gno/bin/less/option.c

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/*
* Process command line options.
*
* Each option is a single letter which controls a program variable.
* The options have defaults which may be changed via
* the command line option, toggled via the "-" command,
* or queried via the "_" command.
*/
#pragma noroot
#include "less.h"
#include "option.h"
#ifdef _ORCAC_
segment "LoadSegONE";
#endif
static struct option *pendopt;
public int plusoption;
static char *propt(int c);
static char *optstring(char *s, int c);
static int flip_triple(int val, int lc);
static void nostring(int c);
extern int screen_trashed;
extern char *every_first_cmd;
/*
* Scan an argument (either from the command line or from the
* LESS environment variable) and process it.
*/
public void
scan_option(s)
char *s;
{
register struct option *o;
register int c;
char *str;
int set_default;
PARG parg;
if (s == NULL)
return;
/*
* If we have a pending string-valued option, handle it now.
* This happens if the previous option was, for example, "-P"
* without a following string. In that case, the current
* option is simply the string for the previous option.
*/
if (pendopt != NULL)
{
(*pendopt->ofunc)(INIT, s);
pendopt = NULL;
return;
}
set_default = 0;
while (*s != '\0')
{
/*
* Check some special cases first.
*/
switch (c = *s++)
{
case ' ':
case '\t':
case END_OPTION_STRING:
continue;
case '-':
/*
* "-+" means set these options back to their defaults.
* (They may have been set otherwise by previous
* options.)
*/
if (set_default = (*s == '+'))
s++;
continue;
case '+':
/*
* An option prefixed by a "+" is ungotten, so
* that it is interpreted as less commands
* processed at the start of the first input file.
* "++" means process the commands at the start of
* EVERY input file.
*/
plusoption = 1;
if (*s == '+')
every_first_cmd = save(++s);
else
ungetsc(s);
s = optstring(s, c);
continue;
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
/*
* Special "more" compatibility form "-<number>"
* instead of -z<number> to set the scrolling
* window size.
*/
s--;
c = 'z';
break;
}
/*
* Not a special case.
* Look up the option letter in the option table.
*/
o = findopt(c);
if (o == NULL)
{
parg.p_string = propt(c);
error("There is no %s flag (\"less -\\?\" for help)",
&parg);
quit(1);
}
switch (o->otype & OTYPE)
{
case BOOL:
if (set_default)
*(o->ovar) = o->odefault;
else
*(o->ovar) = ! o->odefault;
break;
case TRIPLE:
if (set_default)
*(o->ovar) = o->odefault;
else
*(o->ovar) = flip_triple(o->odefault,
(o->oletter == c));
break;
case STRING:
if (*s == '\0')
{
/*
* Set pendopt and return.
* We will get the string next time
* scan_option is called.
*/
pendopt = o;
return;
}
/*
* Don't do anything here.
* All processing of STRING options is done by
* the handling function.
*/
str = s;
s = optstring(s, c);
break;
case NUMBER:
*(o->ovar) = getnum(&s, c, (int*)NULL);
break;
}
/*
* If the option has a handling function, call it.
*/
if (o->ofunc != NULL)
(*o->ofunc)(INIT, str);
}
}
/*
* Toggle command line flags from within the program.
* Used by the "-" and "_" commands.
* how_toggle may be:
* OPT_NO_TOGGLE just report the current setting, without changing it.
* OPT_TOGGLE invert the current setting
* OPT_UNSET set to the default value
* OPT_SET set to the inverse of the default value
*/
public void
toggle_option(c, s, how_toggle)
int c;
char *s;
int how_toggle;
{
register struct option *o;
register int num;
int err;
PARG parg;
/*
* Look up the option letter in the option table.
*/
o = findopt(c);
if (o == NULL)
{
parg.p_string = propt(c);
error("There is no %s flag", &parg);
return;
}
if (how_toggle == OPT_TOGGLE && (o->otype & NO_TOGGLE))
{
parg.p_string = propt(c);
error("Cannot change the %s flag", &parg);
return;
}
/*
* Check for something which appears to be a do_toggle
* (because the "-" command was used), but really is not.
* This could be a string option with no string, or
* a number option with no number.
*/
switch (o->otype & OTYPE)
{
case STRING:
case NUMBER:
if (how_toggle == OPT_TOGGLE && *s == '\0')
how_toggle = OPT_NO_TOGGLE;
break;
}
/*
* Now actually toggle (change) the variable.
*/
if (how_toggle != OPT_NO_TOGGLE)
{
switch (o->otype & OTYPE)
{
case BOOL:
/*
* Boolean.
*/
switch (how_toggle)
{
case OPT_TOGGLE:
*(o->ovar) = ! *(o->ovar);
break;
case OPT_UNSET:
*(o->ovar) = o->odefault;
break;
case OPT_SET:
*(o->ovar) = ! o->odefault;
break;
}
break;
case TRIPLE:
/*
* Triple:
* If user gave the lower case letter, then switch
* to 1 unless already 1, in which case make it 0.
* If user gave the upper case letter, then switch
* to 2 unless already 2, in which case make it 0.
*/
switch (how_toggle)
{
case OPT_TOGGLE:
*(o->ovar) = flip_triple(*(o->ovar),
o->oletter == c);
break;
case OPT_UNSET:
*(o->ovar) = o->odefault;
break;
case OPT_SET:
*(o->ovar) = flip_triple(o->odefault,
o->oletter == c);
break;
}
break;
case STRING:
/*
* String: don't do anything here.
* The handling function will do everything.
*/
switch (how_toggle)
{
case OPT_SET:
case OPT_UNSET:
error("Can't use \"-+\" or \"--\" for a string flag",
NULL_PARG);
return;
}
break;
case NUMBER:
/*
* Number: set the variable to the given number.
*/
switch (how_toggle)
{
case OPT_TOGGLE:
num = getnum(&s, '\0', &err);
if (!err)
*(o->ovar) = num;
break;
case OPT_UNSET:
*(o->ovar) = o->odefault;
break;
case OPT_SET:
error("Can't use \"--\" for a numeric flag",
NULL_PARG);
return;
}
break;
}
}
/*
* Call the handling function for any special action
* specific to this option.
*/
if (o->ofunc != NULL)
(*o->ofunc)((how_toggle==OPT_NO_TOGGLE) ? QUERY : TOGGLE, s);
/*
* Print a message describing the new setting.
*/
switch (o->otype & OTYPE)
{
case BOOL:
case TRIPLE:
/*
* Print the odesc message.
*/
error(o->odesc[*(o->ovar)], NULL_PARG);
break;
case NUMBER:
/*
* The message is in odesc[1] and has a %d for
* the value of the variable.
*/
parg.p_int = *(o->ovar);
error(o->odesc[1], &parg);
break;
case STRING:
/*
* Message was already printed by the handling function.
*/
break;
}
if (how_toggle != OPT_NO_TOGGLE && (o->otype & REPAINT))
screen_trashed = 1;
}
/*
* "Toggle" a triple-valued option.
*/
static int
flip_triple(val, lc)
int val;
int lc;
{
if (lc)
return ((val == 1) ? 0 : 1);
else
return ((val == 2) ? 0 : 2);
}
/*
* Return a string suitable for printing as the "name" of an option.
* For example, if the option letter is 'x', just return "-x".
*/
static char *
propt(c)
int c;
{
static char buf[8];
sprintf(buf, "-%s", prchar(c));
return (buf);
}
/*
* Determine if an option is a single character option (BOOL or TRIPLE),
* or if it a multi-character option (NUMBER).
*/
public int
single_char_option(c)
int c;
{
register struct option *o;
o = findopt(c);
if (o == NULL)
return (1);
return (o->otype & (BOOL|TRIPLE|NOVAR|NO_TOGGLE));
}
/*
* Return the prompt to be used for a given option letter.
* Only string and number valued options have prompts.
*/
public char *
opt_prompt(c)
int c;
{
register struct option *o;
o = findopt(c);
if (o == NULL || (o->otype & (STRING|NUMBER)) == 0)
return (NULL);
return (o->odesc[0]);
}
/*
* Return whether or not there is a string option pending;
* that is, if the previous option was a string-valued option letter
* (like -P) without a following string.
* In that case, the current option is taken to be the string for
* the previous option.
*/
public int
isoptpending(void)
{
return (pendopt != NULL);
}
/*
* Print error message about missing string.
*/
static void
nostring(c)
int c;
{
PARG parg;
parg.p_string = propt(c);
error("String is required after %s", &parg);
}
/*
* Print error message if a STRING type option is not followed by a string.
*/
public void
nopendopt(void)
{
nostring(pendopt->oletter);
}
/*
* Scan to end of string or to an END_OPTION_STRING character.
* In the latter case, replace the char with a null char.
* Return a pointer to the remainder of the string, if any.
*/
static char *
optstring(s, c)
char *s;
int c;
{
register char *p;
if (*s == '\0')
{
nostring(c);
quit(1);
}
for (p = s; *p != '\0'; p++)
if (*p == END_OPTION_STRING)
{
*p = '\0';
return (p+1);
}
return (p);
}
/*
* Translate a string into a number.
* Like atoi(), but takes a pointer to a char *, and updates
* the char * to point after the translated number.
*/
public int
getnum(sp, c, errp)
char **sp;
int c;
int *errp;
{
register char *s;
register int n;
register int neg;
PARG parg;
s = skipsp(*sp);
neg = 0;
if (*s == '-')
{
neg = 1;
s++;
}
if (*s < '0' || *s > '9')
{
if (errp != NULL)
{
*errp = 1;
return (-1);
}
parg.p_string = propt(c);
error("Number is required after %s", &parg);
quit(1);
}
n = 0;
while (*s >= '0' && *s <= '9')
n = 10 * n + *s++ - '0';
*sp = s;
if (errp != NULL)
*errp = 0;
if (neg)
n = -n;
return (n);
}