lynx-dev SH_EX questions

[Leonid Pauzner]

I have the following simple questions:


1) why this private strncmp() introduced in mainloop -
if there is some sence it should be public in WWW/.../HTStrings.c:


#define NOT_EQU 1

PRIVATE int str_n_cmp(const char *p, const char *q, int n)
{
    if (n == 0)
        return 0;

    if (p == NULL)
        return NOT_EQU;

    if (q == NULL)
        return NOT_EQU;

    return strncmp(p, q, n);
}

#undef strncmp
#define strncmp(p, q, r)        str_n_cmp(p, q, r)

#endif  /* SH_EX */



2) Could someone explain me how does this case independent comparison work?
Where does it takes an information on case mapping (on punctuation characters,
on upper half, etc.)?


#ifdef SH_EX    /* 1997/12/23 (Tue) 16:40:31 */

/*
 * This array is designed for mapping upper and lower case letter
 * together for a case independent comparison.  The mappings are
 * based upon ascii character sequences.
 */
static unsigned char charmap[] = {
        '\000', '\001', '\002', '\003', '\004', '\005', '\006', '\007',
        '\010', '\011', '\012', '\013', '\014', '\015', '\016', '\017',
        '\020', '\021', '\022', '\023', '\024', '\025', '\026', '\027',
        '\030', '\031', '\032', '\033', '\034', '\035', '\036', '\037',
        '\040', '\041', '\042', '\043', '\044', '\045', '\046', '\047',
        '\050', '\051', '\052', '\053', '\054', '\055', '\056', '\057',
        '\060', '\061', '\062', '\063', '\064', '\065', '\066', '\067',
        '\070', '\071', '\072', '\073', '\074', '\075', '\076', '\077',
        '\100', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
        '\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
        '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
        '\170', '\171', '\172', '\133', '\134', '\135', '\136', '\137',
        '\140', '\141', '\142', '\143', '\144', '\145', '\146', '\147',
        '\150', '\151', '\152', '\153', '\154', '\155', '\156', '\157',
        '\160', '\161', '\162', '\163', '\164', '\165', '\166', '\167',
        '\170', '\171', '\172', '\173', '\174', '\175', '\176', '\177',
        '\200', '\201', '\202', '\203', '\204', '\205', '\206', '\207',
        '\210', '\211', '\212', '\213', '\214', '\215', '\216', '\217',
        '\220', '\221', '\222', '\223', '\224', '\225', '\226', '\227',
        '\230', '\231', '\232', '\233', '\234', '\235', '\236', '\237',
        '\240', '\241', '\242', '\243', '\244', '\245', '\246', '\247',
        '\250', '\251', '\252', '\253', '\254', '\255', '\256', '\257',
        '\260', '\261', '\262', '\263', '\264', '\265', '\266', '\267',
        '\270', '\271', '\272', '\273', '\274', '\275', '\276', '\277',
        '\340', '\341', '\342', '\343', '\344', '\345', '\346', '\347',
        '\350', '\351', '\352', '\353', '\354', '\355', '\356', '\357',
        '\360', '\361', '\362', '\363', '\364', '\365', '\366', '\327',
        '\370', '\371', '\372', '\373', '\374', '\375', '\376', '\337',
        '\340', '\341', '\342', '\343', '\344', '\345', '\346', '\347',
        '\350', '\351', '\352', '\353', '\354', '\355', '\356', '\357',
        '\360', '\361', '\362', '\363', '\364', '\365', '\366', '\367',
        '\370', '\371', '\372', '\373', '\374', '\375', '\376', '\377',
};

PUBLIC int strcasecomp ARGS2(
        CONST char*,    s1,
        CONST char*,    s2)
{
    register unsigned char *cm = charmap;
    register unsigned char *us1 = (unsigned char *)s1;
    register unsigned char *us2 = (unsigned char *)s2;

    while (cm[*us1] == cm[*us2++])
        if (*us1++ == '\0')
            return(0);
    return (cm[*us1] - cm[*--us2]);
}

PUBLIC int strncasecomp ARGS3(
        CONST char*,    a,
        CONST char*,    b,
        int,            n)
{
    register unsigned char *cm = charmap;
    register unsigned char *us1 = (unsigned char *)a;
    register unsigned char *us2 = (unsigned char *)b;

    while ((long)(--n) >= 0 && cm[*us1] == cm[*us2++])
        if (*us1++ == '\0')
            return(0);
    return ((long)n < 0 ? 0 : cm[*us1] - cm[*--us2]);
}

#else
...



3) Seems this piece of code wants to be rewritten:

PUBLIC char *LYSysShell NOARGS
{
    char *shell = 0;
#ifdef DOSPATH
#ifdef WIN_EX
    shell = getenv("SHELL");
    if (shell) {
        if (access(shell, 0) != 0)
            shell = getenv("COMSPEC");
    }
    if (shell == NULL) {
        if (system_is_NT)
            shell = "cmd.exe";
        else
            shell = "command.com";
    }
#else
    shell = getenv("SHELL");
    if (shell == NULL) {
        shell = getenv("COMSPEC");
    }
    if (shell == NULL) {
        shell = "command.com";
    }
#endif  /* WIN_EX */
#else
#ifdef __EMX__
    if (getenv("SHELL") != NULL) {
        shell = getenv("SHELL");
    } else {
        shell = (getenv("COMSPEC") == NULL) ? "cmd.exe" : getenv("COMSPEC");
    }
#else
#ifdef VMS
    shell = "";
#else
    shell = "exec $SHELL";
#endif /* __EMX__ */
#endif /* VMS */
#endif /* DOSPATH */
    return shell;
}