Add zstd stream compressor implementation to libfstream

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 92 insertions, 0 deletions

diff --git a/lib/fstream/compress/zstd.c b/lib/fstream/compress/zstd.c
new file mode 100644
index 0000000..f4f7f86
--- /dev/null
+++ b/lib/fstream/compress/zstd.c
@@ -0,0 +1,92 @@
+/* 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 {
+	ostream_comp_t base;
+
+	ZSTD_CStream *strm;
+} ostream_zstd_t;
+
+static int flush_inbuf(ostream_comp_t *base, bool finish)
+{
+	ostream_zstd_t *zstd = (ostream_zstd_t *)base;
+	ZSTD_EndDirective op;
+	ZSTD_outBuffer out;
+	ZSTD_inBuffer in;
+	size_t ret;
+
+	op = finish ? ZSTD_e_end : ZSTD_e_continue;
+
+	do {
+		memset(&in, 0, sizeof(in));
+		memset(&out, 0, sizeof(out));
+
+		in.src = base->inbuf;
+		in.size = base->inbuf_used;
+
+		out.dst = base->outbuf;
+		out.size = BUFSZ;
+
+		ret = ZSTD_compressStream2(zstd->strm, &out, &in, op);
+
+		if (ZSTD_isError(ret)) {
+			fprintf(stderr, "%s: error in zstd compressor.\n",
+				base->wrapped->get_filename(base->wrapped));
+			return -1;
+		}
+
+		if (base->wrapped->append(base->wrapped, base->outbuf,
+					  out.pos)) {
+			return -1;
+		}
+
+		if (in.pos < in.size) {
+			base->inbuf_used = in.size - in.pos;
+
+			memmove(base->inbuf, base->inbuf + in.pos,
+				base->inbuf_used);
+		} else {
+			base->inbuf_used = 0;
+		}
+	} while (finish && ret != 0);
+
+	return 0;
+}
+
+static void cleanup(ostream_comp_t *base)
+{
+	ostream_zstd_t *zstd = (ostream_zstd_t *)base;
+
+	ZSTD_freeCStream(zstd->strm);
+}
+
+ostream_comp_t *ostream_zstd_create(const char *filename)
+{
+	ostream_zstd_t *zstd = calloc(1, sizeof(*zstd));
+	ostream_comp_t *base = (ostream_comp_t *)zstd;
+
+	if (zstd == NULL) {
+		fprintf(stderr, "%s: creating zstd wrapper: %s.\n",
+			filename, strerror(errno));
+		return NULL;
+	}
+
+	zstd->strm = ZSTD_createCStream();
+	if (zstd->strm == NULL) {
+		fprintf(stderr, "%s: error creating zstd decoder.\n",
+			filename);
+		free(zstd);
+		return NULL;
+	}
+
+	base->flush_inbuf = flush_inbuf;
+	base->cleanup = cleanup;
+	return base;
+}