~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Copyright (C) 2008 Sun Microsystems, Inc.

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; version 2 of the License.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

#include "config.h"

#include <drizzled/util/convert.h>

#include "drizzled/internal/m_string.h"

#include <drizzled/plugin/function.h>

#include <drizzled/function/str/strfunc.h>

using namespace drizzled;

class HexFunction :public Item_str_func

{

  String tmp_value;

public:

  HexFunction() :Item_str_func() {}

  const char *func_name() const { return "hex"; }

  String *val_str(String *);

  void fix_length_and_dec()

  {

    collation.set(default_charset());

    decimals=0;

    max_length=args[0]->max_length*2*collation.collation->mbmaxlen;

  }

  bool check_argument_count(int n) { return n == 1; }

};

class UnHexFunction :public Item_str_func

{

  String tmp_value;

public:

  UnHexFunction() :Item_str_func()

  {

    /* there can be bad hex strings */

    maybe_null= 1;

  }

  const char *func_name() const { return "unhex"; }

  String *val_str(String *);

  void fix_length_and_dec()

  {

    collation.set(&my_charset_bin);

    decimals=0;

    max_length=(1+args[0]->max_length)/2;

  }

  bool check_argument_count(int n) { return n == 1; }

};

/**

  convert a hex digit into number.

*/

static int hexchar_to_int(char c)

{

  if (c <= '9' && c >= '0')

    return c-'0';

  c|=32;

  if (c <= 'f' && c >= 'a')

    return c-'a'+10;

  return -1;

}

String *HexFunction::val_str(String *str)

{

  String *res;

  assert(fixed == 1);

  if (args[0]->result_type() != STRING_RESULT)

  {

    uint64_t dec;

    char ans[65],*ptr;

    /* Return hex of unsigned int64_t value */

    if (args[0]->result_type() == REAL_RESULT ||

        args[0]->result_type() == DECIMAL_RESULT)

    {

      double val= args[0]->val_real();

      if ((val <= (double) INT64_MIN) ||

          (val >= (double) (uint64_t) UINT64_MAX))

        dec=  ~(int64_t) 0;

      else

        dec= (uint64_t) (val + (val > 0 ? 0.5 : -0.5));

    }

    else

      dec= (uint64_t) args[0]->val_int();

    if ((null_value= args[0]->null_value))

      return 0;

    ptr= internal::int64_t2str(dec,ans,16);

    if (str->copy(ans,(uint32_t) (ptr-ans),default_charset()))

      return &my_empty_string;			// End of memory

    return str;

  }

  /* Convert given string to a hex string, character by character */

  res= args[0]->val_str(str);

  if (!res || tmp_value.alloc(res->length()*2+1))

  {

    null_value=1;

    return 0;

  }

  null_value=0;

  tmp_value.length(res->length()*2);

  (void) drizzled_string_to_hex((char*) tmp_value.ptr(), res->ptr(),

                                res->length());

  return &tmp_value;

}

  /** Convert given hex string to a binary string. */

String *UnHexFunction::val_str(String *str)

{

  const char *from, *end;

  char *to;

  String *res;

  uint32_t length;

  assert(fixed == 1);

  res= args[0]->val_str(str);

  if (!res || tmp_value.alloc(length= (1+res->length())/2))

  {

    null_value=1;

    return 0;

  }

  from= res->ptr();

  null_value= 0;

  tmp_value.length(length);

  to= (char*) tmp_value.ptr();

  if (res->length() % 2)

  {

    int hex_char;

    *to++= hex_char= hexchar_to_int(*from++);

    if ((null_value= (hex_char == -1)))

      return 0;

  }

  for (end=res->ptr()+res->length(); from < end ; from+=2, to++)

  {

    int hex_char;

    *to= (hex_char= hexchar_to_int(from[0])) << 4;

    if ((null_value= (hex_char == -1)))

      return 0;

    *to|= hex_char= hexchar_to_int(from[1]);

    if ((null_value= (hex_char == -1)))

      return 0;

  }

  return &tmp_value;

}

plugin::Create_function<HexFunction> *hex_function= NULL;

plugin::Create_function<UnHexFunction> *unhex_function= NULL;

static int initialize(drizzled::module::Context &context)

{

  hex_function= new plugin::Create_function<HexFunction>("hex");

  unhex_function= new plugin::Create_function<UnHexFunction>("unhex");

  context.add(hex_function);

  context.add(unhex_function);

  return 0;

}

DRIZZLE_DECLARE_PLUGIN

{

  DRIZZLE_VERSION_ID,

  "hex_functions",

  "1.0",

  "Stewart Smith",

  "Convert a string to HEX() or from UNHEX()",

  PLUGIN_LICENSE_GPL,

  initialize, /* Plugin Init */

  NULL,   /* system variables */

  NULL    /* config options */

}

DRIZZLE_DECLARE_PLUGIN_END;