sys/ddb/db_variables.c

   1 /*
   2  * Mach Operating System
   3  * Copyright (c) 1991,1990 Carnegie Mellon University
   4  * All Rights Reserved.
   5  *
   6  * Permission to use, copy, modify and distribute this software and its
   7  * documentation is hereby granted, provided that both the copyright
   8  * notice and this permission notice appear in all copies of the
   9  * software, derivative works or modified versions, and any portions
  10  * thereof, and that both notices appear in supporting documentation.
  11  *
  12  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
  13  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  14  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  15  *
  16  * Carnegie Mellon requests users of this software to return to
  17  *
  18  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  19  *  School of Computer Science
  20  *  Carnegie Mellon University
  21  *  Pittsburgh PA 15213-3890
  22  *
  23  * any improvements or extensions that they make and grant Carnegie the
  24  * rights to redistribute these changes.
  25  *
  26  * $FreeBSD: src/sys/ddb/db_variables.c,v 1.18 1999/08/28 00:41:11 peter Exp $
  27  */
  28
  29 /*
  30  *      Author: David B. Golub, Carnegie Mellon University
  31  *      Date:   7/90
  32  */
  33
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36
  37 #include <ddb/ddb.h>
  38 #include <ddb/db_lex.h>
  39 #include <ddb/db_variables.h>
  40
  41 static int      db_find_variable (struct db_variable **varp);
  42 static void     db_write_variable (struct db_variable *, db_expr_t *);
  43
  44 #ifdef notused
  45 static int      db_set_variable (db_expr_t value);
  46 #endif
  47
  48 static struct db_variable db_vars[] = {
  49         { "radix",      &db_radix, NULL },
  50         { "maxoff",     &db_maxoff, NULL },
  51         { "maxwidth",   &db_max_width, NULL },
  52         { "tabstops",   &db_tab_stop_width, NULL },
  53 };
  54 static struct db_variable *db_evars = db_vars + NELEM(db_vars);
  55
  56 static int
  57 db_find_variable(struct db_variable **varp)
  58 {
  59         int     t;
  60         struct db_variable *vp;
  61
  62         t = db_read_token();
  63         if (t == tIDENT) {
  64             for (vp = db_vars; vp < db_evars; vp++) {
  65                 if (!strcmp(db_tok_string, vp->name)) {
  66                     *varp = vp;
  67                     return (1);
  68                 }
  69             }
  70             for (vp = db_regs; vp < db_eregs; vp++) {
  71                 if (!strcmp(db_tok_string, vp->name)) {
  72                     *varp = vp;
  73                     return (1);
  74                 }
  75             }
  76         }
  77         db_error("Unknown variable\n");
  78         return (0);
  79 }
  80
  81 int
  82 db_get_variable(db_expr_t *valuep)
  83 {
  84         struct db_variable *vp;
  85
  86         if (!db_find_variable(&vp))
  87             return (0);
  88
  89         db_read_variable(vp, valuep);
  90
  91         return (1);
  92 }
  93
  94 #ifdef notused
  95 static int
  96 db_set_variable(db_expr_t value)
  97 {
  98         struct db_variable *vp;
  99
 100         if (!db_find_variable(&vp))
 101             return (0);
 102
 103         db_write_variable(vp, &value);
 104
 105         return (1);
 106 }
 107 #endif
 108
 109 void
 110 db_read_variable(struct db_variable *vp, db_expr_t *valuep)
 111 {
 112         db_varfcn_t     *func = vp->fcn;
 113
 114         if (func == NULL)
 115             *valuep = *(vp->valuep);
 116         else
 117             (*func)(vp, valuep, DB_VAR_GET);
 118 }
 119
 120 static void
 121 db_write_variable(struct db_variable *vp, db_expr_t *valuep)
 122 {
 123         db_varfcn_t     *func = vp->fcn;
 124
 125         if (func == NULL)
 126             *(vp->valuep) = *valuep;
 127         else
 128             (*func)(vp, valuep, DB_VAR_SET);
 129 }
 130
 131 void
 132 db_set_cmd(db_expr_t dummy1, boolean_t dummy2, db_expr_t dummy3, char *dummy4)
 133 {
 134         db_expr_t       value;
 135         struct db_variable *vp;
 136         int     t;
 137
 138         t = db_read_token();
 139         if (t != tDOLLAR) {
 140             db_error("Unknown variable\n");
 141             return;
 142         }
 143         if (!db_find_variable(&vp)) {
 144             db_error("Unknown variable\n");
 145             return;
 146         }
 147
 148         t = db_read_token();
 149         if (t != tEQ)
 150             db_unread_token(t);
 151
 152         if (!db_expression(&value)) {
 153             db_error("No value\n");
 154             return;
 155         }
 156         if (db_read_token() != tEOL) {
 157             db_error("?\n");
 158         }
 159
 160         db_write_variable(vp, &value);
 161 }