store.h

   1 global store_bottom = 0;
   2 global store_eop = 0;
   3 global store_top = 0;
   4
   5 constant VN_NEXT = 0;
   6 constant VN_TYPE = 1;
   7 constant VN_VALUE = 2;
   8 constant VN__SIZE = (3*2);
   9
  10 global store_firstvar = 0;
  11
  12 ! Initialise the program store.
  13
  14 [ store_init bottom top;
  15         store_bottom = bottom;
  16         store_top = top;
  17         store_bottom->0 = 0;
  18         store_eop = store_bottom;
  19         string_init();
  20 ];
  21
  22 ! --- Heap management -------------------------------------------------------
  23
  24 ! Heap reinitialisation; all heap pointers are invalidated.
  25
  26 [ store_heapclean;
  27         store_firstvar = 0;
  28 ];
  29
  30 ! Create a new variable.
  31
  32 [ store_newvar varname type value  node;
  33         node = mem_alloc(VN__SIZE + strlen(varname) + 1);
  34         node-->VN_NEXT = store_firstvar;
  35         node-->VN_TYPE = type;
  36         node-->VN_VALUE = value;
  37         strcpy(node+VN__SIZE, varname);
  38         store_firstvar = node;
  39 ];
  40
  41 ! Look for an old variable.
  42
  43 [ store_searchvar varname  node;
  44         node = store_firstvar;
  45         while (node)
  46         {
  47                 if (strcmp(varname, node+VN__SIZE) == 0)
  48                         return node;
  49                 node = node-->VN_NEXT;
  50         }
  51         return 0;
  52 ];
  53
  54 ! Assign a value to a variable.
  55
  56 [ store_assign varname type value  node;
  57         node = store_searchvar(varname);
  58         if (node)
  59         {
  60                 node-->VN_TYPE = type;
  61                 node-->VN_VALUE = value;
  62                 return;
  63         }
  64         store_newvar(varname, type, value);
  65 ];
  66
  67 ! Get the contents of a variable.
  68
  69 [ store_lookup varname  node val;
  70         node = store_searchvar(varname);
  71         if (node)
  72         {
  73                 val = mem_alloc(4);
  74                 val-->0 = node-->VN_TYPE;
  75                 val-->1 = node-->VN_VALUE;
  76                 return val;
  77         }
  78         return 0;
  79 ];
  80
  81 ! List all variables.
  82
  83 [ store_listvars  var count;
  84         var = store_firstvar;
  85         count = 0;
  86         print "Variables:^";
  87         while (var)
  88         {
  89                 print "  ", (astring) var+VN__SIZE;
  90                 switch (var-->VN_TYPE)
  91                 {
  92                         TYPE_INT:
  93                                 print " integer ", var-->VN_VALUE;
  94                                 break;
  95
  96                         TYPE_STRING:
  97                                 print " string ~";
  98                                 string_print(var-->VN_VALUE);
  99                                 print "~";
 100                                 break;
 101
 102                         default:
 103                                 print " unknown type";
 104                 }
 105                 print "^";
 106
 107                 var = var-->VN_NEXT;
 108                 count++;
 109         }
 110         print "Total: ", count, "^";
 111 ];
 112
 113 ! --- Program storage -------------------------------------------------------
 114
 115 ! List the current program.
 116
 117 [ store_listprogram  line linelen;
 118         line = store_bottom;
 119         while (linelen = line->0)
 120         {
 121                 print " ", (line+1)-->0;
 122                 detokenise_stream(line+3);
 123                 line = line + linelen;
 124         }
 125 ];
 126
 127 [ store_listprogramhex  line linelen;
 128         line = store_bottom;
 129         while (linelen = line->0)
 130         {
 131                 print " ", (line+1)-->0;
 132                 detokenise_stream(line+3);
 133                 print "-> ";
 134                 hexdump(line, linelen);
 135                 line = line + linelen;
 136         }
 137 ];
 138
 139 ! Add a line to the program.
 140
 141 [ store_addline linenum cmd linelen  line i;
 142         line = store_bottom;
 143         while (line->0)
 144         {
 145                 if ((line+1)-->0 >= linenum)
 146                         break;
 147                 line = line + line->0;
 148         }
 149
 150         ! Do we need to append this line to the end of the program?
 151
 152         if (line->0 == 0)
 153         {
 154                 ! Yes.
 155
 156                 line = store_eop;
 157                 store_eop->(linelen+3) = 0;
 158                 store_eop = store_eop + linelen + 3;
 159         }
 160         else
 161         {
 162                 ! Do we need to remove an existing line first?
 163
 164                 if ((line+1)-->0 == linenum)
 165                 {
 166                         i = line->0;
 167                         memcpy(line, line+i, store_eop-line-i);
 168                         store_eop = store_eop - i;
 169                         store_eop->0 = 0;
 170                 }
 171
 172                 ! If there's no actual data in the new line, give up.
 173
 174                 if (linelen == 1)
 175                         return 0;
 176
 177                 ! Open up space for the new line.
 178
 179                 memcpy(line+linelen+3, line, store_eop-line);
 180                 store_eop = store_eop + linelen + 3;
 181                 store_eop->0 = 0;
 182         }
 183
 184         ! Copy the line in.
 185
 186         line->0 = linelen+3;
 187         (line+1)-->0 = linenum;
 188         memcpy(line+3, cmd, linelen);
 189
 190         return 0;
 191 ];
 192
 193 ! Find a line, by number.
 194
 195 [ store_findline lineno  line;
 196         line = store_bottom;
 197         while (line->0 && ((line+1)-->0 ~= lineno))
 198                 line = line + line->0;
 199         if (line->0 == 0)
 200                 return 0;
 201         return line;
 202 ];
 203