~drizzle-trunk/drizzle/development

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

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

 *

 *  Copyright (C) 2008 MySQL

 *

 *  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; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  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 <drizzled/server_includes.h>

#include <drizzled/field/varstring.h>

#include <drizzled/table.h>

#include <drizzled/session.h>

/****************************************************************************

  VARCHAR type

  Data in field->ptr is stored as:

    1 or 2 bytes length-prefix-header  (from Field_varstring::length_bytes)

    data

  NOTE:

  When VARCHAR is stored in a key (for handler::index_read() etc) it's always

  stored with a 2 byte prefix. (Just like blob keys).

  Normally length_bytes is calculated as (field_length < 256 : 1 ? 2)

  The exception is if there is a prefix key field that is part of a long

  VARCHAR, in which case field_length for this may be 1 but the length_bytes

  is 2.

****************************************************************************/

const uint32_t Field_varstring::MAX_SIZE= UINT16_MAX;

Field_varstring::Field_varstring(unsigned char *ptr_arg,

                                 uint32_t len_arg, uint32_t length_bytes_arg,

                                 unsigned char *null_ptr_arg,

                                 unsigned char null_bit_arg,

                                 enum utype unireg_check_arg,

                                 const char *field_name_arg,

                                 TABLE_SHARE *share,

                                 const CHARSET_INFO * const cs)

  :Field_longstr(ptr_arg, len_arg, null_ptr_arg, null_bit_arg,

                 unireg_check_arg, field_name_arg, cs),

   length_bytes(length_bytes_arg)

{

  share->varchar_fields++;

}

Field_varstring::Field_varstring(uint32_t len_arg,bool maybe_null_arg,

                                 const char *field_name_arg,

                                 TABLE_SHARE *share,

                                 const CHARSET_INFO * const cs)

  :Field_longstr((unsigned char*) 0,len_arg,

                 maybe_null_arg ? (unsigned char*) "": 0, 0,

                 NONE, field_name_arg, cs),

   length_bytes(len_arg < 256 ? 1 :2)

{

  share->varchar_fields++;

}

/**

   Save the field metadata for varstring fields.

   Saves the field length in the first byte. Note: may consume

   2 bytes. Caller must ensure second byte is contiguous with

   first byte (e.g. array index 0,1).

   @param   metadata_ptr   First byte of field metadata

   @returns number of bytes written to metadata_ptr

*/

int Field_varstring::do_save_field_metadata(unsigned char *metadata_ptr)

{

  char *ptr= (char *)metadata_ptr;

  assert(field_length <= 65535);

  int2store(ptr, field_length);

  return 2;

}

int Field_varstring::store(const char *from,uint32_t length, const CHARSET_INFO * const cs)

{

  uint32_t copy_length;

  const char *well_formed_error_pos;

  const char *cannot_convert_error_pos;

  const char *from_end_pos;

  copy_length= well_formed_copy_nchars(field_charset,

                                       (char*) ptr + length_bytes,

                                       field_length,

                                       cs, from, length,

                                       field_length / field_charset->mbmaxlen,

                                       &well_formed_error_pos,

                                       &cannot_convert_error_pos,

                                       &from_end_pos);

  if (length_bytes == 1)

    *ptr= (unsigned char) copy_length;

  else

    int2store(ptr, copy_length);

  if (check_string_copy_error(this, well_formed_error_pos,

                              cannot_convert_error_pos, from + length, cs))

    return 2;

  return report_if_important_data(from_end_pos, from + length);

}

int Field_varstring::store(int64_t nr, bool unsigned_val)

{

  char buff[64];

  uint32_t  length;

  length= (uint) (field_charset->cset->int64_t10_to_str)(field_charset,

                                                          buff,

                                                          sizeof(buff),

                                                          (unsigned_val ? 10:

                                                           -10),

                                                           nr);

  return Field_varstring::store(buff, length, field_charset);

}

double Field_varstring::val_real(void)

{

  int not_used;

  char *end_not_used;

  uint32_t length= length_bytes == 1 ? (uint) *ptr : uint2korr(ptr);

  return my_strntod(field_charset, (char*) ptr+length_bytes, length,

                    &end_not_used, &not_used);

}

int64_t Field_varstring::val_int(void)

{

  int not_used;

  char *end_not_used;

  uint32_t length= length_bytes == 1 ? (uint) *ptr : uint2korr(ptr);

  return my_strntoll(field_charset, (char*) ptr+length_bytes, length, 10,

                     &end_not_used, &not_used);

}

String *Field_varstring::val_str(String *val_buffer __attribute__((unused)),

				 String *val_ptr)

{

  uint32_t length=  length_bytes == 1 ? (uint) *ptr : uint2korr(ptr);

  val_ptr->set((const char*) ptr+length_bytes, length, field_charset);

  return val_ptr;

}

my_decimal *Field_varstring::val_decimal(my_decimal *decimal_value)

{

  uint32_t length= length_bytes == 1 ? (uint) *ptr : uint2korr(ptr);

  str2my_decimal(E_DEC_FATAL_ERROR, (char*) ptr+length_bytes, length,

                 charset(), decimal_value);

  return decimal_value;

}

int Field_varstring::cmp_max(const unsigned char *a_ptr, const unsigned char *b_ptr,

                             uint32_t max_len)

{

  uint32_t a_length, b_length;

  int diff;

  if (length_bytes == 1)

  {

    a_length= (uint) *a_ptr;

    b_length= (uint) *b_ptr;

  }

  else

  {

    a_length= uint2korr(a_ptr);

    b_length= uint2korr(b_ptr);

  }

  set_if_smaller(a_length, max_len);

  set_if_smaller(b_length, max_len);

  diff= field_charset->coll->strnncollsp(field_charset,

                                         a_ptr+

                                         length_bytes,

                                         a_length,

                                         b_ptr+

                                         length_bytes,

                                         b_length,0);

  return diff;

}

/**

  @note

    varstring and blob keys are ALWAYS stored with a 2 byte length prefix

*/

int Field_varstring::key_cmp(const unsigned char *key_ptr, uint32_t max_key_length)

{

  uint32_t length=  length_bytes == 1 ? (uint) *ptr : uint2korr(ptr);

  uint32_t local_char_length= max_key_length / field_charset->mbmaxlen;

  local_char_length= my_charpos(field_charset, ptr + length_bytes,

                          ptr + length_bytes + length, local_char_length);

  set_if_smaller(length, local_char_length);

  return field_charset->coll->strnncollsp(field_charset, 

                                          ptr + length_bytes,

                                          length,

                                          key_ptr+

                                          HA_KEY_BLOB_LENGTH,

                                          uint2korr(key_ptr), 0);

}

/**

  Compare to key segments (always 2 byte length prefix).

  @note

    This is used only to compare key segments created for index_read().

    (keys are created and compared in key.cc)

*/

int Field_varstring::key_cmp(const unsigned char *a,const unsigned char *b)

{

  return field_charset->coll->strnncollsp(field_charset,

                                          a + HA_KEY_BLOB_LENGTH,

                                          uint2korr(a),

                                          b + HA_KEY_BLOB_LENGTH,

                                          uint2korr(b),

                                          0);

}

void Field_varstring::sort_string(unsigned char *to,uint32_t length)

{

  uint32_t tot_length=  length_bytes == 1 ? (uint) *ptr : uint2korr(ptr);

  if (field_charset == &my_charset_bin)

  {

    /* Store length last in high-byte order to sort longer strings first */

    if (length_bytes == 1)

      to[length-1]= tot_length;

    else

      mi_int2store(to+length-2, tot_length);

    length-= length_bytes;

  }

  tot_length= my_strnxfrm(field_charset,

			  to, length, ptr + length_bytes,

			  tot_length);

  assert(tot_length == length);

}

enum ha_base_keytype Field_varstring::key_type() const

{

  enum ha_base_keytype res;

  if (binary())

    res= length_bytes == 1 ? HA_KEYTYPE_VARBINARY1 : HA_KEYTYPE_VARBINARY2;

  else

    res= length_bytes == 1 ? HA_KEYTYPE_VARTEXT1 : HA_KEYTYPE_VARTEXT2;

  return res;

}

void Field_varstring::sql_type(String &res) const

{

  const CHARSET_INFO * const cs=res.charset();

  uint32_t length;

  length= cs->cset->snprintf(cs,(char*) res.ptr(),

                             res.alloced_length(), "%s(%d)",

                              (has_charset() ? "varchar" : "varbinary"),

                             (int) field_length / charset()->mbmaxlen);

  res.length(length);

}

uint32_t Field_varstring::data_length()

{

  return length_bytes == 1 ? (uint32_t) *ptr : uint2korr(ptr);

}

uint32_t Field_varstring::used_length()

{

  return length_bytes == 1 ? 1 + (uint32_t) (unsigned char) *ptr : 2 + uint2korr(ptr);

}

/*

  Functions to create a packed row.

  Here the number of length bytes are depending on the given max_length

*/

unsigned char *Field_varstring::pack(unsigned char *to, const unsigned char *from,

                             uint32_t max_length,

                             bool low_byte_first __attribute__((unused)))

{

  uint32_t length= length_bytes == 1 ? (uint) *from : uint2korr(from);

  set_if_smaller(max_length, field_length);

  if (length > max_length)

    length=max_length;

  /* Length always stored little-endian */

  *to++= length & 0xFF;

  if (max_length > 255)

    *to++= (length >> 8) & 0xFF;

  /* Store bytes of string */

  if (length > 0)

    memcpy(to, from+length_bytes, length);

  return to+length;

}

unsigned char *

Field_varstring::pack_key(unsigned char *to, const unsigned char *key, uint32_t max_length,

                          bool low_byte_first __attribute__((unused)))

{

  uint32_t length=  length_bytes == 1 ? (uint) *key : uint2korr(key);

  uint32_t local_char_length= ((field_charset->mbmaxlen > 1) ?

                     max_length/field_charset->mbmaxlen : max_length);

  key+= length_bytes;

  if (length > local_char_length)

  {

    local_char_length= my_charpos(field_charset, key, key+length,

                                  local_char_length);

    set_if_smaller(length, local_char_length);

  }

  *to++= (char) (length & 255);

  if (max_length > 255)

    *to++= (char) (length >> 8);

  if (length)

    memcpy(to, key, length);

  return to+length;

}

/**

  Unpack a key into a record buffer.

  A VARCHAR key has a maximum size of 64K-1.

  In its packed form, the length field is one or two bytes long,

  depending on 'max_length'.

  @param to                          Pointer into the record buffer.

  @param key                         Pointer to the packed key.

  @param max_length                  Key length limit from key description.

  @return

    Pointer to end of 'key' (To the next key part if multi-segment key)

*/

const unsigned char *

Field_varstring::unpack_key(unsigned char *to __attribute__((unused)),

                            const unsigned char *key, uint32_t max_length,

                            bool low_byte_first __attribute__((unused)))

{

  /* get length of the blob key */

  uint32_t length= *key++;

  if (max_length > 255)

    length+= (*key++) << 8;

  /* put the length into the record buffer */

  if (length_bytes == 1)

    *ptr= (unsigned char) length;

  else

    int2store(ptr, length);

  memcpy(ptr + length_bytes, key, length);

  return key + length;

}

/**

  Create a packed key that will be used for storage in the index tree.

  @param to		Store packed key segment here

  @param from		Key segment (as given to index_read())

  @param max_length  	Max length of key

  @return

    end of key storage

*/

unsigned char *

Field_varstring::pack_key_from_key_image(unsigned char *to, const unsigned char *from, uint32_t max_length,

                                         bool low_byte_first __attribute__((unused)))

{

  /* Key length is always stored as 2 bytes */

  uint32_t length= uint2korr(from);

  if (length > max_length)

    length= max_length;

  *to++= (char) (length & 255);

  if (max_length > 255)

    *to++= (char) (length >> 8);

  if (length)

    memcpy(to, from+HA_KEY_BLOB_LENGTH, length);

  return to+length;

}

/**

   Unpack a varstring field from row data.

   This method is used to unpack a varstring field from a master

   whose size of the field is less than that of the slave.

   @note

   The string length is always packed little-endian.

   @param   to         Destination of the data

   @param   from       Source of the data

   @param   param_data Length bytes from the master's field data

   @return  New pointer into memory based on from + length of the data

*/

const unsigned char *

Field_varstring::unpack(unsigned char *to, const unsigned char *from,

                        uint32_t param_data,

                        bool low_byte_first __attribute__((unused)))

{

  uint32_t length;

  uint32_t l_bytes= (param_data && (param_data < field_length)) ? 

                (param_data <= 255) ? 1 : 2 : length_bytes;

  if (l_bytes == 1)

  {

    to[0]= *from++;

    length= to[0];

    if (length_bytes == 2)

      to[1]= 0;

  }

  else /* l_bytes == 2 */

  {

    length= uint2korr(from);

    to[0]= *from++;

    to[1]= *from++;

  }

  if (length)

    memcpy(to+ length_bytes, from, length);

  return from+length;

}

int Field_varstring::pack_cmp(const unsigned char *a, const unsigned char *b,

                              uint32_t key_length_arg,

                              bool insert_or_update)

{

  uint32_t a_length, b_length;

  if (key_length_arg > 255)

  {

    a_length=uint2korr(a); a+= 2;

    b_length=uint2korr(b); b+= 2;

  }

  else

  {

    a_length= (uint) *a++;

    b_length= (uint) *b++;

  }

  return field_charset->coll->strnncollsp(field_charset,

                                          a, a_length,

                                          b, b_length,

                                          insert_or_update);

}

int Field_varstring::pack_cmp(const unsigned char *b, uint32_t key_length_arg,

                              bool insert_or_update)

{

  unsigned char *a= ptr+ length_bytes;

  uint32_t a_length=  length_bytes == 1 ? (uint) *ptr : uint2korr(ptr);

  uint32_t b_length;

  uint32_t local_char_length= ((field_charset->mbmaxlen > 1) ?

                           key_length_arg / field_charset->mbmaxlen :

                           key_length_arg);

  if (key_length_arg > 255)

  {

    b_length=uint2korr(b); b+= HA_KEY_BLOB_LENGTH;

  }

  else

    b_length= (uint) *b++;

  if (a_length > local_char_length)

  {

    local_char_length= my_charpos(field_charset, a, a+a_length,

                                  local_char_length);

    set_if_smaller(a_length, local_char_length);

  }

  return field_charset->coll->strnncollsp(field_charset,

                                          a, a_length,

                                          b, b_length,

                                          insert_or_update);

}

uint32_t Field_varstring::packed_col_length(const unsigned char *data_ptr, uint32_t length)

{

  if (length > 255)

    return uint2korr(data_ptr)+2;

  return (uint) *data_ptr + 1;

}

uint32_t Field_varstring::max_packed_col_length(uint32_t max_length)

{

  return (max_length > 255 ? 2 : 1)+max_length;

}

uint32_t Field_varstring::get_key_image(unsigned char *buff,

                                    uint32_t length,

                                    imagetype type __attribute__((unused)))

{

  uint32_t f_length=  length_bytes == 1 ? (uint) *ptr : uint2korr(ptr);

  uint32_t local_char_length= length / field_charset->mbmaxlen;

  unsigned char *pos= ptr+length_bytes;

  local_char_length= my_charpos(field_charset, pos, pos + f_length,

                                local_char_length);

  set_if_smaller(f_length, local_char_length);

  /* Key is always stored with 2 bytes */

  int2store(buff,f_length);

  memcpy(buff+HA_KEY_BLOB_LENGTH, pos, f_length);

  if (f_length < length)

  {

    /*

      Must clear this as we do a memcmp in opt_range.cc to detect

      identical keys

    */

    memset(buff+HA_KEY_BLOB_LENGTH+f_length, 0, (length-f_length));

  }

  return HA_KEY_BLOB_LENGTH+f_length;

}

void Field_varstring::set_key_image(const unsigned char *buff,uint32_t length)

{

  length= uint2korr(buff);			// Real length is here

  (void) Field_varstring::store((const char*) buff+HA_KEY_BLOB_LENGTH, length,

                                field_charset);

}

int Field_varstring::cmp_binary(const unsigned char *a_ptr, const unsigned char *b_ptr,

                                uint32_t max_length)

{

  uint32_t a_length,b_length;

  if (length_bytes == 1)

  {

    a_length= (uint) *a_ptr;

    b_length= (uint) *b_ptr;

  }

  else

  {

    a_length= uint2korr(a_ptr);

    b_length= uint2korr(b_ptr);

  }

  set_if_smaller(a_length, max_length);

  set_if_smaller(b_length, max_length);

  if (a_length != b_length)

    return 1;

  return memcmp(a_ptr+length_bytes, b_ptr+length_bytes, a_length);

}

Field *Field_varstring::new_field(MEM_ROOT *root, Table *new_table, bool keep_type)

{

  Field_varstring *res= (Field_varstring*) Field::new_field(root, new_table,

                                                            keep_type);

  if (res)

    res->length_bytes= length_bytes;

  return res;

}

Field *Field_varstring::new_key_field(MEM_ROOT *root,

                                      Table *new_table,

                                      unsigned char *new_ptr, unsigned char *new_null_ptr,

                                      uint32_t new_null_bit)

{

  Field_varstring *res;

  if ((res= (Field_varstring*) Field::new_key_field(root,

                                                    new_table,

                                                    new_ptr,

                                                    new_null_ptr,

                                                    new_null_bit)))

  {

    /* Keys length prefixes are always packed with 2 bytes */

    res->length_bytes= 2;

  }

  return res;

}

uint32_t Field_varstring::is_equal(Create_field *new_field)

{

  if (new_field->sql_type == real_type() &&

      new_field->charset == field_charset)

  {

    if (new_field->length == max_display_length())

      return IS_EQUAL_YES;

    if (new_field->length > max_display_length() &&

	((new_field->length <= 255 && max_display_length() <= 255) ||

	 (new_field->length > 255 && max_display_length() > 255)))

      return IS_EQUAL_PACK_LENGTH; // VARCHAR, longer variable length

  }

  return IS_EQUAL_NO;

}

void Field_varstring::hash(uint32_t *nr, uint32_t *nr2)

{

  if (is_null())

  {

    *nr^= (*nr << 1) | 1;

  }

  else

  {

    uint32_t len=  length_bytes == 1 ? (uint) *ptr : uint2korr(ptr);

    const CHARSET_INFO * const cs= charset();

    cs->coll->hash_sort(cs, ptr + length_bytes, len, nr, nr2);

  }

}