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[/] [wdsp/] [trunk/] [sw/] [IIR6/] [int2str.c] - Rev 10
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#include "../support/support.h" #include "../support/board.h" #include "../support/uart.h" #include "../support/spr_defs.h" /* 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 _dig_vec[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; char *int2str(register long int val, register char *dst, register int radix) { char buffer[65]; register char *p; long int new_val; if (radix < 0) { if (radix < -36 || radix > -2) return NULL; if (val < 0) { *dst++ = '-'; val = -val; } radix = -radix; } else { if (radix > 36 || radix < 2) return NULL; } /* 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=(unsigned long) val / (unsigned long) radix; *--p = _dig_vec[(unsigned char) ((unsigned long) val- (unsigned long) new_val*(unsigned long) 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[(unsigned char) (val-new_val*radix)]; val= new_val; } #endif while ((*dst++ = *p++) != 0) ; return dst-1; } /* This is a faster version of the above optimized for the normal case of radix 10 / -10 */ 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 = '\0'; 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; }
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