/* $OpenBSD: input.c,v 1.2 2001/01/29 01:58:02 niklas Exp $ */ /* * Copyright (c) 1984,1985,1989,1994,1995 Mark Nudelman * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice in the documentation and/or other materials provided with * the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* * High level routines dealing with getting lines of input * from the file being viewed. * * When we speak of "lines" here, we mean PRINTABLE lines; * lines processed with respect to the screen width. * We use the term "raw line" to refer to lines simply * delimited by newlines; not processed with respect to screen width. */ #include "less.h" extern int squeeze; extern int chopline; extern int sigs; #if HILITE_SEARCH extern int hilite_search; extern int size_linebuf; #endif /* * Get the next line. * A "current" position is passed and a "new" position is returned. * The current position is the position of the first character of * a line. The new position is the position of the first character * of the NEXT line. The line obtained is the line starting at curr_pos. */ public POSITION forw_line(curr_pos) POSITION curr_pos; { POSITION new_pos; register int c; int blankline; int endline; if (curr_pos == NULL_POSITION) { null_line(); return (NULL_POSITION); } #if HILITE_SEARCH if (hilite_search == OPT_ONPLUS) prep_hilite(curr_pos, curr_pos + 3*size_linebuf); #endif if (ch_seek(curr_pos)) { null_line(); return (NULL_POSITION); } prewind(); plinenum(curr_pos); (void) ch_seek(curr_pos); c = ch_forw_get(); if (c == EOI) { null_line(); return (NULL_POSITION); } blankline = (c == '\n' || c == '\r'); for (;;) { if (ABORT_SIGS()) { null_line(); return (NULL_POSITION); } if (c == '\n' || c == EOI) { /* * End of the line. */ new_pos = ch_tell(); endline = 1; break; } /* * Append the char to the line and get the next char. */ if (pappend(c, ch_tell()-1)) { /* * The char won't fit in the line; the line * is too long to print in the screen width. * End the line here. */ if (chopline) { do { c = ch_forw_get(); } while (c != '\n' && c != EOI); new_pos = ch_tell(); endline = 1; } else { new_pos = ch_tell() - 1; endline = 0; } break; } c = ch_forw_get(); } pdone(endline); if (squeeze && blankline) { /* * This line is blank. * Skip down to the last contiguous blank line * and pretend it is the one which we are returning. */ while ((c = ch_forw_get()) == '\n' || c == '\r') if (ABORT_SIGS()) { null_line(); return (NULL_POSITION); } if (c != EOI) (void) ch_back_get(); new_pos = ch_tell(); } return (new_pos); } /* * Get the previous line. * A "current" position is passed and a "new" position is returned. * The current position is the position of the first character of * a line. The new position is the position of the first character * of the PREVIOUS line. The line obtained is the one starting at new_pos. */ public POSITION back_line(curr_pos) POSITION curr_pos; { POSITION new_pos, begin_new_pos; int c; int endline; if (curr_pos == NULL_POSITION || curr_pos <= ch_zero()) { null_line(); return (NULL_POSITION); } #if HILITE_SEARCH if (hilite_search == OPT_ONPLUS) prep_hilite((curr_pos < 3*size_linebuf) ? 0 : curr_pos - 3*size_linebuf, curr_pos); #endif if (ch_seek(curr_pos-1)) { null_line(); return (NULL_POSITION); } if (squeeze) { /* * Find out if the "current" line was blank. */ (void) ch_forw_get(); /* Skip the newline */ c = ch_forw_get(); /* First char of "current" line */ (void) ch_back_get(); /* Restore our position */ (void) ch_back_get(); if (c == '\n' || c == '\r') { /* * The "current" line was blank. * Skip over any preceding blank lines, * since we skipped them in forw_line(). */ while ((c = ch_back_get()) == '\n' || c == '\r') if (ABORT_SIGS()) { null_line(); return (NULL_POSITION); } if (c == EOI) { null_line(); return (NULL_POSITION); } (void) ch_forw_get(); } } /* * Scan backwards until we hit the beginning of the line. */ for (;;) { if (ABORT_SIGS()) { null_line(); return (NULL_POSITION); } c = ch_back_get(); if (c == '\n') { /* * This is the newline ending the previous line. * We have hit the beginning of the line. */ new_pos = ch_tell() + 1; break; } if (c == EOI) { /* * We have hit the beginning of the file. * This must be the first line in the file. * This must, of course, be the beginning of the line. */ new_pos = ch_tell(); break; } } /* * Now scan forwards from the beginning of this line. * We keep discarding "printable lines" (based on screen width) * until we reach the curr_pos. * * {{ This algorithm is pretty inefficient if the lines * are much longer than the screen width, * but I don't know of any better way. }} */ if (ch_seek(new_pos)) { null_line(); return (NULL_POSITION); } endline = 0; loop: begin_new_pos = new_pos; prewind(); plinenum(new_pos); (void) ch_seek(new_pos); do { c = ch_forw_get(); if (c == EOI || ABORT_SIGS()) { null_line(); return (NULL_POSITION); } new_pos++; if (c == '\n') { endline = 1; break; } if (pappend(c, ch_tell()-1)) { /* * Got a full printable line, but we haven't * reached our curr_pos yet. Discard the line * and start a new one. */ if (chopline) { endline = 1; break; } pdone(0); (void) ch_back_get(); new_pos--; goto loop; } } while (new_pos < curr_pos); pdone(endline); return (begin_new_pos); }