sql_string.cc

/*
   Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

   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
*/

/* This file is originally from the mysql distribution. Coded by monty */

#include <my_global.h>
#include <my_sys.h>
#include <m_string.h>
#include <m_ctype.h>
#include <mysql_com.h>

#include "sql_string.h"

#include <algorithm>

using std::min;
using std::max;

/*****************************************************************************
** String functions
*****************************************************************************/

bool String::real_alloc(uint32 length)
{
  uint32 arg_length= ALIGN_SIZE(length + 1);
  DBUG_ASSERT(arg_length > length);
  if (arg_length <= length)
    return TRUE;                                 /* Overflow */
  str_length=0;
  if (Alloced_length < arg_length)
  {
    free();
    if (!(Ptr=(char*) my_malloc(arg_length,MYF(MY_WME))))
      return TRUE;
    Alloced_length=arg_length;
    alloced=1;
  }
  Ptr[0]=0;
  return FALSE;
}


/*
** Check that string is big enough. Set string[alloc_length] to 0
** (for C functions)
*/

bool String::realloc(uint32 alloc_length)
{
  uint32 len=ALIGN_SIZE(alloc_length+1);
  DBUG_ASSERT(len > alloc_length);
  if (len <= alloc_length)
    return TRUE;                                 /* Overflow */
  if (Alloced_length < len)
  {
    char *new_ptr;
    if (alloced)
    {
      if (!(new_ptr= (char*) my_realloc(Ptr,len,MYF(MY_WME))))
        return TRUE;                            // Signal error
    }
    else if ((new_ptr= (char*) my_malloc(len,MYF(MY_WME))))
    {
      if (str_length > len - 1)
        str_length= 0;
      if (str_length)                           // Avoid bugs in memcpy on AIX
        memcpy(new_ptr,Ptr,str_length);
      new_ptr[str_length]=0;
      alloced=1;
    }
    else
      return TRUE;                      // Signal error
    Ptr= new_ptr;
    Alloced_length= len;
  }
  Ptr[alloc_length]=0;                  // This make other funcs shorter
  return FALSE;
}

bool String::set(longlong num, const CHARSET_INFO *cs)
{
  uint l=20*cs->mbmaxlen+1;

  if (alloc(l))
    return TRUE;
  str_length=(uint32) (cs->cset->longlong10_to_str)(cs,Ptr,l,-10,num);
  str_charset=cs;
  return FALSE;
}

bool String::set(ulonglong num, const CHARSET_INFO *cs)
{
  uint l=20*cs->mbmaxlen+1;

  if (alloc(l))
    return TRUE;
  str_length=(uint32) (cs->cset->longlong10_to_str)(cs,Ptr,l,10,num);
  str_charset=cs;
  return FALSE;
}

bool String::set(double num,uint decimals, const CHARSET_INFO *cs)
{
  char buff[FLOATING_POINT_BUFFER];
  uint dummy_errors;
  size_t len;

  str_charset=cs;
  if (decimals >= NOT_FIXED_DEC)
  {
    len= my_gcvt(num, MY_GCVT_ARG_DOUBLE, sizeof(buff) - 1, buff, NULL);
    return copy(buff, len, &my_charset_latin1, cs, &dummy_errors);
  }
  len= my_fcvt(num, decimals, buff, NULL);
  return copy(buff, (uint32) len, &my_charset_latin1, cs,
              &dummy_errors);
}


bool String::copy()
{
  if (!alloced)
  {
    Alloced_length=0;                           // Force realloc
    return realloc(str_length);
  }
  return FALSE;
}

bool String::copy(const String &str)
{
  if (alloc(str.str_length))
    return TRUE;
  str_length=str.str_length;
  bmove(Ptr,str.Ptr,str_length);                // May be overlapping
  Ptr[str_length]=0;
  str_charset=str.str_charset;
  return FALSE;
}

bool String::copy(const char *str,uint32 arg_length, const CHARSET_INFO *cs)
{
  if (alloc(arg_length))
    return TRUE;
  if ((str_length=arg_length))
    memcpy(Ptr,str,arg_length);
  Ptr[arg_length]=0;
  str_charset=cs;
  return FALSE;
}


/*
  Checks that the source string can be just copied to the destination string
  without conversion.

  SYNPOSIS

  needs_conversion()
  arg_length            Length of string to copy.
  from_cs               Character set to copy from
  to_cs                 Character set to copy to
  uint32 *offset        Returns number of unaligned characters.

  RETURN
   0  No conversion needed
   1  Either character set conversion or adding leading  zeros
      (e.g. for UCS-2) must be done

  NOTE
  to_cs may be NULL for "no conversion" if the system variable
  character_set_results is NULL.
*/

bool String::needs_conversion(uint32 arg_length,
                              const CHARSET_INFO *from_cs,
                              const CHARSET_INFO *to_cs,
                              uint32 *offset)
{
  *offset= 0;
  if (!to_cs ||
      (to_cs == &my_charset_bin) || 
      (to_cs == from_cs) ||
      my_charset_same(from_cs, to_cs) ||
      ((from_cs == &my_charset_bin) &&
       (!(*offset=(arg_length % to_cs->mbminlen)))))
    return FALSE;
  return TRUE;
}


/*
  Copy a multi-byte character sets with adding leading zeros.

  SYNOPSIS

  copy_aligned()
  str                   String to copy
  arg_length            Length of string. This should NOT be dividable with
                        cs->mbminlen.
  offset                arg_length % cs->mb_minlength
  cs                    Character set for 'str'

  NOTES
    For real multi-byte, ascii incompatible charactser sets,
    like UCS-2, add leading zeros if we have an incomplete character.
    Thus, 
      SELECT _ucs2 0xAA 
    will automatically be converted into
      SELECT _ucs2 0x00AA

  RETURN
    0  ok
    1  error
*/

bool String::copy_aligned(const char *str,uint32 arg_length, uint32 offset,
                          const CHARSET_INFO *cs)
{
  /* How many bytes are in incomplete character */
  offset= cs->mbmaxlen - offset; /* How many zeros we should prepend */
  DBUG_ASSERT(offset && offset != cs->mbmaxlen);

  uint32 aligned_length= arg_length + offset;
  if (alloc(aligned_length))
    return TRUE;
  
  /*
    Note, this is only safe for little-endian UCS-2.
    If we add big-endian UCS-2 sometimes, this code
    will be more complicated. But it's OK for now.
  */
  memset(Ptr, 0, offset);
  memcpy(Ptr + offset, str, arg_length);
  Ptr[aligned_length]=0;
  /* str_length is always >= 0 as arg_length is != 0 */
  str_length= aligned_length;
  str_charset= cs;
  return FALSE;
}


bool String::set_or_copy_aligned(const char *str,uint32 arg_length,
                                 const CHARSET_INFO *cs)
{
  /* How many bytes are in incomplete character */
  uint32 offset= (arg_length % cs->mbminlen); 
  
  if (!offset) /* All characters are complete, just copy */
  {
    set(str, arg_length, cs);
    return FALSE;
  }
  return copy_aligned(str, arg_length, offset, cs);
}

        /* Copy with charset convertion */

bool String::copy(const char *str, uint32 arg_length,
                  const CHARSET_INFO *from_cs, const CHARSET_INFO *to_cs, uint *errors)
{
  uint32 offset;
  if (!needs_conversion(arg_length, from_cs, to_cs, &offset))
  {
    *errors= 0;
    return copy(str, arg_length, to_cs);
  }
  if ((from_cs == &my_charset_bin) && offset)
  {
    *errors= 0;
    return copy_aligned(str, arg_length, offset, to_cs);
  }
  uint32 new_length= to_cs->mbmaxlen*arg_length;
  if (alloc(new_length))
    return TRUE;
  str_length=copy_and_convert((char*) Ptr, new_length, to_cs,
                              str, arg_length, from_cs, errors);
  str_charset=to_cs;
  return FALSE;
}


/*
  Set a string to the value of a latin1-string, keeping the original charset
  
  SYNOPSIS
    copy_or_set()
    str                 String of a simple charset (latin1)
    arg_length          Length of string

  IMPLEMENTATION
    If string object is of a simple character set, set it to point to the
    given string.
    If not, make a copy and convert it to the new character set.

  RETURN
    0   ok
    1   Could not allocate result buffer

*/

bool String::set_ascii(const char *str, uint32 arg_length)
{
  if (str_charset->mbminlen == 1)
  {
    set(str, arg_length, str_charset);
    return 0;
  }
  uint dummy_errors;
  return copy(str, arg_length, &my_charset_latin1, str_charset, &dummy_errors);
}


/* This is used by mysql.cc */

bool String::fill(uint32 max_length,char fill_char)
{
  if (str_length > max_length)
    Ptr[str_length=max_length]=0;
  else
  {
    if (realloc(max_length))
      return TRUE;
    memset(Ptr+str_length, fill_char, max_length-str_length);
    str_length=max_length;
  }
  return FALSE;
}

void String::strip_sp()
{
   while (str_length && my_isspace(str_charset,Ptr[str_length-1]))
    str_length--;
}

bool String::append(const String &s)
{
  if (s.length())
  {
    if (realloc(str_length+s.length()))
      return TRUE;
    memcpy(Ptr+str_length,s.ptr(),s.length());
    str_length+=s.length();
  }
  return FALSE;
}


/*
  Append an ASCII string to the a string of the current character set
*/

bool String::append(const char *s,uint32 arg_length)
{
  if (!arg_length)
    return FALSE;

  /*
    For an ASCII incompatible string, e.g. UCS-2, we need to convert
  */
  if (str_charset->mbminlen > 1)
  {
    uint32 add_length=arg_length * str_charset->mbmaxlen;
    uint dummy_errors;
    if (realloc(str_length+ add_length))
      return TRUE;
    str_length+= copy_and_convert(Ptr+str_length, add_length, str_charset,
                                  s, arg_length, &my_charset_latin1,
                                  &dummy_errors);
    return FALSE;
  }

  /*
    For an ASCII compatinble string we can just append.
  */
  if (realloc(str_length+arg_length))
    return TRUE;
  memcpy(Ptr+str_length,s,arg_length);
  str_length+=arg_length;
  return FALSE;
}


/*
  Append a 0-terminated ASCII string
*/

bool String::append(const char *s)
{
  return append(s, (uint) strlen(s));
}


/*
  Append a string in the given charset to the string
  with character set recoding
*/

bool String::append(const char *s,uint32 arg_length, const CHARSET_INFO *cs)
{
  uint32 dummy_offset;
  
  if (needs_conversion(arg_length, cs, str_charset, &dummy_offset))
  {
    uint32 add_length= arg_length / cs->mbminlen * str_charset->mbmaxlen;
    uint dummy_errors;
    if (realloc(str_length + add_length)) 
      return TRUE;
    str_length+= copy_and_convert(Ptr+str_length, add_length, str_charset,
                                  s, arg_length, cs, &dummy_errors);
  }
  else
  {
    if (realloc(str_length + arg_length)) 
      return TRUE;
    memcpy(Ptr + str_length, s, arg_length);
    str_length+= arg_length;
  }
  return FALSE;
}


#ifdef TO_BE_REMOVED
bool String::append(FILE* file, uint32 arg_length, myf my_flags)
{
  if (realloc(str_length+arg_length))
    return TRUE;
  if (my_fread(file, (uchar*) Ptr + str_length, arg_length, my_flags))
  {
    shrink(str_length);
    return TRUE;
  }
  str_length+=arg_length;
  return FALSE;
}
#endif

bool String::append(IO_CACHE* file, uint32 arg_length)
{
  if (realloc(str_length+arg_length))
    return TRUE;
  if (my_b_read(file, (uchar*) Ptr + str_length, arg_length))
  {
    shrink(str_length);
    return TRUE;
  }
  str_length+=arg_length;
  return FALSE;
}

bool String::append_with_prefill(const char *s,uint32 arg_length,
                 uint32 full_length, char fill_char)
{
  int t_length= arg_length > full_length ? arg_length : full_length;

  if (realloc(str_length + t_length))
    return TRUE;
  t_length= full_length - arg_length;
  if (t_length > 0)
  {
    memset(Ptr+str_length, fill_char, t_length);
    str_length=str_length + t_length;
  }
  append(s, arg_length);
  return FALSE;
}

uint32 String::numchars() const
{
  return str_charset->cset->numchars(str_charset, Ptr, Ptr+str_length);
}

int String::charpos(int i,uint32 offset)
{
  if (i <= 0)
    return i;
  return str_charset->cset->charpos(str_charset,Ptr+offset,Ptr+str_length,i);
}

int String::strstr(const String &s,uint32 offset)
{
  if (s.length()+offset <= str_length)
  {
    if (!s.length())
      return ((int) offset);    // Empty string is always found

    register const char *str = Ptr+offset;
    register const char *search=s.ptr();
    const char *end=Ptr+str_length-s.length()+1;
    const char *search_end=s.ptr()+s.length();
skip:
    while (str != end)
    {
      if (*str++ == *search)
      {
        register char *i,*j;
        i=(char*) str; j=(char*) search+1;
        while (j != search_end)
          if (*i++ != *j++) goto skip;
        return (int) (str-Ptr) -1;
      }
    }
  }
  return -1;
}

/*
** Search string from end. Offset is offset to the end of string
*/

int String::strrstr(const String &s,uint32 offset)
{
  if (s.length() <= offset && offset <= str_length)
  {
    if (!s.length())
      return offset;                            // Empty string is always found
    register const char *str = Ptr+offset-1;
    register const char *search=s.ptr()+s.length()-1;

    const char *end=Ptr+s.length()-2;
    const char *search_end=s.ptr()-1;
skip:
    while (str != end)
    {
      if (*str-- == *search)
      {
        register char *i,*j;
        i=(char*) str; j=(char*) search-1;
        while (j != search_end)
          if (*i-- != *j--) goto skip;
        return (int) (i-Ptr) +1;
      }
    }
  }
  return -1;
}

/*
  Replace substring with string
  If wrong parameter or not enough memory, do nothing
*/

bool String::replace(uint32 offset,uint32 arg_length,const String &to)
{
  return replace(offset,arg_length,to.ptr(),to.length());
}

bool String::replace(uint32 offset,uint32 arg_length,
                     const char *to, uint32 to_length)
{
  long diff = (long) to_length-(long) arg_length;
  if (offset+arg_length <= str_length)
  {
    if (diff < 0)
    {
      if (to_length)
        memcpy(Ptr+offset,to,to_length);
      bmove(Ptr+offset+to_length,Ptr+offset+arg_length,
            str_length-offset-arg_length);
    }
    else
    {
      if (diff)
      {
        if (realloc(str_length+(uint32) diff))
          return TRUE;
        bmove_upp((uchar*) Ptr+str_length+diff, (uchar*) Ptr+str_length,
                  str_length-offset-arg_length);
      }
      if (to_length)
        memcpy(Ptr+offset,to,to_length);
    }
    str_length+=(uint32) diff;
  }
  return FALSE;
}


// added by Holyfoot for "geometry" needs
int String::reserve(uint32 space_needed, uint32 grow_by)
{
  if (Alloced_length < str_length + space_needed)
  {
    if (realloc(Alloced_length + max(space_needed, grow_by) - 1))
      return TRUE;
  }
  return FALSE;
}

void String::qs_append(const char *str, uint32 len)
{
  memcpy(Ptr + str_length, str, len + 1);
  str_length += len;
}

void String::qs_append(double d)
{
  char *buff = Ptr + str_length;
  str_length+= my_gcvt(d, MY_GCVT_ARG_DOUBLE, FLOATING_POINT_BUFFER - 1, buff,
                       NULL);
}

void String::qs_append(double *d)
{
  double ld;
  float8get(ld, (char*) d);
  qs_append(ld);
}

void String::qs_append(int i)
{
  char *buff= Ptr + str_length;
  char *end= int10_to_str(i, buff, -10);
  str_length+= (int) (end-buff);
}

void String::qs_append(uint i)
{
  char *buff= Ptr + str_length;
  char *end= int10_to_str(i, buff, 10);
  str_length+= (int) (end-buff);
}

/*
  Compare strings according to collation, without end space.

  SYNOPSIS
    sortcmp()
    s           First string
    t           Second string
    cs          Collation

  NOTE:
    Normally this is case sensitive comparison

  RETURN
  < 0   s < t
  0     s == t
  > 0   s > t
*/


int sortcmp(const String *s,const String *t, const CHARSET_INFO *cs)
{
 return cs->coll->strnncollsp(cs,
                              (unsigned char *) s->ptr(),s->length(),
                              (unsigned char *) t->ptr(),t->length(), 0);
}


/*
  Compare strings byte by byte. End spaces are also compared.

  SYNOPSIS
    stringcmp()
    s           First string
    t           Second string

  NOTE:
    Strings are compared as a stream of unsigned chars

  RETURN
  < 0   s < t
  0     s == t
  > 0   s > t
*/


int stringcmp(const String *s,const String *t)
{
  uint32 s_len=s->length(),t_len=t->length(),len=min(s_len,t_len);
  int cmp= memcmp(s->ptr(), t->ptr(), len);
  return (cmp) ? cmp : (int) (s_len - t_len);
}


String *copy_if_not_alloced(String *to,String *from,uint32 from_length)
{
  if (from->Alloced_length >= from_length)
    return from;
  if ((from->alloced && (from->Alloced_length != 0)) || !to || from == to)
  {
    (void) from->realloc(from_length);
    return from;
  }
  if (to->realloc(from_length))
    return from;                                // Actually an error
  if ((to->str_length=min(from->str_length,from_length)))
    memcpy(to->Ptr,from->Ptr,to->str_length);
  to->str_charset=from->str_charset;
  return to;
}


/****************************************************************************
  Help functions
****************************************************************************/

void String::print(String *str)
{
  char *st= (char*)Ptr, *end= st+str_length;
  for (; st < end; st++)
  {
    uchar c= *st;
    switch (c)
    {
    case '\\':
      str->append(STRING_WITH_LEN("\\\\"));
      break;
    case '\0':
      str->append(STRING_WITH_LEN("\\0"));
      break;
    case '\'':
      str->append(STRING_WITH_LEN("\\'"));
      break;
    case '\n':
      str->append(STRING_WITH_LEN("\\n"));
      break;
    case '\r':
      str->append(STRING_WITH_LEN("\\r"));
      break;
    case 26: //Ctrl-Z
      str->append(STRING_WITH_LEN("\\z"));
      break;
    default:
      str->append(c);
    }
  }
}


/*
  Exchange state of this object and argument.

  SYNOPSIS
    String::swap()

  RETURN
    Target string will contain state of this object and vice versa.
*/

void String::swap(String &s)
{
  swap_variables(char *, Ptr, s.Ptr);
  swap_variables(uint32, str_length, s.str_length);
  swap_variables(uint32, Alloced_length, s.Alloced_length);
  swap_variables(bool, alloced, s.alloced);
  swap_variables(const CHARSET_INFO*, str_charset, s.str_charset);
}