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| #include <stdio.h>
#include <error.h>
#include <config.h>
static char cellspace[30000];
static char *data_pointer;
int process_command(char command, FILE *file_ptr)
{
char c;
long pos;
switch(command) {
case '>':
++data_pointer;
break;
case '<':
--data_pointer;
break;
case '+':
++*data_pointer;
break;
case '-':
--*data_pointer;
break;
case '.':
putchar(*data_pointer);
break;
case ',':
*data_pointer = getchar();
break;
case '[':
pos = ftell (file_ptr);
while(*data_pointer != NULL) {
fseek (file_ptr, pos, SEEK_SET);
c = getc(file_ptr);
while( c!= ']' && c != EOF) {
process_command(c, file_ptr);
c = getc(file_ptr);
}
}
}
}
int interpret_source(const char *source) {
/*
* Allowed brainfuck commands are,
* > increment the data pointer (to point to the next cell to the right).
* < decrement the data pointer (to point to the next cell to the left).
* + increment (increase by one) the byte at the data pointer.
* - decrement (decrease by one) the byte at the data pointer.
* . output the value of the byte at the data pointer.
* , accept one byte of input, storing its value in the byte at the data pointer.
* [ if the byte at the data pointer is zero,
* then instead of moving the instruction pointer forward to the next command,
* jump it forward to the command after the matching ] command.
* ] if the byte at the data pointer is nonzero,
* then instead of moving the instruction pointer forward to the next command,
* jump it back to the command after the matching [ command.
*/
char command;
FILE *file_ptr = fopen(source, "r");
if (!file_ptr) {
fprintf(stderr, "Error: No such file %s\n", source);
return FALSE;
}
while((command = getc(file_ptr)) != EOF)
process_command(command, file_ptr);
fclose(file_ptr);
return TRUE;
}
int main(int argc, char **argv)
{
/* Init data_pointer to the left most cell */
data_pointer = &cellspace[0];
/* Use getopts? */
if (argc > 1)
interpret_source(argv[1]);
return 0;
}
|
