sql_string.h

#ifndef CLIENT_SQL_STRING_INCLUDED
#define CLIENT_SQL_STRING_INCLUDED

/* 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 "m_ctype.h"
#include "my_sys.h"

class String;
int sortcmp(const String *a,const String *b, const CHARSET_INFO *cs);
String *copy_if_not_alloced(String *a,String *b,uint32 arg_length);
inline uint32 copy_and_convert(char *to, uint32 to_length,
                               const CHARSET_INFO *to_cs,
                               const char *from, uint32 from_length,
                               const CHARSET_INFO *from_cs, uint *errors)
{
  return my_convert(to, to_length, to_cs, from, from_length, from_cs, errors);
}

class String
{
  char *Ptr;
  uint32 str_length,Alloced_length;
  bool alloced;
  const CHARSET_INFO *str_charset;
public:
  String()
  { 
    Ptr=0; str_length=Alloced_length=0; alloced=0; 
    str_charset= &my_charset_bin; 
  }
  String(uint32 length_arg)
  { 
    alloced=0; Alloced_length=0; (void) real_alloc(length_arg); 
    str_charset= &my_charset_bin;
  }
  String(const char *str, const CHARSET_INFO *cs)
  { 
    Ptr=(char*) str; str_length=(uint) strlen(str); Alloced_length=0; alloced=0;
    str_charset=cs;
  }
  String(const char *str,uint32 len, const CHARSET_INFO *cs)
  { 
    Ptr=(char*) str; str_length=len; Alloced_length=0; alloced=0;
    str_charset=cs;
  }
  String(char *str,uint32 len, const CHARSET_INFO *cs)
  { 
    Ptr=(char*) str; Alloced_length=str_length=len; alloced=0;
    str_charset=cs;
  }
  String(const String &str)
  { 
    Ptr=str.Ptr ; str_length=str.str_length ;
    Alloced_length=str.Alloced_length; alloced=0; 
    str_charset=str.str_charset;
  }
  static void *operator new(size_t size, MEM_ROOT *mem_root)
  { return (void*) alloc_root(mem_root, (uint) size); }
  static void operator delete(void *ptr_arg, size_t size)
  {
    (void) ptr_arg;
    (void) size;
    TRASH(ptr_arg, size);
  }
  static void operator delete(void *, MEM_ROOT *)
  { /* never called */ }
  ~String() { free(); }

  inline void set_charset(const CHARSET_INFO *charset_arg)
  { str_charset= charset_arg; }
  inline const CHARSET_INFO *charset() const { return str_charset; }
  inline uint32 length() const { return str_length;}
  inline uint32 alloced_length() const { return Alloced_length;}
  inline char& operator [] (uint32 i) const { return Ptr[i]; }
  inline void length(uint32 len) { str_length=len ; }
  inline bool is_empty() { return (str_length == 0); }
  inline void mark_as_const() { Alloced_length= 0;}
  inline const char *ptr() const { return Ptr; }
  inline char *c_ptr()
  {
    DBUG_ASSERT(!alloced || !Ptr || !Alloced_length || 
                (Alloced_length >= (str_length + 1)));

    if (!Ptr || Ptr[str_length])                /* Should be safe */
      (void) realloc(str_length);
    return Ptr;
  }
  inline char *c_ptr_quick()
  {
    if (Ptr && str_length < Alloced_length)
      Ptr[str_length]=0;
    return Ptr;
  }
  inline char *c_ptr_safe()
  {
    if (Ptr && str_length < Alloced_length)
      Ptr[str_length]=0;
    else
      (void) realloc(str_length);
    return Ptr;
  }

  void set(String &str,uint32 offset,uint32 arg_length)
  {
    DBUG_ASSERT(&str != this);
    free();
    Ptr=(char*) str.ptr()+offset; str_length=arg_length; alloced=0;
    if (str.Alloced_length)
      Alloced_length=str.Alloced_length-offset;
    else
      Alloced_length=0;
    str_charset=str.str_charset;
  }
  inline void set(char *str,uint32 arg_length, const CHARSET_INFO *cs)
  {
    free();
    Ptr=(char*) str; str_length=Alloced_length=arg_length ; alloced=0;
    str_charset=cs;
  }
  inline void set(const char *str,uint32 arg_length, const CHARSET_INFO *cs)
  {
    free();
    Ptr=(char*) str; str_length=arg_length; Alloced_length=0 ; alloced=0;
    str_charset=cs;
  }
  bool set_ascii(const char *str, uint32 arg_length);
  inline void set_quick(char *str,uint32 arg_length, const CHARSET_INFO *cs)
  {
    if (!alloced)
    {
      Ptr=(char*) str; str_length=Alloced_length=arg_length;
    }
    str_charset=cs;
  }
  bool set(longlong num, const CHARSET_INFO *cs);
  bool set(ulonglong num, const CHARSET_INFO *cs);
  bool set(double num,uint decimals, const CHARSET_INFO *cs);

  /*
    PMG 2004.11.12
    This is a method that works the same as perl's "chop". It simply
    drops the last character of a string. This is useful in the case
    of the federated storage handler where I'm building a unknown
    number, list of values and fields to be used in a sql insert
    statement to be run on the remote server, and have a comma after each.
    When the list is complete, I "chop" off the trailing comma

    ex. 
      String stringobj; 
      stringobj.append("VALUES ('foo', 'fi', 'fo',");
      stringobj.chop();
      stringobj.append(")");

    In this case, the value of string was:

    VALUES ('foo', 'fi', 'fo',
    VALUES ('foo', 'fi', 'fo'
    VALUES ('foo', 'fi', 'fo')
      
  */
  inline void chop()
  {
    Ptr[str_length--]= '\0'; 
  }

  inline void free()
  {
    if (alloced)
    {
      alloced=0;
      Alloced_length=0;
      my_free(Ptr);
      Ptr=0;
      str_length=0;                             /* Safety */
    }
  }
  inline bool alloc(uint32 arg_length)
  {
    if (arg_length < Alloced_length)
      return 0;
    return real_alloc(arg_length);
  }
  bool real_alloc(uint32 arg_length);                   // Empties old string
  bool realloc(uint32 arg_length);

  // Shrink the buffer, but only if it is allocated on the heap.
  inline void shrink(uint32 arg_length)
  {
    if (!is_alloced())
      return;
    if (arg_length < Alloced_length)
    {
      char *new_ptr;
      if (!(new_ptr=(char*) my_realloc(Ptr,arg_length,MYF(0))))
      {
        Alloced_length = 0;
        real_alloc(arg_length);
      }
      else
      {
        Ptr=new_ptr;
        Alloced_length=arg_length;
      }
    }
  }
  bool is_alloced() const { return alloced; }
  inline String& operator = (const String &s)
  {
    if (&s != this)
    {
      /*
        It is forbidden to do assignments like 
        some_string = substring_of_that_string
       */
      DBUG_ASSERT(!s.uses_buffer_owned_by(this));
      free();
      Ptr=s.Ptr ; str_length=s.str_length ; Alloced_length=s.Alloced_length;
      str_charset=s.str_charset;
      alloced=0;
    }
    return *this;
  }

  bool copy();                                  // Alloc string if not alloced
  bool copy(const String &s);                   // Allocate new string
  bool copy(const char *s,uint32 arg_length, const CHARSET_INFO *cs);
  static bool needs_conversion(uint32 arg_length,
                               const CHARSET_INFO *cs_from, const CHARSET_INFO *cs_to,
                               uint32 *offset);
  bool copy_aligned(const char *s, uint32 arg_length, uint32 offset,
                    const CHARSET_INFO *cs);
  bool set_or_copy_aligned(const char *s, uint32 arg_length,
                           const CHARSET_INFO *cs);
  bool copy(const char*s,uint32 arg_length, const CHARSET_INFO *csfrom,
            const CHARSET_INFO *csto, uint *errors);
  bool append(const String &s);
  bool append(const char *s);
  bool append(const char *s,uint32 arg_length);
  bool append(const char *s,uint32 arg_length, const CHARSET_INFO *cs);
  bool append(IO_CACHE* file, uint32 arg_length);
  bool append_with_prefill(const char *s, uint32 arg_length, 
                           uint32 full_length, char fill_char);
  int strstr(const String &search,uint32 offset=0); // Returns offset to substring or -1
  int strrstr(const String &search,uint32 offset=0); // Returns offset to substring or -1
  bool replace(uint32 offset,uint32 arg_length,const char *to,uint32 length);
  bool replace(uint32 offset,uint32 arg_length,const String &to);
  inline bool append(char chr)
  {
    if (str_length < Alloced_length)
    {
      Ptr[str_length++]=chr;
    }
    else
    {
      if (realloc(str_length+1))
        return 1;
      Ptr[str_length++]=chr;
    }
    return 0;
  }
  bool fill(uint32 max_length,char fill);
  void strip_sp();
  friend int sortcmp(const String *a,const String *b, const CHARSET_INFO *cs);
  friend int stringcmp(const String *a,const String *b);
  friend String *copy_if_not_alloced(String *a,String *b,uint32 arg_length);
  uint32 numchars() const;
  int charpos(int i,uint32 offset=0);

  int reserve(uint32 space_needed)
  {
    return realloc(str_length + space_needed);
  }
  int reserve(uint32 space_needed, uint32 grow_by);

  /*
    The following append operations do NOT check alloced memory
    q_*** methods writes values of parameters itself
    qs_*** methods writes string representation of value
  */
  void q_append(const char c)
  {
    Ptr[str_length++] = c;
  }
  void q_append(const uint32 n)
  {
    int4store(Ptr + str_length, n);
    str_length += 4;
  }
  void q_append(double d)
  {
    float8store(Ptr + str_length, d);
    str_length += 8;
  }
  void q_append(double *d)
  {
    float8store(Ptr + str_length, *d);
    str_length += 8;
  }
  void q_append(const char *data, uint32 data_len)
  {
    memcpy(Ptr + str_length, data, data_len);
    str_length += data_len;
  }

  void write_at_position(int position, uint32 value)
  {
    int4store(Ptr + position,value);
  }

  void qs_append(const char *str, uint32 len);
  void qs_append(double d);
  void qs_append(double *d);
  inline void qs_append(const char c)
  {
     Ptr[str_length]= c;
     str_length++;
  }
  void qs_append(int i);
  void qs_append(uint i);

  /* Inline (general) functions used by the protocol functions */

  inline char *prep_append(uint32 arg_length, uint32 step_alloc)
  {
    uint32 new_length= arg_length + str_length;
    if (new_length > Alloced_length)
    {
      if (realloc(new_length + step_alloc))
        return 0;
    }
    uint32 old_length= str_length;
    str_length+= arg_length;
    return Ptr+ old_length;                     /* Area to use */
  }

  inline bool append(const char *s, uint32 arg_length, uint32 step_alloc)
  {
    uint32 new_length= arg_length + str_length;
    if (new_length > Alloced_length && realloc(new_length + step_alloc))
      return TRUE;
    memcpy(Ptr+str_length, s, arg_length);
    str_length+= arg_length;
    return FALSE;
  }
  void print(String *print);

  /* Swap two string objects. Efficient way to exchange data without memcpy. */
  void swap(String &s);

  inline bool uses_buffer_owned_by(const String *s) const
  {
    return (s->alloced && Ptr >= s->Ptr && Ptr < s->Ptr + s->str_length);
  }
};

#endif /* CLIENT_SQL_STRING_INCLUDED */