ash.c 1.00 read

/*
 * The read builtin.  The -e option causes backslashes to escape the
 * following character.
 *
 * This uses unbuffered input, which may be avoidable in some cases.
 */

static int
readcmd(int argc, char **argv)
{
    char **ap;
    int backslash;
    char c;
    int rflag;
    char *prompt;
    const char *ifs;
    char *p;
    int startword;
    int status;
    int i;

    rflag = 0;
    prompt = NULL;
    while ((i = nextopt("p:r")) != '\0') {
        if (i == 'p')
            prompt = optionarg;
        else
            rflag = 1;
    }
    if (prompt && isatty(0)) {
        out2str(prompt);
    }
    if (*(ap = argptr) == NULL)
        error("arg count");
    if ((ifs = bltinlookup("IFS")) == NULL)
        ifs = defifs;
    status = 0;
    startword = 1;
    backslash = 0;
    STARTSTACKSTR(p);
    for (;;) {
        if (read(0, &c, 1) != 1) {
            status = 1;
            break;
        }
        if (c == '\0')
            continue;
        if (backslash) {
            backslash = 0;
            if (c != '\n')
                goto put;
            continue;
        }
        if (!rflag && c == '\\') {
            backslash++;
            continue;
        }
        if (c == '\n')
            break;
        if (startword && *ifs == ' ' && strchr(ifs, c)) {
            continue;
        }
        startword = 0;
        if (ap[1] != NULL && strchr(ifs, c) != NULL) {
            STACKSTRNUL(p);
            setvar(*ap, stackblock(), 0);
            ap++;
            startword = 1;
            STARTSTACKSTR(p);
        } else {
put:
            STPUTC(c, p);
        }
    }
    STACKSTRNUL(p);
    /* Remove trailing blanks */
    while ((char *)stackblock() <= --p && strchr(ifs, *p) != NULL)
        *p = '\0';
    setvar(*ap, stackblock(), 0);
    while (*++ap != NULL)
        setvar(*ap, nullstr, 0);
    return status;
}