Incercare lab5, lexical analiser, CT

#include<stdio.h>
#include<stdlib.h>
#include<errno.h>
#include<ctype.h>
#include<stdarg.h>
#include<string.h>
#define SAFEALLOC(var,Type) if((var=(Type*)malloc(sizeof(Type)))==NULL) err("not enough memory");
int line;
const char *pCrtCh;

enum{
    ID, END,
    //constants
    CT_INT, CT_REAL, CT_CHAR, CT_STRING,
    //keywords
    BREAK, CHAR, DOUBLE, ELSE, FOR, IF, INT, RETURN, STRUCT, VOID, WHILE,
    //delimiters
    COMMA, SEMICOLON, LPAR, RPAR, LBRACKET, RBRACKET, LACC, RACC,
    //operators
    ADD, SUB, MUL, DIV, DOT, AND, OR, NOT, ASSIGN, EQUAL, NOTEQ, LESS, LESSEQ, GREATER, GREATEREQ,
    SPACE, LINECOMMENT, COMMENT
}; //tokens codes

typedef struct _Token{
  int code; // code (name)
  union{
    char *text; //  used for ID, CT_STRING(dynamically allocated )
    long  int  i;  //  used   for CT_INT, CT_CHAR
    double r;//  used for   CT_REAL
  };
  int line; // the input file line
  struct _Token *next; // link to the next token
}Token;

void err(const char *fmt,...)
{
  va_list va;
  va_start(va,fmt);
  fprintf(stderr,"error: ");
  vfprintf(stderr,fmt,va);
  fputc('\n',stderr);
  va_end(va);
  exit(-1);
}

Token *lastToken, *tokens;

Token *addTk(int code)
{
  Token *tk;
  SAFEALLOC(tk,Token);
  tk->code=code;
  tk->line=line;
  tk->next=NULL;
  if(lastToken){
    lastToken->next=tk;
  }else{
      tokens=tk;
  }
  lastToken=tk;
  return tk;
}


void tkerr (const Token *tk, const char *fmt,...)
{
  va_list va;
  va_start(va,fmt);
  fprintf(stderr,"error in line %d:", tk->line);
  vfprintf(stderr,fmt,va);
  fputc('\n', stderr);
  va_end(va);
  exit(-1);
}

char* createString(const char *s1, const char *s2)
{
  char *result = malloc(strlen(s1)+strlen(s2)+1);//+1 for the zero-terminator
  strcpy(result, s1);
  strcat(result, s2);
  return result;
}

int getNextToken()
{
  int state=0, nCh;
  char ch;
  const char *pStartCh;
  Token *tk;

  while(1)
  {
   ch=*pCrtCh;
   printf("state: %d, character:%c\n",state,ch);
   switch(state)
   {
     case 0:
       if(ch==' '||ch=='\r'||ch=='\t')
       {
     pCrtCh++; // consume the characterand remains in state 0
       }
       else if(ch=='\n')//handled separately in order to update the current line
       {
     line++;
     pCrtCh++;
       }
       else if(ch>='1' || ch<='9')
       {
     pCrtCh++;
     state=1;
       }
       else if(ch=='0')
       {
     pCrtCh++;
     state=2;
       }
       else if(ch==0) //the end of the input string
       {
     addTk(END);
     return END;
       }
       else tkerr(addTk(END),"invalid character");
       break;

     case 1:
       while(ch>='0'&&ch<='9') pCrtCh++;
       state=3;//CT INT
       break;

     case 2:
       pStart=pCrtCh;
       pCrtCh++;
       state=3;
       break;

     case 3:
       while(ch>='0'&&ch<='7') pCrtCh++;
       state=4;
     /*case 2:
       nCh=pCrtCh-pStartCh;//the id length
       //keywords tests
       if(nCh==5&&!memcmp(pStartCh,"break",5))tk=addTk(BREAK);
       else if(nCh==4&&!memcmp(pStartCh,"char",4))tk=addTk(CHAR);
       //...all keywords...
       else //if no keyword, then it is an ID
       {
     tk=addTk(ID);
     tk->text=createString(pStartCh,pCrtCh);
       }
       return tk->code;
     */
     case 48:
    if(ch=='=')
    {
      pCrtCh++;
      state=49;
    }
    else state = 50;
    break;

     case 49:
       addTk(ASSIGN);
       return ASSIGN;

     case 50:
       addTk(EQUAL);
       return EQUAL;



   }

  }
}

void printTokens()
{
    Token *current=tokens;
    while(current!=NULL)
    {
        printf("%i", current->code);
        switch(current->code)
        {
            case ID:
            case CT_STRING:
                printf(":%s",current->text);
                break;
            case CT_CHAR:
                printf(":%c",(int)current->i);
                break;
            case CT_INT:
                printf(":%li",current->i);
                break;
            case CT_REAL:
                printf(":%lf",current->r);
                break;
        }
        printf(" ");
        current=current->next;
    }
    printf("\n");
}

void getTokens()
{
    do
    {
        getNextToken();
    }while(*pCrtCh);
}

int main(void)
{
  getTokens();
  printTokens();

  return 0;
}