Collection of Internet/Collection of Internet.iso/msdos/lynx/source/doslynx/src/turlview.cpp

C/C++ Source or Header | 1994-10-25 | 22.2 KB | 723 lines

//      Copyright (c) 1994, University of Kansas, All Rights Reserved
//
//      Class:          TURLView
//      Include File:   turlview.h
//      Purpose:        Provide a view for an HTML document.
//      Remarks/Portability/Dependencies/Restrictions:
//              These functions in effect take the place of the original
//              gridtext functions and provide a multiple document interface
//              since each view will have its own rendered copy of the
//              original HTML image.
//              All functions are here in the same file since all will be
//              called at once.  No need to split up to help overlay manager.
//              The collection TNSCp_lines is used to hold the offset of
//              all inserted lines in the collection.
//      Revision History:
//              02-15-94        created
//              02-18-94        Possible cause for heap corruption adjusted,
//                              incorrect pointer addition.
//                              This only corrected rendered output, heap
//                              corruption still occuring.
//              02-18-94        Changed appendCharacter to accept a
//                              character instead of an signed short int.
//                              Changes split_line to reset the line
//                              split value each time it is called.
//                              No more corrupt heaps it seems.
//              02-18-94        Experiencing crashes after a large number
//                              of lines are processed, no apparent reason.
//                              Optimizing the code, it is very slow....
//              02-21-94        Beginning to see increase in speed due to
//                              minimizing the number of function calls made.
//                              Crashes resulting due to large number of
//                              lines seem to be avoided by increasing the
//                              delta argument in the TNSCollection
//                              constructor (see TURLView constructor).
//              02-22-94        Added member to class, B_avoidinfinite, to
//                              avoid infinite loops in the Double font and
//                              appendCharacter.
//        02-25-94    Modified to work with no HText styles,
//                anchors, or paragraphs in memory.
//                Always assuming that a style is active for
//                speed.
#define Uses_TProgram
#define Uses_TKeys
#include"turlview.h"
#include"tcapture.h"
#include"trace.h"
#include<string.h>

extern "C"      {
#include"htfont.h"
};

void TURLView::FormatHTML()     {
//      Purpose:        Format the HTML image file produced in gridtext.cpp
//                      into a rendered document fit for display in a view.
//      Arguments:      void
//      Return Value:   void
//      Remarks/Portability/Dependencies/Restrictions:
//              Using indexOf on the HText paragraph collection is fatal
//              for some reason.  Using the member of TextAttribute to find
//              the index.
//      Revision History:
//              02-15-94        created
//        02-25-94    modified so will not read HText image file
//                with anchors, sytles, paragraphs in memory.
//        04-06-94    Modified to compensate for WWW not calling
//                HText_endAppend.
#ifndef RELEASE
    trace("Entering FormatHTML.");
#endif // RELEASE
    //    In certain cases, the WWW library does not call
    //    HText_endAppend.  Do this for them.  We can tell if the image
    //    file still exists.
    if(HTp_HyperDoc->fsp_image != NULL)    {
#ifndef RELEASE
        trace("WWW did not call HText_endAppend.  Doing so now.");
#endif // RELEASE
        ::HText_endAppend(HTp_HyperDoc);
    }

    //      Open the HTML image file for reading.
    fsp_image = new fstream(HTp_HyperDoc->TTNp_fspname->
        getName(), ios::in | ios::nocreate | ios::binary);
    if(fsp_image == NULL)   {
        doslynxmessage("Unable to open HText image file " <<
            HTp_HyperDoc->TTNp_fspname->getName());
        B_valid = False;
        return;
    }

    //      Open the view's temporary rendered file for writing.
    fsp_temp = new fstream(TTNp_temp->getName(), ios::out | ios::trunc |
        ios::binary);
    if(fsp_temp == NULL)    {
        doslynxmessage("Unable to open HTML rendering file " <<
            TTNp_temp->getName());
        //      Close the HTML image file.
        fsp_image->close();
        delete(fsp_image);
        B_valid = False;
        return;
    }

    //      Allocate the two lines with the appropriate screen size and
    //      a safety buffer.
    L_last = (Line *)new char[sizeof(Line) + size.x + 80];
    L_new = (Line *)new char[sizeof(Line) + size.x + 80];

    if(L_last == NULL || L_new == NULL)     {
        doslynxmessage("Unable to allocate enough memory to create.");
        //      Close the files.
        fsp_image->close();
        fsp_temp->close();
        delete(fsp_image);
        delete(fsp_temp);
        B_valid = False;
        if(L_last != NULL)      {
            delete[](L_last);
        }
        if(L_new != NULL)       {
            delete[](L_new);
        }
        return;
    }
    L_last->ssi_indent = 0;
    L_last->ssi_length = 0;

    //      We are in a new paragraph and can't split anywhere.
    B_line_1 = True;
    ssi_splitAt = 0;

    //      Right now, there are no limits to the view.
    limit.y = limit.x = 0;

    //      Set member to avoid infinite loop in appendcharacter and
    //      the double font.
    B_avoidinfinite = False;

    //    There have been no spaces, but start out if so.
    B_lastSpace = True;
    //    Right now we will collapse spaces.
    B_collapseSpaces = True;

    //    No current style
    HTSp_style = NULL;

    //    If there were anchors skipped, report it.
    if(usi_skipped != 0U)    {
        doslynxmessage(usi_skipped << " anchors not created due to "
            "memory limitations.");
        usi_skipped = 0U;
    }

    //      Go through the HTML image file, calling the appropriate
    //      rendering functions for the temporary rendered file.
    char c_append;
    unsigned short int usi_checkEsc = 0;
    signed long int sli_tellg = fsp_image->tellg();
    while(fsp_image->eof() == 0)    {
        //      Get a character and act upon it.
        //      Update where we are in the file.
        c_append = fsp_image->get();
        sli_tellg++;
        if(c_append == EOF || fsp_image->bad() != 0)    {
            break;
        }
        //    Check for embedded characters.
        else if(c_append == c_Embedded)    {
            //    Is an embedded character, get the next one
            //    that tells us what type of embed it is.
            c_append = fsp_image->get();
            sli_tellg++;
            if(c_append == EOF || fsp_image->bad() != 0)    {
                break;
            }
            //      Check for styles.
            else if(c_append == c_SetStyle)    {

                auto HTStyle *HTSp_nextStyle;

                //    Changing the current style.
                //    Get the style pointer from the file.
                fsp_image->read((char *)(&HTSp_nextStyle),
                    sizeof(HTStyle *));
                sli_tellg += sizeof(HTStyle *);
                if(fsp_image->gcount() != sizeof(HTStyle *) ||
                    fsp_image->bad() != 0)    {
                    break;
                }

                //    If there was a previous style, insert
                //    blank lines.
                if(HTSp_style != NULL)    {
                    blank_lines(max(HTSp_style->
                        spaceAfter,
                        HTSp_nextStyle->spaceBefore));
                }

                //    Change to the current style.
                HTSp_style = HTSp_nextStyle;

                //    Set wether or not to collapse spaces.
                //    Will do so whenever style is not
                //    preformatted or an example.
                if(HTSp_style != NULL)    {
#ifndef RELEASE
                    trace("Current style is now " <<
                        HTSp_style->name);
#endif // RELEASE
                    if(!strcmp(HTSp_style->name,
                        "Preformatted") ||
                        !strcmp(HTSp_style->name,
                        "Example"))    {
                        B_collapseSpaces = False;
                    }
                    else    {
                        B_collapseSpaces = True;
                    }
                }
            }
            //    Check for paragraph.
            else if(c_append == c_AppendParagraph)    {

                //    Assume we have a style regardless.
                blank_lines(max(HTSp_style->spaceAfter,
                    HTSp_style->spaceBefore));
            }
            //    Check for beginning an anchor.
            else if(c_append == c_BeginAnchor)    {
                auto HTChildAnchor *HTCAp_newAnchor;

                //    Read the value of the pointer from
                //    file.
                fsp_image->read((char *)(&HTCAp_newAnchor),
                    sizeof(HTChildAnchor *));
                sli_tellg += sizeof(HTChildAnchor *);
                if(fsp_image->gcount() != sizeof(
                    HTChildAnchor *) ||
                    fsp_image->bad() != 0)    {
                    break;
                }

                //    Begin the anchor in the view.
                beginAnchor(HTCAp_newAnchor);
            }
            //    Check for ending an anchor.
            else if(c_append == c_EndAnchor)    {
                //    Simply call end anchor.
                endAnchor();
            }
        }
        //    Otherwise, should be an appendable character.
        else    {
            appendCharacter(c_append);
        }

        //      Every 1k of read information, check to see if
        //      user is trying to interrupt.
        if(usi_checkEsc++ > 1024U)     {
            //      Reset usi_checkEsc
            usi_checkEsc = 0U;

            //    Check if safe to coninue formatting due to
            //    memory limitations.  The last ??? chunks of
            //    mem will cause this to break.
            if(really_safe_pool[Stop_Rendering] == NULL)    {
                doslynxmessage("Unable to display full "
                    "document due to memory limitations.");
                break;
            }

            auto TEvent TE;

            //      Get any events in the application.
            //      Calls this to also call idle.
            TProgram::application->getEvent(TE);

            //      Interrupt on ESC key.
            if(TE.what & evKeyDown) {
                if(TE.keyDown.keyCode == kbEsc) {
                    doslynxmessage("Interrupting the "
                        "format process.");
                    doslynxmessage("Display will not "
                        "represent the full "
                        "document.");
                    //      Clear the event.
                    TProgram::application->clearEvent(TE);
                    break;
                }
            }

            //      Print a message if other events occured.
            if(TE.what != evNothing && !(TE.what & evMouseMove)
                && !(TE.what & evMouseUp))      {
                doslynxmessage("Formatting.... press ESC to "
                    "interrupt.");
            }

            //      Clear the event.
            TProgram::application->clearEvent(TE);
        }
    }

    if(fsp_image->bad() != 0)    {
        doslynxmessage("Error while reading HText image file.");
        doslynxmessage("Displaying rendering as is.");
    }

    //      Flush and release the lines.
    split_line(0);
    delete[]((char *)L_last);
    delete[]((char *)L_new);

    //      Close the files.
    fsp_image->close();
    delete(fsp_image);
    fsp_temp->close();
    delete(fsp_temp);

    //      Adjust the selected anchor to now select the anchor in
    //      the rendered file.
    if(HTCAp_2BSelected != NULL)        {
        adjustSelected();
    }

    //      Tell the view what it's new bounds are.
    //      This will set the scroll bar values.
    setLimit(limit.x, limit.y);

#ifndef RELEASE
    trace("FormatHTML returning.");
#endif // RELEASE
}

void TURLView::blank_lines(signed short int ssi_blanks) {
//      Purpose:        Insert a number of blank lines into the rendered
//                      image.
//      Arguments:      ssi_blanks      The number of blank lines to insert.
//      Return Value:   void
//      Remarks/Portability/Dependencies/Restrictions:
//              Will not count the number of previous blank lines before
//              insertion.
//      Revision History:
//              02-16-94        created

    //      Insert the appropriate number of blanks.
    //    Always atleast split one line.
    do    {
        split_line(0);
    }
    while(--ssi_blanks > 0);

    B_line_1 = True;
}

void TURLView::appendCharacter(char c_append)   {
//      Purpose:        Append a character to the output stream.
//      Arguments:      c_append        The character to append.
//      Return Value:   void
//      Remarks/Portability/Dependencies/Restrictions:
//              Assumes that any functions changing the actual last line
//              in the rendered image will update the last line member.
//      Revision History:
//              02-16-94        created
//        03-16-94    Modified to collapse spaces ' ' around all
//                types of whitespace.  For prettier output.
//                Care should be taken to not call this
//                function using spaces to align or indent
//                text, or the formatting will be collapsed.

    //    Check to see if we should ignore a space.
    if(c_append == ' ')    {
        //    Ignore it if need be.
        if(B_lastSpace == True && B_collapseSpaces == True)    {
            return;
        }

        //    Set for future condensing.
        B_lastSpace = True;

        //    Can split the line here.
        ssi_splitAt = L_last->ssi_length;
    }
    else    {
        //    Set so next time we know we have no spaces collapsed.
        B_lastSpace = False;
    }

    //      Determine the current indention of the line, if we have
    //      style.
    auto signed short int ssi_indent = 0;
    if(B_line_1 == True)    {
        ssi_indent = HTSp_style->indent1st;
    }
    else    {
        ssi_indent = HTSp_style->leftIndent;
    }

    //      Check for new lines.
    //    Set whitespace here.
    if(c_append == '\n')    {
        //    Considered a space so that following spaces are
        //    collapsed.
        B_lastSpace = True;
        split_line(0);
        B_line_1 = True;
        return;
    }
    //      Check for tabs.
    //    If so, consider whitespace.
    else if(c_append == '\t')       {
        //    Considered a space so that we collapse more spaces.
        B_lastSpace = True;
        //      The tab table.
        HTTabStop *HTTSp;
        //      Where to tab to.
        int i_target;
        //      Where we are.
        int i_here = L_last->ssi_length + L_last->ssi_indent
            + ssi_indent;

        //      If we have a tab table.
        if(HTSp_style->tabs != NULL) {
            //      Loop through the tab table until
            //      a tab will put the cursor past our
            //      current postion.
            for(HTTSp = HTSp_style->tabs; HTTSp->position <=
                i_here; HTTSp++)
            {
                //      No tab specified.
                if(HTTSp->position == 0)        {
                    split_line(0);
                    return;
                }
            }
            i_target = HTTSp->position;
        }
        //      No tab table, if in line 1 of a paragraph,
        //      use the leftIndent.
        else if(B_line_1 == True)       {
            //      If already beyond the left indent.
            if(i_here >= HTSp_style->leftIndent)     {
                split_line(0);
                return;
            }
            else    {
                i_target = HTSp_style->leftIndent;
            }
        }
        //      No tab table, not in line 1, use default mod 8
        else    {
#ifdef TABS8
            i_target = (L_last->ssi_indent + L_last->ssi_length +
                8) % 8 + HTSp_style->leftIndent;
#else
            // Just split the line.
            split_line(0);
#endif // TABS8
            return;
        }

        //      If we are past the right margin.
        if(i_target > size.x - HTSp_style->rightIndent)    {
            split_line(0);
            return;
        }
        //      Otherwise, indent the tab.
        else    {
            //      We can split the line here.
            ssi_splitAt = L_last->ssi_length;
            //      If there is nothing in the line, just
            //      increase the indentation.
            if(L_last->ssi_length == 0)     {
                L_last->ssi_indent += i_target - i_here;
            }
            //      Otherwise, space out.
            else    {
                for(; i_here < i_target; i_here++)      {
                    *((char *)L_last + sizeof(Line) +
                        L_last->ssi_length) = ' ';
                    L_last->ssi_length++;
                }
            }
            return;
        }
    }

    //      Check if beyond the screen width.
    if(ssi_indent + L_last->ssi_indent + L_last->ssi_length + HTSp_style->
        rightIndent >= size.x)
    {
        if(HTSp_style->wordWrap != 0)        {
            split_line(ssi_splitAt);
            //      We can ignore a space causing a split
            if(c_append == ' ')     {
                return;
            }
        }
        else    {
            split_line(0);
        }
    }

    //      The font of the sytle.
    HTFont HTF = HTSp_style->font;

    //      Convert NBS to a space.
    //    Do not consider as whitespace.
    if(c_append == HT_NON_BREAK_SPACE)      {
        c_append = ' ';
    }
    //      Convert the character according to font.
    else if(HTF & HT_CAPITALS)      {
        c_append = toupper(c_append);
    }

    //      Add the character to the line.
    *((char *)L_last + sizeof(Line) + L_last->ssi_length) = c_append;
    L_last->ssi_length++;

    //      On the double font, do again with a NBS
    if(HTF & HT_DOUBLE)     {
        //      Failsafe to not go infinitly recursive.
        if(B_avoidinfinite == False)    {
            B_avoidinfinite = True;
        }
        else    {
            B_avoidinfinite = False;
        }

        if(B_avoidinfinite == True)     {
            appendCharacter(HT_NON_BREAK_SPACE);
        }
    }
}

void TURLView::split_line(signed short int ssi_split)   {
//      Purpose:        Split a line at the required offset.
//      Arguments:      ssi_split       Where to split the line.
//                                      If 0, no split, just a new line.
//      Return Value:   void
//      Remarks/Portability/Dependencies/Restrictions:
//      Revision History:
//              02-16-94        created
//              02-22-98        Modified to use nothing but a TNSCollection
//                              to keep track of line offsets into the
//                              rendered file.  No memory other than the
//                              collection is allocated.

    //      Reset where last line will be split.
    ssi_splitAt = 0;

    //      Fill the members with pertinent data for the new line.
    L_new->ssi_indent = L_new->ssi_length = 0;

    //      Split at required point, skip if not needed
    if(ssi_split != 0 && L_last->ssi_length != 0)   {
        //      End the line.
        *((char *)L_last + sizeof(Line) + L_last->ssi_length) =
            '\0';
        //      Skip any space at the split point.
        char *cp;
        for(cp = (char *)L_last + sizeof(Line) + ssi_split; *cp !=
            '\0'; cp++)     {
            if(*cp != ' ')  {
                break;
            }
        }
        //      Copy the remaining information into the new line and
        //      set the members.
        strcpy(((char *)L_new + sizeof(Line)), cp);
        L_new->ssi_length = strlen(((char *)L_new + sizeof(Line)));
        L_last->ssi_length = ssi_split;
    }

    //    Take off any trailing spaces.
    while(L_last->ssi_length != 0 && *((char *)L_last + sizeof(Line) +
        L_last->ssi_length) == ' ' - 1)    {
        L_last->ssi_length--;
    }

    //      End the line.
    if(L_last->ssi_length != 0)     {
        *((char *)L_last + sizeof(Line) + L_last->ssi_length) =
            '\0';
    }

    //      Align the line according to style.
    auto int i_indent = (B_line_1 == True) ? HTSp_style->indent1st :
        HTSp_style->leftIndent;
    auto int i_spare = size.x - HTSp_style->rightIndent +
        HTSp_style->leftIndent - L_last->ssi_length;

    switch(HTSp_style->alignment)        {
    case HT_CENTER:
        L_last->ssi_indent += i_indent + i_spare / 2;
        break;
    case HT_RIGHT:
        L_last->ssi_indent += i_indent + i_spare;
        break;
    default:
        L_last->ssi_indent += i_indent;
        break;
    }

    //      We are no longer in the first line of a paragraph unless
    //      the calling function sets this otherwise.
    B_line_1 = False;

    //      Set the line collection to know where the offset of the
    //      line to be serialized is.  Using only an offset to track.
    //      Using the offset as a void * to track.
    TNSCp_lines->insert((void *)(fsp_temp->tellp()));

    //      Write the line to the rendered image file.
    fsp_temp->write((const char *)L_last, sizeof(Line) + L_last->
        ssi_length);
    //    Check for error in write, if so, must unfortunately exit.
    if(fsp_temp->bad() != 0)    {
        doslynxmessage("Error in creating rendered image.");

        //    Attemp closing the files.
        fsp_temp->close();
        fsp_image->close();

        //    Cause the application to quit.
        TEvent TE_quit;
        TE_quit.what = evMessage;
        TE_quit.message.command = cmQuit;
        TProgram::application->handleEvent(TE_quit);
    }

    //      Increment the total number of lines and maximum width.
    limit.y++;
    limit.x = max(limit.x, L_last->ssi_length + L_last->ssi_indent);

    //      We have a new last line.
    Line *L_temp = L_last;
    L_last = L_new;
    L_new = L_temp;
}

void TURLView::beginAnchor(const HTChildAnchor *HTCAp_anchor)    {
//      Purpose:        Mark the beginning of an anchor in the rendered image.
//      Arguments:      HTCAp_anchor    The child anchor to begin.
//      Return Value:   void
//      Remarks/Portability/Dependencies/Restrictions:
//              Creates a new anchor entry with offsets in the rendered file
//              pointing to the corresponding current anchor.
//      Revision History:
//              02-17-94        created

    //      Create a new anchor.
    TextAttribute *TAp_newanc = new TextAttribute(HTCAp_anchor);
    if(TAp_newanc == NULL)  {
        doslynxmessage("Unable to allocate space for new anchor.");
        B_valid = False;
        return;
    }

    //      Get the offset of the last line and it's offset by length
    //      and structure size.
    signed long int sli_where = fsp_temp->tellp() + (signed long int)
        (L_last->ssi_length + sizeof(Line));

    //      Set the beginning offset in the rendering.
    TAp_newanc->Begin(sli_where);

    //      Insert the anchor into the anchor collection.
    TNSCp_anchors->insert((void *)TAp_newanc);
}

void TURLView::endAnchor()      {
//      Purpose:        End an anchor in the rendered image.
//      Arguments:      void
//      Return Value:   void
//      Remarks/Portability/Dependencies/Restrictions:
//              Ends the last anchor in the collection at the current
//              length of the last line in the offset of the rendering.
//      Revision History:
//              02-17-94        created

    //      Get the last anchor.  Assume there is always one.
    TextAttribute *TAp_anclast = (TextAttribute *)(TNSCp_anchors->at(
        TNSCp_anchors->getCount() - 1));

    //      Get the offset of the last line and it's offset by length
    //      and structure size.
    signed long int sli_where = fsp_temp->tellp() + (signed long int)
        (L_last->ssi_length + sizeof(Line));

    //      Set the ending offset in the rendering.
    TAp_anclast->End(sli_where);
}

void TURLView::adjustSelected() {
//      Purpose:        The selected anchor originally points to the anchor
//                      owned by HText.  Convert the pointer of that anchor
//                      to the corresponding anchor owned by the view.
//      Arguments:      void
//      Return Value:   void
//      Remarks/Portability/Dependencies/Restrictions:
//      Revision History:
//              02-17-94        created

#ifndef RELEASE
    trace("Adjusting the selected anchor.");
#endif // RELEASE

    //      Find the corresponding anchor.
    //      Assume that a match will always be found.
    TextAttribute *TAp_same;
    for(TAp_same = (TextAttribute *)(TNSCp_anchors->at(0));
        TAp_same->HTCAp_anchor != HTCAp_2BSelected;
        TAp_same = (TextAttribute *)(TNSCp_anchors->at(TNSCp_anchors
        ->indexOf((void *)TAp_same) + 1)))      {
        //      Null body
    }

    //      Set the selected anchor.
    TAp_selected = TAp_same;
}