269 lines
6.5 KiB
C
269 lines
6.5 KiB
C
/* $NetBSD: reverse.c,v 1.23 2011/09/03 10:59:11 christos Exp $ */
|
|
|
|
/*-
|
|
* Copyright (c) 1991, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* Edward Sze-Tyan Wang.
|
|
*
|
|
* 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, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
#ifndef lint
|
|
#if 0
|
|
static char sccsid[] = "@(#)reverse.c 8.1 (Berkeley) 6/6/93";
|
|
#endif
|
|
__RCSID("$NetBSD: reverse.c,v 1.23 2011/09/03 10:59:11 christos Exp $");
|
|
#endif /* not lint */
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/mman.h>
|
|
|
|
#include <limits.h>
|
|
#include <errno.h>
|
|
#include <unistd.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include "extern.h"
|
|
|
|
static void r_buf(FILE *);
|
|
static void r_reg(FILE *, enum STYLE, off_t, struct stat *);
|
|
|
|
/*
|
|
* reverse -- display input in reverse order by line.
|
|
*
|
|
* There are six separate cases for this -- regular and non-regular
|
|
* files by bytes, lines or the whole file.
|
|
*
|
|
* BYTES display N bytes
|
|
* REG mmap the file and display the lines
|
|
* NOREG cyclically read characters into a wrap-around buffer
|
|
*
|
|
* LINES display N lines
|
|
* REG mmap the file and display the lines
|
|
* NOREG cyclically read lines into a wrap-around array of buffers
|
|
*
|
|
* FILE display the entire file
|
|
* REG mmap the file and display the lines
|
|
* NOREG cyclically read input into a linked list of buffers
|
|
*/
|
|
void
|
|
reverse(FILE *fp, enum STYLE style, off_t off, struct stat *sbp)
|
|
{
|
|
if (style != REVERSE && off == 0)
|
|
return;
|
|
|
|
if (S_ISREG(sbp->st_mode))
|
|
r_reg(fp, style, off, sbp);
|
|
else
|
|
switch(style) {
|
|
case FBYTES:
|
|
case RBYTES:
|
|
(void)displaybytes(fp, off);
|
|
break;
|
|
case FLINES:
|
|
case RLINES:
|
|
(void)displaylines(fp, off);
|
|
break;
|
|
case REVERSE:
|
|
r_buf(fp);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* r_reg -- display a regular file in reverse order by line.
|
|
*/
|
|
static void
|
|
r_reg(FILE *fp, enum STYLE style, off_t off, struct stat *sbp)
|
|
{
|
|
off_t size;
|
|
int llen;
|
|
char *p;
|
|
char *start;
|
|
|
|
if (!(size = sbp->st_size))
|
|
return;
|
|
|
|
if ((uint64_t)size > SIZE_T_MAX) {
|
|
/* XXX: need a cleaner way to check this on amd64 */
|
|
errno = EFBIG;
|
|
xerr(0, "%s", fname);
|
|
return;
|
|
}
|
|
|
|
if ((start = mmap(NULL, (size_t)size, PROT_READ,
|
|
MAP_FILE|MAP_SHARED, fileno(fp), (off_t)0)) == MAP_FAILED) {
|
|
xerr(0, "%s", fname);
|
|
return;
|
|
}
|
|
p = start + size - 1;
|
|
|
|
if (style == RBYTES && off < size)
|
|
size = off;
|
|
|
|
/* Last char is special, ignore whether newline or not. */
|
|
for (llen = 1; --size; ++llen)
|
|
if (*--p == '\n') {
|
|
WR(p + 1, llen);
|
|
llen = 0;
|
|
if (style == RLINES && !--off) {
|
|
++p;
|
|
break;
|
|
}
|
|
}
|
|
if (llen)
|
|
WR(p, llen);
|
|
if (munmap(start, (size_t)sbp->st_size))
|
|
xerr(0, "%s", fname);
|
|
}
|
|
|
|
typedef struct bf {
|
|
struct bf *next;
|
|
struct bf *prev;
|
|
int len;
|
|
char *l;
|
|
} BF;
|
|
|
|
/*
|
|
* r_buf -- display a non-regular file in reverse order by line.
|
|
*
|
|
* This is the function that saves the entire input, storing the data in a
|
|
* doubly linked list of buffers and then displays them in reverse order.
|
|
* It has the usual nastiness of trying to find the newlines, as there's no
|
|
* guarantee that a newline occurs anywhere in the file, let alone in any
|
|
* particular buffer. If we run out of memory, input is discarded (and the
|
|
* user warned).
|
|
*/
|
|
static void
|
|
r_buf(FILE *fp)
|
|
{
|
|
BF *mark, *tl, *tr;
|
|
int ch, len, llen;
|
|
char *p;
|
|
off_t enomem;
|
|
|
|
#define BSZ (128 * 1024)
|
|
tl = NULL;
|
|
for (mark = NULL, enomem = 0;;) {
|
|
/*
|
|
* Allocate a new block and link it into place in a doubly
|
|
* linked list. If out of memory, toss the LRU block and
|
|
* keep going.
|
|
*/
|
|
if (enomem) {
|
|
if (!mark) {
|
|
errno = ENOMEM;
|
|
xerr(1, NULL);
|
|
}
|
|
tl = tl->next;
|
|
enomem += tl->len;
|
|
} else if ((tl = malloc(sizeof(*tl))) == NULL ||
|
|
(tl->l = malloc(BSZ)) == NULL) {
|
|
if (tl)
|
|
free(tl);
|
|
if (!mark) {
|
|
errno = ENOMEM;
|
|
xerr(1, NULL);
|
|
}
|
|
tl = mark;
|
|
enomem += tl->len;
|
|
} else if (mark) {
|
|
tl->next = mark;
|
|
tl->prev = mark->prev;
|
|
mark->prev->next = tl;
|
|
mark->prev = tl;
|
|
} else {
|
|
mark = tl;
|
|
mark->next = mark->prev = mark;
|
|
}
|
|
|
|
/* Fill the block with input data. */
|
|
ch = 0;
|
|
for (p = tl->l, len = 0;
|
|
len < BSZ && (ch = getc(fp)) != EOF; ++len)
|
|
*p++ = ch;
|
|
|
|
/*
|
|
* If no input data for this block and we tossed some data,
|
|
* recover it.
|
|
*/
|
|
if (!len) {
|
|
if (enomem)
|
|
enomem -= tl->len;
|
|
tl = tl->prev;
|
|
break;
|
|
}
|
|
|
|
tl->len = len;
|
|
if (ch == EOF)
|
|
break;
|
|
}
|
|
|
|
if (enomem) {
|
|
xerrx(0, "Warning: %lld bytes discarded", (long long)enomem);
|
|
}
|
|
|
|
/*
|
|
* Step through the blocks in the reverse order read. The last char
|
|
* is special, ignore whether newline or not.
|
|
*/
|
|
for (mark = tl;;) {
|
|
for (p = tl->l + (len = tl->len) - 1, llen = 0; len--;
|
|
--p, ++llen)
|
|
if (*p == '\n') {
|
|
if (llen) {
|
|
WR(p + 1, llen);
|
|
llen = 0;
|
|
}
|
|
if (tl == mark)
|
|
continue;
|
|
for (tr = tl->next; tr->len; tr = tr->next) {
|
|
WR(tr->l, tr->len);
|
|
tr->len = 0;
|
|
if (tr == mark)
|
|
break;
|
|
}
|
|
}
|
|
tl->len = llen;
|
|
if ((tl = tl->prev) == mark)
|
|
break;
|
|
}
|
|
tl = tl->next;
|
|
if (tl->len) {
|
|
WR(tl->l, tl->len);
|
|
tl->len = 0;
|
|
}
|
|
while ((tl = tl->next)->len) {
|
|
WR(tl->l, tl->len);
|
|
tl->len = 0;
|
|
}
|
|
}
|