mirror of
https://github.com/freebsd/freebsd-src
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288 lines
7.1 KiB
C
288 lines
7.1 KiB
C
/*-
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* SPDX-License-Identifier: BSD-3-Clause
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*
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Edward Sze-Tyan Wang.
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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. 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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#if 0
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#ifndef lint
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static char sccsid[] = "@(#)reverse.c 8.1 (Berkeley) 6/6/93";
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#endif /* not lint */
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#endif
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#include <sys/cdefs.h>
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#include <sys/param.h>
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#include <sys/queue.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <err.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <libcasper.h>
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#include <casper/cap_fileargs.h>
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#include "extern.h"
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static void r_buf(FILE *, const char *);
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static void r_reg(FILE *, const char *, enum STYLE, off_t, struct stat *);
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/*
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* reverse -- display input in reverse order by line.
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*
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* There are six separate cases for this -- regular and non-regular
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* files by bytes, lines or the whole file.
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*
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* BYTES display N bytes
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* REG mmap the file and display the lines
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* NOREG cyclically read characters into a wrap-around buffer
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*
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* LINES display N lines
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* REG mmap the file and display the lines
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* NOREG cyclically read lines into a wrap-around array of buffers
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*
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* FILE display the entire file
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* REG mmap the file and display the lines
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* NOREG cyclically read input into a linked list of buffers
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*/
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void
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reverse(FILE *fp, const char *fn, enum STYLE style, off_t off, struct stat *sbp)
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{
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if (style != REVERSE && off == 0)
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return;
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if (S_ISREG(sbp->st_mode))
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r_reg(fp, fn, style, off, sbp);
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else
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switch(style) {
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case FBYTES:
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case RBYTES:
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bytes(fp, fn, off);
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break;
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case FLINES:
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case RLINES:
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lines(fp, fn, off);
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break;
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case REVERSE:
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r_buf(fp, fn);
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break;
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default:
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break;
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}
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}
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/*
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* r_reg -- display a regular file in reverse order by line.
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*/
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static void
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r_reg(FILE *fp, const char *fn, enum STYLE style, off_t off, struct stat *sbp)
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{
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struct mapinfo map;
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off_t curoff, size, lineend;
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int i;
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if (!(size = sbp->st_size))
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return;
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map.start = NULL;
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map.mapoff = map.maxoff = size;
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map.fd = fileno(fp);
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map.maplen = 0;
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/*
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* Last char is special, ignore whether newline or not. Note that
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* size == 0 is dealt with above, and size == 1 sets curoff to -1.
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*/
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curoff = size - 2;
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lineend = size;
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while (curoff >= 0) {
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if (curoff < map.mapoff ||
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curoff >= map.mapoff + (off_t)map.maplen) {
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if (maparound(&map, curoff) != 0) {
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ierr(fn);
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return;
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}
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}
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for (i = curoff - map.mapoff; i >= 0; i--) {
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if (style == RBYTES && --off == 0)
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break;
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if (map.start[i] == '\n')
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break;
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}
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/* `i' is either the map offset of a '\n', or -1. */
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curoff = map.mapoff + i;
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if (i < 0)
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continue;
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/* Print the line and update offsets. */
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if (mapprint(&map, curoff + 1, lineend - curoff - 1) != 0) {
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ierr(fn);
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return;
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}
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lineend = curoff + 1;
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curoff--;
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if (style == RLINES)
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off--;
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if (off == 0 && style != REVERSE) {
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/* Avoid printing anything below. */
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curoff = 0;
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break;
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}
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}
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if (curoff < 0 && mapprint(&map, 0, lineend) != 0) {
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ierr(fn);
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return;
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}
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if (map.start != NULL && munmap(map.start, map.maplen))
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ierr(fn);
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}
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#define BSZ (128 * 1024)
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typedef struct bfelem {
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TAILQ_ENTRY(bfelem) entries;
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size_t len;
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char l[BSZ];
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} bfelem_t;
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/*
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* r_buf -- display a non-regular file in reverse order by line.
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*
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* This is the function that saves the entire input, storing the data in a
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* doubly linked list of buffers and then displays them in reverse order.
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* It has the usual nastiness of trying to find the newlines, as there's no
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* guarantee that a newline occurs anywhere in the file, let alone in any
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* particular buffer. If we run out of memory, input is discarded (and the
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* user warned).
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*/
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static void
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r_buf(FILE *fp, const char *fn)
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{
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struct bfelem *tl, *first = NULL;
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size_t llen;
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char *p;
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off_t enomem = 0;
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TAILQ_HEAD(bfhead, bfelem) head;
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TAILQ_INIT(&head);
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while (!feof(fp)) {
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size_t len;
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/*
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* Allocate a new block and link it into place in a doubly
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* linked list. If out of memory, toss the LRU block and
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* keep going.
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*/
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while ((tl = malloc(sizeof(bfelem_t))) == NULL) {
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first = TAILQ_FIRST(&head);
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if (TAILQ_EMPTY(&head))
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err(1, "malloc");
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enomem += first->len;
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TAILQ_REMOVE(&head, first, entries);
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free(first);
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}
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TAILQ_INSERT_TAIL(&head, tl, entries);
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/* Fill the block with input data. */
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len = 0;
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while ((!feof(fp)) && len < BSZ) {
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p = tl->l + len;
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len += fread(p, 1, BSZ - len, fp);
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if (ferror(fp)) {
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ierr(fn);
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return;
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}
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}
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tl->len = len;
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}
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if (enomem) {
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warnx("warning: %jd bytes discarded", (intmax_t)enomem);
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rval = 1;
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}
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/*
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* Now print the lines in reverse order
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* Outline:
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* Scan backward for "\n",
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* print forward to the end of the buffers
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* free any buffers that start after the "\n" just found
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* Loop
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*/
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tl = TAILQ_LAST(&head, bfhead);
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first = TAILQ_FIRST(&head);
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while (tl != NULL) {
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struct bfelem *temp;
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for (p = tl->l + tl->len - 1, llen = 0; p >= tl->l;
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--p, ++llen) {
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int start = (tl == first && p == tl->l);
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if ((*p == '\n') || start) {
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struct bfelem *tr;
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if (llen && start && *p != '\n')
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WR(p, llen + 1);
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else if (llen) {
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WR(p + 1, llen);
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if (start && *p == '\n')
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WR(p, 1);
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}
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tr = TAILQ_NEXT(tl, entries);
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llen = 0;
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if (tr != NULL) {
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TAILQ_FOREACH_FROM_SAFE(tr, &head,
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entries, temp) {
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if (tr->len)
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WR(&tr->l, tr->len);
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TAILQ_REMOVE(&head, tr,
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entries);
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free(tr);
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}
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}
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}
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}
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tl->len = llen;
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tl = TAILQ_PREV(tl, bfhead, entries);
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}
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TAILQ_REMOVE(&head, first, entries);
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free(first);
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}
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