/* Ragel State Machine for tokenizing text */
#include <stdio.h>
#include <string.h>
#include <apc/parser.tab.h>

extern void lexer_pushtok(int, YYSTYPE);

int lexer_lex(const char*);
int ipow(int, int);
int ttov(const char* str, int);
uint64_t ttor(const char* str, int);
char* ttos(const char* str, int);


#define MAX_TOK_LEN 64
#define MAX_TOKENS 16
#define MAX_STR_SIZE (MAX_TOK_LEN * MAX_TOKENS)


%%{
  machine token_matcher;

  # set up yylval and tok_t to be pushed to stack
  action set_ref {
                   tok_t = REF;                      \
                   yylval.ref = ttor(ts, p-ts);      \
                   lexer_pushtok(tok_t, yylval);     \
                   num_tokens++; }

  action set_val { tok_t = NUM;                      \
                   yylval.val = ttov(ts, p-ts);      \
                   lexer_pushtok(tok_t, yylval);     \
                   num_tokens++; }

  action set_name { tok_t = NAME;                    \
                    yylval.str = ttos(ts, p-ts);     \
                    lexer_pushtok(tok_t, yylval);    \
                    num_tokens++; }

  action set_ts   { ts = p; }

  # instantiate machines for each possible token
  ref = '0x' xdigit+ %set_ref;
  val = digit+ %set_val;
  name = alpha+ %set_name;
  tok = ref | val | name;
  segment = (tok . '_') %set_ts;

  main := segment* . tok;
}%%


%%write data;

/* Scan filename and push the its tokens
   onto the stack */
int lexer_lex (const char* str)
{
  const char *p, *pe, *ts, *eof;
  int  cs, tok_t, num_tokens; //tok_t == token type

  num_tokens = 0;

  p = ts = str;
  pe = p + strlen(str) + 1;
  %%write init;
  %%write exec;


  printf (str);
  return num_tokens;
}

int ipow(int base, int exp)
{
  int result = 1;
  while (exp)
    {
      if (exp & 1)
        result = result * base;
      exp = exp >> 1;
      base *= base;
    }

  return result;
}

/*  Token to Value */
int ttov(const char* str, int len)
{
  int i, val = 0;

  for (i = 0; i < len; i++)
    {
      val += ((str[len - (i + 1)] - '0') * ipow(10,i));
    }

  return val;
}

uint64_t ttor(const char* str, int len)
{
  int i;
  uint64_t num = 0;

  for (i = 0; i < len; i++)
    {
      num += ((str[len - (i + 1)] - '0') * ipow(10,i));
    }

  return num;
}

char* ttos(const char* str, int len)
{
  int i;
  char token_buf[MAX_TOK_LEN];

  memmove(token_buf, str, len);
  token_buf[len+1] = '\0';

  return strdup(token_buf);
}