feat: add gzip and new headers

1 files changed, 76 insertions, 0 deletions

diff --git a/bin/gzip/unzip.c b/bin/gzip/unzip.c
new file mode 100644
index 00000000..72855f8b
--- /dev/null
+++ b/bin/gzip/unzip.c
@@ -0,0 +1,76 @@
+/* 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;
+}