zephyr/zwgc/variables.c

   1 /* This file is part of the Project Athena Zephyr Notification System.
   2  * It is one of the source files comprising zwgc, the Zephyr WindowGram
   3  * client.
   4  *
   5  *      Created by:     Marc Horowitz <marc@athena.mit.edu>
   6  *
   7  *      $Id$
   8  *
   9  *      Copyright (c) 1989 by the Massachusetts Institute of Technology.
  10  *      For copying and distribution information, see the file
  11  *      "mit-copyright.h".
  12  */
  13
  14 #include <sysdep.h>
  15
  16 #if (!defined(lint) && !defined(SABER))
  17 static const char rcsid_variables_c[] = "$Id$";
  18 #endif
  19
  20 #include <zephyr/mit-copyright.h>
  21
  22 /****************************************************************************/
  23 /*                                                                          */
  24 /*   Module containing code to deal with description langauge variables:    */
  25 /*                                                                          */
  26 /****************************************************************************/
  27
  28 #include "new_memory.h"
  29 #include "notice.h"
  30 #include "string_dictionary_aux.h"
  31 #include "variables.h"
  32
  33 /*
  34  * fields_data[_length] - these point to the field data that the number
  35  *                        variables were last set to using
  36  *                        var_set_number_variables_to_fields.
  37  */
  38
  39 static char *fields_data;
  40 static int fields_data_length = 0;
  41
  42 /*
  43  * [non_]number_variable_dict - contains the values of all the [non-]number
  44  *                              variables that have been set since the last
  45  *                              var_clear_all_variables call or (for numbers
  46  *                              only) var_set_number_variables_to_fields call.
  47  */
  48
  49 static string_dictionary non_number_variable_dict = NULL;
  50 static string_dictionary number_variable_dict = NULL;
  51
  52 /*
  53  *  Internal Routine:
  54  *
  55  *    int is_digits(string text)
  56  *        Effects: Returns true iff text matches [0-9]*.  ("" matches...)
  57  */
  58
  59 static int
  60 is_digits(string text)
  61 {
  62     for (; *text; text++)
  63       if (!isdigit(*text))
  64         return(0);
  65
  66     return(1);
  67 }
  68
  69 /*
  70  *  Internal Routine:
  71  *
  72  *    int is_number_variable(string text)
  73  *        Effects: Returns true iff text matches [0-9]+.
  74  */
  75
  76 #define  is_number_variable(x)      (isdigit(*(x)) && is_digits((x)))
  77
  78 /*
  79  *    void var_clear_all_variables()
  80  *        Requires: This routine must be called before any other
  81  *                  var module routine is called.
  82  *        Modifies: All description language variables
  83  *        Effects: Sets all description langauge variables to "".
  84  */
  85
  86 void
  87 var_clear_all_variables(void)
  88 {
  89     if (non_number_variable_dict) {
  90         string_dictionary_SafeDestroy(non_number_variable_dict);
  91         string_dictionary_SafeDestroy(number_variable_dict);
  92     }
  93
  94     non_number_variable_dict = string_dictionary_Create(101);
  95     number_variable_dict = string_dictionary_Create(11);
  96     fields_data_length = 0;
  97 }
  98
  99 /*
 100  *    string var_get_variable(string name)
 101  *        Requires: var_clear_all_variables has been called
 102  *        Effects: Returns the value of the description langauge variable
 103  *                 named name.  The returned string is read-only and is
 104  *                 guarenteed to last only until the next var module
 105  *                 call.  DO NOT FREE THIS STRING.
 106  */
 107
 108 string
 109 var_get_variable(string name)
 110 {
 111     char *result;
 112     int field_to_get;
 113     static string last_get_field_call_result = NULL;
 114
 115     if (is_number_variable(name)) {
 116         if (result = string_dictionary_Fetch(number_variable_dict, name))
 117           return(result);
 118
 119         /*
 120          * Convert name to an integer avoiding overflow:
 121          */
 122         while (*name=='0')
 123           name++;
 124         if (strlen(name)>12)
 125           field_to_get = 0; /* no way we'll have > 1 trillian fields... */
 126         else
 127           field_to_get = atoi(name);
 128
 129         if (!field_to_get)
 130           return("");
 131         if (last_get_field_call_result)
 132           free(last_get_field_call_result);
 133         last_get_field_call_result = get_field(fields_data,
 134                                                fields_data_length,
 135                                                field_to_get);
 136         return(last_get_field_call_result);
 137     }
 138
 139     if (!(result = string_dictionary_Fetch(non_number_variable_dict, name)))
 140       result = "";
 141
 142     return(result);
 143 }
 144
 145 /*
 146  *    void var_set_variable(string name, value)
 147  *        Requires: var_clear_all_variables has been called
 148  *        Modifies: The value of description langauge variable
 149  *                  named name.
 150  *        Effects: Sets the description langauge variable named name
 151  *                 to have the value value.
 152  */
 153
 154 void
 155 var_set_variable(string name,
 156                  string value)
 157 {
 158     string_dictionary_Set(is_number_variable(name) ? number_variable_dict
 159                           : non_number_variable_dict, name, value);
 160 }
 161
 162 /*
 163  *    void var_set_variable_to_number(string name; int number)
 164  *        Requires: var_clear_all_variables has been called
 165  *        Modifies: The value of description langauge variable
 166  *                  named name.
 167  *        Effects: Sets the description langauge variable named name
 168  *                 to have as its value number's ascii representation.
 169  */
 170
 171 void
 172 var_set_variable_to_number(string name,
 173                            int number)
 174 {
 175     char buffer[20];
 176
 177     sprintf(buffer, "%d", number);
 178     var_set_variable(name, buffer);
 179 }
 180
 181 /*
 182  *    void var_set_variable_then_free_value(string name, value)
 183  *        Requires: var_clear_all_variables has been called, value is
 184  *                  on the heap.
 185  *        Modifies: The value of description langauge variable
 186  *                  named name, value
 187  *        Effects: Sets the description langauge variable named name
 188  *                 to have the value value then frees value.  This
 189  *                 routine is slightly faster than calling var_set_variable
 190  *                 then freeing value.  It is provided mainly for
 191  *                 convenience reasons.
 192  */
 193
 194 void
 195 var_set_variable_then_free_value(string name,
 196                                  string value)
 197 {
 198     string_dictionary_binding *binding;
 199     int exists;
 200
 201 #ifdef DEBUG_MEMORY
 202     if (!memory__on_heap_p(value))
 203       abort(); /* <<<>>> */
 204 #endif
 205
 206     if (is_number_variable(name)) {
 207         var_set_variable(name, value);
 208         free(value);
 209         return;
 210     }
 211
 212     binding = string_dictionary_Define(non_number_variable_dict, name,
 213                                        &exists);
 214     if (exists)
 215       free(binding->value);
 216     binding->value = value;
 217 }
 218
 219 /*
 220  *    void var_set_number_variables_to_fields(char *data, int length)
 221  *        Requires: var_clear_all_variables has been called
 222  *        Modifies: All numeric description language variables
 223  *        Effects: Treats data[0]..data[length-1] as a series of
 224  *                 null-seperated fields.  Sets $<number> (<number>
 225  *                 here means [0-9]+ to field # <number> in data.
 226  *                 Field 0 is defined to be "" as are all field #'s
 227  *                 greater than the number of fields in data.
 228  *                 Data[0]..data[length-1] must not be changed (or freed)
 229  *                 until either this call is made again with different
 230  *                 data or var_clear_all_variables is called.
 231  */
 232
 233 void
 234 var_set_number_variables_to_fields(char *data,
 235                                    int length)
 236 {
 237     fields_data = data;
 238     fields_data_length = length;
 239
 240     string_dictionary_SafeDestroy(number_variable_dict);
 241     number_variable_dict = string_dictionary_Create(11);
 242 }