diff options
Diffstat (limited to 'sql/field_conv.cc')
-rw-r--r-- | sql/field_conv.cc | 873 |
1 files changed, 873 insertions, 0 deletions
diff --git a/sql/field_conv.cc b/sql/field_conv.cc new file mode 100644 index 00000000..ff6d60e7 --- /dev/null +++ b/sql/field_conv.cc @@ -0,0 +1,873 @@ +/* Copyright (c) 2000, 2016, Oracle and/or its affiliates. + Copyright (c) 2010, 2020, MariaDB Corporation + + 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 02110-1335 USA */ + + +/** + @file + + @brief + Functions to copy data to or from fields + + This could be done with a single short function but opencoding this + gives much more speed. +*/ + +#include "mariadb.h" +#include "sql_priv.h" +#include "sql_class.h" // THD +#include <m_ctype.h> + +void Field::do_field_eq(Copy_field *copy) +{ + memcpy(copy->to_ptr,copy->from_ptr,copy->from_length); +} + +static void do_field_1(Copy_field *copy) +{ + copy->to_ptr[0]=copy->from_ptr[0]; +} + +static void do_field_2(Copy_field *copy) +{ + copy->to_ptr[0]=copy->from_ptr[0]; + copy->to_ptr[1]=copy->from_ptr[1]; +} + +static void do_field_3(Copy_field *copy) +{ + copy->to_ptr[0]=copy->from_ptr[0]; + copy->to_ptr[1]=copy->from_ptr[1]; + copy->to_ptr[2]=copy->from_ptr[2]; +} + +static void do_field_4(Copy_field *copy) +{ + copy->to_ptr[0]=copy->from_ptr[0]; + copy->to_ptr[1]=copy->from_ptr[1]; + copy->to_ptr[2]=copy->from_ptr[2]; + copy->to_ptr[3]=copy->from_ptr[3]; +} + +static void do_field_6(Copy_field *copy) +{ // For blob field + copy->to_ptr[0]=copy->from_ptr[0]; + copy->to_ptr[1]=copy->from_ptr[1]; + copy->to_ptr[2]=copy->from_ptr[2]; + copy->to_ptr[3]=copy->from_ptr[3]; + copy->to_ptr[4]=copy->from_ptr[4]; + copy->to_ptr[5]=copy->from_ptr[5]; +} + +static void do_field_8(Copy_field *copy) +{ + copy->to_ptr[0]=copy->from_ptr[0]; + copy->to_ptr[1]=copy->from_ptr[1]; + copy->to_ptr[2]=copy->from_ptr[2]; + copy->to_ptr[3]=copy->from_ptr[3]; + copy->to_ptr[4]=copy->from_ptr[4]; + copy->to_ptr[5]=copy->from_ptr[5]; + copy->to_ptr[6]=copy->from_ptr[6]; + copy->to_ptr[7]=copy->from_ptr[7]; +} + + +static void do_field_to_null_str(Copy_field *copy) +{ + if (*copy->from_null_ptr & copy->from_bit) + { + bzero(copy->to_ptr,copy->from_length); + copy->to_null_ptr[0]=1; // Always bit 1 + } + else + { + copy->to_null_ptr[0]=0; + memcpy(copy->to_ptr,copy->from_ptr,copy->from_length); + } +} + + +static void do_outer_field_to_null_str(Copy_field *copy) +{ + if (*copy->null_row || + (copy->from_null_ptr && (*copy->from_null_ptr & copy->from_bit))) + { + bzero(copy->to_ptr,copy->from_length); + copy->to_null_ptr[0]=1; // Always bit 1 + } + else + { + copy->to_null_ptr[0]=0; + memcpy(copy->to_ptr,copy->from_ptr,copy->from_length); + } +} + + +static int set_bad_null_error(Field *field, int err) +{ + switch (field->table->in_use->count_cuted_fields) { + case CHECK_FIELD_WARN: + field->set_warning(Sql_condition::WARN_LEVEL_WARN, err, 1); + /* fall through */ + case CHECK_FIELD_IGNORE: + case CHECK_FIELD_EXPRESSION: + return 0; + case CHECK_FIELD_ERROR_FOR_NULL: + if (!field->table->in_use->no_errors) + my_error(ER_BAD_NULL_ERROR, MYF(0), field->field_name.str); + return -1; + } + DBUG_ASSERT(0); // impossible + return -1; +} + + +int set_field_to_null(Field *field) +{ + if (field->table->null_catch_flags & CHECK_ROW_FOR_NULLS_TO_REJECT) + { + field->table->null_catch_flags|= REJECT_ROW_DUE_TO_NULL_FIELDS; + return -1; + } + if (field->real_maybe_null()) + { + field->set_null(); + field->reset(); + return 0; + } + field->reset(); + return set_bad_null_error(field, WARN_DATA_TRUNCATED); +} + + +/** + Set TIMESTAMP to NOW(), AUTO_INCREMENT to the next number, or report an error + + @param field Field to update + + @retval + 0 Field could take 0 or an automatic conversion was used + @retval + -1 Field could not take NULL and no conversion was used. + If no_conversion was not set, an error message is printed +*/ + +int convert_null_to_field_value_or_error(Field *field) +{ + if (field->type() == MYSQL_TYPE_TIMESTAMP) + { + field->set_time(); + return 0; + } + + field->reset(); // Note: we ignore any potential failure of reset() here. + + if (field == field->table->next_number_field) + { + field->table->auto_increment_field_not_null= FALSE; + return 0; // field is set in fill_record() + } + return set_bad_null_error(field, ER_BAD_NULL_ERROR); +} + +/** + Set field to NULL or TIMESTAMP or to next auto_increment number. + + @param field Field to update + @param no_conversions Set to 1 if we should return 1 if field can't + take null values. + If set to 0 we will do store the 'default value' + if the field is a special field. If not we will + give an error. + + @retval + 0 Field could take 0 or an automatic conversion was used + @retval + -1 Field could not take NULL and no conversion was used. + If no_conversion was not set, an error message is printed +*/ + +int +set_field_to_null_with_conversions(Field *field, bool no_conversions) +{ + if (field->table->null_catch_flags & CHECK_ROW_FOR_NULLS_TO_REJECT) + { + field->table->null_catch_flags|= REJECT_ROW_DUE_TO_NULL_FIELDS; + return -1; + } + if (field->real_maybe_null()) + { + field->set_null(); + field->reset(); + return 0; + } + if (no_conversions) + return -1; + + return convert_null_to_field_value_or_error(field); +} + + +static void do_skip(Copy_field *copy __attribute__((unused))) +{ +} + + +/* + Copy: (NULLable field) -> (NULLable field) + + note: if the record we're copying from is NULL-complemetned (i.e. + from_field->table->null_row==1), it will also have all NULLable columns to be + set to NULLs, so we don't need to check table->null_row here. +*/ + +static void do_copy_null(Copy_field *copy) +{ + if (*copy->from_null_ptr & copy->from_bit) + { + *copy->to_null_ptr|=copy->to_bit; + copy->to_field->reset(); + } + else + { + *copy->to_null_ptr&= ~copy->to_bit; + (copy->do_copy2)(copy); + } +} + +/* + Copy: (not-NULL field in table that can be NULL-complemented) -> (NULLable + field) +*/ + +static void do_outer_field_null(Copy_field *copy) +{ + if (*copy->null_row || + (copy->from_null_ptr && (*copy->from_null_ptr & copy->from_bit))) + { + *copy->to_null_ptr|=copy->to_bit; + copy->to_field->reset(); + } + else + { + *copy->to_null_ptr&= ~copy->to_bit; + (copy->do_copy2)(copy); + } +} + +/* + Copy: (not-NULL field in table that can be NULL-complemented) -> (not-NULL + field) +*/ +static void do_copy_nullable_row_to_notnull(Copy_field *copy) +{ + if (*copy->null_row || + (copy->from_null_ptr && (*copy->from_null_ptr & copy->from_bit))) + { + copy->to_field->set_warning(Sql_condition::WARN_LEVEL_WARN, + WARN_DATA_TRUNCATED, 1); + copy->to_field->reset(); + } + else + { + (copy->do_copy2)(copy); + } + +} + +/* Copy: (NULL-able field) -> (not NULL-able field) */ +static void do_copy_not_null(Copy_field *copy) +{ + if (*copy->from_null_ptr & copy->from_bit) + { + copy->to_field->set_warning(Sql_condition::WARN_LEVEL_WARN, + WARN_DATA_TRUNCATED, 1); + copy->to_field->reset(); + } + else + (copy->do_copy2)(copy); +} + + +/* Copy: (non-NULLable field) -> (NULLable field) */ +static void do_copy_maybe_null(Copy_field *copy) +{ + *copy->to_null_ptr&= ~copy->to_bit; + (copy->do_copy2)(copy); +} + +/* timestamp and next_number has special handling in case of NULL values */ + +static void do_copy_timestamp(Copy_field *copy) +{ + if (*copy->from_null_ptr & copy->from_bit) + { + /* Same as in set_field_to_null_with_conversions() */ + copy->to_field->set_time(); + } + else + (copy->do_copy2)(copy); +} + + +static void do_copy_next_number(Copy_field *copy) +{ + if (*copy->from_null_ptr & copy->from_bit) + { + /* Same as in set_field_to_null_with_conversions() */ + copy->to_field->table->auto_increment_field_not_null= FALSE; + copy->to_field->reset(); + } + else + (copy->do_copy2)(copy); +} + + +void Field_blob::do_copy_blob(Copy_field *copy) +{ + ((Field_blob*) copy->to_field)->copy_value(((Field_blob*) copy->from_field)); +} + +void Field_blob::do_conv_blob(Copy_field *copy) +{ + copy->from_field->val_str(©->tmp); + ((Field_blob *) copy->to_field)->store(copy->tmp.ptr(), + copy->tmp.length(), + copy->tmp.charset()); +} + +/** Save blob in copy->tmp for GROUP BY. */ + +static void do_save_blob(Copy_field *copy) +{ + char buff[MAX_FIELD_WIDTH]; + String res(buff,sizeof(buff),copy->tmp.charset()); + copy->from_field->val_str(&res); + copy->tmp.copy(res); + ((Field_blob *) copy->to_field)->store(copy->tmp.ptr(), + copy->tmp.length(), + copy->tmp.charset()); +} + + +void Field::do_field_string(Copy_field *copy) +{ + char buff[MAX_FIELD_WIDTH]; + String res(buff, sizeof(buff), copy->from_field->charset()); + res.length(0U); + + copy->from_field->val_str(&res); + copy->to_field->store(res.c_ptr_quick(), res.length(), res.charset()); +} + + +void Field_enum::do_field_enum(Copy_field *copy) +{ + if (copy->from_field->val_int() == 0) + ((Field_enum *) copy->to_field)->store_type((ulonglong) 0); + else + do_field_string(copy); +} + + +static void do_field_varbinary_pre50(Copy_field *copy) +{ + char buff[MAX_FIELD_WIDTH]; + copy->tmp.set_quick(buff,sizeof(buff),copy->tmp.charset()); + copy->from_field->val_str(©->tmp); + + /* Use the same function as in 4.1 to trim trailing spaces */ + size_t length= my_lengthsp_8bit(&my_charset_bin, copy->tmp.c_ptr_quick(), + copy->from_field->field_length); + + copy->to_field->store(copy->tmp.c_ptr_quick(), length, + copy->tmp.charset()); +} + + +void Field::do_field_int(Copy_field *copy) +{ + longlong value= copy->from_field->val_int(); + copy->to_field->store(value, + MY_TEST(copy->from_field->flags & UNSIGNED_FLAG)); +} + +void Field::do_field_real(Copy_field *copy) +{ + double value=copy->from_field->val_real(); + copy->to_field->store(value); +} + + +void Field::do_field_decimal(Copy_field *copy) +{ + my_decimal value(copy->from_field); + copy->to_field->store_decimal(&value); +} + + +void Field::do_field_timestamp(Copy_field *copy) +{ + // XXX why couldn't we do it everywhere? + copy->from_field->save_in_field(copy->to_field); +} + + +void Field::do_field_temporal(Copy_field *copy, date_mode_t fuzzydate) +{ + MYSQL_TIME ltime; + // TODO: we now need to check result + if (copy->from_field->get_date(<ime, fuzzydate)) + copy->to_field->reset(); + else + copy->to_field->store_time_dec(<ime, copy->from_field->decimals()); +} + + +void Field::do_field_datetime(Copy_field *copy) +{ + return do_field_temporal(copy, Datetime::Options(TIME_CONV_NONE, current_thd)); +} + + +void Field::do_field_date(Copy_field *copy) +{ + return do_field_temporal(copy, Date::Options(TIME_CONV_NONE)); +} + + +void Field_time::do_field_time(Copy_field *copy) +{ + return do_field_temporal(copy, Time::Options(current_thd)); +} + + +/** + string copy for single byte characters set when to string is shorter than + from string. +*/ + +static void do_cut_string(Copy_field *copy) +{ + CHARSET_INFO *cs= copy->from_field->charset(); + memcpy(copy->to_ptr,copy->from_ptr,copy->to_length); + + /* Check if we loosed any important characters */ + if (cs->scan((char*) copy->from_ptr + copy->to_length, + (char*) copy->from_ptr + copy->from_length, + MY_SEQ_SPACES) < copy->from_length - copy->to_length) + { + copy->to_field->set_warning(Sql_condition::WARN_LEVEL_WARN, + WARN_DATA_TRUNCATED, 1); + } +} + + +/** + string copy for multi byte characters set when to string is shorter than + from string. +*/ + +static void do_cut_string_complex(Copy_field *copy) +{ // Shorter string field + CHARSET_INFO *cs= copy->from_field->charset(); + const uchar *from_end= copy->from_ptr + copy->from_length; + Well_formed_prefix prefix(cs, + (char*) copy->from_ptr, + (char*) from_end, + copy->to_length / cs->mbmaxlen); + size_t copy_length= prefix.length(); + if (copy->to_length < copy_length) + copy_length= copy->to_length; + memcpy(copy->to_ptr, copy->from_ptr, copy_length); + + /* Check if we lost any important characters */ + if (unlikely(prefix.well_formed_error_pos() || + cs->scan((char*) copy->from_ptr + copy_length, + (char*) from_end, + MY_SEQ_SPACES) < + (copy->from_length - copy_length))) + { + copy->to_field->set_warning(Sql_condition::WARN_LEVEL_WARN, + WARN_DATA_TRUNCATED, 1); + } + + if (copy_length < copy->to_length) + cs->fill((char*) copy->to_ptr + copy_length, + copy->to_length - copy_length, ' '); +} + + + + +static void do_expand_binary(Copy_field *copy) +{ + CHARSET_INFO *cs= copy->from_field->charset(); + memcpy(copy->to_ptr,copy->from_ptr,copy->from_length); + cs->fill((char*) copy->to_ptr+copy->from_length, + copy->to_length-copy->from_length, '\0'); +} + + + +static void do_expand_string(Copy_field *copy) +{ + CHARSET_INFO *cs= copy->from_field->charset(); + memcpy(copy->to_ptr,copy->from_ptr,copy->from_length); + cs->fill((char*) copy->to_ptr+copy->from_length, + copy->to_length-copy->from_length, ' '); +} + + +static void do_varstring1(Copy_field *copy) +{ + uint length= (uint) *(uchar*) copy->from_ptr; + if (length > copy->to_length- 1) + { + length=copy->to_length - 1; + if (copy->from_field->table->in_use->count_cuted_fields > + CHECK_FIELD_EXPRESSION && + copy->to_field) + copy->to_field->set_warning(Sql_condition::WARN_LEVEL_WARN, + WARN_DATA_TRUNCATED, 1); + } + *(uchar*) copy->to_ptr= (uchar) length; + memcpy(copy->to_ptr+1, copy->from_ptr + 1, length); +} + + +static void do_varstring1_mb(Copy_field *copy) +{ + CHARSET_INFO *cs= copy->from_field->charset(); + uint from_length= (uint) *(uchar*) copy->from_ptr; + const uchar *from_ptr= copy->from_ptr + 1; + uint to_char_length= (copy->to_length - 1) / cs->mbmaxlen; + Well_formed_prefix prefix(cs, (char*) from_ptr, from_length, to_char_length); + if (prefix.length() < from_length) + { + if (current_thd->count_cuted_fields > CHECK_FIELD_EXPRESSION) + copy->to_field->set_warning(Sql_condition::WARN_LEVEL_WARN, + WARN_DATA_TRUNCATED, 1); + } + *copy->to_ptr= (uchar) prefix.length(); + memcpy(copy->to_ptr + 1, from_ptr, prefix.length()); +} + + +static void do_varstring2(Copy_field *copy) +{ + uint length=uint2korr(copy->from_ptr); + if (length > copy->to_length- HA_KEY_BLOB_LENGTH) + { + length=copy->to_length-HA_KEY_BLOB_LENGTH; + if (copy->from_field->table->in_use->count_cuted_fields > + CHECK_FIELD_EXPRESSION && + copy->to_field) + copy->to_field->set_warning(Sql_condition::WARN_LEVEL_WARN, + WARN_DATA_TRUNCATED, 1); + } + int2store(copy->to_ptr,length); + memcpy(copy->to_ptr+HA_KEY_BLOB_LENGTH, copy->from_ptr + HA_KEY_BLOB_LENGTH, + length); +} + + +static void do_varstring2_mb(Copy_field *copy) +{ + CHARSET_INFO *cs= copy->from_field->charset(); + uint char_length= (copy->to_length - HA_KEY_BLOB_LENGTH) / cs->mbmaxlen; + uint from_length= uint2korr(copy->from_ptr); + const uchar *from_beg= copy->from_ptr + HA_KEY_BLOB_LENGTH; + Well_formed_prefix prefix(cs, (char*) from_beg, from_length, char_length); + if (prefix.length() < from_length) + { + if (current_thd->count_cuted_fields > CHECK_FIELD_EXPRESSION) + copy->to_field->set_warning(Sql_condition::WARN_LEVEL_WARN, + WARN_DATA_TRUNCATED, 1); + } + int2store(copy->to_ptr, prefix.length()); + memcpy(copy->to_ptr+HA_KEY_BLOB_LENGTH, from_beg, prefix.length()); +} + + +/*************************************************************************** +** The different functions that fills in a Copy_field class +***************************************************************************/ + +/** + copy of field to maybe null string. + If field is null then the all bytes are set to 0. + if field is not null then the first byte is set to 1 and the rest of the + string is the field value. + The 'to' buffer should have a size of field->pack_length()+1 +*/ + +void Copy_field::set(uchar *to,Field *from) +{ + from_ptr=from->ptr; + to_ptr=to; + from_length=from->pack_length_in_rec(); + if (from->maybe_null()) + { + from_null_ptr=from->null_ptr; + from_bit= from->null_bit; + to_ptr[0]= 1; // Null as default value + to_null_ptr= (uchar*) to_ptr++; + to_bit= 1; + if (from->table->maybe_null) + { + null_row= &from->table->null_row; + do_copy= do_outer_field_to_null_str; + } + else + do_copy= do_field_to_null_str; + } + else + { + to_null_ptr= 0; // For easy debugging + do_copy= Field::do_field_eq; + } +} + + +/* + To do: + + If 'save' is set to true and the 'from' is a blob field, do_copy is set to + do_save_blob rather than do_conv_blob. The only differences between them + appears to be: + + - do_save_blob allocates and uses an intermediate buffer before calling + Field_blob::store. Is this in order to trigger the call to + well_formed_copy_nchars, by changing the pointer copy->tmp.ptr()? + That call will take place anyway in all known cases. + */ +void Copy_field::set(Field *to,Field *from,bool save) +{ + if (to->type() == MYSQL_TYPE_NULL) + { + to_null_ptr=0; // For easy debugging + to_ptr=0; + do_copy=do_skip; + return; + } + from_field=from; + to_field=to; + from_ptr=from->ptr; + from_length=from->pack_length_in_rec(); + to_ptr= to->ptr; + to_length=to_field->pack_length_in_rec(); + + // set up null handling + from_null_ptr=to_null_ptr=0; + if (from->maybe_null()) + { + from_null_ptr= from->null_ptr; + from_bit= from->null_bit; + if (to_field->real_maybe_null()) + { + to_null_ptr= to->null_ptr; + to_bit= to->null_bit; + if (from_null_ptr) + do_copy= do_copy_null; + else + { + null_row= &from->table->null_row; + do_copy= do_outer_field_null; + } + } + else + { + if (to_field->type() == MYSQL_TYPE_TIMESTAMP) + do_copy= do_copy_timestamp; // Automatic timestamp + else if (to_field == to_field->table->next_number_field) + do_copy= do_copy_next_number; + else + { + if (!from_null_ptr) + { + null_row= &from->table->null_row; + do_copy= do_copy_nullable_row_to_notnull; + } + else + do_copy= do_copy_not_null; + } + } + } + else if (to_field->real_maybe_null()) + { + to_null_ptr= to->null_ptr; + to_bit= to->null_bit; + do_copy= do_copy_maybe_null; + } + else + do_copy=0; + + if ((to->flags & BLOB_FLAG) && save) + do_copy2= do_save_blob; + else + do_copy2= from->get_copy_func_to(to); + if (!do_copy) // Not null + do_copy=do_copy2; +} + + +Field::Copy_func *Field_timestamp::get_copy_func(const Field *from) const +{ + Field::Copy_func *copy= Field_temporal::get_copy_func(from); + if (copy == do_field_datetime && from->type() == MYSQL_TYPE_TIMESTAMP) + return do_field_timestamp; + else + return copy; +} + + +Field::Copy_func *Field_date_common::get_copy_func(const Field *from) const +{ + Field::Copy_func *copy= Field_temporal::get_copy_func(from); + return copy == do_field_datetime ? do_field_date : copy; +} + + +Field::Copy_func *Field_temporal::get_copy_func(const Field *from) const +{ + /* If types are not 100 % identical then convert trough get_date() */ + if (from->cmp_type() == REAL_RESULT) + return do_field_string; // TODO: MDEV-9344 + if (from->type() == MYSQL_TYPE_YEAR) + return do_field_string; // TODO: MDEV-9343 + if (from->type() == MYSQL_TYPE_BIT) + return do_field_int; + if (!eq_def(from) || + (table->in_use->variables.sql_mode & + (MODE_NO_ZERO_IN_DATE | MODE_NO_ZERO_DATE))) + return do_field_datetime; + return get_identical_copy_func(); +} + + +Field::Copy_func *Field_varstring::get_copy_func(const Field *from) const +{ + if (from->type() == MYSQL_TYPE_BIT) + return do_field_int; + /* + Detect copy from pre 5.0 varbinary to varbinary as of 5.0 and + use special copy function that removes trailing spaces and thus + repairs data. + */ + if (from->type() == MYSQL_TYPE_VAR_STRING && !from->has_charset() && + !Field_varstring::has_charset()) + return do_field_varbinary_pre50; + if (Field_varstring::real_type() != from->real_type() || + Field_varstring::charset() != from->charset() || + length_bytes != ((const Field_varstring*) from)->length_bytes || + !compression_method() != !from->compression_method()) + return do_field_string; + return length_bytes == 1 ? + (from->charset()->mbmaxlen == 1 ? do_varstring1 : do_varstring1_mb) : + (from->charset()->mbmaxlen == 1 ? do_varstring2 : do_varstring2_mb); +} + + +Field::Copy_func *Field_string::get_copy_func(const Field *from) const +{ + if (from->type() == MYSQL_TYPE_BIT) + return do_field_int; + if (Field_string::type_handler() != from->type_handler() || + Field_string::charset() != from->charset()) + return do_field_string; + if (Field_string::pack_length() < from->pack_length()) + return (Field_string::charset()->mbmaxlen == 1 ? + do_cut_string : do_cut_string_complex); + if (Field_string::pack_length() > from->pack_length()) + return Field_string::charset() == &my_charset_bin ? do_expand_binary : + do_expand_string; + return get_identical_copy_func(); +} + + +Field::Copy_func *Field::get_identical_copy_func() const +{ + /* Identical field types */ + switch (pack_length()) { + case 1: return do_field_1; + case 2: return do_field_2; + case 3: return do_field_3; + case 4: return do_field_4; + case 6: return do_field_6; + case 8: return do_field_8; + } + return do_field_eq; +} + + +bool Field_temporal::memcpy_field_possible(const Field *from) const +{ + return real_type() == from->real_type() && + decimals() == from->decimals() && + !sql_mode_for_dates(table->in_use); +} + + +static int field_conv_memcpy(Field *to, Field *from) +{ + /* + This may happen if one does 'UPDATE ... SET x=x' + The test is here mostly for valgrind, but can also be relevant + if memcpy() is implemented with prefetch-write + */ + if (to->ptr != from->ptr) + memcpy(to->ptr,from->ptr, to->pack_length()); + return 0; +} + + +/** + Copy value of the field with conversion. + + @note Impossibility of simple copy should be checked before this call. + + @param to The field to copy to + + @retval TRUE ERROR + @retval FALSE OK + +*/ +static int field_conv_incompatible(Field *to, Field *from) +{ + return to->store_field(from); +} + + +/** + Simple quick field converter that is called on insert, e.g.: + INSERT INTO t1 (field1) SELECT field2 FROM t2; +*/ + +int field_conv(Field *to,Field *from) +{ + return to->memcpy_field_possible(from) ? + field_conv_memcpy(to, from) : + field_conv_incompatible(to, from); +} + + +fast_field_copier Field::get_fast_field_copier(const Field *from) +{ + DBUG_ENTER("Field::get_fast_field_copier"); + DBUG_RETURN(memcpy_field_possible(from) ? + &field_conv_memcpy : + &field_conv_incompatible); +} |