text: 
  /* Tokenizer implementation */
  
  #include "Python.h"
  #include "pgenheaders.h"
  
  #include <ctype.h>
  #include <assert.h>
  
  #include "tokenizer.h"
  #include "errcode.h"
  
  #include "unicodeobject.h"
  #include "bytesobject.h"
  #include "fileobject.h"
  #include "codecs.h"
  #include "abstract.h"
  
  /* Alternate tab spacing */
  #define ALTTABSIZE 1
  
  #define is_potential_identifier_start(c) (\
                (c >= 'a' && c <= 'z')\
                 || (c >= 'A' && c <= 'Z')\
                 || c == '_'\
                 || (c >= 128))
  
  #define is_potential_identifier_char(c) (\
                (c >= 'a' && c <= 'z')\
                 || (c >= 'A' && c <= 'Z')\
                 || (c >= '0' && c <= '9')\
                 || c == '_'\
                 || (c >= 128))
  
  extern char *PyOS_Readline(FILE *, FILE *, const char *);
  /* Return malloc'ed string including trailing \n;
     empty malloc'ed string for EOF;
     NULL if interrupted */
  
  /* Don't ever change this -- it would break the portability of Python code */
  #define TABSIZE 8
  
  /* Forward */
  static struct tok_state *tok_new(void);
  static int tok_nextc(struct tok_state *tok);
  static void tok_backup(struct tok_state *tok, int c);
  
  
  /* Spaces in this constant are treated as "zero or more spaces or tabs" when
     tokenizing. */
  static const char* type_comment_prefix = "# type: ";
  
  /* Create and initialize a new tok_state structure */
  
  static struct tok_state *
  tok_new(void)
  {
      struct tok_state *tok = (struct tok_state *)PyMem_MALLOC(
                                              sizeof(struct tok_state));
      if (tok == NULL)
          return NULL;
      tok->buf = tok->cur = tok->end = tok->inp = tok->start = NULL;
      tok->done = E_OK;
      tok->fp = NULL;
      tok->input = NULL;
      tok->tabsize = TABSIZE;
      tok->indent = 0;
      tok->indstack[0] = 0;
  
      tok->atbol = 1;
      tok->pendin = 0;
      tok->prompt = tok->nextprompt = NULL;
      tok->lineno = 0;
      tok->level = 0;
      tok->altindstack[0] = 0;
      tok->decoding_state = STATE_INIT;
      tok->decoding_erred = 0;
      tok->read_coding_spec = 0;
      tok->enc = NULL;
      tok->encoding = NULL;
      tok->cont_line = 0;
      tok->filename = NULL;
      tok->decoding_readline = NULL;
      tok->decoding_buffer = NULL;
      tok->type_comments = 0;
  
      return tok;
  }
  
  static char *
  new_string(const char *s, Py_ssize_t len, struct tok_state *tok)
  {
      char* result = (char *)PyMem_MALLOC(len + 1);
      if (!result) {
          tok->done = E_NOMEM;
          return NULL;
      }
      memcpy(result, s, len);
      result[len] = '\0';
      return result;
  }
  
  static char *
  error_ret(struct tok_state *tok) /* XXX */
  {
      tok->decoding_erred = 1;
      if (tok->fp != NULL && tok->buf != NULL) /* see PyTokenizer_Free */
          PyMem_FREE(tok->buf);
      tok->buf = tok->cur = tok->end = tok->inp = tok->start = NULL;
      tok->done = E_DECODE;
      return NULL;                /* as if it were EOF */
  }
  
  
  static const char *
  get_normal_name(const char *s)  /* for utf-8 and latin-1 */
  {
      char buf[13];
      int i;
      for (i = 0; i < 12; i++) {
          int c = s[i];
          if (c == '\0')
              break;
          else if (c == '_')
              buf[i] = '-';
          else
              buf[i] = tolower(c);
      }
      buf[i] = '\0';
      if (strcmp(buf, "utf-8") == 0 ||
          strncmp(buf, "utf-8-", 6) == 0)
          return "utf-8";
      else if (strcmp(buf, "latin-1") == 0 ||
               strcmp(buf, "iso-8859-1") == 0 ||
               strcmp(buf, "iso-latin-1") == 0 ||
               strncmp(buf, "latin-1-", 8) == 0 ||
               strncmp(buf, "iso-8859-1-", 11) == 0 ||
               strncmp(buf, "iso-latin-1-", 12) == 0)
          return "iso-8859-1";
      else
          return s;
  }
  
  /* Return the coding spec in S, or NULL if none is found.  */
  
  static int
  get_coding_spec(const char *s, char **spec, Py_ssize_t size, struct tok_state *tok)
  {
      Py_ssize_t i;
      *spec = NULL;
      /* Coding spec must be in a comment, and that comment must be
       * the only statement on the source code line. */
      for (i = 0; i < size - 6; i++) {
          if (s[i] == '#')
              break;
          if (s[i] != ' ' && s[i] != '\t' && s[i] != '\014')
              return 1;
      }
      for (; i < size - 6; i++) { /* XXX inefficient search */
          const char* t = s + i;
          if (strncmp(t, "coding", 6) == 0) {
              const char* begin = NULL;
              t += 6;
              if (t[0] != ':' && t[0] != '=')
                  continue;
              do {
                  t++;
              } while (t[0] == '\x20' || t[0] == '\t');
  
              begin = t;
              while (Py_ISALNUM(t[0]) ||
                     t[0] == '-' || t[0] == '_' || t[0] == '.')
                  t++;
  
              if (begin < t) {
                  char* r = new_string(begin, t - begin, tok);
                  const char* q;
                  if (!r)
                      return 0;
                  q = get_normal_name(r);
                  if (r != q) {
                      PyMem_FREE(r);
                      r = new_string(q, strlen(q), tok);
                      if (!r)
                          return 0;
                  }
                  *spec = r;
                  break;
              }
          }
      }
      return 1;
  }
  
  /* Check whether the line contains a coding spec. If it does,
     invoke the set_readline function for the new encoding.
     This function receives the tok_state and the new encoding.
     Return 1 on success, 0 on failure.  */
  
  static int
  check_coding_spec(const char* line, Py_ssize_t size, struct tok_state *tok,
                    int set_readline(struct tok_state *, const char *))
  {
      char *cs;
      int r = 1;
  
      if (tok->cont_line) {
          /* It's a continuation line, so it can't be a coding spec. */
          tok->read_coding_spec = 1;
          return 1;
      }
      if (!get_coding_spec(line, &cs, size, tok))
          return 0;
      if (!cs) {
          Py_ssize_t i;
          for (i = 0; i < size; i++) {
              if (line[i] == '#' || line[i] == '\n' || line[i] == '\r')
                  break;
              if (line[i] != ' ' && line[i] != '\t' && line[i] != '\014') {
                  /* Stop checking coding spec after a line containing
                   * anything except a comment. */
                  tok->read_coding_spec = 1;
                  break;
              }
          }
          return 1;
      }
      tok->read_coding_spec = 1;
      if (tok->encoding == NULL) {
          assert(tok->decoding_state == STATE_RAW);
          if (strcmp(cs, "utf-8") == 0) {
              tok->encoding = cs;
          } else {
              r = set_readline(tok, cs);
              if (r) {
                  tok->encoding = cs;
                  tok->decoding_state = STATE_NORMAL;
              }
              else {
                  PyErr_Format(PyExc_SyntaxError,
                               "encoding problem: %s", cs);
                  PyMem_FREE(cs);
              }
          }
      } else {                /* then, compare cs with BOM */
          r = (strcmp(tok->encoding, cs) == 0);
          if (!r)
              PyErr_Format(PyExc_SyntaxError,
                           "encoding problem: %s with BOM", cs);
          PyMem_FREE(cs);
      }
      return r;
  }
  
  /* See whether the file starts with a BOM. If it does,
     invoke the set_readline function with the new encoding.
     Return 1 on success, 0 on failure.  */
  
  static int
  check_bom(int get_char(struct tok_state *),
            void unget_char(int, struct tok_state *),
            int set_readline(struct tok_state *, const char *),
            struct tok_state *tok)
  {
      int ch1, ch2, ch3;
      ch1 = get_char(tok);
      tok->decoding_state = STATE_RAW;
      if (ch1 == EOF) {
          return 1;
      } else if (ch1 == 0xEF) {
          ch2 = get_char(tok);
          if (ch2 != 0xBB) {
              unget_char(ch2, tok);
              unget_char(ch1, tok);
              return 1;
          }
          ch3 = get_char(tok);
          if (ch3 != 0xBF) {
              unget_char(ch3, tok);
              unget_char(ch2, tok);
              unget_char(ch1, tok);
              return 1;
          }
  #if 0
      /* Disable support for UTF-16 BOMs until a decision
         is made whether this needs to be supported.  */
      } else if (ch1 == 0xFE) {
          ch2 = get_char(tok);
          if (ch2 != 0xFF) {
              unget_char(ch2, tok);
              unget_char(ch1, tok);
              return 1;
          }
          if (!set_readline(tok, "utf-16-be"))
              return 0;
          tok->decoding_state = STATE_NORMAL;
      } else if (ch1 == 0xFF) {
          ch2 = get_char(tok);
          if (ch2 != 0xFE) {
              unget_char(ch2, tok);
              unget_char(ch1, tok);
              return 1;
          }
          if (!set_readline(tok, "utf-16-le"))
              return 0;
          tok->decoding_state = STATE_NORMAL;
  #endif
      } else {
          unget_char(ch1, tok);
          return 1;
      }
      if (tok->encoding != NULL)
          PyMem_FREE(tok->encoding);
      tok->encoding = new_string("utf-8", 5, tok);
      if (!tok->encoding)
          return 0;
      /* No need to set_readline: input is already utf-8 */
      return 1;
  }
  
  /* Read a line of text from TOK into S, using the stream in TOK.
     Return NULL on failure, else S.
  
     On entry, tok->decoding_buffer will be one of:
       1) NULL: need to call tok->decoding_readline to get a new line
       2) PyUnicodeObject *: decoding_feof has called tok->decoding_readline and
         stored the result in tok->decoding_buffer
       3) PyByteArrayObject *: previous call to fp_readl did not have enough room
         (in the s buffer) to copy entire contents of the line read
         by tok->decoding_readline.  tok->decoding_buffer has the overflow.
         In this case, fp_readl is called in a loop (with an expanded buffer)
         until the buffer ends with a '\n' (or until the end of the file is
         reached): see tok_nextc and its calls to decoding_fgets.
  */
  
  static char *
  fp_readl(char *s, int size, struct tok_state *tok)
  {
      PyObject* bufobj;
      const char *buf;
      Py_ssize_t buflen;
  
      /* Ask for one less byte so we can terminate it */
      assert(size > 0);
      size--;
  
      if (tok->decoding_buffer) {
          bufobj = tok->decoding_buffer;
          Py_INCREF(bufobj);
      }
      else
      {
          bufobj = _PyObject_CallNoArg(tok->decoding_readline);
          if (bufobj == NULL)
              goto error;
      }
      if (PyUnicode_CheckExact(bufobj))
      {
          buf = PyUnicode_AsUTF8AndSize(bufobj, &buflen);
          if (buf == NULL) {
              goto error;
          }
      }
      else
      {
          buf = PyByteArray_AsString(bufobj);
          if (buf == NULL) {
              goto error;
          }
          buflen = PyByteArray_GET_SIZE(bufobj);
      }
  
      Py_XDECREF(tok->decoding_buffer);
      if (buflen > size) {
          /* Too many chars, the rest goes into tok->decoding_buffer */
          tok->decoding_buffer = PyByteArray_FromStringAndSize(buf+size,
                                                           buflen-size);
          if (tok->decoding_buffer == NULL)
              goto error;
          buflen = size;
      }
      else
          tok->decoding_buffer = NULL;
  
      memcpy(s, buf, buflen);
      s[buflen] = '\0';
      if (buflen == 0) /* EOF */
          s = NULL;
      Py_DECREF(bufobj);
      return s;
  
  error:
      Py_XDECREF(bufobj);
      return error_ret(tok);
  }
  
  /* Set the readline function for TOK to a StreamReader's
     readline function. The StreamReader is named ENC.
  
     This function is called from check_bom and check_coding_spec.
  
     ENC is usually identical to the future value of tok->encoding,
     except for the (currently unsupported) case of UTF-16.
  
     Return 1 on success, 0 on failure. */
  
  static int
  fp_setreadl(struct tok_state *tok, const char* enc)
  {
      PyObject *readline, *io, *stream;
      _Py_IDENTIFIER(open);
      _Py_IDENTIFIER(readline);
      int fd;
      long pos;
  
      fd = fileno(tok->fp);
      /* Due to buffering the file offset for fd can be different from the file
       * position of tok->fp.  If tok->fp was opened in text mode on Windows,
       * its file position counts CRLF as one char and can't be directly mapped
       * to the file offset for fd.  Instead we step back one byte and read to
       * the end of line.*/
      pos = ftell(tok->fp);
      if (pos == -1 ||
          lseek(fd, (off_t)(pos > 0 ? pos - 1 : pos), SEEK_SET) == (off_t)-1) {
          PyErr_SetFromErrnoWithFilename(PyExc_OSError, NULL);
          return 0;
      }
  
      io = PyImport_ImportModuleNoBlock("io");
      if (io == NULL)
          return 0;
  
      stream = _PyObject_CallMethodId(io, &PyId_open, "isisOOO",
                      fd, "r", -1, enc, Py_None, Py_None, Py_False);
      Py_DECREF(io);
      if (stream == NULL)
          return 0;
  
      readline = _PyObject_GetAttrId(stream, &PyId_readline);
      Py_DECREF(stream);
      if (readline == NULL)
          return 0;
      Py_XSETREF(tok->decoding_readline, readline);
  
      if (pos > 0) {
          PyObject *bufobj = _PyObject_CallNoArg(readline);
          if (bufobj == NULL)
              return 0;
          Py_DECREF(bufobj);
      }
  
      return 1;
  }
  
  /* Fetch the next byte from TOK. */
  
  static int fp_getc(struct tok_state *tok) {
      return getc(tok->fp);
  }
  
  /* Unfetch the last byte back into TOK.  */
  
  static void fp_ungetc(int c, struct tok_state *tok) {
      ungetc(c, tok->fp);
  }
  
  /* Check whether the characters at s start a valid
     UTF-8 sequence. Return the number of characters forming
     the sequence if yes, 0 if not.  */
  static int valid_utf8(const unsigned char* s)
  {
      int expected = 0;
      int length;
      if (*s < 0x80)
          /* single-byte code */
          return 1;
      if (*s < 0xc0)
          /* following byte */
          return 0;
      if (*s < 0xE0)
          expected = 1;
      else if (*s < 0xF0)
          expected = 2;
      else if (*s < 0xF8)
          expected = 3;
      else
          return 0;
      length = expected + 1;
      for (; expected; expected--)
          if (s[expected] < 0x80 || s[expected] >= 0xC0)
              return 0;
      return length;
  }
  
  /* Read a line of input from TOK. Determine encoding
     if necessary.  */
  
  static char *
  decoding_fgets(char *s, int size, struct tok_state *tok)
  {
      char *line = NULL;
      int badchar = 0;
      for (;;) {
          if (tok->decoding_state == STATE_NORMAL) {
              /* We already have a codec associated with
                 this input. */
              line = fp_readl(s, size, tok);
              break;
          } else if (tok->decoding_state == STATE_RAW) {
              /* We want a 'raw' read. */
              line = Py_UniversalNewlineFgets(s, size,
                                              tok->fp, NULL);
              break;
          } else {
              /* We have not yet determined the encoding.
                 If an encoding is found, use the file-pointer
                 reader functions from now on. */
              if (!check_bom(fp_getc, fp_ungetc, fp_setreadl, tok))
                  return error_ret(tok);
              assert(tok->decoding_state != STATE_INIT);
          }
      }
      if (line != NULL && tok->lineno < 2 && !tok->read_coding_spec) {
          if (!check_coding_spec(line, strlen(line), tok, fp_setreadl)) {
              return error_ret(tok);
          }
      }
      /* The default encoding is UTF-8, so make sure we don't have any
         non-UTF-8 sequences in it. */
      if (line && !tok->encoding) {
          unsigned char *c;
          int length;
          for (c = (unsigned char *)line; *c; c += length)
              if (!(length = valid_utf8(c))) {
                  badchar = *c;
                  break;
              }
      }
      if (badchar) {
          /* Need to add 1 to the line number, since this line
             has not been counted, yet.  */
          PyErr_Format(PyExc_SyntaxError,
                  "Non-UTF-8 code starting with '\\x%.2x' "
                  "in file %U on line %i, "
                  "but no encoding declared; "
                  "see http://python.org/dev/peps/pep-0263/ for details",
                  badchar, tok->filename, tok->lineno + 1);
          return error_ret(tok);
      }
      return line;
  }
  
  static int
  decoding_feof(struct tok_state *tok)
  {
      if (tok->decoding_state != STATE_NORMAL) {
          return feof(tok->fp);
      } else {
          PyObject* buf = tok->decoding_buffer;
          if (buf == NULL) {
              buf = _PyObject_CallNoArg(tok->decoding_readline);
              if (buf == NULL) {
                  error_ret(tok);
                  return 1;
              } else {
                  tok->decoding_buffer = buf;
              }
          }
          return PyObject_Length(buf) == 0;
      }
  }
  
  /* Fetch a byte from TOK, using the string buffer. */
  
  static int
  buf_getc(struct tok_state *tok) {
      return Py_CHARMASK(*tok->str++);
  }
  
  /* Unfetch a byte from TOK, using the string buffer. */
  
  static void
  buf_ungetc(int c, struct tok_state *tok) {
      tok->str--;
      assert(Py_CHARMASK(*tok->str) == c);        /* tok->cur may point to read-only segment */
  }
  
  /* Set the readline function for TOK to ENC. For the string-based
     tokenizer, this means to just record the encoding. */
  
  static int
  buf_setreadl(struct tok_state *tok, const char* enc) {
      tok->enc = enc;
      return 1;
  }
  
  /* Return a UTF-8 encoding Python string object from the
     C byte string STR, which is encoded with ENC. */
  
  static PyObject *
  translate_into_utf8(const char* str, const char* enc) {
      PyObject *utf8;
      PyObject* buf = PyUnicode_Decode(str, strlen(str), enc, NULL);
      if (buf == NULL)
          return NULL;
      utf8 = PyUnicode_AsUTF8String(buf);
      Py_DECREF(buf);
      return utf8;
  }
  
  
  static char *
  translate_newlines(const char *s, int exec_input, struct tok_state *tok) {
      int skip_next_lf = 0;
      size_t needed_length = strlen(s) + 2, final_length;
      char *buf, *current;
      char c = '\0';
      buf = PyMem_MALLOC(needed_length);
      if (buf == NULL) {
          tok->done = E_NOMEM;
          return NULL;
      }
      for (current = buf; *s; s++, current++) {
          c = *s;
          if (skip_next_lf) {
              skip_next_lf = 0;
              if (c == '\n') {
                  c = *++s;
                  if (!c)
                      break;
              }
          }
          if (c == '\r') {
              skip_next_lf = 1;
              c = '\n';
          }
          *current = c;
      }
      /* If this is exec input, add a newline to the end of the string if
         there isn't one already. */
      if (exec_input && c != '\n') {
          *current = '\n';
          current++;
      }
      *current = '\0';
      final_length = current - buf + 1;
      if (final_length < needed_length && final_length)
          /* should never fail */
          buf = PyMem_REALLOC(buf, final_length);
      return buf;
  }
  
  /* Decode a byte string STR for use as the buffer of TOK.
     Look for encoding declarations inside STR, and record them
     inside TOK.  */
  
  static const char *
  decode_str(const char *input, int single, struct tok_state *tok)
  {
      PyObject* utf8 = NULL;
      const char *str;
      const char *s;
      const char *newl[2] = {NULL, NULL};
      int lineno = 0;
      tok->input = str = translate_newlines(input, single, tok);
      if (str == NULL)
          return NULL;
      tok->enc = NULL;
      tok->str = str;
      if (!check_bom(buf_getc, buf_ungetc, buf_setreadl, tok))
          return error_ret(tok);
      str = tok->str;             /* string after BOM if any */
      assert(str);
      if (tok->enc != NULL) {
          utf8 = translate_into_utf8(str, tok->enc);
          if (utf8 == NULL)
              return error_ret(tok);
          str = PyBytes_AsString(utf8);
      }
      for (s = str;; s++) {
          if (*s == '\0') break;
          else if (*s == '\n') {
              assert(lineno < 2);
              newl[lineno] = s;
              lineno++;
              if (lineno == 2) break;
          }
      }
      tok->enc = NULL;
      /* need to check line 1 and 2 separately since check_coding_spec
         assumes a single line as input */
      if (newl[0]) {
          if (!check_coding_spec(str, newl[0] - str, tok, buf_setreadl))
              return error_ret(tok);
          if (tok->enc == NULL && !tok->read_coding_spec && newl[1]) {
              if (!check_coding_spec(newl[0]+1, newl[1] - newl[0],
                                     tok, buf_setreadl))
                  return error_ret(tok);
          }
      }
      if (tok->enc != NULL) {
          assert(utf8 == NULL);
          utf8 = translate_into_utf8(str, tok->enc);
          if (utf8 == NULL)
              return error_ret(tok);
          str = PyBytes_AS_STRING(utf8);
      }
      assert(tok->decoding_buffer == NULL);
      tok->decoding_buffer = utf8; /* CAUTION */
      return str;
  }
  
  /* Set up tokenizer for string */
  
  struct tok_state *
  PyTokenizer_FromString(const char *str, int exec_input)
  {
      struct tok_state *tok = tok_new();
      if (tok == NULL)
          return NULL;
      str = decode_str(str, exec_input, tok);
      if (str == NULL) {
          PyTokenizer_Free(tok);
          return NULL;
      }
  
      /* XXX: constify members. */
      tok->buf = tok->cur = tok->end = tok->inp = (char*)str;
      return tok;
  }
  
  struct tok_state *
  PyTokenizer_FromUTF8(const char *str, int exec_input)
  {
      struct tok_state *tok = tok_new();
      if (tok == NULL)
          return NULL;
      tok->input = str = translate_newlines(str, exec_input, tok);
      if (str == NULL) {
          PyTokenizer_Free(tok);
          return NULL;
      }
      tok->decoding_state = STATE_RAW;
      tok->read_coding_spec = 1;
      tok->enc = NULL;
      tok->str = str;
      tok->encoding = (char *)PyMem_MALLOC(6);
      if (!tok->encoding) {
          PyTokenizer_Free(tok);
          return NULL;
      }
      strcpy(tok->encoding, "utf-8");
  
      /* XXX: constify members. */
      tok->buf = tok->cur = tok->end = tok->inp = (char*)str;
      return tok;
  }
  
  /* Set up tokenizer for file */
  
  struct tok_state *
  PyTokenizer_FromFile(FILE *fp, const char* enc,
                       const char *ps1, const char *ps2)
  {
      struct tok_state *tok = tok_new();
      if (tok == NULL)
          return NULL;
      if ((tok->buf = (char *)PyMem_MALLOC(BUFSIZ)) == NULL) {
          PyTokenizer_Free(tok);
          return NULL;
      }
      tok->cur = tok->inp = tok->buf;
      tok->end = tok->buf + BUFSIZ;
      tok->fp = fp;
      tok->prompt = ps1;
      tok->nextprompt = ps2;
      if (enc != NULL) {
          /* Must copy encoding declaration since it
             gets copied into the parse tree. */
          tok->encoding = PyMem_MALLOC(strlen(enc)+1);
          if (!tok->encoding) {
              PyTokenizer_Free(tok);
              return NULL;
          }
          strcpy(tok->encoding, enc);
          tok->decoding_state = STATE_NORMAL;
      }
      return tok;
  }
  
  
  /* Free a tok_state structure */
  
  void
  PyTokenizer_Free(struct tok_state *tok)
  {
      if (tok->encoding != NULL)
          PyMem_FREE(tok->encoding);
      Py_XDECREF(tok->decoding_readline);
      Py_XDECREF(tok->decoding_buffer);
      Py_XDECREF(tok->filename);
      if (tok->fp != NULL && tok->buf != NULL)
          PyMem_FREE(tok->buf);
      if (tok->input)
          PyMem_FREE((char *)tok->input);
      PyMem_FREE(tok);
  }
  
  /* Get next char, updating state; error code goes into tok->done */
  
  static int
  tok_nextc(struct tok_state *tok)
  {
      for (;;) {
          if (tok->cur != tok->inp) {
              return Py_CHARMASK(*tok->cur++); /* Fast path */
          }
          if (tok->done != E_OK)
              return EOF;
          if (tok->fp == NULL) {
              char *end = strchr(tok->inp, '\n');
              if (end != NULL)
                  end++;
              else {
                  end = strchr(tok->inp, '\0');
                  if (end == tok->inp) {
                      tok->done = E_EOF;
                      return EOF;
                  }
              }
              if (tok->start == NULL)
                  tok->buf = tok->cur;
              tok->line_start = tok->cur;
              tok->lineno++;
              tok->inp = end;
              return Py_CHARMASK(*tok->cur++);
          }
          if (tok->prompt != NULL) {
              char *newtok = PyOS_Readline(stdin, stdout, tok->prompt);
              if (newtok != NULL) {
                  char *translated = translate_newlines(newtok, 0, tok);
                  PyMem_FREE(newtok);
                  if (translated == NULL)
                      return EOF;
                  newtok = translated;
              }
              if (tok->encoding && newtok && *newtok) {
                  /* Recode to UTF-8 */
                  Py_ssize_t buflen;
                  const char* buf;
                  PyObject *u = translate_into_utf8(newtok, tok->encoding);
                  PyMem_FREE(newtok);
                  if (!u) {
                      tok->done = E_DECODE;
                      return EOF;
                  }
                  buflen = PyBytes_GET_SIZE(u);
                  buf = PyBytes_AS_STRING(u);
                  newtok = PyMem_MALLOC(buflen+1);
                  if (newtok == NULL) {
                      Py_DECREF(u);
                      tok->done = E_NOMEM;
                      return EOF;
                  }
                  strcpy(newtok, buf);
                  Py_DECREF(u);
              }
              if (tok->nextprompt != NULL)
                  tok->prompt = tok->nextprompt;
              if (newtok == NULL)
                  tok->done = E_INTR;
              else if (*newtok == '\0') {
                  PyMem_FREE(newtok);
                  tok->done = E_EOF;
              }
              else if (tok->start != NULL) {
                  size_t start = tok->start - tok->buf;
                  size_t oldlen = tok->cur - tok->buf;
                  size_t newlen = oldlen + strlen(newtok);
                  char *buf = tok->buf;
                  buf = (char *)PyMem_REALLOC(buf, newlen+1);
                  tok->lineno++;
                  if (buf == NULL) {
                      PyMem_FREE(tok->buf);
                      tok->buf = NULL;
                      PyMem_FREE(newtok);
                      tok->done = E_NOMEM;
                      return EOF;
                  }
                  tok->buf = buf;
                  tok->cur = tok->buf + oldlen;
                  tok->line_start = tok->cur;
                  strcpy(tok->buf + oldlen, newtok);
                  PyMem_FREE(newtok);
                  tok->inp = tok->buf + newlen;
                  tok->end = tok->inp + 1;
                  tok->start = tok->buf + start;
              }
              else {
                  tok->lineno++;
                  if (tok->buf != NULL)
                      PyMem_FREE(tok->buf);
                  tok->buf = newtok;
                  tok->cur = tok->buf;
                  tok->line_start = tok->buf;
                  tok->inp = strchr(tok->buf, '\0');
                  tok->end = tok->inp + 1;
              }
          }
          else {
              int done = 0;
              Py_ssize_t cur = 0;
              char *pt;
              if (tok->start == NULL) {
                  if (tok->buf == NULL) {
                      tok->buf = (char *)
                          PyMem_MALLOC(BUFSIZ);
                      if (tok->buf == NULL) {
                          tok->done = E_NOMEM;
                          return EOF;
                      }
                      tok->end = tok->buf + BUFSIZ;
                  }
                  if (decoding_fgets(tok->buf, (int)(tok->end - tok->buf),
                            tok) == NULL) {
                      if (!tok->decoding_erred)
                          tok->done = E_EOF;
                      done = 1;
                  }
                  else {
                      tok->done = E_OK;
                      tok->inp = strchr(tok->buf, '\0');
                      done = tok->inp == tok->buf || tok->inp[-1] == '\n';
                  }
              }
              else {
                  cur = tok->cur - tok->buf;
                  if (decoding_feof(tok)) {
                      tok->done = E_EOF;
                      done = 1;
                  }
                  else
                      tok->done = E_OK;
              }
              tok->lineno++;
              /* Read until '\n' or EOF */
              while (!done) {
                  Py_ssize_t curstart = tok->start == NULL ? -1 :
                            tok->start - tok->buf;
                  Py_ssize_t curvalid = tok->inp - tok->buf;
                  Py_ssize_t newsize = curvalid + BUFSIZ;
                  char *newbuf = tok->buf;
                  newbuf = (char *)PyMem_REALLOC(newbuf,
                                                 newsize);
                  if (newbuf == NULL) {
                      tok->done = E_NOMEM;
                      tok->cur = tok->inp;
                      return EOF;
                  }
                  tok->buf = newbuf;
                  tok->cur = tok->buf + cur;
                  tok->line_start = tok->cur;
                  tok->inp = tok->buf + curvalid;
                  tok->end = tok->buf + newsize;
                  tok->start = curstart < 0 ? NULL :
                           tok->buf + curstart;
                  if (decoding_fgets(tok->inp,
                                 (int)(tok->end - tok->inp),
                                 tok) == NULL) {
                      /* Break out early on decoding
                         errors, as tok->buf will be NULL
                       */
                      if (tok->decoding_erred)
                          return EOF;
                      /* Last line does not end in \n,
                         fake one */
                      strcpy(tok->inp, "\n");
                  }
                  tok->inp = strchr(tok->inp, '\0');
                  done = tok->inp[-1] == '\n';
              }
              if (tok->buf != NULL) {
                  tok->cur = tok->buf + cur;
                  tok->line_start = tok->cur;
                  /* replace "\r\n" with "\n" */
                  /* For Mac leave the \r, giving a syntax error */
                  pt = tok->inp - 2;
                  if (pt >= tok->buf && *pt == '\r') {
                      *pt++ = '\n';
                      *pt = '\0';
                      tok->inp = pt;
                  }
              }
          }
          if (tok->done != E_OK) {
              if (tok->prompt != NULL)
                  PySys_WriteStderr("\n");
              tok->cur = tok->inp;
              return EOF;
          }
      }
      /*NOTREACHED*/
  }
  
  
  /* Back-up one character */
  
  static void
  tok_backup(struct tok_state *tok, int c)
  {
      if (c != EOF) {
          if (--tok->cur < tok->buf)
              Py_FatalError("tok_backup: beginning of buffer");
          if (*tok->cur != c)
              *tok->cur = c;
      }
  }
  
  
  static int
  syntaxerror(struct tok_state *tok, const char *format, ...)
  {
      va_list vargs;
  #ifdef HAVE_STDARG_PROTOTYPES
      va_start(vargs, format);
  #else
      va_start(vargs);
  #endif
      PyErr_FormatV(PyExc_SyntaxError, format, vargs);
      va_end(vargs);
      PyErr_SyntaxLocationObject(tok->filename,
                                 tok->lineno,
                                 (int)(tok->cur - tok->line_start));
      tok->done = E_ERROR;
      return ERRORTOKEN;
  }
  
  static int
  indenterror(struct tok_state *tok)
  {
      tok->done = E_TABSPACE;
      tok->cur = tok->inp;
      return ERRORTOKEN;
  }
  
  /* Verify that the identifier follows PEP 3131.
     All identifier strings are guaranteed to be "ready" unicode objects.
   */
  static int
  verify_identifier(struct tok_state *tok)
  {
      PyObject *s;
      int result;
      if (tok->decoding_erred)
          return 0;
      s = PyUnicode_DecodeUTF8(tok->start, tok->cur - tok->start, NULL);
      if (s == NULL) {
          if (PyErr_ExceptionMatches(PyExc_UnicodeDecodeError)) {
              PyErr_Clear();
              tok->done = E_IDENTIFIER;
          } else {
              tok->done = E_ERROR;
          }
          return 0;
      }
      result = PyUnicode_IsIdentifier(s);
      Py_DECREF(s);
      if (result == 0)
          tok->done = E_IDENTIFIER;
      return result;
  }
  
  static int
  tok_decimal_tail(struct tok_state *tok)
  {
      int c;
  
      while (1) {
          do {
              c = tok_nextc(tok);
          } while (isdigit(c));
          if (c != '_') {
              break;
          }
          c = tok_nextc(tok);
          if (!isdigit(c)) {
              tok_backup(tok, c);
              syntaxerror(tok, "invalid decimal literal");
              return 0;
          }
      }
      return c;
  }
  
  /* Get next token, after space stripping etc. */
  
  static int
  tok_get(struct tok_state *tok, char **p_start, char **p_end)
  {
      int c;
      int blankline, nonascii;
  
      *p_start = *p_end = NULL;
    nextline:
      tok->start = NULL;
      blankline = 0;
  
      /* Get indentation level */
      if (tok->atbol) {
          int col = 0;
          int altcol = 0;
          tok->atbol = 0;
          for (;;) {
              c = tok_nextc(tok);
              if (c == ' ') {
                  col++, altcol++;
              }
              else if (c == '\t') {
                  col = (col / tok->tabsize + 1) * tok->tabsize;
                  altcol = (altcol / ALTTABSIZE + 1) * ALTTABSIZE;
              }
              else if (c == '\014')  {/* Control-L (formfeed) */
                  col = altcol = 0; /* For Emacs users */
              }
              else {
                  break;
              }
          }
          tok_backup(tok, c);
          if (c == '#' || c == '\n') {
              /* Lines with only whitespace and/or comments
                 shouldn't affect the indentation and are
                 not passed to the parser as NEWLINE tokens,
                 except *totally* empty lines in interactive
                 mode, which signal the end of a command group. */
              if (col == 0 && c == '\n' && tok->prompt != NULL) {
                  blankline = 0; /* Let it through */
              }
              else {
                  blankline = 1; /* Ignore completely */
              }
              /* We can't jump back right here since we still
                 may need to skip to the end of a comment */
          }
          if (!blankline && tok->level == 0) {
              if (col == tok->indstack[tok->indent]) {
                  /* No change */
                  if (altcol != tok->altindstack[tok->indent]) {
                      return indenterror(tok);
                  }
              }
              else if (col > tok->indstack[tok->indent]) {
                  /* Indent -- always one */
                  if (tok->indent+1 >= MAXINDENT) {
                      tok->done = E_TOODEEP;
                      tok->cur = tok->inp;
                      return ERRORTOKEN;
                  }
                  if (altcol <= tok->altindstack[tok->indent]) {
                      return indenterror(tok);
                  }
                  tok->pendin++;
                  tok->indstack[++tok->indent] = col;
                  tok->altindstack[tok->indent] = altcol;
              }
              else /* col < tok->indstack[tok->indent] */ {
                  /* Dedent -- any number, must be consistent */
                  while (tok->indent > 0 &&
                      col < tok->indstack[tok->indent]) {
                      tok->pendin--;
                      tok->indent--;
                  }
                  if (col != tok->indstack[tok->indent]) {
                      tok->done = E_DEDENT;
                      tok->cur = tok->inp;
                      return ERRORTOKEN;
                  }
                  if (altcol != tok->altindstack[tok->indent]) {
                      return indenterror(tok);
                  }
              }
          }
      }
  
      tok->start = tok->cur;
  
      /* Return pending indents/dedents */
      if (tok->pendin != 0) {
          if (tok->pendin < 0) {
              tok->pendin++;
              return DEDENT;
          }
          else {
              tok->pendin--;
              return INDENT;
          }
      }
  
   again:
      tok->start = NULL;
      /* Skip spaces */
      do {
          c = tok_nextc(tok);
      } while (c == ' ' || c == '\t' || c == '\014');
  
      /* Set start of current token */
      tok->start = tok->cur - 1;
  
      /* Skip comment, unless it's a type comment */
      if (c == '#') {
          const char *prefix, *p, *type_start;
  
          while (c != EOF && c != '\n') {
              c = tok_nextc(tok);
          }
  
          if (tok->type_comments) {
              p = tok->start;
              prefix = type_comment_prefix;
              while (*prefix && p < tok->cur) {
                  if (*prefix == ' ') {
                      while (*p == ' ' || *p == '\t') {
                          p++;
                      }
                  } else if (*prefix == *p) {
                      p++;
                  } else {
                      break;
                  }
  
                  prefix++;
              }
  
              /* This is a type comment if we matched all of type_comment_prefix. */
              if (!*prefix) {
                  int is_type_ignore = 1;
                  tok_backup(tok, c);  /* don't eat the newline or EOF */
  
                  type_start = p;
  
                  is_type_ignore = tok->cur >= p + 6 && memcmp(p, "ignore", 6) == 0;
                  p += 6;
                  while (is_type_ignore && p < tok->cur) {
                      if (*p == '#')
                          break;
                      is_type_ignore = is_type_ignore && (*p == ' ' || *p == '\t');
                      p++;
                  }
  
                  if (is_type_ignore) {
                      /* If this type ignore is the only thing on the line, consume the newline also. */
                      if (blankline) {
                          tok_nextc(tok);
                          tok->atbol = 1;
                      }
                      return TYPE_IGNORE;
                  } else {
                      *p_start = (char *) type_start;  /* after type_comment_prefix */
                      *p_end = tok->cur;
                      return TYPE_COMMENT;
                  }
              }
          }
      }
  
      /* Check for EOF and errors now */
      if (c == EOF) {
          return tok->done == E_EOF ? ENDMARKER : ERRORTOKEN;
      }
  
      /* Identifier (most frequent token!) */
      nonascii = 0;
      if (is_potential_identifier_start(c)) {
          /* Process the various legal combinations of b"", r"", u"", and f"". */
          int saw_b = 0, saw_r = 0, saw_u = 0, saw_f = 0;
          while (1) {
              if (!(saw_b || saw_u || saw_f) && (c == 'b' || c == 'B'))
                  saw_b = 1;
              /* Since this is a backwards compatibility support literal we don't
                 want to support it in arbitrary order like byte literals. */
              else if (!(saw_b || saw_u || saw_r || saw_f)
                       && (c == 'u'|| c == 'U')) {
                  saw_u = 1;
              }
              /* ur"" and ru"" are not supported */
              else if (!(saw_r || saw_u) && (c == 'r' || c == 'R')) {
                  saw_r = 1;
              }
              else if (!(saw_f || saw_b || saw_u) && (c == 'f' || c == 'F')) {
                  saw_f = 1;
              }
              else {
                  break;
              }
              c = tok_nextc(tok);
              if (c == '"' || c == '\'') {
                  goto letter_quote;
              }
          }
          while (is_potential_identifier_char(c)) {
              if (c >= 128) {
                  nonascii = 1;
              }
              c = tok_nextc(tok);
          }
          tok_backup(tok, c);
          if (nonascii && !verify_identifier(tok)) {
              return ERRORTOKEN;
          }
          *p_start = tok->start;
          *p_end = tok->cur;
  
          return NAME;
      }
  
      /* Newline */
      if (c == '\n') {
          tok->atbol = 1;
          if (blankline || tok->level > 0) {
              goto nextline;
          }
          *p_start = tok->start;
          *p_end = tok->cur - 1; /* Leave '\n' out of the string */
          tok->cont_line = 0;
          return NEWLINE;
      }
  
      /* Period or number starting with period? */
      if (c == '.') {
          c = tok_nextc(tok);
          if (isdigit(c)) {
              goto fraction;
          } else if (c == '.') {
              c = tok_nextc(tok);
              if (c == '.') {
                  *p_start = tok->start;
                  *p_end = tok->cur;
                  return ELLIPSIS;
              }
              else {
                  tok_backup(tok, c);
              }
              tok_backup(tok, '.');
          }
          else {
              tok_backup(tok, c);
          }
          *p_start = tok->start;
          *p_end = tok->cur;
          return DOT;
      }
  
      /* Number */
      if (isdigit(c)) {
          if (c == '0') {
              /* Hex, octal or binary -- maybe. */
              c = tok_nextc(tok);
              if (c == 'x' || c == 'X') {
                  /* Hex */
                  c = tok_nextc(tok);
                  do {
                      if (c == '_') {
                          c = tok_nextc(tok);
                      }
                      if (!isxdigit(c)) {
                          tok_backup(tok, c);
                          return syntaxerror(tok, "invalid hexadecimal literal");
                      }
                      do {
                          c = tok_nextc(tok);
                      } while (isxdigit(c));
                  } while (c == '_');
              }
              else if (c == 'o' || c == 'O') {
                  /* Octal */
                  c = tok_nextc(tok);
                  do {
                      if (c == '_') {
                          c = tok_nextc(tok);
                      }
                      if (c < '0' || c >= '8') {
                          tok_backup(tok, c);
                          if (isdigit(c)) {
                              return syntaxerror(tok,
                                      "invalid digit '%c' in octal literal", c);
                          }
                          else {
                              return syntaxerror(tok, "invalid octal literal");
                          }
                      }
                      do {
                          c = tok_nextc(tok);
                      } while ('0' <= c && c < '8');
                  } while (c == '_');
                  if (isdigit(c)) {
                      return syntaxerror(tok,
                              "invalid digit '%c' in octal literal", c);
                  }
              }
              else if (c == 'b' || c == 'B') {
                  /* Binary */
                  c = tok_nextc(tok);
                  do {
                      if (c == '_') {
                          c = tok_nextc(tok);
                      }
                      if (c != '0' && c != '1') {
                          tok_backup(tok, c);
                          if (isdigit(c)) {
                              return syntaxerror(tok,
                                      "invalid digit '%c' in binary literal", c);
                          }
                          else {
                              return syntaxerror(tok, "invalid binary literal");
                          }
                      }
                      do {
                          c = tok_nextc(tok);
                      } while (c == '0' || c == '1');
                  } while (c == '_');
                  if (isdigit(c)) {
                      return syntaxerror(tok,
                              "invalid digit '%c' in binary literal", c);
                  }
              }
              else {
                  int nonzero = 0;
                  /* maybe old-style octal; c is first char of it */
                  /* in any case, allow '0' as a literal */
                  while (1) {
                      if (c == '_') {
                          c = tok_nextc(tok);
                          if (!isdigit(c)) {
                              tok_backup(tok, c);
                              return syntaxerror(tok, "invalid decimal literal");
                          }
                      }
                      if (c != '0') {
                          break;
                      }
                      c = tok_nextc(tok);
                  }
                  if (isdigit(c)) {
                      nonzero = 1;
                      c = tok_decimal_tail(tok);
                      if (c == 0) {
                          return ERRORTOKEN;
                      }
                  }
                  if (c == '.') {
                      c = tok_nextc(tok);
                      goto fraction;
                  }
                  else if (c == 'e' || c == 'E') {
                      goto exponent;
                  }
                  else if (c == 'j' || c == 'J') {
                      goto imaginary;
                  }
                  else if (nonzero) {
                      /* Old-style octal: now disallowed. */
                      tok_backup(tok, c);
                      return syntaxerror(tok,
                                         "leading zeros in decimal integer "
                                         "literals are not permitted; "
                                         "use an 0o prefix for octal integers");
                  }
              }
          }
          else {
              /* Decimal */
              c = tok_decimal_tail(tok);
              if (c == 0) {
                  return ERRORTOKEN;
              }
              {
                  /* Accept floating point numbers. */
                  if (c == '.') {
                      c = tok_nextc(tok);
          fraction:
                      /* Fraction */
                      if (isdigit(c)) {
                          c = tok_decimal_tail(tok);
                          if (c == 0) {
                              return ERRORTOKEN;
                          }
                      }
                  }
                  if (c == 'e' || c == 'E') {
                      int e;
                    exponent:
                      e = c;
                      /* Exponent part */
                      c = tok_nextc(tok);
                      if (c == '+' || c == '-') {
                          c = tok_nextc(tok);
                          if (!isdigit(c)) {
                              tok_backup(tok, c);
                              return syntaxerror(tok, "invalid decimal literal");
                          }
                      } else if (!isdigit(c)) {
                          tok_backup(tok, c);
                          tok_backup(tok, e);
                          *p_start = tok->start;
                          *p_end = tok->cur;
                          return NUMBER;
                      }
                      c = tok_decimal_tail(tok);
                      if (c == 0) {
                          return ERRORTOKEN;
                      }
                  }
                  if (c == 'j' || c == 'J') {
                      /* Imaginary part */
          imaginary:
                      c = tok_nextc(tok);
                  }
              }
          }
          tok_backup(tok, c);
          *p_start = tok->start;
          *p_end = tok->cur;
          return NUMBER;
      }
  
    letter_quote:
      /* String */
      if (c == '\'' || c == '"') {
          int quote = c;
          int quote_size = 1;             /* 1 or 3 */
          int end_quote_size = 0;
  
          /* Nodes of type STRING, especially multi line strings
             must be handled differently in order to get both
             the starting line number and the column offset right.
             (cf. issue 16806) */
          tok->first_lineno = tok->lineno;
          tok->multi_line_start = tok->line_start;
  
          /* Find the quote size and start of string */
          c = tok_nextc(tok);
          if (c == quote) {
              c = tok_nextc(tok);
              if (c == quote) {
                  quote_size = 3;
              }
              else {
                  end_quote_size = 1;     /* empty string found */
              }
          }
          if (c != quote) {
              tok_backup(tok, c);
          }
  
          /* Get rest of string */
          while (end_quote_size != quote_size) {
              c = tok_nextc(tok);
              if (c == EOF) {
                  if (quote_size == 3) {
                      tok->done = E_EOFS;
                  }
                  else {
                      tok->done = E_EOLS;
                  }
                  tok->cur = tok->inp;
                  return ERRORTOKEN;
              }
              if (quote_size == 1 && c == '\n') {
                  tok->done = E_EOLS;
                  tok->cur = tok->inp;
                  return ERRORTOKEN;
              }
              if (c == quote) {
                  end_quote_size += 1;
              }
              else {
                  end_quote_size = 0;
                  if (c == '\\') {
                      tok_nextc(tok);  /* skip escaped char */
                  }
              }
          }
  
          *p_start = tok->start;
          *p_end = tok->cur;
          return STRING;
      }
  
      /* Line continuation */
      if (c == '\\') {
          c = tok_nextc(tok);
          if (c != '\n') {
              tok->done = E_LINECONT;
              tok->cur = tok->inp;
              return ERRORTOKEN;
          }
          tok->cont_line = 1;
          goto again; /* Read next line */
      }
  
      /* Check for two-character token */
      {
          int c2 = tok_nextc(tok);
          int token = PyToken_TwoChars(c, c2);
          if (token != OP) {
              int c3 = tok_nextc(tok);
              int token3 = PyToken_ThreeChars(c, c2, c3);
              if (token3 != OP) {
                  token = token3;
              }
              else {
                  tok_backup(tok, c3);
              }
              *p_start = tok->start;
              *p_end = tok->cur;
              return token;
          }
          tok_backup(tok, c2);
      }
  
      /* Keep track of parentheses nesting level */
      switch (c) {
      case '(':
      case '[':
      case '{':
          if (tok->level >= MAXLEVEL) {
              return syntaxerror(tok, "too many nested parentheses");
          }
          tok->parenstack[tok->level] = c;
          tok->parenlinenostack[tok->level] = tok->lineno;
          tok->level++;
          break;
      case ')':
      case ']':
      case '}':
          if (!tok->level) {
              return syntaxerror(tok, "unmatched '%c'", c);
          }
          tok->level--;
          int opening = tok->parenstack[tok->level];
          if (!((opening == '(' && c == ')') ||
                (opening == '[' && c == ']') ||
                (opening == '{' && c == '}')))
          {
              if (tok->parenlinenostack[tok->level] != tok->lineno) {
                  return syntaxerror(tok,
                          "closing parenthesis '%c' does not match "
                          "opening parenthesis '%c' on line %d",
                          c, opening, tok->parenlinenostack[tok->level]);
              }
              else {
                  return syntaxerror(tok,
                          "closing parenthesis '%c' does not match "
                          "opening parenthesis '%c'",
                          c, opening);
              }
          }
          break;
      }
  
      /* Punctuation character */
      *p_start = tok->start;
      *p_end = tok->cur;
      return PyToken_OneChar(c);
  }
  
  int
  PyTokenizer_Get(struct tok_state *tok, char **p_start, char **p_end)
  {
      int result = tok_get(tok, p_start, p_end);
      if (tok->decoding_erred) {
          result = ERRORTOKEN;
          tok->done = E_DECODE;
      }
      return result;
  }
  
  /* Get the encoding of a Python file. Check for the coding cookie and check if
     the file starts with a BOM.
  
     PyTokenizer_FindEncodingFilename() returns NULL when it can't find the
     encoding in the first or second line of the file (in which case the encoding
     should be assumed to be UTF-8).
  
     The char* returned is malloc'ed via PyMem_MALLOC() and thus must be freed
     by the caller. */
  
  char *
  PyTokenizer_FindEncodingFilename(int fd, PyObject *filename)
  {
      struct tok_state *tok;
      FILE *fp;
      char *p_start =NULL , *p_end =NULL , *encoding = NULL;
  
      fd = _Py_dup(fd);
      if (fd < 0) {
          return NULL;
      }
  
      fp = fdopen(fd, "r");
      if (fp == NULL) {
          return NULL;
      }
      tok = PyTokenizer_FromFile(fp, NULL, NULL, NULL);
      if (tok == NULL) {
          fclose(fp);
          return NULL;
      }
      if (filename != NULL) {
          Py_INCREF(filename);
          tok->filename = filename;
      }
      else {
          tok->filename = PyUnicode_FromString("<string>");
          if (tok->filename == NULL) {
              fclose(fp);
              PyTokenizer_Free(tok);
              return encoding;
          }
      }
      while (tok->lineno < 2 && tok->done == E_OK) {
          PyTokenizer_Get(tok, &p_start, &p_end);
      }
      fclose(fp);
      if (tok->encoding) {
          encoding = (char *)PyMem_MALLOC(strlen(tok->encoding) + 1);
          if (encoding)
          strcpy(encoding, tok->encoding);
      }
      PyTokenizer_Free(tok);
      return encoding;
  }
  
  char *
  PyTokenizer_FindEncoding(int fd)
  {
      return PyTokenizer_FindEncodingFilename(fd, NULL);
  }
  
  #ifdef Py_DEBUG
  
  void
  tok_dump(int type, char *start, char *end)
  {
      printf("%s", _PyParser_TokenNames[type]);
      if (type == NAME || type == NUMBER || type == STRING || type == OP)
          printf("(%.*s)", (int)(end - start), start);
  }
  
  #endif
  