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lexer.c
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lexer.c
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/*---------------------------------------------------------------------------------------------
Group #28
2016B5A70607P Manan Agarwal
2015B5A70614P Anirudh Buvanesh
2015B4A70824P Anubhav Bansal
2015B4A70716P Aayush Agarwal
2015B4A70636P Ashish Kumar
---------------------------------------------------------------------------------------------*/
#include "lexer.h"
// FILE *fp;
char buffer1[256];
char buffer2[256];
char lexeme_buffer[20]; //lexeme that is passed to tokenizer
int eof_buffer = 0; //buffer that has EOF
int eof_marker = -1; //position of EOF in the buffer
int curr_buffer = 1; //active buffer
int buffer_itr = 0; //buffer iterator
int lineNumber = 1;
bool lex_error=false;
bool comment_flag=false; //true means that comment is ongoing
bool comment_flag_flag=false;
bool buffer1_empty = true;
bool buffer2_empty = true;
bool delimiter_flag = false;
bool error_long_id = false;
bool error_long_id_print = false;
bool file_finished = false;
extern int err_count;
char *terminal_map[NUM_T] = {
"RNUM","NUM","ID","INTEGER","REAL","BOOLEAN","OF","ARRAY","START","END","DECLARE","MODULE","DRIVER",
"PROGRAM","GET_VALUE","PRINT","USE","WITH","PARAMETERS","TRUE","FALSE","TAKES","INPUT",
"RETURNS","AND","OR","FOR","IN","SWITCH","CASE","BREAK","DEFAULT","WHILE",
"PLUS","MINUS","DIV","MUL","LT","LE","GE","GT","EQ","NE","DEF","COLON","RANGEOP",
"SEMICOL","COMMA","ASSIGNOP","SQBO","SQBC","BO","BC","COMMENTMARK","DRIVERDEF","DRIVERENDDEF",
"EPS", "DOLLAR", "ENDDEF"
};
char *non_terminal_map[NUM_NT] = {
"program", "moduleDeclarations", "moduleDeclaration", "otherModules", "driverModule", "module",
"ret", "input_plist", "N1", "output_plist", "N2", "dataType", "range_arrays", "type", "moduleDef",
"statements", "statement", "ioStmt", "var", "var_id_num", "boolconstt", "whichID",
"simpleStmt", "assignmentStmt", "whichStmt", "lvalueIDStmt", "lvalueARRStmt", "index",
"moduleReuseStmt", "optional", "idList", "N3", "expression", "u1", "new_NT", "unary_op", "arithmeticOrBooleanExpr",
"N7", "AnyTerm", "N8", "arithmeticExpr", "N4", "op1", "term", "N5", "op2", "factor", "logicalOp", "relationalOp",
"declareStmt", "conditionalStmt", "caseStmts", "N9", "value", "default", "iterativeStmt", "range"
};
char *keyword_map[NUM_KEYWORD] = {
"integer", "real", "boolean", "of", "array", "start", "end", "declare", "module", "driver", "program",
"get_value", "print", "use", "with", "parameters", "true", "false", "takes", "input",
"returns", "AND", "OR", "for", "in", "switch", "case", "break", "default", "while"
};
unsigned long hash(char *sym){
const int p = 53;
unsigned long hash = 0;
unsigned long power = 1;
int i = 0;
while(sym[i] != '\0')
{
hash = (hash + (sym[i] - 'a' +1) * power) % HASH_TABLE_SIZE;
power= (power *p) % HASH_TABLE_SIZE;
i++;
}
return hash;
}
unsigned long keyword_hash(char *sym){
const int p = 53; // because both lower and uppercase letters are present
unsigned long hash = 0;
unsigned long power = 1;
int i = 0;
while(sym[i] != '\0')
{
hash = (hash + (sym[i] - 'a' +1) * power) % KEYWORD_HASH_TABLE_SIZE;
power= (power *p) % KEYWORD_HASH_TABLE_SIZE;
i++;
}
return hash;
}
void populate_table(){
char temp1[MAX_LEN], temp2[MAX_LEN];
//Inserting terminals into hash table
int ct1 = 0, ct2 = 0;
for(int term = 0; term < NUM_T ; term++)
{
unsigned long pos_in_table = hash(terminal_map[term]);
NODE *n = (NODE *)malloc(sizeof(NODE));
n->is_terminal = 1;
n->next = m[pos_in_table].head;
(n->s).t = ct1;
m[pos_in_table].head = n;
m[pos_in_table].size++;
ct1++;
}
for(int non_term = 0; non_term < NUM_NT ; non_term++)
{
unsigned long pos_in_table = hash(non_terminal_map[non_term]);
NODE *n = (NODE *)malloc(sizeof(NODE));
n->is_terminal = 0;
n->next = m[pos_in_table].head;
(n->s).nt = (NonTerminals)ct2;
m[pos_in_table].head = n;
m[pos_in_table].size++;
ct2++;
}
}
void populate_keyword_table(){
for(int keyword_no = 0; keyword_no < NUM_KEYWORD; keyword_no ++){
unsigned long pos_in_table = keyword_hash(keyword_map[keyword_no]);
KEYWORD_NODE *the_keyword = (KEYWORD_NODE *)malloc(sizeof(KEYWORD_NODE));
the_keyword->keyword_pos = keyword_no;
the_keyword->next = keys[pos_in_table].head;
keys[pos_in_table].head = the_keyword;
keys[pos_in_table].size++;
}
}
NODE string_to_enum(char* input)
{
Symbol s1;
NODE h1;
unsigned long pos = hash(input);
NODE *h = m[pos].head;
while(h!=NULL) //loop over all collisions
{
if(h->is_terminal)
{
if(strcmp(input ,terminal_map[(h->s).t]) == 0)
{
h1.is_terminal = 1;
h1.s = h->s;
return h1;
}
}
else
{
if(strcmp(input ,non_terminal_map[(h->s).nt]) == 0)
{
h1.is_terminal = 0;
h1.s = h->s;
return h1;
}
}
h = h->next;
}
return h1;
}
NODE is_keyword(char *input){
char getting_token[30];
unsigned long pos = keyword_hash(input);
KEYWORD_NODE *h = keys[pos].head;
NODE ans;
int found = 0;
while(h != NULL){
if(strcmp(input, keyword_map[h->keyword_pos]) == 0){
int i = 0;
while(input[i] != '\0'){
getting_token[i] = input[i];
if(input[i] >= 'a' && input[i] <= 'z'){
getting_token[i] = (input[i] - 32);
}
i++;
}
getting_token[i] = '\0';
ans = string_to_enum(getting_token);
return ans;
}
h = h->next;
}
ans.is_terminal = -1;
return ans;
}
tokenInfo* tokenize(char *str){//str denotes the line for which i have to give the token
int i=0;//important variable
// i has to be maintained for next token
char ch;//parsing the string and used in switch
lex_error=false; //true when lexecal error is encountered
comment_flag_flag = false; //true only when the lexeme is "**"
delimiter_flag = false;
tokenInfo *ans = (tokenInfo*)malloc(sizeof(tokenInfo));//the one I will be returning in get_Token()
int k=0; //initialsing lexeme to null
for(k=0; k<30;k++){
ans->lexeme[k] = '\0';
}
ch=str[0];
ans->line_number=lineNumber;
while(ch!='\0'){
if(ch=='\n'){
lineNumber++;
ans->line_number=lineNumber;
i++;
ch = str[i];
delimiter_flag=true;
error_long_id = false;
break;
}
else if(ch==' ' || ch=='\t'){
i++;
ch = str[i];
delimiter_flag=true;
error_long_id = false;
break;
}
else if((ch>='a' && ch<='z') || (ch>='A' && ch<='Z') || (error_long_id == true && ((ch == '_' ) || (ch>='0' && ch<='9')))){
char temp_lex[30];
int k;
for(k=0;k<30;k++)
temp_lex[k]='\0';
temp_lex[0]=ch;
int j=1;
i++;
ch=str[i];
while((ch>='a' && ch<='z') || (ch>='A' && ch<='Z') || (ch>='0' && ch<='9') || (ch == '_')){
temp_lex[j]=ch;
j++;
if(j==21){
error_long_id = true;
j=20;
break;
}
i++;
ch=str[i];
}
for(k=0;k<j;k++){
ans->lexeme[k]=temp_lex[k];
}
ans->lexeme[k]='\0';
if(error_long_id){
lex_error=true;
break;
}
if(j>20){
strcpy(ans->lexeme,temp_lex);
lex_error=true;
}
NODE keyword_info;
keyword_info = is_keyword(ans->lexeme);
if(keyword_info.is_terminal!=-1){
ans->Token = keyword_info.s.t;
}
else{
ans->Token=T_ID;
}
}
else if(ch>='0' && ch<='9'){
char temp_lex[30];
int k;
for(k=0;k<30;k++)
temp_lex[k]='\0';
temp_lex[0]=ch;
int j=1;
i++;
ch=str[i];
while(ch>='0' && ch<='9'){
temp_lex[j]=ch;
j++;
i++;
ch=str[i];
}
if(ch=='.'){
temp_lex[j]=ch;
i++;
j++;
ch=str[i];
if(ch>='0' && ch<='9'){
temp_lex[j]=ch;
j++;
i++;
ch=str[i];
while(ch>='0' && ch<='9'){
temp_lex[j]=ch;
i++;
j++;
ch=str[i];
}
if(ch=='e' || ch=='E'){
temp_lex[j]=ch;
j++;
i++;
ch=str[i];
if(ch>='0' && ch<='9'){
temp_lex[j]=ch;
j++;i++;
ch=str[i];
while(ch>='0' && ch<='9'){
temp_lex[j]=ch;
j++;i++;
ch=str[i];
}
strcpy(ans->lexeme,temp_lex);
ans->Token=T_RNUM;
}
else{
//+-
if(ch=='+' || ch=='-'){
temp_lex[j]=ch;
j++;i++;
ch=str[i];
if(ch>='0' && ch<='9'){
temp_lex[j]=ch;
j++;i++;
ch=str[i];
while(ch>='0' && ch<='9'){
temp_lex[j]=ch;
j++;i++;
ch=str[i];
}
strcpy(ans->lexeme,temp_lex);
ans->Token=T_RNUM;
}
else{
strcpy(ans->lexeme,temp_lex);
lex_error=true;
}
}
else{
strcpy(ans->lexeme,temp_lex);
lex_error=true;
}
}
}
else{
strcpy(ans->lexeme,temp_lex);
ans->Token=T_RNUM;
}
}
else{
if(ch=='.'){
int k=0;
for(k=0;k<j-1;k++)
ans->lexeme[k]=temp_lex[k];
ans->Token=T_NUM;
i=i-1;
}
else{
strcpy(ans->lexeme,temp_lex);
lex_error=true;
}
}
}
else{
strcpy(ans->lexeme,temp_lex);
ans->Token=T_NUM;
}
}
else if(!((ch>='a' && ch<='z') || (ch>='A' && ch<='Z') || (ch>='0' && ch<='9'))){
error_long_id = false;
switch(ch){
case '+':{
strcpy(ans->lexeme,"+");
ans->Token=T_PLUS;
i+=1;
break;
}
case '-':{
strcpy(ans->lexeme,"-");
ans->Token=T_MINUS;
i+=1;
break;
}
case ';':{
strcpy(ans->lexeme,";");
ans->Token=T_SEMICOL;
i+=1;
break;
}
case ',':{
strcpy(ans->lexeme,",");
ans->Token=T_COMMA;
i+=1;
break;
}
case '=':{
if(i+1<strlen(str) && str[i+1]=='='){
strcpy(ans->lexeme,"==");
ans->Token=T_EQ;
i+=2;
}
else
{
strcpy(ans->lexeme,"=");
lex_error=true;
i+=1;
}
break;
}
case '<':{
if(i+1<strlen(str) && str[i+1]=='<'){
if(i+2<strlen(str) && str[i+2]=='<'){
strcpy(ans->lexeme,"<<<");
ans->Token=T_DRIVERDEF;
i+=3;
}
else{
strcpy(ans->lexeme,"<<");
ans->Token=T_DEF;
i+=2;
}
}
else if(i+1<strlen(str) && str[i+1]=='='){
strcpy(ans->lexeme,"<=");
ans->Token=T_LE;
i+=2;
}
else{
strcpy(ans->lexeme,"<");
ans->Token=T_LT;
i+=1;
}
break;
}
case '>':{
if(i+1<strlen(str) && str[i+1]=='>'){
if(i+2<strlen(str) && str[i+2]=='>'){
strcpy(ans->lexeme,">>>");
ans->Token=T_DRIVERENDDEF;
i+=3;
}
else{
strcpy(ans->lexeme,">>");
ans->Token=T_ENDDEF;
i+=2;
}
}
else if(i+1<strlen(str) && str[i+1]=='='){
strcpy(ans->lexeme,">=");
ans->Token=T_GE;
i+=2;
}
else{
strcpy(ans->lexeme,">");
ans->Token=T_GT;
i+=1;
}
break;
}
case '*':{
if(i+1<strlen(str) && str[i+1]!='*'){
strcpy(ans->lexeme,"*");
ans->Token=T_MUL;
i+=1;
}
else if(i+1<strlen(str) && str[i+1]=='*'){
i+=2;
comment_flag_flag = true;
if(comment_flag==false){
comment_flag = true;
}
else{
comment_flag = false;
}
}
break;
}
case ':':{
if(i+1<strlen(str) && str[i+1]=='='){
strcpy(ans->lexeme,":=");
ans->Token=T_ASSIGNOP;
i+=2;
}
else{
strcpy(ans->lexeme,":");
ans->Token=T_COLON;
i+=1;
}
break;
}
case '.':{
if(i+1<strlen(str) && str[i+1]=='.'){
strcpy(ans->lexeme,"..");
ans->Token=T_RANGEOP;
i+=2;
}
else{
strcpy(ans->lexeme,".");
lex_error=true;
i+=1;
}
break;
}
case '!':{
if(i+1<strlen(str) && str[i+1]=='='){
strcpy(ans->lexeme,"!=");
ans->Token=T_NE;
i+=2;
}
else{
strcpy(ans->lexeme,"!");
lex_error=true;
i+=1;
}
break;
}
case ']':{
strcpy(ans->lexeme,"]");
ans->Token=T_SQBC;
i+=1;
break;
}
case '[':{
strcpy(ans->lexeme,"[");
ans->Token=T_SQBO;
i+=1;
break;
}
case '(':{
strcpy(ans->lexeme,"(");
ans->Token=T_BO;
i+=1;
break;
}
case ')':{
strcpy(ans->lexeme,")");
ans->Token=T_BC;
i+=1;
break;
}
case '/':{
strcpy(ans->lexeme,"/");
ans->Token=T_DIV;
i+=1;
break;
}
default:{
sprintf(ans->lexeme,"%c",ch);
lex_error=true;
i+=1;
break;
}
}
}
break;
}
buffer_itr += i;
return(ans);
}
void getstream(){
char ch;
if(buffer1_empty == true && eof_buffer==0){
int itr = 0;
while (itr<256 && (ch = fgetc(fp)) != EOF)
{
buffer1[itr] = ch;
itr++;
}
if(itr!=256){
eof_marker = itr;
eof_buffer = 1;
}
buffer1_empty = false;
}
if(buffer2_empty == true && eof_buffer==0){
int itr = 0;
while (itr<256 && (ch = fgetc(fp)) != EOF)
{
buffer2[itr] = ch;
itr++;
}
if(itr!=256){
eof_marker = itr;
eof_buffer = 2;
}
buffer2_empty = false;
}
if(buffer_itr > 256-1){
buffer_itr-=256;
if(curr_buffer == 1){
curr_buffer = 2;
buffer1_empty = true;
}
else if(curr_buffer == 2){
curr_buffer =1;
buffer2_empty = true;
}
}
if(curr_buffer == 1){
int i=0;
while(i<21){
if((eof_buffer == 1 && (buffer_itr+i>=eof_marker)) || (eof_buffer == 2 && (buffer_itr+i-256>=eof_marker))){
lexeme_buffer[i] = '\0';
}
else if(buffer_itr+i<256){
lexeme_buffer[i] = buffer1[buffer_itr+i];
}
else{
lexeme_buffer[i] = buffer2[buffer_itr+i-256];
}
i++;
}
}
else if(curr_buffer == 2){
int i=0;
while(i<21){
if((eof_buffer == 2 && (buffer_itr+i>=eof_marker)) || (eof_buffer == 1 && (buffer_itr+i-256>=eof_marker))){
lexeme_buffer[i] = '\0';
}
else if(buffer_itr+i<256){
lexeme_buffer[i] = buffer2[buffer_itr+i];
}
else{
lexeme_buffer[i] = buffer1[buffer_itr+i-256];
}
i++;
}
}
}
tokenInfo* getNextToken(){
tokenInfo *a = (tokenInfo *)malloc(sizeof(tokenInfo));
if(curr_buffer == eof_buffer && buffer_itr>=eof_marker){
if(comment_flag==true){
printf("\nLexical Error because end of comment not found");
}
else{
printf("\nEOF reached");
}
printf("\nTerminating Lexer\n");
file_finished = true;
a->Token = T_DOLLAR;
strcpy(a->lexeme, "DOLLAR");
}
else{
getstream();
a = tokenize(lexeme_buffer); //NOTE: line number will be taken care of in anubhav
if(comment_flag==true || comment_flag_flag==true || delimiter_flag==true){
a = getNextToken();
}
else if(lex_error){
if(error_long_id==true){
if(error_long_id_print == false){
error_long_id_print = true;
printf("\nLine Number %d Lexeme Error Lexeme %s",a->line_number,a->lexeme);
err_count+=1;
}
else{
printf("%s",a->lexeme);
}
}
else{
error_long_id_print = false;
printf("\nLine Number %d Lexeme Error Lexeme %s",a->line_number,a->lexeme);
err_count+=1;
}
a = getNextToken();
}
else{
return a;
}
}
return a;
}
void removeComments(char *testcaseFile, char *cleanFile){
FILE *fp_test = fopen(testcaseFile, "r");
FILE *fp_clean = fopen(cleanFile, "w");
if (fp_test == NULL)
{
printf("File is not available \n");
}
int match = 0;
char ch1, ch2;
while(1){
ch1 = fgetc(fp_test);
if(ch1 == EOF)
break;
//if I find a new line or I am outside a comment
if(ch1 == '\n' || (ch1 != '*' && match == 0))
fputc(ch1, fp_clean);
//if character I find is a '*'
else if(ch1 == '*'){
ch2 = fgetc(fp_test);
if(ch2 != '*' && match == 0)
fputc(ch1, fp_clean);
if(ch2 == EOF)
break;
//I get a new line and am outside a comment
if(ch2 == '\n' || (ch2 != '*' && match == 0))
fputc(ch2, fp_clean);
else if(ch2 == '*' && match == 0)
match = 1;
else if(ch2 == '*' && match == 1)
match = 0;
}
}
fclose(fp_test);
fclose(fp_clean);
}
void printTokens(char *filename){
populate_table();
populate_keyword_table();
fp = fopen(filename, "r");
if (fp == NULL)
{
printf("File is not available \n");
}
tokenInfo *a;
while(1){
a = getNextToken();
if(file_finished!=true){
printf("\n\n%d ",a->line_number);
printf("%s ", a->lexeme);
printf("%s", terminal_map[a->Token]);
}
else{
break;
}
}
fclose(fp);
}