cmdline.c

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/* cmdline.c -- command line parsing routines */
/* Copyright 1989 Carnegie Mellon University */
/*
 * This module is designed to allow various modules to scan (and rescan)
 * the command line for applicable arguments.  The goal is to hide as
 * much information about switches and their names as possible so that
 * switches become more consistent across applications and so that the
 * author of an application need not do a lot of work to provide numerous
 * options.  Instead, each module scans the command line for its own
 * arguments.
 *
 * Command lines are of the following form:
 *    command -s1 -s2 opt2 -s3 arg1 arg2 -s4 opt4 arg3
 * Note that there are three kinds of command line parameters:
 * (1) A Switch is a "-" followed by a name, e.g. "-s1"
 * (2) An Option is a Switch followed by a space and name, e.g. "-s2 opt2"
 * (3) An Argument is a name by itself, e.g. "arg1"
 * Note also that a switch followed by an argument looks just like an
 * option, so a list of valid option names is necessary to disambiguate.
 *
 * Long names are good for readability, but single character abbreviations
 * are nice for experienced users.  cmdline.c allows single character
 * abbreviations provided that they are unambiguous.  These are
 * recognized with no extra work by the programmer.  If an
 * isolated '?' is encountered in the command line, then all of
 * the options and switches are printed as help and for debugging.
 *
 * Given that we must tell this module about option names and switch
 * names, how should we do it?  We can't wait until modules are
 * initialized, since often modules want to read the command line
 * at initialization time.  In the original implementation, the
 * main program was supposed to provide names for the whole program,
 * but this violates modularity: when an option is added to a module,
 * the main program has to be modified too.  This is a real pain when
 * different machines support different options and you want to have
 * a single machine-independent main program.  The solution is to 
 * have the main program import strings describing the options and
 * switches used by each module.  These are passed into cmdline.c
 * before initialization of other modules is begun.
 *
 * A main program that uses cmdline.c should do the following:
 *   call cl_syntax(s) for each module's option/switch string.
 * The string s should have the following format:
 *  "opt1<o>description;opt2<o>description;...;switch1<s>description;..."
 * where opt1 and opt2 are option names (without the preceding "-"), and
 * switch1 is a switch name.  The <o> and <s> indicate whether the
 * name is an option or a switch.  The descriptions are arbitrary strings
 * (without semicolons) that are printed out for the user when "?"
 * is typed on the command line.
 *
 * After calling cl_syntax, main() should call
 *   cl_init(argv, argc)
 * cl_init will report an error (to stderr) if it finds any illegal
 * switch or option names in argv, and help will be printed if "?"
 * is found in argv.  If cl_init returns false, then the user has been
 * given an error message or help, and main should probably exit.
 *
 * Afterward, switches, options, and arguments can be accessed by
 * calling cl_switch, cl_option, and cl_arg.  If cl_switch or cl_option
 * is called with a switch name that was not mentioned in the call to 
 * cl_init, an error will result.  This indicates that the application
 * author omitted a valid switch or option name when calling cl_init.
 * This is an error because the full set of names is needed for error
 * checking and to distinguish arguments from options.
 *
 */

/*****************************************************************************
*       Change Log
*  Date | Change
*-----------+-----------------------------------------------------------------
* 13-Jun-86 | Created Change Log
*  6-Aug-86 | Modified for Lattice 3.0 -- use "void" to type some routines
* 20-Sep-89 | Redesigned the interface, adding cl_syntax call.
*  2-Apr-91 | JDW : further changes
* 27-Dec-93 | "@file" as first arg reads command line args from file
* 11-Mar-94 | PLu: Add private to cl_search() definition.
* 28-Apr-03 | DM: true->TRUE, false->FALSE
*****************************************************************************/

/* stdlib.h not on PMAX */
#ifndef mips
#include "stdlib.h"
#endif
#include "stdio.h"
#include "cext.h"
#include "userio.h"
#include "cmdline.h"
#include "ctype.h"
#include "string.h"

#define syntax_max 10           /* allow for 10 syntax strings */
private char *syntax[syntax_max];
private int n_syntax = 0;       /* number of strings so far */
private char **argv;            /* command line argument vector */
private int argc;               /* length of argv */

private boolean cl_rdy = FALSE;    /* set to TRUE when initialized */

#define cl_OPT 1
#define cl_SW 2
#define cl_INIT 3
#define cl_ARG 4

/*****************************************************************************
*    Routines local to this module
*****************************************************************************/
private char *cl_search();
private int find_string();
private void indirect_command(char *filename, char *oldarg0);
private void ready_check();

/****************************************************************
*           cl_arg
* Inputs:
*    n: the index of the arg needed
* Results:
*    pointer to the nth arg, or NULL if none exists
*    arg 0 is the command name
*****************************************************************/

char *cl_arg(n)
  int n;
{
    return (n <= 0 ? argv[0] :
                     cl_search((char *)NULL, cl_ARG, n));
}

/* cl_help -- print help from syntax strings */
/**/
void cl_help()
{
    register int i, j;
    int count = 0;	/* see if there are any switches or flags */

    for (i = 0; i < n_syntax; i++) {
        register char *ptr = syntax[i];
        register char c = *ptr++;
        while (c != EOS) {
            while (c != EOS && !(isalnum(c))) c = *ptr++;
            if (c != EOS) {
                count++;
                gprintf(TRANS, "-");
                j = 1;
                while (c != EOS && c != '<') {
                    gprintf(TRANS, "%c", c);
                    c = *ptr++;
                    j++;
                }
                if (c != EOS) {
                    c = *ptr++;
                    if (c == 'o') {
                        gprintf(TRANS, " xxx");
                        j += 4;
                    }
                }
                /* attempt to tab */
                do {
                    gprintf(TRANS, " ");
                } while (j++ < 16);
                while (c != EOS && c != '>') c = *ptr++;
                if (c != EOS) c = *ptr++;
                while (c != EOS && c != ';') {
                    gprintf(TRANS, "%c", c);
                    c = *ptr++;
                }
                gprintf(TRANS, "\n");
            }
        }
    }
    if (!count) gprintf(TRANS, "No switches or options exist.\n");
}

/*****************************************************************************
*           cl_init
* Inputs:
*    char *switches[]:    array of switch names
*    int nsw:   number of switch names
*    char *options[]:    array of option names
*    int nopt:  number of option names
*    char *av:  array of command line fields (argv)
*    int ac:        number of command line fields (argc)
* Effect:
*    Checks that all command line entries are valid.
*    Saves info for use by other routines.
* Returns:
*    TRUE if syntax checks OK, otherwise false
*****************************************************************************/

boolean cl_init(av, ac)
  char *av[];
  int ac;
{
    argv = av;      
    argc = ac;

    /* check for help request */
    if (argc == 2 && strcmp(argv[1], "?") == 0) {
        cl_help();
        return FALSE; /* avoid cl_search which would complain about "?" */
    }
    /* check for indirection */
    if (argc == 2 && *(argv[1]) == '@') {
        /* read new args from file */
        indirect_command(av[1] + 1, av[0]);
    }
    /* check command line syntax: */
    cl_rdy = TRUE;
    return (cl_rdy = (cl_search("true", cl_INIT, 0) != NULL));
}


/****************************************************************
*           cl_int_option
* Inputs:
*    char *name:    name of option
*    long default:  default value for option
* Result:
*    returns long encoding of the option, deflt if none
* Implementation:
*    call cl_option and sscanf result
*****************************************************************/

long cl_int_option(name, deflt)
  char *name;
  long deflt;
{
    char *opt = cl_option(name);
    if (opt) {
        if (sscanf(opt, "%ld", &deflt) != 1) {
            gprintf(TRANS, "Warning: option %s %s not an integer, ignored\n",
                        name, opt);
        }
    }
    return deflt;
}


/****************************************************************
*           cl_search