int main(int argc, char** argv)
{
/*
* These counters will be used as offsets for messages when using pipes
* i.e. write(stack + stack_pos, strlen(stack + stack_pos))
*/
int stack_pos = 0;
int input_pos = 1;
char input[MAX_BUF_SIZE] = "";
char stack[MAX_BUF_SIZE] = "";
char result[MAX_BUF_SIZE] = "";
fgets(input, MAX_BUF_SIZE - 1, stdin);
fgets(stack, MAX_BUF_SIZE - 1, stdin);
fgets(result, MAX_BUF_SIZE - 1, stdin);
input[strcspn(input, "\n")] = 0;
stack[strcspn(stack, "\n")] = 0;
result[strcspn(result, "\n")] = 0;
if ((strlen(input) == 0)) // End of input, clearing stack
{
while (stack_pos < strlen(stack))
{
write_to_result(result, ' ');
write_to_result(result, stack[stack_pos++]);
}
if (debug)
fprintf(stderr, "pid: %d end of input! result: %s \n",
getpid(), result
);
printf("%s", result);
return 0;
}
if (debug)
fprintf(stderr, "pid: %d input[0]: %c stack: %s result: %s \n",
getpid(), input[0], stack, result
);
switch (input[0])
{
case '-': /* Odp.: Przez liczbę całkowitą należy rozumież liczbę całkowitą bez znaku */
case '^':
case '*':
case '/':
case '+':
while (stack_pos < strlen(stack))
{
/* treating every op as left-associative */
if (op_priority(input[0]) <= op_priority(stack[stack_pos]))
{
write_to_result(result, ' ');
write_to_result(result, stack[stack_pos++]);
}
else break;
}
write_to_result(result, ' ');
case '(':
write_to_stack(stack, input[0], &stack_pos);
break;
case ')':
while(stack_pos <= strlen(stack))
{
if (stack[stack_pos] != '(')
{
write_to_result(result, ' ');
write_to_result(result, stack[stack_pos++]);
}
else
{
stack_pos++;
break;
}
}
case ' ':
case '\n':
break;
default:
add_space_to_result(result);
/*
* We only checked first character of expression (input[0])
* Now let's check if there are other characters in expression
*/
for (int i = 0; i < strlen(input); i++)
{
/* When there's no space around parenthesis
* easier testing
*/
if (!isspace(input[i]) && (input[i] != ')'))
{
write_to_result(result, input[i]);
}
else
{
input_pos = i + ((input[i] != ')') ? (1) : (0));
break;
}
}
break;
}
/* Moving offset to first nonwhite character in input */
while ((input_pos < strlen(input)) && (isspace(input[input_pos]))) input_pos++;
spawn_worker(input + input_pos, stack + stack_pos, result);
return 0;
}
int main(int argc, char **argv)
{
FILE *file;
char instruction;
char* filename;
struct vector instruction_stream;
if(argc != 2)
{
/* wrong number of args */
fprintf(stderr, "Error: exactly 1 HQ9+ source file as arg required\n");
exit(EXIT_FAILURE);
}
/* open file */
filename = argv[1];
file = fopen(filename, "r");
if (file == NULL)
{
/* could not open file */
perror("Error opening file");
exit(EXIT_FAILURE);
}
/*** prologue ***/
vector_create(&instruction_stream, 100);
char prologue [] = {
0x55, // push %rbp
0x48, 0x89, 0xE5, // mov %rsp, %rbp
// backup %r12 (callee saved register)
0x41, 0x54, // pushq %r12
// store %rdi content (putchar) in %r12 as callee saved
0x49, 0x89, 0xFC, // movq %rdi, %r12
// push accumulator on stack
0x6a, 0x00, // pushq $0
};
vector_push(&instruction_stream, prologue, sizeof(prologue));
int stack_offset = -0x10; // offset from %rbp
int offset_accumulator = stack_offset; // accumulator address: -0x10(%rbp)
// hello world
write_to_stack(&instruction_stream, "Hello World\n", &stack_offset);
int offset_hello_world = stack_offset;
// source code
char* source_code = get_source_code(filename);
write_to_stack(&instruction_stream, source_code, &stack_offset);
free(source_code);
int offset_source = stack_offset;
// lyrics
char* lyrics = get_lyrics(99);
write_to_stack(&instruction_stream, lyrics, &stack_offset);
free(lyrics);
int offset_bottles = stack_offset;
// everything after accumulator is text bytes
int text_bytes_on_stack = -(stack_offset - offset_accumulator);
/*** parse file ***/
while((instruction = fgetc(file)) != EOF)
{
switch (instruction)
{
case 'H':
{
// access single chars of int
char *hw = (char*) &offset_hello_world;
char opcodes [] = {
0xB0, 00, // movb $0, %al
0x48, 0x8D, 0xBD, hw[0], hw[1], hw[2], hw[3], // leaq -0x<offset>(%rbp),%rdi
0x41, 0xFF, 0xD4 // callq *%r12
};
vector_push(&instruction_stream, opcodes, sizeof(opcodes));
}
break;
case 'Q':
{
// access single chars of int
char *s = (char*) &offset_source;
char opcodes [] = {
0xB0, 00, // movb $0, %al
0x48, 0x8D, 0xBD, s[0], s[1], s[2], s[3], // leaq -0x<offset>(%rbp),%rdi
0x41, 0xFF, 0xD4 // callq *%r12
};
vector_push(&instruction_stream, opcodes, sizeof(opcodes));
}
break;
case '9':
{
// access single chars of int
char *b = (char*) &offset_bottles;
char opcodes [] = {
0xB0, 00, // movb $0, %al
0x48, 0x8D, 0xBD, b[0], b[1], b[2], b[3], // leaq -0x<offset>(%rbp),%rdi
// 0xBF, 0x39, 0x00, 0x00, 0x00, // mov $0x39, %edi
0x41, 0xFF, 0xD4 // callq *%r12
};
vector_push(&instruction_stream, opcodes, sizeof(opcodes));
}
break;
case '+':
{
char *acc = (char*) &offset_accumulator;
char opcodes [] = {
// increment the accumulator
// TODO from variable instead of constant offset
0x48, 0xFF, 0x45, 0xF0, // incq -0x10(%rbp)
};
vector_push(&instruction_stream, opcodes, sizeof(opcodes));
}
break;
}
}
if (!feof(file)) {
perror("Error reading file");
}
fclose(file);
/*** epilogue ***/
// access single chars of long
char *t = (char*) &text_bytes_on_stack;
char epilogue [] = {
// free strings
0x48, 0x81, 0xC4, t[0], t[1], t[2], t[3], // addq $<x>, %rsp
// free accumulator
0x48, 0x83, 0xC4, 0x08, // addq $8, %rsp
// restore callee saved register
0x41, 0x5C, // popq %r12
0x5d, // pop rbp
0xC3 // ret
};
vector_push(&instruction_stream, epilogue, sizeof(epilogue));
/*** invoke generated code ***/
/* allocate and copy instruction stream into executable memory */
void* mem = mmap(NULL, instruction_stream.size, PROT_WRITE | PROT_EXEC, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
memcpy(mem, instruction_stream.data, instruction_stream.size);
/* typecast memory to a function pointer and call the dynamically created executable code */
void (*hq9p_program) (fn_printf) = mem;
hq9p_program(printf);
/* clear up */
munmap(mem, instruction_stream.size);
vector_destroy(&instruction_stream);
exit(EXIT_SUCCESS);
}