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Reducing duplicate code and simplifying well formed string copying

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by adding a new class String_copier.

This is a pre-requisite patch for MDEV-6566 and MDEV-6572,
to avoid adding more similar code.
This commit is contained in:
Alexander Barkov
2015-02-27 16:26:12 +04:00
parent 2d01907c1d
commit 72d7b12b9c
7 changed files with 164 additions and 152 deletions
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105
sql/sql_string.cc
View File

@ -875,41 +875,44 @@ my_copy_with_hex_escaping(CHARSET_INFO *cs,
/*
copy a string,
Copy a string,
with optional character set conversion,
with optional left padding (for binary -> UCS2 conversion)
SYNOPSIS
well_formed_copy_nchars()
to Store result here
to_length Maxinum length of "to" string
to_cs Character set of "to" string
from Copy from here
from_length Length of from string
from_cs From character set
nchars Copy not more that nchars characters
well_formed_error_pos Return position when "from" is not well formed
In case if there is a Unicode conversion (i.e. to_cs and from_cs are
different character sets and both are not &my_charset_bin), bad input bytes
as well as characters that cannot be encoded in to_cs are replaced to '?'.
In case of non-Unicode copying (i.e. to_cs and from_cs are same character set,
or from_cs is &my_charset_bin), the function stops on the first bad
byte sequence.
The string that is written to "to" is always well-formed.
@param to The destination string
@param to_length Space available in "to"
@param to_cs Character set of the "to" string
@param from The source string
@param from_length Length of the "from" string
@param from_cs Character set of the "from" string
@param nchars Copy not more than "nchars" characters
The members as set as follows:
m_well_formed_error_pos To the position when "from" is not well formed
or NULL otherwise.
cannot_convert_error_pos Return position where a not convertable
m_cannot_convert_error_pos To the position where a not convertable
character met, or NULL otherwise.
from_end_pos Return position where scanning of "from"
m_source_end_pos To the position where scanning of the "from"
string stopped.
NOTES
RETURN
length of bytes copied to 'to'
@returns number of bytes that were written to 'to'
*/
uint32
well_formed_copy_nchars(CHARSET_INFO *to_cs,
char *to, uint to_length,
CHARSET_INFO *from_cs,
const char *from, uint from_length,
uint nchars,
const char **well_formed_error_pos,
const char **cannot_convert_error_pos,
const char **from_end_pos)
uint
String_copier::well_formed_copy(CHARSET_INFO *to_cs,
char *to, uint to_length,
CHARSET_INFO *from_cs,
const char *from, uint from_length,
uint nchars)
{
uint res;
@ -920,9 +923,9 @@ well_formed_copy_nchars(CHARSET_INFO *to_cs,
{
if (to_length < to_cs->mbminlen || !nchars)
{
*from_end_pos= from;
*cannot_convert_error_pos= NULL;
*well_formed_error_pos= NULL;
m_source_end_pos= from;
m_cannot_convert_error_pos= NULL;
m_well_formed_error_pos= NULL;
return 0;
}
@ -930,9 +933,9 @@ well_formed_copy_nchars(CHARSET_INFO *to_cs,
{
res= MY_MIN(MY_MIN(nchars, to_length), from_length);
memmove(to, from, res);
*from_end_pos= from + res;
*well_formed_error_pos= NULL;
*cannot_convert_error_pos= NULL;
m_source_end_pos= from + res;
m_well_formed_error_pos= NULL;
m_cannot_convert_error_pos= NULL;
}
else
{
@ -964,8 +967,8 @@ well_formed_copy_nchars(CHARSET_INFO *to_cs,
&well_formed_error) !=
to_cs->mbminlen)
{
*from_end_pos= *well_formed_error_pos= from;
*cannot_convert_error_pos= NULL;
m_source_end_pos= m_well_formed_error_pos= from;
m_cannot_convert_error_pos= NULL;
return 0;
}
nchars--;
@ -979,9 +982,9 @@ well_formed_copy_nchars(CHARSET_INFO *to_cs,
res= to_cs->cset->well_formed_len(to_cs, from, from + from_length,
nchars, &well_formed_error);
memmove(to, from, res);
*from_end_pos= from + res;
*well_formed_error_pos= well_formed_error ? from + res : NULL;
*cannot_convert_error_pos= NULL;
m_source_end_pos= from + res;
m_well_formed_error_pos= well_formed_error ? from + res : NULL;
m_cannot_convert_error_pos= NULL;
if (from_offset)
res+= to_cs->mbminlen;
}
@ -995,8 +998,8 @@ well_formed_copy_nchars(CHARSET_INFO *to_cs,
const uchar *from_end= (const uchar*) from + from_length;
uchar *to_end= (uchar*) to + to_length;
char *to_start= to;
*well_formed_error_pos= NULL;
*cannot_convert_error_pos= NULL;
m_well_formed_error_pos= NULL;
m_cannot_convert_error_pos= NULL;
for ( ; nchars; nchars--)
{
@ -1005,8 +1008,8 @@ well_formed_copy_nchars(CHARSET_INFO *to_cs,
from+= cnvres;
else if (cnvres == MY_CS_ILSEQ)
{
if (!*well_formed_error_pos)
*well_formed_error_pos= from;
if (!m_well_formed_error_pos)
m_well_formed_error_pos= from;
from++;
wc= '?';
}
@ -1016,8 +1019,8 @@ well_formed_copy_nchars(CHARSET_INFO *to_cs,
A correct multibyte sequence detected
But it doesn't have Unicode mapping.
*/
if (!*cannot_convert_error_pos)
*cannot_convert_error_pos= from;
if (!m_cannot_convert_error_pos)
m_cannot_convert_error_pos= from;
from+= (-cnvres);
wc= '?';
}
@ -1026,8 +1029,8 @@ well_formed_copy_nchars(CHARSET_INFO *to_cs,
if ((uchar *) from >= from_end)
break; // End of line
// Incomplete byte sequence
if (!*well_formed_error_pos)
*well_formed_error_pos= from;
if (!m_well_formed_error_pos)
m_well_formed_error_pos= from;
from++;
wc= '?';
}
@ -1036,8 +1039,8 @@ outp:
to+= cnvres;
else if (cnvres == MY_CS_ILUNI && wc != '?')
{
if (!*cannot_convert_error_pos)
*cannot_convert_error_pos= from_prev;
if (!m_cannot_convert_error_pos)
m_cannot_convert_error_pos= from_prev;
wc= '?';
goto outp;
}
@ -1047,10 +1050,10 @@ outp:
break;
}
}
*from_end_pos= from;
m_source_end_pos= from;
res= (uint) (to - to_start);
}
return (uint32) res;
return res;
}