1 files changed, 89 insertions, 0 deletions
diff --git a/usr.bin/gzip/unzstd.c b/usr.bin/gzip/unzstd.c
new file mode 100644
index 000000000000..4536f3119ace
--- /dev/null
+++ b/usr.bin/gzip/unzstd.c
@@ -0,0 +1,89 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2022 Klara, Inc.
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ */
+
+/* This file is #included by gzip.c */
+
+static off_t
+unzstd(int in, int out, char *pre, size_t prelen, off_t *bytes_in)
+{
+	static char *ibuf, *obuf;
+	ZSTD_inBuffer zib;
+	ZSTD_outBuffer zob;
+	ZSTD_DCtx *zds;
+	ssize_t res;
+	size_t zres;
+	size_t bytes_out = 0;
+	int eof = 0;
+
+	if (ibuf == NULL)
+		ibuf = malloc(BUFLEN);
+	if (obuf == NULL)
+		obuf = malloc(BUFLEN);
+	if (ibuf == NULL || obuf == NULL)
+		maybe_err("malloc");
+
+	zds = ZSTD_createDStream();
+	ZSTD_initDStream(zds);
+
+	zib.src = pre;
+	zib.size = prelen;
+	zib.pos = 0;
+	if (bytes_in != NULL)
+		*bytes_in = prelen;
+	zob.dst = obuf;
+	zob.size = BUFLEN;
+	zob.pos = 0;
+
+	while (!eof) {
+		if (zib.pos >= zib.size) {
+			res = read(in, ibuf, BUFLEN);
+			if (res < 0)
+				maybe_err("read");
+			if (res == 0)
+				eof = 1;
+			infile_newdata(res);
+			zib.src = ibuf;
+			zib.size = res;
+			zib.pos = 0;
+			if (bytes_in != NULL)
+				*bytes_in += res;
+		}
+		zres = ZSTD_decompressStream(zds, &zob, &zib);
+		if (ZSTD_isError(zres)) {
+			maybe_errx("%s", ZSTD_getErrorName(zres));
+		}
+		if (zob.pos > 0) {
+			res = write(out, obuf, zob.pos);
+			if (res < 0)
+				maybe_err("write");
+			zob.pos = 0;
+			bytes_out += res;
+		}
+	}
+	ZSTD_freeDStream(zds);
+	return (bytes_out);
+}