Celestin Apprentice 2/Apprentice-Release2.iso/Source Code/C/Libraries/stdwin/Appls/dpv/dpvrestart.c

C/C++ Source or Header | 1990-09-06 | 4.1 KB | 214 lines | [TEXT/????]

/* dpv -- ditroff previewer.  Functions to restart anywhere in the file. */

#include "dpv.h"
#include "dpvmachine.h"
#include "dpvoutput.h"

typedef struct _restartinfo {
    long filepos;        /* File position for fseek */
    int pageno;        /* External page number */
    fontinfo fonts;        /* Mounted font table */
    int font, size;        /* Current font and size */
} restartinfo;

int        npages;        /* Number of pages so far */
bool        nomore;        /* Set when the last page has been seen */
restartinfo    *pagelist;    /* State needed to start each page */
int        ipage;        /* Internal page in file */
int        showpage;    /* Internal page displayed in window */
int        prevpage;    /* Last page visited (for '-' command) */
int        stoppage;    /* Internal page where to stop */
FILE        *ifile;        /* The input file */

        /* In order to avoid passing the file pointer around from
           parse() via t_page() to nextpage(), the input file is
           made available as a global variable. */

/* Initialize everything in the right order.  Tricky! */

initialize(filename, firstpage)
    char *filename;
    int firstpage;
{
    ifile= fopen(filename, "r");
    if (ifile == NULL)
        error(ABORT, "%s: cannot open", filename);
    setpageinfo(ftell(ifile), 0); /* Page 0 (== header) starts here */

    showpage= -1; /* Show no pages */
    stoppage= 1; /* Stop at beginning of page 1 */
    parse(ifile); /* Read the header */

    initoutput(filename); /* Create the window */

    showpage= 1;
    skiptopage(firstpage);
}

/* Close the file */

cleanup()
{
    fclose(ifile);
}

/* Skip n pages forward, default 1 */

forwpage(n)
    int n;
{
    if (n <= 0)
        n= 1;
    gotopage(showpage+n);
}

/* Skip n pages back, default 1 */

backpage(n)
    int n;
{
    if (n <= 0)
        n= 1;
    gotopage(showpage-n);
}

/* Go to internal page number n, and force a redraw */

gotopage(n)
    int n;
{
    int saveshowpage= showpage;
    skiptopage(n);
    if (showpage != saveshowpage)
        prevpage= saveshowpage;
    changeall();
}

/* Skip to internal page number n -- don't force a redraw */

static
skiptopage(n)
    int n;
{
    int orign= n;
    if (n <= 0)
        n= 1;
    if (n == showpage) {
        if (orign < n)
            wfleep();
        return;
    }
    if (n >= npages) {
        if (nomore) {
            n= npages-1;
            if (n == showpage) {
                wfleep();
                return;
            }
            showpage= n;
        }
        else {
            backtopage(npages-1);
            showpage= -1;
            stoppage= n;
            parse(ifile);
            showpage= npages-1;
        }
    }
    else
        showpage= n;
}

/* Draw procedure */

void
drawproc(drawwin, left, top, right, bottom)
    WINDOW *drawwin;
    int left, top, right, bottom;
{
    topdraw= top;
    botdraw= bottom;
    backtopage(showpage);
    stoppage= showpage+1;
    parse(ifile);
}

/* Record the current file position as the start of the page
   with (external) page number 'pageno'.
   Note that the 'p' command has already been consumed by the parser.
   Return < 0 if the parser can stop parsing. */

int
nextpage(pageno)
    int pageno;
{
    ++ipage;
    setpageinfo(ftell(ifile), pageno);
    if (ipage >= stoppage)
        return -1; /* Stop parsing */
    else
        return 0;
}

/* Indicate that the end of the input has been reached.
   No more new pages will be accepted. */

lastpage()
{
    nomore= TRUE;
}

/* Store info about coming page.
   Called at start of file and after 'p' command processed */

static
setpageinfo(filepos, pageno)
    long filepos;
    int pageno;
{
    if (statep != state)
        error(FATAL, "setpageinfo: {} stack not empty");
    if (ipage < npages) {
        /* We've been here already.
           Might as well check consistency. */
        /* HIRO */
    }
    else if (ipage > npages)
        error(ABORT, "setpageinfo: ipage>npages (can't happen)");
    else {
        restartinfo r;
        r.filepos= filepos;
        r.pageno= pageno;
        r.fonts= fonts;
        r.font= font;
        r.size= size;
        L_APPEND(npages, pagelist, restartinfo, r);
        if (pagelist == NULL)
            error(FATAL, "out of mem for pagelist");
    }
}

/* Position the input stream at the start of internal page i
   and restore the machine state to the state remembered for that page */

static
backtopage(i)
    int i;
{
    restartinfo *p;

    if (i < 0 || i >= npages)
        error(ABORT, "backtopage: called with wrong arg");
    p= &pagelist[i];
    if (fseek(ifile, p->filepos, 0) < 0)
        error(FATAL, "backtopage: can't fseek");
    ipage= i;
    fonts= p->fonts;
    font= p->font;
    size= p->size;
    hpos= 0;
    vpos= 0;
    statep= state;
    usefont();
}