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/* $OpenBSD: read.c,v 1.17 2015/11/19 17:50:04 tedu Exp $ */ |
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/* $NetBSD: read.c,v 1.4 1994/11/23 07:42:07 jtc Exp $ */ |
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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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#include <sys/types.h> |
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#include <sys/stat.h> |
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#include <err.h> |
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#include <stdio.h> |
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#include <stdint.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 "extern.h" |
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/* |
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* bytes -- read bytes to an offset from the end and display. |
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* |
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* This is the function that reads to a byte offset from the end of the input, |
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* storing the data in a wrap-around buffer which is then displayed. If the |
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* rflag is set, the data is displayed in lines in reverse order, and this |
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* routine has the usual nastiness of trying to find the newlines. Otherwise, |
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* it is displayed from the character closest to the beginning of the input to |
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* the end. |
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* |
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* A non-zero return means an (non-fatal) error occurred. |
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* |
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*/ |
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int |
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bytes(struct tailfile *tf, off_t off) |
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{ |
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int ch; |
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size_t len, tlen; |
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char *ep, *p, *t; |
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int wrap; |
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char *sp; |
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if (off > SIZE_MAX) |
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errx(1, "offset too large"); |
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if ((sp = p = malloc(off)) == NULL) |
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err(1, NULL); |
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for (wrap = 0, ep = p + off; (ch = getc(tf->fp)) != EOF;) { |
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*p = ch; |
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if (++p == ep) { |
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wrap = 1; |
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p = sp; |
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} |
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} |
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if (ferror(tf->fp)) { |
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ierr(tf->fname); |
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free(sp); |
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return(1); |
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} |
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if (rflag) { |
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for (t = p - 1, len = 0; t >= sp; --t, ++len) |
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if (*t == '\n' && len) { |
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WR(t + 1, len); |
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len = 0; |
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} |
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if (wrap) { |
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tlen = len; |
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for (t = ep - 1, len = 0; t >= p; --t, ++len) |
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if (*t == '\n') { |
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if (len) { |
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WR(t + 1, len); |
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len = 0; |
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} |
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if (tlen) { |
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WR(sp, tlen); |
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tlen = 0; |
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} |
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} |
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if (len) |
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WR(t + 1, len); |
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if (tlen) |
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WR(sp, tlen); |
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} |
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} else { |
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if (wrap && (len = ep - p)) |
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WR(p, len); |
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if ((len = p - sp)) |
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WR(sp, len); |
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} |
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free(sp); |
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return(0); |
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} |
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/* |
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* lines -- read lines to an offset from the end and display. |
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* |
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* This is the function that reads to a line offset from the end of the input, |
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* storing the data in an array of buffers which is then displayed. If the |
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* rflag is set, the data is displayed in lines in reverse order, and this |
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* routine has the usual nastiness of trying to find the newlines. Otherwise, |
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* it is displayed from the line closest to the beginning of the input to |
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* the end. |
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* |
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* A non-zero return means an (non-fatal) error occurred. |
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* |
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*/ |
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int |
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lines(struct tailfile *tf, off_t off) |
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{ |
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struct { |
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size_t blen; |
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size_t len; |
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char *l; |
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} *lines; |
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int ch, rc = 0; |
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char *p = NULL; |
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int wrap; |
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size_t cnt, recno, blen, newsize; |
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char *sp = NULL, *newp = NULL; |
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if (off > SIZE_MAX) |
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errx(1, "offset too large"); |
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if ((lines = calloc(off, sizeof(*lines))) == NULL) |
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err(1, NULL); |
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blen = cnt = recno = wrap = 0; |
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while ((ch = getc(tf->fp)) != EOF) { |
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if (++cnt > blen) { |
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newsize = blen + 1024; |
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if ((newp = realloc(sp, newsize)) == NULL) |
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err(1, NULL); |
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sp = newp; |
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blen = newsize; |
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p = sp + cnt - 1; |
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} |
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*p++ = ch; |
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if (ch == '\n') { |
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if (lines[recno].blen < cnt) { |
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newsize = cnt + 256; |
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if ((newp = realloc(lines[recno].l, |
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newsize)) == NULL) |
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err(1, NULL); |
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lines[recno].l = newp; |
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lines[recno].blen = newsize; |
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} |
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memcpy(lines[recno].l, sp, (lines[recno].len = cnt)); |
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cnt = 0; |
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p = sp; |
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if (++recno == off) { |
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wrap = 1; |
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recno = 0; |
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} |
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} |
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} |
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if (ferror(tf->fp)) { |
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ierr(tf->fname); |
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rc = 1; |
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goto done; |
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} |
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if (cnt) { |
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lines[recno].l = sp; |
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lines[recno].len = cnt; |
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sp = NULL; |
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if (++recno == off) { |
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wrap = 1; |
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recno = 0; |
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} |
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} |
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if (rflag) { |
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for (cnt = recno; cnt > 0; --cnt) |
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WR(lines[cnt - 1].l, lines[cnt - 1].len); |
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if (wrap) |
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for (cnt = off; cnt > recno; --cnt) |
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WR(lines[cnt - 1].l, lines[cnt - 1].len); |
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} else { |
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if (wrap) |
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for (cnt = recno; cnt < off; ++cnt) |
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WR(lines[cnt].l, lines[cnt].len); |
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for (cnt = 0; cnt < recno; ++cnt) |
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WR(lines[cnt].l, lines[cnt].len); |
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} |
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done: |
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for (cnt = 0; cnt < off; cnt++) |
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free(lines[cnt].l); |
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free(sp); |
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free(lines); |
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return(rc); |
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} |