/*-
* 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.
*/
/*
* displaybytes -- 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.
*
* Non-zero return means than a (non-fatal) error occurred.
*/
int
displaybytes(FILE *fp, off_t off)
{
int ch, len, tlen;
char *ep, *p, *t;
int wrap;
char *sp;
if ((sp = p = malloc(off)) == NULL)
xerr(1, "malloc");
for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) {
*p = ch;
if (++p == ep) {
wrap = 1;
p = sp;
}
}
if (ferror(fp)) {
ierr();
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) != 0)
WR(sp, len);
}
return 0;
}
/*
* displaylines -- 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.
*
* Non-zero return means than a (non-fatal) error occurred.
*/
int
displaylines(FILE *fp, off_t off)
{
struct {
int blen;
int len;
char *l;
} *lines;
int ch;
char *p;
int blen, cnt, recno, wrap;
char *sp, *n;
p = NULL;
if ((lines = malloc(off * sizeof(*lines))) == NULL)
xerr(1, "malloc");
