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/* $OpenBSD: read.c,v 1.13 2008/06/02 06:01:15 otto Exp $ */
/* $NetBSD: read.c,v 1.4 1994/11/23 07:42:07 jtc 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.
*/
#ifndef lint
#if 0
static char sccsid[] = "@(#)read.c 8.1 (Berkeley) 6/6/93";
#endif
static char rcsid[] = "$OpenBSD: read.c,v 1.13 2008/06/02 06:01:15 otto Exp $";
#endif /* not lint */
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/limits.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "extern.h"
/*
* bytes -- read bytes to an offset from the end and display.
*
* This is the function that reads to a byte offset from the end of the input,
* storing the data in a wrap-around buffer which is then displayed. If the
* rflag is set, the data is displayed in lines in reverse order, and this
* routine has the usual nastiness of trying to find the newlines. Otherwise,
* it is displayed from the character closest to the beginning of the input to
* the end.
*
* A non-zero return means an (non-fatal) error occurred.
*
*/
int
bytes(FILE *fp, off_t off)
{
int ch;
size_t len, tlen;
char *ep, *p, *t;
int wrap;
char *sp;
if (off > SIZE_T_MAX)
errx(1, "offset too large");
if ((sp = p = malloc(off)) == NULL)
err(1, NULL);
for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) {
*p = ch;
if (++p == ep) {
wrap = 1;
p = sp;
}
}
if (ferror(fp)) {
ierr();
free(sp);
return(1);
}
if (rflag) {
for (t = p - 1, len = 0; t >= sp; --t, ++len)
if (*t == '\n' && len) {
WR(t + 1, len);
len = 0;
}
if (wrap) {
tlen = len;
for (t = ep - 1, len = 0; t >= p; --t, ++len)
if (*t == '\n') {
if (len) {
WR(t + 1, len);
len = 0;
}
if (tlen) {
WR(sp, tlen);
tlen = 0;
}
}
if (len)
WR(t + 1, len);
if (tlen)
WR(sp, tlen);
}
} else {
if (wrap && (len = ep - p))
WR(p, len);
if ((len = p - sp))
WR(sp, len);
}
free(sp);
return(0);
}
/*
* lines -- read lines to an offset from the end and display.
*
* This is the function that reads to a line offset from the end of the input,
* storing the data in an array of buffers which is then displayed. If the
* rflag is set, the data is displayed in lines in reverse order, and this
* routine has the usual nastiness of trying to find the newlines. Otherwise,
* it is displayed from the line closest to the beginning of the input to
* the end.
*
* A non-zero return means an (non-fatal) error occurred.
*
*/
int
lines(FILE *fp, off_t off)
{
struct {
size_t blen;
size_t len;
char *l;
} *lines;
int ch, rc = 0;
char *p = NULL;
int wrap;
size_t cnt, recno, blen, newsize;
char *sp = NULL, *newp = NULL;
if (off > SIZE_T_MAX)
errx(1, "offset too large");
if ((lines = calloc(off, sizeof(*lines))) == NULL)
err(1, NULL);
blen = cnt = recno = wrap = 0;
while ((ch = getc(fp)) != EOF) {
if (++cnt > blen) {
newsize = blen + 1024;
if ((newp = realloc(sp, newsize)) == NULL)
err(1, NULL);
sp = newp;
blen = newsize;
p = sp + cnt - 1;
}
*p++ = ch;
if (ch == '\n') {
if (lines[recno].blen < cnt) {
newsize = cnt + 256;
if ((newp = realloc(lines[recno].l,
newsize)) == NULL)
err(1, NULL);
lines[recno].l = newp;
lines[recno].blen = newsize;
}
memcpy(lines[recno].l, sp, (lines[recno].len = cnt));
cnt = 0;
p = sp;
if (++recno == off) {
wrap = 1;
recno = 0;
}
}
}
if (ferror(fp)) {
ierr();
rc = 1;
goto done;
}
if (cnt) {
lines[recno].l = sp;
lines[recno].len = cnt;
sp = NULL;
if (++recno == off) {
wrap = 1;
recno = 0;
}
}
if (rflag) {
for (cnt = recno; cnt > 0; --cnt)
WR(lines[cnt - 1].l, lines[cnt - 1].len);
if (wrap)
for (cnt = off; cnt > recno; --cnt)
WR(lines[cnt - 1].l, lines[cnt - 1].len);
} else {
if (wrap)
for (cnt = recno; cnt < off; ++cnt)
WR(lines[cnt].l, lines[cnt].len);
for (cnt = 0; cnt < recno; ++cnt)
WR(lines[cnt].l, lines[cnt].len);
}
done:
for (cnt = 0; cnt < off; cnt++)
free(lines[cnt].l);
free(sp);
free(lines);
return(rc);
}
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