fmt.c

在x86平台上运行不可信任代码的sandbox。

				 * account for new digit
				 */
				if(z1)	/* 0.099 => 0.100 or 0.99 => 1.00*/
					z1--;
				else	/* 9.99 => 10.00 */
					point++;
			}
			z2 = 0;
			ndigits = newndigits;
		}	
		sufwid = 0;
		break;
	}
	
	/*
	 * if %g is given without FmtSharp, remove trailing zeros.
	 * must do after truncation, so that e.g. print %.3g 1.001
	 * produces 1, not 1.00.  sorry, but them's the rules.
	 */
	if(realchr == 'g' && !(fl & FmtSharp)) {
		if(z1+ndigits+z2 >= point) {
			if(z1+ndigits < point)
				z2 = point - (z1+ndigits);
			else{
				z2 = 0;
				while(z1+ndigits > point && digits[ndigits-1] == '0')
					ndigits--;
			}
		}
	}

	/*
	 * compute width of all digits and decimal point and suffix if any
	 */
	wid = z1+ndigits+z2;
	if(wid > point)
		wid += dotwid;
	else if(wid == point){
		if(fl & FmtSharp)
			wid += dotwid;
		else
			point++;	/* do not print any decimal point */
	}
	wid += sufwid;

	/*
	 * determine sign
	 */
	sign = 0;
	if(neg)
		sign = '-';
	else if(fl & FmtSign)
		sign = '+';
	else if(fl & FmtSpace)
		sign = ' ';
	if(sign)
		wid++;

	/*
	 * compute padding
	 */
	pad = 0;
	if((fl & FmtWidth) && fmt->width > wid)
		pad = fmt->width - wid;
	if(pad && !(fl & FmtLeft) && (fl & FmtZero)){
		z1 += pad;
		point += pad;
		pad = 0;
	}

	/*
	 * format the actual field.  too bad about doing this twice.
	 */
	if(fmt->runes){
		if(pad && !(fl & FmtLeft) && __rfmtpad(fmt, pad) < 0)
			return -1;
		rt = (Rune*)fmt->to;
		rs = (Rune*)fmt->stop;
		if(sign)
			FMTRCHAR(fmt, rt, rs, sign);
		while(z1>0 || ndigits>0 || z2>0) {
			if(z1 > 0){
				z1--;
				c = '0';
			}else if(ndigits > 0){
				ndigits--;
				c = *digits++;
			}else{
				z2--;
				c = '0';
			}
			FMTRCHAR(fmt, rt, rs, c);
			if(--point == 0) {
				for(p = dot; *p; ){
					p += chartorune(&r, p);
					FMTRCHAR(fmt, rt, rs, r);
				}
			}
		}
		fmt->nfmt += rt - (Rune*)fmt->to;
		fmt->to = rt;
		if(sufwid && __fmtcpy(fmt, suf, sufwid, sufwid) < 0)
			return -1;
		if(pad && (fl & FmtLeft) && __rfmtpad(fmt, pad) < 0)
			return -1;
	}else{
		if(pad && !(fl & FmtLeft) && __fmtpad(fmt, pad) < 0)
			return -1;
		t = (char*)fmt->to;
		s = (char*)fmt->stop;
		if(sign)
			FMTCHAR(fmt, t, s, sign);
		while(z1>0 || ndigits>0 || z2>0) {
			if(z1 > 0){
				z1--;
				c = '0';
			}else if(ndigits > 0){
				ndigits--;
				c = *digits++;
			}else{
				z2--;
				c = '0';
			}
			FMTCHAR(fmt, t, s, c);
			if(--point == 0)
				for(p=dot; *p; p++)
					FMTCHAR(fmt, t, s, *p);
		}
		fmt->nfmt += t - (char*)fmt->to;
		fmt->to = t;
		if(sufwid && __fmtcpy(fmt, suf, sufwid, sufwid) < 0)
			return -1;
		if(pad && (fl & FmtLeft) && __fmtpad(fmt, pad) < 0)
			return -1;
	}
	return 0;
}

/* -------------- fmt.c --------------- */
/* Copyright (c) 2002-2006 Lucent Technologies; see LICENSE */
// #include <stdarg.h>
// #include <string.h>
// #include "plan9.h"
// #include "fmt.h"
// #include "fmtdef.h"

enum
{
	Maxfmt = 64
};

typedef struct Convfmt Convfmt;
struct Convfmt
{
	int	c;
	volatile	Fmts	fmt;	/* for spin lock in fmtfmt; avoids race due to write order */
};

static struct
{
	/* lock by calling __fmtlock, __fmtunlock */
	int	nfmt;
	Convfmt	fmt[Maxfmt];
} fmtalloc;

static Convfmt knownfmt[] = {
	{ ' ',	__flagfmt },
	{ '#',	__flagfmt },
	{ '%',	__percentfmt },
	{ '\'',	__flagfmt },
	{ '+',	__flagfmt },
	{ ',',	__flagfmt },
	{ '-',	__flagfmt },
	{ 'C',	__runefmt },	/* Plan 9 addition */
	{ 'E',	__efgfmt },
#ifndef PLAN9PORT
	{ 'F',	__efgfmt },	/* ANSI only */
#endif
	{ 'G',	__efgfmt },
#ifndef PLAN9PORT
	{ 'L',	__flagfmt },	/* ANSI only */
#endif
	{ 'S',	__runesfmt },	/* Plan 9 addition */
	{ 'X',	__ifmt },
	{ 'b',	__ifmt },		/* Plan 9 addition */
	{ 'c',	__charfmt },
	{ 'd',	__ifmt },
	{ 'e',	__efgfmt },
	{ 'f',	__efgfmt },
	{ 'g',	__efgfmt },
	{ 'h',	__flagfmt },
#ifndef PLAN9PORT
	{ 'i',	__ifmt },		/* ANSI only */
#endif
	{ 'l',	__flagfmt },
	{ 'n',	__countfmt },
	{ 'o',	__ifmt },
	{ 'p',	__ifmt },
	{ 'r',	__errfmt },
	{ 's',	__strfmt },
#ifdef PLAN9PORT
	{ 'u',	__flagfmt },
#else
	{ 'u',	__ifmt },
#endif
	{ 'x',	__ifmt },
	{ 0,	nil }
};


int	(*fmtdoquote)(int);

/*
 * __fmtlock() must be set
 */
static int
__fmtinstall(int c, Fmts f)
{
	Convfmt *p, *ep;

	if(c<=0 || c>=65536)
		return -1;
	if(!f)
		f = __badfmt;

	ep = &fmtalloc.fmt[fmtalloc.nfmt];
	for(p=fmtalloc.fmt; p<ep; p++)
		if(p->c == c)
			break;

	if(p == &fmtalloc.fmt[Maxfmt])
		return -1;

	p->fmt = f;
	if(p == ep){	/* installing a new format character */
		fmtalloc.nfmt++;
		p->c = c;
	}

	return 0;
}

int
fmtinstall(int c, int (*f)(Fmt*))
{
	int ret;

	__fmtlock();
	ret = __fmtinstall(c, f);
	__fmtunlock();
	return ret;
}

static Fmts
fmtfmt(int c)
{
	Convfmt *p, *ep;

	ep = &fmtalloc.fmt[fmtalloc.nfmt];
	for(p=fmtalloc.fmt; p<ep; p++)
		if(p->c == c){
			while(p->fmt == nil)	/* loop until value is updated */
				;
			return p->fmt;
		}

	/* is this a predefined format char? */
	__fmtlock();
	for(p=knownfmt; p->c; p++)
		if(p->c == c){
			__fmtinstall(p->c, p->fmt);
			__fmtunlock();
			return p->fmt;
		}
	__fmtunlock();

	return __badfmt;
}

void*
__fmtdispatch(Fmt *f, void *fmt, int isrunes)
{
	Rune rune, r;
	int i, n;

	f->flags = 0;
	f->width = f->prec = 0;

	for(;;){
		if(isrunes){
			r = *(Rune*)fmt;
			fmt = (Rune*)fmt + 1;
		}else{
			fmt = (char*)fmt + chartorune(&rune, (char*)fmt);
			r = rune;
		}
		f->r = r;
		switch(r){
		case '\0':
			return nil;
		case '.':
			f->flags |= FmtWidth|FmtPrec;
			continue;
		case '0':
			if(!(f->flags & FmtWidth)){
				f->flags |= FmtZero;
				continue;
			}
			/* fall through */
		case '1': case '2': case '3': case '4':
		case '5': case '6': case '7': case '8': case '9':
			i = 0;
			while(r >= '0' && r <= '9'){
				i = i * 10 + r - '0';
				if(isrunes){
					r = *(Rune*)fmt;
					fmt = (Rune*)fmt + 1;
				}else{
					r = *(char*)fmt;
					fmt = (char*)fmt + 1;
				}
			}
			if(isrunes)
				fmt = (Rune*)fmt - 1;
			else
				fmt = (char*)fmt - 1;
		numflag:
			if(f->flags & FmtWidth){
				f->flags |= FmtPrec;
				f->prec = i;
			}else{
				f->flags |= FmtWidth;
				f->width = i;
			}
			continue;
		case '*':
			i = va_arg(f->args, int);
			if(i < 0){
				/*
				 * negative precision =>
				 * ignore the precision.
				 */
				if(f->flags & FmtPrec){
					f->flags &= ~FmtPrec;
					f->prec = 0;
					continue;
				}
				i = -i;
				f->flags |= FmtLeft;
			}
			goto numflag;
		}
		n = (*fmtfmt(r))(f);
		if(n < 0)
			return nil;
		if(n == 0)
			return fmt;
	}
}
/* -------------- fmtfd.c --------------- */
/* Copyright (c) 2002-2006 Lucent Technologies; see LICENSE */
// #include <stdarg.h>
// #include <string.h>
// #include "plan9.h"
// #include "fmt.h"
// #include "fmtdef.h"

/*
 * public routine for final flush of a formatting buffer
 * to a file descriptor; returns total char count.
 */
int
fmtfdflush(Fmt *f)
{
	if(__fmtFdFlush(f) <= 0)
		return -1;
	return f->nfmt;
}

/*
 * initialize an output buffer for buffered printing
 */
int
fmtfdinit(Fmt *f, int fd, char *buf, int size)
{
	f->runes = 0;
	f->start = buf;
	f->to = buf;
	f->stop = buf + size;
	f->flush = __fmtFdFlush;
	f->farg = (void*)(uintptr_t)fd;
	f->flags = 0;
	f->nfmt = 0;
	fmtlocaleinit(f, nil, nil, nil);
	return 0;
}
/* -------------- fmtfdflush.c --------------- */
/* Copyright (c) 2002-2006 Lucent Technologies; see LICENSE */
// #include <stdarg.h>
// #include <unistd.h>
// #include "plan9.h"
// #include "fmt.h"
// #include "fmtdef.h"

/*
 * generic routine for flushing a formatting buffer
 * to a file descriptor
 */
int
__fmtFdFlush(Fmt *f)
{
	int n;

	n = (char*)f->to - (char*)f->start;
	if(n && write((uintptr)f->farg, f->start, n) != n)
		return 0;
	f->to = f->start;
	return 1;
}
/* -------------- fmtlocale.c --------------- */
/* Copyright (c) 2004 Google Inc.; see LICENSE */

// #include <stdarg.h>
// #include <string.h>
// #include "plan9.h"
// #include "fmt.h"
// #include "fmtdef.h"

/*
 * Fill in the internationalization stuff in the State structure.
 * For nil arguments, provide the sensible defaults:
 *	decimal is a period
 *	thousands separator is a comma
 *	thousands are marked every three digits
 */
void
fmtlocaleinit(Fmt *f, char *decimal, char *thousands, char *grouping)
{
	if(decimal == nil || decimal[0] == '\0')
		decimal = ".";
	if(thousands == nil)
		thousands = ",";
	if(grouping == nil)
		grouping = "\3";
	f->decimal = decimal;
	f->thousands = thousands;
	f->grouping = grouping;
}

/*
 * We are about to emit a digit in e.g. %'d.  If that digit would
 * overflow a thousands (e.g.) grouping, tell the caller to emit
 * the thousands separator.  Always advance the digit counter
 * and pointer into the grouping descriptor.
 */
int
__needsep(int *ndig, char **grouping)
{
	int group;
	
	(*ndig)++;
	group = *(unsigned char*)*grouping;
	/* CHAR_MAX means no further grouping. \0 means we got the empty string */
	if(group == 0xFF || group == 0x7f || group == 0x00)
		return 0;
	if(*ndig > group){
		/* if we're at end of string, continue with this grouping; else advance */
		if((*grouping)[1] != '\0')
			(*grouping)++;
		*ndig = 1;
		return 1;
	}
	return 0;
}

/* -------------- fmtlock.c --------------- */
/* Copyright (c) 2002-2006 Lucent Technologies; see LICENSE */
// #include <stdarg.h>
// #include "plan9.h"
// #include "fmt.h"
// #include "fmtdef.h"

void
__fmtlock(void)
{
}

void
__fmtunlock(void)
{
}
/* -------------- fmtnull.c --------------- */
/* Copyright (c) 2004 Google Inc.; see LICENSE */
// #include <stdarg.h>
// #include <string.h>
// #include "plan9.h"
// #include "fmt.h"
// #include "fmtdef.h"

/*
 * Absorb output without using resources.
 */
static Rune nullbuf[32];

static int
__fmtnullflush(Fmt *f)
{
	f->to = nullbuf;
	f->nfmt = 0;
	return 0;
}

int
fmtnullinit(Fmt *f)
{
	memset(&f, 0, sizeof *f);
	f->runes = 1;
	f->start = nullbuf;
	f->to = nullbuf;
	f->stop = nullbuf+nelem(nullbuf);
	f->flush = __fmtnullflush;
	fmtlocaleinit(f, nil, nil, nil);
	return 0;
}

/* -------------- fmtprint.c --------------- */
/* Copyright (c) 2002-2006 Lucent Technologies; see LICENSE */
// #include <stdarg.h>
// #include <string.h>
// #include "plan9.h"
// #include "fmt.h"
// #include "fmtdef.h"

/*
 * format a string into the output buffer
 * designed for formats which themselves call fmt,
 * but ignore any width flags
 */
int
fmtprint(Fmt *f, char *fmt, ...)
{
	va_list va;
	int n;

	f->flags = 0;
	f->width = 0;
	f->prec = 0;
	VA_COPY(va, f->args);
	VA_END(f->args);
	va_start(f->args, fmt);
	n = dofmt(f, fmt);
	va_end(f->args);
	f->flags = 0;
	f->width = 0;
	f->prec = 0;
	VA_COPY(f->args,va);
	VA_END(va);
	if(n >= 0)
		return 0;
	return n;
}

/* -------------- fmtquote.c --------------- */
/* Copyright (c) 2002-2006 Lucent Technologies; see LICENSE */
// #include <stdarg.h>
// #include <string.h>
// #include "plan9.h"
// #include "fmt.h"
// #include "fmtdef.h"

/*
 * How many bytes of output UTF will be produced by quoting (if necessary) this string?
 * How many runes? How much of the input will be consumed?
 * The parameter q is filled in by __quotesetup.
 * The string may be UTF or Runes (s or r).
 * Return count does not include NUL.
 * Terminate the scan at the first of:
 *	NUL in input
 *	count exceeded in input
 *	count exceeded on output
 * *ninp is set to number of input bytes accepted.
 * nin may be <0 initially, to avoid checking input by count.
 */
void
__quotesetup(char *s, Rune *r, int nin, int nout, Quoteinfo *q, int sharp, int runesout)
{
	int w;
	Rune c;

	q->quoted = 0;
	q->nbytesout = 0;
	q->nrunesout = 0;
	q->nbytesin = 0;
	q->nrunesin = 0;
	if(sharp || nin==0 || (s && *s=='\0') || (r && *r=='\0')){
		if(nout < 2)
			return;
		q->quoted = 1;
		q->nbytesout = 2;
		q->nrunesout = 2;
	}
	for(; nin!=0; nin--){
		if(s)
			w = chartorune(&c, s);
		else{
			c = *r;
			w = runelen(c);
		}

		if(c == '\0')
			break;
		if(runesout){
			if(q->nrunesout+1 > nout)
				break;
		}else{
			if(q->nbytesout+w > nout)
				break;
		}

		if((c <= L' ') || (c == L'\'') || (fmtdoquote!=nil && fmtdoquote(c))){
			if(!q->quoted){
				if(runesout){
					if(1+q->nrunesout+1+1 > nout)	/* no room for quotes */
						break;
				}else{
					if(1+q->nbytesout+w+1 > nout)	/* no room for quotes */
						break;
				}
				q->nrunesout += 2;	/* include quotes */
				q->nbytesout += 2;	/* include quotes */
				q->quoted = 1;
			}
			if(c == '\'')	{
				if(runesout){
					if(1+q->nrunesout+1 > nout)	/* no room for quotes */
						break;
				}else{
					if(1+q->nbytesout+w > nout)	/* no room for quotes */
						break;
				}
				q->nbytesout++;
				q->nrunesout++;	/* quotes reproduce as two characters */
			}
		}

		/* advance input */
		if(s)
			s += w;
		else
			r++;
		q->nbytesin += w;
		q->nrunesin++;

		/* advance output */
		q->nbytesout += w;
		q->nrunesout++;

#ifndef PLAN9PORT
		/* ANSI requires precision in bytes, not Runes. */
		nin-= w-1;	/* and then n-- in the loop */
#endif
	}
}

static int
qstrfmt(char *sin, Rune *rin, Quoteinfo *q, Fmt *f)
{
	Rune r, *rm, *rme;
	char *t, *s, *m, *me;
	Rune *rt, *rs;
	ulong fl;
	int nc, w;

	m = sin;
	me = m + q->nbytesin;
	rm = rin;
	rme = rm + q->nrunesin;

	fl = f->flags;
	w = 0;
	if(fl & FmtWidth)
		w = f->width;
	if(f->runes){
		if(!(fl & FmtLeft) && __rfmtpad(f, w - q->nrunesout) < 0)
			return -1;
	}else{
		if(!(fl & FmtLeft) && __fmtpad(f, w - q->nbytesout) < 0)
			return -1;
	}
	t = (char*)f->to;