Implement ostream compressor wrapper

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

1 files changed, 98 insertions, 0 deletions

diff --git a/lib/fstream/compress/ostream_compressor.c b/lib/fstream/compress/ostream_compressor.c
new file mode 100644
index 0000000..5137f1d
--- /dev/null
+++ b/lib/fstream/compress/ostream_compressor.c
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * ostream_compressor.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "../internal.h"
+
+static int comp_append(ostream_t *strm, const void *data, size_t size)
+{
+	ostream_comp_t *comp = (ostream_comp_t *)strm;
+	size_t diff;
+
+	while (size > 0) {
+		if (comp->inbuf_used >= BUFSZ) {
+			if (comp->flush_inbuf(comp, false))
+				return -1;
+		}
+
+		diff = BUFSZ - comp->inbuf_used;
+
+		if (diff > size)
+			diff = size;
+
+		memcpy(comp->inbuf + comp->inbuf_used, data, diff);
+
+		comp->inbuf_used += diff;
+		data = (const char *)data + diff;
+		size -= diff;
+	}
+
+	return 0;
+}
+
+static int comp_flush(ostream_t *strm)
+{
+	ostream_comp_t *comp = (ostream_comp_t *)strm;
+
+	if (comp->inbuf_used > 0) {
+		if (comp->flush_inbuf(comp, true))
+			return -1;
+	}
+
+	return comp->wrapped->flush(comp->wrapped);
+}
+
+static const char *comp_get_filename(ostream_t *strm)
+{
+	ostream_comp_t *comp = (ostream_comp_t *)strm;
+
+	return comp->wrapped->get_filename(comp->wrapped);
+}
+
+static void comp_destroy(sqfs_object_t *obj)
+{
+	ostream_comp_t *comp = (ostream_comp_t *)obj;
+
+	comp->cleanup(comp);
+	sqfs_destroy(comp->wrapped);
+	free(comp);
+}
+
+ostream_t *ostream_compressor_create(ostream_t *strm, int comp_id)
+{
+	ostream_comp_t *comp = NULL;
+	sqfs_object_t *obj;
+	ostream_t *base;
+
+	switch (comp_id) {
+	case FSTREAM_COMPRESSOR_GZIP:
+#ifdef WITH_GZIP
+		comp = ostream_gzip_create(strm->get_filename(strm));
+#endif
+		break;
+	case FSTREAM_COMPRESSOR_XZ:
+#ifdef WITH_XZ
+		comp = ostream_xz_create(strm->get_filename(strm));
+#endif
+		break;
+	default:
+		break;
+	}
+
+	if (comp == NULL)
+		return NULL;
+
+	comp->wrapped = strm;
+	comp->inbuf_used = 0;
+
+	base = (ostream_t *)comp;
+	base->append = comp_append;
+	base->flush = comp_flush;
+	base->get_filename = comp_get_filename;
+
+	obj = (sqfs_object_t *)comp;
+	obj->destroy = comp_destroy;
+	return base;
+}