release/src/router/mysql/strings/int2str.c

   1 /* Copyright (c) 2000, 2001, 2004, 2007 MySQL AB
   2    Use is subject to license terms.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; version 2 of the License.
   7
   8    This program is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11    GNU General Public License for more details.
  12
  13    You should have received a copy of the GNU General Public License
  14    along with this program; if not, write to the Free Software
  15    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
  16 */
  17
  18 #include <my_global.h>
  19 #include "m_string.h"
  20
  21 /*
  22   _dig_vec arrays are public because they are used in several outer places.
  23 */
  24 char NEAR _dig_vec_upper[] =
  25   "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  26 char NEAR _dig_vec_lower[] =
  27   "0123456789abcdefghijklmnopqrstuvwxyz";
  28
  29
  30 /*
  31   Convert integer to its string representation in given scale of notation.
  32
  33   SYNOPSIS
  34     int2str()
  35       val     - value to convert
  36       dst     - points to buffer where string representation should be stored
  37       radix   - radix of scale of notation
  38       upcase  - set to 1 if we should use upper-case digits
  39
  40   DESCRIPTION
  41     Converts the (long) integer value to its character form and moves it to
  42     the destination buffer followed by a terminating NUL.
  43     If radix is -2..-36, val is taken to be SIGNED, if radix is  2..36, val is
  44     taken to be UNSIGNED. That is, val is signed if and only if radix is.
  45     All other radixes treated as bad and nothing will be changed in this case.
  46
  47     For conversion to decimal representation (radix is -10 or 10) one can use
  48     optimized int10_to_str() function.
  49
  50   RETURN VALUE
  51     Pointer to ending NUL character or NullS if radix is bad.
  52 */
  53
  54 char *
  55 int2str(register long int val, register char *dst, register int radix,
  56         int upcase)
  57 {
  58   char buffer[65];
  59   register char *p;
  60   long int new_val;
  61   char *dig_vec= upcase ? _dig_vec_upper : _dig_vec_lower;
  62   ulong uval= (ulong) val;
  63
  64   if (radix < 0)
  65   {
  66     if (radix < -36 || radix > -2)
  67       return NullS;
  68     if (val < 0)
  69     {
  70       *dst++ = '-';
  71       /* Avoid integer overflow in (-val) for LONGLONG_MIN (BUG#31799). */
  72       uval = (ulong)0 - uval;
  73     }
  74     radix = -radix;
  75   }
  76   else if (radix > 36 || radix < 2)
  77     return NullS;
  78
  79   /*
  80     The slightly contorted code which follows is due to the fact that
  81     few machines directly support unsigned long / and %.  Certainly
  82     the VAX C compiler generates a subroutine call.  In the interests
  83     of efficiency (hollow laugh) I let this happen for the first digit
  84     only; after that "val" will be in range so that signed integer
  85     division will do.  Sorry 'bout that.  CHECK THE CODE PRODUCED BY
  86     YOUR C COMPILER.  The first % and / should be unsigned, the second
  87     % and / signed, but C compilers tend to be extraordinarily
  88     sensitive to minor details of style.  This works on a VAX, that's
  89     all I claim for it.
  90   */
  91   p = &buffer[sizeof(buffer)-1];
  92   *p = '\0';
  93   new_val= uval / (ulong) radix;
  94   *--p = dig_vec[(uchar) (uval- (ulong) new_val*(ulong) radix)];
  95   val = new_val;
  96 #ifdef HAVE_LDIV
  97   while (val != 0)
  98   {
  99     ldiv_t res;
 100     res=ldiv(val,radix);
 101     *--p = dig_vec[res.rem];
 102     val= res.quot;
 103   }
 104 #else
 105   while (val != 0)
 106   {
 107     new_val=val/radix;
 108     *--p = dig_vec[(uchar) (val-new_val*radix)];
 109     val= new_val;
 110   }
 111 #endif
 112   while ((*dst++ = *p++) != 0) ;
 113   return dst-1;
 114 }
 115
 116
 117 /*
 118   Converts integer to its string representation in decimal notation.
 119
 120   SYNOPSIS
 121     int10_to_str()
 122       val     - value to convert
 123       dst     - points to buffer where string representation should be stored
 124       radix   - flag that shows whenever val should be taken as signed or not
 125
 126   DESCRIPTION
 127     This is version of int2str() function which is optimized for normal case
 128     of radix 10/-10. It takes only sign of radix parameter into account and
 129     not its absolute value.
 130
 131   RETURN VALUE
 132     Pointer to ending NUL character.
 133 */
 134
 135 char *int10_to_str(long int val,char *dst,int radix)
 136 {
 137   char buffer[65];
 138   register char *p;
 139   long int new_val;
 140   unsigned long int uval = (unsigned long int) val;
 141
 142   if (radix < 0)                                /* -10 */
 143   {
 144     if (val < 0)
 145     {
 146       *dst++ = '-';
 147       /* Avoid integer overflow in (-val) for LONGLONG_MIN (BUG#31799). */
 148       uval = (unsigned long int)0 - uval;
 149     }
 150   }
 151
 152   p = &buffer[sizeof(buffer)-1];
 153   *p = '\0';
 154   new_val= (long) (uval / 10);
 155   *--p = '0'+ (char) (uval - (unsigned long) new_val * 10);
 156   val = new_val;
 157
 158   while (val != 0)
 159   {
 160     new_val=val/10;
 161     *--p = '0' + (char) (val-new_val*10);
 162     val= new_val;
 163   }
 164   while ((*dst++ = *p++) != 0) ;
 165   return dst-1;
 166 }