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functions.c
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functions.c
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/*
====================================================================================
Name : function.c
Description: This file holds function methods used to process assembly line
====================================================================================
*/
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include "structs.h"
#include "functions.h"
void* allocate_memory(int bytes);
/*
* Description: Allocates a string
* Input: Number of tokens in string
* Output: Allocated string
*/
char* allocate_string(int string_length) {
return (char*)allocate_memory(sizeof(char) * (string_length + 1));
}
/*
* Description: Allocates memory
* Input: Number of bytes to allocate
* Output: Pointer to number
*/
void* allocate_memory(int bytes) {
void* result = (void*)malloc(bytes);
if (result == NULL) {
print_runtime_error("Could not allocate memory. Exit program");
}
return result;
}
/*
* Description: Prints runtime error
* Input: Message
*/
void print_runtime_error(char* message) {
fprintf(stderr, "Error: %s \n", message);
}
/*
* Description: Prints a compiler error to the user
* Input: 1. Message
* 2. Current line
*/
void print_compiler_error(char* message, line_info* info) {
fprintf(stderr, "Error: %s, File %s Line %d \n", message, info->file_name, info->line_number);
}
/*
* Description: Creates a transition data structure
* Output: Basic transition data
*/
transition_data* create_transition_data() {
transition_data* transition = (transition_data*)allocate_memory(sizeof(transition_data));
/* Initialize */
if (transition != NULL) {
transition->IC = 0;
transition->DC = 0;
transition->prev_operation_operand = NULL;
transition->is_compiler_error = false;
transition->is_runtimer_error = false;
transition->current_line_information = NULL;
}
return transition;
}
/*
* Description: Checks if this is an empty line or a comment
* Input: The line to check
* Output: Is this an empty line or a comment
*/
bool is_empty_or_comment(char* line) {
int i;
int length = strlen(line);
/* Check's there is a token that isn't a space */
for (i = 0; i < length; i++) {
if (!isspace(line[i])) {
return line[i] == COMMENT;
}
}
return true;
}
/*
* Description: Creates a line information structure
* Input: 1. File name
* 2. Line number
* 3. Line content
* Output: Pointer to line information
*/
line_info* create_line_info(char* file_name, int line_number, char* line_str) {
line_info* info = (line_info*)allocate_memory(sizeof(line_info));
/* Initialize */
if (info != NULL) {
info->current_index = 0;
info->file_name = file_name;
info->line_number = line_number;
info->line_str = line_str;
info->line_length = strlen(line_str);
}
return info;
}
void skip_all_spaces(line_info* info) {
int index = info->current_index;
/* Scans all spaces */
while ((index < info->line_length) && isspace(info->line_str[index])) {
index++;
}
info->current_index = index;
}
/*
* Description: Checks if the string is a valid label
* Input: String to check
* Output: True if label, otherwise false
*/
bool is_valid_label(char* str) {
int len = strlen(str);
/*
* Make sure that :
* 1) string start's with a letter
* 2) string is shorter then maximum length (excluding the end of label token)
*/
if (!isalpha(str[0]) || len > LABEL_MAX_LENGTH) {
return false;
}
return true;
}
/*
* Description: Read next word from line
* Input: Current transition data
* Output: Extracted word
*/
char* get_next_word(transition_data* transition)
{
char* word;
int i, word_end_index, word_start_index, word_length;
skip_all_spaces(transition->current_line_information);
word_end_index = word_start_index = i = transition->current_line_information->current_index;
/* Find word position */
for (;i < transition->current_line_information->line_length; i++) {
if (!isspace(transition->current_line_information->line_str[i])) {
word_end_index = i;
} else {
break;
}
}
word_length = word_end_index - word_start_index + 1;
word = allocate_string(word_length);
if (word == NULL) {
transition->is_runtimer_error = true;
} else {
/* Copy word */
strncpy(word, transition->current_line_information->line_str + word_start_index, word_length);
(word)[word_length] = END_OF_STRING;
transition->current_line_information->current_index = word_end_index + 1;
}
return word;
}
/*
* Description: Checks if there are tokens that aren't spaces after current index
* Input: Line information
* Output: True if found non-space token, otherwise false
*/
bool is_end_of_data_in_line(line_info* info) {
bool is_end = true;
int i;
/* Searches non-space token */
for (i = info->current_index; i < info->line_length; i++) {
if (!isspace(info->line_str[i])) {
is_end = false;
break;
}
}
return is_end;
}
/*
* Description: Checks if we've reached end of line
* Input: Line information
* Output: True if we've reached end of lines, otherwise false
*/
bool is_end_of_line(line_info* info) {
return info->current_index == info->line_length;
}
/*
* Description: Checks if this is a valid operation line
* Input: 1. Line information
*/
bool is_valid_is_operation_line (line_info* info) {
return info->line_length < OPERATION_LINE_MAX_LENGTH;
}
/*
* Description: Checks if operand is a register
* Input: 1. Operand
* Output: True if register, otherwise false
*/
bool is_register(char* operand) {
int digit;
int length = strlen(operand);
if ((length != 2) || (operand[0] != REGISTER_FIRST_TOKEN) || (!isdigit(operand[1]))) {
return false;
}
digit = atoi(operand + 1);
return (digit < REGISTERS_COUNT) && (digit >= 0);
}
/*
* Description: Creates an output file from given file name
* Input: 1. File name without extension
* 2. File extension
* Output: Reference to created file
*/
FILE* create_output_file(char* file_name_without_extension, char* extension) {
FILE* p_output_file = NULL;
int file_name_length = strlen(file_name_without_extension) + strlen(extension);
char* file_name = allocate_string(file_name_length);
if (file_name != NULL) {
/* Creates code file output name */
strcpy(file_name, file_name_without_extension);
strcat(file_name, extension);
file_name[file_name_length] = END_OF_STRING;
p_output_file = fopen(file_name, WRITE_MODE);
free(file_name);
if (!p_output_file) {
print_runtime_error("Cannot create output file");
}
}
return p_output_file;
}
/*
* Description: Skips the label
* Input: Line information
*/
void skip_label(line_info* info) {
/* Search the label end token */
char* partial_line = strchr(info->line_str, LABEL_END_TOKEN);
if (partial_line != NULL) {
info->current_index = partial_line - info->line_str + 1;
}
}