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-rw-r--r--tools/cpio/src/ib_seek.c53
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diff --git a/tools/cpio/src/ib_seek.c b/tools/cpio/src/ib_seek.c
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+++ b/tools/cpio/src/ib_seek.c
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+/*
+ * Copyright (c) 2003 Gunnar Ritter
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute
+ * it freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software
+ * in a product, an acknowledgment in the product documentation would be
+ * appreciated but is not required.
+ *
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ *
+ * 3. This notice may not be removed or altered from any source distribution.
+ */
+/* Sccsid @(#)ib_seek.c 1.4 (gritter) 5/8/03 */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+
+#include "iblok.h"
+
+off_t
+ib_seek(struct iblok *ip, off_t off, int whence)
+{
+ if (whence == SEEK_CUR) {
+ off = ip->ib_endoff - (ip->ib_end - ip->ib_cur);
+ whence = SEEK_SET;
+ }
+ if (ip->ib_seekable && whence == SEEK_SET && ip->ib_cur && ip->ib_end &&
+ off < ip->ib_endoff &&
+ off >= ip->ib_endoff - (ip->ib_end - ip->ib_blk)) {
+ ip->ib_cur = ip->ib_end - (ip->ib_endoff - off);
+ return off;
+ }
+ if ((off = lseek(ip->ib_fd, off, whence)) == (off_t)-1)
+ return -1;
+ ip->ib_cur = ip->ib_end = NULL;
+ ip->ib_endoff = off;
+ ip->ib_seekable = 1;
+ return off;
+}