#include	"defs.h"

/*
 * Read display list into dynamic area.
 *
 * fn = file name; null name produces a clean slate.
 */

#define BLKSIZ 512

input(fn)
	REG STRING fn;
{
	REG INT n;
	REG ADR	a;
	DL	p;
	ERR	saverr;

	setname(fn);
	newslate(fn);
	copyjmp(onerror, saverr);
	if(n=setjmp(onerror)){
		newslate(fn);
		copyjmp(saverr, onerror);
		return;
	}
	fileopen(filename, 0);
	a = adr(dstart)-BLKSIZ;
	do{
		a += BLKSIZ;
		morecore(BLKSIZ);
		n=read(openfd, a, BLKSIZ);
	}
	while(n==BLKSIZ);


	/* too high but will be reset shortly
	 * succa must be safe if the type is checked
	 */
	dend = dlim;
	fileclose();
	if(((p = dstart)->type != 'Z')
	    || version() != VERSION)
		error("bad .g file");
	arbchip = 1;
	p = dstart;

	while(p) {
		p=succa(p);
		switch(p->type){
		case 'Z':
			dend = succa(p);
			p=0;
			break;
		case 'w':
			if((p->flag&END)==0)
				p->flag |= DIRTY;
		case 'J':
		case 'c':
			{
				STRING	n = dln(p)->name;

				if(*n++ == '$' && number(n)) {
					INT i;

					if((i=geti(n))>=arbchip)
						arbchip = i+1;
				}
			}
		}
	}

	cleanall();
	copyjmp(saverr, onerror);
}

/*
 * Initialize dynamic area to be empty.
 */

LOC newslate(fn)
	STRING	fn;
{
	REG DL p;
	REG DL a;

	if(dstart==nil(DL))
		dstart = dl(sbrk(0));
	p = dend = dstart;
	dlim = a = dl(round(adr(p)+1, 512));
	brk(adr(a));
	p->flag=0;
	while(*fn) fn++;
	if(*--fn == 'g' && *--fn == '.') {
		STRING sn=fn;
		*fn = 0;
		do{fn--;}
		while(digit(*fn));
		p->y = atoi(++fn);
		*sn='.';
	}
	else{
		p->y = 0;
	}

	newdlp(BEFORE, p, 'Z', END, point(0, 0));
	newdlh(BEFORE, p, 'M', END);
	newdln(BEFORE, p, 'w', END, "\\", nil(STRING));
	newdln(BEFORE, p, 'c', END, "\\", nil(STRING));
	newdlh(BEFORE, p, 'J', END);
	newdlh(BEFORE, p, 'M', START);
	newdlh(BEFORE, p, 'B', END);
	newdln(BEFORE, p, 'L', END, "\\", nil(STRING));
	newdlp(BEFORE, p, 'Z', START, point(VERSION, 0));
	arbchip = 1;
	modified = 0;
}

/*
 * Write out display list to a file.
 *
 * fn = file name; if null, write on file last named
 */
output(fn)
	STRING fn;
{
	REG INT L;

	setname(fn);
	fileopen(filename, 1);
	L = adr(dend)-adr(dstart);

	chkwt(openfd, adr(dstart), L);
	fileclose();
}