Witam wszystkich
Ostatnio popełniłem taki oto wpis na swoim blogu: https://shizz3r.blogspot.com/2018/08/brainfuck-interpreter-in-c-fifth-day.html#more Post ten jest napisany w ostatni dzień, w którym zakończyłem projekt interpretera opartego o implementację linked listy i stosu.
Oto kod:
#include <stdio.h>
#include <sysexits.h>
#include <string.h>
#include <stdlib.h>
#define EX_SUCCESS 0
#define str1_is_less_than_str2 (strcmp("bf", file_extension) < 0)
#define str2_is_less_than_str1 (strcmp("bf", file_extension) > 0)
#define MEMSIZE 30000
#define NUMBER_OF_BF_INSTRUCTIONS 8
#define FIRST_ELEMENT_NOT_EXISTS (*head_ptr == NULL)
struct bf_instruction_node
{
int bf_instruction;
struct bf_instruction_node *next_element;
};
struct stack_node
{
struct bf_instruction_node *bf_instr_ptr;
struct stack_node *link;
};
void inc_ptr(int **values_ptr)
{
++(*values_ptr);
}
void dec_ptr(int **values_ptr)
{
--(*values_ptr);
}
void check_if_value_is_correct(int *values_ptr)
{
if( *values_ptr < 0 )
{
*values_ptr = 255;
}
else if( *values_ptr > 255 )
{
*values_ptr = 0;
}
}
void inc_value(int *values_ptr)
{
++(*values_ptr);
check_if_value_is_correct(values_ptr);
}
void dec_value(int *values_ptr)
{
--(*values_ptr);
check_if_value_is_correct(values_ptr);
}
void print_value(int *values_ptr)
{
putchar(*values_ptr);
}
void input_value(int *values_ptr)
{
*values_ptr = getchar();
}
void push(struct stack_node **esp_ptr, struct bf_instruction_node *current_instr_ptr)
{
struct stack_node *new_element_on_the_stack;
new_element_on_the_stack = (struct stack_node *)malloc(sizeof(struct stack_node));
new_element_on_the_stack->bf_instr_ptr = current_instr_ptr;
new_element_on_the_stack->link = *esp_ptr;
*esp_ptr = new_element_on_the_stack;
}
void pop(struct stack_node **esp_ptr)
{
struct stack_node *tmp;
tmp = *esp_ptr;
*esp_ptr = (*esp_ptr)->link;
free(tmp);
}
void start_loop(int *values_ptr, struct stack_node **esp_ptr, struct bf_instruction_node **current_instr_ptr)
{
if( *values_ptr != 0 )
{
push(esp_ptr, *current_instr_ptr);
}
else
{
int balance = 0;
do
{
if( (*current_instr_ptr)->bf_instruction == '[' )
{
balance++;
}
else if ( (*current_instr_ptr)->bf_instruction == ']' )
{
balance--;
}
if( balance != 0 )
{
*current_instr_ptr = (*current_instr_ptr)->next_element;
}
} while( balance > 0 );
}
}
void end_loop(int *values_ptr, struct bf_instruction_node **current_instr_ptr, struct stack_node **esp_ptr)
{
if( *values_ptr != 0 )
{
check_if_value_is_correct(values_ptr);
*current_instr_ptr = (*esp_ptr)->bf_instr_ptr;
}
else
{
pop(esp_ptr);
}
}
void execute_instructions(int **values_ptr, struct bf_instruction_node *head_ptr, struct bf_instruction_node **current_instr_ptr)
{
struct stack_node *esp_ptr = NULL;
char brainfuck_instruction;
*current_instr_ptr = head_ptr;
while( *current_instr_ptr != NULL )
{
brainfuck_instruction = (*current_instr_ptr)->bf_instruction;
switch( brainfuck_instruction )
{
case '>': inc_ptr(values_ptr); break;
case '<': dec_ptr(values_ptr); break;
case '+': inc_value(*values_ptr); break;
case '-': dec_value(*values_ptr); break;
case '.': print_value(*values_ptr); break;
case ',': input_value(*values_ptr); break;
case '[': start_loop(*values_ptr, &esp_ptr, current_instr_ptr); break;
case ']': end_loop(*values_ptr, current_instr_ptr, &esp_ptr); break;
}
*current_instr_ptr = (*current_instr_ptr)->next_element;
}
}
struct bf_instruction_node *create_new_element(struct bf_instruction_node *head_ptr, struct bf_instruction_node **current_instr_ptr, int char_from_file)
{
struct bf_instruction_node *new_element;
*current_instr_ptr = head_ptr;
while( (*current_instr_ptr)->next_element != NULL )
*current_instr_ptr = (*current_instr_ptr)->next_element;
new_element = (struct bf_instruction_node *)malloc(sizeof(struct bf_instruction_node));
return new_element;
}
void add_instruction_to_the_list(struct bf_instruction_node **head_ptr, struct bf_instruction_node **current_instr_ptr, int char_from_file)
{
if( FIRST_ELEMENT_NOT_EXISTS )
{
*head_ptr = (struct bf_instruction_node *)malloc(sizeof(struct bf_instruction_node));
if( *head_ptr == NULL )
{
perror("Memory allocation failed");
exit(EXIT_FAILURE);
}
else
{
(*head_ptr)->bf_instruction = char_from_file;
(*head_ptr)->next_element = NULL;
*current_instr_ptr = *head_ptr;
}
}
else
{
struct bf_instruction_node *new_element = create_new_element(*head_ptr, current_instr_ptr, char_from_file);
if( new_element == NULL )
{
perror("Memory allocation failed.");
exit(EXIT_FAILURE);
}
else
{
new_element->bf_instruction = char_from_file;
new_element->next_element = NULL;
(*current_instr_ptr)->next_element = new_element;
*current_instr_ptr = new_element;
}
}
}
void print_instructions(struct bf_instruction_node *head_ptr, struct bf_instruction_node **current_instr_ptr)
{
*current_instr_ptr = head_ptr;
while( *current_instr_ptr != NULL )
{
printf("%c", (*current_instr_ptr)->bf_instruction);
*current_instr_ptr = (*current_instr_ptr)->next_element;
}
}
void clear_the_memory(struct bf_instruction_node *head_ptr, struct bf_instruction_node **current_instr_ptr)
{
struct bf_instruction_node *earlier_element;
*current_instr_ptr = head_ptr;
while( (*current_instr_ptr) != NULL )
{
earlier_element = *current_instr_ptr;
*current_instr_ptr = (*current_instr_ptr)->next_element;
free(earlier_element);
}
puts("Memory is cleared.");
}
const char *is_bf_instruction(int char_from_file)
{
const char bf_alphabet[NUMBER_OF_BF_INSTRUCTIONS] = {'>', '<', '+', '-', ',', '.', '[', ']'};
return memchr(bf_alphabet, char_from_file, sizeof(bf_alphabet));
}
const char *get_file_extension(const char *filename)
{
const char *dot = strchr(filename, '.');
if( dot == NULL )
return NULL;
const char *file_extension = dot + 1;
return file_extension;
}
int main(int argc, char **argv)
{
if( argc != 2 )
{
fprintf(stderr, "File not specified.\n");
puts("usage: ./bf_interpreter <filename.bf>");
return EX_USAGE;
}
const char *filename = argv[1];
const char *file_extension = get_file_extension(filename);
if( file_extension == NULL || str1_is_less_than_str2 || str2_is_less_than_str1 )
{
fprintf(stderr, "Incorrect file extension.\n");
puts("usage: ./bf_interpreter <filename.bf>");
return EX_DATAERR;
}
FILE *file_with_bf_code = fopen(filename, "r");
if( file_with_bf_code == NULL )
{
perror(filename);
return EX_NOINPUT;
}
int values[MEMSIZE] = {0};
int *values_ptr = values;
int char_from_file;
struct bf_instruction_node *head_ptr = NULL, *current_instr_ptr;
while( (char_from_file = fgetc(file_with_bf_code)) != EOF )
{
if( is_bf_instruction(char_from_file) != NULL )
add_instruction_to_the_list(&head_ptr, ¤t_instr_ptr, char_from_file);
}
execute_instructions(&values_ptr, head_ptr, ¤t_instr_ptr);
clear_the_memory(head_ptr, ¤t_instr_ptr);
return EX_SUCCESS;
}
Byłbym wdzięczny jeśli ktoś wskazałby mi jakiekolwiek błędy w kodzie. Im więcej wskazanych błędów, tym lepiej! Z góry wszystkim dziękuję