int2str.c

MySQL的ODBC接口程序源代码

/*
  Defines: int2str(), itoa(), ltoa()

  int2str(dst, radix, val)
  converts the (long) integer "val" to character form and moves it to
  the destination string "dst" followed by a terminating NUL.  The
  result is normally a pointer to this NUL character, but if the radix
  is dud the result will be NullS and nothing will be changed.

  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.  You will normally
  use radix -10 only through itoa and ltoa, for radix 2, 8, or 16
  unsigned is what you generally want.

  _dig_vec is public just in case someone has a use for it.
  The definitions of itoa and ltoa are actually macros in m_string.h,
  but this is where the code is.

  Note: The standard itoa() returns a pointer to the argument, when int2str
	returns the pointer to the end-null.
	itoa assumes that 10 -base numbers are allways signed and other arn't.
*/

#include <global.h>
#include "m_string.h"

char NEAR _dig_vec[] =
  "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";


char *int2str(val,dst, radix)
    register long val;
    register char *dst;
    register int radix;
{
  char buffer[33];
  register char *p;

  if (radix < 0) {
    if (radix < -36 || radix > -2) return NullS;
    if (val < 0) {
      *dst++ = '-';
      val = -val;
    }
    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[32];
  *p = '\0';
  *--p = _dig_vec[(ulong) val % (ulong) radix];
  val = (ulong) val / (ulong) radix;
#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)
  {
    *--p = _dig_vec[val%radix];
    val /= radix;
  }
#endif
  while ((*dst++ = *p++) != 0) ;
  return dst-1;
}

#if defined(HAVE_LONG_LONG) && !defined(longlong2str)

char *longlong2str(val,dst, radix)
    register longlong val;
    register char *dst;
    register int radix;
{
  char buffer[64];
  register char *p;

  if (radix < 0) {
    if (radix < -36 || radix > -2) return NullS;
    if (val < 0) {
      *dst++ = '-';
      val = -val;
    }
    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';
  *--p = _dig_vec[(ulonglong) val % (ulonglong) radix];
  val = (ulonglong) val / (ulonglong) radix;

  while (val != 0)
  {
    *--p = _dig_vec[val%radix];
    val /= radix;
  }
  while ((*dst++ = *p++) != 0) ;
  return dst-1;
}
#endif

#ifdef USE_MY_ITOA

	/* Change to less general itoa interface */

char *my_itoa(val,dst,radix)
int val;
char *dst;
int radix;
{
  VOID(int2str((long) val,dst,(radix == 10 ? -10 : radix)));
  return dst;
}

char *my_ltoa(val,dst,radix)
long val;
char *dst;
int radix;
{
  VOID(int2str((long) val,dst,(radix == 10 ? -10 : radix)));
  return dst;
}

#endif