Checkpoint: pull in mpm; merge pic from Taj's version of the world

src/cmd/mpm/page.h

@@ -0,0 +1,119 @@
+extern queue	squeue;			// the three queues on which ranges reside
+extern queue	bfqueue;
+extern queue	ufqueue;
+
+extern double minfull;
+
+extern double coltol;
+
+int anymore();
+
+// The following is used in some calls to range::enqueue(int = 0).
+#define ANDBLOCK 1
+
+class page;
+
+enum { DRAFT = 0, FINAL = 1 };
+
+// The mergestream currpage->stage serves as a staging area for page makeup:
+// when primed, it contains a minimal acceptable chunk of input ranges.
+// The page must either take or leave everything that's on stage.
+class mergestream : public queue {
+	page	*currpage;		// current page that's accepting stuff
+  public:
+	mergestream(page *cp)	{ currpage = cp; unblock(); }
+	void	unblock();
+	int	prime();		// stage next legal chunk
+	void	pend();			// process pending chunk on stage
+};
+
+// The multicol currpage->twocol is the two-column piece of the page to which
+// two-column ranges are currently being added.
+// The page sets htavail to indicate how tall it is allowed to become.
+// All ranges on definite must be placed when the multicol is printed.
+// Each of these definite ranges also resides on one of column[0] and [1],
+// which represent the current best guess about how to divide definite
+// between the two columns.
+class multicol : public range {
+	page	*currpage;		// current page that's accepting stuff
+	stream	definite;		// definitely on page
+	stream	scratch;		// for trial compositions
+	stream	column[2];		// left (0) and right (1) columns
+	int	leftblocked;		// OK to add to left column?
+	int	htavail;		// max possible ht, set by page::tryout()
+	int	prevhtavail;		// max 2-colht last time we added something
+	friend	class page;
+public:
+	multicol(page *cp)	{ currpage = cp;
+				leftblocked = 0;
+				htavail = 0;
+				prevhtavail = -1;
+				setgoal(NOGOAL); }
+					// the two-column piece behaves as part
+					// of the stream of single-column input.
+	int	numcol()	{ return 1; }
+	int	nonempty()	{ return definite.more(); }
+	void	choosecol(range *, int);// add first arg to one or other column
+	void	choosecol(stream*, int);// add *all ranges on first arg*
+					// to one or other column
+					// NOT the same as a mapcar of the
+					// preceding function over the ranges
+					// on the first argument!
+	void	compose(int);		// divide into two columns
+	void	tryout();		// decide which column gets stage contents
+	void	stretch(int);		// justify both columns to given height
+	int	print(int curv, int col);
+	int	height();		// an upper bound on actual height
+	int	rawht()		{ return max(column[0].rawht(), column[1].rawht()); }
+	void	reheight(int *cv, int *mv)
+				{ *cv += height(); *mv = max(*mv, *cv); }
+	void	dump();
+	int	isvbox()	{ return nonempty(); }	// during trimspace()
+};
+
+// These sentinel ranges are used to separate the ranges on twocol::definite
+// into the chunks in which they came from the staging area.
+// Thus, they preserve the results of the computation that was done to prime
+// page::stage.
+class sentrange : public range {
+  public:
+	sentrange()		{ }
+	int	numcol()	{ return 2; }
+	int	issentinel()	{ return 1; }
+};
+
+class page {
+	int	pagesize;		// allowed maximum height
+	int	prevncol;		// was last item tried 1- or 2-column?
+	int	vsince;			// how many vboxes from "current" BS
+					// (to avoid putting a single line on
+					// a page with a very large floatable)
+	stream	definite;		// definitely on page, in input order
+	stream	scratch;		// playground in which to alter page
+	void	cmdproc();		// process any of several commands
+	void	parmproc();		// process any of several parameters
+	void	tryout();		// see whether current stage contents fit
+	void	compose(int);		// float and trim current page contents
+	void	makescratch(int);	// fill scratch area
+	void	commit();		// accept the items on stage
+	void	welsh();		// reject the items on stage
+	void	adddef(range *r);	// add to one of the definite queues
+					// (definite or twocol->definite)
+  public:
+	mergestream *stage;
+	friend	class mergestream;
+	multicol *twocol;
+	friend class multicol;
+	page(int p)	{ pagesize = p;
+			prevncol = 1;
+			vsince = 0;
+			stage = new mergestream(this);
+			twocol = new multicol(this); }
+	~page()	{ definite.freeall(); scratch.freeall(); }
+	void	fill();
+	int	blank()	{ return !definite.more() && !twocol->definite.more();}
+	void	print();
+};
+
+// functions in page.c
+int main(int, char **);