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IABSD.fr/src/usr.bin/less/jump.c
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- usr.bin/less/jump.c
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/* * Copyright (C) 1984-2012 Mark Nudelman * Modified for use with illumos by Garrett D'Amore. * Copyright 2014 Garrett D'Amore <garrett@damore.org> * * 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, 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. */ void jump_forw(void) { off_t pos; off_t end_pos; if (ch_end_seek()) { error("Cannot seek to end of file", NULL); 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 == -1) { jump_loc(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. */ void jump_back(off_t linenum) { off_t 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 != -1 && 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); } else { parg.p_linenum = linenum; error("Cannot seek to line number %n", &parg); } } /* * Repaint the screen. */ void repaint(void) { 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. */ void jump_percent(int percent, long fraction) { off_t pos, len; /* * Determine the position in the file * (the specified percentage of the file's length). */ if ((len = ch_length()) == -1) { ierror("Determining length of file", NULL); ch_end_seek(); } if ((len = ch_length()) == -1) { error("Don't know length of file", NULL); 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. */ void jump_line_loc(off_t 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. */ void jump_loc(off_t pos, int sline) { int nline; off_t tpos; off_t 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 (show_attn) repaint_hilite(1); return; } /* * Line is not on screen. * Seek to the desired location. */ if (ch_seek(pos)) { error("Cannot seek to that file position", NULL); return; } /* * See if the desired line is before or after * the currently displayed screen. */ tpos = position(TOP); bpos = position(BOTTOM_PLUS_ONE); if (tpos == -1 || 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 != -1 && 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 (show_attn) repaint_hilite(1); return; } pos = back_line(pos); if (pos == -1) { /* * 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 == -1) { /* * 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 (show_attn) repaint_hilite(1); return; } } lastmark(); if (!top_scroll) do_clear(); else home(); screen_trashed = 0; add_back_pos(pos); back(sc_height-1, pos, 1, 0); } }