Implement ostream compressor wrapper

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

1 files changed, 80 insertions, 0 deletions

diff --git a/lib/fstream/compress/xz.c b/lib/fstream/compress/xz.c
new file mode 100644
index 0000000..65bda0b
--- /dev/null
+++ b/lib/fstream/compress/xz.c
@@ -0,0 +1,80 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * xz.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "../internal.h"
+
+#include <lzma.h>
+
+typedef struct {
+	ostream_comp_t base;
+
+	lzma_stream strm;
+} ostream_xz_t;
+
+static int flush_inbuf(ostream_comp_t *base, bool finish)
+{
+	ostream_xz_t *xz = (ostream_xz_t *)base;
+	lzma_ret ret_xz;
+	size_t have;
+
+	xz->strm.next_in = base->inbuf;
+	xz->strm.avail_in = base->inbuf_used;
+
+	do {
+		xz->strm.next_out = base->outbuf;
+		xz->strm.avail_out = BUFSZ;
+
+		ret_xz = lzma_code(&xz->strm, finish ? LZMA_FINISH : LZMA_RUN);
+
+		if ((ret_xz != LZMA_OK) && (ret_xz != LZMA_STREAM_END)) {
+			fprintf(stderr,
+				"%s: internal error in XZ compressor.\n",
+				base->wrapped->get_filename(base->wrapped));
+			return -1;
+		}
+
+		have = BUFSZ - xz->strm.avail_out;
+
+		if (base->wrapped->append(base->wrapped, base->outbuf, have))
+			return -1;
+	} while (xz->strm.avail_out == 0);
+
+	base->inbuf_used = 0;
+	return 0;
+}
+
+static void cleanup(ostream_comp_t *base)
+{
+	ostream_xz_t *xz = (ostream_xz_t *)base;
+
+	lzma_end(&xz->strm);
+}
+
+ostream_comp_t *ostream_xz_create(const char *filename)
+{
+	ostream_xz_t *xz = calloc(1, sizeof(*xz));
+	ostream_comp_t *base = (ostream_comp_t *)xz;
+	lzma_ret ret_xz;
+
+	if (xz == NULL) {
+		fprintf(stderr, "%s: creating xz wrapper: %s.\n",
+			filename, strerror(errno));
+		return NULL;
+	}
+
+	ret_xz = lzma_easy_encoder(&xz->strm, LZMA_PRESET_DEFAULT,
+				   LZMA_CHECK_CRC64);
+	if (ret_xz != LZMA_OK) {
+		fprintf(stderr, "%s: error initializing XZ compressor\n",
+			filename);
+		free(xz);
+		return NULL;
+	}
+
+	base->flush_inbuf = flush_inbuf;
+	base->cleanup = cleanup;
+	return base;
+}