1 files changed, 77 insertions, 0 deletions
diff --git a/usr/gzip/unzip.c b/usr/gzip/unzip.c
new file mode 100644
index 0000000..c8e14a3
--- /dev/null
+++ b/usr/gzip/unzip.c
@@ -0,0 +1,77 @@
+/* unzip.c -- decompress files in gzip or pkzip format.
+ * Copyright (C) 1992-1993 Jean-loup Gailly
+ * This is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License, see the file COPYING.
+ *
+ * The code in this file is derived from the file funzip.c written
+ * and put in the public domain by Mark Adler.
+ */
+
+/*
+   This version can extract files in gzip format.
+   Only the first entry is extracted, and it has to be
+   either deflated or stored.
+ */
+
+#ifdef RCSID
+static char rcsid[] = "$Id: unzip.c,v 1.1 2002/08/18 00:59:21 hpa Exp $";
+#endif
+
+#include "tailor.h"
+#include "gzip.h"
+
+/* ===========================================================================
+ * Unzip in to out.  This routine works on gzip files only.
+ *
+ * IN assertions: the buffer inbuf contains already the beginning of
+ *   the compressed data, from offsets inptr to insize-1 included.
+ *   The magic header has already been checked. The output buffer is cleared.
+ */
+int unzip(in, out)
+    int in, out;   /* input and output file descriptors */
+{
+    ulg orig_crc = 0;       /* original crc */
+    ulg orig_len = 0;       /* original uncompressed length */
+    int n;
+    uch buf[8];        /* extended local header */
+
+    ifd = in;
+    ofd = out;
+
+    updcrc(NULL, 0);           /* initialize crc */
+
+    /* Decompress */
+    if (method == DEFLATED)  {
+
+	int res = inflate();
+
+	if (res == 3) {
+	    error("out of memory");
+	} else if (res != 0) {
+	    error("invalid compressed data--format violated");
+	}
+
+    } else {
+	error("internal error, invalid method");
+    }
+
+    /* Get the crc and original length */
+    /* crc32  (see algorithm.doc)
+     * uncompressed input size modulo 2^32
+     */
+    for (n = 0; n < 8; n++) {
+	buf[n] = (uch)get_byte(); /* may cause an error if EOF */
+    }
+    orig_crc = LG(buf);
+    orig_len = LG(buf+4);
+
+    /* Validate decompression */
+    if (orig_crc != updcrc(outbuf, 0)) {
+	error("invalid compressed data--crc error");
+    }
+    if (orig_len != (ulg)bytes_out) {
+	error("invalid compressed data--length error");
+    }
+
+    return OK;
+}