ref: c11957a7915d355d80ff7e6a21721ba05441ca29
dir: /libmath/g_fmt.c/
/**************************************************************** * * The author of this software is David M. Gay. * * Copyright (c) 1991, 1996 by Lucent Technologies. * * Permission to use, copy, modify, and distribute this software for any * purpose without fee is hereby granted, provided that this entire notice * is included in all copies of any software which is or includes a copy * or modification of this software and in all copies of the supporting * documentation for such software. * * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED * WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR LUCENT MAKES ANY * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. * ***************************************************************/ /* g_fmt(buf,x) stores the closest decimal approximation to x in buf; * it suffices to declare buf * char buf[32]; */ #ifdef __cplusplus extern "C" { #endif extern char *dtoa(double, int, int, int *, int *, char **); extern char *g_fmt(char *, double, int); extern void freedtoa(char*); #ifdef __cplusplus } #endif char * g_fmt(register char *b, double x, int echr) { register int i, k; register char *s; int decpt, j, sign; char *b0, *s0, *se; b0 = b; #ifdef IGNORE_ZERO_SIGN if (!x) { *b++ = '0'; *b = 0; goto done; } #endif s = s0 = dtoa(x, 0, 0, &decpt, &sign, &se); if (sign) *b++ = '-'; if (decpt == 9999) /* Infinity or Nan */ { while(*b++ = *s++); goto done0; } if (decpt <= -4 || decpt > se - s + 5) { *b++ = *s++; if (*s) { *b++ = '.'; while(*b = *s++) b++; } *b++ = echr; /* sprintf(b, "%+.2d", decpt - 1); */ if (--decpt < 0) { *b++ = '-'; decpt = -decpt; } else *b++ = '+'; for(j = 2, k = 10; 10*k <= decpt; j++, k *= 10); for(;;) { i = decpt / k; *b++ = i + '0'; if (--j <= 0) break; decpt -= i*k; decpt *= 10; } *b = 0; } else if (decpt <= 0) { *b++ = '.'; for(; decpt < 0; decpt++) *b++ = '0'; while(*b++ = *s++); } else { while(*b = *s++) { b++; if (--decpt == 0 && *s) *b++ = '.'; } for(; decpt > 0; decpt--) *b++ = '0'; *b = 0; } done0: freedtoa(s0); #ifdef IGNORE_ZERO_SIGN done: #endif return b0; }