mariadb/strings/int2str.c

/* Copyright (c) 2000 TXT DataKonsult Ab & Monty Program Ab
   Copyright (c) 2009-2011, Monty Program Ab

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are
   met:

   1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.

   2. Redistributions in binary form must the following disclaimer in
     the documentation and/or other materials provided with the
     distribution.

   THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ``AS IS'' AND ANY
   EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> OR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   SUCH DAMAGE.
*/

#include "strings_def.h"

/*
  _dig_vec arrays are public because they are used in several outer places.
*/
const char _dig_vec_upper[] =
  "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const char _dig_vec_lower[] =
  "0123456789abcdefghijklmnopqrstuvwxyz";


/*
  Convert integer to its string representation in given scale of notation.
   
  SYNOPSIS
    int2str()
      val     - value to convert
      dst     - points to buffer where string representation should be stored
      radix   - radix of scale of notation
      upcase  - set to 1 if we should use upper-case digits

  DESCRIPTION
    Converts the (long) integer value to its character form and moves it to 
    the destination buffer followed by a terminating NUL. 
    If radix is -2..-36, val is taken to be SIGNED, if radix is  2..36, val is
    taken to be UNSIGNED. That is, val is signed if and only if radix is. 
    All other radixes treated as bad and nothing will be changed in this case.

    For conversion to decimal representation (radix is -10 or 10) one can use
    optimized int10_to_str() function.

  RETURN VALUE
    Pointer to ending NUL character or NullS if radix is bad.
*/
  
char *
int2str(register long int val, register char *dst, register int radix, 
        int upcase)
{
  char buffer[65];
  register char *p;
  long int new_val;
  const char *dig_vec= upcase ? _dig_vec_upper : _dig_vec_lower;
  ulong uval= (ulong) val;

  if (radix < 0)
  {
    if (radix < -36 || radix > -2)
      return NullS;
    if (val < 0)
    {
      *dst++ = '-';
      /* Avoid integer overflow in (-val) for LONGLONG_MIN (BUG#31799). */
      uval = (ulong)0 - uval;
    }
    radix = -radix;
  }
  else if (radix > 36 || radix < 2)
    return NullS;

  /*
    The slightly contorted code which follows is due to the fact that
    few machines directly support unsigned long / and %.  Certainly
    the VAX C compiler generates a subroutine call.  In the interests
    of efficiency (hollow laugh) I let this happen for the first digit
    only; after that "val" will be in range so that signed integer
    division will do.  Sorry 'bout that.  CHECK THE CODE PRODUCED BY
    YOUR C COMPILER.  The first % and / should be unsigned, the second
    % and / signed, but C compilers tend to be extraordinarily
    sensitive to minor details of style.  This works on a VAX, that's
    all I claim for it.
  */
  p = &buffer[sizeof(buffer)-1];
  *p = '\0';
  new_val= uval / (ulong) radix;
  *--p = dig_vec[(uchar) (uval- (ulong) new_val*(ulong) radix)];
  val = new_val;
#ifdef HAVE_LDIV
  while (val != 0)
  {
    ldiv_t res;
    res=ldiv(val,radix);
    *--p = dig_vec[res.rem];
    val= res.quot;
  }
#else
  while (val != 0)
  {
    new_val=val/radix;
    *--p = dig_vec[(uchar) (val-new_val*radix)];
    val= new_val;
  }
#endif
  while ((*dst++ = *p++) != 0) ;
  return dst-1;
}


/*
  Converts integer to its string representation in decimal notation.
   
  SYNOPSIS
    int10_to_str()
      val     - value to convert
      dst     - points to buffer where string representation should be stored
      radix   - flag that shows whenever val should be taken as signed or not

  DESCRIPTION
    This is version of int2str() function which is optimized for normal case
    of radix 10/-10. It takes only sign of radix parameter into account and 
    not its absolute value.

  RETURN VALUE
    Pointer to ending NUL character.
*/

char *int10_to_str(long int val,char *dst,int radix)
{
  char buffer[65];
  register char *p;
  long int new_val;
  unsigned long int uval = (unsigned long int) val;

  if (radix < 0)				/* -10 */
  {
    if (val < 0)
    {
      *dst++ = '-';
      /* Avoid integer overflow in (-val) for LONGLONG_MIN (BUG#31799). */
      uval = (unsigned long int)0 - uval;
    }
  }

  p = &buffer[sizeof(buffer)-1];
  *p = '\0';
  new_val= (long) (uval / 10);
  *--p = '0'+ (char) (uval - (unsigned long) new_val * 10);
  val = new_val;

  while (val != 0)
  {
    new_val=val/10;
    *--p = '0' + (char) (val-new_val*10);
    val= new_val;
  }
  while ((*dst++ = *p++) != 0) ;
  return dst-1;
}