parse.h

   1 #define MAXCOMMAND 100
   2 #define MAXINBUFF 250000
   3 #define MAXSYMBOL 256
   4
   5 #define pInBuff *(InBuff+i)
   6
   7 /*
   8 * A_COMMAND: @value
   9 *       value is either a non-negative decimal numer of a symbol referring to such a number
  10 *
  11 * C_COMMAND: dest = comp; jump
  12 *       either of the dest or jump fields may be empty
  13 *       if dest is empty, the "=" is omitted
  14 *       if jump is emprty, the ";" is omitted
  15 */
  16 #define A_COMMAND 0
  17 #define C_COMMAND 1
  18 #define L_COMMAND 2
  19
  20 void dump_buffer();
  21
  22 /*
  23 * Resets command pointer to beginning of input buffer.
  24 */
  25 void reset_buffer();
  26
  27 void init_parser(char *FilenameBuff);
  28
  29 /*
  30 * Finds current line number of source file.
  31 * This is done for the convenience of the user.
  32 */
  33 int find_line_num();
  34
  35 /*
  36 * Search current command for term.
  37 * Ignores whitespace. Looks for one char only.
  38 */
  39 int search_command(const char *current_command, const char term);
  40
  41 /*
  42 * Print chars of current command to stdout.
  43 */
  44 void print_current_command();
  45
  46 /*
  47 * Confirms the existance of more commands in the input
  48 */
  49 int has_more_commands();
  50
  51 /*
  52 * Read next command from input and makes it the current command
  53 * Should be called only if has_more_commands() is true
  54 * Initialy there is no current command
  55 */
  56 void advance();
  57
  58 /*
  59 * Returns type of current command
  60 * See Commands comment for more info
  61 */
  62 int command_type();
  63
  64 /*
  65 * Returns symbol or decimal of current command
  66 * Should be called only when command_type() is A_COMMAND or L_COMMAND
  67 */
  68 int symbol();
  69
  70 /*
  71 * Reads command and finds symbol chars. Loads into hash
  72 */
  73 int symbol_load();
  74
  75 /*
  76 * Returns the dest mnemonic in the current C_COMMAND
  77 * Should be called only when command_type() is C_COMMAND
  78 */
  79 int dest(char dest[]);
  80
  81 /*
  82 * Returns comp mnemonic in the current C_COMMAND
  83 * Called only when command_type() is C_COMMAND
  84 */
  85 int comp(char comp[]);
  86
  87 /*
  88 * Returns the jump mnemonic in the current C_COMMAND
  89 * Called only when command_type() is C_COMMAND
  90 */
  91 int jump(char jump[]);