int2str.c
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上传日期:2022-05-23
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文件大小:5k
- /* Copyright (C) 2000 MySQL AB
- 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; either version 2 of the License, or
- (at your option) any later version.
- 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
- #include <my_global.h>
- #include "m_string.h"
- /*
- _dig_vec arrays are public because they are used in several outer places.
- */
- char NEAR _dig_vec_upper[] =
- "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
- char NEAR _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;
- char *dig_vec= upcase ? _dig_vec_upper : _dig_vec_lower;
- 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 = ' ';
- new_val=(ulong) val / (ulong) radix;
- *--p = dig_vec[(uchar) ((ulong) val- (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;
- if (radix < 0) /* -10 */
- {
- if (val < 0)
- {
- *dst++ = '-';
- val = -val;
- }
- }
- p = &buffer[sizeof(buffer)-1];
- *p = ' ';
- new_val= (long) ((unsigned long int) val / 10);
- *--p = '0'+ (char) ((unsigned long int) val - (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;
- }