1 files changed, 81 insertions, 0 deletions
diff --git a/lib/io/uncompress/zstd.c b/lib/io/uncompress/zstd.c
new file mode 100644
index 0000000..fd22cbf
--- /dev/null
+++ b/lib/io/uncompress/zstd.c
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * zstd.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "../internal.h"
+
+#include <zstd.h>
+
+#ifdef HAVE_ZSTD_STREAM
+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;
+}
+#endif /* HAVE_ZSTD_STREAM */