c8939366a1
as controls in any case. 2) Fix bug with incorrect column position when standouts occurse 3) Fix bug when last standouted char cause clearing next line in standout
455 lines
11 KiB
C
455 lines
11 KiB
C
/*
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* Copyright (c) 1988 Mark Nudleman
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* Copyright (c) 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)ch.c 8.1 (Berkeley) 6/6/93";
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#endif /* not lint */
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/*
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* Low level character input from the input file.
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* We use these special purpose routines which optimize moving
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* both forward and backward from the current read pointer.
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*/
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#include <sys/types.h>
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#include <sys/file.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <less.h>
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int file = -1; /* File descriptor of the input file */
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/*
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* Pool of buffers holding the most recently used blocks of the input file.
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*/
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struct buf {
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struct buf *next, *prev;
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long block;
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int datasize;
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char data[BUFSIZ];
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};
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int nbufs;
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/*
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* The buffer pool is kept as a doubly-linked circular list, in order from
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* most- to least-recently used. The circular list is anchored by buf_anchor.
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*/
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#define END_OF_CHAIN ((struct buf *)&buf_anchor)
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#define buf_head buf_anchor.next
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#define buf_tail buf_anchor.prev
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static struct {
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struct buf *next, *prev;
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} buf_anchor = { END_OF_CHAIN, END_OF_CHAIN };
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extern int ispipe, cbufs, sigs;
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/*
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* Current position in file.
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* Stored as a block number and an offset into the block.
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*/
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static long ch_block;
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static int ch_offset;
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/* Length of file, needed if input is a pipe. */
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static off_t ch_fsize;
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/* Number of bytes read, if input is standard input (a pipe). */
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static off_t last_piped_pos;
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/*
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* Get the character pointed to by the read pointer. ch_get() is a macro
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* which is more efficient to call than fch_get (the function), in the usual
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* case that the block desired is at the head of the chain.
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*/
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#define ch_get() \
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((buf_head->block == ch_block && \
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ch_offset < buf_head->datasize) ? \
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buf_head->data[ch_offset] & 0xff : fch_get())
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static
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fch_get()
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{
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extern int bs_mode;
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register struct buf *bp;
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register int n, ch;
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register char *p, *t;
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off_t pos, lseek();
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/* look for a buffer holding the desired block. */
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for (bp = buf_head; bp != END_OF_CHAIN; bp = bp->next)
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if (bp->block == ch_block) {
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if (ch_offset >= bp->datasize)
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/*
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* Need more data in this buffer.
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*/
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goto read_more;
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/*
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* On a pipe, we don't sort the buffers LRU
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* because this can cause gaps in the buffers.
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* For example, suppose we've got 12 1K buffers,
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* and a 15K input stream. If we read the first 12K
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* sequentially, then jump to line 1, then jump to
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* the end, the buffers have blocks 0,4,5,6,..,14.
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* If we then jump to line 1 again and try to
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* read sequentially, we're out of luck when we
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* get to block 1 (we'd get the "pipe error" below).
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* To avoid this, we only sort buffers on a pipe
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* when we actually READ the data, not when we
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* find it already buffered.
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*/
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if (ispipe)
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return(bp->data[ch_offset] & 0xff);
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goto found;
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}
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/*
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* Block is not in a buffer. Take the least recently used buffer
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* and read the desired block into it. If the LRU buffer has data
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* in it, and input is a pipe, then try to allocate a new buffer first.
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*/
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if (ispipe && buf_tail->block != (long)(-1))
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(void)ch_addbuf(1);
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bp = buf_tail;
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bp->block = ch_block;
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bp->datasize = 0;
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read_more:
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pos = (ch_block * BUFSIZ) + bp->datasize;
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if (ispipe) {
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/*
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* The data requested should be immediately after
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* the last data read from the pipe.
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*/
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if (pos != last_piped_pos) {
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error("pipe error");
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quit();
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}
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} else
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(void)lseek(file, pos, L_SET);
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/*
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* Read the block.
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* If we read less than a full block, we just return the
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* partial block and pick up the rest next time.
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*/
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n = iread(file, &bp->data[bp->datasize], BUFSIZ - bp->datasize);
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if (n == READ_INTR)
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return (EOI);
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if (n < 0) {
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error("read error");
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quit();
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}
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if (ispipe)
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last_piped_pos += n;
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p = &bp->data[bp->datasize];
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bp->datasize += n;
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/*
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* Set an EOI marker in the buffered data itself. Then ensure the
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* data is "clean": there are no extra EOI chars in the data and
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* that the "meta" bit (the 0200 bit) is reset in each char;
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* also translate \r\n sequences to \n if -u flag not set.
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*/
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if (n == 0) {
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ch_fsize = pos;
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bp->data[bp->datasize++] = EOI;
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}
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if (bs_mode) {
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for (p = &bp->data[bp->datasize]; --n >= 0;) {
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*--p;
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if (*p == EOI)
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*p = 0200;
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}
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}
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else {
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for (t = p; --n >= 0; ++p) {
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ch = *p;
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if (ch == '\r' && n && p[1] == '\n') {
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++p;
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*t++ = '\n';
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}
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else
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*t++ = (ch == EOI) ? 0200 : ch;
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}
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if (p != t) {
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bp->datasize -= p - t;
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if (ispipe)
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last_piped_pos -= p - t;
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}
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}
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found:
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if (buf_head != bp) {
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/*
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* Move the buffer to the head of the buffer chain.
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* This orders the buffer chain, most- to least-recently used.
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*/
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bp->next->prev = bp->prev;
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bp->prev->next = bp->next;
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bp->next = buf_head;
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bp->prev = END_OF_CHAIN;
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buf_head->prev = bp;
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buf_head = bp;
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}
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if (ch_offset >= bp->datasize)
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/*
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* After all that, we still don't have enough data.
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* Go back and try again.
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*/
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goto read_more;
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return(bp->data[ch_offset] & 0xff);
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}
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/*
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* Determine if a specific block is currently in one of the buffers.
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*/
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static
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buffered(block)
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long block;
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{
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register struct buf *bp;
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for (bp = buf_head; bp != END_OF_CHAIN; bp = bp->next)
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if (bp->block == block)
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return(1);
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return(0);
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}
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/*
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* Seek to a specified position in the file.
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* Return 0 if successful, non-zero if can't seek there.
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*/
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ch_seek(pos)
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register off_t pos;
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{
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long new_block;
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new_block = pos / BUFSIZ;
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if (!ispipe || pos == last_piped_pos || buffered(new_block)) {
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/*
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* Set read pointer.
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*/
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ch_block = new_block;
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ch_offset = pos % BUFSIZ;
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return(0);
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}
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return(1);
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}
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/*
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* Seek to the end of the file.
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*/
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ch_end_seek()
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{
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off_t ch_length();
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if (!ispipe)
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return(ch_seek(ch_length()));
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/*
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* Do it the slow way: read till end of data.
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*/
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while (ch_forw_get() != EOI)
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if (sigs)
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return(1);
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return(0);
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}
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/*
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* Seek to the beginning of the file, or as close to it as we can get.
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* We may not be able to seek there if input is a pipe and the
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* beginning of the pipe is no longer buffered.
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*/
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ch_beg_seek()
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{
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register struct buf *bp, *firstbp;
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/*
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* Try a plain ch_seek first.
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*/
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if (ch_seek((off_t)0) == 0)
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return(0);
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/*
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* Can't get to position 0.
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* Look thru the buffers for the one closest to position 0.
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*/
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firstbp = bp = buf_head;
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if (bp == END_OF_CHAIN)
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return(1);
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while ((bp = bp->next) != END_OF_CHAIN)
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if (bp->block < firstbp->block)
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firstbp = bp;
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ch_block = firstbp->block;
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ch_offset = 0;
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return(0);
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}
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/*
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* Return the length of the file, if known.
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*/
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off_t
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ch_length()
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{
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off_t lseek();
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if (ispipe)
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return(ch_fsize);
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return((off_t)(lseek(file, (off_t)0, L_XTND)));
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}
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/*
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* Return the current position in the file.
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*/
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off_t
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ch_tell()
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{
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return(ch_block * BUFSIZ + ch_offset);
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}
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/*
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* Get the current char and post-increment the read pointer.
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*/
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ch_forw_get()
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{
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register int c;
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c = ch_get();
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if (c != EOI && ++ch_offset >= BUFSIZ) {
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ch_offset = 0;
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++ch_block;
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}
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return(c);
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}
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/*
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* Pre-decrement the read pointer and get the new current char.
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*/
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ch_back_get()
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{
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if (--ch_offset < 0) {
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if (ch_block <= 0 || (ispipe && !buffered(ch_block-1))) {
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ch_offset = 0;
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return(EOI);
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}
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ch_offset = BUFSIZ - 1;
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ch_block--;
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}
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return(ch_get());
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}
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/*
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* Allocate buffers.
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* Caller wants us to have a total of at least want_nbufs buffers.
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* keep==1 means keep the data in the current buffers;
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* otherwise discard the old data.
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*/
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ch_init(want_nbufs, keep)
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int want_nbufs;
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int keep;
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{
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register struct buf *bp;
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char message[80];
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cbufs = nbufs;
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if (nbufs < want_nbufs && ch_addbuf(want_nbufs - nbufs)) {
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/*
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* Cannot allocate enough buffers.
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* If we don't have ANY, then quit.
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* Otherwise, just report the error and return.
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*/
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(void)sprintf(message, "cannot allocate %d buffers",
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want_nbufs - nbufs);
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error(message);
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if (nbufs == 0)
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quit();
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return;
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}
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if (keep)
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return;
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/*
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* We don't want to keep the old data,
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* so initialize all the buffers now.
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*/
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for (bp = buf_head; bp != END_OF_CHAIN; bp = bp->next)
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bp->block = (long)(-1);
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last_piped_pos = (off_t)0;
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ch_fsize = NULL_POSITION;
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(void)ch_seek((off_t)0);
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}
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/*
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* Allocate some new buffers.
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* The buffers are added to the tail of the buffer chain.
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*/
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ch_addbuf(nnew)
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int nnew;
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{
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register struct buf *bp;
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register struct buf *newbufs;
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char *calloc();
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/*
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* We don't have enough buffers.
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* Allocate some new ones.
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*/
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newbufs = (struct buf *)calloc((u_int)nnew, sizeof(struct buf));
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if (newbufs == NULL)
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return(1);
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/*
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* Initialize the new buffers and link them together.
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* Link them all onto the tail of the buffer list.
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*/
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nbufs += nnew;
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cbufs = nbufs;
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for (bp = &newbufs[0]; bp < &newbufs[nnew]; bp++) {
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bp->next = bp + 1;
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bp->prev = bp - 1;
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bp->block = (long)(-1);
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}
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newbufs[nnew-1].next = END_OF_CHAIN;
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newbufs[0].prev = buf_tail;
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buf_tail->next = &newbufs[0];
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buf_tail = &newbufs[nnew-1];
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return(0);
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}
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