Mega Top 1/os2_top1.zip/os2_top1/APPS/UTILS/H-O/LESS177/MARK.C

C/C++ Source or Header | 1991-03-06 | 4KB | 238 lines

#include "less.h"
#include "position.h"

extern IFILE curr_ifile;
extern int sc_height;
extern int jump_sline;

/*
 * A mark is an ifile (input file) plus a position within the file.
 */
struct mark {
    IFILE m_ifile;
    struct scrpos m_scrpos;
};

/*
 * The table of marks.
 * Each mark is identified by a lowercase or uppercase letter.
 */
#define    NMARKS        (2*26)        /* a-z, A-Z */
static struct mark marks[NMARKS];

/*
 * Special mark for the "last mark"; addressed by the apostrophe.
 */
static struct mark lmark;

/*
 * Initialize the mark table to show no marks are set.
 */
    public void
init_mark()
{
    int i;

    for (i = 0;  i < NMARKS;  i++)
        marks[i].m_scrpos.pos = NULL_POSITION;
    lmark.m_scrpos.pos = NULL_POSITION;
}

/*
 * See if a mark letter is valid (between a and z).
 */
    static struct mark *
getumark(c)
    int c;
{
    if (c >= 'a' && c <= 'z')
        return (&marks[c-'a']);

    if (c >= 'A' && c <= 'Z')
        return (&marks[c-'A'+26]);

    error("Invalid mark letter", NULL_PARG);
    return (NULL);
}

/*
 * Get the mark structure identified by a character.
 * The mark struct may come either from the mark table
 * or may be constructed on the fly for certain characters like ^, $.
 */
    static struct mark *
getmark(c)
    int c;
{
    register struct mark *m;
    static struct mark sm;

    switch (c)
    {
    case '^':
        /*
         * Beginning of the current file.
         */
        m = &sm;
        m->m_scrpos.pos = ch_zero();
        m->m_scrpos.ln = 0;
        m->m_ifile = curr_ifile;
        break;
    case '$':
        /*
         * End of the current file.
         */
        if (ch_end_seek())
        {
            error("Cannot seek to end of file", NULL_PARG);
            return (NULL);
        }
        m = &sm;
        m->m_scrpos.pos = ch_tell();
        m->m_scrpos.ln = sc_height-1;
        m->m_ifile = curr_ifile;
        break;
    case '.':
        /*
         * Current position in the current file.
         */
        m = &sm;
        m->m_scrpos.pos = ch_tell();
        m->m_scrpos.ln = 0;
        m->m_ifile = curr_ifile;
        break;
    case '\'':
        /*
         * The "last mark".
         */
        m = &lmark;
        break;
    default:
        /*
         * Must be a user-defined mark.
         */
        m = getumark(c);
        if (m == NULL)
            break;
        if (m->m_scrpos.pos == NULL_POSITION)
        {
            error("Mark not set", NULL_PARG);
            return (NULL);
        }
        break;
    }
    return (m);
}

/*
 * Is a mark letter is invalid?
 */
    public int
badmark(c)
    int c;
{
    return (getmark(c) == NULL);
}

/*
 * Set a user-defined mark.
 */
    public void
setmark(c)
    int c;
{
    register struct mark *m;
    struct scrpos scrpos;

    m = getumark(c);
    if (m == NULL)
        return;
    get_scrpos(&scrpos);
    m->m_scrpos = scrpos;
    m->m_ifile = curr_ifile;
}

/*
 * Set lmark (the mark named by the apostrophe).
 */
    public void
lastmark()
{
    struct scrpos scrpos;

    get_scrpos(&scrpos);
    if (scrpos.pos == NULL_POSITION)
        return;
    lmark.m_scrpos = scrpos;
    lmark.m_ifile = curr_ifile;
}

/*
 * Go to a mark.
 */
    public void
gomark(c)
    int c;
{
    register struct mark *m;
    struct scrpos scrpos;

    m = getmark(c);
    if (m == NULL)
        return;

    /*
     * If we're trying to go to the lastmark and
     * it has not been set to anything yet,
     * set it to the beginning of the current file.
     */
    if (m == &lmark && m->m_scrpos.pos == NULL_POSITION)
    {
        m->m_ifile = curr_ifile;
        m->m_scrpos.pos = ch_zero();
        m->m_scrpos.ln = jump_sline;
    }

    /*
     * If we're using lmark, we must save the screen position now,
     * because if we call edit() below, lmark will change.
     * (We save the screen position even if we're not using lmark.)
     */
    scrpos = m->m_scrpos;
    if (m->m_ifile != curr_ifile)
    {
        /*
         * Not in the current file; edit the correct file.
         */
        if (edit(get_filename(m->m_ifile), 0))
            return;
    }

    jump_loc(scrpos.pos, scrpos.ln);
}

/*
 * Return the position associated with a given mark letter.
 *
 * We don't return which screen line the position
 * is associated with, but this doesn't matter much,
 * because it's always the first non-blank line on the screen.
 */
    public POSITION
markpos(c)
    int c;
{
    register struct mark *m;

    m = getmark(c);
    if (m == NULL)
        return (NULL_POSITION);

    if (m->m_ifile != curr_ifile)
    {
        error("Mark not in current file", NULL_PARG);
        return (NULL_POSITION);
    }
    return (m->m_scrpos.pos);
}