3 files changed, 85 insertions, 0 deletions
diff --git a/lib/fstream/uncompress/autodetect.c b/lib/fstream/uncompress/autodetect.c
index 4ffe078..b788518 100644
--- a/lib/fstream/uncompress/autodetect.c
+++ b/lib/fstream/uncompress/autodetect.c
@@ -13,6 +13,7 @@ static const struct {
 } magic[] = {
 	{ FSTREAM_COMPRESSOR_GZIP, (const sqfs_u8 *)"\x1F\x8B\x08", 3 },
 	{ FSTREAM_COMPRESSOR_XZ, (const sqfs_u8 *)("\xFD" "7zXZ"), 6 },
+	{ FSTREAM_COMPRESSOR_ZSTD, (const sqfs_u8 *)"\x28\xB5\x2F\xFD", 4 },
 };
 
 int istream_detect_compressor(istream_t *strm,
diff --git a/lib/fstream/uncompress/istream_compressor.c b/lib/fstream/uncompress/istream_compressor.c
index 924f309..2262c9b 100644
--- a/lib/fstream/uncompress/istream_compressor.c
+++ b/lib/fstream/uncompress/istream_compressor.c
@@ -39,6 +39,11 @@ istream_t *istream_compressor_create(istream_t *strm, int comp_id)
 		comp = istream_xz_create(strm->get_filename(strm));
 #endif
 		break;
+	case FSTREAM_COMPRESSOR_ZSTD:
+#ifdef WITH_ZSTD
+		comp = istream_zstd_create(strm->get_filename(strm));
+#endif
+		break;
 	default:
 		break;
 	}
diff --git a/lib/fstream/uncompress/zstd.c b/lib/fstream/uncompress/zstd.c
new file mode 100644
index 0000000..1838af5
--- /dev/null
+++ b/lib/fstream/uncompress/zstd.c
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * zstd.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "../internal.h"
+
+#include <zstd.h>
+
+typedef struct {
+	istream_comp_t base;
+
+	ZSTD_DStream* strm;
+} istream_zstd_t;
+
+static int precache(istream_t *base)
+{
+	istream_zstd_t *zstd = (istream_zstd_t *)base;
+	istream_t *wrapped = ((istream_comp_t *)base)->wrapped;
+	ZSTD_outBuffer out;
+	ZSTD_inBuffer in;
+	size_t ret;
+
+	if (istream_precache(wrapped))
+		return -1;
+
+	memset(&in, 0, sizeof(in));
+	memset(&out, 0, sizeof(out));
+
+	in.src = wrapped->buffer;
+	in.size = wrapped->buffer_used;
+
+	out.dst = ((istream_comp_t *)base)->uncompressed + base->buffer_used;
+	out.size = BUFSZ - base->buffer_used;
+
+	ret = ZSTD_decompressStream(zstd->strm, &out, &in);
+
+	if (ZSTD_isError(ret)) {
+		fprintf(stderr, "%s: error in zstd decoder.\n",
+			wrapped->get_filename(wrapped));
+		return -1;
+	}
+
+	wrapped->buffer_offset = in.pos;
+	base->buffer_used += out.pos;
+	return 0;
+}
+
+static void cleanup(istream_comp_t *base)
+{
+	istream_zstd_t *zstd = (istream_zstd_t *)base;
+
+	ZSTD_freeDStream(zstd->strm);
+}
+
+istream_comp_t *istream_zstd_create(const char *filename)
+{
+	istream_zstd_t *zstd = calloc(1, sizeof(*zstd));
+	istream_comp_t *base = (istream_comp_t *)zstd;
+
+	if (zstd == NULL) {
+		fprintf(stderr, "%s: creating zstd decoder: %s.\n",
+			filename, strerror(errno));
+		return NULL;
+	}
+
+	zstd->strm = ZSTD_createDStream();
+	if (zstd->strm == NULL) {
+		fprintf(stderr, "%s: error creating zstd decoder.\n",
+			filename);
+		free(zstd);
+		return NULL;
+	}
+
+	((istream_t *)base)->precache = precache;
+	base->cleanup = cleanup;
+	return base;
+}