vfile.c

举世闻名的joe记事本源程序

VFILE *vfile;
unsigned char c;
{
	vseek(vfile, vtell(vfile));
	return vputc(vfile, c);
}

short vgetw(vfile)
VFILE *vfile;
{
	short w;

	if (vtell(vfile) + 2 > vsize(vfile))
		return -1;
	w = vgetc(vfile);
	w += ((short) vgetc(vfile) << 8);
	return w;
}

short vputw(vfile, w)
VFILE *vfile;
short w;
{
	vputc(vfile, w);
	vputc(vfile, w >> 8);
	return w;
}

long vgetl(vfile)
VFILE *vfile;
{
	long w;

	if (vtell(vfile) + 4 > vsize(vfile))
		return -1;
	w = vgetc(vfile);
	w += ((long) vgetc(vfile) << 8);
	w += ((long) vgetc(vfile) << 16);
	w += ((long) vgetc(vfile) << 24);
	return w;
}

long vputl(vfile, w)
VFILE *vfile;
long w;
{
	vputc(vfile, w);
	vputc(vfile, w >> 8);
	vputc(vfile, w >> 16);
	vputc(vfile, w >> 24);
	return w;
}

int _rc(vfile, addr)
VFILE *vfile;
long addr;
{
	if (vfile->vpage1)
		vunlock(vfile->vpage1);
	vfile->vpage1 = vlock(vfile, vfile->addr = (addr & ~(long) (PGSIZE - 1)));
	return rc(vfile, addr);
}

int _wc(vfile, addr, c)
VFILE *vfile;
long addr;
unsigned char c;
{
	if (addr + 1 > vsize(vfile))
		my_valloc(vfile, addr + 1 - vsize(vfile));
	if (vfile->vpage1)
		vunlock(vfile->vpage1);
	vfile->vpage1 = vlock(vfile, vfile->addr = (addr & ~(long) (PGSIZE - 1)));
	return wc(vfile, addr, c);
}

short rw(vfile, addr)
VFILE *vfile;
long addr;
{
	short c;

	if (addr + 2 > vsize(vfile))
		return -1;
	c = rc(vfile, addr);
	c += ((short) rc(vfile, addr + 1) << 8);
	return c;
}

short ww(vfile, addr, c)
VFILE *vfile;
long addr;
short c;
{
	if (addr + 2 > vsize(vfile))
		my_valloc(vfile, addr + 2 - vsize(vfile));
	wc(vfile, addr, c);
	wc(vfile, addr + 1, c >> 8);
	return c;
}

long rl(vfile, addr)
VFILE *vfile;
long addr;
{
	long c;

	if (addr + 4 > vsize(vfile))
		return -1;
	c = rc(vfile, addr);
	c += ((long) rc(vfile, addr + 1) << 8);
	c += ((long) rc(vfile, addr + 2) << 16);
	c += ((long) rc(vfile, addr + 3) << 24);
	return c;
}

long wl(vfile, addr, c)
VFILE *vfile;
long addr;
long c;
{
	if (addr + 4 > vsize(vfile))
		my_valloc(vfile, addr + 4 - vsize(vfile));
	wc(vfile, addr, c);
	wc(vfile, addr + 1, c >> 8);
	wc(vfile, addr + 2, c >> 16);
	wc(vfile, addr + 3, c >> 24);
	return c;
}

void vread(v, blk, size)
VFILE *v;
unsigned char *blk;
int size;
{
	long addr = vtell(v);
	unsigned char *src;
	int x;

	while (size) {
		src = vlock(v, addr);
		x = PGSIZE - (addr & (PGSIZE - 1));
		if (x >= size) {
			vseek(v, addr + size);
			mcpy(blk, src, size);
			vunlock(src);
			return;
		}
		size -= x;
		addr += x;
		mcpy(blk, src, x);
		blk += x;
		vunlock(src);
	}
	vseek(v, addr);
}

void vwrite(v, blk, size)
VFILE *v;
unsigned char *blk;
int size;
{
	long addr = vtell(v);
	unsigned char *src;
	int x;

	if (addr + size > vsize(v))
		my_valloc(v, addr + size - vsize(v));
	while (size) {
		src = vlock(v, addr);
		x = PGSIZE - (addr & (PGSIZE - 1));
		if (x >= size) {
			vseek(v, addr + size);
			mcpy(src, blk, size);
			vchanged(src);
			vunlock(src);
			return;
		}
		size -= x;
		addr += x;
		mcpy(src, blk, x);
		blk += x;
		vchanged(src);
		vunlock(src);
	}
	vseek(v, addr);
}

/* Write zstring to vfile */

void vputs(v, s)
VFILE *v;
unsigned char *s;
{
	while (*s) {
		vputc(v, *s);
		++s;
	}
}

/* Read a line from a file.  Remove '\n' if there was any */

unsigned char *vgets(v, s)
VFILE *v;
unsigned char *s;
{
	unsigned char *b, *a, *x, *y;
	int cnt;

	/* Return with NULL if at end of file */
	if (vtell(v) == vsize(v)) {
		vsrm(s);
		return NULL;
	}

	/* Create string if it doesn't exist */
	if (!s)
		s = vsmk(80);

	/* Zero string length */
	sLen(s) = 0;

      loop:

	/* Set b to end of string, a to page pointer, and cnt to min which ever
	 * (string or page) has the least space left
	 */
	b = s + sLen(s);
	a = v->bufp;
	cnt = Imin(sSIZ(s) - sLen(s), v->left - v->lv);

	/* Copy until \n is found or until page or buffer out of space */
	if (cnt >= 16)
		do {
			if ((b[0] = a[0]) == '\n') {
				a += 1;
				b += 1;
				goto ovr;
			}
			if ((b[1] = a[1]) == '\n') {
				a += 2;
				b += 2;
				cnt -= 1;
				goto ovr;
			}
			if ((b[2] = a[2]) == '\n') {
				a += 3;
				b += 3;
				cnt -= 2;
				goto ovr;
			}
			if ((b[3] = a[3]) == '\n') {
				a += 4;
				b += 4;
				cnt -= 3;
				goto ovr;
			}
			if ((b[4] = a[4]) == '\n') {
				a += 5;
				b += 5;
				cnt -= 4;
				goto ovr;
			}
			if ((b[5] = a[5]) == '\n') {
				a += 6;
				b += 6;
				cnt -= 5;
				goto ovr;
			}
			if ((b[6] = a[6]) == '\n') {
				a += 7;
				b += 7;
				cnt -= 6;
				goto ovr;
			}
			if ((b[7] = a[7]) == '\n') {
				a += 8;
				b += 8;
				cnt -= 7;
				goto ovr;
			}
			if ((b[8] = a[8]) == '\n') {
				a += 9;
				b += 9;
				cnt -= 8;
				goto ovr;
			}
			if ((b[9] = a[9]) == '\n') {
				a += 10;
				b += 10;
				cnt -= 9;
				goto ovr;
			}
			if ((b[10] = a[10]) == '\n') {
				a += 11;
				b += 11;
				cnt -= 10;
				goto ovr;
			}
			if ((b[11] = a[11]) == '\n') {
				a += 12;
				b += 12;
				cnt -= 11;
				goto ovr;
			}
			if ((b[12] = a[12]) == '\n') {
				a += 13;
				b += 13;
				cnt -= 12;
				goto ovr;
			}
			if ((b[13] = a[13]) == '\n') {
				a += 14;
				b += 14;
				cnt -= 13;
				goto ovr;
			}
			if ((b[14] = a[14]) == '\n') {
				a += 15;
				b += 15;
				cnt -= 14;
				goto ovr;
			}
			if ((b[15] = a[15]) == '\n') {
				a += 16;
				b += 16;
				cnt -= 15;
				goto ovr;
			}
		} while (a += 16, b += 16, (cnt -= 16) >= 16);

/*
	x = a;
	y = b;
	a += cnt - 15;
	b += cnt - 15;
	switch(cnt) {
	case 15:	if((b[0]=a[0])=='\n') { a+=1; b+=1; goto zif; }
	case 14:	if((b[1]=a[1])=='\n') { a+=2; b+=2; goto zif; }
	case 13:	if((b[2]=a[2])=='\n') { a+=3; b+=3; goto zif; }
	case 12:	if((b[3]=a[3])=='\n') { a+=4; b+=4; goto zif; }
	case 11:	if((b[4]=a[4])=='\n') { a+=5; b+=5; goto zif; }
	case 10:	if((b[5]=a[5])=='\n') { a+=6; b+=6; goto zif; }
	case 9:		if((b[6]=a[6])=='\n')  { a+=7; b+=7; goto zif; }
	case 8:		if((b[7]=a[7])=='\n')  { a+=8; b+=8; goto zif; }
	case 7:		if((b[8]=a[8])=='\n')  { a+=9; b+=9; goto zif; }
	case 6:		if((b[9]=a[9])=='\n')  { a+=10; b+=10; goto zif; }
	case 5:		if((b[10]=a[10])=='\n'){ a+=11; b+=11; goto zif; }
	case 4:		if((b[11]=a[11])=='\n'){ a+=12; b+=12; goto zif; }
	case 3:		if((b[12]=a[12])=='\n'){ a+=13; b+=13; goto zif; }
	case 2:		if((b[13]=a[13])=='\n'){ a+=14; b+=14; goto zif; }
	case 1:		if((b[14]=a[14])=='\n'){ a+=15; b+=15; goto zif; }
	}
	a = x + cnt;
	b = y + cnt;
	cnt=0;
	goto ovr;
zif:	cnt -= a - x - 1;
*/

	if (cnt)
		do {
			if ((*b++ = *a++) == '\n')
				break;
		} while (--cnt);

      ovr:

	/* Update string and page data */
	sLen(s) = b - s;
	v->left -= a - v->bufp;
	v->bufp = a;

	if (!cnt)
		if (vtell(v) == vsize(v))
			b[0] = 0;
		else {
			if (sLen(s) == sSiz(s))
				s = vsensure(s, sLen(s) + (sLen(s) >> 1) + 16);
			if (!v->left)
				vseek(v, vtell(v));
			goto loop;
	} else
		b[-1] = 0;

	return s;
}
#endif