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1.1 root 1: /*
2: * Copyright (c) 1988 Regents of the University of California.
3: * All rights reserved.
4: *
5: * Redistribution and use in source and binary forms are permitted
6: * provided that the above copyright notice and this paragraph are
7: * duplicated in all such forms and that any documentation,
8: * advertising materials, and other materials related to such
9: * distribution and use acknowledge that the software was developed
10: * by the University of California, Berkeley. The name of the
11: * University may not be used to endorse or promote products derived
12: * from this software without specific prior written permission.
13: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14: * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15: * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16: */
17:
18: #if defined(LIBC_SCCS) && !defined(lint)
19: static char sccsid[] = "@(#)doprnt.c 5.35 (Berkeley) 6/27/88";
20: #endif /* LIBC_SCCS and not lint */
21:
22: #include <sys/types.h>
23: #include <varargs.h>
24: #include <stdio.h>
25: #include <ctype.h>
26:
27: /* 11-bit exponent (VAX G floating point) is 308 decimal digits */
28: #define MAXEXP 308
29: /* 128 bit fraction takes up 39 decimal digits; max reasonable precision */
30: #define MAXFRACT 39
31:
32: #define DEFPREC 6
33:
34: #define BUF (MAXEXP+MAXFRACT+1) /* + decimal point */
35:
36: #define PUTC(ch) (void) putc(ch, fp)
37:
38: #define ARG() \
39: _ulong = flags&LONGINT ? va_arg(argp, long) : \
40: flags&SHORTINT ? va_arg(argp, short) : va_arg(argp, int);
41:
42: #define todigit(c) ((c) - '0')
43: #define tochar(n) ((n) + '0')
44:
45: /* have to deal with the negative buffer count kludge */
46: #define NEGATIVE_COUNT_KLUDGE
47:
48: #define LONGINT 0x01 /* long integer */
49: #define LONGDBL 0x02 /* long double; unimplemented */
50: #define SHORTINT 0x04 /* short integer */
51: #define ALT 0x08 /* alternate form */
52: #define LADJUST 0x10 /* left adjustment */
53: #define ZEROPAD 0x20 /* zero (as opposed to blank) pad */
54: #define HEXPREFIX 0x40 /* add 0x or 0X prefix */
55:
56: _doprnt(fmt0, argp, fp)
57: u_char *fmt0;
58: va_list argp;
59: register FILE *fp;
60: {
61: register u_char *fmt; /* format string */
62: register int ch; /* character from fmt */
63: register int cnt; /* return value accumulator */
64: register int n; /* random handy integer */
65: register char *t; /* buffer pointer */
66: double _double; /* double precision arguments %[eEfgG] */
67: u_long _ulong; /* integer arguments %[diouxX] */
68: int base; /* base for [diouxX] conversion */
69: int dprec; /* decimal precision in [diouxX] */
70: int fieldsz; /* field size expanded by sign, etc */
71: int flags; /* flags as above */
72: int fpprec; /* `extra' floating precision in [eEfgG] */
73: int prec; /* precision from format (%.3d), or -1 */
74: int realsz; /* field size expanded by decimal precision */
75: int size; /* size of converted field or string */
76: int width; /* width from format (%8d), or 0 */
77: char sign; /* sign prefix (' ', '+', '-', or \0) */
78: char softsign; /* temporary negative sign for floats */
79: char *digs; /* digits for [diouxX] conversion */
80: char buf[BUF]; /* space for %c, %[diouxX], %[eEfgG] */
81:
82: if (fp->_flag & _IORW) {
83: fp->_flag |= _IOWRT;
84: fp->_flag &= ~(_IOEOF|_IOREAD);
85: }
86: if ((fp->_flag & _IOWRT) == 0)
87: return (EOF);
88:
89: fmt = fmt0;
90: digs = "0123456789abcdef";
91: for (cnt = 0;; ++fmt) {
92: n = fp->_cnt;
93: for (t = (char *)fp->_ptr; (ch = *fmt) && ch != '%';
94: ++cnt, ++fmt)
95: if (--n < 0
96: #ifdef NEGATIVE_COUNT_KLUDGE
97: && (!(fp->_flag & _IOLBF) || -n >= fp->_bufsiz)
98: #endif
99: || ch == '\n' && fp->_flag & _IOLBF) {
100: fp->_cnt = n;
101: fp->_ptr = t;
102: (void) _flsbuf((u_char)ch, fp);
103: n = fp->_cnt;
104: t = (char *)fp->_ptr;
105: } else
106: *t++ = ch;
107: fp->_cnt = n;
108: fp->_ptr = t;
109: if (!ch)
110: return (cnt);
111:
112: flags = 0; dprec = 0; fpprec = 0; width = 0;
113: prec = -1;
114: sign = '\0';
115:
116: rflag: switch (*++fmt) {
117: case ' ':
118: /*
119: * ``If the space and + flags both appear, the space
120: * flag will be ignored.''
121: * -- ANSI X3J11
122: */
123: if (!sign)
124: sign = ' ';
125: goto rflag;
126: case '#':
127: flags |= ALT;
128: goto rflag;
129: case '*':
130: /*
131: * ``A negative field width argument is taken as a
132: * - flag followed by a positive field width.''
133: * -- ANSI X3J11
134: * They don't exclude field widths read from args.
135: */
136: if ((width = va_arg(argp, int)) >= 0)
137: goto rflag;
138: width = -width;
139: /* FALLTHROUGH */
140: case '-':
141: flags |= LADJUST;
142: goto rflag;
143: case '+':
144: sign = '+';
145: goto rflag;
146: case '.':
147: if (*++fmt == '*')
148: n = va_arg(argp, int);
149: else {
150: n = 0;
151: while (isascii(*fmt) && isdigit(*fmt))
152: n = 10 * n + todigit(*fmt++);
153: --fmt;
154: }
155: prec = n < 0 ? -1 : n;
156: goto rflag;
157: case '0':
158: /*
159: * ``Note that 0 is taken as a flag, not as the
160: * beginning of a field width.''
161: * -- ANSI X3J11
162: */
163: flags |= ZEROPAD;
164: goto rflag;
165: case '1': case '2': case '3': case '4':
166: case '5': case '6': case '7': case '8': case '9':
167: n = 0;
168: do {
169: n = 10 * n + todigit(*fmt);
170: } while (isascii(*++fmt) && isdigit(*fmt));
171: width = n;
172: --fmt;
173: goto rflag;
174: case 'L':
175: flags |= LONGDBL;
176: goto rflag;
177: case 'h':
178: flags |= SHORTINT;
179: goto rflag;
180: case 'l':
181: flags |= LONGINT;
182: goto rflag;
183: case 'c':
184: *(t = buf) = va_arg(argp, int);
185: size = 1;
186: sign = '\0';
187: goto pforw;
188: case 'D':
189: flags |= LONGINT;
190: /*FALLTHROUGH*/
191: case 'd':
192: case 'i':
193: ARG();
194: if ((long)_ulong < 0) {
195: _ulong = -_ulong;
196: sign = '-';
197: }
198: base = 10;
199: goto number;
200: case 'e':
201: case 'E':
202: case 'f':
203: case 'g':
204: case 'G':
205: _double = va_arg(argp, double);
206: /*
207: * don't do unrealistic precision; just pad it with
208: * zeroes later, so buffer size stays rational.
209: */
210: if (prec > MAXFRACT) {
211: if (*fmt != 'g' && *fmt != 'G' || (flags&ALT))
212: fpprec = prec - MAXFRACT;
213: prec = MAXFRACT;
214: }
215: else if (prec == -1)
216: prec = DEFPREC;
217: /*
218: * softsign avoids negative 0 if _double is < 0 and
219: * no significant digits will be shown
220: */
221: if (_double < 0) {
222: softsign = '-';
223: _double = -_double;
224: }
225: else
226: softsign = 0;
227: /*
228: * cvt may have to round up past the "start" of the
229: * buffer, i.e. ``intf("%.2f", (double)9.999);'';
230: * if the first char isn't NULL, it did.
231: */
232: *buf = NULL;
233: size = cvt(_double, prec, flags, &softsign, *fmt, buf,
234: buf + sizeof(buf));
235: if (softsign)
236: sign = '-';
237: t = *buf ? buf : buf + 1;
238: goto pforw;
239: case 'n':
240: if (flags & LONGINT)
241: *va_arg(argp, long *) = cnt;
242: else if (flags & SHORTINT)
243: *va_arg(argp, short *) = cnt;
244: else
245: *va_arg(argp, int *) = cnt;
246: break;
247: case 'O':
248: flags |= LONGINT;
249: /*FALLTHROUGH*/
250: case 'o':
251: ARG();
252: base = 8;
253: goto nosign;
254: case 'p':
255: /*
256: * ``The argument shall be a pointer to void. The
257: * value of the pointer is converted to a sequence
258: * of printable characters, in an implementation-
259: * defined manner.''
260: * -- ANSI X3J11
261: */
262: /* NOSTRICT */
263: _ulong = (u_long)va_arg(argp, void *);
264: base = 16;
265: goto nosign;
266: case 's':
267: if (!(t = va_arg(argp, char *)))
268: t = "(null)";
269: if (prec >= 0) {
270: /*
271: * can't use strlen; can only look for the
272: * NUL in the first `prec' characters, and
273: * strlen() will go further.
274: */
275: char *p, *memchr();
276:
277: if (p = memchr(t, 0, prec)) {
278: size = p - t;
279: if (size > prec)
280: size = prec;
281: } else
282: size = prec;
283: } else
284: size = strlen(t);
285: sign = '\0';
286: goto pforw;
287: case 'U':
288: flags |= LONGINT;
289: /*FALLTHROUGH*/
290: case 'u':
291: ARG();
292: base = 10;
293: goto nosign;
294: case 'X':
295: digs = "0123456789ABCDEF";
296: /* FALLTHROUGH */
297: case 'x':
298: ARG();
299: base = 16;
300: /* leading 0x/X only if non-zero */
301: if (flags & ALT && _ulong != 0)
302: flags |= HEXPREFIX;
303:
304: /* unsigned conversions */
305: nosign: sign = '\0';
306: /*
307: * ``... diouXx conversions ... if a precision is
308: * specified, the 0 flag will be ignored.''
309: * -- ANSI X3J11
310: */
311: number: if ((dprec = prec) >= 0)
312: flags &= ~ZEROPAD;
313:
314: /*
315: * ``The result of converting a zero value with an
316: * explicit precision of zero is no characters.''
317: * -- ANSI X3J11
318: */
319: t = buf + BUF;
320: if (_ulong != 0 || prec != 0) {
321: do {
322: *--t = digs[_ulong % base];
323: _ulong /= base;
324: } while (_ulong);
325: digs = "0123456789abcdef";
326: if (flags & ALT && base == 8 && *t != '0')
327: *--t = '0'; /* octal leading 0 */
328: }
329: size = buf + BUF - t;
330:
331: pforw:
332: /*
333: * All reasonable formats wind up here. At this point,
334: * `t' points to a string which (if not flags&LADJUST)
335: * should be padded out to `width' places. If
336: * flags&ZEROPAD, it should first be prefixed by any
337: * sign or other prefix; otherwise, it should be blank
338: * padded before the prefix is emitted. After any
339: * left-hand padding and prefixing, emit zeroes
340: * required by a decimal [diouxX] precision, then print
341: * the string proper, then emit zeroes required by any
342: * leftover floating precision; finally, if LADJUST,
343: * pad with blanks.
344: */
345:
346: /*
347: * compute actual size, so we know how much to pad
348: * fieldsz excludes decimal prec; realsz includes it
349: */
350: fieldsz = size + fpprec;
351: if (sign)
352: fieldsz++;
353: if (flags & HEXPREFIX)
354: fieldsz += 2;
355: realsz = dprec > fieldsz ? dprec : fieldsz;
356:
357: /* right-adjusting blank padding */
358: if ((flags & (LADJUST|ZEROPAD)) == 0 && width)
359: for (n = realsz; n < width; n++)
360: PUTC(' ');
361: /* prefix */
362: if (sign)
363: PUTC(sign);
364: if (flags & HEXPREFIX) {
365: PUTC('0');
366: PUTC((char)*fmt);
367: }
368: /* right-adjusting zero padding */
369: if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD)
370: for (n = realsz; n < width; n++)
371: PUTC('0');
372: /* leading zeroes from decimal precision */
373: for (n = fieldsz; n < dprec; n++)
374: PUTC('0');
375:
376: /* the string or number proper */
377: if (fp->_cnt - (n = size) >= 0 &&
378: (fp->_flag & _IOLBF) == 0) {
379: fp->_cnt -= n;
380: bcopy(t, (char *)fp->_ptr, n);
381: fp->_ptr += n;
382: } else
383: while (--n >= 0)
384: PUTC(*t++);
385: /* trailing f.p. zeroes */
386: while (--fpprec >= 0)
387: PUTC('0');
388: /* left-adjusting padding (always blank) */
389: if (flags & LADJUST)
390: for (n = realsz; n < width; n++)
391: PUTC(' ');
392: /* finally, adjust cnt */
393: cnt += width > realsz ? width : realsz;
394: break;
395: case '\0': /* "%?" prints ?, unless ? is NULL */
396: return (cnt);
397: default:
398: PUTC((char)*fmt);
399: cnt++;
400: }
401: }
402: /* NOTREACHED */
403: }
404:
405: static
406: cvt(number, prec, flags, signp, fmtch, startp, endp)
407: double number;
408: register int prec;
409: int flags;
410: u_char fmtch;
411: char *signp, *startp, *endp;
412: {
413: register char *p, *t;
414: register double fract;
415: int dotrim, expcnt, gformat;
416: double integer, tmp, modf();
417: char *exponent(), *round();
418:
419: dotrim = expcnt = gformat = 0;
420: fract = modf(number, &integer);
421:
422: /* get an extra slot for rounding. */
423: t = ++startp;
424:
425: /*
426: * get integer portion of number; put into the end of the buffer; the
427: * .01 is added for modf(356.0 / 10, &integer) returning .59999999...
428: */
429: for (p = endp - 1; integer; ++expcnt) {
430: tmp = modf(integer / 10, &integer);
431: *p-- = tochar((int)((tmp + .01) * 10));
432: }
433: switch(fmtch) {
434: case 'f':
435: /* reverse integer into beginning of buffer */
436: if (expcnt)
437: for (; ++p < endp; *t++ = *p);
438: else
439: *t++ = '0';
440: /*
441: * if precision required or alternate flag set, add in a
442: * decimal point.
443: */
444: if (prec || flags&ALT)
445: *t++ = '.';
446: /* if requires more precision and some fraction left */
447: if (fract) {
448: if (prec)
449: do {
450: fract = modf(fract * 10, &tmp);
451: *t++ = tochar((int)tmp);
452: } while (--prec && fract);
453: if (fract)
454: startp = round(fract, (int *)NULL, startp,
455: t - 1, (char)0, signp);
456: }
457: for (; prec--; *t++ = '0');
458: break;
459: case 'e':
460: case 'E':
461: eformat: if (expcnt) {
462: *t++ = *++p;
463: if (prec || flags&ALT)
464: *t++ = '.';
465: /* if requires more precision and some integer left */
466: for (; prec && ++p < endp; --prec)
467: *t++ = *p;
468: /*
469: * if done precision and more of the integer component,
470: * round using it; adjust fract so we don't re-round
471: * later.
472: */
473: if (!prec && ++p < endp) {
474: fract = 0;
475: startp = round((double)0, &expcnt, startp,
476: t - 1, *p, signp);
477: }
478: /* adjust expcnt for digit in front of decimal */
479: --expcnt;
480: }
481: /* until first fractional digit, decrement exponent */
482: else if (fract) {
483: /* adjust expcnt for digit in front of decimal */
484: for (expcnt = -1;; --expcnt) {
485: fract = modf(fract * 10, &tmp);
486: if (tmp)
487: break;
488: }
489: *t++ = tochar((int)tmp);
490: if (prec || flags&ALT)
491: *t++ = '.';
492: }
493: else {
494: *t++ = '0';
495: if (prec || flags&ALT)
496: *t++ = '.';
497: }
498: /* if requires more precision and some fraction left */
499: if (fract) {
500: if (prec)
501: do {
502: fract = modf(fract * 10, &tmp);
503: *t++ = tochar((int)tmp);
504: } while (--prec && fract);
505: if (fract)
506: startp = round(fract, &expcnt, startp,
507: t - 1, (char)0, signp);
508: }
509: /* if requires more precision */
510: for (; prec--; *t++ = '0');
511:
512: /* unless alternate flag, trim any g/G format trailing 0's */
513: if (gformat && !(flags&ALT)) {
514: while (t > startp && *--t == '0');
515: if (*t == '.')
516: --t;
517: ++t;
518: }
519: t = exponent(t, expcnt, fmtch);
520: break;
521: case 'g':
522: case 'G':
523: /* a precision of 0 is treated as a precision of 1. */
524: if (!prec)
525: ++prec;
526: /*
527: * ``The style used depends on the value converted; style e
528: * will be used only if the exponent resulting from the
529: * conversion is less than -4 or greater than the precision.''
530: * -- ANSI X3J11
531: */
532: if (expcnt > prec || !expcnt && fract && fract < .0001) {
533: /*
534: * g/G format counts "significant digits, not digits of
535: * precision; for the e/E format, this just causes an
536: * off-by-one problem, i.e. g/G considers the digit
537: * before the decimal point significant and e/E doesn't
538: * count it as precision.
539: */
540: --prec;
541: fmtch -= 2; /* G->E, g->e */
542: gformat = 1;
543: goto eformat;
544: }
545: /*
546: * reverse integer into beginning of buffer,
547: * note, decrement precision
548: */
549: if (expcnt)
550: for (; ++p < endp; *t++ = *p, --prec);
551: else
552: *t++ = '0';
553: /*
554: * if precision required or alternate flag set, add in a
555: * decimal point. If no digits yet, add in leading 0.
556: */
557: if (prec || flags&ALT) {
558: dotrim = 1;
559: *t++ = '.';
560: }
561: else
562: dotrim = 0;
563: /* if requires more precision and some fraction left */
564: if (fract) {
565: if (prec) {
566: do {
567: fract = modf(fract * 10, &tmp);
568: *t++ = tochar((int)tmp);
569: } while(!tmp);
570: while (--prec && fract) {
571: fract = modf(fract * 10, &tmp);
572: *t++ = tochar((int)tmp);
573: }
574: }
575: if (fract)
576: startp = round(fract, (int *)NULL, startp,
577: t - 1, (char)0, signp);
578: }
579: /* alternate format, adds 0's for precision, else trim 0's */
580: if (flags&ALT)
581: for (; prec--; *t++ = '0');
582: else if (dotrim) {
583: while (t > startp && *--t == '0');
584: if (*t != '.')
585: ++t;
586: }
587: }
588: return(t - startp);
589: }
590:
591: static char *
592: round(fract, exp, start, end, ch, signp)
593: double fract;
594: int *exp;
595: register char *start, *end;
596: char ch, *signp;
597: {
598: double tmp;
599:
600: if (fract)
601: (void)modf(fract * 10, &tmp);
602: else
603: tmp = todigit(ch);
604: if (tmp > 4)
605: for (;; --end) {
606: if (*end == '.')
607: --end;
608: if (++*end <= '9')
609: break;
610: *end = '0';
611: if (end == start) {
612: if (exp) { /* e/E; increment exponent */
613: *end = '1';
614: ++*exp;
615: }
616: else { /* f; add extra digit */
617: *--end = '1';
618: --start;
619: }
620: break;
621: }
622: }
623: /* ``"%.3f", (double)-0.0004'' gives you a negative 0. */
624: else if (*signp == '-')
625: for (;; --end) {
626: if (*end == '.')
627: --end;
628: if (*end != '0')
629: break;
630: if (end == start)
631: *signp = 0;
632: }
633: return(start);
634: }
635:
636: static char *
637: exponent(p, exp, fmtch)
638: register char *p;
639: register int exp;
640: u_char fmtch;
641: {
642: register char *t;
643: char expbuf[MAXEXP];
644:
645: *p++ = fmtch;
646: if (exp < 0) {
647: exp = -exp;
648: *p++ = '-';
649: }
650: else
651: *p++ = '+';
652: t = expbuf + MAXEXP;
653: if (exp > 9) {
654: do {
655: *--t = tochar(exp % 10);
656: } while ((exp /= 10) > 9);
657: *--t = tochar(exp);
658: for (; t < expbuf + MAXEXP; *p++ = *t++);
659: }
660: else {
661: *p++ = '0';
662: *p++ = tochar(exp);
663: }
664: return(p);
665: }
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