Stable.h: Bit masks, Stable.c: complete functions
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1efdeaf3e7
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158a461ebf
182
stable.c
182
stable.c
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@ -47,6 +47,62 @@ STD st_create(int st_size){
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* Algorithm:
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*/
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int st_install(STD sym_table, char *lexeme, char type, int line){
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unsigned int offset, i;
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char f_realloc = UNSET_R_FLAG; /* Reallocation flag. Initially 0 */
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/* Cannot add new entry, table full */
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if (sym_table.st_offset >= sym_table.st_size)
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return -1;
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/* Look for an existing entry in the symbol table */
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if ((offset = st_lookup(sym_table, lexeme)) > -1)
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return offset;
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/* Set proper pointer values on symbol table */
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sym_table.pstvr[sym_table.st_offset].plex = b_setmark(sym_table.plsBD, b_size(sym_table.plsBD));
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sym_table.pstvr[sym_table.st_offset].o_line = line;
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/* Add lexeme to the symbol table's lexeme buffer */
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for (i = 0; i < strlen(lexeme); ++i){
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if (!b_addc(sym_table.plsBD, lexeme[i]))
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return -1;
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if (b_rflag(sym_table.plsBD)== SET_R_FLAG)
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f_realloc = SET_R_FLAG;
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}
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if (!b_addc(sym_tabl.plsBD, '\0'))
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return -1;
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/* Set the default mask before setting the rest of the masks */
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sym_table.pstvr[sym_table.st_offset].status_field = DEFAULT_MASK;
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switch (type){
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case 'I': /* Integer type */
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sym_table.pstvr[sym_table.st_offset].status_field != INT_MASK;
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sym_Table.pstvr[sym_table.st_offset].i_value.int_val = 0;
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break;
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case 'F': /* Floating point type */
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sym_table.pstvr[sym_table.st_offset].status_field != FLT_MASK;
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sym_Table.pstvr[sym_table.st_offset].i_value.int_val = 0.0f;
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break;
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case 'S': /* String type */
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sym_table.pstvr[sym_table.st_offset].status_field != STR_MASK;
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sym_Table.pstvr[sym_table.st_offset].i_value.str_offset = -1;
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break;
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default:
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return -1; /* Not supposed to fall into here */
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}
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/* TODO: Handle reallocation flag behaviour
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if (f_realloc == SET_R_FLAG){
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}
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*/
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/* Increment the symbol table offset */
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st_incoffset();
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return sym_table.st_offset;
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}
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@ -55,7 +111,17 @@ int st_install(STD sym_table, char *lexeme, char type, int line){
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* Version: 0.1
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*/
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int st_lookup(STD sym_table, char *lexeme){
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int idx, i; /* idx: index locatio for symbol table, i: increment counter*/
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char *head;
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head = b_setmark(sym_table.plsBD, 0); /*Get head of the lexeme storage */
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for (i = 0; i < sym_table.st_offset; ++i) {
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if (strcmp(lexeme, head + idx) == 0)
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return i;
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else
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idx+= (short)(strlen(head + idx) + 1);
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}
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return -1; /* Found nothing */
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}
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/* Change the data type indicator of the variable entry located
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@ -65,6 +131,32 @@ int st_lookup(STD sym_table, char *lexeme){
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*/
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int st_change_type(STD sym_table, int vid_offset, char v_type) {
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/* Do nothing if update flag has already been set */
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if ((sym_table.pstvr[vid_offset].status_field & U_MASK)) return -1;
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/* Reset to new type with default mask and update flag
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Note: Can separate the statements to set the update flag at the
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end, but this resets AND updates at once
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*/
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sym_table.psvtr[vid_offset].status_field = sym_table.psvtr[vid_offset].status_field & DFT_U_MASK;
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/*TODO: Ask if re-setting flags and "bailing out" is spec breaking, and
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if flags should only be set if v_type is valid */
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switch (v_type){
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case 'I': /* Integer type */
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sym_table.pstvr[sym_table.st_offset].status_field != INT_MASK;
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break;
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case 'F': /* Floating point type */
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sym_table.pstvr[sym_table.st_offset].status_field != FLT_MASK;
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break;
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case 'S': /* String type, do nothing as it cannot be changed */
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break;
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default:
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return -1; /* Not supposed to fall into here */
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}
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return 1;
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}
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/* Change the i_value of the variable located by vid_offset to new Value
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@ -76,7 +168,8 @@ int st_change_type(STD sym_table, int vid_offset, char v_type) {
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* Algorithm:
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*/
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int st_change_value(STD sym_table, int vid_offset, Value value){
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sym_table.pstvr[vid_offset].i_value = value;
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return vid_offset;
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}
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/* Get the type of the variable specified by vid_offset
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@ -88,7 +181,18 @@ int st_change_value(STD sym_table, int vid_offset, Value value){
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* Algorithm:
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*/
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char st_get_type(STD sym_table, int vid_offset){
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unsigned short mask;
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mask = sym_table.pstvr[vid_offset].status_field & CHK_MASK;
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switch (mask){
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case INT_MASK:
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return 'I';
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case FLT_MASK:
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return 'F';
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case STR_MASK:
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return 'S';
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default:
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return -1; /* Not supposed to fall into here */
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}
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}
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/* Return the i_value of the variable specified by vid_offset
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@ -100,7 +204,7 @@ char st_get_type(STD sym_table, int vid_offset){
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* Algorithm:
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*/
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Value st_get_value(STD sym_table, int vid_offset){
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return sym_table.pstvr[vid_offset].i_value;
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}
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/* Free memory used by the symbol table
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@ -112,7 +216,11 @@ Value st_get_value(STD sym_table, int vid_offset){
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* Algorithm:
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*/
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void st_destroy(STD sym_table){
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if (sym_table.pstvr != NULL){
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free(sym_table.pstvr);
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sym_table.pstvr = NULL;
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}
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b_free(sym_table.plsBD);
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}
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/* Print the contents of the symbol table to standard output
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@ -124,8 +232,58 @@ void st_destroy(STD sym_table){
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* Algorithm:
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*/
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int st_print(STD sym_table){
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int i;
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if (sym_table.st_size <=0) return -1;
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printf("Symbol Table\n____________\nLine Number\tVariable Identifier");
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for(i = 0; i < sym_table.st_offset; ++i)
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printf("%2d\t%s\n", sym_table.pstvr[i].o_line, sym_table.pstvr[i].plex);
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return i;
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}
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/* Store the symbol table to a file named $stable.ste.
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It overwrites any existing file named $stable.ste.
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* Author: Victor Fernandes, 040772243
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* Version: 0.0.1
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* Called functions:
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* Parameters:
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* Return value:
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* Algorithm:
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*/
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int st_store(STD sym_table){
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FILE *out; /* The target file*/
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int i;
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if((out = fopen("$stable.ste", "w+")) == NULL)
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return -1; /* Can't open file, stop. */
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fprintf(out, "%d", sym_table.st_size);
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for(i = 0; i < sym_table.st_size; ++i){
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fprintf(out, " %4X", sym_table.pstvr[i].status_field); /* Status flag */
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fprintf(out, " %d", (int)strlen(sym_table.pstvr[i].plex)); /* Length of lexeme */
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fprintf(out, " %s", sym_table.stvr[i].plex); /* The lexeme itself */
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fprintf(out, " %d", sym_table.stvr[i].o_line); /* Line number */
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/* Initial value */
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switch (st_get_type(sym_table, i)){
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case 'I':
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fprintf(out,"");
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break;
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case 'F':
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fprintf(out,"");
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break;
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case 'S':
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fprintf(out,"");
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break;
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}
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}
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fclose(out);
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printf("Symbol Tavble stored\n");
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return i;
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}
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/* Internal function to set the table size to 0.
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* Author: Victor Fernandes, 040772243
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@ -136,7 +294,7 @@ int st_print(STD sym_table){
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* Algorithm:
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*/
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static void st_setsize(void){
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sym_table.st_size = 0;
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}
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/* Internal function to increment st_offset by 1.
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@ -148,21 +306,9 @@ static void st_setsize(void){
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* Algorithm:
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*/
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static void st_incoffset(void){
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++sym_table.st_offset;
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}
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/* Store the symbol table to a file named $stable.ste.
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It overwrites any existing file named $stable.ste.
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* Author: Victor Fernandes, 040772243
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* Version: 0.0.1
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* Called functions:
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* Parameters:
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* Return value:
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* Algorithm:
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*/
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int st_store(STD sym_table){
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}
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/* Sorts the table by variable name in ascending/descenging order
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* Author: Victor Fernandes, 040772243
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16
stable.h
16
stable.h
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@ -14,11 +14,26 @@
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#include <string.h>
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#include <stdio.h>
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#include "buffer.h"
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/* Masks
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16-bit field MSB-> 15 14 13 12 | 11 10 9 8 | 7 6 5 4 | 3 2 1 0 <-LSB
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0 0 0 0 | 0 0 0 0 | 0 0 0 0 | 0 0 0 0
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*/
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#define DFT_MASK 0xFFF8 /* Default mask */
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#define U_MASK 0x0001 /* Update mask */
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#define INT_MASK 0x0004 /* Integer mask */
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#define FLT_MASK 0x0002 /* Floating point mask */
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#define STR_MASK 0x0006 /* String mask*/
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#define CHK_MASK 0x0006 /* Type check mask */
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#define DFT_U_MASK 0xFFF9 /* Default mask with update flag */
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typedef union InitialValue {
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int int_val; /* Integer variable initial value */
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float fpl_val /* Floating-point variable initial value */
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int str_offset /* String variable initial value (location offset) */
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} Value;
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typedef struct SymbolTableVidRecord {
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unsigned short status_field /* Variable record status field */
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char *plex; /* Pointer to lexeme (VID name) in CA (character array) */
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@ -26,6 +41,7 @@ typedef struct SymbolTableVidRecord {
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Value i_value; /* Variable initial value */
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void *reserved; /* Reserved for future use, not needed right now */
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} STVR;
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typedef struct SymbolTableDescriptor {
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STVR *pstvr; /* Pointer to array of STVR */
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int st_size; /* Size in number of STVR elements */
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