ = '\\';
        *dst = '\0';
        return (dst);
    }

    if (flag & VIS_CSTYLE) {
        switch(c) {
        case '\n':
            *dst++ = '\\';
            *dst++ = 'n';
            goto done;
        case '\r':
            *dst++ = '\\';
            *dst++ = 'r';
            goto done;
        case '\b':
            *dst++ = '\\';
            *dst++ = 'b';
            goto done;
#if __STDC__
        case '\a':
#else
        case '\007':
#endif
            *dst++ = '\\';
            *dst++ = 'a';
            goto done;
        case '\v':
            *dst++ = '\\';
            *dst++ = 'v';
            goto done;
        case '\t':
            *dst++ = '\\';
            *dst++ = 't';
            goto done;
        case '\f':
            *dst++ = '\\';
            *dst++ = 'f';
            goto done;
        case ' ':
            *dst++ = '\\';
            *dst++ = 's';
            goto done;
        case '\0':
            *dst++ = '\\';
            *dst++ = '0';
            if (isoctal(nextc)) {
                *dst++ = '0';
                *dst++ = '0';
            }
            goto done;
        }
    }
    if (((c & 0177) == ' ') || (flag & VIS_OCTAL)) {
        *dst++ = '\\';
        *dst++ = ((u_char)c >> 6 & 07) + '0';
        *dst++ = ((u_char)c >> 3 & 07) + '0';
        *dst++ = ((u_char)c & 07) + '0';
        goto done;
    }
    if ((flag & VIS_NOSLASH) == 0)
        *dst++ = '\\';
    if (c & 0200) {
        c &= 0177;
        *dst++ = 'M';
    }
    if (iscntrl(c)) {
        *dst++ = '^';
        if (c == 0177)
            *dst++ = '?';
        else
            *dst++ = c + '@';
    } else {
        *dst++ = '-';
        *dst++ = c;
    }
done:
    *dst = '\0';
    return (dst);
}

/*
 * strvis, strvisx - visually encode characters from src into dst
 *
 *    Dst must be 4 times the size of src to account for possible
 *    expansion.  The length of dst, not including the trailing NULL,
 *    is returned.
 *
 *    Strvisx encodes exactly len bytes from src into dst.
 *    This is useful for encoding a block of data.
 */
int
strvis(dst, src, flag)
    register char *dst;
    register const char *src;
    int flag;
{
    register char c;
    char *start;

    for (start = dst; c = *src;)
        dst = vis(dst, c, flag, *++src);
    *dst = '\0';
    return (dst - start);
}

int
strvisx(dst, src, len, flag)
    register char *dst;
    register const char *src;
    register size_t len;
    int flag;
{
    char *start = dst;

    while (len > 1) {
        dst = vis(dst, *src, flag, *(src+1));
        len--;
    }
    if (len)
        dst = vis(dst, *src, flag, '\0');

    return (dst - start);
}