iostream.c

早期freebsd实现

//    This is part of the iostream library, providing input/output for C++.
//    Copyright (C) 1991, 1992 Per Bothner.
//
//    This library is free software; you can redistribute it and/or
//    modify it under the terms of the GNU Library General Public
//    License as published by the Free Software Foundation; either
//    version 2 of the License, or (at your option) any later version.
//
//    This library 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
//    Library General Public License for more details.
//
//    You should have received a copy of the GNU Library General Public
//    License along with this library; if not, write to the Free
//    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

#ifdef __GNUG__
#pragma implementation
#endif
#define _STREAM_COMPAT
#include "ioprivate.h"
#include <iostream.h>
#include <stdio.h>  /* Needed for sprintf */
#include <ctype.h>
#include <limits.h>
#include "floatio.h"

#define	BUF		(MAXEXP+MAXFRACT+1)	/* + decimal point */

//#define isspace(ch) ((ch)==' ' || (ch)=='\t' || (ch)=='\n')

istream::istream(streambuf *sb, ostream* tied) : ios(sb, tied)
{
    _flags |= ios::dont_close;
    _gcount = 0;
}

int skip_ws(streambuf* sb)
{
    int ch;
    for (;;) {
	ch = sb->sbumpc();
	if (ch == EOF || !isspace(ch))
	    return ch;
    }
}

istream& istream::get(char& c)
{
    if (ipfx1()) {
	int ch = _strbuf->sbumpc();
	if (ch == EOF) set(ios::eofbit|ios::failbit);
	else c = (char)ch;
    }
    return *this;
}

istream& istream::ignore(int n /* = 1 */, int delim /* = EOF */)
{
    if (ipfx1()) {
	register streambuf* sb = _strbuf;
	if (delim == EOF) {
	    _gcount = sb->ignore(n);
	    return *this;
	}
	_gcount = 0;
	for (;;) {
#if 0
	    if (n != MAXINT) // FIXME
#endif
	    if (--n < 0)
		break;
	    int ch = sb->sbumpc();
	    if (ch == EOF) {
		set(ios::eofbit|ios::failbit);
		break;
	    }
	    _gcount++;
	    if (ch == delim)
		break;
	}
    }
    return *this;
}

istream& istream::read(char *s, int n)
{
    if (ipfx1()) {
	_gcount = _strbuf->sgetn(s, n);
	if (_gcount != n)
	    set(ios::failbit);
    }
    return *this;
}

istream& istream::seekg(streampos pos)
{
    pos = _strbuf->seekpos(pos, ios::in);
    if (pos == streampos(EOF))
	set(ios::badbit);
    return *this;
}

istream& istream::seekg(streamoff off, _seek_dir dir)
{
    streampos pos = _strbuf->seekoff(off, dir, ios::in);
    if (pos == streampos(EOF))
	set(ios::badbit);
    return *this;
}

streampos istream::tellg()
{
    streampos pos = _strbuf->seekoff(0, ios::cur, ios::in);
    if (pos == streampos(EOF))
	set(ios::badbit);
    return pos;
}

istream& istream::scan(const char *format ...)
{
    if (ipfx0()) {
	va_list ap;
	va_start(ap, format);
	_strbuf->vscan(format, ap, this);
	va_end(ap);
    }
    return *this;
}

istream& istream::vscan(const char *format, _G_va_list args)
{
    if (ipfx0())
	_strbuf->vscan(format, args, this);
    return *this;
}

istream& istream::operator>>(char& c)
{
    if (ipfx0()) {
	int ch = _strbuf->sbumpc();
	if (ch == EOF)
	    set(ios::eofbit|ios::failbit);
	else
	    c = (char)ch;
    }
    return *this;
}

istream& istream::operator>>(char* ptr)
{
    if (ipfx0()) {
	register streambuf* sb = _strbuf;
	int ch = sb->sbumpc();
	if (ch == EOF)
	    set(ios::eofbit|ios::failbit);
	else {
	    int w = width(0);
	    *ptr++ = ch;
	    for (;;) {
		ch = sb->sbumpc();
		if (ch == EOF) {
		    set(ios::eofbit|ios::failbit);
		    break;
		}
		else if (isspace(ch)) {
		    sb->sputbackc(ch);
		    break;
		}
		else if (w == 1) {
		    set(ios::failbit);
		    sb->sputbackc(ch);
		    break;
		}
		else *ptr++ = ch;
		w--;
	    }
	}
    }
    *ptr = '\0';
    return *this;
}

#ifdef __GNUC__
#define LONGEST long long
#else
#define LONGEST long
#endif

static int read_int(istream& stream, unsigned LONGEST& val, int& neg)
{
    if (!stream.ipfx0())
	return 0;
    register streambuf* sb = stream.rdbuf();
    int base = 10;
    int ndigits = 0;
    register int ch = skip_ws(sb);
    if (ch == EOF)
	goto eof_fail;
    neg = 0;
    if (ch == '+') {
	ch = skip_ws(sb);
    }
    else if (ch == '-') {
	neg = 1;
	ch = skip_ws(sb);
    }
    if (ch == EOF) goto eof_fail;
    if (!(stream.flags() & ios::basefield)) {
	if (ch == '0') {
	    ch = sb->sbumpc();
	    if (ch == EOF) {
		val = 0;
		return 1;
	    }
	    if (ch == 'x' || ch == 'X') {
		base = 16;
		ch = sb->sbumpc();
		if (ch == EOF) goto eof_fail;
	    }
	    else {
		sb->sputbackc(ch);
		base = 8;
		ch = '0';
	    }
	}
    }
    else if ((stream.flags() & ios::basefield) == ios::hex)
	base = 16;
    else if ((stream.flags() & ios::basefield) == ios::oct)
	base = 8;
    val = 0;
    for (;;) {
	if (ch == EOF)
	    break;
	int digit;
	if (ch >= '0' && ch <= '9')
	    digit = ch - '0';
	else if (ch >= 'A' && ch <= 'F')
	    digit = ch - 'A' + 10;
	else if (ch >= 'a' && ch <= 'f')
	    digit = ch - 'a' + 10;
	else
	    digit = 999;
	if (digit >= base) {
	    sb->sputbackc(ch);
	    if (ndigits == 0)
		goto fail;
	    else
		return 1;
	}
	ndigits++;
	val = base * val + digit;
	ch = sb->sbumpc();
    }
    return 1;
  fail:
    stream.set(ios::failbit);
    return 0;
  eof_fail:
    stream.set(ios::failbit|ios::eofbit);
    return 0;
}

#define READ_INT(TYPE) \
istream& istream::operator>>(TYPE& i)\
{\
    unsigned LONGEST val; int neg;\
    if (read_int(*this, val, neg)) {\
	if (neg) val = -val;\
	i = (TYPE)val;\
    }\
    return *this;\
}

READ_INT(short)
READ_INT(unsigned short)
READ_INT(int)
READ_INT(unsigned int)
READ_INT(long)
READ_INT(unsigned long)
#ifdef __GNUG__
READ_INT(long long)
READ_INT(unsigned long long)
#endif

istream& istream::operator>>(double& x)
{
    if (ipfx0())
	scan("%lg", &x);
    return *this;
}

istream& istream::operator>>(float& x)
{
    if (ipfx0())
	scan("%g", &x);
    return *this;
}

istream& istream::operator>>(register streambuf* sbuf)
{
    if (ipfx0()) {
	register streambuf* inbuf = rdbuf();
	// FIXME: Should optimize!
	for (;;) {
	    register int ch = inbuf->sbumpc();
	    if (ch == EOF) {
		set(ios::eofbit);
		break;
	    }
	    if (sbuf->sputc(ch) == EOF) {
		set(ios::failbit);
		break;
	    }
	}
    }
    return *this;
}

ostream& ostream::operator<<(char c)
{
    if (opfx()) {
	int w = width(0);
	char fill_char = fill();
	register int padding = w > 0 ? w - 1 : 0;
	register streambuf *sb = _strbuf;
	if (!(flags() & ios::left)) // Default adjustment.
	    while (--padding >= 0) sb->sputc(fill_char);
	sb->sputc(c);
	if (flags() & ios::left) // Left adjustment.
	    while (--padding >= 0) sb->sputc(fill_char);
	osfx();
    }
    return *this;
}

static void write_int(ostream& stream, unsigned LONGEST val, int neg)
{
#define WRITE_BUF_SIZE (10 + sizeof(unsigned LONGEST) * 3)
    char buf[WRITE_BUF_SIZE];
    register char *buf_ptr = buf+WRITE_BUF_SIZE; // End of buf.
    char *show_base = "";
    int show_base_len = 0;

    // Now do the actual conversion, placing the result at the *end* of buf.
    // Note that we use separate code for decimal, octal, and hex,
    // so we can divide by optimizable constants.
    if ((stream.flags() & ios::basefield) == ios::oct) { // Octal
	if ((stream.flags() & ios::showbase) && (val != 0))
	    show_base = "0", show_base_len = 1;
	do {
	    *--buf_ptr = (val & 7) + '0';
	    val = val >> 3;
	} while (val != 0);
    }
    else if ((stream.flags() & ios::basefield) == ios::hex) { // Hex
	char *xdigs = (stream.flags() & ios::uppercase) ? "0123456789ABCDEF0X"
	    : "0123456789abcdef0x";
	do {
	    *--buf_ptr = xdigs[val & 15];
	    val = val >> 4;
	} while (val != 0);
	if (stream.flags() & ios::showbase) {
	    show_base = xdigs + 16; // Either "0X" or "0x".
	    show_base_len = 2;
	}
    }
    else { // Decimal
#ifdef __GNUC__
	// Optimization:  Only use long long when we need to.
	while (val > UINT_MAX) {
	    *--buf_ptr = (val % 10) + '0';
	    val /= 10;
	}
	// Use more efficient (int) arithmetic for the rest.
	register unsigned int ival = (unsigned int)val;