--- /dev/null
+/*
+ * Copyright (C) 1984-2011 Mark Nudelman
+ *
+ * You may distribute under the terms of either the GNU General Public
+ * License or the Less License, as specified in the README file.
+ *
+ * For more information about less, or for information on how to
+ * contact the author, see the README file.
+ */
+
+
+/*
+ * Routines which jump to a new location in the file.
+ */
+
+#include "less.h"
+#include "position.h"
+
+extern int jump_sline;
+extern int squished;
+extern int screen_trashed;
+extern int sc_width, sc_height;
+extern int show_attn;
+extern int top_scroll;
+
+/*
+ * Jump to the end of the file.
+ */
+ public void
+jump_forw()
+{
+ POSITION pos;
+ POSITION end_pos;
+
+ if (ch_end_seek())
+ {
+ error("Cannot seek to end of file", NULL_PARG);
+ return;
+ }
+ /*
+ * Note; lastmark will be called later by jump_loc, but it fails
+ * because the position table has been cleared by pos_clear below.
+ * So call it here before calling pos_clear.
+ */
+ lastmark();
+ /*
+ * Position the last line in the file at the last screen line.
+ * Go back one line from the end of the file
+ * to get to the beginning of the last line.
+ */
+ pos_clear();
+ end_pos = ch_tell();
+ pos = back_line(end_pos);
+ if (pos == NULL_POSITION)
+ jump_loc((POSITION)0, sc_height-1);
+ else
+ {
+ jump_loc(pos, sc_height-1);
+ if (position(sc_height-1) != end_pos)
+ repaint();
+ }
+}
+
+/*
+ * Jump to line n in the file.
+ */
+ public void
+jump_back(linenum)
+ LINENUM linenum;
+{
+ POSITION pos;
+ PARG parg;
+
+ /*
+ * Find the position of the specified line.
+ * If we can seek there, just jump to it.
+ * If we can't seek, but we're trying to go to line number 1,
+ * use ch_beg_seek() to get as close as we can.
+ */
+ pos = find_pos(linenum);
+ if (pos != NULL_POSITION && ch_seek(pos) == 0)
+ {
+ if (show_attn)
+ set_attnpos(pos);
+ jump_loc(pos, jump_sline);
+ } else if (linenum <= 1 && ch_beg_seek() == 0)
+ {
+ jump_loc(ch_tell(), jump_sline);
+ error("Cannot seek to beginning of file", NULL_PARG);
+ } else
+ {
+ parg.p_linenum = linenum;
+ error("Cannot seek to line number %n", &parg);
+ }
+}
+
+/*
+ * Repaint the screen.
+ */
+ public void
+repaint()
+{
+ struct scrpos scrpos;
+ /*
+ * Start at the line currently at the top of the screen
+ * and redisplay the screen.
+ */
+ get_scrpos(&scrpos);
+ pos_clear();
+ jump_loc(scrpos.pos, scrpos.ln);
+}
+
+/*
+ * Jump to a specified percentage into the file.
+ */
+ public void
+jump_percent(percent, fraction)
+ int percent;
+ long fraction;
+{
+ POSITION pos, len;
+
+ /*
+ * Determine the position in the file
+ * (the specified percentage of the file's length).
+ */
+ if ((len = ch_length()) == NULL_POSITION)
+ {
+ ierror("Determining length of file", NULL_PARG);
+ ch_end_seek();
+ }
+ if ((len = ch_length()) == NULL_POSITION)
+ {
+ error("Don't know length of file", NULL_PARG);
+ return;
+ }
+ pos = percent_pos(len, percent, fraction);
+ if (pos >= len)
+ pos = len-1;
+
+ jump_line_loc(pos, jump_sline);
+}
+
+/*
+ * Jump to a specified position in the file.
+ * Like jump_loc, but the position need not be
+ * the first character in a line.
+ */
+ public void
+jump_line_loc(pos, sline)
+ POSITION pos;
+ int sline;
+{
+ int c;
+
+ if (ch_seek(pos) == 0)
+ {
+ /*
+ * Back up to the beginning of the line.
+ */
+ while ((c = ch_back_get()) != '\n' && c != EOI)
+ ;
+ if (c == '\n')
+ (void) ch_forw_get();
+ pos = ch_tell();
+ }
+ if (show_attn)
+ set_attnpos(pos);
+ jump_loc(pos, sline);
+}
+
+/*
+ * Jump to a specified position in the file.
+ * The position must be the first character in a line.
+ * Place the target line on a specified line on the screen.
+ */
+ public void
+jump_loc(pos, sline)
+ POSITION pos;
+ int sline;
+{
+ register int nline;
+ POSITION tpos;
+ POSITION bpos;
+
+ /*
+ * Normalize sline.
+ */
+ sline = adjsline(sline);
+
+ if ((nline = onscreen(pos)) >= 0)
+ {
+ /*
+ * The line is currently displayed.
+ * Just scroll there.
+ */
+ nline -= sline;
+ if (nline > 0)
+ forw(nline, position(BOTTOM_PLUS_ONE), 1, 0, 0);
+ else
+ back(-nline, position(TOP), 1, 0);
+#if HILITE_SEARCH
+ if (show_attn)
+ repaint_hilite(1);
+#endif
+ return;
+ }
+
+ /*
+ * Line is not on screen.
+ * Seek to the desired location.
+ */
+ if (ch_seek(pos))
+ {
+ error("Cannot seek to that file position", NULL_PARG);
+ return;
+ }
+
+ /*
+ * See if the desired line is before or after
+ * the currently displayed screen.
+ */
+ tpos = position(TOP);
+ bpos = position(BOTTOM_PLUS_ONE);
+ if (tpos == NULL_POSITION || pos >= tpos)
+ {
+ /*
+ * The desired line is after the current screen.
+ * Move back in the file far enough so that we can
+ * call forw() and put the desired line at the
+ * sline-th line on the screen.
+ */
+ for (nline = 0; nline < sline; nline++)
+ {
+ if (bpos != NULL_POSITION && pos <= bpos)
+ {
+ /*
+ * Surprise! The desired line is
+ * close enough to the current screen
+ * that we can just scroll there after all.
+ */
+ forw(sc_height-sline+nline-1, bpos, 1, 0, 0);
+#if HILITE_SEARCH
+ if (show_attn)
+ repaint_hilite(1);
+#endif
+ return;
+ }
+ pos = back_line(pos);
+ if (pos == NULL_POSITION)
+ {
+ /*
+ * Oops. Ran into the beginning of the file.
+ * Exit the loop here and rely on forw()
+ * below to draw the required number of
+ * blank lines at the top of the screen.
+ */
+ break;
+ }
+ }
+ lastmark();
+ squished = 0;
+ screen_trashed = 0;
+ forw(sc_height-1, pos, 1, 0, sline-nline);
+ } else
+ {
+ /*
+ * The desired line is before the current screen.
+ * Move forward in the file far enough so that we
+ * can call back() and put the desired line at the
+ * sline-th line on the screen.
+ */
+ for (nline = sline; nline < sc_height - 1; nline++)
+ {
+ pos = forw_line(pos);
+ if (pos == NULL_POSITION)
+ {
+ /*
+ * Ran into end of file.
+ * This shouldn't normally happen,
+ * but may if there is some kind of read error.
+ */
+ break;
+ }
+ if (pos >= tpos)
+ {
+ /*
+ * Surprise! The desired line is
+ * close enough to the current screen
+ * that we can just scroll there after all.
+ */
+ back(nline+1, tpos, 1, 0);
+#if HILITE_SEARCH
+ if (show_attn)
+ repaint_hilite(1);
+#endif
+ return;
+ }
+ }
+ lastmark();
+ if (!top_scroll)
+ clear();
+ else
+ home();
+ screen_trashed = 0;
+ add_back_pos(pos);
+ back(sc_height-1, pos, 1, 0);
+ }
+}
projects / apitrace / blobdiff