Add stream I/O abstraction library

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

1 files changed, 84 insertions, 0 deletions

diff --git a/lib/fstream/ostream.c b/lib/fstream/ostream.c
new file mode 100644
index 0000000..afe76e8
--- /dev/null
+++ b/lib/fstream/ostream.c
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * ostream.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "internal.h"
+
+
+static int append_sparse_fallback(ostream_t *strm, size_t size)
+{
+	char buffer[512];
+	size_t diff;
+
+	memset(buffer, 0, sizeof(buffer));
+
+	while (size > 0) {
+		diff = size < sizeof(buffer) ? size : sizeof(buffer);
+
+		if (strm->append(strm, buffer, diff))
+			return -1;
+
+		size -= diff;
+	}
+
+	return 0;
+}
+
+
+int ostream_append(ostream_t *strm, const void *data, size_t size)
+{
+	return strm->append(strm, data, size);
+}
+
+int ostream_append_sparse(ostream_t *strm, size_t size)
+{
+	if (strm->append_sparse == NULL)
+		return append_sparse_fallback(strm, size);
+
+	return strm->append_sparse(strm, size);
+}
+
+int ostream_flush(ostream_t *strm)
+{
+	return strm->flush(strm);
+}
+
+const char *ostream_get_filename(ostream_t *strm)
+{
+	return strm->get_filename(strm);
+}
+
+sqfs_s32 ostream_append_from_istream(ostream_t *out, istream_t *in,
+				     sqfs_u32 size)
+{
+	sqfs_s32 total = 0;
+	size_t diff;
+
+	if (size > 0x7FFFFFFF)
+		size = 0x7FFFFFFF;
+
+	while (size > 0) {
+		if (in->buffer_offset >= in->buffer_used) {
+			if (istream_precache(in))
+				return -1;
+
+			if (in->buffer_used == 0)
+				break;
+		}
+
+		diff = in->buffer_used - in->buffer_offset;
+		if (diff > size)
+			diff = size;
+
+		if (out->append(out, in->buffer + in->buffer_offset, diff))
+			return -1;
+
+		in->buffer_offset += diff;
+		size -= diff;
+		total += diff;
+	}
+
+	return total;
+}