build.c

来自「这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易」· C语言 代码 · 共 2,670 行 · 第 1/5 页

					additem(ps, textit(ps, _Strndup(buf, p-buf)), nil);
				p = buf;
				addnbsp(ps);
				j = i + 1;
				continue;
			}
			if(c < 256 && isspace(c)) {
				if(i > j)
					p = _Stradd(p, s+j, i-j);
				*p++ = ' ';
				while(i < n - 1) {
					c = s[i + 1];
					if(c >= 256 || !isspace(c))
						break;
					i++;
				}
				j = i + 1;
			}
			if(i - j >= 100) {
				p = _Stradd(p, s+j, i+1-j);
				j = i + 1;
			}
			if(p-buf >= 100) {
				additem(ps, textit(ps, _Strndup(buf, p-buf)), nil);
				p = buf;
			}
		}
		if(i > j && j < n) {
			assert(p+i-j < buf+SMALLBUFSIZE-1);
			p = _Stradd(p, s+j, i-j);
		}
		// don't add a space if previous item ended in a space
		if(p-buf == 1 && buf[0] == ' ' && ps->lastit != nil) {
			it = ps->lastit;
			if(it->tag == Itexttag) {
				ss = ((Itext*)it)->s;
				k = _Strlen(ss);
				if(k > 0 && ss[k] == ' ')
					p = buf;
			}
		}
		if(p > buf)
			additem(ps, textit(ps, _Strndup(buf, p-buf)), nil);
		free(s);
	}
}

// Add a break to ps->curstate, with extra space if sp is true.
// If there was a previous break, combine this one's parameters
// with that to make the amt be the max of the two and the clr
// be the most general. (amt will be 0 or 1)
// Also, if the immediately preceding item was a text item,
// trim any whitespace from the end of it, if not in literal mode.
// Finally, if this is at the very beginning of the item list
// (the only thing there is a null spacer), then don't add the space.
static void
addbrk(Pstate* ps, int sp, int clr)
{
	int	state;
	Rune*	l;
	int		nl;
	Rune*	r;
	int		nr;
	Itext*	t;
	Rune*	s;

	state = ps->curstate;
	clr = clr|(state&(IFcleft|IFcright));
	if(sp && !(ps->lastit == ps->items))
		sp = IFbrksp;
	else
		sp = 0;
	ps->curstate = IFbrk|sp|(state&~(IFcleft|IFcright))|clr;
	if(ps->lastit != ps->items) {
		if(!ps->literal && ps->lastit->tag == Itexttag) {
			t = (Itext*)ps->lastit;
			_splitr(t->s, _Strlen(t->s), notwhitespace, &l, &nl, &r, &nr);
			// try to avoid making empty items
			// but not crucial f the occasional one gets through
			if(nl == 0 && ps->prelastit != nil) {
				ps->lastit = ps->prelastit;
				ps->lastit->next = nil;
				ps->prelastit = nil;
			}
			else {
				s = t->s;
				if(nl == 0) {
					// need a non-nil pointer to empty string
					// (_Strdup(L"") returns nil)
					t->s = emalloc(sizeof(Rune));
					t->s[0] = 0;
				}
				else
					t->s = _Strndup(l, nl);
				if(s)
					free(s);
			}
		}
	}
}

// Add break due to a <br> or a newline within a preformatted section.
// We add a null item first, with current font's height and ascent, to make
// sure that the current line takes up at least that amount of vertical space.
// This ensures that <br>s on empty lines cause blank lines, and that
// multiple <br>s in a row give multiple blank lines.
// However don't add the spacer if the previous item was something that
// takes up space itself.
static void
addlinebrk(Pstate* ps, int clr)
{
	int	obrkstate;
	int	b;

	// don't want break before our null item unless the previous item
	// was also a null item for the purposes of line breaking
	obrkstate = ps->curstate&(IFbrk|IFbrksp);
	b = IFnobrk;
	if(ps->lastit != nil) {
		if(ps->lastit->tag == Ispacertag) {
			if(((Ispacer*)ps->lastit)->spkind == ISPvline)
				b = IFbrk;
		}
	}
	ps->curstate = (ps->curstate&~(IFbrk|IFbrksp))|b;
	additem(ps, newispacer(ISPvline), nil);
	ps->curstate = (ps->curstate&~(IFbrk|IFbrksp))|obrkstate;
	addbrk(ps, 0, clr);
}

// Add a nonbreakable space
static void
addnbsp(Pstate* ps)
{
	// if nbsp comes right where a break was specified,
	// do the break anyway (nbsp is being used to generate undiscardable
	// space rather than to prevent a break)
	if((ps->curstate&IFbrk) == 0)
		ps->curstate |= IFnobrk;
	additem(ps, newispacer(ISPhspace), nil);
	// but definitely no break on next item
	ps->curstate |= IFnobrk;
}

// Change hang in ps.curstate by delta.
// The amount is in 1/10ths of tabs, and is the amount that
// the current contiguous set of items with a hang value set
// is to be shifted left from its normal (indented) place.
static void
changehang(Pstate* ps, int delta)
{
	int	amt;

	amt = (ps->curstate&IFhangmask) + delta;
	if(amt < 0) {
		if(warn)
			fprint(2, "warning: hang went negative\n");
		amt = 0;
	}
	ps->curstate = (ps->curstate&~IFhangmask)|amt;
}

// Change indent in ps.curstate by delta.
static void
changeindent(Pstate* ps, int delta)
{
	int	amt;

	amt = ((ps->curstate&IFindentmask) >> IFindentshift) + delta;
	if(amt < 0) {
		if(warn)
			fprint(2, "warning: indent went negative\n");
		amt = 0;
	}
	ps->curstate = (ps->curstate&~IFindentmask)|(amt << IFindentshift);
}

// Push val on top of stack, and also return value pushed
static int
push(Stack* stk, int val)
{
	if(stk->n == Nestmax) {
		if(warn)
			fprint(2, "warning: build stack overflow\n");
	}
	else
		stk->slots[stk->n++] = val;
	return val;
}

// Pop top of stack
static void
pop(Stack* stk)
{
	if(stk->n > 0)
		--stk->n;
}

//Return top of stack, using dflt if stack is empty
static int
top(Stack* stk, int dflt)
{
	if(stk->n == 0)
		return dflt;
	return stk->slots[stk->n-1];
}

// pop, then return new top, with dflt if empty
static int
popretnewtop(Stack* stk, int dflt)
{
	if(stk->n == 0)
		return dflt;
	stk->n--;
	if(stk->n == 0)
		return dflt;
	return stk->slots[stk->n-1];
}

// Copy fromstk entries into tostk
static void
copystack(Stack* tostk, Stack* fromstk)
{
	int n;

	n = fromstk->n;
	tostk->n = n;
	memmove(tostk->slots, fromstk->slots, n*sizeof(int));
}

static void
popfontstyle(Pstate* ps)
{
	pop(&ps->fntstylestk);
	setcurfont(ps);
}

static void
pushfontstyle(Pstate* ps, int sty)
{
	push(&ps->fntstylestk, sty);
	setcurfont(ps);
}

static void
popfontsize(Pstate* ps)
{
	pop(&ps->fntsizestk);
	setcurfont(ps);
}

static void
pushfontsize(Pstate* ps, int sz)
{
	push(&ps->fntsizestk, sz);
	setcurfont(ps);
}

static void
setcurfont(Pstate* ps)
{
	int	sty;
	int	sz;

	sty = top(&ps->fntstylestk, FntR);
	sz = top(&ps->fntsizestk, Normal);
	if(sz < Tiny)
		sz = Tiny;
	if(sz > Verylarge)
		sz = Verylarge;
	ps->curfont = sty*NumSize + sz;
}

static void
popjust(Pstate* ps)
{
	pop(&ps->juststk);
	setcurjust(ps);
}

static void
pushjust(Pstate* ps, int j)
{
	push(&ps->juststk, j);
	setcurjust(ps);
}

static void
setcurjust(Pstate* ps)
{
	int	j;
	int	state;

	j = top(&ps->juststk, ALleft);
	if(j != ps->curjust) {
		ps->curjust = j;
		state = ps->curstate;
		state &= ~(IFrjust|IFcjust);
		if(j == ALcenter)
			state |= IFcjust;
		else if(j == ALright)
			state |= IFrjust;
		ps->curstate = state;
	}
}

// Do final rearrangement after table parsing is finished
// and assign cells to grid points
static void
finish_table(Table* t)
{
	int	ncol;
	int	nrow;
	int	r;
	Tablerow*	rl;
	Tablecell*	cl;
	int*	rowspancnt;
	Tablecell**	rowspancell;
	int	ri;
	int	ci;
	Tablecell*	c;
	Tablecell*	cnext;
	Tablerow*	row;
	Tablerow*	rownext;
	int	rcols;
	int	newncol;
	int	k;
	int	j;
	int	cspan;
	int	rspan;
	int	i;

	rl = t->rows;
	t->nrow = nrow = _listlen((List*)rl);
	t->rows = (Tablerow*)emalloc(nrow * sizeof(Tablerow));
	ncol = 0;
	r = nrow - 1;
	for(row = rl; row != nil; row = rownext) {
		// copy the data from the allocated Tablerow into the array slot
		t->rows[r] = *row;
		rownext = row->next;
		row = &t->rows[r];
		r--;
		rcols = 0;
		c = row->cells;

		// If rowspan is > 1 but this is the last row,
		// reset the rowspan
		if(c != nil && c->rowspan > 1 && r == nrow-2)
				c->rowspan = 1;

		// reverse row->cells list (along nextinrow pointers)
		row->cells = nil;
		while(c != nil) {
			cnext = c->nextinrow;
			c->nextinrow = row->cells;
			row->cells = c;
			rcols += c->colspan;
			c = cnext;
		}
		if(rcols > ncol)
			ncol = rcols;
	}
	t->ncol = ncol;
	t->cols = (Tablecol*)emalloc(ncol * sizeof(Tablecol));

	// Reverse cells just so they are drawn in source order.
	// Also, trim their contents so they don't end in whitespace.
	t->cells = (Tablecell*)_revlist((List*)t->cells);
	for(c = t->cells; c != nil; c= c->next)
		trim_cell(c);
	t->grid = (Tablecell***)emalloc(nrow * sizeof(Tablecell**));
	for(i = 0; i < nrow; i++)
		t->grid[i] = (Tablecell**)emalloc(ncol * sizeof(Tablecell*));

	// The following arrays keep track of cells that are spanning
	// multiple rows;  rowspancnt[i] is the number of rows left
	// to be spanned in column i.
	// When done, cell's (row,col) is upper left grid point.
	rowspancnt = (int*)emalloc(ncol * sizeof(int));
	rowspancell = (Tablecell**)emalloc(ncol * sizeof(Tablecell*));
	for(ri = 0; ri < nrow; ri++) {
		row = &t->rows[ri];
		cl = row->cells;
		ci = 0;
		while(ci < ncol || cl != nil) {
			if(ci < ncol && rowspancnt[ci] > 0) {
				t->grid[ri][ci] = rowspancell[ci];
				rowspancnt[ci]--;
				ci++;
			}
			else {
				if(cl == nil) {
					ci++;
					continue;
				}
				c = cl;
				cl = cl->nextinrow;
				cspan = c->colspan;
				rspan = c->rowspan;
				if(ci + cspan > ncol) {
					// because of row spanning, we calculated
					// ncol incorrectly; adjust it
					newncol = ci + cspan;
					t->cols = (Tablecol*)erealloc(t->cols, newncol * sizeof(Tablecol));
					rowspancnt = (int*)erealloc(rowspancnt, newncol * sizeof(int));
					rowspancell = (Tablecell**)erealloc(rowspancell, newncol * sizeof(Tablecell*));
					k = newncol-ncol;
					memset(t->cols+ncol, 0, k*sizeof(Tablecol));
					memset(rowspancnt+ncol, 0, k*sizeof(int));
					memset(rowspancell+ncol, 0, k*sizeof(Tablecell*));
					for(j = 0; j < nrow; j++) {
						t->grid[j] = (Tablecell**)erealloc(t->grid[j], newncol * sizeof(Tablecell*));
						memset(t->grid[j], 0, k*sizeof(Tablecell*));
					}
					t->ncol = ncol = newncol;
				}
				c->row = ri;
				c->col = ci;
				for(i = 0; i < cspan; i++) {
					t->grid[ri][ci] = c;
					if(rspan > 1) {
						rowspancnt[ci] = rspan - 1;
						rowspancell[ci] = c;
					}
					ci++;
				}
			}
		}
	}
	free(rowspancnt);
	free(rowspancell);
}

// Remove tail of cell content until it isn't whitespace.
static void
trim_cell(Tablecell* c)
{
	int	dropping;
	Rune*	s;
	Rune*	x;
	Rune*	y;
	int		nx;
	int		ny;
	Item*	p;
	Itext*	q;
	Item*	pprev;

	dropping = 1;
	while(c->content != nil && dropping) {
		p = c->content;
		pprev = nil;
		while(p->next != nil) {
			pprev = p;
			p = p->next;
		}
		dropping = 0;
		if(!(p->state&IFnobrk)) {
			if(p->tag == Itexttag) {
				q = (Itext*)p;
				s = q->s;
				_splitr(s, _Strlen(s), notwhitespace, &x, &nx, &y, &ny);
				if(nx != 0 && ny != 0) {
					q->s = _Strndup(x, nx);
					free(s);
				}
				break;
			}
		}
		if(dropping) {
			if(pprev == nil)
				c->content = nil;
			else
				pprev->next = nil;
			freeitem(p);
		}
	}
}

// Caller must free answer (eventually).
static Rune*
listmark(uchar ty, int n)
{
	Rune*	s;
	Rune*	t;
	int	n2;
	int	i;

	s = nil;
	switch(ty) {
	case LTdisc:
	case LTsquare:
	case LTcircle:
		s = _newstr(1);
		s[0] = (ty == LTdisc)? 0x2022		// bullet
			: ((ty == LTsquare)? 0x220e	// filled square
			    : 0x2218);				// degree
		s[1] = 0;
		break;

	case LT1:
		t = _ltoStr(n);
		n2 = _Strlen(t);
		s = _newstr(n2+1);
		t = _Stradd(s, t, n2);
		*t++ = '.';
		*t = 0;
		break;

	case LTa:
	case LTA:
		n--;
		i = 0;
		if(n < 0)
			n = 0;
		s = _newstr((n <= 25)? 2 : 3);
		if(n > 25) {
			n2 = n%26;
			n /= 26;
			if(n2 > 25)
				n2 = 25;
			s[i++] = n2 + (ty == LTa)? 'a' : 'A';
		}
		s[i++] = n + (ty == LTa)? 'a' : 'A';
		s[i++] = '.';
		s[i] = 0;
		break;

	case LTi:
	case LTI:
		if(n >= NROMAN) {
			if(warn)
				fprint(2, "warning: unimplemented roman number > %d\n", NROMAN);