1 files changed, 94 insertions, 0 deletions
diff --git a/lib/sqfs/test/istream_skip.c b/lib/sqfs/test/istream_skip.c
new file mode 100644
index 0000000..d8a81f2
--- /dev/null
+++ b/lib/sqfs/test/istream_skip.c
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * istream_skip.c
+ *
+ * Copyright (C) 2023 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "sqfs/io.h"
+#include "util/test.h"
+#include "io/mem.h"
+
+static const sqfs_u64 end0 = 449;	/* region 1: filled with 'A' */
+static const sqfs_u64 end1 = 521;	/* region 2: filled with 'B' */
+static const sqfs_u64 end2 = 941;	/* region 3: filled with 'C' */
+
+static sqfs_u8 rd_buffer[941];
+
+static sqfs_u8 byte_at_offset(sqfs_u64 off)
+{
+	if (off < end0)
+		return 'A';
+	if (off < end1)
+		return 'B';
+	return 'C';
+}
+
+static void init_rd_buffer(void)
+{
+	for (size_t i = 0; i < end2; ++i)
+		rd_buffer[i] = byte_at_offset(i);
+}
+
+int main(int argc, char **argv)
+{
+	sqfs_u8 read_buffer[61];
+	sqfs_u64 read_off = 0;
+	sqfs_istream_t *dummy;
+	(void)argc; (void)argv;
+
+	init_rd_buffer();
+	dummy = istream_memory_create("dummy file", 103,
+				      rd_buffer, sizeof(rd_buffer));
+	TEST_NOT_NULL(dummy);
+
+	/* region 1 */
+	while (read_off < end0) {
+		size_t read_diff = end0 - read_off;
+
+		if (read_diff > sizeof(read_buffer))
+			read_diff = sizeof(read_buffer);
+
+		int ret = sqfs_istream_read(dummy, read_buffer, read_diff);
+		TEST_ASSERT(ret > 0);
+		TEST_ASSERT((size_t)ret <= read_diff);
+
+		for (int i = 0; i < ret; ++i) {
+			TEST_EQUAL_UI(read_buffer[i], 'A');
+		}
+
+		read_off += ret;
+	}
+
+	/* region 2 */
+	{
+		int ret = sqfs_istream_skip(dummy, end2 - end1);
+		TEST_EQUAL_I(ret, 0);
+		read_off += (end2 - end1);
+	}
+
+	/* region 3 */
+	for (;;) {
+		size_t read_diff = sizeof(read_buffer);
+
+		int ret = sqfs_istream_read(dummy, read_buffer, read_diff);
+		TEST_ASSERT(ret >= 0);
+		TEST_ASSERT((size_t)ret <= read_diff);
+
+		if (ret == 0) {
+			TEST_EQUAL_UI(read_off, end2);
+			break;
+		}
+
+		for (int i = 0; i < ret; ++i) {
+			TEST_EQUAL_UI(read_buffer[i], 'C');
+		}
+
+		read_off += ret;
+		TEST_ASSERT(read_off <= end2);
+	}
+
+	sqfs_drop(dummy);
+	return EXIT_SUCCESS;
+}