Function get_56_lenc_string

phx_percona/percona/sql/sql_acl.cc:10496–10538

*/

static
char *get_56_lenc_string(char **buffer,
                         size_t *max_bytes_available,
                         size_t *string_length)
{
  static char empty_string[1]= { '\0' };
  char *begin= *buffer;

  if (*max_bytes_available == 0)
    return NULL;

  /*
    If the length encoded string has the length 0
    the total size of the string is only one byte long (the size byte)
  */
  if (*begin == 0)
  {
    *string_length= 0;
    --*max_bytes_available;
    ++*buffer;
    /*
      Return a pointer to the \0 character so the return value will be
      an empty string.
    */
    return empty_string;
  }

  *string_length= (size_t)net_field_length_ll((uchar **)buffer);

  DBUG_EXECUTE_IF("sha256_password_scramble_too_long",
                  *string_length= SIZE_T_MAX;
  );

  size_t len_len= (size_t)(*buffer - begin);
  
  if (*string_length > *max_bytes_available - len_len)
    return NULL;

  *max_bytes_available -= *string_length;
  *max_bytes_available -= len_len;
  *buffer += *string_length;
  return (char *)(begin + len_len);
}


/**