utils/common/collation.h

/*
   Copyright (C) 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 Street, Fifth Floor, Boston,
   MA 02110-1301, USA. */
#ifndef COLLATION_H_INCLUDED
#define COLLATION_H_INCLUDED

#include "mcsconfig.h"
#include "exceptclasses.h"
#include "conststring.h"

/*
  Redefine definitions used by MariaDB m_ctype.h.
  This is needed to avoid including <mariadb.h> and <my_sys.h>,
  which conflict with many MCS and boost headers.
*/

#ifndef FALSE
#define FALSE (0)
#endif

#ifndef TRUE
#define TRUE  (1)
#endif

#ifndef DBUG_ASSERT
#define DBUG_ASSERT(x)  idbassert(x)
#define DBUG_ASSERT_TEMPORARILY_DEFINED
#endif

#ifndef MYSQL_PLUGIN_IMPORT
#if (defined(_WIN32) && defined(MYSQL_DYNAMIC_PLUGIN))
#define MYSQL_PLUGIN_IMPORT __declspec(dllimport)
#else
#define MYSQL_PLUGIN_IMPORT
#endif
#endif

typedef long long int longlong;
typedef unsigned long long int ulonglong;
typedef uint32_t uint32;
typedef uint16_t uint16;
typedef char my_bool;
typedef unsigned char uchar;

#if defined(__GNUC__) && !defined(_lint)
typedef char	pchar;		/* Mixed prototypes can take char */
typedef char	puchar;		/* Mixed prototypes can take char */
typedef char	pbool;		/* Mixed prototypes can take char */
typedef short	pshort;		/* Mixed prototypes can take short int */
typedef float	pfloat;		/* Mixed prototypes can take float */
#else
typedef int	pchar;		/* Mixed prototypes can't take char */
typedef uint	puchar;		/* Mixed prototypes can't take char */
typedef int	pbool;		/* Mixed prototypes can't take char */
typedef int	pshort;		/* Mixed prototypes can't take short int */
typedef double	pfloat;		/* Mixed prototypes can't take float */
#endif

typedef const struct charset_info_st CHARSET_INFO;
extern "C" MYSQL_PLUGIN_IMPORT CHARSET_INFO *default_charset_info;

#include "my_compiler.h"
#include "m_ctype.h"

#undef FALSE
#undef TRUE

#ifdef DBUG_ASSERT_TEMPORARILY_DEFINED
#undef DBUG_ASSERT
#endif


namespace datatypes
{

class MariaDBHasher
{
    static const ulong mPart1DefValue = 1;
    static const ulong mPart2DefValue = 4;

    ulong mPart1;
    ulong mPart2;
public:
    MariaDBHasher()
        :mPart1(mPart1DefValue), mPart2(mPart2DefValue)
    { }
    MariaDBHasher & add(CHARSET_INFO * cs, const char *str, size_t length)
    {
        cs->hash_sort((const uchar *) str, length, &mPart1, &mPart2);
        return *this;
    }
    MariaDBHasher & add(CHARSET_INFO *cs, const utils::ConstString &str)
    {
        return add(cs, str.str(), str.length());
    }
    uint64_t finalize() const
    {
        return mPart1;
    }
    bool wasUsed() const
    {
        return mPart1 != mPart1DefValue || mPart2 != mPart2DefValue;
    }
};


// A reference to MariaDB CHARSET_INFO.

class Charset
{
protected:
    const struct charset_info_st * mCharset;
public:
    Charset(CHARSET_INFO & cs) :mCharset(&cs) { }
    Charset(CHARSET_INFO *cs)
       :mCharset(cs ? cs : &my_charset_bin)
    { }
    Charset(uint32_t charsetNumber);
    CHARSET_INFO & getCharset() const { return *mCharset; }
    uint32_t hash(const char *data, uint64_t len) const
    {
        return MariaDBHasher().add(mCharset, data, len).finalize();
    }
    bool eq(const std::string & str1, const std::string & str2) const
    {
        return mCharset->strnncollsp(str1.data(), str1.length(),
                                     str2.data(), str2.length()) == 0;
    }
    int strnncollsp(const utils::ConstString &str1,
                    const utils::ConstString &str2) const
    {
        return mCharset->strnncollsp(str1.str(), str1.length(),
                                     str2.str(), str2.length());
    }
    int strnncollsp(const char *str1, size_t length1,
                    const char *str2, size_t length2) const
    {
      return mCharset->strnncollsp(str1, length1, str2, length2);
    }
    int strnncollsp(const unsigned char *str1, size_t length1,
                    const unsigned char *str2, size_t length2) const
    {
      return mCharset->strnncollsp((const char *) str1, length1,
                                   (const char *) str2, length2);
    }
    bool test_if_important_data(const char *str, const char *end) const
    {
        if (mCharset->state & MY_CS_NOPAD)
          return str < end;
        return str + mCharset->scan(str, end, MY_SEQ_SPACES) < end;

    }
    bool like(bool neg,
              const utils::ConstString &subject,
              const utils::ConstString &pattern) const
    {
      bool res= !mCharset->wildcmp(subject.str(), subject.end(),
                                   pattern.str(), pattern.end(),
                                   '\\','_','%');
      return neg ? !res : res;
    }
};


class CollationAwareHasher: public Charset
{
public:
    CollationAwareHasher(const Charset &cs)
        :Charset(cs)
    { }
    inline uint32_t operator()(const std::string& s) const
    {
        return operator()(s.data(), s.length());
    }
    inline uint32_t operator()(const char* data, uint64_t len) const
    {
        return Charset::hash(data, len);
    }
};


class CollationAwareComparator: public Charset
{
public:
    CollationAwareComparator(const Charset &cs)
       :Charset(cs)
    { }
    bool operator()(const std::string & str1, const std::string & str2) const
    {
        return Charset::eq(str1, str2);
    }
};


} // end of namespace datatypes

#endif