Stable.h: Bit masks, Stable.c: complete functions

This commit is contained in:
Victor Fernandes 2017-03-24 21:04:45 -04:00
parent 1efdeaf3e7
commit 158a461ebf
2 changed files with 181 additions and 19 deletions

184
stable.c
View File

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

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@ -14,11 +14,26 @@
#include <string.h> #include <string.h>
#include <stdio.h> #include <stdio.h>
#include "buffer.h" #include "buffer.h"
/* Masks
16-bit field MSB-> 15 14 13 12 | 11 10 9 8 | 7 6 5 4 | 3 2 1 0 <-LSB
0 0 0 0 | 0 0 0 0 | 0 0 0 0 | 0 0 0 0
*/
#define DFT_MASK 0xFFF8 /* Default mask */
#define U_MASK 0x0001 /* Update mask */
#define INT_MASK 0x0004 /* Integer mask */
#define FLT_MASK 0x0002 /* Floating point mask */
#define STR_MASK 0x0006 /* String mask*/
#define CHK_MASK 0x0006 /* Type check mask */
#define DFT_U_MASK 0xFFF9 /* Default mask with update flag */
typedef union InitialValue { typedef union InitialValue {
int int_val; /* Integer variable initial value */ int int_val; /* Integer variable initial value */
float fpl_val /* Floating-point variable initial value */ float fpl_val /* Floating-point variable initial value */
int str_offset /* String variable initial value (location offset) */ int str_offset /* String variable initial value (location offset) */
} Value; } Value;
typedef struct SymbolTableVidRecord { typedef struct SymbolTableVidRecord {
unsigned short status_field /* Variable record status field */ unsigned short status_field /* Variable record status field */
char *plex; /* Pointer to lexeme (VID name) in CA (character array) */ char *plex; /* Pointer to lexeme (VID name) in CA (character array) */
@ -26,6 +41,7 @@ typedef struct SymbolTableVidRecord {
Value i_value; /* Variable initial value */ Value i_value; /* Variable initial value */
void *reserved; /* Reserved for future use, not needed right now */ void *reserved; /* Reserved for future use, not needed right now */
} STVR; } STVR;
typedef struct SymbolTableDescriptor { typedef struct SymbolTableDescriptor {
STVR *pstvr; /* Pointer to array of STVR */ STVR *pstvr; /* Pointer to array of STVR */
int st_size; /* Size in number of STVR elements */ int st_size; /* Size in number of STVR elements */